Antenna device

Abstract

This antenna device comprises: a case; a core which is housed in the case and has a magnetic body; a coil which is housed in the case and is wound around the core; and a cushion which is positioned between the case and the core, or the case and the coil. The area of a first contact surface between the case and the cushion is less than or equal to the area of a surface of the cushion, the surface being on a side facing the case.

Description

Antenna device

[0001] The present invention relates to an antenna device.

[0002] Patent Document 1 describes an antenna device that includes a wound body consisting of a magnetic core and a coil, a case that houses the wound body, and a foam that is filled between the wound body and the case.

[0003] International Publication No. 2007 / 015344

[0004] Incidentally, a cushion made of resin rubber or the like may be used instead of the foam described in Patent Document 1. In this case, if the cushion is formed to fit tightly against the case without any gaps, as with the foam, it becomes difficult to fit the cushion into the case, which can result in a long time required to assemble the antenna device.

[0005] One object of the present invention is to easily assemble an antenna device. Other objects of the present invention will become apparent from the description of this specification.

[0006] One aspect of the present invention is an antenna device comprising a case, a core having a magnetic material housed in the case, a coil housed in the case and wound around the core, and a cushion positioned between the case and the core or the coil, wherein the area of ​​a first contact surface between the case and the cushion is less than or equal to the area of ​​the surface of the cushion facing the case.

[0007] According to the above aspect of the present invention, the antenna device can be easily assembled.

[0008] FIG. 3 is a perspective view showing the antenna device 10 of the present embodiment with the case 11 removed. FIG. 4 is an exploded perspective view of the antenna device 10 of the present embodiment. FIG. 5 is a cross-sectional view of the YZ plane taken along line A-A in FIG. 1. FIG. 6 is an enlarged view of the dashed line portion in FIG. 3. FIG. 7 is a perspective view showing the antenna device 10A of the first modified example with the case 11A and housing 18A removed. FIG. 8 is a perspective view showing the antenna device 10B of the second modified example with the case 11B and housing 18B removed. FIG. 9 is an exploded perspective view of the antenna device 10C of the third modified example.

[0009] At least the following matters will become clear from the description of this specification and the accompanying drawings.

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc. shown in each drawing are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0011] ==Present Embodiment== Fig. 1 is a perspective view showing an antenna device 10 of this embodiment with a case 11 removed. Fig. 2 is an exploded perspective view of the antenna device 10 of this embodiment. Fig. 3 is a cross-sectional view of the YZ plane taken along line AA in Fig. 1.

[0012] <<Definition of Directions, Etc.>> First, directions, etc. in the antenna device 10 of this embodiment will be defined with reference to FIGS. 1, 2, and 3. FIG.

[0013] 1, 2, and 3, the direction from the core 12 (described below) toward the substrate 16 (described below) is defined as the "+Z direction," and the opposite direction (i.e., the direction from the substrate 16 toward the core 12) is defined as the "-Z direction." Furthermore, the direction from the core 12 toward the cushion first body 21 (described below) of the cushion 14 is defined as the "+Y direction," and the opposite direction (i.e., the direction from the cushion first body 21 of the cushion 14 toward the core 12) is defined as the "-Y direction." The directions perpendicular to the +Z direction and the +Y direction are defined as the "+X direction" and the "-X direction."

[0014] Each of the +X direction, -X direction, +Y direction, -Y direction, +Z direction, and -Z direction is a direction with a fixed orientation. Rather than being a fixed orientation as described above, both the +X direction and the -X direction may be simply referred to as the "X direction." Similarly, both the +Y direction and the -Y direction may be simply referred to as the "Y direction." Furthermore, both the +Z direction and the -Z direction may be simply referred to as the "Z direction."

[0015] 1, 2, and 3, the +X direction, +Y direction, and +Z direction are each represented by a line segment with an arrow to facilitate understanding of directions, etc., in the antenna device 10. Note that the intersection of these line segments with an arrow does not indicate the origin of the coordinate system.

[0016] The above definitions of directions and the like are common to other embodiments in this specification unless otherwise specified.

[0017] <<Outline of Antenna Device 10 >> Next, an outline of the antenna device 10 of this embodiment will be described with reference again to FIGS. 1, 2, and 3 described above.

[0018] The antenna device 10 is an antenna device having an LF (Low Frequency) antenna. The LF antenna in the antenna device 10 of this embodiment is used in a keyless entry system or a smart entry system that remotely locks and unlocks vehicle doors and trunks. The LF antenna in the antenna device 10 of this embodiment may also be used for engine start permission and auto-locking. However, the antenna device 10 may have an antenna compatible with radio waves of other communication standards and frequency bands than the LF band.

