JP2003318046A - Dc reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a DC reactor that can suppress the local demagnetization of a permanent magnet caused by the leakage flux from a coil. <P>SOLUTION: The main yoke of the DC reactor is constituted by vertically combining an E-shaped laminated core 10 with an I-shaped laminated core 11 and the coil 12 is wound around the center leg 10C of the core 10. On the other hand, protruded auxiliary yokes 13 and 14 are formed in the main yoke on both sides of the main magnetic gap G of the main yoke in the vertical direction and, in addition, the permanent magnet 15 is provided between the auxiliary yokes 13 and 14 so that a magnetic gap Gs may be secured between the magnet 15 and the main yoke. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC reactor.

[0002]

2. Description of the Related Art Conventionally, as a DC reactor provided in an industrial electromagnetic device such as an inverter circuit, there is a DC reactor configured to apply a bias magnetic field by using a permanent magnet. As this type of DC reactor, for example, Japanese Patent Publication No.
There is one disclosed in Japanese Patent Laid-Open No. 6-37128 (hereinafter referred to as Prior Art 1).

In the DC reactor of the prior art 1, while the I-shaped forming layer core and the E-shaped forming layer core are vertically combined, a gap (hereinafter referred to as a magnetic gap) is provided between them, and the entire magnetic gap is permanent. A bias magnetic field is applied by inserting a magnet. In the DC reactor of Prior Art 1, since the coil magnetic flux generated by the coil wound around a part of the E-shaped layer core 10 entirely penetrates the inside of the permanent magnet, the coil magnetic flux reduces the permanent magnet. There is a problem that it is easy to magnetize.

Therefore, conventionally, there has been proposed a method for suppressing the demagnetization of the permanent magnet by preventing the coil magnetic flux generated by the coil from entirely penetrating the inside of the permanent magnet.

FIG. 9 shows an example of such a method.
The DC reactor of Japanese Patent Publication No. 49 (hereinafter referred to as Prior Art 2) is shown. In the DC reactor of Prior Art 2, a C-shaped iron core 1 and a T-shaped iron core 2 are vertically combined to form a yoke, and a magnetic gap 3 is provided between the C-shaped iron core 1 and the T-shaped iron core 2. There is. Further, permanent magnets 4 extend vertically across the magnetic gap 3 and are arranged in close contact with the side surfaces of the C-shaped layer core 1 and the T-shaped layer core 2, respectively, and the back yoke 5 is further provided with a back yoke 5. It is laminated on the surface of.

According to the DC reactor of the prior art 2 constructed as described above, the coil magnetic flux 7 generated by the coil 6 circulates inside the yoke without completely penetrating the inside of the permanent magnet 4. The demagnetization of 4 can be suppressed.

[0007]

However, in the DC reactor of the prior art 2, the permanent magnet 4 is in close contact with the respective side surfaces of the C-shaped layer core 1 and the T-shaped layer core 2 in such a manner as to cover the magnetic gap 3. Therefore, it is by no means preferable as a method for suppressing the demagnetization of the permanent magnet 4. That is, in a portion of the permanent magnet 4 close to the magnetic gap 3, as described in detail below, a decrease in the magnetic characteristics of the permanent magnet 4 due to a temperature rise and a leakage magnetic flux of the coil magnetic flux 7 from the magnetic gap 3 are combined. Therefore, there is a possibility that the magnetic field may be significantly demagnetized.

Here, the deterioration of the magnetic properties of the permanent magnet 4 due to the temperature rise means that the demagnetization curve, which is a typical magnetic property of the ferrite magnet material or the rare earth magnet material forming the permanent magnet 4, has a negative temperature coefficient. And a phenomenon in which the magnetic characteristics deteriorate with increasing temperature. FIG. 10 illustrates this phenomenon, and shows the temperature change of the demagnetization curve in NEOMAX (registered trademark) -37H manufactured by Sumitomo Special Metals Co., Ltd., which is an example of a rare earth magnet. Generally, NEOMAX
In the case of a permanent magnet having large energy density and magnetic flux density such as (registered trademark) -37H, the coercive force Hc and the residual magnetic flux density Br are remarkably reduced and the permanent magnet 4 is demagnetized as the temperature rises. It will be in an easy state.

On the other hand, the coil magnetic flux 7 from the magnetic gap 3
Part of the leakage magnetic flux passes through the portion of the permanent magnet 4 adjacent to the magnetic gap 3 and acts to demagnetize the adjacent portion. Moreover, the permanent magnet 4 has a function of causing an eddy current loss in a portion close to the magnetic gap 3 and raising the temperature of the adjacent portion, which is a major factor for demagnetizing the adjacent portion.

As described above, in the DC reactor of Prior Art 2, when the portion of the permanent magnet 4 close to the magnetic gap 3 is easily demagnetized due to the temperature rise, the portion close to the coil magnetic flux 7 There is a problem that it is demagnetized by the leakage magnetic flux.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a DC reactor capable of suppressing demagnetization of a permanent magnet due to leakage flux of a coil magnetic flux.

[0012]

To achieve the above object, a DC reactor according to the present invention comprises a closed magnetic circuit type main yoke which forms a closed magnetic circuit via a main magnetic gap which is a magnetic gap. A coil for generating a magnetic flux in the closed magnetic circuit,
In a DC reactor provided with a permanent magnet that applies a bias magnetic field to the magnetic flux generated by the coil, the permanent magnet is arranged in a manner to straddle the main magnetic gap and separate from the main yoke, and The permanent magnet is connected to the main yoke through the portions that are at both ends with the main magnetic gap interposed therebetween.

