JP4036671B2 - Vehicle antenna - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular antenna provided in an exterior product made of a hollow body such as a vehicular air spoiler or a vehicular bumper.
[0002]
[Prior art]
Conventionally, vehicles are equipped with a receiving antenna such as a radio. In addition, by providing such an antenna in an exterior product made of a resin hollow body such as a vehicle air spoiler or a vehicle bumper, the space is shared and the appearance of the entire vehicle is improved. Known (for example, see Japanese Patent Application Laid-Open Nos. 9-142338 and 2001-102826).
[0003]
10 and 11 show an example of a vehicle antenna disclosed in Japanese Patent Laid-Open No. 2001-102826.
[0004]
FIG. 10 is a cross-sectional view of the main parts of the vehicle body and the vehicle air spoiler, and FIG. 11 is an explanatory view of a specific arrangement example of the antenna elements.
[0005]
In FIG. 10, a hollow air spoiler 101 having a vertically aligned structure is fixed above the rear part of the vehicle body 100. In addition, as shown in FIG. 11, an antenna 108 in which a plurality of film-like antenna elements 102 to 107 corresponding to a reception target medium are arranged is provided inside the air spoiler 101.
[0006]
The antenna elements 102 to 107 of the antenna 108 are attached to the inner upper surface of the air spoiler 101 with an adhesive or the like. This is because radio waves normally reach from above the vehicle body 100 and are preferably arranged above the air spoiler 101.
[0007]
The first feeder 110 connected to the antenna 108 via the power feeding unit 109 includes a through hole 101a formed in the air spoiler 101, a through hole 111a formed in the outer panel 111 constituting the vehicle body 100, and the vehicle body 100. Each of them penetrates 112a formed in the inner panel 112 to be configured and is led into the vehicle interior. A ground wire 110 a for grounding the vehicle body 100 extends from a part of the first feeder 110, and the tip of the ground wire 110 a is fixed to the inner panel 112 with a screw 113.
[0008]
Each antenna element 102 to 107 of the antenna 108 is made of a conductive pattern formed on a base film, and its dimensional shape and arrangement condition are set in relation to the frequency of the reception target medium.
[0009]
In this example, the antenna element 102 is for UHF, the antenna element 103 is for FM and VHF, the antenna element 104 is for AM, the antenna element 105 is for FM and VHF, the antenna element 106 is for UHF, and the antenna element 107 is for GPS. It is used.
[0010]
Here, the antenna element 107 for GPS has an independent configuration because the reception frequency band is significantly different from the other antenna elements 102 to 106.
[0011]
Each of these antenna elements 102 to 107 is formed on the base film 114 in a shape and arrangement relationship as shown in the drawing.
[0012]
In general, it is difficult to satisfactorily receive radio waves in a wide frequency band (a plurality of frequency bands) with one antenna element, while the shape of the antenna element can be made smaller as the frequency band to be received is higher. .
[0013]
Therefore, the antenna elements 102 and 106 are formed small for the UHF band. The antenna elements 103 and 105 are formed in a medium size for the VHF band. Further, the antenna element 104 is formed in a large size for the AM band. Further, the antenna element 107 is formed small for the GPS band.
[0014]
In addition, although all the antenna elements 102 to 107 are arranged inside the air spoiler 101, the antenna elements 102 and 106 in the high frequency band (UHF band for TV broadcasting) are divided in particular, and the divided antenna elements 102 and An effective diversity effect can be obtained by arranging 106 in a state of being separated from both ends.
[0015]
In other words, generally, when the frequency of a radio wave increases (the wavelength decreases), the interference caused by the direct wave and the reflected wave changes at a short distance. This becomes a problem when receiving a moving object such as an automobile. Conventionally, there is diversity reception as a countermeasure against this by selecting and switching the best antenna by utilizing the fact that the reception state changes depending on the position of the antenna with a plurality of antennas.
[0016]
Further, it is ideal if the same reception sensitivity can be obtained from all 360 ° directions with a single antenna (non-directionality), but there is actually a direction in which reception sensitivity decreases (directivity). This directivity may be caused by a problem with the antenna itself or by interference with the vehicle body. The diversity reception described above is effective as a measure against directivity, but in order to obtain a sufficient effect, it is necessary that the plurality of antennas have a sufficiently distant relationship.
