WO2018235648A1

WO2018235648A1 - Coil antenna

Info

Publication number: WO2018235648A1
Application number: PCT/JP2018/022191
Authority: WO
Inventors: 隆洋佐藤; 裕二新井
Original assignee: 株式会社村田製作所
Priority date: 2017-06-19
Filing date: 2018-06-11
Publication date: 2018-12-27
Also published as: JP2020161852A

Abstract

The purpose of the present invention is to provide a coil antenna in which a magnetic core to which a body part is provided is mounted and joined to a top surface of a thin plate-shaped base member made of resin, wherein a wire material of a coil of a winding shaft that is orthogonal to the top surface of the base member does not penetrate into a gap between the magnetic core and the base member even if warping occurs in the base member. A coil antenna 1 comprises: a magnetic core 20 having a body part 21; a base member 30 that has a mounting surface on which the magnetic core 20 is mounted, one end of the body part 21 in the thickness direction being disposed on the mounting surface; and a first coil 11a that is wound around the outer periphery of the body part 21 and that is mounted on the mounting surface in plan view from the thickness direction. The base member 30 includes protrusions 50 that are provided on the mounting surface and disposed between the magnetic core 20 and the first coil 11a, and that protrude towards the other end of the body part 21 in the thickness direction.

Description

Coil antenna

The present invention relates to a coil antenna.

BACKGROUND ART Conventionally, a small three-axis coil antenna is used in a keyless entry system that wirelessly operates locking and unlocking of a door of a vehicle or a receiver of a security device.

For example, in Patent Document 1, a half-sided magnetic core provided with a ridge in the body portion is mounted on the upper surface of a thin plate-shaped base member made of resin and combined, and three coils are wound around the single-sided magnetic core and the base member A rotated three-axis coil antenna is disclosed. Each of the three coils has a different winding axis direction, and is connected to a terminal provided on the base member.

JP, 2015-220512, A

However, in the three-axis coil antenna of Patent Document 1, when the base member is warped, a gap is generated between the end portion of the body of the half core and the base member. Since this gap is generated in a direction parallel to the upper surface of the base member, among the three coils, the wire of the coil whose winding axis direction is orthogonal to the upper surface of the base member tends to enter this gap. As a result, the wire rod of the coil is pinched between the one-sided magnetic core and the base member, and may be disconnected due to the vibration and the change of the outside air.

An object of the present invention is a coil antenna combining a magnetic core including a body portion and a thin plate-like base member made of resin, wherein the coil antenna is wound around the body portion of the core even when the base member is warped. The wire rod of the present invention is to provide a coil antenna which does not get into the gap between the magnetic core and the base member.

According to a first aspect of the present invention, there is provided a base having a magnetic core having a body portion, and a mounting surface on which the magnetic core is to be mounted, one end of the body portion in the thickness direction being disposed on the mounting surface. A coil antenna comprising: a first coil wound around an outer periphery of the trunk and disposed on the mounting surface when viewed in plan from the thickness direction, wherein the base member is A projection is provided on the mounting surface and is disposed between the magnetic core and the first coil, and is provided with a protrusion that protrudes in the direction of the other end of the body in the thickness direction.

According to the present invention, since the protrusion is formed between the magnetic core and the coil, the wire of the coil is prevented from invading between the magnetic core and the base member even when the base member is along, and the disconnection defect is prevented. It can be prevented.

