JP2008159832A - Reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor which prevents a leakage flux generating in a gap between a substantially U-shaped core block and an I character part from entering a coil, and reduces a loss of the core itself, thereby enhancing an efficiency. <P>SOLUTION: The reactor 1 comprises: a pair of parallel I character parts 5 assembled with two or more core blocks 5a, 5b, 5c; an annular core 2 composed of a pair of substantially U-shaped core blocks 4 connected to both ends of these I character parts; and a coil 3 wound on an outer periphery of the I character parts, respectively. Both the ends of the coil are disposed at a position apart at a distance of a thickness or more of a spacer 6 interposed between the I character part and the substantially U-shaped core block from a connection face of the substantially U-shaped core block. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reactor mounted on an electric vehicle such as a hybrid vehicle or a fuel cell vehicle.

  In recent years, automobiles that run by driving a motor with a DC power source such as a hybrid vehicle and a fuel cell vehicle have been developed due to environmental problems. These automobiles are equipped with a boost converter that boosts the voltage of a battery that is a DC power source. The step-up converter includes a reactor and a switching circuit.

  The reactor includes an annular core and a coil attached to the core. In a vehicle-mounted reactor, a pair of parallel I-shaped parts are configured by assembling two or more rectangular parallelepiped core blocks due to restrictions on mounting space, manufacturing method, and the like, and substantially U at both ends of these I-shaped parts. In many cases, a substantially elliptical annular core configured by connecting letter-shaped core blocks is employed. A gap is provided between the core blocks in order to adjust the inductance of the magnetic circuit, and a spacer made of a nonmagnetic material is inserted in the gap. By passing a current through the coil, an annular magnetic circuit is formed in the core.

JP2004-241475

  Since the spacer is made of a non-magnetic material, leakage magnetic flux is likely to be generated from the peripheral edge of the gap. When the leakage magnetic flux is generated, eddy current is generated in the coil and the core block, the loss is increased, and the energy conversion efficiency of the reactor is lowered. Moreover, the magnetic flux density in the core is unevenly distributed due to the leakage magnetic flux, and the vibration and noise of the core are induced.

  In particular, when the substantially oval annular core is employed, the direction of the magnetic flux is changed by 180 degrees along the U-shape of the substantially U-shaped core block. In the gap close to the U-shaped innermost part, the inner peripheral surface of the U-shaped core block is located close to the diagonally front of the inner peripheral edge of the gap, and therefore leakage toward the inner peripheral surface of the U-shaped core block. Magnetic flux increases.

  Moreover, when the coil is wound around the outer periphery of the gap, the leakage magnetic flux toward the inner peripheral surface of the substantially U-shaped core enters the coil as shown in FIG. Loss occurs.

  The present invention can prevent leakage magnetic flux generated in the gap between the substantially U-shaped core block and the I-shaped portion from entering the coil, and reduce the loss of the core itself to improve efficiency. The challenge is to provide a reactor that can be used.

  The invention described in claim 1 includes a pair of parallel I-shaped portions in which two or more core blocks are assembled, and a pair of substantially U-shaped core blocks connected to both ends of these I-shaped portions. A reactor comprising an annular core and a coil wound around the outer periphery of the I-shaped portion, wherein both ends of the coil are connected to the I-shaped portion and the substantially U-shaped portion from the connection surface of the substantially U-shaped core block. It is arranged at a position separated by a distance equal to or greater than the thickness of the spacer inserted between the letter-shaped core blocks.

  By adopting the above configuration, the coil is not positioned on the outer periphery of the gap between the substantially U-shaped core block and the I-shaped portion, and the leakage from the edge of the gap toward the substantially U-shaped core block. Magnetic flux does not easily enter the coil. In particular, the effect is great against leakage magnetic flux from the inner peripheral side edge of the I-shaped part toward the inner peripheral part of the substantially U-shaped core block. For this reason, the loss by the said leakage magnetic flux approaching into a coil can be prevented, and the fall of the efficiency of a reactor can be prevented.

  Further, as in the invention described in claim 2, by setting the distance to be twice or more the thickness of the spacer, it is possible to more effectively prevent the leakage magnetic flux from entering the coil.

  The invention described in claim 3 of the present application is such that the core cross-sectional area perpendicular to the magnetic flux direction of the substantially U-shaped core block is set larger than the core cross-sectional area of the I-shaped portion.

  The loss due to the core material increases in proportion to the square of the magnetic flux density. On the other hand, the magnetic flux density is inversely proportional to the core cross-sectional area perpendicular to the magnetic flux. The total core loss is the material loss multiplied by the total core volume. Therefore, theoretically, when the core cross-sectional area is increased and the magnetic flux density is lowered, the core loss is reduced. Since the substantially U-shaped core block is not wound with a coil, it is possible to reduce the loss without substantially changing the size and form of the conventional reactor even if the cross-sectional area is increased.

