BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] A technique described in the present specification relates to a reactor including coils of an edgewise winding. Note that the reactor is a passive element using a coil, and is also referred to as an "inductor." Further, the edgewise winding indicates winding in which a flat wire is wound so that wide side surfaces (flat surfaces) of the flat wire are superimposed on one another toward a coil axis direction.

2. Description of Related Art

[0002] An electric vehicle including a hybrid vehicle includes a power converter. The power converter is a device that converts direct-current power of a battery into alternating-current power and supplies the alternating-current power to a drive motor. The power converter typically includes an inverter circuit and a voltage converter circuit. As a device used for the voltage converter circuit, a reactor including a coil of an edgewise winding is known. One example of the reactor is a technique described in Japanese Patent Application Publication No. 2010-045112 (JP 2010-045112 A). The reactor of JP 2010-045112 A includes two coils electrically connected in series to each other and arranged in parallel to each other, and an annular core passing the coils. The annular core partially projects toward both sides in an axis direction of the coils arranged in parallel to each other. Hereinafter, a projecting part thereof is referred to as a core end.

[0003] It is desirable for an in-vehicle device to be small, and the reactor is not exceptional. JP 2010-0451 12 A describes a technique to shorten a length of a core end along a coil longitudinal direction. The core end functions to lead a magnetic flux passing inside one coil to the other coil. If the length of the core end along the coil longitudinal direction is just shortened, a magnetic path through which the magnetic flux passes is narrowed. In view of this, in JP 2010-0451 12 A, the length of the core end is shortened and a projecting portion projecting along a coil end surface is provided in the core end. In the technique of JP 2010-045112 A, a magnetic path area reduced by shortening the length of the core end is supplemented by providing the projecting portion. In the technique described in JP 2010-045112 A, a lead of the coil should be drawn in a direction perpendicular to a coil axis from between the coil end surface and the core end projecting along the coil end surface. Depending on a device layout in the power converter, it may be preferable to draw the lead of the reactor in a coil axis direction. However, such a request cannot be met by the reactor of JP 2010-045112 A. That is, in the reactor of JP 2010-0451 12 A, a degree of freedom of a wiring layout of the lead is decreased by providing the projecting portion in the core end.

SUMMARY OF THE INVENTION

[0004] The present specification provides a reactor in which a projecting portion projecting in a direction perpendicular to a coil axis is provided in a core end and which has a high degree of freedom of a layout about wiring of a lead of a coil.

[0005] A reactor disclosed in the present specification comprises two coils and a core. The two coils are connected in series to each other and wound in an edgewise manner. The core is a ring core. The coils are attached to the core side by side in a radial direction of the coils. The core includes a first portion protruding from coil end surface. The first portion includes projecting portions. The projecting portions are projected along the coil end surfaces. The projecting portion includes a notch. The notch is provided at a comer of the projecting portion. A lead of the coil is placed in the notch in a coil axis direction.

[0006] The reactor described in the present specification is configured such that the projecting portions projecting in the direction perpendicular to the coil axes are provided in the core end so as to secure a magnetic path area of the core, and has a high degree of freedom of a layout about wiring of the leads of the coils. Details and further improvements of the technique described in the present specification will be described in DETAILED DESCRIPTION OF EMBODIMENTS.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a perspective view of a reactor of an embodiment;

FIG. 2A is a plan view taken along a direction of an arrow IIA in FIG. 1 ;

FIG. 2B is a side view taken along a direction of an arrow IIB in FIG. 1 ;

FIG. 3 A is a front view taken along a direction of an arrow IIIA in FIG. 1 ;

FIG. 3B is a sectional view taken along a direction of arrows IIIB in FIG. 2 A;

FIG. 4A is a sectional view taken along a direction of arrows IVA in FIG. 2A;

FIG. 4B is a sectional view taken along a direction of arrows IVB in FIG. 2A; FIG. 4C is a sectional view taken along a direction of arrows IVC in FIG. 2B;

FIG. 5 is a perspective view of a reactor of a modification;

FIG. 6 A is a front view taken along a direction of an arrow VIA in FIG. 5; and FIG. 6B is a side view taken along a direction of an arrow VIB in FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS

