JP2021163942A - Winding iron core, manufacturing method of winding iron core, and winding iron core manufacturing device - Google Patents

Abstract

To provide a winding iron core which can be manufactured from a distortion application type magnetic domain control material without a distortion removing sinter pure step, a manufacturing method of the winding iron core, and a winding iron core manufacturing device.SOLUTION: A winding iron core 10 of the present invention is formed so that distortion 20 for controlling each magnetic domain extended in a width direction crossed to a pressure extension direction individually folds and processes a directional electromagnetic steel plate 40 applied to a front face, and is assembled in a winding shape. In a portion which becomes a folding part R1 and its neighborhood region in the folding processing, a groove 25 extended in the width direction is formed on the front face of the directional electromagnetic steel plate 40.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wound iron core, a method for producing a wound iron core, and a wound iron core manufacturing apparatus.

There are two types of iron cores for transformers: stacked iron cores and wound iron cores. Of these, the wound iron core is generally manufactured by stacking directional electromagnetic steel sheets in layers, winding them in a donut shape (winding shape), and then pressurizing the wound body to form a substantially square shape. NS. This forming process causes mechanical machining strain (plastic deformation strain) to be applied to the entire grain-oriented electrical steel sheet, and the machining strain causes the iron loss of the grain-oriented electrical steel sheet to be significantly deteriorated. be.

As the grain-oriented electrical steel sheet used for the iron core, a grain-oriented electrical steel sheet, which is an electromagnetic steel sheet having easily magnetized axes aligned in one direction, is used. For such grain-oriented electrical steel sheets, the surface of the grain-oriented electrical steel sheets is periodically laser-irradiated in a direction intersecting the rolling direction to locally quench (and rapidly cool from rapid heating to room temperature). By performing this, a plurality of thin strains (strains for controlling magnetic domains) are introduced, and the 180 ° magnetic domain is subdivided starting from the recirculation magnetic domain generated at that site to reduce iron loss, so-called strain imparting. There is a type magnetic domain control material (see, for example, Patent Document 1). However, when a grain-oriented electrical steel sheet, which is a strain-imparting type magnetic domain control material to which such strain for magnetic domain control is applied, is used for the wound iron core, the strain-removing annealing step described above is performed. Since the strain that is the starting point for magnetic domain control and the strain (including machining strain) disappear, the magnetic domain control effect also disappears, and the wound iron core with low iron loss cannot be obtained. Therefore, the strain-imparting magnetic domain control material is generally used only for a steel core that does not require a pressure forming or annealing step.

In addition, by forming grooves on the surface of the grain-oriented electrical steel sheet periodically in the direction intersecting the rolling direction, the 180 ° magnetic domain was subdivided and iron loss was reduced by the same effect as the reflux magnetic domain. There is also a so-called groove-forming type magnetic domain control material that obtains a magnetic domain control effect in which iron loss is reduced (see, for example, Patent Document 2). Such a groove-forming type magnetic domain control material can be used as a material for a wound iron core because the magnetic domain control effect is not lost even if strain relief annealing is performed. However, the groove-forming type iron loss improving effect (magnetic domain control effect) has a drawback that it is smaller than the strain-imparting type iron loss improving effect. Further, as a method of forming a groove, machining by a tooth profile press and chemical processing by etching are put into practical use, and such a method is a non-contact type, such as a laser or an electron beam that imparts distortion for magnetic domain control. Compared to the method of irradiating the tooth profile, the tooth profile press has problems such as large-scale mechanical equipment and wear of the tooth profile, and the etching method requires waste liquid treatment and a mask, which is costly and production. There was a capacity problem. As a groove forming method, a groove processing method that irradiates a laser or an electron beam has an advantage of being a non-contact type, but this groove processing method using a laser or an electron beam imparts distortion for magnetic domain control. Since a large amount of power is required as compared with the case where the method is used, there is a problem that the production capacity and the cost increase when the groove is formed on the entire surface of the directional electromagnetic steel plate.

