JP5213574B2 - Iron core for static induction equipment - Google Patents

Description

  The present invention relates to a circular iron core used for static induction equipment such as a transformer or a reactor.

  In static induction devices such as transformers and reactors, the loss of the iron core, which is a magnetic path, causes a reduction in the efficiency of the device and heat generation, 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 the purpose of 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 is provided between the iron cores in order to obtain an appropriate 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

  Therefore, the present invention has been made to solve the above problems all at once, while improving the space factor and reducing the eddy current while simplifying the production and reducing the production cost. The main goal is to suppress the deterioration of the magnetic properties of the iron core as much as possible.

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. A magnetic steel sheet comprising a plurality of core blocks formed by laminating and a magnetic gap provided between the core blocks, and constituting a cylindrical core element provided on the radially outermost side of the core blocks The side surface on the laminated side of the magnetic steel sheet constituting the cylindrical core element provided on the outermost radial direction of the core block is inclined with respect to the radial direction of the cylindrical core element. The length of the externally exposed portion in the width direction is less than the thickness of the magnetic steel plate .

Thus, according to the present invention, the iron core block is formed by laminating a plurality of cylindrical iron core elements on each other, the space factor can be improved, and the iron loss can be reduced. . In addition, 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 amount of leakage magnetic flux penetrating in the radial direction increases. Magnetic flux passes equivalently along the width direction of the magnetic steel plate provided substantially radially, and eddy current can be reduced. Here, since the length in the width direction of the externally exposed portion on the side surface on the lamination side of the magnetic steel plate 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 plate, the maximum The eddy current value can be made as small as possible. 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

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.

  Is to make a relationship.

  As described above, according to the present invention, the reduction of the magnetic properties of the iron core such as iron loss is suppressed as much as possible by improving the space factor and reducing the eddy current while simplifying the manufacturing and reducing the manufacturing cost. can do.

  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 the radial direction concentrically. 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.

  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 includes 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 iron core blocks 2 so that the iron 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. Are sequentially stacked to form the second iron core element 2B. While maintaining this shape, the first core element 2A, the cylindrical member, and the like are extracted from the second core element 2B, the second core element 2B is subjected to strain relief annealing, and then the first core element 2A is again used as the second core element 2A. 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.

  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 unit of the trigonometric function is rad.)

The tilt angle α (= θ _21a ) of the magnetic steel plate 21 when the center angle θ ′ is equal to the center angle θ ₀ when the tilt angle θ _21a of the magnetic steel plate 21 is zero is θ _X ,

When the inclination angle α of the magnetic steel plate 21 is θ _X or less,

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 comprised so that it may become a relationship.

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 (Formula 10) and (Formula 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 ^') a ^{_{2 = (Φ A) 2 +}} (Φ A) 2 -2 (Φ A) 2 cosθ',
t ′ = Φ _A √ {(1-cos θ ′) / 2} (Equation 20)
It becomes.

  Then, by substituting (Expression 20) into (Expression 19), the equality expression in the above relational expression (Expression 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 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 between 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-Rsin θ '-(s-Rsin θ') 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.

<Effect of this 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 embodiment, the stacking direction of the cylindrical core elements is the same, but the stacking direction may be reversed between the cylindrical core elements.

  Moreover, in the said embodiment, although the iron core block was comprised by three cylindrical core elements, you may be comprised from 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 consisted only of the curved part 211, as shown in FIG. 11, it follows the curved part 211 and the inner diameter side edge part in the width direction of the said curved part 211. It may consist of the formed bent portion 212. 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.

  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. .

The perspective view of the iron core for static induction equipment concerning one embodiment of the present invention. The top view of the iron core for static induction apparatuses of the embodiment. Sectional drawing which shows the magnetic steel plate of the embodiment. The figure which shows the relationship between the plate | board thickness of an externally exposed part and a magnetic steel plate. The enlarged schematic diagram which shows the width direction inner diameter side edge part of a magnetic steel plate ((theta) _21a = 0). The figure which shows the distance of the outer side 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. The enlarged schematic diagram which shows the width direction inner diameter side edge part of a magnetic steel plate (0 <(theta) _21a ). The figure which shows a simulation result. The figure which shows a simulation result. The figure for demonstrating derivation | leading-out of angle (theta) _X. Sectional drawing which shows the modification of a magnetic steel plate.

DESCRIPTION OF SYMBOLS 1 ... Iron core 2 for stationary induction | guidance | derivation apparatus ... Iron core block 2A, 2B, 2C ... Cylindrical iron core element 21 ... Magnetic steel plate 211 ... Curved part 3 ... Gap

Claims (3)

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 has a curved shape, shifted in the width direction; and ,
A magnetic gap provided between the iron core blocks ,
The width direction inner diameter side end of the magnetic steel sheet constituting the cylindrical core element provided on the outermost radial direction of the core block is inclined with respect to the radial direction of the cylindrical core element,
The iron core for stationary induction equipment in which the length in the width direction of the externally exposed portion on the side surface on the laminated side of the magnetic steel sheet constituting the cylindrical core element provided on the radially outermost side of the core block is less than the thickness of the magnetic steel sheet .   2. The iron core for stationary induction equipment according to claim 1, wherein the magnetic gap is formed by sandwiching a gap member made of a non-magnetic material between the iron core blocks. 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 static induction equipment according to claim 1 or 2, wherein