WO2010013501A1 - Cylindrical iron core, stationary induction apparatus and induction heat-generating roller device - Google Patents

Abstract

Provided is a cylindrical iron core, in which a gap in the whole section of a stationary electromagnetic induction-type circular core of a transformer or a reactor can be reduced and limiting iron loss due to leakage flux on the outer circumferential surface can be suppressed. The cylindrical iron core comprises a plurality of core blocks (2) formed by concentrically laminating cylindrical core elements (2A, 2B, 2C) which are formed by laminating a plurality of magnetic steel plates (21), each of which is provided with a curved portion (211) having a curved section in the width direction, while shifting from each other in the width direction.

Description

Cylindrical iron core, stationary induction device and induction heating roller device

The present invention relates to a circular iron core (cylindrical iron core) used for stationary induction equipment such as a transformer or a reactor and induction heating equipment such as an induction heating roller device.

In static induction devices such as transformers and reactors, the loss of the iron core, which is a magnetic path, is a cause of reduced efficiency and heat generation of the device, and its reduction is a major issue. In particular, the eddy current loss of the iron core due to the leakage magnetic flux occupies a large ratio, and the iron core generates heat due to the eddy current, thereby reducing the efficiency of the device. Moreover, it becomes a factor which causes the efficiency fall and insulation fall of the induction coil currently wound by this. It is known that the magnitude of the eddy current increases in proportion to the square of the width or thickness of the magnetic steel sheet in which the magnetic flux enters vertically.

In this static induction device, the iron core may be formed into a columnar shape for reasons such as shortening the length of the coil conductor wound around the iron core. At this time, as an iron core for stationary induction equipment, a laminated iron core (see Patent Document 1) configured by laminating flat magnetic steel plates having different width dimensions to form a columnar shape, laminating a flat magnetic steel plate, and winding this round There is a wound iron core (refer to Patent Document 2) configured in a columnar shape, and a radial iron core (refer to Patent Document 3) configured in a cylindrical shape by laminating flat magnetic steel plates radially. In these iron cores, a magnetic gap may be provided between the iron cores in order to obtain a desired reactance by setting an appropriate magnetic flux density (see Patent Document 2).

However, in the stacked iron core as shown in Patent Document 1, it is necessary to increase the types of magnetic steel sheets having different width dimensions in order to approach a perfect circle, which increases the manufacturing cost and makes the assembly work complicated. There is a problem such as. In addition, when a magnetic gap is provided, in the iron core in the vicinity of the gap, the leakage magnetic flux penetrating in the radial direction and discharged to the outside increases. However, this leakage magnetic flux causes an eddy current, and the iron core generates heat. There is a problem of end.

Moreover, in the wound iron core as shown in Patent Document 2, the entire flat portion of the steel plate provided on the outermost periphery is exposed, and the maximum value of eddy current generated by the penetration of the leakage magnetic flux is large, and the iron loss increases. There is a problem of end up. In addition, this problem becomes significant when a magnetic gap is provided.

Furthermore, in the radial iron core as shown in Patent Document 3, the leakage magnetic flux passes through the end face of the steel sheet, and the eddy current can be reduced and the heat generation amount of the iron core can be reduced, but the narrow magnetic core The work of arranging the steel plates radially along a certain circumference is extremely troublesome. Even if the inner ends of the magnetic steel plates are arranged closely, a gap is formed between the outer ends of the adjacent magnetic steel plates. Therefore, in order to improve the space factor of the iron core, it is necessary to work such as filling the gap by inserting another narrow magnetic steel plate in the gap.

By the way, although it is not used for stationary induction equipment, as an iron core used for induction heat generation equipment such as an induction heat generation roller device, as shown in Patent Document 4, a narrow-width section having a curved portion whose cross-section in the width direction forms a curved shape. A cylindrical iron core formed by stacking magnetic steel plates while being shifted in the width direction is considered by the present applicant. According to this, generation | occurrence | production of the eddy current by a leakage magnetic flux penetrating a magnetic steel plate can be made small, and it becomes possible to reduce the emitted-heat amount of an iron core.

This cylindrical iron core has the problem that the effective cross-sectional area that becomes a magnetic path is small because the magnetic steel sheets with a narrow width are stacked. From the viewpoint of improving the space factor, the width dimension of the magnetic steel sheet is simply set. It is possible to enlarge it. However, if the width dimension is simply increased, the outer diameter becomes larger, so that there is a problem that the use is limited. In order to reduce the outer diameter, it is conceivable to provide the magnetic steel sheet so as to be inclined as much as possible with respect to the radial direction. However, in this case, the area of the planar portion exposed to the outside of the magnetic steel sheet increases. Therefore, there is a problem that the generation of eddy currents cannot be prevented.
Japanese Utility Model Publication No. 62-30317 JP 2001-237124 A JP-A-5-109546 JP 2000-311777 A JP-A-9-232165 Registered Utility Model No. 2532986

Accordingly, the present invention has been made to solve the above-described problems all at once, and suppresses deterioration of the magnetic properties of the iron core such as iron loss as much as possible by improving the space factor and reducing eddy currents. This is the main desired issue.

That is, the iron core for a stationary induction device according to the present invention has a plurality of cylindrical core elements formed by stacking a plurality of magnetic steel plates having a curved portion whose cross section in the width direction forms a curved shape, shifted in the width direction, and concentrically formed. It is characterized by being laminated.
As a concrete embodiment, the cylindrical core element is curved with a constant curvature in the radial direction of the circular diameter, and a plurality of magnetic steel plates with a quarter width or less of the diameter with respect to the radial direction are stacked. It is desirable to be formed. If this is the case, the magnetic steel sheet has a width equal to or less than ¼ of the diameter in the radial direction. Therefore, the cylindrical iron core elements are concentrically arranged in the radial direction sequentially, so that the cross-sectional area of the curved magnetic steel sheet is increased. You can easily make a large round iron core.

Thus, according to the present invention, the core block is formed by laminating a plurality of cylindrical core elements on concentric circles, and the space in the entire cross section of the circular core can be reduced to improve the space factor. And iron loss can be reduced.
Further, the iron core for static induction equipment according to the present invention is a concentric circle of a plurality of cylindrical core elements formed by stacking a plurality of magnetic steel plates having a curved portion whose cross section in the width direction forms a curved shape, shifted in the width direction. The effect is increased in a method of use having a configuration in which a plurality of core blocks formed by laminating in a shape and a magnetic gap provided between the core blocks are provided. If this is the case, the gap member can increase or decrease the magnetic resistance in the magnetic path to obtain a desired reactance, and when the magnetic resistance is increased, the magnetic flux amount of the leakage magnetic flux penetrating in the radial direction increases. The leakage magnetic flux equivalently passes along the width direction of the magnetic steel plate provided substantially radially, and eddy current can be reduced. Furthermore, simplification of manufacturing and reduction of manufacturing cost can be realized by the configuration in which the magnetic gap is formed between the iron core blocks formed by shifting and stacking the magnetic steel plates.

