JP2008011137A - Antenna unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna unit easy to attach an antenna element. <P>SOLUTION: When an antenna element 36 is attached to a second cover member 24 at the antenna unit, an insert axis 32 (small diameter portion 32B) is inserted into a through-hole 38, and a pair of engagements 34 are inserted into a pair of engagement insert holes 40. Consequently, movement of the antenna element 36 to the radial direction in relation to the insert axis 32 is restricted. In addition, if the antenna element 36 rotates relatively around the insert axis 32 in relation to the second cover member 24 under a condition that the stage 32C of the insert axis 32 contacts at a hole rim of the through-hole 38, a hole rim of the pair of engagement insert holes 40 is inserted into each groove 34A of the pair of engagements 34, and axial directional movement of the antenna element 36 is restricted in relation to the insert axis 32. According to the arrangement, the antenna element 36 is supported by the second cover member 24. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna device for wireless communication.

  Some vehicles such as automobiles are equipped with an automatic toll collection system (hereinafter referred to as an ETC device) that automatically settles tolls on toll roads by wireless communication. Such an ETC device includes an antenna device for wirelessly transmitting / receiving information to / from a transmission / reception antenna installed at a toll gate on a toll road (see, for example, Patent Document 1 or Patent Document 2). As such an antenna device, an electromagnetic coupling type antenna device may be used.

An electromagnetic coupling type antenna device used for an ETC device has, for example, a substrate assembled inside an antenna cover and an antenna element screwed to the substrate via a spacer.
JP 2003-291726 A JP 2005-170319 A

  Since the antenna device having the above configuration is configured to use a spacer and a screw when the antenna element is assembled to the substrate as described above, the assembly operation of the antenna element becomes complicated.

  An object of the present invention is to obtain an antenna device in which an antenna element can be easily assembled in consideration of the above facts.

  In order to solve the above-described problem, an antenna device according to the first aspect of the present invention includes a first cover member, a second cover member assembled to the first cover member and having an element support portion, and a plate shape. An antenna element that is formed and supported by the element support portion by engaging with the element support portion of the second cover member, and the first cover member that is spaced apart from the antenna element in the plate thickness direction And a board that is electromagnetically coupled to the antenna element.

  In the antenna device according to claim 1, the substrate assembled to the first cover member is in a plate thickness direction with respect to the antenna element supported by the element support portion of the second cover member assembled to the first cover member. The antenna element and the substrate are electromagnetically coupled when the radio wave is transmitted and received. Here, when the antenna element is assembled to the second cover member, the antenna element is supported by the element support portion (second cover member) if the antenna element is engaged with the element support portion of the second cover member. . Therefore, assembly of the antenna element is easy.

  An antenna device according to a second aspect of the invention is characterized in that in the antenna device according to the first aspect, there is provided a distance constant means for making a distance between the antenna element and the substrate constant.

  In the antenna device according to the second aspect, since the distance between the antenna element and the substrate is made constant by the distance fixing means, the antenna characteristics can be stabilized.

  An antenna device according to a third aspect of the present invention is the antenna device according to the first or second aspect, wherein a through-hole penetrating in the plate thickness direction is provided in a central portion of the antenna element, and the element The support portion includes an insertion shaft to be inserted into the through hole, and a groove into which a part of the antenna element is inserted by rotating the antenna element around the insertion shaft. And an engaging portion for restricting movement in the axial direction with respect to.

  In the antenna device according to the third aspect, when the insertion shaft of the second cover member is inserted into the through hole of the antenna element, movement of the antenna element in the radial direction with respect to the insertion shaft is limited. Then, when the antenna element is rotated around the insertion axis and a part of the antenna element is inserted into the groove provided in the engaging portion of the second cover member, the axial movement of the antenna element with respect to the insertion axis is limited. The Thereby, the antenna element is supported by the second cover member.

  The antenna device according to a fourth aspect of the present invention is the antenna device according to the third aspect, wherein the distance fixing means is the insertion shaft, and a tip of the insertion shaft is in contact with the substrate. It is said.

  In the antenna device according to claim 4, the distal end of the insertion shaft of the second cover member abuts on the substrate assembled to the first cover member, so that the distance between the antenna element and the substrate is made constant. .

  An antenna device according to a fifth aspect of the present invention is the antenna device according to the third or fourth aspect, wherein the antenna element is engaged in the groove of the engagement portion, and the antenna element A rotation restricting portion for restricting rotation around the insertion shaft is provided.