[0019] The antenna device 10 is attached to a predetermined location of the vehicle, such as inside a door panel, trunk, hatchback, mirror, or interior of the vehicle. However, the location where the antenna device 10 is attached can be changed as needed depending on the desired directivity, etc. The antenna device 10 may be attached to various locations, such as inside a door panel, trunk, hatchback, mirror, or interior of the vehicle, as well as the vehicle's windshield, rear window, inside the instrument panel, above the dashboard, overhead console, bumper, license plate attachment portion, pillar, spoiler, etc. Furthermore, multiple antenna devices 10 may be attached to a single vehicle, each for a different installation location.

[0020] Here, the antenna device 10 is not limited to being attached to a vehicle, but may also be brought into the vehicle and used within the vehicle. While the antenna device 10 of the present embodiment is described as being used in a "vehicle," which is a wheeled vehicle, the present invention is not limited to this, and may also be used in other mobile objects, such as drones and other flying objects, probes, construction machinery without wheels, agricultural machinery, and ships. Furthermore, the antenna device 10 may also be an antenna used for objects other than mobile objects, such as a surveying antenna, a reference station antenna, a transmitting antenna and a reference antenna in an anechoic chamber, etc.

[0021] The LF antenna in the antenna device 10 of this embodiment is compatible with radio waves in the LF band (e.g., 30 kHz to 300 kHz). However, the LF antenna in the antenna device 10 of this embodiment may be compatible with radio waves in a frequency band other than the 30 kHz to 300 kHz band. Furthermore, the antenna device 10 of this embodiment may have multiple LF antennas, or may have an antenna other than an LF antenna. The antenna included in the antenna device 10 may be compatible with radio waves in multiple frequency bands.

[0022] The antenna device 10 includes a case 11, a core 12, a coil 13, a cushion 14, a holder 15, a substrate 16, and a capacitor 17. As will be described later, the coil 13 wound around the core 12 and the capacitor 17 enable the antenna device 10 to handle radio waves in the LF frequency band. In the following description, the core 12, the coil 13, the cushion 14, the holder 15, the substrate 16, and the capacitor 17 may be collectively referred to as the "antenna main body."

[0023] The antenna main body of the antenna device 10 is connected to a connector (not shown) via a cable 19. That is, the antenna device 10 is a cable-type antenna device. However, as in a modified example described later (see FIGS. 5 and 6 ), the antenna device 10 may be a connector-type antenna device in which a connector is integrated.

[0024] The case 11 is a component that constitutes the exterior of the antenna device 10. The case 11 is formed in the shape of a rectangular parallelepiped cylinder elongated in the Z direction and with a bottom. An opening 110 is formed at the end of the case 11 on the +Z direction side. The opening 110 is an opening for accommodating the antenna main body inside the case 11. As will be described later, the antenna main body is accommodated inside the case 11, and a sealant such as silicone is filled on the side of the opening 110 and the sealant is allowed to harden. This allows the antenna main body accommodated inside the case 11 to be sealed. In other words, the antenna device 10 has a waterproof structure for the antenna main body.

[0025] Engagement holes 111 are formed on both the +Y direction side and the −Y direction side of the case 11. The edges of the engagement holes 111 are portions into which engagement claws 151 (described below) of the holder 15 engage. The edges of the engagement holes 111 engage with the engagement claws 151 of the holder 15, making it possible to assemble the case 11 and the holder 15 (specifically, the holder 15 that holds the cushion 14, the core 12 around which the coil 13 is wound, and the substrate 16 on which the capacitor 17 is mounted).

[0026] The case 11 is formed of an insulating resin such as PBT or ABS. However, the case 11 may be formed of a material other than insulating resin that transmits radio waves. Furthermore, the case 11 may be composed of an insulating resin portion and a portion of another material that transmits radio waves, and components may be freely combined.

[0027] The core 12 is a member having a magnetic body. The core 12 is formed of a magnetic material such as ferrite. However, the core 12 may be formed of a magnetic material other than ferrite. The core 12 is formed in a rectangular parallelepiped shape that is elongated in the Z direction. The core 12 is held by a holder 15 together with a coil 13 wound around the outer periphery of the core 12, and is housed in the case 11.

[0028] The coil 13 is a component that constitutes the inductance of the antenna body and is wound around the core 12. The coil 13 is wound around the core 12 about an axis along the Z direction, and has a dense region 131 with a large number of turns per unit length in the Z direction and a sparse region 132 with a smaller number of turns per unit length in the Z direction than the dense region 131.