By the way, in recent years, as a method for manufacturing a wound iron core, steel plates are individually bent (for each very small number of sheets such as one or two) and cut, and the individually processed steel sheets are laminated over a plurality of layers. As a result, a method of forming a wound iron core into a square shape (so-called "unicore" wound iron core manufacturing method; hereinafter, also referred to as a unicore manufacturing method) has come to be known. By using such a method, the curvature R of the bent portion can be made extremely small, and the value of the curvature R measured inside the steel sheet can be set to 3 mm or less, which is introduced into the steel sheet due to the bending process. It is possible to limit the range covered by the machining strain to only the vicinity of a small bent portion defined so that the curvature R is 3 mm or less. The lower limit of the curvature R is not particularly limited, but it depends on the ability of the bending device and the like, and in reality, it is often about 1 mm.
When the wound iron core is manufactured by this method, since the local bending process is performed, the processing strain is generated only in the region near the corner portion caused by the bending, so that the wound iron core as a whole There is an advantage that iron loss deterioration can be reduced and therefore strain removal annealing can be eliminated. Therefore, a strain-imparting magnetic domain control material having extremely low iron loss can be used as the material for the wound iron core.

That is, as can be seen from the above, the strain-imparting magnetic domain control material has a drawback that the iron loss does not decrease due to the disappearance of strain due to the strain-removing annealing step when used for a wound iron core. Since it has the advantage of being more effective in improving iron loss and being cheaper than the formation-type magnetic domain control material, a wound iron core is manufactured using a strain-imparting magnetic domain control material by the Unicore manufacturing method that can eliminate the strain-removing annealing process. By doing so, it is possible to eliminate the drawbacks of the strain-imparting magnetic domain control material and make full use of its advantages.

Japanese Unexamined Patent Publication No. 2003-347128 International Publication No. 2011/125672

However, even when the wound steel core is manufactured by the strain-imparted magnetic domain control material (oriented electrical steel sheet whose magnetic domain is controlled by the strain-applied type) by the Unicore manufacturing method, it still becomes a corner when bent. Since processing strain (plastic deformation strain) remains in or near the portion, deterioration of iron loss occurs in such a region. Therefore, it is required to improve the deterioration of iron loss due to the machining strain, which remains in the corner portion and the vicinity thereof in the bending process.

The present invention has been made in view of the above circumstances, and is a wound iron core that can be manufactured by a strain-imparting magnetic domain control material without a strain-removing annealing step and can suppress iron loss deterioration due to machining strain of a bent portion. , A method of manufacturing a wound iron core and an apparatus for producing a wound iron core.

In order to achieve the above object, the present invention individually bends a grain-oriented electrical steel sheet to which a strain for controlling a magnetic domain extending in a width direction intersecting a rolling direction is applied to the surface and assembles it into a wound shape. A groove extending in the width direction is formed on the surface of the grain-oriented electrical steel sheet in a portion of the wound steel core formed by attaching the steel core, which becomes a bent portion in the bending process and a region in the vicinity thereof. , Provides a wound steel core.

The wound steel core of the present invention according to the above configuration is a wound steel core formed of a grain-oriented electrical steel sheet in which iron loss is improved by applying strain for controlling magnetic zones to the surface of the steel sheet to form a reflux magnetic zone. Each grain-oriented electrical steel sheet that has been individually bent is stacked in layers and assembled into a wound shape (manufactured by the Unicore manufacturing method that does not perform strain removal and annealing), and is folded in the bending process of each grain-oriented electrical steel sheet. It is a wound steel core in which a plurality of grooves extending in a direction intersecting the rolling direction of a steel sheet are formed in and near a portion to be a curved portion.

When the grain-oriented electrical steel sheet is locally bent, processing strain occurs in the range of several mm to several tens of mm from the vicinity of the bent portion. This machining strain becomes a factor that deteriorates the iron loss of the grain-oriented electrical steel sheet, and forms a reflux magnetic domain starting from the strain for periodic magnetic domain control (strain for controlling a plurality of magnetic domains separated from each other by a predetermined interval). When a grain-oriented electrical steel sheet with magnetic domain control is used, there is a problem that the iron loss improvement allowance is offset. Therefore, the present inventors have focused on the fact that machining strain is generated in the vicinity of the bent portion due to the tension generated mainly in the bending direction starting from the bent portion, and several mm to several tens around the bent portion. It was found that when grooves were periodically formed in the range of mm almost perpendicular to the tension direction (multiple grooves were formed at predetermined intervals from each other), the iron loss of the entire iron core was improved by several percent. .. It is presumed that this is because the stress was relaxed by the groove formation and the influence of the machining strain was relaxed. Further, since the periodic groove formation has a magnetic domain control effect, it is considered that this also contributes to the improvement of iron loss.

Examples of the method for forming the groove include etching, mechanical pressing, electron beam, laser and the like. However, etching requires waste liquid treatment, mechanical presses have a tooth profile life, and electron beams require a vacuum chamber, which increases the size and cost of the equipment, so non-contact processing is possible in the atmosphere. It is preferable to form the groove by a suitable laser processing method. Further, such a groove formed in and / or in the vicinity of the bent portion of each grain-oriented electrical steel sheet is provided in place of or in addition to the strain for controlling the magnetic domain.