According to the present invention, since the permanent magnet is arranged so as to straddle the main magnetic gap and be separated from the main yoke, a coil which leaks from the main magnetic gap and passes through the permanent magnet. The amount of leakage flux of the magnetic flux is reduced and the temperature rise of the permanent magnet due to the eddy current loss accompanying the leakage flux is suppressed.

In the DC reactor according to the next invention,
In the above invention, the connection area between the main yoke and the permanent magnet is smaller than the facing area of the main magnetic gap.

According to the present invention, since the connecting area between the main yoke and the permanent magnet is smaller than the facing area of the main magnetic gap, the magnetic resistance of the magnetic path leading to the permanent magnet is closer to the main magnetic gap. It becomes larger than the magnetic resistance of the magnetic path that leads to it.

In the DC reactor according to the next invention,
In the above invention, the main yoke is provided with a corner portion, the main magnetic gap is formed in the vicinity of the corner portion, and the permanent magnet is arranged on an outer surface of the corner portion of the main yoke. Is characterized by.

According to this invention, since the magnetic path leading to the permanent magnet is larger than the magnetic path leading to the main magnetic gap, the magnetic resistance in the magnetic path leading to the permanent magnet is the magnetic path leading to the main magnetic gap. Greater than the reluctance in the path.

In the DC reactor according to the next invention,
In the above invention, a gap is secured between the main yoke and the permanent magnet that is 1/2 or more of a separation distance of the main magnetic gap.

According to the present invention, the gap between the main yoke and the permanent magnet is 1/2 or more of the distance of the main magnetic gap.

In the DC reactor according to the next invention, in the above invention, an auxiliary yoke is projected from the main yoke, and the permanent magnet is connected to the main yoke via the auxiliary yoke. Characterize.

According to the present invention, since the auxiliary yoke is projected from the main yoke and is connected to the main yoke via the auxiliary yoke, a flat permanent magnet can be applied. .

The DC reactor according to the next invention is such that, in the above invention, the connection area between the auxiliary yoke and the permanent magnet changes when the gap between the main yoke and the permanent magnet is changed. The permanent magnet is connected to the auxiliary yoke.

According to the present invention, the connection area between the auxiliary yoke and the permanent magnet is changed by changing the gap between the main yoke and the permanent magnet.

The DC reactor according to the next invention is the same as the above invention, except that the main yoke is constituted by a combination of one or more cores using a laminated core or a soft magnetic ferrite bulk core, or a continuous molded body. Characterize.

According to the present invention, the main yoke is composed of a laminated core, a combination of one or more cores using a soft magnetic ferrite bulk core, or a continuous molded body.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a DC reactor according to the present invention will be described in detail below with reference to the accompanying drawings.

Embodiment 1. 1A and 1B show a DC reactor according to the first embodiment. FIG. 1A is a plan view and FIG. 1B is a sectional side view. The DC reactor is provided in, for example, an inverter circuit and suppresses the pulsation of DC current in the inverter circuit.

In the DC reactor shown in FIG. 1, an E-shaped forming layer core 10 and an I-shaped forming layer core 11 formed by laminating thin sheets of soft magnetic material are vertically combined to form a main yoke.

The E-shaped forming layer core 10 has a substantially rectangular parallelepiped central leg 10C, a right leg 10R and a left leg 10L.
One end of the rectangular parallelepiped portion is orthogonally connected to the center of the rectangular parallelepiped portion and the left and right ends thereof are integrally formed. On the other hand, the I-shaped forming layer iron core 11 has a substantially rectangular parallelepiped shape.

Since the right leg 10R and the left leg 10L of the E-shaped formation core 10 are formed shorter than the central leg 10C, the bottom surface of the central leg 10C of the E-shaped formation core 10 is formed into the I-shaped formation layer. If connected to the iron core 11, the right leg 10R and I
A main magnetic gap G is formed between the character forming layer core 11 and between the left leg 10L and the I-character forming layer core 11, respectively. In this way, the DC reactor constitutes a substantially leg-shaped three-leg iron core including the main magnetic gaps G provided on the left and right sides of the main yoke in the magnetic circuit.

When assembling the main yoke, a non-magnetic insulating plate is inserted between the mating surfaces of the main magnetic gap G, specifically, the surfaces facing each other and constituting the main magnetic gap G. The main magnetic gap G may be retained. Further, a vibration damping material may be inserted between the mating surfaces of the central leg 10C of the E-shaped forming layer core 10 and the I-shaped forming layer core 11 so as to suppress electromagnetic vibration between them.

In the DC reactor shown in FIG. 1, the coil 12 is wound around the central leg 10C of the E-shaped layer core 10 while the E-shaped layer core 10 and the I-shaped layer core 11 are arranged.
Are provided with protruding auxiliary yokes 13 and 14 (auxiliary yokes), respectively.

The coil 12 generates a coil magnetic flux Φc when a current is passed inside the coil 12. In the coil 12, a current is made to flow inside the coil 12 so that the coil magnetic flux Φc in the main yoke opposes a bias magnetic flux Φm generated by a permanent magnet 15 described later.

The projecting auxiliary yokes 13 and 14 are formed by sandwiching the main magnetic gap G above and below to form the main yoke. The E-shaped forming layer side surfaces of the right leg 10R and the left leg 10L of the iron core 10 and the I-shaped forming layer. This is a portion protruding from the side surface of the iron core 11. The projecting auxiliary yokes 13 and 14 can be formed by stacking thin plates of a soft magnetic material punched integrally with the main yoke, for example. Here, the protruding auxiliary yokes 13 and 14 facing each other
Is smaller than the facing area Ag between the right leg 10R and the left leg 10L of the E-shaped forming layer core 10 forming the main magnetic gap G and the I-shaped forming layer core 11.