  However, when the cross-sectional area of the substantially U-shaped core block is increased, the leakage magnetic flux from the gap between the substantially U-shaped core block and the I-shaped portion toward the substantially U-shaped core block also increases. . In particular, the leakage magnetic flux from the inner peripheral edge of the I-shaped portion toward the inner peripheral surface of the U-shaped core block increases. For this reason, if a coil exists in the outer periphery of the gap as in the conventional case, the leakage magnetic flux enters the coil, and a very large loss occurs. Therefore, even if the cross-sectional area of the substantially U-shaped core block is increased, a sufficient effect cannot be obtained.

  In the present invention, both ends of the coil are separated from the connection surface of the substantially U-shaped core block by a distance equal to or greater than the thickness of the spacer inserted between the I-shaped portion and the substantially U-shaped core block. Therefore, the leakage magnetic flux does not enter the coil. Therefore, it is possible to prevent a loss due to the leakage magnetic flux entering the coil at the above portion, and the efficiency of the reactor can be improved.

  The cross-sectional area of the substantially U-shaped core block can be increased by expanding the cross-section of the substantially U-shaped core in four directions. The leakage magnetic flux toward the inner peripheral surface of the block increases. Therefore, as in the invention described in claim 4, it is preferable to increase the core cross-sectional area in a direction excluding the inner peripheral side of the substantially U-shaped core.

  In addition, when the cross-sectional area of the substantially U-shaped core block is increased with respect to the cross-sectional area of the I-shaped part, a substantially U-shaped connection is established between the substantially U-shaped core block and the I-shaped part. The part rises from the outer peripheral surface of the I-shaped part. For this reason, leakage magnetic flux from the I-shaped part toward the rising wall is also likely to occur.

  In order to avoid the above inconvenience, it is preferable to form the substantially U-shaped core block in a form in which the peripheral edge portion of the connection end surface with respect to the I-shaped portion is missing as in the invention described in claim 5.

  The form lacking the peripheral edge is not particularly limited. For example, it can be formed in a chamfered shape or can be formed to have a rounded shape. Moreover, it can also form in the step shape spaced apart from the edge part of the said coil.

  The present invention can be applied to a reactor including an annular core formed of various materials. For example, the present invention can be applied to a reactor including a core formed by compacting magnetic powder, a core obtained by stacking silicon steel plates, or a core configured by combining these materials.

  A core formed by compacting a magnetic powder has a high degree of freedom in shape and the like, and can form various types of cores. In particular, as in the invention described in claim 6, it is preferable to form at least the pair of substantially U-shaped cores from a compacted body of magnetic powder. As a result, the core cross-sectional area can be increased according to the dimensions and the magnetic circuit, and the loss can be reduced and the reactor performance can be improved without substantially changing the dimensions and form of the apparatus.

  The thickness of the spacer inserted between the I-shaped portion and the substantially U-shaped core block from both ends of the coil wound around the outer periphery of the I-shaped portion from the connection surface of the substantially U-shaped core block. By separating the distance more than this, leakage flux can be prevented from entering the coil, loss can be reduced, and the performance of the reactor can be improved.

  1 to 3 show a first embodiment of the present invention.

  As shown in FIG. 1 and FIG. 2, the reactor 1 includes an annular core 2 and a coil 3 attached around the core 2. Usually, a bobbin (not shown) for holding the coil 3 at a predetermined interval around the outer periphery of the core 2 is inserted between the core 2 and the coil 3 and the whole is formed into a box-shaped case. Contained.

  FIG. 2 shows a cross section taken along line II-II in FIG.

  In the present embodiment, a pair of parallel I-shaped parts 5 is formed by assembling three rectangular parallelepiped core blocks 5 a, 5 b, 5 c, and substantially U-shaped core blocks 4 are formed at both ends of these I-shaped parts 5. , 4 are connected to form a substantially oval annular core 2. Spacers 6 made of a ceramic material, which is a nonmagnetic material, are inserted in gaps set between the core blocks.

  As shown in FIG. 3, in this embodiment, the end 3 a of the coil 3 is spaced from the connection surface 4 a of the substantially U-shaped core block 4 by a distance H equal to or greater than the thickness T of the spacer 6. Is arranged.

  By adopting the above configuration, even if the leakage magnetic flux F from the edge of the I-shaped portion 5 toward the inner peripheral surface of the substantially U-shaped core book 4 is generated, the leakage magnetic flux F enters the coil 3. Disappear. Moreover, since the eddy current resulting from the said leakage magnetic flux does not generate | occur | produce in the coil 3, the loss of the reactor resulting from this does not increase. Furthermore, the effect can be further ensured by setting the distance H to be twice or more the thickness T of the spacer.

  4 to 6 show a second embodiment of the reactor according to the present invention. 4 is an external perspective view of the annular core 22, and FIG. 5 is a cross-sectional view corresponding to FIG. 2 in a state where a coil is wound around the annular core 22.

  Also in the reactor 21 according to the present embodiment, a pair of parallel I-shaped portions 25 are configured by assembling three rectangular core blocks 25a, 25b, and 25c, as in the first embodiment, and these I A substantially oval core 22 is formed by connecting substantially U-shaped core blocks 24, 24 to both ends of the character 25. Spacers 26 made of a ceramic material, which is a nonmagnetic material, are inserted in gaps set between the core blocks.

