JP5213571B2 - Cylindrical iron core, induction heating roller device and stationary induction device - Google Patents

Description

  The present invention relates to a cylindrical iron core, an induction heating roller device, and a stationary induction device that can suitably suppress eddy currents.

  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.

  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.

  Conventionally, as a substantially circular iron core generally used, there is a stacked iron core as shown in Patent Document 1. As shown in FIG. 14, the laminated 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. 14) 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 steel plate blocks 200 are increased, there are problems such as an increase in manufacturing cost and complicated operations.

  In addition, recently, it has been considered that a plurality of magnetic steel plates having a long flat plate shape cut into 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, the work of arranging narrow magnetic 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. 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 2 and Patent Document 3, etc., a cylindrical iron core formed by stacking a plurality of magnetic steel plates each having a curved portion having a curved cross section in the width direction shifted in the width direction is the main core. Is considered by the applicant.

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.
JP-A-9-232165 Registered Utility Model No. 2532986 JP 2000-311777 A

  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 plate 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).

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)

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, an embodiment of the induction heat roller device 1 using the cylindrical iron core 31 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the configuration of the induction heat roller device 1 of the present 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.

  Journals 4 are 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 nonmagnetic material (not shown) having 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. 1, a gap G with 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.

  Therefore, as shown in FIG. 2, 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. 2, the cylindrical iron core 31 has a width-direction length s of the externally exposed portion 311 x on the side surface on the laminated side of the magnetic steel plate 311 so as to be equal to or less than the 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.

Further, as shown in FIG. 3, the width direction inner diameter side end 311a of the magnetic steel plate 311 has an inclination angle 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 comprised so that it may become a relationship.

As shown in FIG. 4, the relational expression (formula 2) and the relational expression (formula 3) 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. 2).

For simplicity, the width direction inner diameter side end 311a of the magnetic steel plate 311 is perpendicular to the inner diameter of the cylindrical core 31 (the inclination angle θ _311a of the center line of the width direction inner diameter side end _311a is zero (θ _311a = FIG. 5 shows an explanatory diagram thereof. At this time, the center line of the straight line and the magnetic steel plate 311 connecting the corners and circle center O of the widthwise inner diameter side end portion 311a of the magnetic steel plates 311 (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 311, the center angle per a piece, theta _0. Therefore, the number of magnetic steel plates 311 of the cylindrical core 31 of the inner diameter [Phi _A as _{N 0,} the contact width direction inner diameter side end portion 311a of the magnetic steel plates 311 to each other If it is arranged densely 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 311x is equal to the plate thickness t, the width between the apex a and the apex c of the end portion 311b in the width direction outer diameter side of the magnetic steel plate 311 The distance 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

If you organize 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 _satisfying s <t when the tilt angle θ _311a is zero (θ _311a = 0) will be considered.

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 ₀ (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 _311a is 0 <θ _311a <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 _311a of the magnetic steel sheet 311 when the angle θ ′ formed between the radial innermost end angle of the adjacent magnetic steel sheet 311 and the circle center O becomes equal to the center angle θ _0. Yes,

, The inclination angle of the magnetic steel sheet 311 when the center angle θ ′ is equal to the center angle θ ₀ . This θ _X is smaller than the central angle θ ₀ when the inclination angle θ _311a of the magnetic steel plate 311 is 0 <θ _311a <θ _X. On the other hand, when the inclination angle θ _311a of the magnetic steel plate 311 is θ _X <θ _311a , 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 magnetic steel plates 311 to be stacked is N ′, N ′> N ₀ , and the angle between the innermost corner in the radial direction of the adjacent magnetic steel plates 311 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.

In other words, the outer diameter Φ range satisfying the _B to the inclination angle theta _311a becomes s = t in a range of 0 <θ _311a <θ _X of the magnetic steel plates 311, the inclination angle theta _311a is theta _311a = 0 of the magnetic steel plates 311 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 _311a of the magnetic steel plate 311 is in the range of 0 <θ _311a <θ _X. In this case, s = t.

Next, a condition for _satisfying s <t when the inclination angle θ _311a is 0 <θ _311a <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.

In other words, the outer diameter Φ range satisfying the _B to the inclination angle theta _311a becomes s <t in the range of 0 <θ _311a <θ _X of the magnetic steel plates 311, the inclination angle theta _311a is theta _311a = 0 of the magnetic steel plates 311 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 _311a of the magnetic steel plate 311 is in the range of 0 <θ _311a <θ _X. Even in the case of, s <t.