A permanent magnet 15 is arranged between the protruding auxiliary yokes 13 and 14 so as to straddle the main magnetic gap G. The permanent magnet 15 biases the coil magnetic flux Φc generated by the coil 12, and has a flat plate shape. The permanent magnet 15 is inserted laterally between the protruding auxiliary yokes 13 and 14, and is magnetized antiparallel to the traveling direction of the coil magnetic flux Φc passing through the main magnetic gap G. In this state, they are connected to the projecting auxiliary yokes 13 and 14, respectively.

Here, the permanent magnet 15 is magnetized so that both end faces in the longitudinal direction of the permanent magnet 15 are magnetic pole faces, and are inserted between the protruding auxiliary yokes 13 and 14, respectively. In addition, the magnetic pole surface serves as a contact surface with the protruding auxiliary yokes 13 and 14. This permanent magnet 15
In the above, the length in the longitudinal direction of the longitudinal section is the length Hm in the magnetizing direction, and the ratio of the magnetic pole cross-sectional area to the length Hm in the magnetizing direction is made small. However, the permanent magnet 15
The cross-sectional area of the magnetic pole is set to be larger than the cross-sectional area assumed to be necessary from the desired amount of the generated bias magnetic field. When this permanent magnet 15 is inserted between the protruding auxiliary yokes 13 and 14, the center line of the main magnetic gap G and the magnetic pole neutral line Cm of the permanent magnet 15, that is, the position where the magnetic pole is reversed, coincide. I am doing it.

Between the permanent magnet 15 and the main yoke, that is, the E-shaped forming layer core 10 and the I-shaped forming layer core 11,
A gap adjusting spacer 16 having a thickness Ls is inserted.

The gap adjusting spacer 16 is composed of an insulating plate which is non-magnetic and has a thermal conductivity smaller than that of iron, and is provided between the permanent magnet 15 and the E-shaped forming layer core 10 and the I-shaped forming layer core 11. It defines the gap.

As a result, in the DC reactor according to the first embodiment, the permanent magnet 15 and the E-shaped forming layer cores 10 and I are formed.
A magnetic gap (hereinafter, magnetic gap Gs) having a separation distance Ls from each other does not come into close contact with the character forming layer iron core 11.
Will be secured). Here, the separation distance Ls of the magnetic gap Gs is preferably set to be 1/2 or more of the separation distance Lg of the main magnetic gap G. That is, if the separation distance Ls of the magnetic gap Gs is smaller than that, the amount of leakage flux of the coil magnetic flux Φc, which will be described later, locally penetrates the permanent magnet 15, which is not preferable.

In the first embodiment configured as described above, when the coil 12 is excited by the pulsating DC current,
As illustrated by the solid line in FIG. 1B, the coil magnetic flux Φc created by the coil 12 is the central leg 10 of the E-shaped forming layer core 10.
It branches from C to the left and right, flows through the inside of the right leg 10R and the left leg 10L, passes through the main magnetic gap G, passes through the I-shaped forming layer core 11, and then to the central leg 10C of the E-shaped forming layer core 10. To return. On the other hand, the bias magnetic flux Φm generated by the permanent magnet 15 is, as shown by a broken line in FIG. 1B, via the protruding auxiliary yoke 13 the right leg 10 of the E-shaped forming layer iron core 10.
After flowing into R and the left leg 10L, E-shaped formation core 1
It returns to the permanent magnet 15 via the center leg 10C of 0, the I-shaped forming layer iron core 11, and the protruding auxiliary yoke 14.

Here, in the first embodiment, the separation distance Lg of the main magnetic gap G <the length H of the permanent magnet in the magnetizing direction is set.
m and the facing area Ag in the main magnetic gap> the facing area As between the protruding auxiliary yokes 13 and 14 is As. Therefore, in the parallel magnetic path of the magnetic paths on the E-shaped forming layer core 10 and the I-shaped forming layer core 11 side and the magnetic paths on the protruding auxiliary yokes 13 and 14 side, the protruding auxiliary yokes 13 and 1 are arranged in parallel.
Since the magnetic path on the side of 4 has a larger magnetic resistance than the magnetic paths on the side of the E-shaped forming layer iron core 10 and the I-shaped forming layer iron core 11, the situation in which the coil magnetic flux Φc bypasses and flows into the permanent magnet 15 is prevented. can do. In addition, since the projecting auxiliary yokes 13 and 14 are provided at the portions serving as the corners of the left and right ends of the I-shaped layer iron core 11 where the coil magnetic flux Φc bends at a right angle, that is, the portions on the outer peripheral side of the magnetic path, Coil magnetic flux Φ due to the difference in magnetic resistance due to the difference between the inner and outer circumferences of the magnetic path
The effect of suppressing c from passing through the protruding auxiliary yokes 13 and 14 is high.

As a result, the coil 12 is wound around the coil E
In the central leg 10C of the character-forming layer core 10, the coil 1
While the coil magnetic flux Φc due to 2 and the bias magnetic flux Φm due to the permanent magnet 15 flow in opposition, the coil magnetic flux Φc at the upper and lower portions with the main magnetic gap G interposed therebetween.
And the bias magnetic flux Φm are surely branched. Therefore, in the central leg 10C of the E-shaped forming layer core 10,
The coil 1 is generated by the bias magnetic flux Φm generated by the permanent magnet 15.
The coil magnetic flux Φc due to 2 is biased in the opposite direction, and the coil magnetic flux Φc is located above and below the main magnetic gap G, so that the coil magnetic flux Φc is protruded.
It is possible to suppress the demagnetization effect on the permanent magnet 15 such as passing through the permanent magnet 15 via the magnets 3 and 14.