It is a perspective view showing the appearance of the coil antenna concerning a 1st embodiment of the present invention. It is a perspective view which shows the external appearance of a magnetic core. It is a top view of a magnetic core. It is a figure for demonstrating the groove shape of a magnetic core and a trunk | drum in the top view of FIG. It is the side view which looked at the magnetic core from the Y direction. It is a side view looking at the magnetic core from the X direction, It is a bottom view of a magnetic core. It is a figure for demonstrating the shape of the recessed part formed in the magnetic core. It is a figure for demonstrating the position in which the recessed part is formed. It is a perspective view which shows the external appearance of a base member. It is a perspective view which shows the external appearance of a metal frame. It is a top view of a base member. It is the side view which looked at the base member from the Y direction. It is the side view which looked at the base member from the X direction. It is a bottom view of a base member. It is a top view which expands and shows the boundary position of the upper surface of a mounting part, and a ridge part. It is a perspective view which expands and shows the boundary position of the upper surface of a mounting part, and a ridge part. It is a side view which shows the state which combined the magnetic core and the base member. It is a perspective view which shows the state which combined the magnetic core and the base member. It is a top view which shows the state which combined the magnetic core and the base member. It is a bottom view which shows the state which combined the magnetic core and the base member. It is a figure explaining the case where curvature arises in a base member. It is an enlarged view of the fitting part periphery of a protrusion and a recessed part. It is a perspective view which shows the external appearance of the base member A in 2nd Embodiment of this invention. It is a perspective view which shows the state which combined the magnetic core and base member in 2nd Embodiment. It is a perspective view which shows the state which combined the magnetic core and base member in 2nd Embodiment.

Various embodiments for carrying out the present invention will be described hereinafter with reference to the drawings. In the drawings, corresponding members having the same function are denoted by the same reference numerals. Although the embodiments are shown separately for convenience in consideration of the description of the main points or the ease of understanding, partial replacement or combination of the configurations shown in the different embodiments is possible. In the second and subsequent embodiments, descriptions of matters in common with the first embodiment will be omitted, and only different points will be described. In particular, the same operation and effect by the same configuration will not be sequentially referred to in each embodiment.

First Embodiment
A three-axis coil antenna according to a first embodiment of the present invention will be described with reference to the attached drawings. FIG. 1 is a perspective view showing an appearance of a three-axis coil antenna according to a first embodiment of the present invention.

As shown in FIG. 1, the three-axis coil antenna 1 of the present embodiment includes a first coil 11 a, a second coil 11 b, and a third coil 11 c, a magnetic core 20, and a base member 30. Then, the first coil 11a, the second coil 11b, and the third coil 11c are wound around the magnetic core 20 and the base member 30 such that their winding axes are orthogonal to each other. The base member 30 is provided with a plurality of external connection terminals 31 and a plurality of binding terminals 32.

2 is a perspective view showing the appearance of the magnetic core 20, FIG. 3 is a plan view of the magnetic core 20, and FIG. 4 is for explaining the groove shape of the magnetic core 20 and the body 21 in the plan view of FIG. FIG. FIG. 5 is a side view of the magnetic core 20 as viewed from the Y direction, FIG. 6 is a side view of the magnetic core 20 as viewed from the X direction, and FIG. 7 is a bottom view of the magnetic core 20. FIG. 8 is a view for explaining the shape of the recess formed in the magnetic core 20. As shown in FIG.

The magnetic core 20 is formed of a ferrite core, and as shown in FIGS. 2 to 8, the body portion 21 and a ridge portion 22 provided at an end portion on the thickness direction (Z direction) side of the body portion 21 Is equipped.

The body portion 21 has a shape in which concave portions are provided in a plurality of octagonal prisms, and the collar portion 22 has a shape in which concave portions are provided in a plurality of octagonal plate-like portions. As shown by dotted lines in FIG. 4, when the cross-sectional shape of the body 21 in the direction perpendicular to the Z direction is considered to be octagonal, the outer peripheral edge 22 a of the flange 22 is a virtual core of the magnetic core 20. When viewed from the center of gravity C, it has a size located outside the outer peripheral edge of the octagon in the cross section of the body 21.

As shown in FIG. 4, the ridge portion 22 has a shape in which a rectangular body portion A1 and a rectangular body portion A2 are removed from an octagonal plate-like portion. Further, as shown in FIG. 4, the collar portion 22 and the body portion 21 have a shape in which the rectangular body portion A2 and the rectangular body portion A3 are removed from the octagonal plate-like portion and the octagonal prism. .