[0017]
Multipath and directivity disturbances become more noticeable as the frequency increases. That is, it occurs slightly in FM broadcasting and slightly occurs in the VHF band of TV broadcasting. Moreover, it frequently occurs in the UHF band of TV broadcasting. That is, among these frequency bands, diversity reception is most necessary in the case of the UHF band for TV broadcasting, and for this purpose, a plurality of antennas must be spaced apart sufficiently.
[0018]
Therefore, in this example, when the antenna elements 102 to 107 are arranged in a narrow space in the air spoiler 101, as described above, the antenna elements 102 and 106 in the UHF band of TV broadcasting that most require diversity reception are used as the air spoiler. 101 is configured so as to obtain a diversity effect appropriately by being spaced from both ends.
[0019]
[Problems to be solved by the invention]
By the way, in the vehicular antenna configured as described above, the ground wire 110a is provided separately from the first feeder 110 for signal lines.
[0020]
However, if the ground wire 110a uses wiring different from the feeder 110, there is a problem that connection with many feeders 110 is troublesome.
[0021]
In addition, the ground wire 110a branches from the first feeder 110 penetrating all of the through hole 101a formed in the air spoiler 101, the through hole 111a formed in the outer panel 111, and the 112a formed in the inner panel 112. After being routed as described above, it is fixed to the inner panel 112 by screws 113 as a ground to the vehicle body 100. Therefore, the wiring operation is troublesome and requires fixing work both inside and outside the vehicle body. There has been a problem that the grounding work becomes complicated.
[0022]
In order to solve the above problem, the present invention provides a vehicle antenna that can easily perform grounding work without adversely affecting antenna performance when grounding an antenna disposed in a hollow body. Objective.
[0023]
[Means for Solving the Problems]
In order to achieve the object, the vehicle antenna according to the present invention includes a first antenna element made of a substantially rigid body disposed in a vehicle air spoiler made of a hollow body, and a flexible AV line. A second antenna element that is disposed closer to the vehicle body side than the first antenna element in the vehicle air spoiler, and one end of which is electrically connected to the first antenna element; and a second antenna element disposed in the vehicle air spoiler. is, one end of the core wire to the other end of the antenna element of the second are connected, the coaxial cable connector is connected to the other end, near the connection portion between the second antenna element and the core wire of the coaxial cable a holder shield wire of the coaxial cable is electrically connected, the holder is attached to a surface in contact with the body of the air spoiler the vehicle And an opening has been made, the shield wire to the vehicle body through the opening and electrically connected, characterized in that was grounded.
[0024]
According to such a configuration, disposed substantially in the first antenna element is air in the spoiler for a vehicle comprising a hollow body made of a rigid, one end of the second antenna element that consists by AV line with a flexible Is electrically connected to the first antenna element, the core wire of the coaxial cable is connected to the other end of the second antenna element, and the shield of the coaxial cable is near the connection portion between the second antenna element and the core wire of the coaxial cable. A holder to which the wire is electrically connected and an opening to which the holder is attached are formed on a surface of the vehicle air spoiler that is in contact with the vehicle body, and the shield wire is electrically connected to the vehicle body through the opening to be grounded. .
[0025]
The vehicle antenna of the present invention is characterized in that the shield wire is provided in the opening and is electrically connected to a bolt for fixing the vehicle air spoiler to a vehicle body.
[0026]
Further, in the vehicle antenna of the present invention, the bolt is provided integrally with a conductive metal bracket that reinforces the periphery of the opening, and the shield wire is electrically connected to the bolt via the bracket. It is connected.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a vehicle antenna according to the present invention is applied to an antenna installed in an air spoiler equipped at the rear of a vehicle as a hollow body, and will be described with reference to FIGS.
[0028]
In FIG. 9, reference numeral 1 denotes a vehicle body, and 2 denotes a hollow air spoiler fixed to the upper rear portion of the vehicle body 1.
[0029]
As shown in FIG. 8, the air spoiler 2 is formed with first, second, third, and fourth windows 2a, 2b, 2c, and 2d that open to the bottom surface. A plurality of fixtures 3 such as screws and clips for mounting the vehicle body are provided on the bottom surface of the air spoiler 2. Further, the air spoiler 2 includes an antenna element 4 for receiving radio waves, a retainer 5 holding the antenna element 4, a bracket 6 for fixing the retainer 5 to the air spoiler 2, and one end of the antenna element 4. And a connector 8 to which the other end of the cable 7 is connected.