Further, in order to simplify the formation of the magnetic gap and further facilitate the assembly of the iron core for stationary induction equipment, the magnetic gap is formed by sandwiching a gap member made of a non-magnetic material between the iron core blocks. It is desirable that

In order to reduce the maximum eddy current value as much as possible, the length in the width direction of the externally exposed portion on the laminated side surface of the magnetic steel sheet constituting the cylindrical core element provided on the radially outermost side of the core block is It is desirable that the thickness of the magnetic steel plate be equal to or less than the plate thickness.

As a concrete embodiment for setting the width direction length s of the externally exposed portion to be equal to or less than the plate thickness t of the magnetic steel plate, the inner diameter Φ of the cylindrical core element provided on the outermost side in the radial direction of the core block _A , the outer diameter Φ _B , and the thickness t of the magnetic steel sheet are

(Where α is the inclination angle of the magnetic steel sheet with respect to the radial direction of the inner circle of the cylindrical iron core element, and θ ′ is the central angle formed between the angle of the radially innermost end of the adjacent magnetic steel sheet and the circle center. Note that the unit of the trigonometric function is radians).

The tilt angle α of the magnetic steel sheet when the center angle θ ′ is equal to the center angle θ ₀ when the tilt angle of the magnetic steel sheet is zero is θ _X ,

When the inclination angle α of the magnetic steel sheet is θ _X or less,

When the inclination angle α of the magnetic steel sheet is larger than θ _X , the central angle θ ′ satisfying the above (Equation 1) is used.

It is to make a relationship.

Thus, according to the present invention, it is possible to suppress the deterioration of the magnetic properties of the iron core such as iron loss as much as possible by improving the space factor and reducing the eddy current.

It is a perspective view of the iron core for static induction equipment concerning one embodiment of the present invention. It is a top view of the iron core for stationary induction equipment of the embodiment. It is sectional drawing which shows the magnetic steel plate of the embodiment. It is a figure which shows the relationship between the plate | board thickness of an external exposure part and a magnetic steel plate. It is an enlarged schematic diagram ((theta) _21a = 0) which shows the width direction inner diameter side edge part of a magnetic steel plate. It is a figure which shows the distance of the outside angle ac when the width direction length of an external exposure part and the board thickness of a magnetic steel plate are made the same. It is an expansion schematic diagram (0 <(theta) _21a ) which shows the width direction inner diameter side edge part of a magnetic steel plate. It is a figure which shows a simulation result. It is a figure which shows a simulation result. It is a figure for explaining derivation of angle theta _X. It is sectional drawing which shows the modification of a magnetic steel plate. It is a typical block diagram of the induction heating roller apparatus using the cylindrical iron core of 2nd Embodiment. It is sectional drawing of the cylindrical iron core of the same embodiment. It is sectional drawing which shows the magnetic steel plate of the embodiment. It is a figure which shows the relationship between the plate | board thickness of an external exposure part and a magnetic steel plate. It is a typical block diagram of the reactor using the cylindrical iron core of 2nd Embodiment. It is a typical block diagram of a cantilever induction heating roller device. It is sectional drawing which shows the structure of the conventional stacked iron core.

<First Embodiment>
Next, an embodiment of the iron core 1 for stationary induction equipment according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an outline of the configuration of the stationary induction device core 1 according to the present embodiment, and FIG. 2 is a plan view of the stationary induction device core 1.

A stationary induction device iron core 1 according to the present embodiment is a circular iron core used in, for example, a reactor or a transformer, and as shown in FIG. 1, a plurality of iron core blocks 2 and a magnetic gap provided between the iron core blocks 2. 3.

As shown in FIG. 2, the iron core block 2 is formed by laminating a plurality (three in this embodiment) of cylindrical iron core elements 2A, 2B, and 2C in a concentric radial direction. The cylindrical core elements 2A, 2B, 2C adjacent in the radial direction are provided in contact with each other. That is, the outer diameter of one adjacent cylindrical core element 2A, 2B, 2C and the inner diameter of the other adjacent cylindrical core element 2A, 2B, 2C are substantially the same. Specifically, among the three cylindrical core elements 2A, 2B, and 2C, the core element provided on the inner diameter side is the first core element 2A, and the core element provided in the middle is the second core element 2B. When the core element provided on the outer diameter side is the third core element 2C, for example, the outer diameter of the first core element 2A and the inner diameter of the second core element 2B are substantially the same. An insulating layer (not shown) is provided between the cylindrical core elements 2A, 2B, 2C.

As shown in FIG. 2, the cylindrical core elements 2 </ b> A, 2 </ b> B, and 2 </ b> C are formed in a cylindrical shape by stacking a plurality of magnetic steel plates 21 while being shifted in the width direction.

The magnetic steel plate 21 has a long shape, and has a curved portion 211 having a curved cross section in the width direction as shown in FIG. The magnetic steel plate 21 is formed of, for example, a silicon steel plate having an insulating film on its surface, and its thickness is, for example, about 0.3 mm.

The curved portion 211 may be curved with a constant curvature throughout, or may be curved while the curvature continuously changes. For example, an involute shape using a part of an involute curve, a partial arc A shape or a partial ellipse shape is conceivable.

Then, the magnetic steel plates 21 are shifted in the width direction so that the convex portions formed by the curved portions 211 of the other magnetic steel plates 21 are fitted into the concave portions formed by the curved portions 211 of the magnetic steel plates 21. Then, a large number of magnetic steel plates 21 having the same shape are overlapped. At this time, the width direction end portions 21 a and 21 b of the magnetic steel plate 21 are in contact with the concave side surface or the convex side surface of the adjacent magnetic steel plate 21. In this way, cylindrical core elements 2A, 2B, 2C having a cylindrical shape are formed.

The magnetic gap 3 is formed by sandwiching a gap member made of a non-magnetic material between the core blocks 2 so that the core blocks 2 are substantially coaxial. The gap member is made of a non-magnetic material such as aluminum, ceramic, or glass, and may have a flat plate shape or a column shape. In the present embodiment, the iron core block 2 has an annular shape substantially the same shape as in plan view.

Next, the manufacturing method of the iron core 1 for static induction equipment of this embodiment is demonstrated.

A columnar member or a cylindrical member (hereinafter referred to as a columnar member or the like) having a predetermined outer diameter is prepared. The first iron core elements 2A are formed by being sequentially stacked along. Then, the first iron core element 2A is subjected to strain relief annealing and then fixed and insulated with a varnish or an insulator. Next, the width direction inner diameter side end 21a of the magnetic steel plate 21 is brought into contact with the outer peripheral surface of the first iron core element 2A subjected to fixing and insulation treatment, and along the outer peripheral surface of the first iron core element 2A. Then, the second core element 2B is formed by sequentially overlapping. While maintaining this shape, the first core element 2A, the cylindrical member, and the like are extracted from the second core element 2B, and the second core element 2B is strain-relieved and annealed. The second core element 2B is stacked along the outer peripheral surface of the first core element 2A. Then, by fixing and insulating with a varnish or an insulator, a two-layer iron core is formed by the first iron core element 2A and the second iron core element 2B. Furthermore, in the case of forming a multilayer, the core block 2 having an arbitrary number of layers can be formed by repeatedly performing the above process on the outer peripheral surface of the second core element 2B. The core 1 for stationary induction equipment is formed by stacking and fixing the core blocks 2 so as to be substantially coaxial with a gap member interposed between the core blocks 2 thus formed.

