Abstract:
The purpose of the present invention is to enable a secure attachment of an antenna element and to facilitate adjustment of the antenna element characteristics. Rearward of a spoiler are formed a plurality of lateral grooves extending in a left-right direction of a vehicle, and a plurality of vertical grooves extending in a front-rear direction of the vehicle. The plurality of lateral grooves and the plurality of vertical grooves form latticed grooves as grooves in the shape of a lattice for installing an antenna element. The antenna element is formed by a conductive wire. One end of the antenna element is connected to an amplifier, and the other end is opened. The antenna element extends from the amplifier via a power feeding groove and the right-end one of the vertical grooves to the rear end of the groove, from which the antenna element is fitted in a route along the most rearward one of the lateral grooves to the vicinity of the left-end one of the vertical grooves, thus being securely attached to the spoiler.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is the U.S. national stage of application No. PCT/JP2014/053169, filed on Feb. 12, 2014. Priority under 35 U.S.C. §119(a) and 35 U.S.C. §365(b) is claimed from Japanese Application No. 2013-069661, filed Mar. 28, 2013, the disclosure of which is also incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to vehicle accessories and vehicle-mounted antennas, as well as to structures for attaching an antenna element. 
       BACKGROUND ART  
       [0003]    Spoiler antennas including an antenna element in a spoiler have been widely used as a vehicle-mounted antenna. Spoilers are accessories that are attached to the body of a vehicle, for regulating the flow of air surrounding the vehicle and for giving an aesthetic appearance to the vehicle. Spoilers include visor-shaped spoilers that are attached above the rear window of a vehicle, and wing-shaped spoilers that are attached at the rear of a vehicle. Typically, spoilers are formed by a hollow plastic resin, and an antenna element is attached to the inside of a spoiler. 
         [0004]    Patent Document 1 identified below describes a spoiler antenna serving as a vehicle antenna device. The spoiler antenna is a spoiler that includes an antenna element formed by a conductor. A plurality of fixing components having insertion holes formed therein are disposed at predetermined positions on an inner surface of the spoiler. The antenna element is inserted through the insertion holes of the fixing components, and is fixed to the inside of the spoiler via the fixing components. Patent Document 1 also discloses a spoiler antenna having engagement tabs projecting from an inner wall of the spoiler in place of the fixing components. In this spoiler antenna, the antenna element is held in the engagement tabs, so that the antenna element is fixed to the spoiler. 
         [0005]    Vehicle-mounted antennas further include other antennas such as antennas having an antenna element attached to the inside of a bumper that is formed by a hollow plastic resin, and antennas having an antenna element attached to an overhead console in the cabin. 
       CITATION LIST  
     Patent Literature 
       [0006]    Patent Document 1: JP 2008-85757 A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    In most vehicle-mounted antennas that include an antenna element formed by a conductor, structures for fixing an antenna element at a certain position are formed in an accessory such as a spoiler or a bumper beforehand, and the antenna element is fixed to the accessory in a later step. In a spoiler antenna as disclosed in Patent Document 1, for example, the above-described fixing components or engagement tabs are formed on the spoiler beforehand, and the antenna element is fixed to the spoiler in the process of assembly of the spoiler or attachment of the spoiler to a vehicle. 
         [0008]    Characteristics of an antenna that includes an antenna element formed by a conductor may be adjusted by changing the length, arrangement, or the like of the antenna element. However, it is difficult to adjust characteristics when structures for fixing an antenna element at a certain position are formed in an accessory. Additionally, partial fixing of an antenna element may cause loosening of the antenna element, and may cause noise during driving of the vehicle. 
         [0009]    Objects of the present invention are to securely fix an antenna element, and to easily adjust characteristics of the antenna element. 
       Solution to Problem    
       [0010]    According to one aspect of the present invention, there is provided a vehicle accessory that is attachable to a vehicle, the vehicle accessory comprising a groove on a surface, the groove forming a plurality of paths, wherein a conductor that forms an antenna element is disposed in one of the plurality of paths. 
         [0011]    Further, in the vehicle accessory according to the present invention, it is preferable that the groove comprises a first-direction groove extending in a first direction, and a plurality of second-direction grooves extending in a second direction, the first-direction groove intersecting the plurality of second-direction grooves. 