On the other hand, since the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, that is, the E-shaped forming layer core 10 and the I-shaped forming core 11, the coil magnetic flux Φc from the main magnetic gap G. It is possible to reduce the amount of leakage flux passing through the portion of the permanent magnet 15 that is close to the main magnetic gap G.

FIG. 2 exemplifies the result of the magnetic field analysis that supports this, FIG. 2 (a) shows the model to be subjected to the magnetic field analysis, and FIG. 2 (b) shows the analysis result by calculation. This magnetic field analysis is performed in the shape of a letter 3 without the permanent magnet 15.
A non-linear static magnetic field analysis is performed in the 1/4 region by taking the leg iron core as a model and considering the symmetry of the iron core structure. In this analysis, the number of turns of the coil is 9 turns, the energizing current is 420 A, which is 3 times the rated current in consideration of the exciting current, the separation distance Lg of the main magnetic gap G is 1.25 mm, and the main yoke is a non-directional electromagnetic. It is set as being constituted by a laminated core of steel plate 50A470. Further, in FIG. 2A, the dimensions L1, L2, L3 and L4 of the main yoke are 45 mm,
The leakage magnetic flux density of the coil magnetic flux from the main magnetic gap G is calculated for the space of the square mesh surrounded by the circles of 60 mm, 48 mm and 11 mm.

In FIG. 2B, the horizontal axis of the graph is the distance in the Z direction from the magnetic pole neutral line Cm of the magnet (the magnetic pole neutral line Cm coincides with the center line of the main magnetic gap as described above). And the vertical axis of the graph is the leakage magnetic flux density Bx of the X-direction component
And the leakage magnetic flux density Bz of the Z direction component are plotted. Here, the leakage magnetic flux density Bx and the leakage magnetic flux density Bz
Plots the results of calculations in three cases of 50 μm, 0.5 mm, and 1 mm, with the distance Lx in the X direction indicating the distance separated from the side surface of the main yoke as an parameter.

From the analysis result shown in FIG. 2B, when the distance Lx in the X direction from the side surface of the main yoke is 50 μm, the leakage magnetic flux density Bx and the leakage magnetic flux density Bz in the vicinity of the main magnetic gap G are both Is also large, showing a value around 0.7T. On the other hand, the distance Lx in the X direction is the main magnetic gap G.
When the separation distance Lg is 0.5 mm, which is 1/2 or less than 1.25 mm, the leakage magnetic flux density Bx and the leakage magnetic flux density Bz in the vicinity of the main magnetic gap are 2 of the previous values.
It is reduced to / 3 or less. That is, by increasing the X-direction distance Lx from the side surface of the main yoke, the leakage magnetic flux from the main magnetic gap G is significantly reduced.

As a result, in the DC reactor according to the first embodiment, the magnetic gap Gs is provided, and the separation distance Ls of the magnetic gap Gs is preferably 1/2 or more of the separation distance Lg of the main magnetic gap G. As a result, the leakage magnetic flux of the coil magnetic flux Φc passing through the portion of the permanent magnet 15 near the main magnetic gap G is significantly reduced. In addition, the eddy current loss due to the leakage flux of the coil magnetic flux Φc is significantly reduced in the portion of the permanent magnet 15 close to the main magnetic gap G. It is possible to suppress the temperature rise in the adjacent portion of.

Therefore, according to the DC reactor of the first embodiment, it is possible to suppress the temperature rise in the portion of the permanent magnet 15 which is close to the main magnetic gap G, and the coil magnetic flux Φc.
Since it is possible to reduce the amount of the leakage magnetic flux passing through the adjacent portion, it is possible to suppress demagnetization of the portion of the permanent magnet 15 near the main magnetic gap G. As a result, according to the first embodiment, demagnetization of the permanent magnet 15 due to the leakage magnetic flux of the coil magnetic flux Φc can be suppressed.

On the other hand, between the side surface of the permanent magnet 15 and the side surfaces of the main yoke, that is, the E-shaped forming layer core 10 and the I-shaped forming layer core 11, a non-magnetic insulating plate having a thermal conductivity smaller than that of iron. It is filled with the gap adjusting spacer 16 or the air layer. As a result, the heat generated in the E-shaped forming layer core 10 and the I-shaped forming layer iron core 11 caused by the iron loss and the heat generated in the coil 12 caused by the copper loss are mainly butt-matched with the protruding auxiliary yokes 13 and 14. The heat is transmitted through the surface, that is, the contact surface. Here, in the DC reactor according to the first embodiment, the permanent magnets 15 magnetized so that both end faces in the longitudinal direction in the longitudinal section are magnetic pole faces are inserted between the protruding auxiliary yokes 13 and 14. The magnetic pole surface is configured to be an abutting surface with the protruding auxiliary yokes 13 and 14.

Therefore, according to the DC reactor of the first embodiment, the contact surface area is designed to be smaller than the case where the side surface of the permanent magnet 15 is used as the contact surface, and heat conduction through the contact surface is suppressed. You can Therefore, the permanent magnet 15
It becomes possible to suppress the performance deterioration of the DC reactor due to the temperature rise, and as a result, it becomes possible to maintain the LI characteristic of the DC reactor as desired as possible.

Further, according to the DC reactor of the first embodiment, since the ratio of the magnetic pole cross-sectional area to the length Hm of the permanent magnet 15 in the magnetizing direction is made small, the operating point of the permanent magnet 15 is set high. As a result, more stable magnet characteristics can be secured against demagnetization factors such as the external magnetic field and the temperature rise of the permanent magnet 15.