[0008] A reactor described in the present specification includes: two coils connected in series to each other and wound in an edgewise manner; and an annular core around which the coils are wound side by side in a radial direction. As described earlier, that part of the core which projects from a coil end is referred to as a core end. A projecting portion is provided in the core end. The projecting portion is provided on either side of the core end in a direction perpendicular to a plane including two coil axes. Further, the core end has a rectangular shape including the projecting portions in a plan view along a coil axis direction. Notches are provided at corners of the rectangular shape, so that leads of the coils pass tlirough the notches in the coil axis direction. That is, by providing the notches, it is possible to draw the leads of the coils in the coil axis direction, not in a direction perpendicular to the coil axes. In the reactor having the above structure, it is possible to secure a magnetic path in the core end by providing the projecting portions, and it is also possible to secure a degree of freedom of a lead layout.

[0009] Note that those corners of the core end at which the notches are provided are parts on which flux densities are not concentrated. That is, the comers of the core end have flux densities lower than central parts of the projecting portions. Conversely, the notches are provided in parts where the flux densities are low. On that account, if the notches are provided, they hardly affect the magnetic path and hardly cause a decrease in inductance performance.

[0010] The reactor described in the present invention includes two leads. The leads include a lead into which current flows and a lead from which the current flows out. In view of this, it is preferable that the notches be provided at two places. When viewed from the coil axis direction, the core end including the projecting portions has a rectangular shape. In part, two notches may be provided at comers on both ends of one of the projecting portions, among four comers of the rectangular shape. The two notches are convenient in a case where two leads are both placed near the same projecting portion. This makes it possible to draw the leads from the coils tlirough the notches placed near the leads, with a minimal length.

[0011] Further, the notches may be provided at two comers placed at vertically opposite angles to each other among the four corners of the rectangular shape. In a case where the leads of two coils are placed near different projecting portions, these two notches are conveniently placed near them. Accordingly, even in such a case, it is possible to draw the leads from the coils through the notches with a minimal length.

[0012] Further, a tip end surface of the projecting portion may extend so as to be placed on the same plane as radially outer peripheral surfaces of the coils. This means that a distance from the coil axes to the tip end surface of the projecting portion is equal to a distance from the coil axes to the outer peripheral surfaces of the coils. Since the projecting portion does not protrude from the coils, compactability thereof is not impaired and a wide magnetic path can be secured at the same time.

[0013] A reactor according to an embodiment is described with reference to the drawings. A reactor 10 of the present embodiment is used for a power converter provided in a hybrid vehicle or an electric vehicle. The hybrid vehicle or the electric vehicle includes an AC motor such as an induction motor or a PM motor as a drive motor. In view of this, such a vehicle is equipped with a power converter including a voltage converter circuit that boosts direct-current power of a battery, and an inverter circuit that converts the direct-current power into alternating-current power. For example, the reactor 10 is used in the voltage converter circuit. In an engine room (a motor room) in which the power converter and so on are provided, various in-vehicle devices such as the battery and the drive motor are provided. In view of this, it is also desirable for the power converter and the reactor 10 used for it to be compact. The present embodiment provides the reactor 10 having good space efficiency. Particularly, the reactor of the present specification achieves a good balance between a short length in a coil axis direction and securing of a degree of freedom of a lead layout of coils. Note that if the degree of freedom of the lead layout is high, it is possible to reduce a space where leads of the coils are wired. That is, a high degree of freedom of the lead layout contributes to compactification of the power converter.

[0014] A configuration of the reactor 10 is described with reference to FIGS. 1 to 3B. FIG. 1 is a perspective view of the reactor of the embodiment. FIG. 2A is a plan view taken along a direction of an arrow IIA in FIG. 1 , and FIG. 2B is a side view taken along a direction of an arrow IIB in FIG. 1. FIG. 3 A is a front view taken along a direction of an arrow IIIA in FIG. 1 , and FIG. 3B is a sectional view taken along a direction of arrows IIIB in FIG. 2A. Coordinate systems L, W, H represented in these figures indicate directions a length (L), a width (W), and a height (H) of the reactor 10, respectively. In the following description, an L axis direction is referred to as a "lengthwise direction L," a W axis direction is referred to as a "width direction W," and an H axis direction is referred to as a "height direction H." Note that "length", "width", and "height" are names for convenience of the description.

