Patent Publication Number: US-2022238988-A1

Title: Vehicle exterior device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of International Application No. PCT/JP2020/027801, filed on Jul. 17, 2020, which claims priority to and the benefit of Japanese Patent Application No. 2019-189922, filed on Oct. 17, 2019. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF INVENTION 
     1. Field 
     The present invention relates to a vehicle exterior device on which additional functional components are mounted. 
     2. Description of Related Art 
     Vehicular antenna devices having streamlined external shapes, such as so-called shark fin antennas, have been known. Such antenna devices are excellent in design when being installed on roof panels, and have therefore recently been used for many vehicles. 
     An example of such antenna devices includes a functional component such as a camera, in addition to an antenna element for receiving AM and FM broadcast, to improve functionality (refer to WO 2018/079199, for example). A double cover structure constituted by an exterior case and an inner case is employed, electronic components such as a circuit board are housed in the inner case, and the functional component is supported by the inner case. Because components that needs to be protected against moisture are all put inside the inner case, the exterior case is not constrained by a structure for waterproof performance. This is advantageous in improving the design. 
     Related Art List 
     (1) WO 2018/079199 
     In the meantime, with recent improvement in vehicle performance, the functions required of antenna devices have been increasing. Specifications supporting GPS and GNSS in addition to AM and FM broadcast may be required. Furthermore, specifications additionally including functional components such as a light emitting module to improve the design have also been proposed. As the number of internal components increases accordingly, it becomes difficult to ensure installation space therefor. The inner case may be increased in size to allow sufficient space, which, however, results in a larger antenna device as a whole including the exterior case. The increase in size cannot be achieved in a case where a height limit is set on the antenna device in terms of design and specification. It is therefore important to find ways to achieve space saving, and the double cover structure is a factor preventing space saving. 
     Note that achievement of both waterproof performance and space saving can be necessary for not only antenna devices but also any device on a vehicle exterior (hereinafter referred to as a “vehicle exterior device”). For example, a vehicle exterior device on which no antenna element is mounted also needs to prevent entry of moisture into a vehicle interior via an insertion hole through which a cable for a functional component (such as a light emitting module or a camera) passes. It is therefore important to secure the functions of sealing portions. 
     SUMMARY OF INVENTION 
     In view of the above and other circumstances, one of objects of the present invention is to provide a vehicle exterior device that achieves space saving and sufficient waterproof performance. 
     An embodiment of the present invention is a vehicle exterior device. The vehicle exterior device includes: a base member; a cover attached to the base member in a watertight manner, the cover and the base member forming a housing space therebetween, the cover having at least one opening; a functional unit including a holder located on the base member in the housing space, and a functional component supported by the holder with a leading end thereof being exposed through the opening; and a sealing portion located around the opening between an outer face of the functional unit and an inner face of the cover. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1A and 1B  are external views of an antenna device according to a first embodiment; 
         FIG. 2  is an exploded perspective view of the antenna device; 
         FIG. 3  is a cross-sectional view along arrows A-A in  FIG. 1B ; 
         FIG. 4  is an enlarged view of part B in  FIG. 3 ; 
         FIGS. 5A to 5D  illustrate a method for attaching a sealing portion; 
         FIGS. 6A to 6C  illustrate a method for attaching a sealing portion; 
         FIG. 7  is an exploded perspective view of an antenna device according to a second embodiment; 
         FIGS. 8A to 8E  illustrate a structure of a holder; 
         FIGS. 9A to 9E  illustrate a structure of a sealing member; 
         FIG. 10  is a partially enlarged cross-sectional view illustrating a camera unit and surrounding structures; 
         FIG. 11  is a partially enlarged cross-sectional view of a main part of an antenna device according to a modification; 
         FIG. 12  is an exploded perspective view of an antenna device according to a third embodiment; 
         FIGS. 13A to 13E  illustrate a structure of a sealing member; and 
         FIG. 14  is a partially enlarged cross-sectional view illustrating a camera unit and surrounding structures. 
     
    
    
     DETAILED DESCRIPTION 
     Certain embodiments of the present invention will now be described with reference to the drawings. This is not intended to limit the scope of the present invention but to exemplify the invention. 
     The embodiments of the present invention will now be described in detail with reference to the drawings. In the following embodiments and modifications thereof, components that are substantially the same will be designated by the same reference numerals and redundant description thereof may be omitted as appropriate. 