  In the antenna device according to claim 5, when a part of the antenna element is inserted into the groove of the engaging portion of the second cover member, the rotation limiting portion provided in the groove engages with the antenna element. Limit the rotation of the antenna element around the insertion axis. Therefore, it can suppress that a part of antenna element pulls out from the groove | channel of an engaging part.

  The antenna device according to claim 6 is the antenna device according to any one of claims 3 to 5, wherein the insertion shaft is formed in a stepped shape, and the antenna element is formed of the through hole. The hole edge portion is positioned along the axial direction of the insertion shaft with respect to the groove of the engagement portion by contacting the step portion of the insertion shaft.

  In the antenna device according to claim 6, when the hole edge portion of the through hole of the antenna element is brought into contact with the step portion of the insertion shaft, the antenna element and the groove of the engagement portion extend along the axial direction of the insertion shaft. Positioned. Therefore, a part of the antenna element can be easily inserted into the groove of the engaging portion.

  As described above, in the antenna device according to the present invention, the antenna element can be easily assembled.

<First Embodiment>
An antenna device 10 according to a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the antenna device 10 has an antenna cover 14 attached to the inside of a windshield 12 of a vehicle. The antenna cover 14 is disposed on the upper side of the stay 18 for attaching the inner mirror 16 of the vehicle to the windshield 12, and is adjacent to the attachment 20 that covers the base end portion of the stay 18 without a gap.

  As shown in FIGS. 2 to 4, the antenna cover 14 includes a first cover member 22 and a second cover member 24. The first cover member 22 has a pair of side walls 22A that face each other, and a connecting wall 22B that connects base ends of the pair of side walls 22A (ends on the arrow A side in FIGS. 2 to 4). ing. The second cover member 24 is formed in a substantially rectangular plate shape, and is inserted and disposed between the respective front end portions (end portions on the arrow B side in FIGS. 2 to 4) of the pair of side walls 22A. . A plurality of (in the first embodiment, respectively) projecting toward the connecting wall 22B at both ends in the width direction of the second cover member 24 (ends on the arrow C side and arrow D side in FIGS. 2 to 4). (Every two) plate-like locking portions 26 are provided, and locking holes 28 are formed in the central portions of the plurality of locking portions 26, respectively. Engagement projections 30 formed on the front ends of the pair of side walls 22A are fitted into these engagement holes 28, whereby the second cover member 24 is assembled to the first cover member 22. Yes. In addition, the 2nd cover member 24 is attached to the attachment 20 mentioned above, and, thereby, this antenna apparatus 10 is attached to the vehicle.

  An insertion shaft 32 that protrudes toward the connecting wall 22 </ b> B of the first cover member 22 is provided at the center of the second cover member 24. The insertion shaft 32 is formed in a stepped shape, with the proximal end side being a large diameter portion 32A and the distal end side being a small diameter portion 32B. In addition, the second cover member 24 is provided with a pair of engaging portions 34 that protrude toward the connecting wall 22B side on the radially outer side of the insertion shaft 32. The pair of engaging portions 34 is formed in a columnar shape that is concentric with the insertion shaft 32 and is disposed at a substantially point-symmetrical position via the insertion shaft 32. A groove 34 </ b> A that is cut toward one side in the circumferential direction of the insertion shaft 32 (arrow E direction side in FIGS. 2 and 3) is formed in the intermediate portion in the axial direction of the pair of engaging portions 34. The pair of engaging portions 34 and the aforementioned insertion shaft 32 correspond to an antenna element 36 that is a circularly polarized antenna.

  The antenna element 36 is formed in a rectangular plate shape, and the thickness dimension thereof is slightly smaller than the groove width of each groove 34A of the pair of engaging portions 34. Of the four corners of the antenna element 36, the two corners arranged at point-symmetric positions via the center of the antenna element 36 are chamfered. A through hole 38 penetrating in the thickness direction is formed at the center of the antenna element 36. The inner diameter of the through hole 38 is slightly larger than the outer diameter of the small diameter portion 32B of the insertion shaft 32 and smaller than the outer diameter of the large diameter portion 32B. The antenna element 36 has a pair of engaging portion insertion holes 40 that are curved in an arc shape. The pair of engaging portion insertion holes 40 are arranged at point-symmetrical positions through the through holes 38 and correspond to the pair of engaging portions 34. Furthermore, a rotation limiting hole 42 is formed on one side of the pair of engaging portion insertion holes 40 (the arrow F side in FIGS. 2 and 3).