Furthermore, according to the DC reactor of the first embodiment, since the demagnetization performance for the permanent magnet 15 is improved by the above-mentioned configuration, it is possible to use an inexpensive permanent magnet material having a small coercive force. And as a result,
It is possible to reduce the manufacturing cost of the DC reactor.

On the other hand, in the DC reactor according to the first embodiment, the permanent magnet 15 is inserted laterally between the projecting auxiliary yokes 13 and 14, and the magnetic pole cross-sectional area of the permanent magnet 15 is increased. Is taken to be larger than the cross-sectional area assumed to be necessary from the desired amount of generated bias magnetic field.

Thus, the abutting area Am between the permanent magnet 15 and the protruding auxiliary yokes 13 and 14, that is, the connection area can be increased or decreased to increase or decrease the bias magnetic flux Φm at any time regardless of the coil magnetic flux Φc. Therefore, as illustrated in FIG. 3, the operating range of the inductance L of the DC reactor with respect to the exciting current I can be adjusted at any time. For example, the magnetic gap length Ls is Ls
When there is a relationship of B <LsA <LsC, LsA to Ls
If it is changed to B and the magnetic gap length Ls is reduced,
The LI characteristic shifts to the high current side, that is, to the positive side of the horizontal axis, and conversely, if the magnetic gap length Ls is increased by changing from LsA to LsC, the LI characteristic shifts to the low current side. .

Therefore, according to the DC reactor of the first embodiment, by changing the abutting area Am of the permanent magnet 15 and the protruding auxiliary yokes 13 and 14, even after the DC reactor is assembled. It is possible to obtain a desired LI characteristic by correcting the deviation with respect to the design bias magnetic flux due to the machining error, the variation in material characteristics, and the like. Note that if the magnetic gap length Ls is made too narrow, the inductance value at low current may decrease, so it is necessary to make the change within an allowable range.

Embodiment 2. FIG. 4 is a cross-sectional side view showing the DC reactor according to the second embodiment. In the second embodiment, the C-shaped layer iron core 20 and the T-shaped layer iron core 21 are vertically combined to form a main yoke, and like the first embodiment described above, a substantially date-shaped three-leg iron core type DC It constitutes a reactor.

The C-shaped layer iron core 20 has a structure in which one ends of substantially parallelepiped right leg 20R and left leg 20L, which are in a parallel relationship, are orthogonally connected to the left and right ends of the rectangular parallelepiped portion. . On the other hand, the T-shaped forming layer core 21 has a structure in which a rectangular parallelepiped leg portion 21C is orthogonally connected to the center of the rectangular parallelepiped portion to be integrated.

In the DC reactor according to the second embodiment, the coil 22 is wound around the leg portion 21C of the T-shaped formation layer iron core 21, while the C-shaped formation layer iron core 20 and the T-shaped formation layer iron core 2 are provided.
A main magnetic gap G is provided between the two. Further, in the DC reactor according to the second embodiment, the protruding auxiliary yoke 2 is provided at a portion located above and below the main magnetic gap G in the C-shaped forming layer core 20 and the T-shaped forming layer core 21.
3 and 24 are provided, and these protruding auxiliary yokes 23 and 2 are provided.
A permanent magnet 15 is inserted and connected between the four. Except for these, the DC reactor of the second embodiment has the same assembly configuration and operation as those of the first embodiment described above, and therefore, the same reference numerals are given and detailed description thereof is omitted.

According to the DC reactor of the second embodiment, similar to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the magnetic gap Gs is provided.
The separation distance Ls of the main magnetic gap G is 1
/ 2 or more. Therefore, the permanent magnet 15
It is possible to suppress a temperature rise due to an eddy current loss in a portion of the permanent magnet 15 close to the main magnetic gap G, and reduce the amount of leakage flux of the coil magnetic flux Φc passing through a portion of the permanent magnet 15 close to the main magnetic gap G. As a result, the permanent magnet 1
Since it is possible to suppress demagnetization of the portion of the magnetic field near the main magnetic gap G in 5, the demagnetization of the permanent magnet 15 due to the leakage flux of the coil magnetic flux Φc can be suppressed according to the second embodiment. .

Further, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 through the auxiliary yoke, maintain the LI characteristic of the DC reactor as desired as possible, and prevent demagnetization factors. It is possible to secure more stable magnet characteristics, to use less expensive permanent magnet materials, and to correct deviations with respect to design bias magnetic flux to obtain desired LI characteristics. It is similar to the first embodiment.

Embodiment 3. FIG. 5 is a cross-sectional side view showing a DC reactor according to the third embodiment. In the third embodiment, the C-shaped forming layer iron core 30 and the I-shaped forming layer iron core 31 are vertically combined to form a main yoke, and a substantially square shape 2
It constitutes a leg core type DC reactor.

The C-shaped forming layer core 30 has a structure in which one ends of the right leg 30R and the left leg 30L, which are in a parallel relationship and which are substantially in the shape of a rectangular parallelepiped, are connected orthogonally to the left and right ends of the rectangular parallelepiped portion. . The I-shaped forming layer core 31 has a rectangular parallelepiped shape.

In the DC reactor according to the third embodiment, the coil 32 is wound around the I-shaped forming layer iron core 31, while C
A main magnetic gap G is provided between the letter-forming layer core 30 and the I-shaped layer core 31. In addition, in the DC reactor of the third embodiment, the protruding auxiliary yokes 33 and 34 are provided in the upper and lower portions of the C-shaped formation core 30 and the I-shaped formation core 31 with the main magnetic gap G interposed therebetween. The permanent magnet 15 is inserted and connected between the protruding auxiliary yokes 33 and 34. Except for these, the DC reactor of the third embodiment has the same assembly configuration and operation as those of the first embodiment described above, and therefore, the same reference numerals are given and detailed description thereof is omitted.

