JP2017204613A - Conductive steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive steel sheet capable of reducing classical eddy current loss.SOLUTION: The conductive steel sheet has a plurality of thin portions. Each of the plurality of thin portions is formed in a concave shape. The thin portion inhibits passage of a current generated by electromagnetic induction and generates an eddy current between adjacent thin portions when a magnetic flux passes through the conductive steel sheet.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive steel sheet that can reduce eddy current loss.

  Conventionally, by providing a groove extending in the plate width direction of a unidirectional electrical steel sheet, the magnetic domains are subdivided to reduce abnormal eddy current loss. Patent Document 1 discloses a unidirectional electrical steel sheet in which characteristics relating to abnormal eddy current loss are further improved by providing a plurality of line-shaped sub-grooves extending in the rolling direction starting from a main groove extending in the sheet width direction. Is disclosed.

Japanese Patent No. 4719319

  The unidirectional electrical steel sheet described in Patent Document 1 reduces abnormal eddy current loss due to domain wall motion, and reduces eddy current loss (classical eddy current loss) due to eddy current generated in a steel sheet as a conductor. It is not possible.

  This invention is made | formed in view of such a situation, The main objective is to provide the electroconductive steel plate which can reduce a classic eddy current loss.

  In order to solve the above-described problem, the conductive steel sheet according to one aspect of the present invention includes a plurality of thin portions each formed in a concave shape, and a thick portion formed between the adjacent thin portions, The thin-walled portion is configured to generate an eddy current in the thick-walled portion by inhibiting the passage of current generated by electromagnetic induction when placed in a magnetic field.

  In this aspect, a convex portion is formed in the thick-walled portion, and a concave portion is formed in the thin-walled portion, and when the two conductive steel plates are overlapped, the other concave portion of the one conductive steel plate You may be comprised so that the said convex part of the said electroconductive steel plate may be accommodated.

  Moreover, the said aspect WHEREIN: Each of the said thin part and the said thick part may be repeatedly provided continuously in any one of the width direction of the said electrically conductive steel plate, and the length direction.

  Moreover, the said aspect WHEREIN: The said thin part may be comprised so that bending is possible.

  Further, in the above aspect, each of the thin portion and the thick portion is configured to extend in a direction orthogonal to the continuously repeating direction when viewed from a direction facing the plane of the conductive steel plate. May be.

  Moreover, the said aspect WHEREIN: Each of the said thin part and the said thick part may be continuously provided repeatedly in both the width direction and the length direction of the said electrically conductive steel plate.

  Moreover, the said aspect WHEREIN: Each of the said thin part and the said thick part may be comprised so that a square may be made when it sees from the direction facing the plane of the said electrically conductive steel plate.

  Moreover, the said aspect WHEREIN: Each of the said thin part and the said thick part may be repeatedly provided continuously in each of the three directions which cross | intersect mutually parallel to the surface of the said electrically conductive steel plate.

  Further, in the above aspect, the thin portion is configured to form a triangle when viewed from a direction facing the plane of the conductive steel sheet, and the thick portion is viewed from a direction facing the plane. It may be configured to form an inverted triangle.

  According to the present invention, classical eddy current loss can be reduced.