[0030]
The connector 8 can also be connected by inserting a power source or a signal line (not shown) of the high mount stop lamp SL mounted on the air spoiler 2 from the second window 2b. By sharing the connector 8 and the second window 2b, it is not necessary to provide a dedicated connector or window for the high mount stop lamp SL.
[0031]
FIG. 8 is a bottom view of a portion located on the right side of the vehicle body from the vicinity of the center of the vehicle body when the air spoiler 2 is attached to the vehicle body, but is located on the left side of the vehicle body from the vicinity of the center of the vehicle body when attached to the vehicle body. The parts are basically mirror-symmetric with the exception of the cable 9 connected to the connector 8.
[0032]
Further, as shown in FIG. 7A, the antenna element 4 and the retainer 5 are subjected to vibration-resistant absorption processing by being sandwiched between the cushions 10 in a superimposed state. Furthermore, as shown in FIG. 7B, a bracket 11 made of a conductive metal material is provided by insert molding at the opening edge of the third window 2c, thereby forming the third window 2c. As a result, the strength reduction of the air spoiler 2 is reinforced.
[0033]
The antenna element 4 is formed of, for example, brass tin plating or reflow tin plating, and one end of the antenna element 4 is connected to one end of the cable 7 (the same applies to the cable 9) as shown in FIG. Is provided. Further, bendable tongue pieces 4b are raised at appropriate plural positions of the antenna element 4. Further, the antenna element 4 is a strip-shaped monopole antenna in which the width on the other end side is gradually narrowed compared to the one end side on which the protrusion 4a is provided.
[0034]
Specifically, in the present embodiment, as shown in FIG. 3, the total length a from one end to the other end of the antenna element 4 is 345 mm, the length b from one end to the tapered start end is 295 mm, one end C is 210 mm, the width d of the bent portion from one end is 25 mm, the maximum width e is 30 mm, the width f including the bent portion is 60 mm, and the width g on the other end side from the step portion is 20 mm. As described above, the same antenna element 4 is used on both the left and right sides, thereby forming diversity.
[0035]
And by using such an antenna element 4, as shown in FIG. 5, two frequency bands for VHF (90 to 220 MHz) and UHF (470 to 770 MHz) can be satisfactorily received. Note that reception is possible even in the FM band (70 to 90 MHz) adjacent to the frequency band for VHF.
[0036]
By the way, in the above embodiment, the antenna element 4 having a two-stage and tapered shape has been disclosed. However, the antenna element 4 may have three or more stages, or may have two stages excluding the taper.
[0037]
The retainer 5 is made of, for example, ABS resin. Further, the retainer 5 is provided with a plurality of notched or hole-like engaged portions 5a. The tongue 4b of the antenna element 4 is positioned on the engaged portion 5a and folded, whereby the antenna element 4 is folded. And the retainer 5 are coupled in a superposed state. A screw hole 5b for fixing the bracket 6 is formed at one end of the retainer 5, and a screw (not shown) is inserted in a state where the screw hole 5b and the screw hole 6a of the bracket 6 are aligned. By doing so, the bracket 6 is fixed to the retainer 5.
[0038]
The cable 7 includes an AV line 13 provided with a ring-shaped connection terminal 12 that engages with the protrusion 4 a at one end, a coaxial cable 15 provided with a connector 14 connected to the connector 8 at one end, and coaxial with the AV line 13. A connection member 16 that connects the other ends of the cable 15 is provided.
[0039]
Similarly, the cable 9 includes an AV line 13 ′, a connector (not shown), a coaxial cable 15 ′, and a connection member 16 that is the same as the cable 7.
[0040]
Note that the length of the AV line 13 having a function as an antenna element and having flexibility is 120 mm in this embodiment (the length of the AV line 13 ′ of the other cable 9 is 140 mm). When the antenna element 4 needs to be adjusted at the design stage due to the arrangement relationship of the element 4 on the left and right of the vehicle body, the length of the AV line 13 (and the AV line 13 'of the other cable 9) is simply changed. Adjustment is possible. Further, the adjustment due to the installation height or the like accompanying the difference in the vehicle type can also be adjusted by changing the length of the AV line 13.
[0041]
As shown in FIGS. 1 to 3, the connection member 16 includes a heat-shrinkable tube 17 that straddles the connection end of the AV wire 13 and the coaxial cable 15, and a holder 18 that holds the vicinity of the center of the tube 17. Yes.