  Here, when the antenna element 36 is assembled to the second cover member 24, the small-diameter portion 32B of the insertion shaft 32 is inserted into the through hole 38, and the pair of engaging portions 34 are inserted into the pair of engaging portions. It is inserted into the hole 40 (see FIG. 5). Thereby, the movement of the antenna element 36 in the radial direction with respect to the insertion shaft 32 is limited. As shown in FIG. 4, when the hole edge portion of the through hole 38 abuts on a step portion 32C formed between the small diameter portion 32B and the large diameter portion 32A, the axis line of the antenna element 36 relative to the insertion shaft 32 is obtained. Relative movement in one direction (arrow B side in FIG. 4) is restricted. In this state, the antenna element 36 and the groove 34 </ b> A of the engaging portion 34 are positioned along the axial direction of the insertion shaft 32, and the antenna element 36 is inserted with respect to the second cover member 24. By being relatively rotated around one side (arrow E side in FIG. 5), each hole edge of the pair of engaging portion insertion holes 40 is inserted into each groove 34A of the pair of engaging portions 34 (FIG. 6). And FIG. 7). As a result, relative movement of the antenna element 36 to both sides in the axial direction with respect to the insertion shaft 32 (arrow A side and arrow B side in FIGS. 2 to 4) is restricted, and the antenna element 36 is supported by the second cover member 24. . Moreover, as shown in FIG. 8, when the hole edge portions of the pair of engaging portion insertion holes 40 are inserted into the grooves 34 </ b> A of the pair of engaging portions 34, they are provided in these grooves 34 </ b> A. The rotation restricting protrusion 34B (rotation restricting portion) is fitted into the rotation restricting hole 42 of the antenna element 36, and the relative rotation (extraction from each groove 34A) of the antenna element 36 with respect to the insertion shaft 32 is restricted. Yes.

  On the other hand, on the opposite side of the second cover member 24 via the antenna element 36, a printed circuit board is formed in a rectangular plate shape between the pair of side walls 22 </ b> A of the first cover member 22 and serves as a power feeding element to the antenna element 36. 44 is arranged. The printed circuit board 44 is fixed to the first cover member 22 in contact with a plurality of ribs 46 formed inside the pair of side walls 22A, and is separated from the antenna element 36 in the thickness direction. And they are arranged in parallel. In addition, as shown in FIG. 4, the tip of the insertion shaft 32 (small diameter portion 32 </ b> B) is in contact with the central portion of the printed circuit board 44, and the distance L between the antenna element 36 and the printed circuit board 44 is small. The configuration is maintained constant. Note that a fastening member such as a screw is used to fix the printed circuit board 44 to the first cover member 22.

  As shown in FIG. 2, a printed wiring 48 made of a conductor such as copper foil is formed on a part of the outer peripheral side on the surface of the printed board 44 on the antenna element 36 side. A ground 50 made of a conductor such as copper foil is formed on the entire surface of the printed circuit board 44 opposite to the antenna element 36 except for the outer peripheral portion.

  One end of a coaxial cable 52 for high-frequency signal transmission is connected to the printed board 44. The outer conductor of the coaxial cable 52 is electrically connected to the ground 50 by, for example, soldering. The central conductor of the coaxial cable 52 passes through the printed circuit board 44 so as not to be electrically connected to the ground 50, and the tip of the central conductor is electrically connected to the printed wiring 48 by soldering, for example. Yes.

  The other end of the coaxial cable 52 is electrically connected to an automatic toll collection system (hereinafter referred to as an ETC device) (not shown) mounted on the vehicle. This ETC device is for automatically paying tolls on toll roads by wireless communication, and this antenna device 10 is an antenna device of this ETC device. That is, the present antenna device 10 is configured to transmit and receive fee settlement information by radio waves to and from a transmission and reception antenna installed at a toll booth or the like on a toll road. At least one of electric power and signals is transmitted between the element 36 and the printed wiring 48 of the printed circuit board 44 by electromagnetic coupling (electromagnetic field mutual induction).

  Next, the operation of the first embodiment will be described.

  In the antenna device 10 having the above configuration, the first cover member 22 is assembled to the second cover member 24. Further, the printed circuit board 44 assembled to the first cover member 22 is separated from the antenna element 36 assembled to the second cover member 24 in the plate thickness direction. The printed wiring 48 and the antenna element 36 are electromagnetically coupled.