FIG. 2 is a perspective view showing a configuration of a conductive steel plate according to Embodiment 1. 1 is a front view showing a configuration of a conductive steel plate according to Embodiment 1. FIG. The front view which shows a state when two electroconductive steel plates are piled up. The perspective view which shows a state when deforming a conductive steel plate. The perspective view which shows the conventional general electroconductive steel plate. Front sectional drawing for demonstrating the path | route of the eddy current which arises in the conductive steel plate shown in FIG. The perspective view which shows the case where two or more conductive steel plates with a small board width are arranged. Front sectional drawing for demonstrating the path | route of the eddy current which arises in the conductive steel plate shown in FIG. FIG. 3 is a front cross-sectional view for explaining a path of eddy current generated in the conductive steel plate according to the first embodiment. The figure which shows the analysis result of the eddy current in the conventional electroconductive steel plate. The figure which shows the analysis result of the eddy current in the electrically conductive steel plate concerning Embodiment 1. FIG. The graph which shows the result of an evaluation test. The perspective view which shows the structure of the electrically conductive steel plate which concerns on Embodiment 2. FIG. Side surface sectional drawing which shows the structure of the electrically conductive steel plate which concerns on Embodiment 2. FIG. Side surface sectional drawing which shows a state when two conductive steel plates are piled up. FIG. 6 is a front sectional view for explaining a path of eddy current generated in the conductive steel plate according to the second embodiment. FIG. 6 is a plan view showing a configuration of a conductive steel plate according to a third embodiment. Sectional drawing by the AA in FIG. Sectional drawing by the BB line in FIG. Sectional drawing by CC line in FIG. Sectional drawing by the DD line | wire in FIG. Sectional drawing which shows a state when two conductive steel plates are piled up. Sectional drawing for demonstrating the path | route of the eddy current which arises in the electrically conductive steel plate which concerns on Embodiment 4. FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
In the present embodiment, a conductive steel plate in which a thin portion and a thick portion extending in the plate width direction are repeatedly provided continuously in the rolling direction will be described. Here, the conductive steel plate refers to a steel plate having conductivity, and may be either a magnetic material or a non-magnetic material. The conductive steel sheet may be a soft magnetic electromagnetic steel sheet, and when it is an electromagnetic steel sheet, it may be a non-directional or directional magnetic steel sheet. In the following embodiments, a conductive steel plate that is not an electromagnetic steel plate will be described.

  FIG. 1 is a perspective view showing a configuration of a conductive steel plate according to the present embodiment, and FIG. 2 is a front view thereof. In the following description, the width direction of the conductive steel plate is referred to as the X direction, the longitudinal direction (rolling direction) of the conductive steel plate is referred to as the Y direction, and the thickness direction of the conductive steel plate is referred to as the Z direction.

  As shown in FIG. 1, the conductive steel plate 100 has a configuration in which a plurality of rhombus portions are arranged in the Y direction when viewed in the X direction. As shown in FIG. 2, the rhombus portion has a large thickness at the center portion in the Y direction, and the thickness decreases toward both sides in the Y direction. Adjacent rhombus portions are connected so that the opposite vertices of two rhombuses are connected. That is, the upper surface of the conductive steel plate 100 is provided with inverted triangular concave portions 102 arranged at equal intervals in the Y direction as viewed in the X direction, and the triangular concave portions 102 are provided on the lower surface thereof in the Y direction when viewed in the X direction. Are arranged at regular intervals. The concave portions 102 provided on each of the upper surface and the lower surface are provided at the same position in the Y direction so that the apexes face each other in the Z direction, and the region sandwiched between the two apexes is the thin portion 101. is there.

  The thin portion 101 extends in the X direction over the entire width of the conductive steel plate 100. Further, the thin portion 101 is repeatedly provided continuously at equal intervals in the Y direction over the entire length of the conductive steel plate 100.

  In addition, a convex portion 103 protruding in a triangular shape when viewed in the X direction is formed between two concave portions 102 adjacent in the Y direction. The shape of the convex portion 103 is adapted to the shape of the concave portion 102. That is, as shown in FIG. 2, the depth D <b> 1 of the concave portion 102 is also the height of the convex portion 103. The angle of the vertex of the triangle of the concave portion 102 is the same as the angle of the vertex of the triangle of the convex portion 103.

  A diamond-shaped portion between two adjacent thin portions 101 is a thick portion 104 that is thicker than the thin portion 101. That is, the concave portion 102 is formed in the thin portion 101 and the convex portion 103 is formed in the thick portion 104. The thick portion 104 extends in the X direction over the entire width of the conductive steel plate 100. Further, the thick portion 104 is repeatedly provided continuously at equal intervals in the Y direction over the entire length of the conductive steel plate 100.

  In the conductive steel plate 100 as described above, the interval at which the concave portions 102 are arranged is the same as the interval at which the convex portions 103 are arranged. For this reason, a plurality of conductive steel plates 100 can be used in an overlapping manner. FIG. 3 is a front view showing a state when two conductive steel plates 100a and 100b are stacked. As shown in FIG. 3, the convex part 103b of the other electroconductive steel plate 100b is accommodated in the recessed part 102a of one electroconductive steel plate 100a. Moreover, the convex part 103a of the electroconductive steel plate 100a is accommodated in the recessed part 102b of the electroconductive steel plate 100b. The shape of the concave portions 102a and 102b and the shape of the convex portions 103a and 103b are matched, and can be overlapped with almost no gap. Thereby, even if it piles up several electroconductive steel plates 100a and 100b, there is no location which has a large gap and each electroconductive steel plates 100a and 100b can be stuck mutually.