The rectangular portion A1 has a depth D1 toward the center of gravity C in the Y direction from the outer peripheral edge 22a of the ridge 22 in the X direction, a width W1 in the X direction, and a thickness T1 in the Z direction as shown in FIG. Rectangular body part. The rectangular portion A2 is a rectangular portion having a depth D2 toward the center of gravity C in the X direction from the outer peripheral edge 22a of the ridge 22 in the Y direction, a width W1 in the X direction, and a thickness T1 in the Z direction. . In the present embodiment, the width W1 of the rectangular body portion A1 and the width W2 of the rectangular body portion A2 are set to be equal. Further, the depth D1 of the rectangular body portion A1 and the depth D2 of the rectangular body portion A2 are set to be equal. Furthermore, a virtual straight line in the Y direction passing through the center of gravity C of the magnetic core 20 passes the center in the X direction of width W1, and a virtual straight line in the X direction passing through the center of gravity C passes the center in the Y direction of width W2. Is set as.

The rectangular portion A3 is a rectangular portion having a depth D3 further from the rectangular portion A1 toward the center of gravity C in the Y direction, a width W in the X direction W1, and a thickness T in the Z direction T2 as shown in FIG. is there. The rectangular body portion A4 is a rectangular body portion having a depth D4 going further toward the center of gravity C in the X direction from the rectangular body portion A2, a width W2 in the X direction, and a thickness T2 in the Z direction.

The rectangular portions A1, A2, A3 and A4 are not removed by processing such as scraping the magnetic core 20, but the rectangular portions A1, A2, A3 and A4 are removed when the magnetic core 20 is molded A mold etc. is used so that it may become a shape. As a result, as shown in FIG. 3, the magnetic core 20 has a shape in which a recess 23 having a width W1 and a depth D5 and a recess 24 having a width W2 and a depth D6 are provided.

Furthermore, in the body portion 21, a rectangular portion A5 indicated by a two-dot chain line in which the X direction is a longitudinal direction in FIG. 4 and a rectangular portion A6 indicated by a dashed line in a Y direction are a octagonal prism. Has a shape removed from the upper surface portion of the

The rectangular portion A5 is a rectangular portion whose central position in plan view in FIG. 4 coincides with the center of gravity C. The length in the longitudinal direction in the X direction is L1, the width in the Y direction is W2, and FIGS. As shown in the drawing, the thickness in the Z direction from the upper surface of the body portion 21 is a rectangular portion with T3. The rectangular portion A6 is a rectangular portion whose central position in plan view in FIG. 4 coincides with the center of gravity C, the length in the longitudinal direction in the Y direction is L2, the width in the X direction is W1, and As shown in FIG. 5, the thickness in the Z direction from the upper surface of the trunk portion 21 is a rectangular portion of T4.

The rectangular portions A5 and A6 are not removed by processing such as scraping the magnetic core 20, but when molding the magnetic core 20, a mold or the like is formed so that the rectangular portions A5 and A6 are removed. Is used. As a result, as shown in FIG. 2, FIG. 5, and FIG. 6, the body portion 21 of the magnetic core 20 has a shape in which the recessed

portions

21a and 21b are provided.

In the present embodiment, as described later, the magnetic core 20 and the base member 30 (see FIG. 10) are combined, the first coil 11a is wound around the recess 21b and the base member 30, and around the recess 21a and the base member 30. The second coil 11b is wound.

As can be clearly understood from FIGS. 7 and 8, a plurality of recessed portions 21 d are provided on the side surface portion of the trunk portion 21 located below the collar portion 22 (in the Z direction). The concave portion 21 d has a rounded shape corresponding to a part of the side surface of the cylinder, and extends in the Z direction from the top surface of the trunk portion 21 to the bottom surface. That is, the plurality of recessed portions 21 d are provided on the side surface of the trunk portion 21.

FIG. 9 is a diagram for explaining the position where the recess 21 d is formed. As shown in FIG. 9, when the cross-sectional shape in the direction perpendicular to the Z direction of the trunk 21 before the

recesses

23 and 24 and the recess 21 d are provided is considered to be an octagon, the recess 21 d is an octagonal corner portion That is, it has a shape obtained by indenting the side ridge 21e when the trunk portion 21 is considered to be an octagonal prism. When the base member 30 and the magnetic core 20 are combined with each other, the projections described later fit into these recesses 21 d. Details will be described later.