[0029] As shown in FIG. 2 , the coil 13 in this embodiment has three dense regions 131 and two sparse regions 132 arranged alternately from the +Z direction side to the −Z direction side. In this embodiment, the number of dense regions 131 (three) is greater than the number of sparse regions 132 (two), but the number of sparse regions 132 may be greater than or equal to the number of dense regions 131. Furthermore, the coil 13 does not need to have dense regions 131 and sparse regions 132. For example, the coil 13 may be wound around the core 12 so that the number of turns per unit length in the Z direction is constant. That is, the manner in which the coil 13 is wound around the core 12 can be changed as appropriate depending on the desired antenna characteristics of the LF antenna.

[0030] As shown in FIG. 2 , one and the other ends of the coil 13 are located in the +Z direction and are connected to the substrate 16 by soldering. This electrically connects the coil 13 to electronic components, including the capacitor 17, on the substrate 16. The coil 13 wound around the core 12 and the substrate 16 on which the capacitor 17 is located are disposed adjacent to each other. That is, the antenna device 10 does not have a connecting portion or the like between the coil 13 and the substrate 16. By disposing the coil 13 and the substrate 16 adjacent to each other (the antenna device 10 does not have a connecting portion or the like between the coil 13 and the substrate 16), the size (particularly the length in the Z direction) of the core 12 and the coil 13 can be increased without changing the overall size of the antenna device 10. This improves the antenna performance of the antenna device 10 and reduces the number of components in the antenna device 10.

[0031] The cushion 14 is a member that suppresses transmission of external force applied to the antenna device 10 from the case 11 to the inside of the cushion 14 in the antenna body. The cushion 14 also serves to absorb impact force when the antenna device 10 is dropped. By including the cushion 14 in the antenna device 10, for example, changes in the winding state of the coil 13 and damage to the core 12 caused by external force applied to the antenna device 10 can be suppressed, and changes in inductance can be suppressed.

[0032] The cushion 14 is made of an elastic material such as TPE or rubber (NBR, EPDM, etc.), but the cushion 14 may be made of other elastic materials.

[0033] The cushion 14 has a first cushion body 21, a second cushion body 22, and a connecting portion 23. The first cushion body 21 is a portion of the cushion 14 located on the +Y direction side (i.e., on one side relative to the core 12). The second cushion body 22 is a portion of the cushion 14 located on the −Y direction side (i.e., on the opposite side relative to the core 12).

[0034] The connection portion 23 is a portion that connects the first cushion body 21 and the second cushion body 22. By connecting the first cushion body 21 and the second cushion body 22 by the connection portion 23, it is possible to suppress external forces transmitted to the core 12 on both sides of the core 12 (on both sides in the Y direction in this embodiment). The cushion 14 has a plurality of connection portions 23 on the side surfaces of the core 12 (on the sides perpendicular to the Y direction).

[0035] As shown in FIG. 3 , of the multiple connection portions 23, the connection portion 23 located on the −Z direction side has a protrusion 230. The protrusion 230 is a part for positioning the core 12 within the case 11. The protrusion 230 protrudes in the +Z direction from the surface of the connection portion 23 on the +Z direction side, and has a surface (corresponding to a “positioning abutment surface”) that abuts against the core 12 at the end of the protrusion 230 on the +Z direction. However, the connection portion 23 located on the −Z direction side may not have the protrusion 230 (the surface on the +Z direction is flat), and the surface on the −Z direction side of the core 12 may protrude in the −Z direction to have a surface (positioning abutment surface) where the connection portion 23 and the core 12 abut. Because the connection portion 23 has a surface that abuts against the core 12, when the antenna main body including the core 12 is housed in the case 11, the core 12 and coil 13 can be easily positioned in the Y direction within the case 11, thereby reducing the possibility of the core 12 and coil 13 being damaged within the case 11.

[0036] Further details of the cushion 14 will be described later.

[0037] The holder 15 is a member that holds the cushion 14, the core 12 around which the coil 13 is wound, and the substrate 16 on which the capacitor 17 is mounted. The holder 15 holds the core 12 around which the coil 13 is wound via the cushion 14, and holds the substrate 16 attached to the holder 15 by snap-fitting. However, the holder 15 may also hold the substrate 16 attached by press-fitting instead of snap-fitting.

[0038] In this embodiment, the holder 15 holds the board 16 by snap-fitting, so the board 16 is not completely fixed (i.e., the board 16 is allowed to move to a certain extent relative to the holder 15). Therefore, even if an external force is applied to the antenna body, it is possible to prevent the stress from being directly transmitted to the board 16 itself. This makes it possible to prevent the electronic components from peeling off from the soldered portions of the board 16.

[0039] The holder 15 has an engaging claw 151 , a protrusion 152 , an arm 153 , and a board mounting surface 154 .