     In each embodiment, an antenna device is presented as an example of a vehicle exterior device. The antenna device has a single cover structure for saving space so as to mount a plurality of antenna elements and a functional component. The cover has, on a side face thereof, an opening through which part of a functional component can be exposed. A waterproof structure is designed to simply and effectively prevent entry of moisture through the opening. Details thereof will be described below. 
     First Embodiment 
       FIGS. 1A and 1B  are external views of an antenna device according to a first embodiment.  FIG. 1A  is a perspective view, and  FIG. 1B  is a rear view. In the description below, for convenience of explanation, the positional relationship in the antenna device may be expressed in the front-back direction, the vertical direction, and the width direction in a state in which the antenna device is mounted on a vehicle. 
     The antenna device  1  is a low profile antenna device that is so-called a shark fin antenna, to be attached onto a roof panel of a vehicle, which is not illustrated. The antenna device  1  includes a base member  10 , which constitutes a bottom thereof, and a cover  12  attached to the base member  10  in a watertight manner. The cover  12  is made of radio wave transparent plastic (such as ABS, PET, or PC). A housing space is formed between the base member  10  and the cover  12 , in which the antenna elements and circuit boards thereof, which will be described later, are housed. 
     The base member  10  has an oval or triangular shape in plan view with its width gradually decreasing from back to front. A roof fixing portion  14  for fixing the antenna device  1  to the roof panel is disposed to protrude from the middle of a lower face of the base member  10 . The roof fixing portion  14  is inserted in an attaching hole formed through the roof panel. A nut is fastened to the roof fixing portion  14  with a ground washer therebetween, so that the base member  10  is fixed to the roof panel. 
     The cover  12  has a triangular shape in front view, and has a streamline shape (shark fin shape) with its height gradually decreasing and its width gradually decreasing from back to front. An opening lower end of the cover  12  is attached along a circumferential edge of the base member  10 . The cover  12  has a back face with an opening  16 , through which a leading end of the camera  20  (functional component) is exposed. 
       FIG. 2  is and exploded perspective view of the antenna device  1 . 
     The antenna device  1  includes a circuit board  22 , a support member  24 , an antenna element  26 , a camera unit  28 , and so on, which are attached onto the base member  10  and covered by the cover  12 . The support member  24  is a member for supporting the antenna element  26 . The antenna element  26  is receive radio waves of AM and FM broadcast, and is connected with the circuit board  22  via an antenna coil, which is not illustrated. The camera unit  28  includes the camera  20 , and functions as a “functional unit”. 
     The base member  10  includes an antenna base  30  and a seal pad  32 . The antenna base  30  is a conductive base made of die-cast aluminum, or may alternatively be made of stainless steel or other conductive metal. The roof fixing portion  14  is integrated with the antenna base  30 . The nut is fastened to the roof fixing portion  14  as described above, which causes the ground washer to break through a coating of the roof panel, and the middle part of the lower face of the antenna base  30  is electrically connected with the roof panel. This enables the antenna device  1  to ground to the vehicle body. 
     The seal pad  32  is an insulator made of flexible resin (rubber, for example) for sealing between the antenna base  30  and the roof panel. The seal pad  32  is slightly larger than the antenna base  30 . A peripheral edge of the seal pad  32  is folded inward to form a recessed fitting portion  33 . The seal pad  32  is placed to cover the antenna base  30  with the circumferential edge of the antenna base  30  fitted in the recessed fitting portion  33  to form the base member  10 . The cover  12  is attached to the base member  10  in a watertight manner with the seal pad  32  between the cover  12  and the antenna base  30 . 
     A plurality of bosses for screwing components stand on the top face of the antenna base  30 . The antenna base  30  has, at the center thereof, an insertion hole  34  through which a cable passes. The seal pad  32  has, at the center thereof, an insertion hole  36  through which a lower face of a middle portion of the antenna base  30  is exposed and through which the cable passes. The roof fixing portion  14  is placed through the insertion hole  36 . 
     Circuits such as an amplifier for amplifying signals received by the antenna element  26 , and a patch antenna  38  and circuits thereof are mounted on the circuit board  22 . The patch antenna  38  includes an antenna element for GPS, for example. The circuit board  22  is fixed to a front area of the antenna base  30 . 