According to the DC reactor of the third embodiment, similar to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the magnetic gap Gs is provided.
The separation distance Ls of the main magnetic gap G is 1
/ 2 or more. Therefore, the permanent magnet 15
It is possible to suppress a temperature rise due to an eddy current loss in a portion of the permanent magnet 15 close to the main magnetic gap G, and reduce the amount of leakage flux of the coil magnetic flux Φc passing through a portion of the permanent magnet 15 close to the main magnetic gap G. As a result, the permanent magnet 1
Since it is possible to suppress demagnetization of the portion of the magnetic field near the main magnetic gap G in 5, the demagnetization of the permanent magnet 15 due to the leakage flux of the coil magnetic flux Φc can be suppressed according to the third embodiment. .

Further, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 via the auxiliary yoke, to maintain the LI characteristic of the DC reactor as desired as possible, and to prevent demagnetization factors. It is possible to secure more stable magnet characteristics, to use less expensive permanent magnet materials, and to correct deviations with respect to design bias magnetic flux to obtain desired LI characteristics. It is similar to the first embodiment.

In addition to the effects described above, according to the third embodiment, the mating surface of the main magnetic gap G and the mating surface of the main yoke at the time of assembly can be used together, so that the mating surface is reduced. At the same time, it becomes possible to reduce the manufacturing cost by eliminating the need for a vibration isolator inserted between the mating surfaces of the main yoke.

Fourth Embodiment FIG. 6 is a sectional side view showing a DC reactor according to the fourth embodiment. In the fourth embodiment, the C-shaped layer cores 40 and 41 are combined to the left and right to form a main yoke, and a substantially square V-shaped two-leg iron core type DC reactor is configured.

The C-shaped forming cores 40, 41 are substantially rectangular parallelepiped right legs 40R, 41R and a left leg 40 in a parallel relationship.
One end of L, 41L is left and right of the rectangular parallelepiped part (up and down in FIG. 6)
It has a structure in which both ends are connected orthogonally and integrated.

In the DC reactor according to the fourth embodiment, C
A coil 42 is wound around each of the character-forming layer cores 40 and 41, while a main magnetic gap G is provided between the C-character forming cores 40 and 41. Further, in the DC reactor according to the fourth embodiment, the C-shaped formation cores 40, 4 are used.
1, projecting auxiliary yokes 43, 44 are provided in the upper and lower portions of the main magnetic gap G, and the permanent magnet 15 is inserted and connected between the projecting auxiliary yokes 43, 44. . Except for these, the DC reactor of the fourth embodiment has the same assembly configuration and operation as those of the first embodiment described above, and therefore, the same reference numerals are given and detailed description thereof is omitted.

According to the DC reactor of the fourth embodiment, similar to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the magnetic gap Gs is provided.
The separation distance Ls of the main magnetic gap G is 1
/ 2 or more. Therefore, the permanent magnet 15
It is possible to suppress a temperature rise due to an eddy current loss in a portion of the permanent magnet 15 close to the main magnetic gap G, and reduce the amount of leakage flux of the coil magnetic flux Φc passing through a portion of the permanent magnet 15 close to the main magnetic gap G. As a result, the permanent magnet 1
Since it is possible to suppress demagnetization in the portion of the magnetic field near the main magnetic gap G in 5, the demagnetization of the permanent magnet 15 due to the leakage magnetic flux of the coil magnetic flux Φc can be suppressed according to the fourth embodiment. .

Further, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 through the auxiliary yoke, maintain the LI characteristic of the DC reactor as desired as possible, and prevent demagnetization factors. It is possible to secure more stable magnet characteristics, to use less expensive permanent magnet materials, and to correct deviations with respect to design bias magnetic flux to obtain desired LI characteristics. It is similar to the first embodiment.

In addition to the effects described above, according to the fourth embodiment, the mating surface of the main magnetic gap G and the mating surface of the main yoke during assembly can be used in the same manner as in the third embodiment. As a result, the number of mating surfaces is reduced, and a vibration damping material to be inserted between the mating surfaces of the main yoke is not required. Therefore, the manufacturing cost can be reduced.

Embodiment 5. FIG. 7 is a sectional side view showing a DC reactor according to the fifth embodiment. In the fifth embodiment, the E-shaped forming layer cores 50 and 51 are vertically combined to form a main yoke, thereby forming a substantially date-shaped three-leg core type DC reactor.

The E-shaped forming cores 50 and 51 are composed of substantially rectangular parallelepiped central legs 50C and 51C, and a right leg 50R, which are arranged in parallel.
One end of 51R and the left legs 50L and 51L are orthogonally connected to the center of the rectangular parallelepiped portion and the left and right ends thereof so as to be integrated.

In the DC reactor according to the fifth embodiment, E
While the coil 52 is wound around the central legs 50C and 51C of the character forming cores 50 and 51, the main magnetic gap G is provided between the E character forming cores 50 and 51. In addition, in the DC reactor according to the fifth embodiment,
Protruding auxiliary yokes 53, 54 are provided in the upper and lower portions of the E-shaped forming cores 50, 51 with the main magnetic gap G interposed therebetween.
The permanent magnet 15 is inserted and connected between the protruding auxiliary yokes 53 and 54. Except for these, in the DC reactor of the fifth embodiment, the assembly configuration and operation are the same as those of the above-described first embodiment, and therefore, the same reference numerals are given and detailed description thereof is omitted.

