JP2008041877A - Reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor having improved efficiency scarecely changing the dimension and profile of a conventional reactor. <P>SOLUTION: The reactor is provided with a circular core 2 formed of a magnetic body, and a coil 3 wound around the external circumference of a predetermined part of the core. The area of the core perpendicular to the magnetic flux direction of a part other than a part having the wound coil is set larger than an area of the core of a part having the wound coil. <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 supply, and a reactor is a main component of the boost converter.

  As described in Patent Document 1, the reactor includes an annular core and a coil wound around a predetermined portion of the core. In a vehicle-mounted reactor, a pair of parallel I-shaped parts are formed by assembling two or more core blocks, respectively, due to restrictions on mounting space, manufacturing method, etc., and substantially U-shaped cores at both ends of these I-shaped parts. In many cases, a substantially oval annular core configured by connecting blocks is employed. By passing a current through the coil, an annular magnetic circuit is formed in the core.

JP2004-241475

  The loss of the annular 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.

  However, if the cross-sectional area of the core is increased, the size of the core increases, and the demand for downsizing the device cannot be met. In addition, the length of the coil wound around this also increases, and there is a risk that the resistance increases and the loss increases.

  The present invention has been devised to solve the above problems, and provides a reactor capable of reducing the loss and increasing the efficiency without substantially changing the size and form of the conventional reactor. It is.

  The invention described in claim 1 is a reactor including an annular core formed of a magnetic material and a coil wound around an outer periphery of a predetermined portion of the core, except for a portion around which the coil is wound. The core cross-sectional area perpendicular to the magnetic flux direction is set larger than the core cross-sectional area of the portion where the coil is wound.

  The present invention reduces the magnetic flux density of these portions by increasing the core cross-sectional area of the portion where the coil is not wound. Thereby, the loss as a whole reactor is reduced and the efficiency is improved. Since the core cross-sectional area of the portion where the coil is not wound is increased, the loss can be reduced and the efficiency can be improved without substantially changing the size and form of the conventional reactor.

  In particular, if the core cross-sectional area is increased by the thickness of the coil to be wound, the core cross-sectional area can be increased using dead space, thus improving the efficiency without changing the reactor configuration. Is also possible.

  The present invention can be applied to reactors having various types of annular cores. Moreover, the material which comprises the said core is not limited.

  Usually, an annular core is formed by assembling a plurality of magnetic blocks through nonmagnetic spacers. Although the said spacer is provided in order to control the performance of a reactor, a leakage magnetic flux arises from the said spacer part and loss becomes large. Since the leakage magnetic flux is generated from the end portion of each core block toward the adjacent portion, it is likely to be generated in the inner peripheral portion of the annular core. Therefore, when the core cross-sectional area is increased on the inner peripheral side, the leakage flux may increase and the loss may increase. For this reason, as in the invention described in claim 2, it is preferable to increase the core cross-sectional area in a direction other than the inner side of the annular core.

  In the invention described in claim 3 of the present application, the annular core is constituted by a pair of parallel I-shaped portions around which the coil is wound and a substantially U-shaped portion connected to both ends of the I-shaped portions. In addition, the core cross-sectional area of the substantially U-shaped part is set larger than the core cross-sectional area of the I-shaped part. The invention described in this claim is the one in which the present invention is applied to a core that is widely used in a vehicle-mounted reactor.

  In the conventional reactor, the core cross-sectional area of each part of the annular body is set to be the same, and the core cross-sectional area of the substantially U-shaped part and the cross-sectional area of the I-shaped part are the same. By increasing the core cross-sectional area of the substantially U-shaped part around which the coil is not wound, the magnetic flux density of the substantially U-shaped part can be reduced without substantially changing the dimensions and form of the reactor. It becomes.

  In the invention described in claim 4, the I-shaped portion and the substantially U-shaped portion are formed in a rectangular cross-sectional shape, and the core cross-sectional area is set large in a direction excluding the inner peripheral side of the substantially U-shaped core. Is.