The obtained iron core 1 for a static induction device has a structure in which the magnetic steel plates 21 constituting the same are radially arranged in an equivalent manner. Even if a coil is wound around the outer periphery of the iron core 1 for the static induction device, a short circuit current is obtained. The leakage magnetic flux passes through the magnetic steel plate 21 along the width direction like the radial iron core, and does not pass through the magnetic steel plate in the thickness direction. Thereby, generation | occurrence | production of the eddy current by a leakage magnetic flux is suppressed. Further, since the cross section of the iron core is almost a perfect circle, the length of the coil conductor to be wound can be further shortened, and resource saving can be achieved.

Thus, as shown in the partially enlarged view of FIG. 4, the iron core 1 for stationary induction equipment of the present embodiment is a cylindrical core element (third core element) 2C provided on the outermost side in the radial direction of the core block 2. The magnetic steel plates 21 are laminated such that the width direction length s of the externally exposed portion 21x on the side surface of the magnetic steel plate 21 constituting the magnetic sheet 21 is equal to or less than the thickness t of the magnetic steel plate 21. That is, if the thickness t of the magnetic steel plate 21 is 0.3 mm, the length s in the width direction of the externally exposed portion 21x is set to 0.3 mm or less.

The laminated side surface of the magnetic steel plate 21 is the convex side surface 21n of the curved portion 211 among the side surfaces 21m and 21n facing the adjacent magnetic steel plate 21. And in this lamination | stacking side surface, the surface formed in the outer side rather than the width direction outer-diameter side edge part 21b of the magnetic steel plate 21 to contact is the external exposed part 21x.

Furthermore, as shown in FIG. 3, the width direction inner diameter side end portion 21a of the magnetic steel plate 21 has an inclination of the center line of the width direction inner diameter side end portion 21a with respect to the radial direction of the inner circle of the third core element 2C. _{So as} to have an inclination angle θ _21a . That is, the width direction inner diameter side end portion 21a of the magnetic steel plate 21 is provided so as to come into contact with the position of the plate thickness t or less from the width direction inner diameter side end portion 21a of the adjacent magnetic steel plate 21 toward the outer diameter direction. .

The third core element 2C of the present embodiment has an inner diameter Φ _A , an outer diameter Φ _{B of} the third core element 2C, and a thickness t of the magnetic steel sheet 21.

(Where α is the inclination angle θ _21a of the magnetic steel sheet 21 with respect to the radial direction of the inner circle of the third core element 2C, and θ ′ is the angle and circle of the radially innermost end of the adjacent magnetic steel sheet 21 The center angle θ ′ is the center angle θ ₀ when the inclination angle θ _21a of the magnetic steel sheet 21 is zero in the unit of trigonometric function in radians (rad). and an inclined angle α (= θ _21a) a theta _X of the magnetic steel plates 21 when equal, if: the inclination angle alpha is theta _X of the magnetic steel plates 21,

If the inclination angle α of the magnetic steel plates 21 is greater than the theta _X is using said center angle theta 'satisfying (Equation 1)

It is configured so that

As shown in FIG. 4, the relational expression (Expression 2) and the relational expression (Expression 3) are such that the width direction length s of the externally exposed portion 21x and the thickness t of the magnetic steel plate 21 satisfy s ≦ t. It shows a third core element 2C inner diameter [Phi _a and outer diameter [Phi _B relationship. Here, the inner diameter [Phi _A third core element 2C, the diameter of a circle inscribed in the width direction of the inner diameter side end portion 21a of the magnetic steel plates 21, and the outer diameter [Phi _B of the third core element 2C The diameter of a circle circumscribing the end portion 21b in the width direction outer diameter side of each magnetic steel plate 21 (see FIG. 2).

Widthwise inner diameter side end portion 21a of the magnetic steel plates 21 for simplicity, the tilt angle theta _21a of the center line of the third is perpendicular to the inner diameter [Phi _A of the core element 2C (the width direction inner diameter side end portion 21a is zero (Θ _21a = 0)) is shown in FIG. At this time, the center line of the straight line and the magnetic steel plates 21 connecting the corners and circle center O of the widthwise inner diameter side end portion 21a of the magnetic steel plates 21 (which is regarded as a straight line.) Angle between the theta _0/2 (rad) Then, the following relational expression holds.

_{tan (θ 0/2) =} (t / 2) / (Φ A / 2) = t / Φ A ··· ( Equation 4)

Magnetic steel plate 21, the center angle per a piece, theta _0. Therefore, the number of magnetic steel plates 21 of the third core element 2C of the inner diameter [Phi _A as N _0, the width direction of the inner diameter side end portion 21a of the magnetic steel plates 21 When placed in close contact with each other without gaps,

N ₀ = 2π / θ ₀ (Formula 5)
It becomes.

As shown in FIG. 6, when the width direction length s of the externally exposed portion 21x is equal to the plate thickness t, the vertex a and the vertex c of the end portion 21b in the width direction outer diameter side of the magnetic steel plate 21 are used. The distance between them is approximately Φ _B π / N ₀ . Here, in the right isosceles triangle abc,

(Φ _B π / N ₀ ) ² = 2t ² (Formula 6)
It becomes.

Here, substituting (Equation 5) into (Equation 6),
{Φ _B π / (π / 2θ ₀ )} ² = 2t ²

By arranging both sides, Φ _B = 2√2t / θ ₀ (Expression 7)
It becomes.

Then, when substituted into (Equation 7) a modified equation θ _0/2 ^{= tan} -1 (Equation 4) (t / [Phi _A), the equivalent expression in the above equation (Equation 2) is obtained.

Next, a condition for s <t is considered when the tilt angle θ _21a is zero (θ _21a = 0).

At this time, in the right triangle abc,
(Φ _B π / N ₀ ) ² = s ² + t ² <2t ² (Equation 8)
It becomes.

Here, if (Equation 5) is substituted into (Equation 8),
Φ _B <2√2t / θ (Equation 9)
It becomes.

Then, substituting the equation (9) deformation equation θ _0/2 ^{= tan} -1 (Equation 4) (t / [Phi _A), inequalities in the relationship (Equation 2) is obtained.

In addition, when the inclination angle θ _21a is 0 <θ _21a <θ _X , a condition for s = t is considered.

Here, first, the angle theta _X will be described. This angle θ _X is an inclination angle θ _21a of the magnetic steel plate 21 when θ ′ is equal to the center angle θ ₀ , which is the angle formed between the radially innermost corner of the adjacent magnetic steel plate 21 and the circle center O. Yes,

, The inclination angle of the magnetic steel sheet 21 when the center angle θ ′ becomes equal to the center angle θ ₀ . This θ _X is smaller than the central angle θ ₀ when the inclination angle θ _21a of the magnetic steel sheet 21 is 0 <θ _21a <θ _X. On the other hand, when the inclination angle θ _21a of the magnetic steel plate 21 is θ _X <θ _21a , the angle θ ′ is larger than the center angle θ ₀ . The derivation of (Equation 1) and θ _X will be described last.