[0015] The reactor 10 is constituted by coils 21 , 22, a core 30, and so on. The coils 21 , 22 are winding coils formed by winding a flat wire 25 in an edgewise manner. The flat wire 25 is made of copper, for example. That is, in the coils 21 , 22, the flat wire 25 is wound so that wide side surfaces of the flat wire 25 are laminated so as to face a direction of coil axes J (the lengthwise direction L). A width (a line width) of the wide side surface of the flat wire 25 is set appropriately according to an electric property of the reactor 10 or a specification thereof. In the present embodiment, the coils 21 , 22 are wound so as to form a rectangular shape (a generally square shape) when viewed from the direction of the coil axes J. The coils 21 , 22 are made from one flat wire, and are electrically connected in series to each other. The coils 21 , 22 thus wound are put on the core 30 so as to be arranged side by side in a radial direction of a winding axis. A contour (hereinafter referred to as "coil contour") X surrounding the coils 21 , 22 thus arranged side by side forms a rectangular shape with rounded corners (see FIG. 3A).

[0016] As described above, the coils 21 , 22 are made from one flat wire 25. Accordingly, one end of the flat wire 25 corresponds to a leading portion 25a of the coil 21 , and the other end of the flat wire 25 corresponds to a leading portion 25b of the coil 22. Further, both coils are connected to each other by that intermediate part 25c of the flat wire 25 which is connected to an end edge (or a start edge) of the coil 21 and a start edge (or an end edge) of the coil 22. In the reactor 10, drawing positions of the leading portions 25a, 25b of the coils 21 , 22 are set in one long side of the coil contour X. Note that, in FIGS. 2A, 2B, and 3 A, some of lines appearing by laminating the coils 21 , 22 are omitted. Further, the coil contour X indicated by an alternate long and short dash line in FIG. 3A is illustrated slightly larger than a contour surrounding the coils 21 , 22, so as to avoid overlap and mixture with a continuous line indicating an outer circumference of the coils 21 , 22.

[0017] The core 30 is a magnetic material member for increasing inductances of the coils 21 , 22, and is constituted by core winding portions 31 , a core end 35, and a core end 36. The annular core 30 is constituted by combining two core winding portions 3 1 and the core ends 35, 36. Due to the annular core 30, a magnetic path (a magnetic circuit) forms a square ring in a radial plan view (hereinafter just referred to as "a plan view of the reactor 10") in which two coils 21 , 22 are arranged side by side (see FIG. 2 A). These core members are made of a magnetic material such as iron or steel, and configured such that a composite soft magnetic material is molded in a compressive manner or electromagnetic steel sheets are laminated, for example. In the present embodiment, the coils 21 , 22 are wound so as to form a rectangular shape when viewed from the direction of the coil axes J. On that account, the core winding portions 31 are formed in a rectangular column shape. Similarly, those parts of the core ends 35, 36 which are connected to the core winding portions 31 are also formed in a rectangular column shape. Note that a bobbin is placed around the core winding portion 31 , and the coil is wound around the bobbin. However, the bobbin is not illustrated herein.

[0018] In the direction of the coil axes J, the core end 35 is opposed to one end surfaces of the core winding portions 31 , and the core end 36 is opposed to the other end surfaces of the core winding portions 31. The core ends 35, 36 correspond to those parts of the core 30 which project from the ends of the coils 21 , 22. In the present embodiment, while the reactor 10 is shortened in the lengthwise direction L, lengths of the core ends 35, 36 in the height direction H are longer than the core winding portions 31 so as to secure a magnetic path area equivalent to a case where the reactor 10 is large in the lengthwise direction L. That is, as illustrated in FIG. 3B, the core end 35 has projecting portions 35a, 35b projecting along end surfaces of the coils 21 , 22. In FIG. 3A, the projecting portions are not illustrated. That is, the core end 35 includes the projecting portions 35a, 35b projecting along the coil end surfaces in a direction perpendicular to a plane including two coil axes J. Note that "the direction perpendicular to a plane including two coil axes J" corresponds to a direction along the coordinate axis H.