Further, the present invention comprises a strain applying step of irradiating the surface of a grain-oriented electrical steel sheet with a beam to impart a strain for controlling a magnetic zone extending in a width direction intersecting the rolling direction of the grain-oriented electrical steel sheet. By irradiating the surface of the grain-oriented electrical steel sheet with a beam, a groove forming step for forming a groove extending in the width direction of the grain-oriented electrical steel sheet, and the direction in which the strain for controlling the magnetic zone is applied and the groove is formed. A bending step in which the electrical steel sheets are individually bent, and an assembly step in which the electrical steel sheets that have been bent are assembled in a wound shape to form a wound steel core. The strain applying step applies strain for controlling the magnetic zone in a region other than the portion to be a bent portion in the bending process and its vicinity on the surface of the grain-oriented electrical steel sheet, and the groove is formed. The forming step provides a method for manufacturing a wound steel core, which forms the groove in a portion of the surface of the grain-oriented electrical steel sheet that becomes a bent portion in the bending process and a region in the vicinity thereof.

Further, in the present invention, by irradiating the surface of the grain-oriented electrical steel sheet with a beam, strain for controlling the magnetic zone extending in the width direction intersecting the rolling direction of the grain-oriented electrical steel sheet is applied, and the grain-oriented electrical steel sheet is subjected to a strain for controlling the magnetic zone. By irradiating the surface with a beam, a beam irradiation portion that forms a groove extending in the width direction of the grain-oriented electrical steel sheet, and the grain-oriented electrical steel sheet to which strain for magnetic zone control is applied and the groove is formed are formed. The beam irradiation unit has a bending portion that is individually bent and an assembly portion that forms a wound iron core by assembling the bent electromagnetic steel sheet into a wound shape. On the surface of the grain-oriented electrical steel sheet, the strain for controlling the magnetic zone is applied in a region other than the portion to be a bent portion in the bending process and its vicinity, and the surface of the grain-oriented electrical steel sheet Provided is a winding iron core manufacturing apparatus for forming the groove in a portion to be a bent portion in the bending process and a region in the vicinity thereof.

For the method and apparatus for manufacturing the wound iron core having the above configuration, an electromagnetic steel sheet that is not subjected to magnetic domain control is prepared, and the electromagnetic steel sheet is irradiated with a beam such as a laser or an electron beam to serve as the starting point of the magnetic domain. A unicore manufacturing method is adopted in which strain for magnetic domain control is applied to control magnetic domains, and each grain-oriented electrical steel sheet is bent, stacked in layers, and assembled into a wound shape to form a wound iron core. do.

Further, in the manufacturing method and the manufacturing apparatus having the above configuration, the same beam irradiation apparatus is used, and by changing the beam irradiation conditions, groove addition to the surface of the grain-oriented electrical steel sheet and strain addition for magnetic domain control are switched. You may do so. Here, examples of the beam irradiated by the beam irradiating device include a laser and an electron beam.

Further, in the present invention, by irradiating the surface with a beam, a grain-oriented electrical steel sheet to which a strain for controlling a magnetic domain extending in a width direction intersecting the rolling direction is applied is separately obtained, and the strain for controlling such a magnetic domain is generated separately. Grooves may be formed with respect to the imparted grain-oriented electrical steel sheet.

Since the wound steel core of the present invention is formed by assembling individually bent grain-oriented electrical steel sheets in a donut shape (winding shape), strain-applying magnetic domain control without a strain-removing annealing step. It can be manufactured from wood, and since grooves extending in the width direction of the grain-oriented electrical steel sheet are formed in and near the bent portion in the bending process of the grain-oriented electrical steel sheet, it accompanies the machining strain of the grained grain. It is possible to suppress deterioration of iron loss.

A perspective view of a wound iron core according to an embodiment of the present invention is shown, and an enlarged layer cross section including a linear groove is included in a bent portion of each grain-oriented electrical steel sheet constituting the wound iron core. It is a figure which shows what the iron loss of the wound iron core of this invention becomes when the iron loss of the wound iron core of the comparative example is 100. It is sectional drawing which shows the formation form of the groove around the bent part at the time of bending process of the grain-oriented electrical steel sheet which constitutes the wound iron core which concerns on one Embodiment of this invention. It is a figure which shows the relationship between the groove formation range and iron loss ratio at various groove intervals (laser irradiation pitch). It is a schematic perspective view of the manufacturing method and the manufacturing apparatus of the wound iron core which concerns on one Embodiment of this invention. It is a schematic schematic diagram which shows the manufacturing method of the wound iron core which concerns on one Embodiment of this invention, and the laser irradiation mode in the manufacturing apparatus, (a) shows a laser irradiation apparatus and its scanning direction, (b) is light-collecting. The beam shape is shown.