At this time, if the number of laminated magnetic steel plates 21 is N ′, N ′> N ₀ , and the angle between the innermost corner in the radial direction of the adjacent magnetic steel plates 21 and the circle center O is shown in FIG. When the angle is θ ′, θ ′ <θ ₀ .

Then
(Φ _B π / N ′) ² = 2t ² (Equation 10)
N ′ = 2π / θ ′ (Expression 11)
It becomes.

From (Equation 10) and (Equation 11),
{Φ _B π / (π / 2θ ′)} ² = 2t ²

If you organize both sides,
Φ _B = 2√2t / θ ′ (Expression 12)
It becomes.

This (Equation 12) is
Φ _B = 2√2t / θ ′> 2√2t / θ ₀ (∵θ ′ <θ ₀ )
It becomes.

That is, the inclination angle θ _21a of the magnetic steel sheet 21 is θ _21a = 0 so that the outer diameter Φ _B satisfies the condition that the inclination angle θ _21a of the magnetic steel sheet 21 satisfies s = t in the range of 0 <θ _21a <θ _X. It encompasses a range satisfying outer diameters [Phi _B for the of s = t for. Therefore, when the inner diameter Φ _A , the outer diameter Φ _B , and the plate thickness t satisfy the inequality of the above relational expression (Formula 2), the inclination angle θ _21a of the magnetic steel sheet 21 is in the range of 0 <θ _21a <θ _X. In this case, s = t.

Next, a condition for satisfying s <t when the tilt angle θ _21a is 0 <θ _21a <θ _X will be considered.

At this time, in the right triangle abc,
(Φ _B π / N ′) ² = s ² + t ² <2t ² (Equation 13)
It becomes.

Substituting (Equation 11) into (Equation 13),
Φ _B <2√2t / θ ′ (Expression 14)
It becomes.

This (Equation 14) is
Φ _B <2√2t / θ ′> 2√2t / θ ₀ (∵θ ′ <θ ₀ )
It becomes.

That is, the inclination angle θ _21a of the magnetic steel sheet 21 is θ _21a = 0 in the range that the outer diameter Φ _B satisfies so that the inclination angle θ _21a of the magnetic steel sheet 21 satisfies s <t in the range of 0 <θ _21a <θ _X. It encompasses a range satisfying outer diameters [Phi _B for the of s <t for. Therefore, when the inner diameter Φ _A , the outer diameter Φ _B , and the plate thickness t satisfy the inequality of the above relational expression (Formula 2), the inclination angle θ _21a of the magnetic steel sheet 21 is in the range of 0 <θ _21a <θ _X. Even in the case of, s <t.

Next, a condition for satisfying s = t and s <t when the inclination angle θ _21a is θ _21a = θ _X will be considered. At this time, since θ _X = θ ₀ , in each case, the conditions for s = t and s <t in the case of θ _21a = 0 described above are the same.

Next, a condition for s = t is considered when the inclination angle θ _21a is larger than θ _X (θ _21a > θ _X ).

At this time, if the number of magnetic steel plates 21 to be stacked is N ′, N ′ <N ₀ , and the angle between the corner of the radially innermost end of the adjacent magnetic steel plates 21 and the circle center O is shown in FIG. 'If you, θ' the angle θ> θ _0. Further, when the distance between the vertex A and the vertex A ′ is a virtual plate thickness t ′,

tan (θ ′ / 2) = (t ′ / 2) / (Φ _A / 2) = t ′ / Φ _A
Therefore, θ ′ = 2 tan ⁻¹ (t ′ / Φ _A ) (Equation 15)

Also,
(Φ _B π / N ′) ² = 2t ² (Expression 16)
N ′ = 2π / θ ′ (Expression 17)
It becomes.

From (Expression 16) and (Expression 17),
{Φ _B π / (π / 2θ ′)} ² = 2t ²

If you organize both sides,
Φ _B = 2√2t / θ ′ (Expression 18)
It becomes.

Substituting (Equation 18) into (Equation 15),
Φ _B = √2 tan ⁻¹ (t ′ / Φ _A ) (Equation 19)
It becomes.

Here, from the cosine theorem in the triangle OAA ',
(T ′) ² = (Φ _A ) ² + (Φ _A ) ² −2 (Φ _A ) ² cos θ ′,
t ′ = Φ _A √ {(1-cos θ ′) / 2} (Equation 20)
It becomes.

Then, by substituting (Equation 20) into (Equation 19), the equality expression in the above relational expression (Equation 3) is obtained.

Next, a condition for satisfying s <t when the tilt angle θ _21a is larger than θ _X (θ _21a > θ _X ) will be considered.

At this time, in the right triangle abc,
(Φ _B π / N ′) ² = s ² + t ² <2t ² (Formula 21)
It becomes.

Substituting (Equation 17) into (Equation 21),
Φ _B <2√2t / θ ′ (Expression 22)
It becomes.

Then, by substituting (Expression 15) and (Expression 20) into (Expression 22), the inequality in the above relational expression (Expression 3) is obtained.

As described above, the third core element 2C satisfying s ≦ t can be manufactured by selecting the inner diameter Φ _A , the outer diameter Φ _B , and the plate thickness t of the third core element 2C that satisfies the above relational expression. .

As a specific example, when the inclination angle α of the magnetic steel plates 21 is less than theta _X, for example, the inner diameter [Phi _A third core element 2C 550 (mm), the outer diameter Φ _B 600 (mm) and the magnetic steel plates 21 When the plate thickness t is 0.3 (mm), the outer diameter Φ _B (= 600) <777.8≈√2 × 0.3 / (tan ⁻¹ (0.3 / 550)). . Therefore, using the magnetic steel sheet 21 having a thickness t of 0.3 (mm) under the condition that the inclination angle α of the magnetic steel sheet 21 is θ _X or less, the inner diameter Φ _A 550 (mm) and the outer diameter Φ _B 600 (mm ) Of the third core element 2C, the third core element 2C having a width direction length s of the externally exposed portion 21x smaller than the plate thickness t can be obtained.

Further, in the case the inclination angle α of the magnetic steel plates 21 is greater than the theta _X, for example, the inner diameter [Phi _A third core element 2C 550 (mm), 600 the outer diameter Φ _B (mm), a plate of magnetic steel plates 21 When the thickness t is 0.3 (mm) and the virtual plate thickness t ′ obtained from the above (formula 1) is 0.35 (mm), the outer diameter Φ _B (= 600) <666.7≈√2 × 0.3 / (tan ⁻¹ (0.35 / 550)). Therefore, the inclination angle α is larger conditions than theta _X of the magnetic steel plates 21, the plate thickness t by using the magnetic steel plates 21 of 0.3 (mm), an inside diameter Φ _A 550 (mm), outer diameter [Phi _B 600 ( mm) of the third core element 2C, the third core element 2C having a width direction length s of the externally exposed portion 21x smaller than the plate thickness t can be obtained.