Next, the base member 30 in the present embodiment will be described with reference to the attached drawings. FIG. 10 is a perspective view showing the appearance of the base member 30, and FIG. 11 is a perspective view showing the appearance of the metal frame. 12 is a plan view of the base member 30, FIG. 13 is a side view of the base member 30 as viewed in the Y direction, and FIG. 14 is a side view of the base member 30 as viewed in the X direction. FIG. 15 is a bottom view of the base member 30. FIG.

The base member 30 includes a resin portion 35 made of heat-resistant resin including the placement portion 33 and the collar portion 34, a plurality of external connection terminals 31 held by the resin portion 35, and a plurality of pieces held by the resin portion 35. A binding terminal 32 is provided.

The resin portion 35 is preferably integrally molded of a resin having insulating properties, heat resistance and moldability, and specifically, is preferably molded of a resin such as polyphenylene sulfide, liquid crystal polymer, polyethylene terephthalate, polybutylene terephthalate or the like. The molding method can be used for those shaping | molding.

Similar to the magnetic core 20, the resin portion 35 has a shape in which a plurality of recessed

portions

36 and 37 are provided in an octagonal plate member. The Y-direction interval of the outer peripheral edge 34a in the X direction in the resin portion 35 shown in FIG. 12 and the Y-direction interval of the outer peripheral edge 22a in the X direction in the magnetic core 20 shown in FIG. Further, the X-direction interval of the Y-direction outer peripheral edge 34a in the resin portion 35 shown in FIG. 12 and the X-direction interval of the Y-direction outer peripheral edge 22a in the magnetic core 20 shown in FIG.

The size and position of the

recesses

36 and 37 of the resin portion 35 correspond to the

recesses

23 and 24 of the magnetic core 20. The width in the X direction of the recess 36 of the resin portion 35 is equal to the width in the X direction of the recess 23 in the magnetic core 20 and is W1. The width in the Y direction of the recess 37 in the resin portion 35 is Y of the recess 24 in the core 20 Equal to the width of the direction, W2. The depth in the Y direction of the recess 36 in the resin portion 35 is equal to the depth in the Y direction of the recess 23 in the magnetic core 20 and is D5. The depth in the X direction of the recess 37 in the resin portion 35 is the recess 24 in the magnetic core 20 Equal to the depth in the X direction of the image, and is D6.

In the

recesses

36 and 37 of the resin portion 35, the position in plan view shown in FIG. 12 corresponds to the position in plan view of the

recesses

23 and 24 in the magnetic core 20 shown in FIG. That is, the center position of the recess 36 in the resin portion 35 in the X and Y directions coincides with the center position of the recess 23 in the magnetic core 20 in the X and Y directions, and the center position of the recess 37 in the resin portion 35 in the X and Y directions The center position coincides with the center position of the recess 24 of the magnetic core 20 in the X and Y directions.

FIG. 11 is a perspective view showing the appearance of the first metal frame 40 and the second metal frame 41. As shown in FIG. In the resin portion 35, the first metal frame 40 and the second metal frame 41 that constitute the external connection terminal 31 and the binding terminal 32 are inserted. The connecting portion 40 a of the first metal frame 40 does not make an electrical connection, and has a function of enhancing the rigidity of the resin portion 35 in a state of being inserted into the resin portion 35.

The upper surface (mounting surface) of the mounting portion 33 in the resin portion 35 is formed substantially flat, and as shown in FIG. 12, the octagonal shape of the

concave portions

36 and 37 in a plan view seen from the Z direction It has a shape with a part. The size of the upper surface of the mounting portion 33 is substantially the same as the size of the bottom surface of the magnetic core 20, and the magnetic core 20 and the base are adhered by bonding the upper surface of the mounting portion 33 and the bottom surface of the magnetic core 20 using an adhesive. The member 30 can be combined.