     A guiding member  40  is fixed to a central area of the antenna base  30 , and the support member  24  is fixed over the guiding member  40 . The guiding member  40  is a member for guiding a cable  58  of the camera  20 . The guiding member  40  and the support member  24  are made of insulating materials (resin). The support member  24  extends above the antenna base  30 , and has an upper face being a supporting face  44  extending in the front-back direction. 
     The antenna element  26  is produced by bending a conductive metal sheet, and has a bifurcated shape. The antenna element  26  includes a body  46  extending in parallel with the supporting face  44 , and extending portions  48  extending obliquely downward from respective sides of the body  46 . While the antenna element  26  has a V-shaped cross section in the present embodiment, the antenna element  26  may have a U-shaped cross section or other shapes. 
     The antenna element  26  is fixed to the support member  24  with the body  46  placed on the supporting face  44 . In this manner, the antenna element  26  is held at a high position, and placed not to overlap with the circuit board  22  in plan view, to improve the receiving performance. 
     The camera unit  28  includes the camera  20  attached to a holder  50 . The holder  50  is fixed to the antenna base  30 , and the camera  20  is supported by the holder  50 . A seal ring  54  is arranged between the camera  20  and the holder  50 . The seal ring  54  is an O ring that functions as a “second sealing portion” in the present embodiment. 
     A seal ring  56  is attached to a leading end face (on the side of the opening  16  of the cover  12 ) of the holder  50 . The seal ring  56  is made of urethane foam, and functions as a “first sealing portion” in the present embodiment. Examples of the urethane foam include PORON (registered trademark), which is a microcellular polymer sheet. The seal ring  56  has an appropriate elasticity, and is softer than the seal ring  54 . The seal ring  56  has a compressibility (approximately 30%) higher than that (approximately 20%) of the seal ring  54 . Details of these sealing members will be described later. 
     The cable  58  extends from the camera  20 . The cable  58  is a coaxial cable that is guided by the guiding member  40  and drawn out of the antenna device  1  via the insertion holes  34  and  36 . A cable connected with the circuit board  22  is similarly drawn out. These cables are drawn into the vehicle body via a cable entry hole formed through the roof panel. 
       FIG. 3  is a cross-sectional view along arrows A-A in  FIG. 1B .  FIG. 4  is an enlarged view of part B in  FIG. 3 . 
     As illustrated in  FIG. 3 , an annular protrusion  60  is formed near and along the circumferential edge of the opening lower end of the cover  12 . The cover  12  is attached to the base member  10  with the end of the annular protrusion  60  biting into the upper face of the seal pad  32 , so that watertightness between the cover  12  and the base member  10  is achieved. The cover  12  and the antenna base  30  are fixed to each other with a plurality of screws  62  (one of which is illustrated in  FIG. 3 ). 
     A housing space S is formed between the cover  12  and the base member  10 . The components including the antenna element  26 , the circuit board  22 , and the camera unit  28  are arranged in the housing space S. In the present embodiment, because a single cover type is employed in the antenna device  1 , the internal components, such as the circuit board  22 , that need to be protected against moisture are exposed to the housing space S as illustrated. 
     The holder  50  is fixed to a back area of the antenna base  30 . An insertion hole  64  is formed through the holder  50  in the front-back direction. The insertion hole  64  coaxially communicates with the opening  16  of the cover  12 . The camera  20  is inserted in the insertion hole  64  and supported by the holder  50 . A plurality of fixing portions are formed to protrude from the outer circumferential face of the camera  20 , and fixed to the holder  50  with screws (not illustrated). A leading end (lens part) of the camera  20  is exposed to the opening  16 . 
     A connector  70  for the cable  58  is connected to the back face of the camera  20 . A supporting portion  72  is formed to protrude from the middle of the antenna base  30 . The cable  58  is guided by the supporting portion  72  and the guiding member  40 , and drawn downward through the insertion hole  34 . 
     As illustrated in  FIG. 4 , the inner circumferential face of the holder  50  has a tapered face  55  with its diameter gradually decreasing backward (toward the opening  16 ). The outer circumferential face of the camera has a stepped portion  57  with its diameter decreasing backward. The seal ring  54  is fitted to the stepped portion  57 . The camera  20  is inserted into the holder  50  from the front (left in the drawing), and the fixing portions  66  come in contact with the front end face of the holder  50 . This defines the insertion position of the camera  20  in the holder  50  (that is, the position of the camera  20  relative to the holder  50 ). 