Furthermore, in order to show the relationship between the inner diameter Φ _A and the outer diameter Φ _B when s = t, a simulation result is shown in FIG. FIG. 8 shows the relationship of the inner diameter Φ _A when the outer diameter Φ _B is fixed to 60 and the coefficient a is changed in the involute curve (x = a (cos θ + θ sin θ), y = a (sin θ−θ cos θ)). FIG. Note that θ for s = t is 1.25π, 3.25π, and 5.25π.

As can be seen from FIG. 8, when the outer diameter Φ _B is 60, the minimum value of the inner diameter Φ _A is about 42.6 (= 21.3 × 2). That is, the ratio of the inner diameter / outer diameter for s = t is Φ _A / Φ _B > 42.6 / 60 = 0.71.

Furthermore, in order to show the relationship between the inner diameter Φ _A and the outer diameter Φ _B when 2 s = t, a simulation result is shown in FIG. The 9, similar to FIG 8, to fix the outer diameter [Phi _B 60, an involute curve in (x = a (cosθ + θsinθ ), y = a (sinθ-θcosθ)), changing the coefficients a It is a figure which shows the relationship of the internal diameter (PHI) _{A in} a case. Note that θ for satisfying 2s = t is 1.25π, 3.15π, and 5.15π.

As can be seen from FIG. 9, when the outer diameter Φ _B is 60, the minimum value of the inner diameter Φ _A is about 53,7 (= 26.85 × 2). That is, the ratio of the outer diameter / inner diameter for 2s = t is Φ _A / Φ _B > 53.7 / 60 = 0.895. Thus, from the simulation results, it is considered that the ratio of the inner diameter / outer diameter to satisfy s ≦ t needs to satisfy Φ _A / Φ _B > 0.71.

Finally, it is described with reference to FIG. 10 the derivation of the angle theta _X. First, geometric information is described analytically.

A plane L ₁ passing through the point A (R (= Φ _A / 2), 0) of the first magnetic steel plate shown in FIG. 10 is expressed as L ₁ : f (x, y) = 0.
far.

Further, the surface L2 of the _second magnetic steel plate adjacent to the first magnetic steel plate uses the central rotation angle θ ′,
L ₂ : g (f (x, y), θ ′) = 0
It can be expressed as.

Since this surface L ₂ is in contact with the first magnetic steel plate at point B (x _b , y _b ),
g (f (x _b , y _b ), θ ′) = 0
Is established.

Hereinafter, it is assumed that the cross-sectional shapes of the surfaces L ₁ and L ₂ are straight lines. The angle between L ₁ and the x-axis when putting the alpha, geometrically function f is expressed as follows.
L ₁ : f (x, y) = y− (x−R) tan (−α) = 0

Therefore, _{L 2} becomes the following equation.
L ₂ : g (f (x, y), θ ′)
= Y-Rsinθ '-(s-Rsinθ') tan (θ'-α) = 0

If the thickness of the steel sheet is t, the coordinates of the point B are (R + tsin α, t cos α). Substituting the coordinates of the point B to the formula L _2,
tcos α-R sin θ- (R + tsin α-R cos θ) tan (θ-α) = 0
It becomes.

According to this formula, an inner diameter R (= Φ _A / 2) and a sheet thickness t are given, and α obtained by setting θ ′ = θ ₀ is θ _X.

<Effects of First Embodiment>
According to the iron core 1 for stationary induction equipment according to the present embodiment configured as described above, the iron core block 2 is formed by laminating a plurality of cylindrical iron core elements 2A, 2B, and 2C on each other. The volume factor can be improved and iron loss can be reduced. In addition, the gap member 3 can increase or decrease the magnetic resistance in the magnetic path to obtain a desired reactance, and when the magnetic resistance is increased, the amount of leakage magnetic flux penetrating in the radial direction increases. The leakage magnetic flux is equivalently passed along the width direction of the magnetic steel plate 21 provided substantially radially, and eddy current can be reduced. Further, the structure in which the gap member 3 is sandwiched between the iron core blocks 2 formed by shifting and stacking the magnetic steel plates 21 can simplify the manufacturing and reduce the manufacturing cost.

<Other modified embodiments>
The present invention is not limited to the above embodiment. In the following description, the same reference numerals are given to members corresponding to the above-described embodiment.

For example, in the above-described embodiment, the stacking direction of the cylindrical core elements is the same, but the stacking direction may be reversed between the cylindrical core elements.

In the above embodiment, the core block is composed of three cylindrical core elements, but may be composed of two cylindrical core elements or four or more cylindrical core elements. That is, the stationary induction device iron core may be any one that includes two or more cylindrical core elements according to the application.

Furthermore, in the said embodiment, although the magnetic steel plate 21 consisted only of the curved part 211, as shown in FIG. 11, it continues to the inner diameter side edge part in the width direction of the curved part 211 and the said curved part 211 concerned. It may be composed of the bent portion 212 formed in this manner. At this time, the bending angle θ of the bending portion 212 with respect to the bending portion 211 may be, for example, 30 degrees, and the length should be as short as possible, for example, about 3 to 10 times the thickness of the magnetic steel plate 21 is desirable. Thus, if it has a bending part 212, not only can the operation | work which piles up each magnetic steel plate 21 be facilitated, but it can prevent suitably that the magnetic steel plate 21 is pulled out to radial direction exterior. it can.

Second Embodiment
Next, a second embodiment relating to a cylindrical iron core, an induction heating roller device, and a stationary induction device that can suitably suppress eddy currents will be described.

In electromagnetic induction devices such as static induction devices such as transformers and reactors, or induction heat generation devices such as induction heating roller devices, the loss of the iron core that becomes the magnetic path is the cause of reduced efficiency and heat generation of electromagnetic induction devices. Reduction is a major issue.

Especially, the eddy current loss of the iron core due to the leakage magnetic flux occupies a large ratio, and the iron core generates heat due to this eddy current, and the efficiency of the equipment is lowered. Moreover, it becomes a factor which causes the efficiency fall and insulation fall of the induction coil currently wound by this. It is known that the magnitude of the eddy current increases in proportion to the square of the width or thickness of the magnetic steel sheet in which the magnetic flux enters vertically.

Conventionally, as a generally circular iron core generally used, there is a product core as shown in Patent Document 5 (Japanese Patent Laid-Open No. 9-232165). As shown in FIG. 18, this stacked iron core forms a plurality of types of steel plate blocks 200 having different width dimensions by laminating a plurality of magnetic steel plates, and the steel plate blocks 200 are stacked so as to have a substantially circular shape. It is formed by.

However, there is a problem that the end surfaces 200a of the steel plate blocks 200 located at both ends in the stacking direction (upper and lower ends in FIG. 18) become large, and a large eddy current is generated on the end surfaces 200a. Further, there is a problem that eddy currents are also generated in the externally exposed portion 200b of the laminated surface of each steel plate block 200.