  Further, the conductive steel plate 100 can be easily bent at the thin portion 101. FIG. 4 is a perspective view showing a state when the conductive steel plate 100 is deformed. As shown in FIG. 4, the conductive steel plate 100 can be deformed by bending at each thin portion 101. For this reason, the conductive steel plate 100 can be easily deformed into various shapes.

Next, eddy current loss in the conductive steel plate 100 will be described. FIG. 5 is a perspective view showing a conventional general conductive steel sheet, and FIG. 6 is a front sectional view showing an example of eddy current generated in the conductive steel sheet. As shown in FIG. 5, consider a case where a magnetic flux in the Y direction is incident on a general conductive steel sheet 150. In this case, electromagnetic induction occurs due to the change in magnetic flux, and an eddy current as shown by an arrow in FIG. At this time, assuming that the magnetic flux uniformly enters the front surface of the conductive steel plate 150 and passes through the plate, the time average value P _ave of the generated loss is expressed by the following equation.

Here, when the plate thickness a is sufficiently smaller than the plate width b, the following equation holds.
From equation (2), the eddy current loss per volume V is proportional to the square of the plate thickness a.

Next, consider a case where a plurality of conductive steel plates having a small plate width are arranged. FIG. 7 is a perspective view showing a case where a plurality of conductive steel plates having a small plate width are arranged. In the example shown in FIG. 7, the plate width b ′ of one conductive steel plate is substantially the same as the plate thickness a. The time average value P _ave of loss at this time is expressed by the following equation.

  As shown in the equation (3), in this case, the loss per volume is halved. This is because the voltage induced by electromagnetic induction does not change, but the resistance value changes by dividing the current path.

FIG. 8 is a front sectional view for explaining a path of eddy current generated in the example shown in FIG. As shown in FIG. 8, an eddy current is generated in each conductive steel plate 160. The current path l at this time approximates to 4a as shown in the following equation.
In contrast, in the example shown in FIG. 6, the current path l approximates to 2b as shown in the following equation.

As described above, by arranging the conductive steel plates 160 having a small cross-sectional area, the current path l is doubled and the resistance value is increased. For this reason, the induced current is reduced and the Joule loss (RI ² ) is halved.

  Here, consider the conductive steel sheet 100 according to the present embodiment. FIG. 9 is a front cross-sectional view for explaining a path of eddy current generated in the conductive steel plate according to the present embodiment. The conductive steel plate 100 is provided with thin portions 101 at a plurality of locations. Since the thin portion 101 has a small volume, it has a high resistance value and obstructs the passage of current. For this reason, it can be considered that the thick part 104 divided by each thin part 101 corresponds to a conductive steel sheet having a small cross-sectional area as described above. Therefore, in the conductive steel plate 100, an eddy current is generated in each thick portion 104 as shown in FIG. Therefore, eddy current loss (classical eddy current loss) can be reduced as compared with the prior art.

(Evaluation test)
FEM analysis was performed on the conventional general conductive steel plate 150 and the conductive steel plate 100 according to the present embodiment, and the path of eddy current was analyzed. FIG. 10A is a diagram showing an analysis result of eddy current in a conventional conductive steel plate, and FIG. 10B is a diagram showing an analysis result of eddy current in the conductive steel plate according to the present embodiment. As shown in FIG. 10A, in the conventional conductive steel sheet 150, eddy currents are uniformly generated inside the cross section. In contrast, in the conductive steel plate 100 according to the present embodiment, as shown in FIG. 10B, it can be seen that eddy currents circulate in each thick portion 104.