[0040] The engagement claws 151 are portions that engage with the edges of the engagement holes 111 of the case 11. By engaging the engagement claws 151 with the edges of the engagement holes 111, it is possible to assemble the case 11 and the holder 15 (specifically, the holder 15 that holds the cushion 14, the core 12 around which the coil 13 is wound, and the substrate 16 on which the capacitor 17 is mounted).

[0041] The protrusion 152 is a part that holds the substrate 16, which is attached to the holder 15 by a snap fit, from the +Y direction side together with the arm 153. The protrusion 152 is formed to protrude in the -Z direction. A notch (not shown) is formed in the end of the substrate 16 on the -Z direction side, and the protrusion 152 engages with this notch on the -Z direction side of the substrate 16, thereby preventing movement in the X direction of the substrate 16, which is attached to the holder 15 by a snap fit.

[0042] The arm 153 is a portion that holds the substrate 16 attached to the holder 15 by snap-fitting from the +Y direction side together with the protrusion 152. The arm 153 is formed so as to protrude in the +Z direction side and is formed so as to be elastically deformable in the -Z direction side.

[0043] The substrate mounting surface 154 is a portion that holds the substrate 16 from the −Y direction side. By bringing the substrate 16 into contact with the surface of the substrate mounting surface 154 on the +Y direction side, the substrate mounting surface 154 holds the substrate 16 from the −Y direction side.

[0044] The substrate 16 is a substrate on which electronic components including the capacitor 17 are arranged. The substrate 16 is, for example, a printed circuit board (PCB). In the antenna device 10 of this embodiment, the substrate 16 is a rigid substrate, but is not limited to this and may be a flexible substrate. In addition to the capacitor 17 and the ground pattern, circuit elements such as a filter may also be separately arranged on the substrate 16.

[0045] Capacitor 17 is a component that constitutes the capacitance of the antenna body. Capacitor 17 is mounted on substrate 16 by soldering or the like. The capacitance formed by capacitor 17 and the inductance formed by coil 13 wound around core 12 enable the antenna body to respond to radio waves in the above-mentioned LF frequency band (e.g., 30 kHz to 300 kHz).

[0046] <<Details of Cushion 14 >> Hereinafter, the detailed configuration of the cushion 14 will be described with reference again to FIGS. 1, 2, and 3 described above, and also with reference to FIG. 4 .

[0047] FIG. 4 is an enlarged view of the dashed line portion of FIG.

[0048] The cushion first body 21 has a protrusion 210, a first leg 211, and a second leg 212. The cushion second body 22 has a protrusion 220, a first leg 221, and a second leg 222. The protrusion 220, the first leg 221, and the second leg 222 of the cushion second body 22 are described in the same manner as the protrusion 210, the first leg 211, and the second leg 212 of the cushion first body 21, unless otherwise specified.

[0049] The protrusion 210 of the cushion first body 21 is a portion that protrudes more than other portions on the surface on the +Y direction side of the cushion first body 21. The end of the protrusion 210 on the +Y direction side abuts against the inner surface (the surface on the -Y direction side) of the case 11. The cushion first body 21 has multiple protrusions 210 (two in this embodiment). However, the cushion first body 21 may have only one protrusion 210, or may have three or more protrusions 210.

[0050] Furthermore, the protrusion 220 of the cushion second main body 22 is a portion that protrudes more than other portions on the surface of the cushion second main body 22 on the -Y direction side. The end of the protrusion 220 on the -Y direction side abuts against the inner surface of the case 11 (the surface on the +Y direction side). The cushion second main body 22 has multiple protrusions 220 (two in this embodiment). However, the cushion second main body 22 may have only one protrusion 220, or may have three or more protrusions 220.

[0051] Hereinafter, the contact surface between the cushion 14 and the case 11 may be referred to as the "first contact surface 31." A plurality of (two in this embodiment) protrusions 210 contact the inner surface of the case 11 (the surface on the -Y direction side), and a plurality of (two in this embodiment) protrusions 220 contact the inner surface of the case 11 (the surface on the +Y direction side). Therefore, the first contact surface 31 is a surface formed by combining the contact surfaces between the plurality of protrusions 210 and the case 11 and the contact surfaces between the plurality of protrusions 220 and the case 11.

[0052] However, if the surface of the cushion 14 facing the case 11 (in this embodiment, the surface on the +Y direction side of the cushion first main body 21 and the surface on the −Y direction side of the cushion second main body 22) is formed so as to fit tightly against the inner surface of the case 11 without any gaps, it may become difficult to store the cushion 14 in the case 11. This is because a large force is required to store the cushion 14 in the case 11 due to friction between the contact surfaces of the cushion 14 and the case 11. In particular, if the cushion 14 is made of an elastic material such as rubber, the friction between the contact surfaces of the cushion 14 and the case 11 will be large.