Hereinafter, the wound iron core, the method for manufacturing the wound iron core, and the wound iron core manufacturing apparatus according to the embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a wound iron core 10 according to an embodiment of the present invention. The wound iron core 10 has a substantially rectangular parallelepiped shape having a hollow portion 15, and its corner portion R is locally bent by using a unicore manufacturing method. Further, the wound steel core 10 extends on the surface of the grain-oriented electrical steel sheet 40 linearly or with curvature in a direction intersecting the rolling direction (longitudinal direction) D of the grain-oriented electrical steel sheet 40. Is formed from a plurality of grain-oriented electrical steel sheets 40 in which the iron loss is improved by subdividing the 180 ° magnetic section starting from the reflux magnetic section. The wound iron core 10 is formed by stacking individually bent directional electromagnetic steel sheets (in the present embodiment, the thickness and width thereof are the same) 40 in layers and assembling them in a donut shape (wound shape). (See also FIG. 5). Since the local bending process is performed, the processing strain (plastic deformation strain) is generated only in the vicinity of the bent portion, so that the deterioration of the iron loss of the wound iron core 10 as a whole can be reduced. Therefore, the grain-oriented electrical steel sheet 40 according to the present embodiment does not need to be strain-removed and annealed before and after laminating.

Specifically, the strain 20 for magnetic domain control is introduced on the surface of the grain-oriented electrical steel sheet 40 at a predetermined interval Pl (for example, 4 mm), and the recirculation magnetic domain starts from the strain 20 for magnetic domain control. The 180 ° magnetic domain, which is the magnetic domain in the longitudinal direction D of the grain-oriented electrical steel sheet 40, is subdivided, and the iron loss is improved by about 10% as compared with that before the introduction of the strain 20 for controlling the magnetic domain.

Further, in the present embodiment, at the corners (hence, the four corners of the wound steel core 10) when the grain-oriented electrical steel sheet 40 is bent, the bent portion, which is the point at which the grain-oriented electrical steel sheet bends, and the bent portion thereof. In the vicinity region, a plurality of grooves 25 extending linearly or with a curvature in a direction intersecting the rolling direction D of the grain-oriented electrical steel sheet 40 are formed at predetermined intervals.

These grooves 25 are formed by rolling the grain-oriented electrical steel sheet 40 on both sides of a portion (top. Bent portion) R1 where the grain-oriented electrical steel sheet 40 bends at a corner portion R when the grain-oriented electrical steel sheet 40 is bent. It is formed at intervals of 2 mm to 10 mm Pl over a range (groove formation range) X of 1 mm to 50 mm along the direction D. For example, the grooves 25 can be formed at intervals of 4 mm by laser processing within the groove forming range X of 25 mm on both sides of the bent portion R1 at the corner portion R, and the depth of the grooves 25 can be set to 25 μm on average.
In FIG. 1, the groove 25 formed in the bent R1 and the region in the vicinity thereof (that is, corresponding to the groove forming range X) is shown by a solid line, and the other surface of the grain-oriented electrical steel sheet 40 is shown. A plurality of magnetic domain control strains 20 formed over the entire area are partially shown by broken lines.

Further, the wound iron core 10 according to the present embodiment becomes a transformer by winding, for example, a primary winding and a secondary winding (not shown) so as to penetrate the hollow portion 15, and is a primary winding. When a current is passed through the wire or the secondary winding, a magnetic circuit of magnetic flux circulating around the hollow portion 15, that is, a closed magnetic path is formed. Further, the grain-oriented electrical steel sheet 40 according to the present embodiment is an electrical steel sheet in which the directions of the easy-to-magnetize axes of the crystal grains (the <100> direction of the body-centered cubic crystal) are substantially aligned with the rolling direction D, and are rolled. It has a structure in which a plurality of magnetic domains whose magnetization is oriented in the direction D are arranged with a magnetic domain wall in between. Such a grain-oriented electrical steel sheet 40 is suitable as an iron core material for a transformer in which the lines of magnetic force are directed in a certain direction. Here, the easily magnetized shaft of the grain-oriented electrical steel sheet 40 is assembled in the wound iron core 10 so as to correspond to the circumferential direction of the wound iron core 10 (the direction of circulating around the hollow portion 15).

