Patent Publication Number: US-7215291-B2

Title: Antenna device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-298027, filed Oct. 12, 2004, the entire contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an antenna device mounted on a vehicle body such as an automobile, and more particularly, to an antenna device capable of simplifying a mounting work and reliably making connection even in the case of a composite antenna capable of receiving a plurality of frequency bandwidths. 
   2. Description of the Related Art 
   Conventionally, it has been well known that a variety of antenna devices are mounted on a vehicle body of an automobile (for example, Jpn. Pat. Appln. KOKAI Publication Nos. 2001-36315 and 2004-48599).  FIGS. 14 and 15  are views each showing an example of such an antenna device. That is, an antenna device  1  is composed of: an antenna main body  2  provided at an upper side of a roof panel R; and a mount nut  10  provided at a lower side of the roof panel R. The antenna main body  2  comprises: an antenna cover  3 ; an antenna element  4  mounted on the antenna cover  3 ; a pad section  5  disposed between the antenna cover  3  and the roof panel R; and a base section (not shown) and a substrate  6  provided at the pad section  5 . A matching circuit or an amplifier circuit and a duplexer are incorporated in the substrate  6 . 
   A protrusion section  7  is provided on a lower face of the base section as shown in  FIG. 15 , and is inserted into an antenna mount hole. A through hole is formed at the inside of the protrusion section  7 , and an AM/FM coaxial cable  8  for transmitting a signal and a power supply line  9  for supplying power to the substrate  6  are drawn via the through hole. 
   The mount nut  10  comprises a ground washer  11  and a nut section  12 , and the ground washer  11  is assembled to be rotatable with respect to the nut section  12 . 
   In such an antenna device  1 , the antenna main body  2  is first mounted on the antenna mount hole of the roof panel R from overhead shown in  FIG. 15 . At this time, the antenna main body  2  is temporarily locked so as to be immobilized by a temporarily locking claw  7   b  or the like. Next, the coaxial cable  8  and the power supply line  9  are routed into a through hole of the protrusion section  7  of the pad section  5 . Then, the nut section  12  of the mount nut  10  is helically fitted to the screw section  7   a  formed on an outer periphery face of the protrusion section  7 . Further, when the nut section  12  is rotated, a triangle shaped distal end of the ground washer  11  is cut into a lower face side of the roof panel R shown in  FIG. 15 , and the antenna main body  2  is securely fixed to the roof panel R and is grounded. 
   The above-described antenna device has suffered from the following problem. That is, in recent year, an antenna device has often been configured as a composite antenna having incorporated therein a high frequency patch antenna such as GPS, mobile broadcast, ETC, or SDARS in addition to an AM/FM broadcast receiving antenna. Further, there may be a need for a power supply cable for use in an amplifier incorporated in the antenna main body. Therefore, the number of cables or the like must be routed into the antenna mount holes, resulting in complicated work. 
   In addition, there has been a need for a work of connecting their respective cables to vehicle side cables inside of the vehicle body, and there has been an increased worker&#39;s burden. Further, in the case of a connector for use in connecting a high frequency bandwidth cable, a range of an error allowable at the time of connection is very narrow, and thus, there has been a problem that skillfulness is required for a connection work. 
   Further, there has been a problem that work efficiency becomes low since the antenna main body is temporarily stopped in an unstable manner when the main body is positioned on the roof panel. Furthermore, since a worker must do a work with one&#39;s face being upwardly oriented, there has been a possibility that the ground washer or nut may be accidentally dropped. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide an antenna device capable of assembling an antenna main body in accordance with simplified procedures and capable of reliably connecting an antenna element and a cable to each other and reliably providing grounding. 
   The antenna device according to the invention is composed as follows. In the antenna device mounted on a mount hole provided in a plate material, there are provided: an antenna main body disposed on one face side of the plate material; and a fixing member disposed on the other face side of the plate material, the fixing member fixing the antenna main body to the plate material. The antenna main body comprises: an antenna element; a first connector electrically connected to the antenna element; a first screw section provided in a tightening direction in which an axial center line passes through the mount hole; and an engagement section inserted into the mount hole from the one side face, thereby achieving engagement on the other face side. The fixing member comprises a feeder line provided to make connection with the antenna element; a second connector provided to make mechanical engagement and electrical connection with the first connector; and a second screw section helically fitted to the first screw section, thereby tightening the antenna main body, the above fixing member, and the plate material with one another. 
   According to the invention, the antenna device can be assembled in accordance with simplified procedures, and makes it possible to reliably connecting the antenna element and cables to each other and reliably providing grounding. 
   Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
       FIG. 1  is a side view showing an antenna device according to a first embodiment of the present invention; 
       FIG. 2  is an exploded perspective view showing the antenna device from the lower side; 
       FIG. 3  is a longitudinal cross section showing the antenna device; 
       FIG. 4  is a plan view showing an antenna main body of the embodiment from a lower side when the main body is inserted into a roof panel; 
       FIG. 5  is a perspective view showing a fixing member of the embodiment; 
       FIG. 6  is a perspective view showing a process of assembling the antenna main body; 
       FIG. 7  is a perspective view showing a process of assembling the antenna main body; 
       FIG. 8  is a longitudinal section view showing a process of assembling the antenna device; 
       FIG. 9  is a longitudinal section view showing a process of assembling the antenna device; 
       FIG. 10  is a longitudinal section view showing a process of assembling the antenna device; 
       FIG. 11  is a longitudinal cross section showing an antenna device according to a second embodiment of the present invention in an exploded manner; 
       FIG. 12  is a plan view when the antenna device is seen in the direction indicated by the arrow in double dot and chain line α shown in  FIG. 11 ; 
       FIG. 13  is a plan view when the antenna device is seen in the direction indicated by the arrow in double dot and chain line β shown in  FIG. 11 ; 
       FIG. 14  is a side view showing a conventional antenna device for use in an automobile; and 
       FIG. 15  is an enlarged side view showing essential portions of the antenna device for use in an automobile. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a side view showing an antenna device  20  according to a first embodiment of the present invention;  FIG. 2  is an exploded perspective view showing the antenna device  20  from the lower side;  FIG. 3  is a longitudinal cross section showing the antenna device  20 ;  FIG. 4  is a plan view showing an antenna main body  30  from a lower side when the main body is inserted into a roof panel R;  FIG. 5  is a perspective view showing a fixing member  100 ;  FIGS. 6 and 7  are perspective views showing a process of assembling the antenna main body  30 ; and  FIGS. 8 to 10  are longitudinal section views showing a process of assembling the antenna device  20 . C in these figures indicates a tightening direction in which a screw is mounted by tightening a bolt  130  described later. In addition, R in these figures indicates a roof panel which configures a vehicle body such as an automobile, and H indicates an antenna mount hole. The antenna mount hole H is formed in a substantially rectangular shape, and a cutout H 1  is partly formed. 
   The antenna device  20  comprises the antenna main body  30  and the fixing member  100  as shown in  FIG. 1 . The antenna main body  30  comprises an antenna cover  31  and a pad  32  pinched between the antenna cover  31  and the roof panel R. An AM/FM antenna element  33  is mounted on the antenna cover  31 . 
   A base  40  is mounted on the pad  32  as shown in  FIG. 6 . A patch antenna  41 , a substrate  42 , and a first connector  50  are mounted on the base  40 . 
   The first connector  50 , as shown in  FIG. 3 , comprises: a rectangular plate shaped connector main body  51 ; a cylinder body  52  provided at a center part of a lower face side of the connector main body  51  shown in  FIG. 3 ; three female connectors  53  to  55  disposed at the periphery of the cylinder body  52  in parallel to an axial direction of the cylinder body  52 ; a terminal  56  provided at an upper face side of the connector main body  51  shown in  FIG. 3 , and connected to the female connectors  53  to  55 ; and a spring plate  57  erected from a side face of the connector main body  51 . A protrusion section  51   a  matching the cutout H 1  is formed on the side face of the connector main body  51 . 
   The cylinder body  2  has two types of internal diameters, and comprises an inner cylinder section  52   a  having a slightly larger diameter and a female screw section  52   b  having a slightly small diameter in which a female screw has been formed on its inner face. On an outer periphery face of the cylinder body  52 , a protrusion stripe section  52   c  is formed along an axial direction of the cylinder body  52 . 
   The spring plate  57  is formed so as to be slackened in a transverse direction shown in  FIG. 3  while the engagement claw  57   a  is formed at a distal end of the sprint plate. The engagement claw  57   a  is formed so as to engage with a peripheral edge at the vehicle inside (lower face in  FIG. 3 ) of the antenna mount hole H of the roof panel R. 
   The fixing member  100 , as shown in  FIG. 2 , comprises: a bottomed cylinder shaped cover body (grounding member)  101  made of an electrically conductive material, for example, stainless or nickel plated iron; a second connector  110 ; and a bolt  130 . In addition, a through hole  102  is formed at the cover body  101 , the through hole having formed therein a female screw helically fitted by a male screw section  133   b  of the bolt  130  described later. In addition, a wave washer (elastic body)  103  is disposed in a gap between the cover body  101  and the second connector  110  and biases the second connector  110  upwardly. 