  In a vehicle-mounted reactor, the core cross section is often formed in a rectangular shape, and the magnetic flux leakage tends to increase at the inner periphery. As described in the fourth aspect of the invention, by increasing the core cross-sectional area in the direction excluding the inner peripheral side, it is possible to prevent the above-described adverse effects due to the increase in the core cross-sectional area.

  Furthermore, in the core having a rectangular cross section, even when the core cross-sectional area is increased in the side surface direction of the substantially U-shaped portion, that is, in the axial direction of the annular body, at the connection end surface of the substantially U-shaped portion, The corner portion of the substantially U-shaped portion is formed to rise from the inner peripheral corner portion of the I-shaped portion. For this reason, it is possible that the leakage magnetic flux between these parts increases. In order to prevent the leakage magnetic flux, as in the invention described in claim 5, the inner peripheral corner and / or the outer peripheral corner of the connection end surface of the substantially U-shaped portion with respect to the I-shaped portion is cut off. preferable. Thereby, the distance between the inner peripheral corner portion of the I-shaped portion and the substantially U-shaped portion is increased, and it is possible to prevent magnetic flux leakage occurring therebetween. The form of the excision is not limited. For example, it can be excised so as to be chamfered or have a rounded shape.

  The present invention can be applied to a reactor including a 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.

  In particular, 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. For this reason, it is preferable to form at least the substantially U-shaped core from a magnetic material formed by compacting as in the invention described in claim 6. As a result, the core cross-sectional area can be increased in accordance with the dimensions and 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.

  By increasing the core cross-sectional area of the portion where the coil is not wound, the magnetic flux density of these portions can be reduced, and the loss of the reactor as a whole can be reduced to improve the efficiency. In addition, the loss can be reduced and the efficiency can be improved without substantially changing the dimensions and form of the conventional reactor.

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

  As shown in FIG. 1, the reactor 1 includes an annular core 2 and a coil 3 mounted around the core 2. Usually, between the core 2 and the coil 3, a bobbin for holding the coil 3 on the outer peripheral portion of the core 2 with a predetermined interval is inserted and the whole is accommodated in a box-shaped case. ing.

  FIG. 2 shows an overall perspective view of the core 2 according to the first embodiment of the present invention.

  In the present embodiment, a pair of parallel I-shaped portions 5 and 5 are formed by assembling three rectangular core blocks 5a, 5b and 5c, respectively, and substantially U-shaped at both ends of these I-shaped portions. A substantially elliptical annular core 2 is formed by connecting the core blocks 4 and 4. Spacers 6 made of a ceramic material which is a non-magnetic material are interposed between the core blocks 4, 5a, 5b and 5c.

  As shown in FIG. 2, the substantially U-shaped core block 4 includes a core cross-sectional area in a direction from the axial center of the substantially U-shaped core block toward the outer periphery, The core cross-sectional area in the direction along the direction (vertical direction on the paper surface) is increased. By increasing the core cross-sectional area, step portions 7 and 8 are formed at the connection portion between the I-shaped portion 5 and the substantially U-shaped core block 4. And as shown in FIG. 1, the said coil 3 is wound so that this step part 7 and 8 may be filled.

  FIG. 3 schematically shows the state of the magnetic flux 8 in the core 2 configured as described above. As shown in FIG. 3, a linear magnetic flux is generated in the I-shaped portion 5 around which the coil 3 is wound. On the other hand, in the portion of the substantially U-shaped core block 4, the core cross-sectional area is larger than that of the I-shaped portion, and accordingly, the magnetic flux spreads and the magnetic flux density is reduced. Thereby, the loss in the said substantially U-shaped core 4 part can be reduced, and it becomes possible to improve the efficiency of a reactor.

  As is clear from FIG. 1, in this embodiment, the core cross-sectional area of the substantially U-shaped core block 4 is increased by an amount corresponding to the thickness of the coil 3 wound around the I-shaped portion 5. The coil 3 is wound so as to fill the stepped portions 7 and 8 generated by the increase in the core cross-sectional area. For this reason, it becomes possible to improve performance, without changing the whole dimension and form of the reactor 1 almost.

  FIG. 4 shows a second embodiment of the present invention.

  In this embodiment, chamfered portions 11 and 12 are provided on the stepped portions 7 and 8 in the first embodiment shown in FIG.