[0019] The projecting portions 35a, 35b are configured such that tip end surfaces thereof extend to a position at which the tip end surfaces are placed on the same plane as radially outer peripheral surfaces 21 a, 22a of the coils 21 , 22. The tip end surfaces indicate radially outer surfaces of the projecting portions 35a, 35b. In other words, the tip end surfaces of the projecting portions 35a, 35b are flush with the outer peripheral surfaces 21 a, 22a. The outer peripheral surface 22a is indicated by a bold continuous line B in FIG. 3B. Note that the outer peripheral surface 21 a of the coil 21 is placed on a near side relative to the bold continuous line B on a plane of paper in FIG. 3B. Similarly, the core end 36 includes projecting portions 36a, 36b projecting along coil end surfaces in the direction perpendicular to the plane including two coil axes J. The projecting portions 36a, 36b are configured such that tip end surfaces thereof extend to positions at which the tip end surfaces are placed on the same plane as the radially outer peripheral surfaces 21 a, 22a of the coils 21 , 22.

[0020] Further, in other words, the core end 35 includes paired projecting portions 35a, 35b in both ends thereof in the direction perpendicular to the plane including two coil axes J. Similarly, the core end 36 includes paired projecting portions 36a, 36b in both ends thereof in the direction perpendicular to the plane including two coil axes J. The core ends 35, 36 have a T shape as well illustrated in FIG. 3B.

[0021] As such, in the core 30, the core end 35 including the projecting portions 35a, 35b is provided in one ends of the coils 21 , 22 along the coil axes J, and the core end 36 including the projecting portions 36a, 36b is provided in the other ends of the coils 21 , 22. The projecting portions 35a, 35b, 36a, 36b achieve a reduction in the reactor 10 in the lengthwise direction L without reducing a sectional area of a magnetic path outside the coil ends. The reason is as follows: in FIG. 3B, a reduction in the area of the core due to a reduction in the length of the core 30 in the lengthwise direction L is compensated by an increase in the area of the core by lengthening the lengths of the core ends 35, 36 in the height direction H. That is, the projecting portions 35a, 35b, 36a, 36b achieve the compactification of the reactor 10. Note that, in terms of the securing of the area of the core and space efficiency, it is most preferable to extend the projecting portions 35a, 35b to the positions where the tip end surfaces of the projecting portions 35a, 35b are flush with the coil outer peripheral surfaces 21 a, 22a.

[0022] On the other hand, the projecting portions 35a, 35b, 36a, 36b cover the end surfaces of the coils 21 , 22 in the direction of the coil axes J. Accordingly, it is difficult to draw the leading portion 25a, 25b (both ends of the flat wire 25) from the coils 21 , 22 in the direction of the coil axes J. In view of this, in the present embodiment, notches 37, 38 are provided at comers of the core end 35. The leading portions 25a, 25b of the coils 21 , 22 can extend in the direction of the coil axes J through the notches 37, 38.

[0023] That is, the notches 37, 38 are provided at those comers among four comers of the core end 35 which are closest to parts (drawing positions) from which the leading portions 25a, 25b are desired to be drawn from the coils 21 , 22. In the reactor 10 of the present embodiment, the drawing positions of the leading portions 25a, 25b of the coils 21 , 22 are set in both ends of one long side of the coil contour X. On that account, the notches 37, 38 are provided on both sides of the projecting portion 35a that is close to the one long side of the coil contour X. More specifically, the notch 37 is formed in the core end 35 for the leading portion 25a of the coil 21 , and the notch 38 is formed in the core end 35 for the leading portion 25b of the coil 22.

[0024] As described earlier, the coils 21 , 22 are wound in an edgewise manner. That is, the wide side surfaces of the flat wire 25 face the direction (the lengthwise direction L) of the coil axes J. In view of this, in the present embodiment, the leading portions 25a, 25b are drawn from the end surfaces of the coils 21 , 22 such that the leading portions 25a, 25b are bent generally at right angles so as to be directed toward the direction of the coil axes J, as illustrated in FIG. 2 A. Accordingly, the notches 37, 38 are each formed in a rectangular shape, as a sufficient shape, constituted by a side (a side in the width direction W) having a length longer than an allowable range of the drawing position of the leading portion 25a, 25b, and a side (a side in the height direction H) having a length longer than a width of the wide surface of the flat wire 25. This is just an example, and the shape and size of the notches 37, 38 are set appropriately to a round shape, a polygonal shape, or the like shape other than the rectangular shape according to other factors such as a mechanical configuration, an electric specification, or the like. Note that the drawing positions of the leading portions 25a, 25b are set appropriately according to a layout inside the power converter using the reactor 10, and an electric property or a specification of the reactor 10.