     The seal ring  54  is arranged between the inner circumferential face of the holder  50  and the outer circumferential face of the camera  20  to prevent entry of moisture into the housing space S via a gap between the holder  50  and the camera  20 . More specifically, the seal ring  54  is axially and radially compressed between the stepped portion  57  of the camera  20  and the tapered face  55  of the holder  50 , and fulfills the sealing function. 
     The seal ring  56  is arranged between an open end of the holder  50  and the inner circumferential face of the cover  12  and extends around the opening  16 . This prevents entry of moisture into the housing space S via a gap between the holder  50  and the cover  12 . More specifically, the seal ring  56  is axially compressed between the back end (open end) of the holder  50  and the inner circumferential face of the back side of the cover  12 , and fulfills the sealing function. 
     Although entry of moisture into the opening  16  is permitted, the two seal rings  54  and  56  make the space inner than the camera unit  28  waterproof. Although the leading end (lens part) of the camera  20  is exposed to the opening  16  for imaging of the outside, this is not a problem because the camera (functional component) itself is waterproof. 
     A communication hole  78  extending downward from the opening  16  is formed in a back wall of the cover  12 . In addition, a slit  80  (cutout) in the up-down direction is formed in a back portion of the seal pad  32 . The communication hole  78  communicates with the slit  80 . The communication hole  78  is thus open to the outside (atmosphere) of the cover  12 . 
     The inner circumferential face of the holder  50  has an inclined face  82  on the back side of the tapered face  55 . The inclined face  82  is a tapered face with its diameter increasing toward the open end of the holder  50 . A stepped area  17  that communicates with the communication hole  78  is formed under the opening  16 . As illustrated, the inner diameter of the seal ring  56  is substantially equal to but slightly larger than the inner diameter of the open end of the holder  50 . The bottom of the stepped area  17  is at a position slightly lower than the inner circumference of the seal ring  56 . In this structure, an exposure space S 2 , which is outside of the seal ring  54  and surrounded by the holder  50  and the camera  20 , communicates with the communication hole  78  via the opening  16 . Thus, even if moisture is accumulated in the exposure space S 2 , the moisture is likely to be guided along the inclined face  82  to the communication hole  78  and discharged to the outside. 
       FIGS. 5A to 5D  and  FIGS. 6A to 6C  illustrate a method for attaching the sealing portions.  FIGS. 5A to 5D  illustrate processes for attaching the second sealing portion, and  FIGS. 6A to 6C  illustrate processes for attaching the first sealing portion. 
     As illustrated in  FIGS. 5A to 5D , for attaching the second sealing portion, the seal ring  54  is firstly put around the camera  20  ( FIG. 5A ). The seal ring  54  is fitted to the stepped portion  57 . 
     Subsequently, the camera  20  is inserted into the insertion hole  64  of the holder  50  ( FIG. 5B ). At this point, the seal ring  54  receives a compressing force in the radial direction in the process of insertion into the insertion hole  64  ( FIG. 5C ). The seal ring  54  having reached the tapered face  55  is also compressed in the axial direction, and compressed harder in the radial direction ( FIG. 5D ). The seal ring  54  thus fulfills a sufficient sealing function. In this state, screws, which are not illustrated, are fastened, and the camera  20  is thus fixed to and supported by the holder  50 . 
     As illustrated in  FIGS. 6A to 6C , for attaching the first sealing portion, the seal ring  56  is set in advance on the leading end face of the holder  50 . Specifically, the seal ring  56  is adhered to the holder  50  with a double sided tape. All the components to be mounted, such as the antenna element  26  and the camera unit  28 , are attached to the base member  10 . The cover  12  is placed over the base member  10  from above ( FIG. 6A ). In this process, the cover  12  is slightly shifted backward relative to the base member  10  so that the cover  12  does not interfere with the seal ring  56 . 