FIG. 2 is a diagram showing how the iron loss of the wound iron core 10 according to the present embodiment becomes when the iron loss of the wound iron core of the comparative example is 100. The wound iron core of the comparative example is provided with the same magnetic domain control strain 20 as the wound iron core 10 according to the present embodiment, but the bent portion R1 and the region in the vicinity thereof when being bent are subjected to the same strain 20. , The groove 25 is not formed. As shown in FIG. 2, the wound iron core 10 of the present invention can realize an iron loss reduction of about 2% with respect to the wound iron core of the comparative example.

FIG. 3 is a cross-sectional view showing a form of forming a groove 25 around the bent portion R1 when the grain-oriented electrical steel sheet 40 constituting the wound iron core 10 according to the present embodiment shown in FIG. 1 is bent. , The formation interval Pl of the groove 25, the bent portion R1 at the corner portion R of the grain-oriented electrical steel sheet 40, and the groove formation range X are shown. In this example, the groove 25 is formed directly above the bent portion R1 of the corner portion R of the grain-oriented electrical steel sheet 40, and another groove 25 is formed at _{a distance Pl 0 of 1 mm from the bent portion R1.}

FIG. 4 shows the relationship between the groove formation range X (mm) and the iron loss ratio at various intervals Pl (laser irradiation pitch) of the grooves 25. FIG. 4 shows the results of comparing the iron losses by manufacturing the corresponding wound iron cores by changing the spacing Pl of the grooves 25 from 1 mm to 12 mm and changing the groove formation range X up to a maximum of 70 mm. .. Further, the iron loss ratio in FIG. 4 is a relative value of the iron loss when the value of the iron loss in the wound iron core not forming the groove 25 is 100.

As can be seen from FIG. 4, when P1 = 1 mm, the iron loss increased as the groove formation range X widened. This is because the effect of reducing the iron loss improving effect due to the change from magnetic domain control strain application to groove formation is greater than the effect of alleviating the processing strain caused by bending, and the entire groove formation range X This is because the iron loss as a result was increased. Further, when Pl = 2 mm, the iron loss is less than 100, and when Pl = 4 mm and Pl = 6 mm, the iron loss is reduced by up to 2% when the groove formation range X is about 20 mm to 40 mm. bottom. On the other hand, when Pl increases, the iron loss reduction effect decreases, but the iron loss tends to decrease until Pl = 10 mm, and when Pl exceeds 10 mm, the iron loss is equivalent to the case where the groove 25 is not formed. .. It is considered that this is because when the groove spacing Pl becomes large, the stress applied to alleviate the processing strain generated by the bending process becomes insufficient. Further, even if Pl = 10 mm or less, iron loss increases when the groove formation range X exceeds 50 mm. This is because the effect of improving the iron loss by applying the strain 20 for magnetic domain control became smaller, and the effect of the processing strain generated by the bending process became relatively large, so that the iron loss deteriorated. It is considered to be.

Therefore, the groove 25 is 2 mm in the range of 1 mm to 50 mm in the rolling direction D of the grain-oriented electrical steel sheet 40, which can be regarded as being close to the bent portion R1 at the corner portion R generated in the bending process of the grain-oriented electrical steel sheet 40. It can be said that it is preferably formed with a groove spacing of 10 mm.

FIG. 5 schematically shows a method and an apparatus for manufacturing a wound iron core according to an embodiment of the present invention.
First, the winding iron core manufacturing apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 5, the wound steel core manufacturing apparatus according to the present embodiment is, for example, from a steel sheet supply unit 50 that holds a hoop material 40a formed by winding a grain-oriented electrical steel sheet 40, from a grain-oriented electrical steel sheet. By feeding the 40 at a transport speed V1 (for example, 30 m / s), the grain-oriented electrical steel sheet 40 is supplied.

The width direction of the grain-oriented electrical steel sheet 40, which irradiates the surface of the grain-oriented electrical steel sheet 40 supplied from the steel sheet supply section 50 with the beam 90 from the beam irradiation section 52 and intersects the rolling direction D of the grain-oriented electrical steel sheet 40. A plurality of strains 20 for controlling magnetic zones extending to W are applied at predetermined intervals Pl. The type of beam emitted from the beam irradiation unit 52 is not particularly limited. A laser is preferable because a high-energy light source can be easily and inexpensively obtained, but an electron beam or the like can also be used in the same manner as a laser.