Here, in order to reduce eddy current, the number of magnetic steel plates stacked in each steel plate block 200 is simply reduced, the number of types of steel plate blocks 200 having different width dimensions is increased, and the steel plate blocks 200 are positioned at both upper and lower ends. It is conceivable to reduce the externally exposed portion 200b formed on the end surface 200a of the steel plate block 200 and the outer surface of the iron core.

However, if the types of the steel plate blocks 200 are increased, there are problems such as an increase in manufacturing cost and a complicated operation.

Also, recently, it has been considered that a large number of magnetic steel plates having a long flat plate shape cut in a narrow width are arranged in a radial shape by arranging them radially. According to this, generation | occurrence | production of the eddy current by a leakage magnetic flux penetrating a magnetic steel plate can be made small, and it becomes possible to reduce the emitted-heat amount of an iron core.

However, it is extremely troublesome to arrange thin magnetic steel plates radially along a certain circumference. Even if the inner ends of the magnetic steel plates are arranged closely, a gap is formed between the outer ends of the adjacent magnetic steel plates. For this reason, it is necessary to work such as filling the gap by sandwiching another narrow magnetic steel plate in the gap.

Further, in order to eliminate the gap at the outer end of the magnetic steel plate, the inner ends of the magnetic steel plates arranged in a radial manner are fixed to the outer periphery of the pipe by welding, and the magnetic steel plate is pressurized from the outer end of the magnetic steel plate while rotating the pipe. Although it is conceivable to bend the steel plate, welding work, pipe rotation work, pressurization work, etc. are required. These operations are extremely difficult when manufacturing a large iron core (for example, an axial length of 7 m).

In addition, as shown in Patent Document 4 (Japanese Patent Laid-Open No. 2000-311777) and Patent Document 6 (Registered Utility Model No. 2532986), a plurality of magnetic steel plates having a curved portion having a curved cross section in the width direction are provided. The present applicant has considered a cylindrical iron core formed by stacking in the width direction.

However, in any cylindrical iron core, the idea of stacking magnetic steel plates in a cylindrical shape is limited, and it is focused on how to stack magnetic steel plates specifically, that is, the thickness of magnetic steel plates and the lamination of magnetic steel plates There is nothing that pays attention to the relationship with the width direction length of the externally exposed portion on the side surface.

Therefore, the present invention was made for the first time by paying attention to the relationship between the thickness of the magnetic steel sheet and the width in the width direction of the externally exposed portion on the side surface of the magnetic steel sheet, and was made to solve the above problems all at once. Therefore, it is a main intended problem to suppress as much as possible the eddy current caused by the leakage magnetic flux generated in the magnetic steel sheet while reducing the manufacturing cost with a simple configuration.

That is, the cylindrical iron core according to the present invention is a cylindrical iron core formed by stacking a plurality of magnetic steel plates having a curved portion whose cross section in the width direction forms a curved shape, shifted in the width direction. The widthwise length of the externally exposed portion on the side surface of the lamination side is equal to or less than the thickness of the magnetic steel plate.

In such a case, in the cylindrical iron core, when the length of the externally exposed portion in the width direction is s and the thickness of the magnetic steel sheet is t, s ≦ t is established, and the eddy current is Since the width of the generated portion is the same as the thickness of the magnetic steel plate, the maximum eddy current value can be made as small as possible. Therefore, by deviating and stacking the magnetic steel plates, it is possible to prevent a reduction in the magnetic properties of the cylindrical iron core such as iron loss caused by the generation of eddy currents while realizing a simple configuration and a reduction in manufacturing cost. It is possible to prevent a decrease in efficiency of the device and a heat generation such as a decrease in electrical characteristics and insulation characteristics of the induction coil.

As a concrete embodiment for setting the width direction length s of the externally exposed portion to be equal to or less than the thickness t of the magnetic steel sheet, the inner diameter Φ _A , the outer diameter Φ _{B of} the cylindrical iron core, and the magnetic steel sheet The thickness t is

(Here, α is an inclination angle with respect to the radial direction of the inner circle of the cylindrical iron core, and θ ′ is a central angle formed between the angle of the radially innermost end of the adjacent magnetic steel sheet and the circle center. The unit of the trigonometric function is radians), and the inclination angle α of the magnetic steel sheet when the central angle θ ′ is equal to the central angle θ ₀ when the inclination angle of the magnetic steel sheet is zero. When θ _X is set and the inclination angle α of the magnetic steel sheet is equal to or less than θ _X ,

If the inclination angle α of the magnetic steel plates is greater than theta _X, using the central angle theta 'satisfying the above equation (1)

It is to make a relationship.

The ratio (Φ _A / Φ _B ) of the inner diameter Φ _A of the cylindrical iron core to the outer diameter Φ _B of the cylindrical iron core for setting the widthwise length s of the external exposed portion to be equal to or less than the plate thickness t of the magnetic steel sheet is 0.71 or more.

Further, it is desirable to use the cylindrical iron core of the present invention for the induction heating roller device, and in particular, the induction heating roller device includes a magnetic flux generation mechanism configured by winding an induction coil around the outer peripheral surface of the cylindrical iron core; A hollow cylindrical heating roll body that houses the magnetic flux generation mechanism and is provided so as to be rotatable relative to the magnetic flux generation mechanism, and generates heat by an induced current generated by the magnetic flux of the magnetic flux generation mechanism, It is desirable that a non-magnetic material or a gap at a predetermined interval is interposed between the cylindrical iron core and the heat generating roll body. Here, the non-magnetic material is a substance that does not exhibit magnetism, such as aluminum, and includes ceramics or glass. Moreover, the space | gap of a predetermined space | interval is a space | gap which has a space | interval of the grade which makes only the effective surface length part of a heat-generating roll body generate | occur | produce only heat, and does not generate | occur | produce another part easily, and may be vacuum or air | atmosphere.

Thus, the effective surface length of the heat generating roll body is increased by interposing a non-magnetic body or a gap at a predetermined interval between the cylindrical iron core and the heat generating roll body, thereby increasing the magnetic resistance and making the magnetic flux difficult to pass. Only the portion generates heat, and other portions (for example, a journal portion connected to the heat-generating roll body) are made difficult to generate heat.

At this time, by providing a non-magnetic material or a gap at a predetermined interval between the cylindrical iron core and the heating roller body, the magnetic flux amount of the leakage magnetic flux that is released from the outer peripheral surface of the cylindrical iron core in the radial direction to the outside Will increase. However, by using the cylindrical iron core of the present invention, eddy current loss due to leakage magnetic flux, that is, iron loss is suppressed, and self-heating of the magnetic flux generation mechanism itself is prevented.

Furthermore, it is desirable to use the cylindrical iron core of the present invention for a stationary induction device. In particular, it is desirable that a leg iron core configured using a cylindrical iron core is provided, and a nonmagnetic material is provided on at least one of both axial ends of the cylindrical iron core. For example, when used as a reactor among static induction devices, the magnetic resistance in the magnetic path can be increased, and a predetermined reactance can be obtained. In addition, increasing the magnetic resistance increases the amount of magnetic flux leaked from the outer peripheral surface of the leg core in the radial direction and released to the outside. However, by using the cylindrical core of the present invention, the vortex Generation of current can be suppressed as much as possible.