     Subsequently, in a state in which the inner face of the back side of the cover  12  faces the seal ring  56 , the cover  12  is shifted frontward to be positioned at the attaching position relative to the base member  10  ( FIG. 6B ). In this process, the seal ring  56  is axially compressed, and thus fulfills a sufficient sealing function. In this state, the screws  62  are fastened, and the cover  12  and the base member  10  are thus fixed to each other ( FIG. 6C ). In this manner, the sealing with the first sealing portion and the second sealing portion is achieved. 
     As described above, in the present embodiment, in attaching processes for the antenna device  1 , the seal ring  54  is radially compressed as the camera  20  is inserted in the holder  50 , which enables the seal ring  54  to fulfill a sufficient sealing function. Furthermore, the seal ring  56  is axially compressed as the cover  12  is attached to the base member  10 , which enables the seal ring  56  to fulfill a sufficient sealing function. In other words, the dimensions of the sealing members are set in view of the sizes of gaps between components and the attaching orientations thereof, which enables sufficient sealing effects to be produced only by using the attaching processes without any substantial change. The two sealing portions therefore simply and reliably fulfill the sealing functions. 
     Furthermore, using the single cover of the cover  12  only allows for enough room in the housing space S. Thus, the antenna device  1  can be kept compact even when the internal components thereof has increased. According to the present embodiment, the antenna device  1  therefore achieves space saving and sufficient waterproof performance. 
     In particular, in the present embodiment, urethane foam, which is resistant to water and easy to provide sufficient thickness and softness, is used as the first sealing portion. The urethane foam functions as an elastic body having a relatively high compressibility. Thus, even if the installation error is increased due to the superimposed dimensional tolerances caused by an increase in internal components or the like, the installation error can be absorbed at the first sealing portion. 
     Second Embodiment 
       FIG. 7  is an exploded perspective view of an antenna device according to a second embodiment. 
     An antenna device  201  of the present embodiment is different from that in the first embodiment. In the present embodiment, the first sealing portion and the second sealing portion are integrated as a single sealing member. Hereinafter, the description will focus on the differences from the first embodiment. 
     The antenna device  201  includes the circuit board  22 , the support member  24 , the antenna element  26 , a camera unit  228 , and so on, which are attached onto the base member  10 , and covered by the cover  12 . The camera unit  228  functions as a “functional unit”. A holder  250  included in the camera unit  228  has a shape different from the holder  50  in the first embodiment. A sealing member  252  is attached to the holder  250 . 
       FIGS. 8A to 8E  illustrate a structure of the holder  250 .  FIG. 8A  is a diagonal view from the front side,  FIG. 8B  is a front view,  FIG. 8C  is a side view, and  FIG. 8D  is a rear view.  FIG. 8E  is a cross-sectional view along arrows C-C in  FIG. 8D . 
     The holder  250  includes a base portion  260  to be fixed to the base member  10 , a support portion  262  vertically standing on the base portion  260 , and an insertion and fitting portion  264  coupled to the support portion  262 . The insertion and fitting portion  264  has a stepped cylindrical shape, and has an inner circumferential face that is substantially complementary to the shape of the outer circumferential face of the camera  20 . The support portion  262  is a wall at the front end of the insertion and fitting portion  264 , and has a plurality of screw holes  268  for screws for fixing the camera  20 . 
       FIGS. 9A to 9E  illustrate a structure of the sealing member  252 .  FIG. 9A  is a diagonal view from the front side,  FIG. 9B  is a front view,  FIG. 9C  is a side view, and  FIG. 9D  is a rear view.  FIG. 9E  is a cross-sectional view along arrows D-D in  FIG. 9D . 
     The sealing member  252  is made of urethane foam, and includes a cylindrical fitting portion  274  having a stepped cylindrical shape including a rectangular cylindrical portion  273  and a circular cylindrical portion  275 . The cylindrical fitting portion  274  has an inner circumferential face that is complementary to the shape of the outer circumferential face of the camera  20 , and an outer circumferential face that is complementary to the shape of the inner circumferential face of the holder  250 . The circular cylindrical portion  275  has, at a leading end thereof, a fitting and attaching portion  276  having a folded-back shape with an L-like cross section. A rib  280  is formed along the inner circumferential face of the circular cylindrical portion  275 . Annular ribs  282  and  284  are concentrically formed on the end face of the fitting and attaching portion  276 . The ribs  282  and  284  function as the “first sealing portion”, and the rib  280  functions as the “second sealing portion”. 