         [0012]    Further, in the vehicle accessory according to the present invention, it is preferable that the plurality of paths are in a grid pattern. 
         [0013]    Further, it is preferable that the vehicle accessory according to the present invention further comprises a supporting component that is attachable to and detachable from the groove, wherein the conductor is supported by the supporting component. 
         [0014]    Further, it is preferable that the vehicle accessory according to the present invention further comprises a tab that is provided from an edge of an opening of the groove, wherein the conductor disposed in the groove is held by the tab. 
         [0015]    Further, it is preferable that the vehicle accessory according to the present invention further comprises a tube that covers the conductor, wherein a portion of the conductor covered by the tube is held by the tab. 
         [0016]    Further, it is preferable that the vehicle accessory according to the present invention serves as a spoiler that is attachable to a vehicle. 
         [0017]    According to another aspect of the present invention, there is provided a vehicle-mounted antenna comprising the vehicle accessory and the conductor. 
       Advantageous Effects of Invention 
       [0018]    By employing the present invention, it is possible to securely fix an antenna element, and to easily adjust characteristics of the antenna element. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]      FIG. 1  illustrates a vehicle on which a spoiler is mounted. 
           [0020]      FIG. 2  illustrates a spoiler antenna according to an embodiment of the present invention. 
           [0021]      FIG. 3  is an enlarged view of a spoiler antenna. 
           [0022]      FIG. 4  is a cross-sectional view of a grid pattern groove. 
           [0023]      FIG. 5A-5C  illustrates a plurality of different paths in which an antenna element may be disposed. 
           [0024]      FIG. 6  is a cross-sectional view illustrating a structure that allows an antenna element to be fixed to a spoiler. 
           [0025]      FIG. 7  is a perspective view illustrating a structure that allows an antenna element to be fixed to a spoiler. 
           [0026]      FIG. 8  illustrates a structure including tabs that are formed on a groove of a spoiler to fix an antenna element in the groove. 
       
    
    
     DESCRIPTION OF EMBODIMENTS  
       [0027]      FIG. 1  illustrates a vehicle  100 . The vehicle  100  has a visor-shaped spoiler  10  disposed above a rear window  12 . The spoiler  10  is a hollow exterior component made of, for example, a plastic resin, for regulating the flow of air surrounding the vehicle  100  and for giving an aesthetic appearance to the vehicle  100 . 
         [0028]      FIG. 2  illustrates a spoiler antenna  14  according to an embodiment of the present invention. In  FIG. 2 , a cover plate is removed from the spoiler  10 . In other words,  FIG. 2  illustrates a bottom surface of the spoiler  10 . The x-axis points to the front of the vehicle. The y-axis points vertically downward. The z-axis points to the left as viewed facing the front of the vehicle. The spoiler antenna  14  includes an antenna element  16 , the spoiler  10 , an amplifier  18 , and a harness  20 . The spoiler antenna  14  is used for, for example, an AM radio, an FM radio, a DAB (Digital Audio Broadcast) receiver, or a digital television receiver. 
         [0029]    A plurality of row grooves  22  extending in the side-to-side direction of the vehicle and a plurality of column grooves  24  extending in the fore-and-aft direction of the vehicle are formed in a rear portion of the spoiler  10 .  FIG. 2  illustrates an example in which five row grooves  22  and nine column grooves  24  are formed.  FIG. 3  is an enlarged view of a portion of the spoiler  10  near the center. The plurality of row grooves  22  and the plurality of column grooves  24  form a grid pattern groove  26  that is a groove having a grid pattern in which the antenna element  16  is disposed. 
         [0030]    As can be seen in  FIG. 2 , each row groove  22  connects between the leftmost column groove  24  and the rightmost column groove  24 . Seven column grooves  24  are disposed between the right and left ends of the row grooves  22  at predetermined intervals, and intersect with the row grooves  22 . A power supply groove  28  extends from the front end of the rightmost column groove  24  to the location at which the amplifier  18  is disposed. 
         [0031]    The antenna element  16  is formed by a conductor. For example, a strand of a plurality of metal conductor wires or a single-wire metal conductor may be used as the conductor that forms the antenna element  16 . The conductor that forms the antenna element  16  may be coated with an insulator. 