[0053] Therefore, in this embodiment, the cushion 14 has a surface facing the case 11 (in this embodiment, the surface on the +Y direction side of the cushion first body 21 and the surface on the −Y direction side of the cushion second body 22) where only a portion of the surface facing the case 11 abuts against the inner surface of the case 11, thereby reducing friction caused by the abutting surfaces of the cushion 14 and the case 11. This allows the cushion 14 to be easily accommodated in the case 11, and the antenna device 10 to be easily assembled.

[0054] In the above-described embodiment, an example has been described in which the cushion 14 has the protrusion 210 and abuts against the flat inner surface of the case 11, but the surface of the cushion 14 facing the case 11 (in the present embodiment, the surface on the +Y direction side of the cushion first main body 21 or the surface on the −Y direction side of the cushion second main body 22) may be flat, and a protrusion may be formed on the inner surface of the case 11. Even in this case, by abutting only a portion of the surface of the case 11 facing the cushion 14 (in the present embodiment, the protrusion of the case 11) against the cushion 14 on the surface facing the cushion 14 (in the present embodiment, the inner surface of the case 11), it is possible to reduce friction caused by the abutting surfaces between the cushion 14 and the case 11.

[0055] Furthermore, both the cushion 14 and the case 11 have protrusions, and the protrusions of the cushion 14 and the protrusions of the case 11 come into contact with each other, thereby reducing friction caused by the contact surfaces of the cushion 14 and the case 11.

[0056] As described above, in this embodiment, the area S1 of the first contact surface 31 between the case 11 and the cushion 14 is equal to or smaller than the area SA (see FIG. 2 ) of the surface of the cushion 14 facing the case 11 (S1≦SA). Here, in this embodiment, the area S1 of the first contact surface 31 is the sum of the area of ​​the contact surface between the plurality of protrusions 210 and the case 11 and the area of ​​the contact surface between the plurality of protrusions 220 and the case 11. Also, in this embodiment, the area SA is the sum of the area of ​​the surface of the cushion first body 21 facing the case 11 and the area of ​​the surface of the cushion second body 22 facing the case 11. This allows the cushion 14 to be easily accommodated in the case 11, and the antenna device 10 to be easily assembled.

[0057] The first leg 211 and the second leg 212 of the cushion first body 21 are each a portion that protrudes more than other portions on the surface of the cushion first body 21 on the -Y direction side. The first leg 211 is located on the +Z direction side, and the second leg 212 is located on the -Z direction side. However, the cushion first body 21 may have only one leg (protrusion) instead of multiple legs like the first leg 211 and the second leg 212. The -Y direction end of each of the first leg 211 and the second leg 212 abuts against the surface of the core 12 on the +Y direction side. The cushion first body 21 has multiple combinations of the first leg 211 and the second leg 212 (two in this embodiment). However, the cushion first body 21 may have only one combination of the first leg 211 and the second leg 212, or three or more combinations.

[0058] Furthermore, each of the first leg 221 and the second leg 222 of the cushion second body 22 is a portion that protrudes more than other portions on the surface of the cushion second body 22 on the +Y direction side. The first leg 221 is located on the +Z direction side, and the second leg 222 is located on the -Z direction side. However, the cushion second body 22 may have only one leg (protrusion) instead of multiple legs like the first leg 221 and the second leg 222. The +Y direction end of each of the first leg 221 and the second leg 222 abuts on the surface of the core 12 on the -Y direction side. The cushion second body 22 has multiple combinations of the first leg 221 and the second leg 222 (two in this embodiment). However, the cushion second body 22 may have only one combination of the first leg 221 and the second leg 222, or three or more combinations.

[0059] Hereinafter, the contact surface between the cushion 14 and the core 12 may be referred to as the "second contact surface 32." In this embodiment, a combination of multiple (two in this embodiment) first legs 211 and second legs 212 contacts the surface of the core 12 on the +Y direction side, and a combination of multiple (two in this embodiment) first legs 221 and second legs 222 contacts the surface of the core 12 on the -Y direction side. Therefore, the second contact surface 32 is the surface where the contact surfaces of these multiple legs and the core 12 join together.

[0060] As described above, the coil 13 is wound around the core 12. The second contact surface 32 is located in the sparse region 132, not the dense region 131, of the coil 13 wound around the core 12. That is, the ends of the multiple legs of the cushion 14 contact at least a part of the sparse region 13F2 of the coil 13 wound around the core 12.