According to the DC reactor of the fifth embodiment, as in the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the magnetic gap Gs is provided.
The separation distance Ls of the main magnetic gap G is 1
/ 2 or more. Therefore, the permanent magnet 15
It is possible to suppress a temperature rise due to an eddy current loss in a portion of the permanent magnet 15 close to the main magnetic gap G, and reduce the amount of leakage flux of the coil magnetic flux Φc passing through a portion of the permanent magnet 15 close to the main magnetic gap G. As a result, the permanent magnet 1
Since it is possible to suppress demagnetization of the portion of the magnetic field near the main magnetic gap G in No. 5, according to the fifth embodiment, it is possible to suppress demagnetization of the permanent magnet 15 due to the leakage magnetic flux of the coil magnetic flux Φc. .

Further, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 through the auxiliary yoke, maintain the LI characteristic of the DC reactor as desired as possible, and prevent demagnetization factors. It is possible to secure more stable magnet characteristics, to use less expensive permanent magnet materials, and to correct deviations with respect to design bias magnetic flux to obtain desired LI characteristics. It is similar to the first embodiment.

In the first to fifth embodiments described above, an example in which the main yokes including the protruding auxiliary yokes are all composed of a layered core is shown. However, the core yoke is composed of a soft magnetic ferrite having a high specific resistance. Of course, the same effect can be obtained.

Sixth Embodiment FIG. 8 shows a DC reactor according to the sixth embodiment. FIG. 8 (a) is a plan development view of a main yoke and FIG. 8 (b) is a sectional side view. In the sixth embodiment, one H-shaped forming layer core 60 is used as a main yoke, and a substantially date-shaped three-leg core type DC reactor is configured.

The H-shaped forming layer core 60 has an upper arm portion 60A and a lower arm portion 60B which are located above and below the center leg 60C in FIG. 8 (a), and further, these upper arm portions 60A.
And thin-walled connecting portions 60 on the left and right ends of the bottom arm portion 60B.
Tip portions 60a and 60b are provided via a'and 60b ', respectively. The H-shaped forming core 60 is manufactured as an integral structure.

The tip end portions 60a and 60b are provided with protruding auxiliary yokes 63 and 64, respectively, so that they have a positional relationship facing each other when the main yoke is assembled. When the main yoke is assembled, the tips 60a and 60b are
The portion forming the right leg 60R and the left leg 60L of the character forming layer iron core 60 is formed.

In the DC reactor according to the sixth embodiment, H
After the coil 62 is wound around the central leg 60C of the character-forming layer iron core 60, the thin connecting portions 60a 'and 60b' are bent inward and the joint butting surfaces Ac are closed to close the main magnetic gap G. After forming and holding the main magnetic gap G by a non-magnetic insulating plate, the permanent magnet 15 is further inserted and connected between the projecting auxiliary yokes 63 and 64, and then a substantially date-shaped tripod core is formed. A type DC reactor is configured.

The operation of the sixth embodiment is the same as that of the above-described fifth embodiment except for the main assembly structure described above, and therefore, the same reference numerals are given and detailed description thereof will be omitted.

According to the DC reactor of the sixth embodiment, similar to the first embodiment, the magnetic gap Gs is provided between the permanent magnet 15 and the main yoke, and the magnetic gap Gs is provided.
The separation distance Ls of the main magnetic gap G is 1
/ 2 or more. Therefore, the permanent magnet 15
It is possible to suppress a temperature rise due to an eddy current loss in a portion of the permanent magnet 15 close to the main magnetic gap G, and reduce the amount of leakage flux of the coil magnetic flux Φc passing through a portion of the permanent magnet 15 close to the main magnetic gap G. As a result, the permanent magnet 1
Since it is possible to suppress demagnetization of the portion of the magnetic field near the main magnetic gap G in 5, the demagnetization of the permanent magnet 15 due to the leakage flux of the coil magnetic flux Φc can be suppressed according to the sixth embodiment. .

Further, it is possible to prevent the coil magnetic flux Φc from passing through the permanent magnet 15 through the auxiliary yoke, maintain the LI characteristic of the DC reactor as desired as possible, and prevent demagnetization factors. It is possible to secure more stable magnet characteristics, to use less expensive permanent magnet materials, and to correct deviations with respect to design bias magnetic flux to obtain desired LI characteristics. It is similar to the first embodiment.

In addition to the effects described above, according to the DC reactor of the sixth embodiment, it is not necessary to provide a butt face on the central leg 60C of the H-shaped forming layer core 60 around which the coil 62 is wound, and the butt face is not required. Since there is no work gap generated due to the surface, it is possible to suppress a decrease in the inductance L of the DC reactor due to the work gap, electromagnetic vibration, and the like.

Further, according to the DC reactor of the sixth embodiment, since the main yoke is an integral structure through the thin connecting portions 60a 'and 60b', the joining butting surface A
Electromagnetic vibration via c can be suppressed.

[0088]

As described above, according to the present invention, since the permanent magnets are arranged so as to straddle the main magnetic gap and be separated from the main yoke, leakage from the main magnetic gap occurs. The amount of leakage flux of the coil magnetic flux passing through the permanent magnet is reduced, and the temperature rise of the permanent magnet due to the eddy current loss accompanying the leakage magnetic flux is suppressed. Demagnetization can be suppressed.

According to the next invention, since the connecting area between the main yoke and the permanent magnet is smaller than the facing area of the main magnetic gap, the magnetic resistance of the magnetic path leading to the permanent magnet is smaller than the main magnetic gap. Since it is larger than the magnetic resistance of the magnetic path leading to the coil, it is possible to prevent the coil magnetic flux from passing through the permanent magnet through the connecting surface between the main yoke and the permanent magnet.