  Here, in the antenna device 10, when the antenna element 36 is assembled to the second cover member 24, the insertion shaft 32 (small diameter portion 32 </ b> B) is inserted into the through hole 38, and the pair of engaging portions 34 are paired with each other. It is inserted into the engaging portion insertion hole 40. Thereby, the movement of the antenna element 36 in the radial direction with respect to the insertion shaft 32 is limited. When the antenna element 36 is relatively rotated around the insertion shaft 32 with respect to the second cover member 24 with the stepped portion 32C of the insertion shaft 32 in contact with the hole edge of the through hole 38, a pair of engagements The hole edge portion of the portion insertion hole 40 is inserted into each groove 34A of the pair of engaging portions 34, and the axial movement of the antenna element 36 relative to the insertion shaft 32 is restricted. Thereby, the antenna element 36 is supported by the second cover member 24. Therefore, it is not necessary to use screws, spacers, or the like when assembling the antenna element 36 to the second cover member, and the antenna element 36 can be easily assembled.

  Moreover, in this antenna device 10, the hole edge portion of the through hole 38 of the antenna element abuts on the step portion 32C of the insertion shaft 32, so that the antenna element 36 and each groove 34A of the pair of engaging portions 34 are inserted into the insertion shaft. It is the structure positioned in 32 axial directions. Accordingly, the hole edge portions of the pair of engaging portion insertion holes 40 can be easily inserted into the respective grooves 34A of the pair of engaging portions 34, and the assembly of the antenna element 36 to the second cover member 24 is also performed thereby. Becomes easier.

  Further, in the antenna device 10, when the hole edge portions of the pair of engaging portion insertion holes 40 are inserted into the grooves 34A of the pair of engaging portions 34, the rotation provided in the grooves 34A. The limiting protrusion 34B is fitted in the rotation limiting hole 42 of the antenna element 36, and the relative rotation of the antenna element 36 with respect to the insertion shaft 32 is limited. Therefore, it can suppress that each hole edge part of a pair of engaging part insertion hole 40 slips out from each groove | channel 34A of a pair of engaging part 34, and can suppress that the antenna element 36 falls from the 2nd cover member 24. FIG. .

  Further, in the antenna device 10, the distance L between the antenna element 36 and the printed circuit board 44 is achieved by the front end of the insertion shaft 32 (small diameter portion 32 </ b> B) of the second cover member 24 being in contact with the center of the printed circuit board 44. Is kept constant. Therefore, antenna characteristics can be stabilized.

  In the first embodiment, the pair of engaging portions 34 of the second cover member 24 are inserted into the pair of engaging portion insertion holes 40 of the antenna element 36. Although the hole edge portions are configured to be inserted into the respective grooves 34A of the pair of engaging portions 34, the present invention is not limited to this, and the pair of engaging portions 34 are disposed outside the outer periphery of the antenna element 36, and It is good also as a structure by which an outer peripheral part is inserted in each groove | channel 34A of a pair of engaging part 34. FIG. In this case, the pair of engaging portion insertion holes 40 can be omitted.

  In the first embodiment, when a part of the antenna element 36 (the hole edge portion of the pair of engaging portion insertion holes 40) is inserted into the grooves 34A of the pair of engaging portions 34, each groove Although the rotation restricting projection 34B provided in 34A is configured to fit into the rotation restricting hole 42 of the antenna element 36, the present invention is not limited to this, and a so-called crushing rib is provided in place of the rotation restricting projection 34B. The crushing rib may be crushed when a part of the crushing rib is inserted into the groove 34. In this case, the rotation limiting hole 42 can be omitted.

Furthermore, in the first embodiment, the distance between the antenna element 36 and the printed board 44 is made constant by the tip of the insertion shaft 32 (distance constant means) coming into contact with the printed board 44. However, the present invention is not limited to this, and the distance between the antenna element 36 and the printed circuit board 44 is constant because the protrusion (distance constant means) provided on the second cover member 24 contacts the printed circuit board 44. The distance between the antenna element 36 and the printed circuit board 44 is made constant by a protrusion (distance constant means) attached to the printed circuit board 44 coming into contact with the antenna element 36. It is good also as a structure. Moreover, when each component is shape | molded with high precision, you may abbreviate | omit a distance fixed means.
<Second Embodiment>
Next, a second embodiment of the present invention will be described. Note that the same reference numerals as those in the first embodiment are assigned to the configurations and operations basically similar to those in the first embodiment, and description thereof is omitted.