[0061] Here, in the present embodiment, the cushion first body 21 includes a plurality of legs (two legs, a first leg 211 and a second leg 212, in this embodiment) corresponding to a certain protrusion 210, and the ends of each of the plurality of legs abut against the core 12. In other words, in this embodiment, there is one portion where the cushion 14 and the case 11 abut (the protrusion 210, in this embodiment), while there are two portions where the cushion 14 and the core 12 abut (the first leg 211 and the second leg 212, in this embodiment). Also, the number of portions where the cushion 14 and the core 12 abut (two, in this embodiment) is greater than the number of portions where the cushion 14 and the case 11 abut (one, in this embodiment). This disperses external forces transmitted to the core 12, thereby further preventing damage to the core 12.

[0062] In the case of the cushion first body 21, in the above-described embodiment, an example was described in which the cushion 14 has a first leg 211 and a second leg 212 and abuts against the flat surface of the core 12, but the surface of the cushion 14 facing the core 12 (in this embodiment, the surface on the -Y direction side of the cushion first body 21) may be flat, and legs (protrusions) may be formed on the surface of the core 12 facing the cushion 14.

[0063] Furthermore, both the cushion 14 and the core 12 have legs (protrusions), and the legs (protrusions) of the cushion 14 abut against the legs (protrusions) of the core 12, thereby dispersing the external force transmitted to the core 12 and further preventing damage to the core 12.

[0064] In this embodiment, the second abutment surface 32 reduces the impact force when the antenna device 10 is dropped, thereby suppressing damage to the core 12 and suppressing changes in the antenna inductance of the antenna device 10. Furthermore, the area S2 of the second abutment surface 32 is larger than the area S1 of the first abutment surface 31 (S2 > S1). This allows for more stable protection of the core 12. However, the area S2 of the second abutment surface 32 may be the same as the area S1 of the first abutment surface 31 (S2 = S1) or may be smaller (S2 < S1). Here, in this embodiment, the area S2 of the second abutment surface 32 is the total area of ​​the abutment surfaces between all legs of the cushion 14 and the core 12.

[0065] <<Assembly Procedure of Antenna Device 10>> Below, the assembly procedure of the antenna device 10 will be described with reference again to the above-mentioned Figures 1, 2, 3, and 4. The antenna device 10 according to this embodiment is manufactured through the following six steps.

[0066] (1) Mounting the capacitor 17 on the substrate 16; (2) Mounting the substrate 16 with the capacitor 17 mounted on the holder 15; (3) Mounting the core 12 on the holder 15; (4) Winding the coil 13 around the core 12 mounted on the holder 15; (5) Mounting the cushion 14; and (6) Enclosing the case 11.

[0067] These six steps are arranged in the above order for the sake of convenience, but the above order may be changed as appropriate. Each step will be described in detail below.

[0068] (1) Mounting the capacitor 17 on the substrate 16 First, the substrate 16 is prepared, and the capacitor 17 is mounted by soldering. Here, for example, the capacitor 17 can be mounted directly on a metal terminal instead of on the substrate 16. However, mounting the capacitor 17 on a metal terminal may apply stress to the capacitor 17, which may result in damage to the capacitor 17. Furthermore, solderability may be poor when connecting the capacitor 17 to the metal terminal, and the metal terminal may need to be separated later. Therefore, mounting the capacitor 17 on the substrate 16 as in this embodiment can prevent damage to the capacitor 17 and improve assembly workability.

[0069] Furthermore, by attaching the capacitor 17 to the substrate 16, it can be easily attached to the holder 15 by snap-fitting or press-fitting in the procedure (2) described below (attaching the substrate 16 with the attached capacitor 17 to the holder 15).

[0070] (2) Attaching the Substrate 16 with the Capacitor 17 Attached to the Holder 15 As described above, the substrate 16 with the capacitor 17 attached is attached to the holder 15 by snap-fitting. In FIG. 3 , the outline of the substrate 16 before attachment is indicated by a dashed line. To attach the substrate 16 to the holder 15 by snap-fitting, as shown in FIG. 3 , the end of the substrate 16 on the −Z direction side is hooked onto the arm 153 of the holder 15, and the end of the substrate 16 on the +Z direction side is moved toward the −Y direction. Then, the arm 153 is elastically deformed toward the −Z direction by the pressing force of the end of the substrate 16 on the −Z direction side hooked onto the arm 153, and the substrate 16 is positioned so that the end of the substrate 16 on the +Z direction side is located toward the −Y direction side of the protrusion 152.

[0071] However, the method of attaching the substrate 16 to the holder 15 is not limited to snap-fitting, and may be press-fitting, for example. As a method of attaching the substrate 16 to the holder 15 by press-fitting, a method may be used in which a resin protrusion is formed on the holder 15 and the substrate 16 is press-fitted into this protrusion to be fixed. Attaching the substrate 16 to the holder 15 by snap-fitting or press-fitting eliminates the need for welding or adhesive, and the substrate 16 can be easily attached to the holder 15. However, the substrate 16 may also be attached by a method in which a resin protrusion is formed on the holder 15 and the protrusion is inserted into a hole formed in the substrate 16 and thermally welded.