[0042]
As shown in FIG. 1B, the AV line 13 includes a jacket 13a and a core wire 13b. The coaxial cable 15 includes an outer sheath 15a, a mesh-like shield wire 15b exposed by removing the outer sheath 15a, an insulator 15c exposed by removing the shield wire 15b, and an insulator 15c. The core wire 15d is provided.
[0043]
The tube 17 is formed from a heat-shrinkable material. Further, an adhesive layer (not shown) is provided on the inner surface of the tube 17. This adhesive layer is formed in a cylindrical shape from a material that hardens after heat melting and is positioned on the inner surface of the tube 17. However, the adhesive layer is not particularly limited to this.
[0044]
The holder 18 has a tongue-like holding leg 18a that holds the AV wire 13 by fitting from the outside of the tube 17, and a tongue-like holding leg 18b that holds the coaxial cable 15 by fitting from the outside of the tube 17. A gap 18c, 18d exists between the holding legs 18a, 18b, and a pair of sandwiching pieces 18e, 18f sandwiching the vicinity of the opening edge of the third window 2c, and the base side of one sandwiching piece 18e are provided. A holding portion 18g and a fixing hole 18h that is provided on one clamping piece 18e and is fixed to the bracket 11 via a bolt 19 (see FIG. 7B) are provided.
[0045]
The bracket 11 is made of a conductive metal material having a relatively high strength (strength adjustment by material or thickness), and the third window 2c is formed in cooperation with the air spoiler 2 as shown in FIG. When the air spoiler 2 is molded, insert molding is performed. Further, the bracket 11 is provided with a vehicle body fixing bolt 20, and is thereby grounded to the vehicle body 1 via the shield wire 15 b, the holder 18, the bracket 11, and the bolt 20.
[0046]
Therefore, the bracket 11 has a function of reinforcing the third window 2c, and can also have a function of a fixing member for the holder 18 and a function of a grounding member, and in particular, a dedicated member for grounding needs to be provided. Also disappear. Since only the cable having a lower impedance than the cable 7 is interposed between the shield wire 15 b and the vehicle body 1, the shield wire 15 b is substantially grounded in a directly connected state to the vehicle body 1. This also prevents the ground portion of the shield wire 15b from adversely affecting the antenna performance of the entire element including the antenna element 4 and the AV line 13 as the second element.
[0047]
In the above configuration, the air spoiler 2 is formed as a hollow product with the windows 2a, 2b, 2c and 2d being opened and the bracket 11 and the like being inserted.
[0048]
On the other hand, the antenna unit is configured by mounting the bracket 6 and the cushion 10 in a state where the antenna element 4 and the retainer 5 are overlapped.
[0049]
On the other hand, a ring-shaped connection terminal 12 is provided at one end of the AV line 13 and a connector 14 is provided at one end of the coaxial cable 15 (or later), and the tube 17 provided with an adhesive layer on the inner surface is connected to the AV line 13 or the coaxial cable. The core wires 13b and 15d are soldered in advance by being inserted into one of the wires 15.
[0050]
At this time, it is assumed that the coaxial cable 15 removes the outer sheath 15a to expose the shield wire 15b, twists the shield wire 15b, removes the tip of the insulator 15c, and exposes the core wire 15d.
[0051]
Furthermore, after the portion where the shield wire 15b is twisted is exposed from the hole 17a provided in the tube 17, the tube 17 is thermally contracted, and at the same time, the adhesive layer is melted and then cured.
[0052]
Thereafter, the tube 17 is positioned between the holders 18 and the holding legs 18a and 18b are fitted, whereby the AV line 13 and the coaxial cable 15 are held by the holder 18, and the end portion of the shield wire 15b twisted is AV. The cable 7 is configured by being held by the holding portion 18g by being tilted to the line 13 side.
[0053]
At this time, since the tube 17 and the AV line 13 and the tube 17 and the coaxial cable 15 are bonded to each other by the adhesive layer, no gap is generated, and even if the holding legs 18a and 18b are fitted, the gap is not generated. Occurrence is prevented and hermeticity with the outside is maintained. Moreover, the hole 17a is rich in elasticity, and even if the shield wire 15b is inserted into the hole 17a, no gap is generated between the shield wire 15b and the hole 17a.
[0054]
The cable 7 can be attached to the antenna unit by fitting the cable 7 with the connection terminal 12 inserted into the protrusion 4a.
[0055]
In order to mount the antenna unit with the cable 7 in the air spoiler 2, the cable 7 side is inserted from the first window 2a as the starting end (the wire rod is guided from the second window 2b to the first window 2a side). The tip may be connected to the cable 7 or the like and pulled in.)