As shown in FIGS. 14 and 15, the bottom of the mounting portion 33 of the resin portion 35 has a length L1 in the longitudinal direction in the X direction, a width W2 in the Y direction, and a depth T5 in the Z direction. A recess 33a is provided. Further, on the bottom surface of the mounting portion 33, as shown in FIGS. 13 and 15, a recess 33b having a length L2 in the longitudinal direction in the Y direction, a width W1 in the X direction, and a depth T in the Z direction Is provided.

The recesses 33 a and the recesses 33 b of the mounting portion 33 correspond to the

recesses

21 a and 21 b (see FIGS. 5 and 6) of the magnetic core 20, and the recesses of the magnetic core 20 in the state where the magnetic core 20 and the base member 30 are combined. The first coil 11 a is wound around the portion 21 b and the recess 33 b of the placement unit 33. Further, the second coil 11 b is wound around the recess 21 a of the magnetic core 20 and the recess 33 a of the mounting portion 33.

The flange portion 34 of the resin portion 35 is similar in shape and size to the flange portion 22 of the magnetic core 20 shown in FIG. 3 in a plan view shown in FIG. 12, and the magnetic core 20 and the base member 30 are combined. The third coil 11 c is wound around a gap around the body 21 of the magnetic core 20 sandwiched between the ridge 22 and the ridge 34.

As described above, the winding axis of the third coil 11c is orthogonal to the mounting surface. Further, the second coil 11b is wound around the body portion 21 of the magnetic core 20 and the base member 30 so that the winding axis thereof is orthogonal to the winding axis of the third coil 11c. Furthermore, the first coil 11a is wound around the body 21 and the base member 30 of the magnetic core 20 so that the winding axis is orthogonal to the winding axis of the third coil 11c and the winding axis of the second coil 11b.

A plurality of columnar protrusions 50 are provided at the boundary between the upper surface (mounting surface) of the mounting portion 33 and the flange portion 34. As shown in FIGS. 10 and 12, the plurality of columnar protrusions 50 are provided at positions surrounding the body 21 of the magnetic core 20 when the magnetic core 20 and the base member 30 are combined. More specifically, when the magnetic core 20 and the base member 30 are combined, the plurality of columnar protrusions 50 are provided at positions where they fit with the recess 21 d provided in the body portion 21 of the magnetic core 20. .

FIG. 16 is an enlarged plan view showing the boundary position between the upper surface of the mounting portion 33 and the ridge portion 34. FIG. 17 is an enlarged view of the boundary position between the upper surface of the mounting portion 33 and the ridge portion 34 It is a perspective view shown. As shown in FIGS. 16 and 17, the side surface 50a on the side of the mounting portion 33 and the side surface 50b on the side of the flange portion 34 of the protrusion 50 are both curved in a cylindrical side shape. When the projection 50 is fitted in the recess 21 d of the trunk 21, the side surface 50 a of the projection 50 is in close contact with the surface of the recess 21 d of the trunk 21 without a gap. Further, the side surface 50 b on the side of the ridge portion 34 of the protrusion 50 is formed continuously with the ridge portion 34.

The magnetic core 20 and the base member 30 as described above are combined to form an assembly. In order to form an assembly, the bottom surface of the body portion 21 of the magnetic core 20 is fixed to the top surface of the mounting portion 33 of the base member 30 with an adhesive. Further, at this time, the projection 50 of the base member 30 is combined with the recess 21 d of the body 21 of the magnetic core 20.

FIG. 18 is a side view showing a state in which the magnetic core 20 and the base member 30 are combined, and FIG. 19, FIG. 20 and FIG. 21 are a perspective view, a plan view and a bottom view showing this state, respectively.