Next, a condition for _satisfying s = t and s <t when the inclination angle θ _311a is θ _311a = 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 _311a = 0 described above are the same.

Next, a condition for s = t when the inclination angle θ _311a is larger than θ _X (θ _311a > θ _X ) will be considered.

At this time, if the number of magnetic steel plates 311 to be stacked is N ′, N ′ <N ₀ , and as 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 inclination angle θ _311a is larger than θ _X (θ _311a > 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 cylindrical core 31 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 cylindrical core 31 satisfying the above relational expression.

As a specific example, when the inclination angle α of the magnetic steel plates 311 is less than theta _X, for example, the inner diameter [Phi _A cylindrical iron core 31 550 (mm), thickness of the outer diameter Φ _B 600 (mm) and the magnetic steel plates 311 When t is 0.3 (mm), the outer diameter Φ _B (= 600) <777.8≈√2 × 0.3 / (tan ⁻¹ (0.3 / 550)). Therefore, the inclination angle α is theta _X the following conditions of the magnetic steel plates 311, the thickness t by using the magnetic steel plates 311 of 0.3 (mm), an inside diameter Φ _A 550 (mm), the outer diameter Φ _B 600 (mm In the case where the cylindrical iron core 1 is manufactured, the cylindrical iron core 1 in which the width direction length s of the externally exposed portion 311x is smaller than the plate thickness t can be obtained.

Further, in the case the inclination angle α of the magnetic steel plates 311 is greater than theta _X, for example, the inner diameter [Phi _A cylindrical iron core 31 550 (mm), 600 the outer diameter Φ _B (mm), the thickness t of the magnetic steel plates 311 Is 0.3 (mm) and the virtual thickness t ′ obtained from the above (Equation 1) is 0.35 (mm), the outer diameter Φ _B (= 600) <666.7≈√2 × 0 .3 / (tan ⁻¹ (0.35 / 550)). Therefore, under the condition that the inclination angle α of the magnetic steel plate 311 is larger than θ _X , the inner diameter Φ _A 550 (mm) and the outer diameter Φ _B 600 ( mm) cylindrical iron core 1 is manufactured, a cylindrical iron core 1 in which the length s in the width direction of the externally exposed portion 311x is 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 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.

  <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, the cylindrical iron core 31 of the present invention can be used for a stationary induction device. The case where it uses for the reactor Z among static induction apparatuses with FIG. 11 is demonstrated. The reactor Z includes one or a plurality of (two in FIG. 11) leg iron cores Z1, coils Z2 wound around the outer circumference of the leg iron cores 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.

  Thereby, 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-described 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, in the said embodiment, although the magnetic steel plate consisted only of the curved part 211, as shown in FIG. 12, 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, 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. However, a nonmagnetic material 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. .

The typical block diagram of the induction heating roller apparatus using the cylindrical iron core of this invention. Sectional drawing of the cylindrical iron core 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) _311a = 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 expansion schematic diagram which shows the width direction inner diameter side edge part of a magnetic steel plate. 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. The typical block diagram of the reactor using the cylindrical iron core of this invention. Sectional drawing which shows the modification of a magnetic steel plate. The typical block diagram of the cantilever type induction heating roller apparatus which concerns on deformation | transformation embodiment. Sectional drawing which shows the structure of the conventional stacked iron core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Induction heat roller apparatus 2 ... Heat-generating roll body 3 ... Magnetic flux generation mechanism 31 ... Cylindrical iron core 311 ... Magnetic steel plate 3111 ... Curved part 311n ... Convex side surface (lamination) Side)
311x: Externally exposed portion s: Length in width direction t: Plate thickness Φ _{A of} magnetic steel plate _A : Inner diameter Φ of cylindrical iron core _B : Outer diameter 32 of cylindrical iron core Induction Coil Z ・ ・ ・ Static induction device (reactor)
Z1 ... leg iron core

Claims (5)

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. 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 1, wherein: 3. The cylindrical core according to claim 1, wherein a ratio (Φ _A / Φ _B ) of an inner diameter Φ _A of the cylindrical core to an outer diameter Φ _B of the cylindrical core is 0.71 or more. A magnetic flux generation mechanism configured by winding an induction coil on the outer peripheral surface of the cylindrical iron core according to claim 1, 2 or 3,
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,
An induction heating roller device in which a non-magnetic material or a gap having a predetermined interval is interposed between the cylindrical iron core and the heating roll body. A leg iron core constituted by using the cylindrical iron core according to claim 1, 2, or 3,
A stationary induction device in which a nonmagnetic material is provided on at least one of both axial ends of the cylindrical iron core.