   An engagement hole  101   a , a positioning hole  101   b , and a protrusion section  101   c  are formed on the cover body  101 . The engagement hole  101   a  restricts a movement other than a tightening direction of an engagement claw  120  described later by engaging it with the engagement claw  120 . The positioning hole  101   b  positions the cover body  101  and the second connector  110  due to a protrusion section  121  described later being inserted thereinto. The protrusion section  101   c  abuts against the roof panel R. 
   The engagement claw  120  is configured to engage the cover body  101  and the second connector  110  with each other and to prevent the second connector  110  from being connected to the first connector  50  by a predetermined force or more at the time of bolt tightening. Therefore, a length in the tightening direction of the engagement hole  101   a  is defined such that the second connector  110  is connected to the first connector  50  at a desired position based on a relationship with a biasing force of the wave washer  103  at the time of tightening of the bolt  130 . 
   The second connector  110 , as shown in  FIG. 3 , comprises: a rectangular prism shaped connector main body  111 ; a through hole  112  provided at a center part of the connector main body  111 , the above-described cylinder body  52  being inserted into the through hole; male connectors  113  to  115  disposed at the periphery of the through hole  112 , and provided to be connected to the above-described female connectors  113  to  115 ; a guide section  119  provided in parallel to the through hole  112 ; and an engagement claw  120  provided on a side face of the connector main body  111 . In addition, reference numeral  121  shown in  FIG. 2  denotes a protrusion section which restricts movement of the wave washer  103 . 
   The cylinder body  52  is provided so as to be freely inserted by the through hole  112  and the guide section  119  and is formed such that rotation in an axial direction of the cylinder body  52  is restricted by a protrusion stripe section  52   c.    
   The bolt  130  comprises: a nut  131 ; a washer  132  integrated with the nut  131 ; and a shaft body  133 . The shaft body  133  comprises: a shaft body section  133   a  having a slightly smaller diameter provided at the side of the nut  131 ; and a male screw section  133   b  having a slightly larger diameter provided at a distal end side. The male screw section  133   b  is provided so as to be helically fitted to the female screw  52   b  of the cylinder body  52 . 
   The thus configured antenna device  20  is assembled as follows. The antenna main boy  30  and the fixing member  100  are assembled in advance. The antenna main body  30  mounts the patch antenna  41  for high frequency bandwidth on the first connector  50  as shown in  FIG. 6 . Further, as shown in  FIG. 7 , the substrate  42  is mounted. From a terminal of the substrate  42 , connection to an antenna element  33  is made via a lead wire (not shown), and the antenna cover  31  is mounted. In addition, the fixing member  100  inserts the bolt  130  in advance into the through hole  102  of the cover body  101  as shown in  FIG. 8 . At this time, a female screw is formed in the through hole  102 . Thus, the male screw section  133   b  of the bolt  130  is threaded, thereby preventing the bolt  130  from slipping off from the cover body  101 . 
   The subsequent assembling process is roughly divided into three steps. That is, a first step is a step of temporarily locking the antenna main body  30 ; a second step is a step of temporarily locking the fixing member  100 ; and a third step is a step of tightening the bolt  130 . Now, each of these steps will be described below. 
   In the first step, first, the pad  32  is positioned at the periphery of the antenna mount hole H on the roof panel R and the first connector  50  is inserted into the antenna mount hole H. At this time, the spring plate  57  is bent inwardly by an edge part of the antenna mount hole H before passing through the antenna mount hole H, and then, passes through the mount hole H. Then, the spring plate returns to its original shape and protrudes from the antenna mount hole H, so that the engagement claw  57   a  engages with a back face of the roof panel R and the first connector  50  is temporarily locked with the roof panel R. This state is shown in  FIGS. 2 and 3 . 
   When the first connector  50  is inserted into the antenna mount hole H, the connector is mounted such that the protrusion section  51   a  coincides with the cutout H 1  in order to prevent incorrect orientation. 
   In the second step, as shown in  FIG. 9 , the male connectors  113  to  115  of the second connector  110  are inserted into the female connectors  53  to  55 . Mechanical engagement and temporary tightening are achieved at a time point when the male connectors  113  to  115  have been inserted to a predetermined depth of the female connectors  53  to  55 . At this time, electrical conduction is also achieved. 
   In the third step, as shown in  FIG. 10 , the male section  133   b  reaches the female screw section  52   b  of the cylinder body  52  when the bolt  130  is screwed. Then, the male section is helically fitted and tightened. The tightening of the bolt  130  is stopped at a time point when the washer  132  is compressed against the cover body  101  by a proper force. The protrusion section  101   c  of the cover body  101  cuts into the roof panel R, whereby grounding is provided. 