In a state where the magnetic core 20 and the base member 30 are combined, the first coil 11a is wound around the concave portion 21b of the magnetic core 20 and the concave portion 33b of the mounting portion 33 with the Y direction as the longitudinal direction. Further, the second coil 11b is wound around the recess 21a of the magnetic core 20 and the recess 33a of the mounting portion 33 with the X direction as the longitudinal direction. Furthermore, as shown in FIG. 18, since a gap of length T 7 is formed between the ridge 22 of the magnetic core 20 and the ridge 34 of the base member 30, the gap of the magnetic core 20 is formed using this gap. The third coil 11 c is wound around the body 21. As described above, since the first coil 11a and the second coil 11b are wound around the magnetic core 20 and the base member 30 with the Y direction and the X direction as the longitudinal direction, the magnetic core 20 and the base member 30 are in the Z direction. It will be firmly combined with

Further, since the bottom surface of the magnetic core 20 is flat and the mounting surface of the base member 30 on which the bottom surface is mounted is also flat, the ridge portion 22 of the magnetic core 20 and the base are compared as compared to the case where both magnetic cores are used. The distance T7 between the flange 30 and the member 30 can be increased. As a result, the number of turns of the third coil 11 c can be increased without increasing the height of the coil antenna 1. That is, while suppressing the height of the coil antenna 1, the self-inductance can be increased without reducing the quality factor Q of the coil. Therefore, it is possible to form a coil antenna having a small reception sensitivity difference in all directions.

FIG. 22 is a view for explaining the case where the base member 30 is warped. FIG. 23 is an enlarged view of the vicinity of the fitting portion between the protrusion 50 and the recess 21 d. As shown by a thick arrow in FIG. 22, when the base member 30 is warped, it is conceivable that a gap is generated between the magnetic core 20 and the base member 30. However, according to the present embodiment, as shown in FIG. 23, the protrusion 50 provided on the base member 30 and the recess 21 d of the body 21 of the magnetic core 20 are fitted. Since the projection 50 has a predetermined height in the Z direction, the base member 30 is warped, and even if a slight gap is formed between the magnetic core 20 and the base member 30 in the Z direction, The side surface portion of the body portion 21 around which the third coil 11c is wound is covered by the side surface of the body portion 21 and the projection 50, and the third coil 11c may enter between the magnetic core 20 and the base member 30. Absent.

In particular, as shown in FIG. 9, the recess 21 d of the body 21 of the magnetic core 20 is provided at a portion corresponding to the octagonal prism ridge. When the third coil 11c is wound around an octagonal prism, the third coil 11c is likely to receive a local force from the ridge line portion. However, in the present embodiment, the recess 21 d of the trunk portion 21 is provided in a portion corresponding to the ridge line of the octagonal prism, and the recess 21 d and the projection 50 of the base member 30 are fitted. Further, the side surface of the protrusion 50 on the side of the ridge portion 34 is curved in a cylindrical side shape. Therefore, the third coil 11c penetrates between the magnetic core 20 and the base member 30 while reliably preventing disconnection of the third coil 11c without receiving a local force from the protrusion 50. Can be prevented.

As described above, according to the present embodiment, in the coil antenna 1 using the magnetic core 20 and the base member 30, columnar protrusions are provided on the upper surface (mounting surface) of the mounting portion of the magnetic core 20 in the base member 30. Since 50 is provided, even when the base member 30 is warped, the third coil 11 c can be prevented from entering between the magnetic core 20 and the base member 30.

"The first coil 11a is wound around the outer periphery of the body 21" means that the first coil is not only wound when being in contact with the body 21, but only in contact with the projection 50. Including when wound without touching. The first coil 11 a preferably includes at least one or more turns of the coil wound in contact with only the protrusion 50 without being in contact with the body portion 21.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 24 is a perspective view showing an appearance of a base member 30A in the present embodiment. 25 and 26 are perspective views showing a state in which the magnetic core 20 and the base member 30A in the present embodiment are combined.

In the present embodiment, as shown in FIG. 24, the base member 30A is not integrally formed but divided into four. Even in such a case, as shown in FIGS. 25 and 26, the base member 30A can be combined with the bottom of the magnetic core 20.