  In the embodiment shown in FIG. 2, the inner peripheral corner portion 9 of the U-shaped core block 4 rises from the inner peripheral corner portion of the I-shaped portion 5 at the connection portion between the substantially U-shaped core block 4 and the I-shaped portion 5. It is formed as follows. For this reason, there is a possibility that a leakage magnetic flux from the inner peripheral portion of the I-shaped portion 5 toward the vicinity of the corner portion 9 is generated.

  In the embodiment shown in FIG. 4, the chamfered portion 11 is provided by cutting out the corner portion 9 shown in FIG. 2 into a triangular pyramid shape. By providing the chamfered portion 11, the distance between the inner peripheral edge of the I-shaped portion 5 and the inner peripheral portion of the U-shaped core block 4 is increased so that leakage magnetic flux between these portions is less likely to occur. Yes.

  Further, as apparent from the form of the magnetic flux shown in FIG. 3, the magnetic flux density is lowered by increasing the core cross-sectional area so that the magnetic flux spreads outward, but even if the core cross-sectional area suddenly increases. Magnetic flux gradually spreads. For this reason, the effect of reducing the magnetic flux density is small in the vicinity of the outer peripheral corner of the connection end face in the substantially U-shaped core. Therefore, by providing a chamfered portion 12 by cutting out this portion, the core material can be reduced without degrading the performance.

  In particular, when a powder compact is used for the U-shaped core block 4, it is possible to prevent the corners from being lost and to reduce the weight of the entire core.

  In the above-described embodiment, the present invention is applied to the reactor 1 including an annular core formed of a pair of I-shaped portions and a substantially U-shaped core block. However, the present invention is applied to a reactor including an annular core of another form. The invention can be applied.

  Further, in the embodiment, the present invention is applied to a reactor including a core formed by compacting, but the present invention is applied to a reactor including a core formed by stacking silicon steel plates or a reactor including a core formed from different materials. The invention can be applied.

  Furthermore, in 2nd Embodiment, although the internal peripheral corner | angular part and / or outer peripheral corner | angular part in the connection end surface with respect to the said I character part of the said substantially U-shaped part were excised, the range and excision form to excise are also limited. There is no. What is necessary is just to cut out in the range which reduces a leakage magnetic flux or does not affect the fall of magnetic flux density.

  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-mentioned 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.

It is a perspective view which shows the external appearance of the reactor which concerns on 1st Example of this invention. It is a perspective view which shows the external appearance of the core of the reactor shown in FIG. It is sectional drawing which shows typically the state of the magnetic flux in the reactor shown in FIG. It is a figure which shows the form of the core which concerns on 2nd Example of this invention, and is a perspective view equivalent to FIG.

Explanation of symbols

1 reactor 2 core 3 coil

Claims (6)

A reactor including an annular core formed of a magnetic body and a coil wound around the outer periphery of a predetermined portion of the core,
A reactor in which a core cross-sectional area perpendicular to a magnetic flux direction other than a portion around which the coil is wound is set larger than a core cross-sectional area of a portion around which the coil is wound.   The reactor according to claim 1, wherein the core cross-sectional area is increased in a direction other than the inside of the annular core. The annular core is composed of a pair of parallel I-shaped portions wound with the coil and substantially U-shaped portions connected to both ends of the I-shaped portions,
The reactor in any one of Claim 1 or Claim 2 which set the core cross-sectional area of the said substantially U-shaped part larger than the core cross-sectional area of the said I-shaped part.   The said I-shaped part and the said substantially U-shaped part are formed so that a core cross-sectional area may become large in the direction except the inner peripheral side of the said substantially U-shaped core while forming the said substantially U-shaped part in rectangular cross-sectional shape. Reactor.   The reactor in any one of Claim 3 or Claim 4 which cut off the inner peripheral corner | angular part and / or outer peripheral corner | angular part in the connection end surface with respect to the said I-shaped part of the said substantially U-shaped part.   The reactor in any one of Claims 1-5 in which the said substantially U-shaped part is formed from the magnetic body by which the compacting was carried out.

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