The magnetic domain-controlled directional electromagnetic steel sheet 40 to which strain 20 for magnetic domain control is applied by the bending section 54 is cut into an appropriate size and individually bent in small numbers, such as one by one. , Perform bending (that is, use the Unicore manufacturing method). In the grain-oriented electrical steel sheet 40 thus obtained, the curvature of the bent portion R1 at the corner portion R generated by the bending process is extremely small, so that the processing strain applied to the grain-oriented electrical steel sheet 40 by the bending process is extremely small. It will be small.
The wound iron core 10 is manufactured by stacking the bent directional electromagnetic steel sheets 40 in layers and assembling them into a wound shape by the assembling portion 56 (not shown).

The control unit 58 is connected to the steel plate supply unit 50, the beam irradiation unit 52, the bending unit 54, and the assembly unit 56 directly or via a network or the like by wire or wirelessly (a part of the figure is omitted). ).
In the control unit 58, which part of the (for example, long) grain-oriented electrical steel sheet 40 supplied from the steel plate supply unit 50 is the position of the bending portion R1 at the time of bending that is bent by the bending unit 54. Is calculated based on the signal S1 from the bending unit 54.
Then, the control unit 58 synchronizes the operation of the beam irradiation unit 52 with the operation of the steel plate supply unit 50 by outputting the signal S2 to the beam irradiation unit 52, and the directional electromagnetic steel plate 40 supplied from the steel plate supply unit 50. The operation of the beam irradiation unit 52 is controlled so that the beam irradiation can be performed based on the portion that becomes the bent portion R1 during the bending process.

For example, by controlling the control unit 58, the beam irradiation conditions (power, focusing shape, and irradiation speed of the beam) of the beam irradiation unit 52 can be set to conditions for irradiating a beam having a relatively low power density. A strain 20 for controlling the magnetic domain is applied to the entire surface region of the electrical steel sheet 40, while the beam irradiation portion 52 is applied to the portion that becomes the bent portion R1 in the bending process and the region in the vicinity thereof. By setting the beam irradiation condition to irradiate a beam having a higher power density, the groove 25 can be formed (overwriting) on the applied strain 20 for magnetic domain control.

Further, under the control of the control unit 58, the beam irradiation condition of the beam irradiation unit 52 is set to the condition of irradiating a beam having a relatively low power density for the region other than the portion that becomes the bending portion R1 in the bending process and its vicinity. By setting, the strain 20 for magnetic domain control is applied, while the beam irradiation condition of the beam irradiation unit 52 is set to a higher power density in the portion that becomes the bent portion R1 in the bending process and the region in the vicinity thereof. The beam may be switched so as to form the groove 25 by switching to the condition of irradiating the beam having a high density.

Next, a method for manufacturing the wound iron core according to the present embodiment will be described with reference to FIG.
The hoop material 40a is a roll of a long directional electromagnetic steel sheet 40 that is not subjected to magnetic domain control by applying strain for magnetic domain control. The hoop material 40a unwound from the steel plate supply unit 50 is conveyed toward the beam irradiation unit 52 at a controlled constant speed V1. By irradiating the directional electromagnetic steel sheet 40 with a beam such as laser light from the beam irradiating device 52A and scanning the directional electromagnetic steel sheet 40 in the width direction W, the strain 20 for controlling the magnetic zone extending in the width direction W is directional electromagnetic. It is formed on the surface of the steel plate 40 (strain applying step). The strain 20 for magnetic domain control is limited to a region other than the portion that becomes the bent portion R1 at the time of bending and the vicinity thereof on the surface of the grain-oriented electrical steel sheet 40, and the rolling direction of the grain-oriented electrical steel sheet 40. It is preferable to apply the magnetic domain control strain 20 extending in the width direction W intersecting with D, but the magnetic domain control strain is applied to the entire grain-oriented electrical steel sheet 40, and then the grooves are formed in the groove forming step described later. 25 may be formed by overwriting.

Further, in addition to applying the strain 20 for controlling the magnetic domain described above, the beam irradiating unit 52 is directional in the portion of the surface of the grain-oriented electrical steel sheet 40 that becomes the bent portion R1 in the bending process and the region in the vicinity thereof. A groove 25 extending in the width direction W intersecting the rolling direction D of the electrical steel sheet 40 is also formed (groove forming step).