  The substantially U-shaped core block 24 has a core cross-sectional area in the direction from the U-shaped axial center of the substantially U-shaped core block toward the outer periphery, and the axial direction (see FIG. 4). On the paper surface, it is formed in a form in which the core cross-sectional area to the vertical method) is increased.

  A two-dot chain line in FIG. 5 indicates a state of the magnetic flux 30 generated in the annular core 22. As shown in this figure, a linear magnetic flux is generated in the I-shaped portion 25 around which the coil 23 is wound. On the other hand, in the said substantially U-shaped core block 24, since a core cross-sectional area becomes larger than an I-shaped part, the magnetic flux spreads that much and the magnetic flux density is falling. Thereby, the material loss in the said substantially U-shaped core block 24 part can be reduced, and it becomes possible to improve the efficiency of a reactor.

  Also, as shown in FIG. 5, in this embodiment, the core cross section of the substantially U-shaped core block 24 is increased by an amount corresponding to the thickness of the coil 23 wound around the I-shaped portion 25, The coil 23 is wound so as to fill a stepped portion corresponding to the increase in the cross-sectional area. For this reason, loss can be reduced and performance can be improved, without changing almost the whole dimension and form of the reactor 21. FIG.

  Further, in this embodiment, chamfered portions 28 and 29 are provided at the connection end portion of the substantially U-shaped core block 24. The chamfered portions 28 and 29 are formed by notching the stepped portions with the increase in the cross-sectional area of the substantially U-shaped core block in an inclined manner.

  By providing the chamfered portions 28 and 29, the distance between the edge portion of the I-shaped portion 25 and the stepped wall portion due to the increase in the cross-sectional area of the substantially U-shaped core block 24 is increased. The leakage magnetic flux between them is made difficult to occur. Moreover, since the compacting body is employ | adopted for the said substantially U-shaped core block 24, it can prevent that a corner | angular part is missing and can reduce the weight of the whole core.

  Further, as shown in FIG. 6, the end 23 a of the coil 23 is disposed at a position separated from the connection surface 24 a of the substantially U-shaped core block 24 by a distance H equal to or greater than the thickness T of the spacer 26. ing.

  Therefore, as in the first embodiment, even if a leakage flux F is generated from the inner periphery of the I-shaped portion 25 toward the inner peripheral surface of the substantially U-shaped core book 24, the leakage flux F is The coil 23 is not entered. Therefore, no eddy current is generated in the coil 23 due to the leakage magnetic flux, and the reactor loss due to this does not increase.

  In the above-described embodiment, the present invention is applied to a reactor including a powder-molded core. However, a reactor including a core formed by stacking silicon steel plates, or a reactor including a core formed from different materials. The present invention can be applied to.

  Furthermore, in the present embodiment, the connecting end portion of the substantially U-shaped core block is notched in an inclined shape and the chamfered portions 28 and 29 are provided, but the range and form of the notch are not limited.

  The present invention is not limited to the above-described embodiments. The embodiments disclosed herein are illustrative in all respects and should not be construed as being restrictive. The scope of the present invention is defined not by the above-described meaning but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  According to the present invention, loss due to leakage magnetic flux entering the coil can be prevented, and an efficient reactor can be provided.

It is a perspective view which shows the external appearance of 1st Example of the reactor which concerns on this invention. It is sectional drawing which follows the II-II line | wire of the reactor shown in FIG. It is a figure explaining the effect | action of this invention, and is an enlarged view of the principal part of FIG. It is a whole perspective view of the cyclic | annular core which concerns on a 2nd Example. It is sectional drawing equivalent to FIG. 2 of a reactor provided with the annular core shown in FIG. It is a figure explaining the effect | action of this invention, and is an enlarged view of the principal part of FIG. It is a figure which shows a prior art example, and is sectional drawing equivalent to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reactor 2 Annular core 3 Coil 4 U-shaped core block 5a Core block 5b Core block 5c Core block 5 I-shaped part 6 Spacer

Claims (6)

A pair of parallel I-shaped parts assembled with two or more core blocks, a ring-shaped core composed of a pair of substantially U-shaped core blocks connected to both ends of these I-shaped parts, A reactor comprising a coil wound around each outer circumference,
Both ends of the coil are arranged at positions where a distance greater than the thickness of the spacer inserted between the I-shaped portion and the substantially U-shaped core block is separated from the connection surface of the substantially U-shaped core block. Being a reactor.   The reactor according to claim 1, wherein the distance is at least twice the thickness of the spacer.   The reactor in any one of Claim 1 or Claim 2 which set the core cross-sectional area orthogonal to the magnetic flux direction of the said substantially U-shaped core block larger than the core cross-sectional area of the said I-shaped part.   The reactor of Claim 3 which increased the said core cross-sectional area in the direction except the inner peripheral side of the said substantially U-shaped core block.   The reactor in any one of Claim 3 or Claim 4 with which the peripheral part of the connection end surface with respect to the said I-shaped part of the said substantially U-shaped core block is missing. The reactor according to any one of claims 1 to 5, wherein at least the pair of substantially U-shaped core blocks are formed from a compacted body of magnetic powder.

Images