Also in the present embodiment, the base member 30A is provided with a protrusion 50 similar to that of the first embodiment.

When the base member 30A is divided as in the present embodiment, processing is facilitated and the material cost can be reduced as compared with the case where the complex shaped base member 30 is formed as in the first embodiment. Therefore, the manufacturing cost can be reduced.

According to the present embodiment, in the coil antenna 1 using the magnetic core 20 and the base member 30, the third coil 11c enters between the magnetic core 20 and the base member 30 even when the base member 30A is warped. Can be prevented.

<Modification>
In the embodiment described above, an aspect in which the body portion 21 of the magnetic core 20 is an octagonal pole has been described as an example, but the present invention is not limited to such an aspect. You may use the trunk | drum 21 of polygonal cylinders other than an octagonal pillar. In this case, a concave portion may be provided in a portion corresponding to the ridge line of the polygonal prism so as to be fitted with the projection provided on the base member.
Although the core 20 is made of ferrite, the present invention is not limited to such an embodiment. As long as it is an insulator, another material may be used, and for example, a nonmagnetic material such as ceramic may be used. Moreover, a ferrite may be used for the trunk | drum 21 of the magnetic core 20, and resin may be used for the collar part 22 in order to raise intensity | strength, you may combine multiple types of materials.

In the second embodiment, as an example, the aspect in which the base member is divided into four has been described. However, the present invention is not limited to such an aspect, and the base member may be divided into two.

In each embodiment mentioned above, although the mode to which the present invention was applied was explained about a 3-axis coil antenna, the present invention is not limited to such a mode. For example, the present invention is also applicable to a single axis coil antenna. The uniaxial coil antenna in this case is wound around the outer periphery of the core of the core.

The above description of the embodiments is illustrative in all respects and not restrictive. Modifications and variations are possible as appropriate to those skilled in the art. The scope of the present invention is indicated not by the embodiments described above but by the claims. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope of the claims and equivalents.

The present invention is applicable in the field of a coil antenna combining a core provided with a body and a base member.

DESCRIPTION OF SYMBOLS 1 coil antenna 11a 1st coil 11b 2nd coil 11c 3rd coil 20 magnetic core 20d recessed part 21 body part 22 flange part 30 base member 50 protrusion

Claims

A magnetic core having a body;
A base member having a mounting surface on which the magnetic core is mounted, and one end of the body in the thickness direction being disposed on the mounting surface;
A coil antenna comprising: a first coil wound on an outer periphery of the body and disposed on the mounting surface when viewed in plan from the thickness direction;
The base member is provided on the mounting surface, and includes a protrusion disposed between the magnetic core and the first coil and protruding in the direction of the other end in the thickness direction of the body.
Coil antenna.
The magnetic core includes a recess provided on a side surface of the body portion,
The recess is formed from the one end of the body toward the other end, and has a shape fitted to the protrusion.
The coil antenna according to claim 1.
Comprising a plurality of said projections,
The first coil is wound around a plurality of turns around the body portion,
Among the plurality of turns, at least one turn is wound with the protrusion in contact without being in contact with the side surface of the body portion.
The coil antenna according to claim 1 or 2.
When viewed in plan from a direction orthogonal to the mounting surface described above, it has a curved portion curved on the side surface of the protrusion,
The first coil is in contact with the curved portion,
The coil antenna according to any one of claims 1 to 3.
Equipped with four or more of the protrusions,
When viewed in plan from one end of the magnetic core,
The body portion is disposed in a polygon having the four or more protrusions as apexes.
The coil antenna according to any one of claims 1 to 4.
The coil antenna further includes a second coil inside the first coil,
The second coil is wound around the magnetic core and the base member such that a winding axis of the second coil is orthogonal to a winding axis of the first coil.
The coil antenna according to any one of claims 1 to 5.
The coil antenna further includes a third coil inside the second coil,
The third coil is wound around the magnetic core and the base member such that a winding axis of the third coil is orthogonal to a winding axis of the first coil and a winding axis of the second coil.
The coil antenna according to any one of claims 1 to 4.