According to the next invention, since the magnetic path leading to the permanent magnet is larger than the magnetic path leading to the main magnetic gap, the magnetic resistance in the magnetic path leading to the permanent magnet leads to the main magnetic gap. It is larger than the magnetic resistance in the magnetic path. Therefore, it is possible to more reliably prevent the coil magnetic flux from passing through the permanent magnet through the connection surface between the main yoke and the permanent magnet.

According to the next invention, since the gap which is more than 1/2 of the separation distance of the main magnetic gap is secured between the main yoke and the permanent magnet, the permanent magnet due to the leakage flux of the coil magnetic flux is secured. The demagnetization can be suppressed more reliably.

According to the next invention, since the auxiliary yoke is projected on the main yoke and the auxiliary yoke is connected to the main yoke, the flat permanent magnet can be applied. Become.

According to the next invention, the connection area between the auxiliary yoke and the permanent magnet can be changed by changing the gap between the main yoke and the permanent magnet. It becomes easy to obtain a desired LI characteristic by correcting the deviation with respect to the design bias magnetic flux due to the variation of the above.

According to the next invention, the main yoke is composed of a laminated core, a combination of one or more cores using a soft magnetic ferrite bulk core, or a continuous molded body.

[Brief description of drawings]

1A and 1B show a DC reactor that is Embodiment 1 of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a sectional side view.

2A and 2B show results of magnetic field analysis in the vicinity of a main magnetic gap, FIG. 2A is an explanatory diagram of a model that is a target of magnetic field analysis, and FIG. 2B is a diagram showing analysis results by calculation.

FIG. 3 is an explanatory diagram showing a relationship between a magnetic gap and an LI characteristic in the DC reactor according to the first embodiment.

FIG. 4 is a sectional side view of a DC reactor that is Embodiment 2 of the present invention.

FIG. 5 is a sectional side view of a DC reactor that is Embodiment 3 of the present invention.

FIG. 6 is a sectional side view of a DC reactor that is Embodiment 4 of the present invention.

FIG. 7 is a sectional side view of a DC reactor that is Embodiment 5 of the present invention.

8A and 8B show a DC reactor according to a sixth embodiment of the present invention, in which FIG. 8A is a plan development view of a main yoke, FIG.
Is a sectional side view.

FIG. 9 is a cross-sectional side view of a DC reactor that is prior art 2.

FIG. 10 is an explanatory diagram showing a temperature change of a demagnetization curve in a permanent magnet.

[Explanation of symbols]

10 E-shaped forming layer iron core, 10C central leg, 10R right leg, 10L left leg, 11 I-shaped forming layer iron core, 12 coils, 13, 14 protruding auxiliary yoke, 15 permanent magnet,
16 gap adjusting spacer, 20 C-shaped forming layer core, 20R right leg, 20L left leg, 21 T-shaped forming layer iron core, 21C leg part, 22 coil, 23, 24 protruding auxiliary yoke, 30 C-shaped forming layer iron core , 30R right leg, 30
L left leg, 31 I-shaped formation core, 32 coils, 3
3,34 Protruding auxiliary yoke, 40,41 C-shaped formation core, 42 coil, 43,44 Protruding auxiliary yoke, 5
0,51 E-shaped formation core, 50C, 51C central leg, 5
0R, 51R right leg, 50L, 51L left leg, 52 coil, 53, 54 protruding auxiliary yoke, 60 H-shaped forming core, 60A upper arm, 60B bottom arm, 60a, 60
b Tip part, 60a ', 60b' Thin connecting part, 60C
Central leg, 60R right leg, 60L left leg, 62 coil, 63, 64 protruding auxiliary yoke, Cm magnetic pole neutral wire,
G main magnetic gap, Gs magnetic gap, Φc coil magnetic flux, Φm bias magnetic flux.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Akita             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Akinori Nishihiro             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Akira Imanaka             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd.

Claims (7)

[Claims] 1. A main magnetic yoke of a closed magnetic circuit type that forms a closed magnetic circuit through a main magnetic gap that is a magnetic gap, a coil that generates a magnetic flux in the closed magnetic circuit, and a magnetic flux generated by the coil. A permanent magnet for applying a bias magnetic field to the main magnetic gap, the permanent magnet being arranged in a manner to be separated from the main yoke, and the both ends with the main magnetic gap sandwiched therebetween. A direct current reactor characterized in that the permanent magnet is connected to the main yoke via a portion that becomes. 2. The DC reactor according to claim 1, wherein the connection area between the main yoke and the permanent magnet is smaller than the facing area of the main magnetic gap. 3. A corner portion is provided in the main yoke, the main magnetic gap is formed in the vicinity of the corner portion, and the permanent magnet is arranged on an outer surface of the corner portion of the main yoke. The DC reactor according to claim 1 or 2, characterized in that. 4. A gap between the main yoke and the permanent magnet, which is 1/2 or more of a separation distance of the main magnetic gap, is secured. DC reactor described in one. 5. The main yoke is provided with an auxiliary yoke projecting therefrom, and the permanent magnet is connected to the main yoke via the auxiliary yoke. DC reactor described in one. 6. The permanent magnet is changed to the auxiliary yoke in such a manner that a connection area between the auxiliary yoke and the permanent magnet changes when a gap between the main yoke and the permanent magnet is changed. The DC reactor according to claim 5, wherein the DC reactor is connected. 7. The main yoke is constituted by a laminated core or a combination of one or more cores using a soft magnetic ferrite bulk core, or the main yoke is constituted by a continuous molded body. DC reactor described in one.