[0072] (3) Attaching the core 12 to the holder 15 (4) Winding the coil 13 around the core 12 attached to the holder 15 Next, after attaching the core 12 to the holder 15, the coil 13 is wound around the core 12 attached to the holder 15. Thereafter, the cable 19 is inserted into the hole of the holder 15, and the end of the coil 13 and the end of the cable 19 are connected to the substrate 16 by soldering.

[0073] (5) Attaching the cushion 14 Next, the cushion 14 is attached to the core 12 around which the coil 13 is wound from the outside of the holder 15. The cushion 14 has a first cushion body 21 and a second cushion body 22, and is attached so as to hold the core 12 from both sides, which prevents the cushion 14 from easily falling off the core 12.

[0074] (6) Housing in Case 11 Finally, the antenna main body (core 12 around which coil 13 is wound, cushion 14, holder 15, and substrate 16 on which capacitor 17 is arranged) is housed in case 11. After the antenna main body is housed inside case 11, a sealant such as silicone is filled on the side of opening 110 of case 11, and the sealant is allowed to harden. This allows the antenna main body housed inside case 11 to be sealed.

[0075] <<Modifications>> The antenna device 10 of the above-described embodiment is a cable-type antenna device that is connected to a connector (not shown) via a cable 19. However, as in the modification described below, the antenna device may be a connector-type antenna device in which a connector is integrated. Two examples (a first modification and a second modification) of the connector-type antenna device will be described below.

[0076] FIG. 5 is a perspective view showing the antenna device 10A of the first modified example with the case 11A and the housing 18A removed.

[0077] The antenna device 10A has an exterior that is made up of a case 11A and a housing 18A, and other components (core 12, coil 13, cushion 14, holder 15, substrate 16, and capacitor 17) housed in it. Instead of the cable 19 of this embodiment, the antenna device 10A is provided with a terminal 19A that is connected to the substrate 16 and extends in the +Z direction.

[0078] The terminals 19A are inserted into holes (not shown) in the housing 18A, thereby forming a connector surface on the +Z direction side of the housing 18A.

[0079] An engagement hole 111A is formed on each of the +Y direction side and the -Y direction side of the case 11A. The engagement hole 111A is a portion whose edge engages with an engagement claw 181A (described later) of the housing 18A. The housing 18A has an engagement claw 181A on each of the +Y direction side and the -Y direction side. The engagement claw 181A is a portion that engages with the edge of the engagement hole 111A of the case 11A. The engagement claw 181A engages with the edge of the engagement hole 111A, making it possible to assemble the case 11A and the housing 18A.

[0080] The other configurations are the same as those of the antenna device 10 of this embodiment. Even in the antenna device 10A of the first modified example, the cushion 14 can be easily housed in the case 11A, and the antenna device 10A can be easily assembled.

[0081] FIG. 6 is a perspective view showing an antenna device 10B of the second modified example with the case 11B and the housing 18B removed.

[0082] The antenna device 10A has an exterior that is made up of a case 11B and a housing 18B, and other components (core 12, coil 13, cushion 14, holder 15, substrate 16, and capacitor 17) housed in it. Similar to the antenna device 10A of the first modified example, the antenna device 10B is connected to the substrate 16 and has a terminal 19B disposed thereon. However, the terminal 19B is disposed so as to extend in the -X direction. Also, similar to the antenna device 10A of the first modified example, the case 11B and the housing 18B can be assembled together by engaging the engagement claw 181B with the edge of the engagement hole 111B.

[0083] The other configurations are the same as those of the antenna device 10 of this embodiment. Even in the antenna device 10B of the first modified example, the cushion 14 can be easily housed in the case 11B, and the antenna device 10B can be easily assembled.

[0084] In the antenna device 10 of the present embodiment described above, the coil 13 is wound around the core 12 attached to the holder 15, and the cushion 14 is attached. At this time, the ends of the multiple legs of the cushion 14 are in contact with at least a part of the sparse region 132 of the coil 13 wound around the core 12. However, as in a third modified example described later, the ends of the multiple legs do not have to be in contact with the sparse region 132 of the coil 13. In other words, the cushion 14 may not be in contact with the coil 13, but may be in contact only with the core 12.

[0085] FIG. 7 is an exploded perspective view of an antenna device 10C according to a third modified example.