[0056]
Next, after the holder 18 is mounted and fixed to the bracket 11 in the third window 2c, the connector 8 and the connector 14 are joined from the second window 2b while being positioned in the fourth window 2d, and the bracket 6 and the like. To fix in the air spoiler 2.
[0057]
In this state, since a part of the antenna element 4 can be seen from the fourth window 2d, the antenna element 4 and the holder 18 that can be seen from the fourth window 2d, and the holder 18 and the second window 2b. A continuity test with the connector 14 can be performed, and it is also possible to confirm a disconnection after assembly.
[0058]
The windows 2a to 2d are preferably closed with tape or the like when the vehicle body is fixed. Further, since the first to third windows 2a to 2c are hidden by the high mount stop lamp SL when the vehicle body is fixed, they cannot be seen from the outside including the tape. Similarly, the fourth window 2d is hidden from view by the vehicle body 1 from the outside.
[0059]
By the way, although the example which mounted | wore the air spoiler 2 with the vehicle antenna was disclosed in the said embodiment, for example, it can apply to the general hollow goods (especially resin molded product), such as a rear bumper RB. Of course.
[0060]
【The invention's effect】
The vehicle antenna of the present invention is configured as described above, so that when grounding the antenna disposed in the hollow body, the grounding work can be easily performed without adversely affecting the antenna performance. Can do.
[Brief description of the drawings]
1A and 1B show a vehicle antenna according to an embodiment of the present invention, in which FIG. 1A is a front view of a joined portion, and FIG. 1B is a front view of the joined portion with a holder removed.
FIG. 2 is a front view of a cable, showing a vehicle antenna according to an embodiment of the present invention.
FIG. 3 shows a vehicular antenna according to an embodiment of the present invention, and is a front view of a main part in which a cable is joined to an element.
FIG. 4 is a perspective view of a main part in a state where a holder is attached to a reinforcing bracket, showing the vehicle antenna according to the embodiment of the present invention.
FIG. 5 is a graph showing reception sensitivity by elements, showing a vehicle antenna according to an embodiment of the present invention.
FIG. 6 is an exploded perspective view of the antenna unit, showing the vehicle antenna according to the embodiment of the present invention.
7A and 7B show a vehicle antenna according to an embodiment of the present invention, in which FIG. 7A is a cross-sectional view of an air spoiler near the main part of the antenna unit, and FIG. It is sectional drawing which abbreviate | omitted the part.
FIG. 8 is a bottom view showing the vehicle antenna according to the embodiment of the present invention, with a part of the air spoiler omitted.
FIG. 9 is a perspective view of a vehicle body in a state where an air spoiler is mounted, showing a vehicle antenna according to an embodiment of the present invention.
FIG. 10 is a cross-sectional view of a main part of a vehicle body and a vehicle air spoiler, showing a conventional vehicle antenna.
FIG. 11 shows a conventional vehicle antenna and is an explanatory diagram of a specific arrangement example of antenna elements.
[Explanation of symbols]
2 Air spoiler (vehicle exterior), 2c 3rd window (opening), 4 Antenna element (first antenna element), 11 Bracket, 13 AV line (2nd antenna element), 15 Coaxial cable, 15b Shield Wire, 15d core wire, 20 volts.

Claims (3)

A first antenna element made of a substantially rigid body disposed in a vehicle air spoiler made of a hollow body;
A second antenna element that is configured by a flexible AV wire, is disposed closer to the vehicle body side than the first antenna element in the vehicle air spoiler, and has one end electrically connected to the first antenna element When,
Disposed in an air spoiler for a vehicle, one end side of the core to the other end of the antenna element of the second is connected, a coaxial cable connector is connected to the other end,
A holder in which a shield wire of the coaxial cable is electrically connected in the vicinity of a connection portion between the second antenna element and the core wire of the coaxial cable ;
The holder is attached, and an opening formed on a surface of the vehicle air spoiler in contact with the vehicle body,
A vehicle antenna, wherein the shield wire is electrically connected to a vehicle body through the opening and grounded. The vehicular antenna according to claim 1, wherein the shield wire is electrically connected to a bolt provided in the opening for fixing the vehicular air spoiler to a vehicle body. The bolt is provided integrally with a conductive metal bracket that reinforces the periphery of the opening, and the shield wire is electrically connected to the bolt via the bracket. Item 3. The vehicle antenna according to Item 2.

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