  FIG. 11 is a graph showing the results of this evaluation test. In FIG. 11, the vertical axis represents the magnitude of eddy current loss, and the horizontal axis represents the frequency of eddy current. Moreover, in FIG. 11, the broken line graph shows the result of the conventional conductive steel plate 150, and the solid line graph shows the result of the conductive steel plate 100 according to the present embodiment. In this test, the loss of the conventional conductive steel plate 150 and the conductive steel plate 100 according to the present embodiment was examined by changing the frequency of the eddy current. As shown in FIG. 11, in the conventional conductive steel sheet 150, the loss greatly increases as the frequency increases. On the other hand, in the conductive steel plate 100 according to the present embodiment, the loss increases as the frequency increases, but the increase rate is suppressed to be very low compared to the conventional conductive steel plate 150. I understand.

(Embodiment 2)
In the present embodiment, a description will be given of a conductive steel plate in which a rectangular thin portion and a thick portion are repeatedly provided in the rolling direction and the plate width direction in plan view.

  FIG. 12 is a perspective view showing the configuration of the conductive steel plate according to the present embodiment. As shown in FIG. 12, the conductive steel plate 200 has a configuration in which a plurality of square portions are arranged in the X and Y directions as viewed in the Z direction (plan view). Some of the quadrangular portions are concave portions 202, and the other quadrangular portions are convex portions 203.

  The concave portions 202 and the convex portions 203 are arranged in a checkered pattern. That is, the convex portion 203 is adjacent to each of the four directions of the concave portion 202, and the concave portion 202 is adjacent to each of the four directions of the convex portion 203. The convex portion 203 is formed by being surrounded by four adjacent concave portions 202, and the concave portion 202 is formed by being surrounded by four adjacent convex portions 203.

  The recess 202 has a square shape in plan view. Further, the convex portion 203 has a shape corresponding to the concave portion 202, and similarly has a square shape in a plan view. The length of one side of the square of the convex portion 203 is substantially the same as the length of one side of the square of the concave portion 202. More precisely, the length of one side of the square of the convex portion 203 is slightly smaller than the length of one side of the square of the concave portion 202. Thereby, the convex part 203 can be accommodated in the concave part 202.

  FIG. 13 is a side sectional view showing the configuration of the conductive steel plate according to the present embodiment. As shown in FIG. 13, the depth D <b> 2 of the concave portion 202 is also the height of the convex portion 203. As described above, the shape of the concave portion 202 matches the shape of the convex portion 203.

  Moreover, as shown in FIG. 13, the both sides of the conductive steel plate 200 are provided with square or rectangular recesses 202 arranged at equal intervals in the Y direction when viewed in the X direction. Similarly, a plurality of such recesses 202 are provided side by side in the X direction (see FIG. 12). The concave portions 202 provided on the upper surface and the lower surface are provided at the same position in the X and Y directions, and a region sandwiched between the two concave portions 202 facing in the Z direction is the thin portion 201.

  Further, the convex portions 203 are arranged at equal intervals in the X and Y directions on both surfaces of the conductive steel plate 200. The convex portions 203 provided on the upper surface and the lower surface are provided at the same position in the X and Y directions, and a portion where the two convex portions 203 facing each other in the Z direction overlap is a thick portion 204. That is, the concave portion 202 is formed in the thin portion 201 and the convex portion 203 is formed in the thick portion 204. The thickness t2 of the thick portion 204 is sufficiently larger than the thickness T2 of the thin portion 201.

  In the conductive steel plate 200 as described above, the direction and interval in which the concave portions 202 are arranged are the same as the direction and interval in which the convex portions 203 are arranged. For this reason, a plurality of the conductive materials 200 can be used in an overlapping manner. FIG. 14 is a side cross-sectional view showing a state when two conductive steel plates 200a and 200b are overlapped. As shown in FIG. 14, the convex part 203b of the other conductive steel plate 200b is accommodated in the concave part 202a of one conductive steel sheet 200a. Moreover, the convex part 203a of the electroconductive steel plate 200a is accommodated in the recessed part 202b of the electroconductive steel plate 200b. The shape of the recesses 202a and 202b and the shape of the projections 203a and 203b match, and can be overlapped with almost no gap. Thereby, even if it piles up several electroconductive steel plates 200a and 200b, there is no location where a big gap is opened, and each electroconductive steel plates 200a and 200b can be stuck mutually.