As described above, according to the present invention, the maximum eddy current value due to the leakage magnetic flux generated in the magnetic steel sheet is suppressed as much as possible while reducing the manufacturing cost with a simple structure, and the magnetic core generated by the generation of the eddy current is suppressed. The deterioration of the characteristics, the electrical characteristics of the induction coil, and the insulation characteristics can be solved.

Next, the induction heating roller device using the cylindrical iron core of the second embodiment will be described with reference to the drawings. In addition, it demonstrates using the code | symbol different from the said 1st Embodiment.

<Device configuration>
The induction heating roller device 1 according to the present embodiment is used in, for example, a continuous heat treatment process of a sheet material or web material such as a resin film, paper, cloth, nonwoven fabric, or metal foil, or a heat drawing process of synthetic fibers. And a hollow cylindrical heating roller body 2 that is rotatably provided, and a magnetic flux generation mechanism 3 accommodated in the heating roller body 2.

The journal 4 is attached to both ends of the heating roller body 2. The journal 4 is configured integrally with a hollow drive shaft 5, and the drive shaft 5 is rotatably supported on a base 7 via a bearing 6 such as a rolling bearing.

The magnetic flux generation mechanism 3 includes a cylindrical iron core 31 having a cylindrical shape and an induction coil 32 wound around the outer peripheral surface of the cylindrical iron core 31. Support rods 8 are attached to both ends of the cylindrical iron core 31, respectively. Each of the support rods 8 is inserted into the drive shaft 5 and is rotatably supported with respect to the drive shaft 5 via a bearing 9 such as a rolling bearing. Thereby, the magnetic flux generation mechanism 3 is supported in a suspended state inside the heat generating roller body 2. A lead wire 10 is connected to the induction coil 32, and an AC power source (not shown) for applying an AC voltage is connected to the lead wire 10.

Further, a gap or a non-magnetic material (not shown) with a predetermined interval is provided between the cylindrical iron core 31 and the heat generating roll body 2 or the journal 4. Specifically, as shown in FIG. 12, a gap G of a predetermined interval is provided between both ends of the cylindrical iron core 31 and the iron core side surface 4 a of the journal 4. By providing the gap G in this manner, the magnetic resistance is increased to make it difficult for the magnetic flux to pass through, so that only the heat generating roll body 2 generates heat and the journal 4 and the like hardly generate heat.

Thus, as shown in FIG. 13, the cylindrical iron core 31 of the present embodiment is formed in a cylindrical shape by stacking a plurality of magnetic steel plates 311 shifted in the width direction.
The magnetic steel plate 311 has a long shape, and has a curved portion 3111 having a curved cross section in the width direction as shown in FIG. The magnetic steel plate 311 is formed of, for example, a silicon steel plate having an insulating film on its surface, and the thickness thereof is, for example, about 0.3 mm.

The curved portion 3111 may be curved with a constant curvature throughout, or may be curved while the curvature continuously changes. For example, an involute shape using a part of an involute curve, a partial arc A shape or a partial ellipse shape is conceivable.

Then, each magnetic steel plate 311 is shifted in the width direction so that the convex portion formed by the curved portion 3111 of another magnetic steel plate 311 is fitted into the concave portion formed by the curved portion 3111 of the magnetic steel plate 311. Then, a large number of magnetic steel plates 311 having the same shape are overlapped. At this time, the end portions 311a and 311b in the width direction of the magnetic steel plate 311 are in contact with the concave side surface 311m or the convex side surface 311n of the adjacent magnetic steel plate 311. In this way, the cylindrical iron core 31 having a cylindrical shape is formed.

Further, as shown in the partial enlarged view of FIG. 13, the cylindrical iron core 31 has a width-direction length s of the externally exposed portion 311 x on the side of the laminated side of the magnetic steel plate 311 that is equal to or less than the plate thickness t of the magnetic steel plate 311. Magnetic steel plates 311 are stacked. That is, if the thickness t of the magnetic steel plate 311 is 0.3 mm, the length s in the width direction of the externally exposed portion 311x is set to 0.3 mm or less.

The laminated side surface of the magnetic steel plate 311 is the convex side surface 311n of the curved portion 3111 among the side surfaces 311m and 311n facing the adjacent magnetic steel plate 311. And in this lamination | stacking side surface, the surface formed outside the width direction outer-diameter side edge part 311b of the magnetic steel plate 311 to contact is the external exposure part 311x.

Furthermore, as shown in FIG. 14, the width direction inner diameter side end 311a of the magnetic steel plate 311 has an inclination angle of the center line of the width direction inner diameter side end 311a with respect to the radial direction of the inner circle of the cylindrical iron core. It is provided so as to have θ _311a . That is, the width direction inner diameter side end portion 311a of the magnetic steel plate 311 is provided so as to contact a position equal to or less than the plate thickness dimension in the outer diameter direction from the width direction inner diameter side end portion 311a of the adjacent magnetic steel plate 311. .

The cylindrical iron core 31 of the present embodiment has an inner diameter Φ _A , an outer diameter Φ _B of the cylindrical iron core 31, and a thickness t of the magnetic steel plate 311.

(Here, α is an inclination angle θ311 with respect to the radial direction of the inner circle of the cylindrical iron core 31, and θ ′ is a central angle formed between the angle of the innermost end in the radial direction of the adjacent magnetic steel plate 311 and the center of the circle. (Note that the unit of trigonometric function is radian.)

The central angle theta 'is the inclination angle of the magnetic steel plates 311 when the inclination angle theta ₃₁₁ of the magnetic steel plates 311 becomes equal to the central angle theta ₀ in the case of zero α of (= theta ₃₁₁₎ and theta _X,

When the inclination angle α of the magnetic steel plate 311 is θ _X or less,

If the inclination angle α of the magnetic steel plates 311 is greater than theta _X, using the central angle theta 'satisfying the above equation (1)

It is configured so that

As shown in FIG. 15, the relational expression (formula A) and the relational expression (formula B) are such that the width direction length s of the externally exposed portion 311x and the plate thickness t of the magnetic steel plate 311 satisfy s ≦ t. It shows the inner diameter [Phi _a and outer diameter [Phi _B relationship of the cylindrical core 31. Here, the inner diameter [Phi _A cylindrical iron core 31, the diameter of a circle inscribed in the width direction of the inner diameter side end portion 311a of the magnetic steel plate 311, and the outer diameter [Phi _B of the cylindrical iron core 31, the magnetic steel plate This is the diameter of a circle circumscribing the width direction outer diameter side end 311b of 3311 (see FIG. 13). The description of the above formula is the same as in the first embodiment, and will be omitted.