       FIG. 10  is a partially enlarged cross-sectional view illustrating the camera unit  228  and its surrounding structures. 
     The sealing member  252  is attached to the inner face of the holder  250  with the fitting and attaching portion  276  fitted to the insertion and fitting portion  264 . When the camera  20  is inserted into the insertion hole  64 , the sealing member  252  is positioned between the outer circumferential face of the camera  20  and the inner circumferential face of the holder  250 . Specifically, the cylindrical fitting portion  274  of the sealing member  252  is positioned between the outer circumferential face of the camera  20  and the insertion and fitting portion  264  of the holder  250 . In this process, the rib  280  formed on the insertion and fitting portion  264  is radially compressed, and fulfills the sealing function. 
     In addition, when the cover  12  is attached to the base member  10 , the fitting and attaching portion  276  of the sealing member  252  is positioned between the insertion and fitting portion  264  of the holder  250  and the inner circumferential face of the cover  12 . In this process, the ribs  282  and  284  are at positions surrounding the opening  16 , and compressed in the axial direction of the sealing member  252 . This achieves the sealing function. 
     In the present embodiment as well, sufficient sealing effects are produced only by using the attaching processes without any substantial change, and the two sealing portions simply and reliably fulfill the sealing functions. Furthermore, the antenna device  201  achieves space saving and sufficient waterproof performance. Because the two sealing portions are formed integrally as a single sealing member, the number of processes for installation can be reduced, and the manufacture cost can also be reduced. 
     Note that, in the present embodiment as well, the exposure space S 2  outside of the rib  280  communicates with the communication hole  78  via the opening  16 . Thus, even if moisture is accumulated in the exposure space S 2 , it can be discharged to the outside via the communication hole  78 . 
     Modification 
       FIG. 11  is a partially enlarged cross-sectional view illustrating a main part of an antenna device according to a modification. 
     In this modification, a sealing member  292  is made of urethane foam, and has a fitting and attaching portion  277  to be fitted to the insertion and fitting portion  264  of a holder  270 . The sealing member  292  is different from the sealing member  252  of the second embodiment in the arrangement of ribs. 
     Specifically, annular ribs  294  and  296  are concentrically formed on the outer circumferential face of the fitting and attaching portion  277 . The ribs  294  and  296  function as the “first sealing portion”. An annular inner face  213  is formed on the inner side of a cover  212 . The annular inner face  213  and the opening  16  are coaxial. The ribs  294  and  296  are inserted in the inner face  213 , radially compressed, and thus fulfill the sealing function. 
     The first sealing portion according to the present modification is radially compressed owing to the dimensional difference between the inner diameter of the inner face  213  in the cover  212  and the outer diameter of the fitting and attaching portion  277 . Thus, the compressibility thereof tends to be smaller than the type that is axially compressed like the first sealing portion in the second embodiment. In other words, the structure enabling axial compressing like that in the second embodiment achieves a better sealing performance. 
     Third Embodiment 
       FIG. 12  is an exploded perspective view of an antenna device according to a third embodiment. 
     An antenna device  301  according to the present embodiment is different from those in the first and the second embodiments. In the present embodiment, the first sealing portion and the second sealing portion are both positioned between the camera and the cover. Hereinafter, the description will focus on the differences from the first and the second embodiments. 
     The antenna device  301  includes the circuit board  22 , the support member  24 , the antenna element  26 , a camera unit  328 , and so on, which are attached onto the base member  10 , and covered by a cover  312 . The camera unit  328  functions as a “functional unit”. The camera unit  328  includes a holder  350  and the camera  20 . A sealing member  352  is attached to the holder  350 . 
       FIGS. 13A to 13E  illustrate a structure of the sealing member  352 .  FIG. 13A  is a diagonal view from the front side.  FIG. 13B  is a front view,  FIG. 13C  is a side view, and  FIG. 13D  is a rear view.  FIG. 13E  is a cross-sectional view along arrows E-E in  FIG. 13D . 
     The sealing member  352  is made of urethane foam, and has a cylindrical body  374 . A back part of the body  374  has a tapered portion  376  with its diameter decreasing backward. The tapered portion  376  has, on its inner side, a flat face perpendicular to the axis. An annular rib  380  is formed to protrude from the flat face. Annular ribs  382  and  384  are concentrically formed to protrude from the outer circumferential face of the tapered portion  376 . The ribs  382  and  384  function as the “first sealing portion”, and the rib  380  functions as the “second sealing portion”. 