  FIG. 15 is a front sectional view for explaining a path of eddy current generated in the conductive steel sheet according to the present embodiment. The conductive steel plate 200 is provided with thin portions 201 at a plurality of locations. Since the thin portion 201 has a small volume, it has a high resistance value and obstructs the passage of current. For this reason, as shown in FIG. 15, an eddy current is generated in the conductive steel plate 200 in the thick portion 204 surrounded by the thin portion 201. Therefore, eddy current loss (classical eddy current loss) can be reduced as compared with the prior art.

(Embodiment 3)
In the present embodiment, a description will be given of a conductive steel plate that is continuously and repeatedly provided in each of three directions in which triangular thin portions intersect each other in plan view.

  FIG. 16 is a plan view showing the configuration of the conductive steel plate according to the present embodiment. In FIG. 16, what is indicated by a broken line is a reference plane. Further, the hatched portion is a concave portion 302 that is recessed from the reference surface, and the non-hatched portion is a convex portion 303 that protrudes from the reference surface. As shown in FIG. 16, the conductive steel sheet 300 has a plurality of concave portions 302 and convex portions 303 in a first direction (X direction), a second direction, and a third direction in the figure when viewed in the Z direction (plan view). It has a configuration in which each direction is arranged alternately.

  The concave portions 302 and the convex portions 303 are arranged in a triangular lattice shape in plan view. The convex portion 303 is adjacent to each of the first to third directions of the concave portion 302, and the concave portion 302 is adjacent to each of the first to third directions of the convex portion 303. The convex portion 303 is formed by being surrounded by three adjacent concave portions 302, and the concave portion 302 is formed by being surrounded by three adjacent convex portions 303.

  The recess 302 has an equilateral triangle in plan view. Moreover, the convex part 303 is a shape corresponding to the concave part 302, and has formed the inverted equilateral triangle in planar view. The adjacent concave portion 302 and the convex portion 303 share one side of each triangle, and the length of one side of the inverted regular triangle of the convex portion 303 is the same as the length of one side of the regular triangle of the concave portion 302.

  17A is a cross-sectional view taken along line AA in FIG. 16, FIG. 17B is a cross-sectional view taken along line BB, FIG. 17C is a cross-sectional view taken along line CC, and FIG. It is sectional drawing by -D line. The shape of the concave portion 302 is a regular triangular pyramid, and the shape of the convex portion 303 is also a regular triangular pyramid. The length of each side of the concave portion 302 and the length of each side of the convex portion 303 are the same, and both equilateral triangular pyramids are congruent. For this reason, the depth D3 of the concave portion 302 from the reference surface is substantially the same as the height H3 of the convex portion 303 from the reference surface. Thus, the shape of the concave portion 302 matches the shape of the convex portion 303, and the convex portion 303 can be accommodated in the concave portion 302.

  Moreover, the recessed part 302 is provided in the same position of each both surfaces of the conductive steel plate 300 so that it may oppose. That is, on each of both surfaces of the conductive steel sheet 300, the recesses 302 are provided at equal intervals in each of the first to third directions (see FIG. 16). The recesses 302 provided on each of the upper surface and the lower surface are provided at the same position in the X and Y directions with their apexes facing the Z direction (see FIG. 17A). Of the region sandwiched between the two concave portions 302 facing in the Z direction, the portion sandwiched between two sides facing in the Z direction has a particularly small thickness. For this reason, this part is made into the thin part 301 (refer FIG. 16, FIG. 17A thru | or FIG. 17C).

  Similarly, the convex part 303 is provided in the same position of both surfaces of the electrically conductive steel plate 300 so that it may oppose. That is, on each of both surfaces of the conductive steel sheet 300, the convex portions 303 are also provided at equal intervals in each of the three directions of the first to third directions (see FIG. 16). A portion where two convex portions 303 facing each other in the Z direction overlap is a thick portion 304. That is, the concave portion 302 is formed in the thin portion 301 and the convex portion 303 is formed in the thick portion 304. The thickness of the thick part 304 is sufficiently larger than the thickness of the thin part 301.