         [0032]    The antenna element  16  has one end connected to the amplifier  18 , and another end left open. The antenna element  16  is fitted into the power supply groove  28  and the grid pattern groove  26 , and is fixed to the spoiler  10 . In the example illustrated in FIG.  2 , the antenna element  16  is fitted into a path extending from the amplifier  18  through the power supply groove  28  and the rightmost column groove  24  to the rear end of the rightmost column groove  24 , and from there along the rearmost row groove  22  to near the leftmost column groove  24 . 
         [0033]      FIG. 4  illustrates a cross-sectional view taken along line A-B of  FIG. 3 . The row grooves  22  are formed in a shape conforming to a surface of the antenna element  16 . For example, when the antenna element  16  has a circular cross section, the row grooves  22  are formed to have an arc-shaped cross section. Although not illustrated in  FIG. 4 , the column grooves are also formed to have a cross-sectional shape conforming to the circumference of the antenna element  16 . 
         [0034]    As illustrated in  FIGS. 3 and 4 , the antenna element  16  is fixed using adhesive tape members  30  affixed at predetermined intervals in the longitudinal direction of the antenna element  16 . In other words, the antenna element  16  is covered by the adhesive tape members  30  and fixed to the spoiler  10  with the antenna element  16  being fitted in the row grooves  22  or the column grooves  24 . 
         [0035]    The grid pattern groove  26  forms a plurality of different paths in which an antenna element  16  may be disposed.  FIGS. 5A to 5C  illustrate a portion of the bottom surface of the spoiler  10  on which the grid pattern groove  26  is formed. The row grooves are denoted by reference numerals A to E sequentially from the front toward the rear. The column grooves are denoted by reference numerals  1  to  9  sequentially from the right toward the left. 
         [0036]    In an example illustrated in  FIG. 5A , an antenna element  16  is disposed in a path passing through the column groove  1 , the row groove E, the column groove  3 , the row groove B, the column groove  4 , the row groove E, the column groove  5 , the row groove A, the column groove  7 , and the row groove C to a junction of the row groove C and the column groove  8 . In an example illustrated in  FIG. 5B , an antenna element  16  is disposed in a path passing through the column groove  1 , the row groove B, the column groove  4 , the row groove D, the column groove  5 , the row groove A, the column groove  7 , and the row groove D to a junction of the row groove D and the column groove  9 . In an example illustrated in  FIG. 5C , an antenna element  16  is disposed in a path passing through the column groove  1 , the row groove A, the column groove  5 , and the row groove E to a point in the row groove E between the column groove  7  and the column groove  8 . The antenna elements  16  disposed in these paths have different shapes or lengths. 
         [0037]    Among a plurality of different paths formed in the grid pattern groove  26 , an antenna element  16  is disposed in a path that provides predetermined characteristics. Specifically, in the process of building a prototype of the spoiler antenna  14 , characteristic adjustment (tuning) is performed in a manner described below. While the antenna element  16  is disposed in different paths, the characteristics of the spoiler antenna  14  are measured each time the path is changed, to determine a path that provides desired characteristics. 
         [0038]    Returning to  FIG. 2 , other components of the spoiler antenna  14  will be described below. The amplifier  18  is fixed on the front side of the power supply groove  28 . One end of the antenna element  16 , which is fitted in the grid pattern groove  26  and the power supply groove  28 , is connected to the amplifier  18 . Further, the harness  20  is connected to the amplifier  18 . The harness  20  is a bundle of a plurality of conductors, such as a signal line for transmitting signals that are received by the antenna element  16  and amplified by the amplifier  18 , and a power supply line for supplying power supply electric power to the amplifier  18 . The harness  20  passes through the inside of the spoiler  10 , and is extended to the outside of the spoiler  10  to reach the inside of the vehicle. The signal line included in the harness  20  is connected to a receiver disposed in the vehicle, and the power supply line included in the harness  20  is connected to a power supply device disposed in the vehicle. 