[0025] Such notches 37, 38 are formed in the core end 35 constituting the core 30. In view of this, it is desirable that the influence that the notches 37, 38 give to a magnetic flux passing through the core 30 be small. That is, cutting that part of the core end 35 which has a high flux density causes a reduction in inductance performance. Accordingly, it is preferable that the notches 37, 38 be provided in those parts of the core end 35 which have a low flux density. Here, the density distribution (simulation) of magnetic fluxes passing through the core end 35 and the other core end 36 is described below with reference to FIGS. 4A to 4C. FIGS. 4A to 4C are explanatory views each showing a distribution property of a flux density when viewed in a direction of predetermined arrows in FIG. 2. FIGS. 4A to 4C show results of the simulation of the flux density. FIG. 4A illustrates a partial section taken along a direction of arrows IVA in FIG. 2A, FIG. 4B illustrates a partial section taken along a direction of arrows IVB in FIG. 2A, and FIG. 4C illustrates a partial section taken along a direction of arrows IVC in FIG. 2B. In these figures, the level of the flux density is expressed by density of pitches of hatching: a part with a high flux density is indicated by hatching with narrow pitches; and a part with a low flux density is indicated by hatching with wide pitches.

[0026] First, as an example of a flux density distribution of the core end 35, a flux density distribution around that corner on one end side of the projecting portion 35a at which the notch 37 is formed (in a partial section taken along the direction of the arrows IVA in FIG. 2A) is examined. As illustrated in FIG. 4A, it is found that the flux density distribution in this section is such that the flux density tends to be higher in a part closer to the coil 21 , and the flux density tends to be lower in a part farther from the coil 21. It is found that the flux density is the lowest in that comer vicinal area 101 (within an ellipse indicated by a broken line in FIG. 4A) of the projecting portion 35a at which the notch 37 is formed, as compared with the other parts. In the meantime, in a flux density distribution in an intermediate part of the projecting portion 35a as illustrated in FIG. 4B (in a partial section taken along the direction of the arrows IVB in FIG. 2A), it is found that the flux density is not low in a part 102 close to a center of the projecting portion 35a (within an ellipse indicated by a broken line in FIG. 4B). That is, it is found that the flux density is higher in the part 102 close to the center than in the corner vicinal area 101 of the projecting portion 35a illustrated in FIG. 4A. That is, in the projecting portion 35a of the core end 35, it is found that the flux density is lower at those comers on both ends at which the notches 37, 38 are provided than in the other parts including the part close to the center.

[0027] An example of the flux density distribution shown in FIG. 4C is a flux density distribution in an edge vicinal area 103 (within an ellipse indicated by a broken line in FIG. 4C) of that side part of the core end 36 in which the projecting portions 36a, 36b are not formed, that is, that side part of the core end 36 which constitutes the height direction H thereof (a partial section taken along the direction of the arrows IVC in FIG. 2B). As can be seen from the figure, it is found that the flux density in the edge vicinal area of that side part of the core end 35 or the other core end 36 which constitutes the height direction H thereof is generally as low as the comer vicinal area 101 of the projecting portion 35a as examined in FIG. 4A. Thus, the flux densities in those comers on both ends of the core end 35 at which the notches 37, 38 are provided are lower than the other parts of the core end 35 or as low as the part with the lowest flux density. Even if the notches 37, 38 are formed at the comers on both ends of the core end 35, that hardly affects a magnetic path constituting a magnetic circuit of the core 30 and hardly causes a decrease in inductance performance.

[0028] Note that the core 30 is provided with a gap. More specifically, gaps 32 are provided between the core winding portions 31 and the core end 35 and between the core winding portions 31 and the core end 36 (see FIG. 3B). The gaps 32 are formed by use of a gap material made of a nonmagnetic material such as alumina, for example. Further, although not illustrated herein, a bobbin is provided between the core 30 and each of the coils 21 , 22. The bobbin secures electric insulation between the core 30 and each of the coils 21 , 22 and facilitates positioning of the coils 21 , 22 to be put on the core 30. The bobbin is made of a material having a high insulation resistance and a high heat resistance.