Further, in the bending section 54, the strain 20 for magnetic domain control is applied in the strain applying step, and the grain-oriented electrical steel sheets 40 in which the grooves 25 are formed in the groove forming step are formed one by one. Bending is performed individually (that is, the Unicore manufacturing method is used) (folding step). In the grain-oriented electrical steel sheet 40 thus obtained, the curvature of the bent portion R1 generated by the bending process is extremely small, so that the machining strain applied to the grain-oriented electrical steel sheet 40 by the bending process is extremely small. ..
The assembling portion 56 forms the wound iron core 10 by assembling the bent directional electromagnetic steel plate 40 into a wound shape (assembling step).

FIG. 6 schematically shows a beam irradiation mode in the beam irradiation unit 52. The type of beam emitted from the beam irradiation unit 52 is not particularly limited, and may be, for example, a laser or an electron beam. The beam light is guided from a beam light source (not shown) to a beam emitting part by an optical fiber or a mirror reflection transmission system (not shown), and is provided by a polyhedral rotating polygon mirror in the beam irradiation device 52A or a vibration mirror by a galvano motor. It is scanned in the width direction W of the directional electromagnetic steel plate 40, collected by an fθ lens or a parabolic mirror, and irradiated to the directional electromagnetic steel plate 40.

Further, as an example of the condition of the beam irradiation condition when the strain 20 for magnetic domain control is applied and when the groove 25 is formed, an example of the condition when a laser is used is given when the strain 20 for magnetic domain control is applied. Has an elliptical shape in which the laser power P is 300 W, the diameter dx in the beam scanning direction is 0.1 mm, and the diameter dy in the orthogonal direction is 4.0 mm, and the beam scanning speed Vx is 20 m / s. Can be set as. On the other hand, when the groove 25 is formed, the laser power P is 2000 W, and the condensing shape is an elliptical shape in which the diameter dx in the beam scanning direction is 0.05 mm and the diameter dy in the orthogonal direction is 0.3 mm. The scanning speed Vx can be set to 30 m / s. The beam power is changed by the power adjustment function of the beam irradiation device 52A, the focusing diameter is changed by the beam enlargement / focusing function in the beam irradiation device 52A, and the scanning speed is changed. , It may be performed by changing the speed of the vibration mirror or the rotating polygon mirror, which is the beam scanning function in the beam irradiation device 52A.

The present invention is not limited to the above-described embodiment, and can be modified in various ways without departing from the gist thereof. For example, in the above-described embodiment, the embodiment in which the strain 20 for magnetic domain control is applied and the groove 25 is formed by the same beam irradiation device 52A has been described, but the strain 20 for magnetic domain control has been described. The beam irradiation unit may be used independently of the case of applying the beam and the case of forming the groove 25.
Further, in the above-described embodiment, the strain 20 for controlling the magnetic zone extending in the width direction W intersecting the rolling direction D of the grain-oriented electrical steel sheet 40 by irradiating the surface of the grain-oriented electrical steel sheet 40 with a beam by itself. However, the grain-oriented electrical steel sheet 40 to which the strain 20 for controlling the magnetic zone is imparted is acquired from the outside, and the groove 25 is formed in the grain-oriented electrical steel sheet 40 thus acquired. You may. In that case, the distortion applying step (beam irradiation unit) can be eliminated.
Further, in the above-described embodiment, the groove 25 is formed directly above the bent portion R1 at the corner portion R of the grain-oriented electrical steel sheet 40, but the groove 25 may not be formed directly above the bent portion R1.
Further, in the above description, the method of applying the strain 20 for magnetic domain control using an example of applying the strain 20 for magnetic domain control using a beam such as a laser or an electron beam has been described, but the method of applying the strain 20 for magnetic domain control is limited to them. However, other known methods can also be used. For example, when applying the strain 20 for magnetic domain control, the strain 20 is applied by irradiating with plasma, or the surface of the grain-oriented electrical steel sheet 40 is scratched with a hard protrusion or shot peening is used to obtain a direction. It is also possible to apply or apply compressive stress to the electrical steel sheet 40.
Further, in the above description, the groove 25 is formed by using an example of forming the groove 25 by using a laser or an electron beam, but the method of forming the groove 25 is not limited to these, and other known methods. Can also be used. For example, when the groove 25 is formed, it can be formed by irradiating a beam other than a laser or an electron beam, etching, or mechanically pressing.
Further, a part or all of the above-described embodiments may be combined within a range that does not deviate from the gist of the present invention, or a part of the configuration may be omitted from one of the above-described embodiments. May be good.