  In the conductive steel sheet 300 as described above, the concave portion 302 is a triangular pyramid that forms an equilateral triangle when viewed in the Z direction, and the convex portion 303 is a triangular pyramid that forms an inverted regular triangle when viewed in the Z direction. Therefore, in the two conductive steel plates 300, when the direction of one conductive steel plate 300 is not changed and the direction of the other conductive steel plate 300 is reversed in the X direction, the shape of the concave portion 302 of the one conductive steel plate 300 is obtained. And the shape of the convex part 303 of the other electroconductive steel plate 300 corresponds. Further, the direction and interval in which the concave portions 302 are arranged in one conductive steel plate 300 is the same as the direction and interval in which the convex portions 303 are arranged in the other conductive steel plate 300. Similarly, the shape, arrangement direction, and interval of the convex portions 303 in one conductive steel sheet 300 match the shape, arrangement direction, and interval of the concave portions 302 in the other conductive steel sheet 300. For this reason, two electroconductive 300 can be piled up by inverting the direction of the other electroconductive steel plate 300 to a X direction, without changing the direction of one electroconductive steel plate 300. FIG. FIG. 18 is a cross-sectional view showing a state when two conductive steel plates 300a and 300b are stacked. In FIG. 18, the cross section by the AA line in FIG. 16 is shown. As shown in FIG. 18, the convex part 303b of the other electroconductive steel plate 300b is accommodated in the recessed part 302a of one electroconductive steel plate 300a. Further, the convex portion 303a of the conductive steel plate 300a is accommodated in the concave portion 302b of the conductive steel plate 300b. The shape of the concave portions 302a and 302b and the shape of the convex portions 303a and 303b are coincident with each other and can be overlapped with almost no gap. Thereby, even if it piles up several electroconductive steel plates 300a and 300b, there is no place which has a large clearance gap, and each electroconductive steel plates 300a and 300b can be stuck mutually.

  FIG. 19 is a cross-sectional view for explaining a path of eddy current generated in the conductive steel sheet according to the present embodiment. In FIG. 19, the cross section by the AA line in FIG. 16 is shown. The conductive steel plate 300 is provided with thin portions 301 at a plurality of locations. Since the thin portion 301 has a small volume, it has a high resistance value and obstructs the passage of current. For this reason, as shown in FIG. 19, an eddy current is generated in the conductive steel sheet 300 in the thick part 304 surrounded by the thin part 301. Therefore, eddy current loss (classical eddy current loss) can be reduced as compared with the prior art.

  The conductive steel sheet of the present invention is useful as a conductive steel sheet that can reduce eddy current loss.

100, 200, 300 Conductive steel plate 101, 201, 301 Thin part 102, 202, 302 Concave part 103, 203, 303 Convex part 104, 204, 304 Thick part

Claims (9)

A plurality of thin portions each formed in a concave shape;
A thick portion formed between the adjacent thin portions;
With
When placed in a magnetic field, the thin-walled portion is configured to generate an eddy current in the thick-walled portion by inhibiting the passage of current generated by electromagnetic induction.
Conductive steel plate. A convex portion is formed in the thick portion, and a concave portion is formed in the thin portion,
When the two conductive steel plates are stacked, the concave portion of one of the conductive steel plates is configured to accommodate the convex portion of the other conductive steel plate,
The conductive steel sheet according to claim 1. Each of the thin-walled portion and the thick-walled portion is repeatedly provided continuously in either one of the width direction and the length direction of the conductive steel plate,
The conductive steel sheet according to claim 1 or 2. The thin portion is configured to be bendable,
The conductive steel sheet according to claim 3. Each of the thin part and the thick part is configured to extend in a direction orthogonal to the continuously repeating direction when viewed from a direction facing the plane of the conductive steel plate.
The conductive steel sheet according to claim 3 or 4. Each of the thin-walled portion and the thick-walled portion is repeatedly provided continuously in both the width direction and the length direction of the conductive steel plate,
The conductive steel sheet according to claim 1 or 2. Each of the thin part and the thick part is configured to form a quadrangle when viewed from the direction facing the plane of the conductive steel plate,
The conductive steel sheet according to claim 6. Each of the thin-walled portion and the thick-walled portion is provided repeatedly in succession in each of three directions parallel to the surface of the conductive steel sheet and intersecting each other.
The conductive steel sheet according to claim 1 or 2. The thin-walled portion is configured to form a triangle when viewed from the direction facing the plane of the conductive steel plate,
The thick portion is configured to form an inverted triangle when viewed from the direction facing the plane.
The conductive steel sheet according to claim 8.