<Effects of Second Embodiment>
According to the induction heating roller device 1 according to this embodiment configured as described above, in the cylindrical iron core 31, the width dimension of the portion where the eddy current is maximum is equal to or less than the plate thickness t of the magnetic steel plate 311, and the maximum eddy current value is obtained. Can be made as small as possible. Therefore, the iron loss of the cylindrical iron core 31 can be reduced while realizing a simple configuration and a reduction in manufacturing cost by staggering and stacking the magnetic steel plates 311. As a result, the efficiency of the device can be reduced and heat generation can be prevented. Can do.

Further, by providing a gap between the cylindrical iron core 31 and the heat generating roll body 2, the magnetic resistance is increased to make it difficult for the magnetic flux to pass through, and only the effective surface length portion of the heat generating roll body 2 generates heat. In this case, the eddy current loss, that is, iron loss is suppressed against the increased leakage magnetic flux, and the self-heating of the magnetic flux generating mechanism 3 itself is not caused. Can be prevented. Furthermore, although the magnetic flux generating mechanism 3 is heated by heat transfer due to radiation and convection from the heat roller body 2, heat transfer to a portion other than the heat roller body 2 can be reduced by a non-magnetic material or a gap at a predetermined interval. it can.

In addition, for example, the cylindrical iron core 31 can be used for a stationary induction device. The case where it uses for the reactor Z among static induction apparatuses with FIG. 16 is demonstrated. The reactor Z includes one or more (two in FIG. 16) leg iron cores Z1, a coil Z2 wound around the outer circumference of the leg iron core Z1, and the plurality of leg iron cores Z1 at each end. And a yoke iron core Z3 that forms a closed magnetic path. In the figure, Z5 is a fastening bolt for fastening the leg iron core Z1. And each leg iron core Z1 is formed with one or a plurality of gaps. Specifically, the leg iron core Z <b> 1 is formed of a plurality of cylindrical iron cores 31. In each leg iron core Z1, a spacer member Z4 made of an insulator is sandwiched between the respective cylindrical iron cores 31, thereby forming one or more gaps in the leg iron core Z1. A spacer member Z4 is also disposed between the yoke iron core Z3 and the cylindrical iron core 31.

Thus, a predetermined reactance can be obtained by adjusting the magnetic resistance by the gap. Further, when the magnetic resistance is increased, the leakage magnetic flux increases. However, since the length in the width direction of the externally exposed portion 311x of the magnetic steel plate 311 is equal to or less than the thickness t of the magnetic steel plate 311, the eddy current is increased. It can be suppressed as much as possible.

It is also conceivable to use the cylindrical iron core of the above embodiment for a stationary induction device connected to an electric circuit using a semiconductor element having a gate circuit. A semiconductor element having a gate circuit has an effect as an energization switch, but the flowing current is a current including a large amount of harmonic components whose sine wave shape is broken. Therefore, the magnetic flux flowing in the magnetic circuit of the static dielectric device also contains a large amount of harmonic components, and an eddy current loss proportional to the square of the frequency occurs in the cylindrical iron core. Also, eddy current loss due to leakage magnetic flux occurs. At this time, eddy current loss can be suppressed as much as possible by using the cylindrical iron core.

Furthermore, the cylindrical iron core of the above embodiment has a single layer in the radial direction, but may be of a multilayer structure in the radial direction, particularly when used for a reactor or a transformer.

In addition, in the above-described embodiment, a gap having a predetermined interval is provided between the cylindrical iron core and the heat generating roll body or the journal, but a non-magnetic body may be provided instead of the gap. In this case, it can be considered to apply to the cantilever induction heating roller device shown in FIG. That is, a flange 31 f is provided at one end of the cylindrical iron core 31, and the flange 31 f is fixed to the base 11 by, for example, screwing. The heat generating roll body 2 is rotatably supported by the drive shaft 12 inserted into the cylindrical iron core 31.

In addition, some or all of the above-described embodiments and modified embodiments may be combined as appropriate, and the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. .

According to the present invention, the deterioration of the magnetic properties of the iron core such as iron loss can be suppressed as much as possible by improving the space factor and reducing the eddy current.

Claims (7)

1. An iron core for stationary induction equipment formed by concentrically laminating a plurality of cylindrical core elements formed by stacking a plurality of magnetic steel plates having curved portions whose cross sections in the width direction are curved. .
2. A plurality of core blocks formed by concentrically laminating a plurality of cylindrical core elements formed by stacking a plurality of magnetic steel plates having a curved portion whose cross section in the width direction forms a curved shape, shifted in the width direction; and ,
   The iron core for stationary induction equipment according to claim 1, further comprising a magnetic gap provided between the iron core blocks.
3. 3. The iron core for stationary induction equipment according to claim 2, wherein the magnetic gap is formed by sandwiching a gap member made of a non-magnetic material between the iron core blocks.
4. 2. The length in the width direction of the externally exposed portion on the side surface of the laminated side of the magnetic steel plates constituting the cylindrical core element provided on the radially outermost side of the iron core block is equal to or less than the plate thickness of the magnetic steel plates. Iron core for stationary induction equipment.
5. An inner diameter Φ _A , an outer diameter Φ _{B of} the cylindrical core element provided on the outermost radial direction of the iron core block, and a plate thickness t of the magnetic steel sheet,
   

   

   (Where α is the inclination angle of the magnetic steel sheet with respect to the radial direction of the inner circle of the cylindrical iron core element, and θ ′ is the central angle formed between the angle of the radially innermost end of the adjacent magnetic steel sheet and the circle center. Note that the unit of the trigonometric function is radians).
   The tilt angle α of the magnetic steel sheet when the center angle θ ′ is equal to the center angle θ ₀ when the tilt angle of the magnetic steel sheet is zero is θ _X ,
   When the inclination angle α of the magnetic steel sheet is θ _X or less,
   

   

   When the inclination angle α of the magnetic steel sheet is larger than θ _X , the central angle θ ′ satisfying the above (Equation 1) is used.
   

   

   The iron core for stationary induction equipment according to claim 4, wherein:
6. A cylindrical iron core formed by stacking a plurality of magnetic steel plates having a curved portion having a curved cross section in the width direction, shifted in the width direction,
   A cylindrical iron core in which a length in a width direction of an externally exposed portion on a laminated side surface of the magnetic steel sheet is equal to or less than a thickness of the magnetic steel sheet.
7. The cylindrical iron core has an inner diameter Φ _A , an outer diameter Φ _B , and a thickness t of the magnetic steel sheet.
   

   

   (Here, α is an inclination angle with respect to the radial direction of the inner circle of the cylindrical iron core, and θ ′ is a central angle formed between the angle of the radially innermost end of the adjacent magnetic steel sheet and the circle center. , The unit of the trigonometric function is radians).
   The tilt angle α of the magnetic steel sheet when the center angle θ ′ is equal to the center angle θ ₀ when the tilt angle of the magnetic steel sheet is zero is θ _X ,
   When the inclination angle α of the magnetic steel sheet is θ _X or less,
   

   

   If the inclination angle α of the magnetic steel plates is greater than theta _X, using the central angle theta 'satisfying the above equation (1)
   

   

   The cylindrical iron core according to claim 6 having the relationship of

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