10-wound iron core 20 Distortion for magnetic domain control 25 Groove 40 Directional electromagnetic steel plate 50 Steel plate supply part 52 Beam irradiation part 52A Beam irradiation device 54 Bending part 56 Assembling part R Square part R1 Bending part

Claims (7)

The strain for controlling the magnetic domain extending in the width direction intersecting the rolling direction is a wound iron core formed by individually bending a grain-oriented electrical steel sheet applied to the surface and assembling it into a wound shape. ,
A wound iron core in which a groove extending in the width direction is formed on the surface of the grain-oriented electrical steel sheet in a portion to be a bent portion in the bending process and a region in the vicinity thereof. The grooves are formed at intervals of 2 mm to 10 mm in the rolling direction.
The wound iron core according to claim 1, wherein the vicinity of the portion that becomes the bent portion in the bending process is in the range of 1 mm to 50 mm in the rolling direction, centering on the portion that becomes the bending portion in the bending process. A strain applying step of irradiating the surface of the grain-oriented electrical steel sheet with a beam to impart a strain for controlling a magnetic domain extending in a width direction intersecting the rolling direction of the grain-oriented electrical steel sheet.
A groove forming step of forming a groove extending in the width direction of the grain-oriented electrical steel sheet by irradiating the surface of the grain-oriented electrical steel sheet with a beam.
A bending step in which the grain-oriented electrical steel sheet to which strain for magnetic domain control is applied and a groove is formed is individually bent.
Assembling step of forming a wound iron core by assembling the bent magnetic steel sheet in a wound shape.
Have,
In the strain applying step, strain for controlling the magnetic domain is applied in a region other than the portion to be a bent portion in the bending process and its vicinity on the surface of the grain-oriented electrical steel sheet.
The groove forming step is a method for manufacturing a wound iron core, wherein the groove is formed in a portion of the surface of the grain-oriented electrical steel sheet that becomes a bent portion in the bending process and a region in the vicinity thereof. In the strain applying step and the groove forming step, the same beam irradiation device is used, and at least one of the power, the condensing shape, and the irradiation speed of the beam is changed to apply strain for controlling the magnetic domain. The method for manufacturing a wound iron core according to claim 3, wherein the process of switching between the step and the groove forming step is switched. By irradiating the surface with a beam, a grain-oriented electrical steel sheet with strain for controlling magnetic domains extending in the width direction intersecting the rolling direction is used.
A groove forming step of forming a groove extending in the width direction of the grain-oriented electrical steel sheet by irradiating the surface of the grain-oriented electrical steel sheet with a beam.
A bending step in which the grain-oriented electrical steel sheet to which strain for magnetic domain control is applied and a groove is formed is individually bent.
Assembling step of forming a wound iron core by assembling the bent magnetic steel sheet in a wound shape.
Have,
The groove forming step is a method for manufacturing a wound iron core, wherein the groove is formed only in a portion of the surface of the grain-oriented electrical steel sheet that becomes a bent portion in the bending process and a region in the vicinity thereof. By irradiating the surface of the grain-oriented electrical steel sheet with a beam, strain for controlling the magnetic zone extending in the width direction intersecting the rolling direction of the grain-oriented electrical steel sheet is applied, and the surface of the grain-oriented electrical steel sheet is irradiated with the beam. As a result, the beam irradiation unit that forms the groove extending in the width direction of the grain-oriented electrical steel sheet,
A bending portion that individually bends the grain-oriented electrical steel sheet to which strain for magnetic domain control is applied and a groove is formed, and
An assembling portion that forms a wound iron core by assembling the bent electromagnetic steel sheet into a wound shape.
Have,
The beam irradiation unit
On the surface of the grain-oriented electrical steel sheet, a strain for controlling the magnetic domain is applied in a region other than the portion to be a bent portion in the bending process and its vicinity.
An apparatus for manufacturing a wound iron core, which forms the groove in a portion of the surface of the grain-oriented electrical steel sheet that becomes a bent portion in the bending process and a region in the vicinity thereof. By irradiating the surface with a beam, a grain-oriented electrical steel sheet having a strain for controlling a magnetic zone extending in the width direction intersecting the rolling direction is used, and by irradiating the surface of the grain-oriented electrical steel sheet with a beam, the above-mentioned A beam irradiation portion that forms a groove extending in the width direction of the grain-oriented electrical steel sheet, and
A bending portion that individually bends the grain-oriented electrical steel sheet to which strain for magnetic domain control is applied and a groove is formed, and
An assembling portion that forms a wound iron core by assembling the bent-processed grain-oriented electrical steel sheet in a wound shape.
Have,
The beam irradiation unit
An apparatus for manufacturing a wound iron core, which forms the groove only in a portion of the surface of the grain-oriented electrical steel sheet that becomes a bent portion in the bending process and a region in the vicinity thereof.

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