[0029] In the reactor 10 of the present embodiment, the notches 37, 38 through which the leading portions 25a, 25b of the coils 21 , 22 pass in the direction of the coil axes J, are formed at the comers of the core end 35. Hereby, the leading portions 25a, 25b can be drawn in the direction of the coil axes J without drawing the leading portions 25a, 25b in the direction perpendicular to the coil axes J. Hence, it is not necessary to provide a space for wiring of the leading portions 25a, 25b in the direction perpendicular to the coil axes J. Accordingly, even if the projecting portions 35a, 35b projecting in the direction perpendicular to the coil axes J are provided in the core end 35, it is possible to provide the reactor 10 having good space efficiency in terms of the wiring of the leading portions 25a, 25b of the coils 21 , 22.

[0030] Further, in the reactor 10 of the present embodiment, the notches 37, 38 are provided at the comers on both ends of one projecting portion 35a among four comers of the rectangular shape of the core end 35. Accordingly, the reactor 10 is favorably applicable to a case where the drawing positions of the leading portions 25a, 25b of the coils 21 , 22 are set in both ends of one long side of the coil contour X. This makes it possible to draw the leading portions 25a, 25b from the coils 21 , 22 with a minimal length through the notches 37, 38 placed near the leading portions 25a, 25b.

[0031] Next will be described a reactor in which a notch is formed in the other projecting portion, as a modification of the reactor 10 in which the notches 37, 38 are formed in one projecting portion 35a of the core end 35. FIG. 5 is a perspective view of a reactor 50 of the modification. Further, FIG. 6A is a front view taken along a direction of an arrow VIA in FIG. 5, and FIG. 6B is a side view taken along a direction of an arrow VIB in FIG. 5.

[0032] The reactor 50 of the modification is also constituted by coils 71 , 72, a core 60, and so on, similarly to the reactor 10. The coils 71 , 72 are different from the coils 21 , 22 of the reactor 10 in the drawing positions of the leading portions 25a, 25b. That is, in the coils 21 , 22, the drawing positions of the leading portions 25a, 25b are set in both ends of one long side of the coil contour X. However, in the coils 71 , 72, drawing positions of leading portions 25a, 25b are set in one end of one long side of a coil contour X and in the other end of the other long side of the coil contour X. That is, the drawing positions of the leading portions 25a, 25b are set near two comers placed at vertically opposite angles in the coil contour X.

[0033] The core 60 is configured generally in a similar manner to the core 30 of the reactor 10. That is, in a radial plan view in which two coils 71 , 72 are arranged side by side, two core winding portions 61 , a core end 65, and a core end 66 are combined to form the annular core 60 so that a magnetic circuit forms a square shape. Further, in a radial side view in which two coils 71 , 72 overlap with each other (see FIG. 6B), the core end 65 projects in one end direction and the core end 66 projects in the other end direction, respectively, relative to the core winding portions 61. Further, in the core end 65, projecting portions 65a, 65b projecting toward both side in a direction perpendicular to coil axes J are formed so as to be flush with outer peripheral surfaces 71 a, 72a of the coils 71 , 72. Also, in the core end 66, projecting portions 66a, 66b projecting toward both side in the direction perpendicular to the coil axes J are formed so as to be flush with the outer peripheral surfaces 71 a, 72a of the coils 71 , 72. Note that core members such as the core winding portions 61 , the core end 65, the core end 66, and the like are made of a magnetic material such as iron or steel, similarly to the core members of the core 30.

[0034] In the reactor 50 of the modification, notches 67, 68 are provided so as to correspond to the drawing positions of the leading portions 25a, 25b of the coils 71 , 72. The drawing position of the leading portion 25a of the coil 71 is the same as that of the leading portion 25a of the coil 21 of the reactor 10. On that account, its corresponding notch 67 is formed in the projecting portion 65a of the core end 65, similarly to the notch 37 formed in the projecting portion 35a of the core end 35. The shape and the like of the notch 67 are the same as the notch 37. In the meantime, the drawing position of the leading portion 25b of the coil 72 is different from the leading portion 25b of the coil 22 of the reactor 10. Accordingly, a position of the notch 68 to be provided in the core end 65 is different from a formation position of the notch 38 of the reactor 10. That is, among four comers of the core end 65, the notch 67 is placed at one of the comers placed at vertically opposite angles, that is, in one end of the projecting portion 65a, and the notch 68 is placed at the other one of the comers placed at vertically opposite angles, that is, in the other end of the projecting portion 65b. The shape and the like of the notch 68 are the same as the notch 38 except that the notch 68 is reversed to the notch 38 in the height direction H.