       FIG. 14  is a partially enlarged cross-sectional view illustrating the camera unit  328  and its surrounding structures. 
     The camera  20  is attached to the holder  350  from the back, and fixed with a plurality of screws (not illustrated). The holder  350  has an insertion hole  364  that is widely open to the back, in which the camera  20  is partially contained. The holder  350  also has, at the center of the front end thereof, an insertion hole  365  with a small diameter. The connector  70  is inserted in the insertion hole  365  and connected with the camera  20 . 
     The sealing member  352  has an inner circumferential face that is complementary to the shape of the outer circumferential face of the back side of the camera  20 . In addition, an annular inner face  313  is formed on the inner side of the cover  312 . The annular inner face  313  and the opening  16  are coaxial. The inner face  313  has an inverse tapered shape that is complementary to the shape of the outer circumferential face of the tapered portion  376 . The ribs  382  and  384  protrude toward the inner face of the cover  312 , and the rib  380  protrudes toward the outer circumferential face of the camera  20 . When the cover  312  is attached to the base member  10 , the tapered portion  376  is positioned between the inner face  313  and the camera  20 . As a result, the ribs  380 ,  382 , and  384  are compressed in the axial direction of the sealing member  352 , and fulfill the sealing functions. 
     In the present embodiment as well, sufficient sealing effects are produced only by using the attaching processes without any substantial change, and the two sealing portions simply and reliably fulfill the sealing functions. Furthermore, the antenna device achieves space saving and sufficient waterproof performance. Because the two sealing portions are formed integrally as a single sealing member, the number of processes for installation can be reduced, and the manufacture cost can also be reduced. 
     Note that, in the present embodiment as well, the exposure space S 2  outside of the rib  380  communicates with the communication hole  78  via the opening  16 . Thus, even if moisture is accumulated in the exposure space S 2 , it can be discharged to the outside via the communication hole  78 . 
     Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments and it goes without saying that various modifications could be further developed within the technical idea underlying the present invention. 
     In the embodiments described above, a camera is presented as an example of the functional component included in the functional unit. In a modification, a light guide (light emitting module) or other functional components may be used. For example, an LED unit may be supported by a holder, and a leading end portion of the LED unit may be exposed through the opening. Alternatively, a plurality of functional components may be provided, and the leading ends of the respective functional components may be individually exposed through openings of the cover. For each of the functional units, a waterproof structure in the embodiments and modifications described above can be applied to the functional unit around the opening. 
     In the embodiments described above, examples are presented in which the antenna base and the seal pad are provided as separate members and attached to each other to form the base member. In a modification, the antenna base and the seal pad may be formed integrally by molding using a mold. The seal pad may be made of flexible molding resin. 
     In the embodiments described above, the base member is constituted by a plurality of components (the antenna base and the seal pad). In a modification, the base member may be constituted by a single member. Specifically, the base member may be constituted only by an antenna base made of resin, and the joint between the cover and the antenna base may be sealed in a watertight manner by welding, adhesion, or the like. In the former case, with the cover and the antenna base attached, they can be joined by laser irradiation along their circumferential edges. 
     In the embodiments described above, the antenna base is constituted by a single member. In a modification, the antenna base may be constituted by a plurality of members. For example, a first base made of metal (hereinafter referred to as a “metal base”) and a second base made of resin (hereinafter referred to as a “resin base”) may be attached to each other to form an antenna base. An opening may be formed in a central area of the resin base, and the metal base may be attached in such a manner as to close the opening. An insertion hole through which a cable passes may be formed at the center of the metal base. The roof fixing portion may be integrated with the metal base. A lower face of the metal base is electrically connected with the roof panel. The resin base may be covered by a seal pad. Alternatively, the cover and the resin base may be joined together in a watertight manner by welding or the like without a seal pad. 
     In the embodiments described above, the support member for supporting the antenna element and the holder for supporting the functional components are separate members. In a modification, the support member and the holder may be formed integrally. A part corresponding to the support member may be formed as part of the “holder”. 