  FIG. 9 shows a second embodiment of the present invention. This embodiment has basically the same configuration as that of the first embodiment. In this embodiment, the antenna element 36 has a pair of engaging portion insertion holes according to the first embodiment. Instead of 40, a pair of rectangular locking claw insertion holes 60 are provided. The second cover member 24 has a pair of locking claws 62 (element support) inserted into the pair of locking claw insertion holes 60 instead of the pair of engaging portions 34 according to the first embodiment. Part). The pair of latching claws 62 have flexibility, and when inserted into the pair of latching claw insertion holes 60, the inclined surfaces on the distal end side are the respective edge portions of the pair of latching claw insertion holes 60. By interfering with each other, it bends away from each other. When the hole edge portion of the through hole 38 of the antenna element 36 abuts on the step portion 32C of the insertion shaft 32, the claw portion 62A provided on the distal end side of the pair of locking claws 62 becomes a pair of locking claw insertion holes. The antenna element 36 is engaged with the second cover member 24 by being hooked on the edge of the hole 60.

  This embodiment also has basically the same operational effects as the first embodiment. In addition, if it is set as the structure which the nail | claw part 62A of a pair of latching claw 62 catches on the outer peripheral part of the antenna element 36, a pair of latching claw insertion hole 60 is omissible.

It is sectional drawing which shows the structure of the inner mirror periphery of the vehicle with which the antenna device which concerns on the 1st Embodiment of this invention was attached. 1 is an exploded perspective view showing a configuration of an antenna device according to a first embodiment of the present invention. 1 is an exploded perspective view showing a configuration of an antenna device according to a first embodiment of the present invention. It is a side view which shows the structure of the antenna apparatus which concerns on the 1st Embodiment of this invention. It is a top view which shows the structure before the antenna element and 2nd cover member of the antenna apparatus which concern on the 1st Embodiment of this invention are inserted, and a part of antenna element is inserted in the groove | channel of an engaging part. . It is a top view which shows the structure of the antenna element and 2nd cover member of the antenna apparatus which concern on the 1st Embodiment of this invention, and shows the state in which a part of antenna element was inserted in the groove | channel of the engaging part. It is a perspective view which shows the structure of the antenna element and 2nd cover member of the antenna apparatus which concern on the 1st Embodiment of this invention, and shows the state in which a part of antenna element was inserted in the groove | channel of the engaging part. It is sectional drawing which shows the partial structure of the engaging part of the antenna element and 2nd cover member of the antenna apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Antenna apparatus 22 1st cover member 24 2nd cover member 32 Insertion axis (distance constant means)
32C Step part 34 Engagement part (element support part)
34A Groove 34B Rotation limiting protrusion (Rotation limiting part)
36 Antenna element 38 Through hole 44 Substrate

Claims (6)

A first cover member;
A second cover member assembled to the first cover member and having an element support;
An antenna element formed in a plate shape and supported by the element support portion by engaging with the element support portion of the second cover member;
A substrate that is assembled to the first cover member in a state of being separated from the antenna element in the thickness direction, and is electromagnetically coupled to the antenna element;
An antenna device.   The antenna apparatus according to claim 1, further comprising a distance constant unit that constants a distance between the antenna element and the substrate.   A through-hole penetrating in the plate thickness direction is provided in the central portion of the antenna element, and the element support portion has an insertion shaft inserted into the through-hole, and the antenna element is rotated around the insertion shaft. 3. An engagement portion that has a groove into which a part of the antenna element is inserted and restricts movement of the antenna element in the axial direction with respect to the insertion axis. The antenna device described.   The antenna apparatus according to claim 3, wherein the distance fixing unit is the insertion shaft, and a tip of the insertion shaft is in contact with the substrate.   The rotation restriction part which engages with the antenna element and restricts the rotation of the antenna element around the insertion axis is provided in the groove of the engagement part. The antenna device according to 1.   The insertion shaft is formed in a stepped shape, and the antenna element has an axis line of the insertion shaft with respect to the groove of the engagement portion by a hole edge portion of the through hole coming into contact with the step portion of the insertion shaft. 6. The antenna device according to claim 3, wherein the antenna device is positioned along a direction.

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