[0035] The notches 67, 68 formed in the core end 65 are also provided at the comers of the core end 65. Accordingly, flux densities in the notches 67, 68 are lower than those in the other parts of the core end 65, or generally as low as a part of the core end 65 with a lowest flux density, as examined with reference to FIGS. 4A to 4C. Accordingly, even if the notches 67, 68 are formed at two comers placed at vertically opposite angles in the core end 65, that hardly affects a magnetic path constituting a magnetic circuit of the core 60 and hardly causes a decrease in inductance performance.

[0036] In the reactor 50 of the modification, the notches 67, 68 are provided at two comers placed at vertically opposite angles, from among four comers of the rectangular shape of the core end 65. Accordingly, this configuration is favorably applied to a case where the drawing positions of the leading portions 25a, 25b are set in one end of one long side of the coil contour X and in the other end of the other long side of the coil contour X. This makes it possible to draw the leading portions 25a, 25b from the coils 71 , 72 with a minimal length through the notches 67, 68 placed near the leading portions 25a, 25b.

[0037] As described above, the reactor 10 of the present embodiment includes: two coils 21 , 22 (71 , 72) connected in series to each other and wound in an edgewise manner; and an annular core 30 (60) around which the coils 21 , 22 (71 , 72) are wound side by side in a radial direction. Further, in a radial side view in which two coils 21 , 22 (71 , 72) overlap with each other, the core end 35 (65) projecting from an end of the coils 21 , 22 (71 , 72) in the direction of the coil axes J includes paired projecting portions 35a, 35b (65a, 65b) projecting toward both sides in the direction perpendicular to the coil axes J so as to be placed on the same plane as the radially outer peripheral surfaces 21 a, 22a (71 a, 72a) of the coils 21 , 22 (71 , 72). Note that that "the core end includes projecting portions in a radial side view in which two coils overlap with each other" indicates that "the core end includes projecting portions extending along coil end surfaces in a direction perpendicular to a plane including two coil axes J."

[0038] Further, in a plan view in the direction of the coil axes J, the core end 35 (65) has a rectangular shape including the paired projecting portions 35a, 35b (65a, 65b), and the notches 37, 38 (67, 68) through which the leading portions 25a, 25b of the coils 21 , 22 (71 , 72) pass in the direction of the coil axes J are provided at the corners of the rectangular shape. Since the notches 37, 38 (67, 68) are provided in the projecting portion 35a (65a, 65b), the leading portions 25a, 25b can be drawn in the direction of the coil axes J through the notches 37, 38 (67, 68) without drawing the leading portions 25a, 25b in the direction perpendicular to the coil axes J. Hence, it is not necessary to provide a space for wiring of the leading portions 25a, 25b in the direction perpendicular to the coil axes J. Accordingly, even if the projecting portions 35a, 35b (65a, 65b) projecting in the direction perpendicular to the coil axes J are provided in the core end 35 (65), it is still possible to provide the reactor 10 (50) having good space efficiency in terms of the wiring of the leading portions 25a, 25b of the coils 21 , 22 (71 , 72).

[0039] Below are notes regarding the technique explained in the embodiments. The height axis H in the figures corresponds to one example of "a direction perpendicular to a plane including two coil axes." The outer peripheral surfaces 21 a, 22a, 71 a, 71b correspond to examples of "radially outer peripheral surfaces of coils." The projecting portions 35a, 35b or the projecting portions 65a, 65b correspond to one example of "paired projecting portions." The leading portions 25a, 25b correspond to one example of "leads of the coils." The projecting portions 35a, 65a correspond to examples of "one projecting portion." The coil axes J correspond to one example of "coil axes."

[0040] The specific example of the invention has been explained in detail.

However, the example is for illustration only, and does not limit the scope of the claims. The technique described in the scope of the claims includes the foregoing example with various modifications and changes. Technical elements described in the present specification or the drawings exhibit a teclmical usability solely or in various combinations, and are not limited to combinations as described in the claims as of filing the present application. Further, the technique exemplified in the present specification or the drawings can achieve a plurality of objects at the same time, and has a teclmical usability by achieving one of those objects.