     In the embodiments described above, examples are presented in which the holder and the antenna base are separate members, and the holder is fixed to the antenna base (base member). In a modification, the antenna base and the holder may be formed integrally. For example, a protrusion or the like may be molded integrally with the antenna base (resin base) by injection molding of a resin material, and the protrusion may function as a holder. A holder may be formed as part of the antenna base. Specifically, the holder may be in any form as long as it is located on the “base member”. 
     In the embodiments described above, examples of the structure are presented in which the antenna element is arranged in the housing space surround by the cover and the base member. In a modification, an antenna element may constitute part of the cover. An antenna element may be formed integrally with the cover by molding. In this case, the antenna element may be buried in the cover or may be partially exposed to the outside. Note that the “antenna element” used here may be any element constituting an antenna, and may be in any form (plate, coil, or other shapes). 
     In the embodiments described above, urethane foam, which is excellent in waterproof performance and has a relatively high compressibility, is employed as the first sealing portion. In a modification, an elastomer, rubber, or other elastic bodies having a sealing function may be employed. For example, ethylene propylene diene monomer (EPDM) rubber is suitable as an elastic body excellent in waterproof performance. 
     In the first embodiment, a material used for the first sealing portion is different from that for the second sealing portion. Specifically, a material having a higher compressibility and being softer than the second sealing portion is used for the first sealing portion. In a modification, a material may be used for both of the sealing portions. The material for both of the sealing portions may be an elastic body such as urethane foam. Alternatively, the sealing portions may be O rings. 
     In the second embodiment, an example of a structure is presented in which two ribs  282  and  284  are formed on the end face of the sealing member  252  and one rib  280  is formed on the inner circumferential face thereof. In the third embodiment, an example of a structure is presented in which two ribs  382  and  384  are formed on the outer circumferential face of the sealing member  352  and one rib  380  is formed on the inner circumferential face thereof. In other words, the first sealing portion is constituted by two ribs, and the second sealing portion is constituted by one rib. In a modification, the first sealing portion may be constituted by three or more ribs, or by a single rib. The second sealing portion may be constituted by a plurality of ribs. A rib constituting the first sealing portion and a rib constituting the second sealing portion may have different heights from each other. The structure such as the shape and the size of the first sealing portion may differ from that of the second sealing portion, so that the first sealing portion has a higher compressibility than the second sealing portion. 
     In the first and the second embodiments, examples are presented in which the first sealing portion is arranged between the holder and the cover, and the second sealing portion is arranged between the holder and the functional component (camera). In the third embodiment, an example is presented in which the first sealing portion and the second sealing portion are arranged between the holder and the functional component (camera). The “sealing portions” used herein fulfill the sealing function when the components are attached. In a modification, part of a functional component may have the function of the holder (a housing of a functional component may function as the holder). In addition, a single sealing member that functions as a “sealing portion” may be arranged between the outer face of the functional unit and the inner face of the cover. 
     While the antenna element  26  is made of metal in the embodiments described above, the antenna element  26  may be made of conductive resin or other conductive materials. 
     In the embodiments described above, examples are presented in which antenna elements applicable to AM, FM, and GPS are housed in the housing space of the antenna device. In a modification, antenna elements applicable to XM, GNSS, DAB, V2X, TEL, or the like may be housed. The antenna device may be a combined antenna device on which a plurality of antenna elements are mounted to support a plurality of frequency bands. 
     While examples of a shark fin antenna are presented in the embodiments described above, the space saving effect of the sealing structures described above is significantly produced for any low profile antenna device. Note that the sealing structures described above are not limited to application to low profile antenna devices, but are obviously applicable to any antenna device in which a housing space is formed between a cover and a base member. 
     While the antenna device is to be installed on a roof panel in the description of the embodiments, the antenna device may be installed at other positions of a vehicle body such as a spoiler or a trunk panel. 
     While examples of antenna devices are presented in the embodiments described above, the sealing structures described above may also be applied to a vehicle exterior device including no antenna element. The sealing structures may be applied to a vehicle exterior device, such as a light emitting device or an illumination device including a light emitting module, and an imaging device including a camera. 
     The present invention is not limited to the embodiments described above and modifications thereof, and any component thereof can be modified and embodied without departing from the scope of the invention. Components described in the embodiments and modifications can be combined as appropriate to form various inventions. Some components may be omitted from the components presented in the embodiments and modifications.