         [0039]    By employing the above-described structure, the antenna element  16  is fitted into the power supply groove  28  and the grid pattern groove  26 , and is fixed to the spoiler  10 . As a result, a surface of the antenna element  16  is supported by the spoiler  10  over a large area, and the antenna element  16  is securely fixed to the spoiler  10 . Further, a plurality of different paths through which the antenna element  16  may be disposed are formed in the grid pattern groove  26 . As a result, the shape or length of the antenna element  16  can be easily changed, and characteristics can be easily adjusted. 
         [0040]    The groove in which the antenna element  16  is disposed may also be in a pattern other than a grid pattern. For example, a plurality of grooves having freely chosen shapes that are connected to the power supply groove  28  may be provided to thereby form a plurality of different paths through which the antenna element  16  may be disposed. Further, the longitudinal direction of the grooves is not limited to the fore-and-aft direction or the transverse direction of the vehicle, and may be inclined with respect to the fore-and-aft direction of the vehicle. 
         [0041]    As a component for fixing the antenna element in grooves of the spoiler, a supporting component formed from an elastic material may be used.  FIG. 6  illustrates a cross-sectional view of the antenna element  16 , the spoiler  10 , and a supporting component  32 . Further,  FIG. 7  illustrates a perspective view of these components. A groove  34  formed in the spoiler  10  corresponds to one of the above-described row or column grooves. 
         [0042]    The groove  34  formed in the spoiler  10  has protrusions  36  for fixing the supporting component  32 . The protrusions  36  may be shaped like an embankment extending along the groove  34 . The supporting component  32  is linearly formed from an elastic material such as rubber. The supporting component  32  has a supporting groove  38  and engagement grooves  40  extending in the longitudinal direction of the supporting component  32 . The supporting groove  38  supports the antenna element  16 , and the engagement grooves  40  engage with the protrusions  36  from the groove  34  in the spoiler  10 . By forming the supporting component  32  from an elastic material, the supporting component  32  can be attached to and detached from the groove  34  as desired. 
         [0043]    The supporting component  32  does not have to be provided over all segments of the groove  34  along which the antenna element  16  is present. In other words, the supporting component  32  may be provided only in a certain segment of the groove  34 . After the supporting component  32  is fitted into the groove  34  of the spoiler  10 , the antenna element  16  is fitted into the supporting component  32 . As a result, the antenna element  16  is fixed to the spoiler  10  with the supporting component  32  being interposed therebetween. 
         [0044]    By employing the above-described structure, the surface of the antenna element  16  is supported by the supporting component  32  over a large area. As a result, the antenna element  16  is securely fixed to the spoiler  10 . Further, because the supporting component  32  can be attached to and detached from the groove  34  as desired, the process of repeatedly changing the position of the supporting component  32  is easy. As a result, the characteristics of the spoiler antenna can be easily adjusted. 
         [0045]    Tabs may also be formed from grooves of a spoiler to fix an antenna element in the grooves.  FIG. 8  illustrates a structure wherein the antenna element  16  is fixed in the groove  34  using tabs  42 . As can be seen in  FIG. 8 , a pair of opposing tabs  42  are provided from opposing edges of an opening of the groove  34 . A portion of the antenna element  16  is covered by a tube  44  formed from an elastic material such as rubber. The antenna element  16  fitted into the groove  34  is fixed in the groove  34  with the tabs  42  holding the portion covered by the tube  44 . When the tube  44  formed from an elastic material is used, the tube  44  exerts an elastic force on the antenna element  16  and securely fixes the antenna element  16  in the groove  34 . Further, the material for forming the tube  44  or the shape of the tube  44  may be determined such that the antenna element  16  can be attached to and detached from the groove  34  as desired. 
         [0046]    By employing the above-described structure, the antenna element  16  is securely fixed to the spoiler  10 , as with the structure in which the supporting component is used. Further, when the antenna element  16  can be attached to and detached from the groove  34  as desired, characteristics of the spoiler antenna can be easily adjusted. 
         [0047]    In the above-described examples, the present invention is used for spoiler antennas. The present invention may also be used for antennas including an antenna element fixed to a bumper, a console, or another accessory. Further, the present invention may be used not only for receiver antennas, but also for transmitter antennas or transceiver antennas. For example, the present invention may be used for a transceiver that supports LTE (Long Term Evolution).