[0086] The antenna device 10C of the third modification has a similar shape to the antenna device 10 of the present embodiment, except that the position of the sparse region 132C in the coil 13C relative to the core 12 is different. The coil 13C has a dense region 131C and a sparse region 132C. The dense region 131C is wound around the core 12, as in the antenna device 10 of the present embodiment, but the sparse region 132C is wound around the outside of the holder 15 (specifically, the side surface of the holder 15 facing in the X direction). This allows the cushion 14 to be positioned so that it does not contact the coil 13 and only contacts the core 12. This prevents changes in the winding state of the coil 13 and damage to the core 12 due to contact of the cushion 14 with the coil 13.

[0087] The other configurations of the antenna device 10C of the third modified example are the same as those of the antenna device 10 of the present embodiment. Even in the antenna device 10C of the third modified example, the cushion 14 can be easily housed in the case 11, and the antenna device 10C can be easily assembled.

[0088] Summary According to the present specification, there is provided an antenna having the following aspects.

[0089] (Aspect 1) Aspect 1 is an antenna device comprising a case, a core housed in the case and having a magnetic body, a coil housed in the case and wound around the core, and a cushion located between the case and the core or the coil, wherein the area of ​​a first contact surface between the case and the cushion is equal to or less than the area of ​​the surface of the cushion facing the case.

[0090] According to the above-described aspect, the antenna device can be easily assembled.

[0091] (Aspect 2) In aspect 2, a second contact surface is provided on the cushion opposite to the first contact surface, where the core and the cushion come into contact with each other.

[0092] According to the above-described aspect, by mitigating the impact force when the antenna device is dropped, it is possible to suppress damage to the core and suppress changes in the inductance of the antenna in the antenna device.

[0093] (Aspect 3) In aspect 3, the area of ​​the second contact surface is larger than the area of ​​the first contact surface.

[0094] According to the above-described aspect, the core can be protected more stably.

[0095] (Aspect 4) In aspect 4, the cushion includes a plurality of legs, and an end of each of the plurality of legs abuts against the core.

[0096] According to the above-described aspect, external forces transmitted to the core can be dispersed, and damage to the core can be further suppressed.

[0097] (Aspect 5) In aspect 5, the cushion has a cushion first body located on one side of the core, a cushion second body located on the opposite side of the core from the one side, and a connecting portion connecting the cushion first body and the cushion second body.

[0098] According to the above-described aspect, it is possible to suppress external forces transmitted to the core on both sides of the core.

[0099] (Aspect 6) In aspect 6, the connection portion includes a positioning abutment surface that determines the position of the core within the case.

[0100] According to the above-described aspects, it is possible to easily position the core 12 and the coil 13 within the case. (Aspect 7) Aspect 7 includes a holder and a substrate, and the substrate is attached to the holder by snap-fitting or press-fitting.

[0101] According to the above-described aspect, the substrate can be easily attached to the holder.

[0102] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. Furthermore, the present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof.

[0103] 10, 10A, 10B, 10C Antenna device, 11, 11A, 11B Case, 12 Core, 13, 13C Coil, 14 Cushion, 15 Holder, 16 Board, 17 Capacitor, 18A, 18B Housing, 19 Cable, 19A, 19B Terminal, 21 Cushion first body, 22 Cushion second body, 23 Connection portion, 31 First contact surface, 32 Second contact surface, 110 Opening, 111, 111A, 111B Engagement hole, 131, 131C Dense area, 132, 132C Sparse area, 151 Engagement claw, 152 Protrusion, 153 Arm, 154 Board mounting surface, 181A, 181B Engagement claw, 210, 220, 230 Protrusion, 211, 221 1st leg, 212, 222 2nd leg

Claims

1. An antenna device comprising: a case; a core having a magnetic material housed in the case; a coil housed in the case and wound around the core; and a cushion located between the case and the core or the coil, wherein the area of ​​a first abutment surface between the case and the cushion is less than or equal to the area of ​​a surface of the cushion facing the case.

2. The antenna device according to claim 1, further comprising a second contact surface, on the side of the cushion opposite to the first contact surface, where the core and the cushion come into contact.

3. The antenna device according to claim 2, wherein an area of ​​the second contact surface is larger than an area of ​​the first contact surface.

4. The antenna device according to claim 3, wherein the cushion includes a plurality of legs, each end of the plurality of legs abutting against the core.

5. The antenna device as described in claim 1, wherein the cushion has: a first cushion body located on one side of the core; a second cushion body located on the opposite side of the core from the one side; and a connecting portion connecting the first cushion body and the second cushion body.

6. The antenna device according to claim 5, wherein the connection portion includes a positioning abutment surface that determines the position of the core within the case.

7. The antenna device according to claim 1 or 6, comprising a holder and a substrate, the substrate being attached to the holder by snap-fitting or press-fitting.

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