   According to the thus configured antenna device  20 , a first temporary lock is carried out by inserting the first connector  50  into the antenna mount hole H (first step); a second temporary lock is carried out by inserting the second connector  110  into the first connector  50 ; and lastly, fixing and grounding are carried out by tightening the bolt  130  (step  3 ). Accordingly, the antenna device  20  can be mounted on the antenna mount hole H of the roof panel R with a simplified work, and it becomes possible to reliably provide connection and grounding. 
   In addition, the second connector  110  can make connection between the male connectors  113  to  115  and the female connectors  53  to  55  each with respect to the cover body  101  in a predetermined design scope by means of working the engagement claw  120  and the engagement hole  101   a.    
   Since the second connector  110  has a floating structure along the tightening direction C with respect to the cover body  101 , and the wave washer  103  is arranged between the connector and the cover body  101 , the second connector  110  is biased to the side of the first connector  50  by the cover body  101  with a proper force. Therefore, the male connectors  113  and the female connectors  53  to  55  are always connected to each other in a proper range, so that a contact state is properly maintained. That is, in a signal having a high frequency bandwidth, there is a case where the signal is not properly transmitted due to a slight shift in the contact state. However, the male connectors  113  to  115  are engaged with the female connectors  53  to  55  with a proper force, as described above, thus making it possible to prevent a loss in connection portion. 
   As described above, according to the antenna device  20  of the first embodiment, the antenna main body  30  can be assembled in accordance with the simplified procedures. Moreover, the antenna element  33 , the pad antenna  41 , and the cables  116  to  118  are reliably connected to one another, making it possible to reliably provide grounding. 
   The biasing means may be made of another material instead of elastic material. For example, it may be a small strip that projects slantwise to a position where the first connector  50  contacts the second connector  110 . The strip can work as a blade spring. 
   By eliminating the wave washer  103  (elastic body), a similar function, i.e., a function of setting the second connector  110  to be connected to the first connector  50  at a desired position may be provided at the side of the first connector  50 . 
     FIG. 11  is a longitudinal cross section showing an antenna device  220  according to a second embodiment of the present invention in an exploded manner;  FIG. 12  is a plan view when the antenna device is seen in the direction indicated by the arrow in double dot and chain line α shown in  FIG. 11 ; and  FIG. 13  is a plan view when the antenna device is seen in the direction indicated by the arrow in double dot and chain line β shown in  FIG. 11 . C in these figures indicates a tightening direction in which a screw is mounted by tightening a nut  302  described later. 
   The antenna device  220  comprises an antenna main body  230  and a fixing member  300 . The antenna main body  230  comprises an antenna cover  231  and an AM/FM antenna element  232  mounted on the antenna cover  231 . 
   A base  240  is mounted at the inside of the antenna cover  231  as shown in  FIG. 11 . A patch antenna  241  and a substrate  242  are provided at an upper face side of the base  240 . In addition, a cylinder body  243  is provided at a lower face side of the case  240 , and a male screw  244  is formed on its outer periphery face. A cutout  243   a  is formed on the cylinder body  243 . Further, a first connector  250  is mounted on a lower face side of the substrate  242 . 
   The first connector  250  comprises a cylinder shaped connector main body  251 , and a temporary lock collar  252  engaged with an outer periphery wall of the connector main body  251 . The temporary lock collar  252  comprises an engagement claw  252   a  protruding to the outside from the cutout  243   a  provided at the cylinder body  243 . Three female connectors  253  to  255  are formed at the inside of the connector main body  251 . An engagement claw  252   a  is formed so as to slacken in a vertical direction shown in  FIG. 11 , and is formed such that its distal end engages with a peripheral edge of the vehicle inside (lower face in  FIG. 11 ) of the antenna mount hole H of the roof panel R. 
   The fixing member  300  comprises a cylinder shaped cover body (ground member)  301 , a nut  302  mounted to be rotatable with respect to the cover body  301 , and a second connector  310  provided in the cover body  301 . Cables  311  to  313  are connected to the second connector  310 , and these cables each are connected to the male connectors  314  to  316 , respectively. In addition, these male connectors  314  to  316  are connected to the female connectors  253  to  255 . 
   A cutout is provided at the cover body  301  along the axial center line direction C, and is configured such that the cables  311  to  313  can be drawn. A claw  301   a  grounded to be compressed against the roof panel R is provided on an upper end face of the cover main body  301 . In addition, a female screw  303  helically fitted to the above-described male screw  244  is formed on an inner wall face of the nut  302 . Further, a wave washer (elastic body)  304  for biasing the second connector  310  from the side of the cover body  301  to the side of the roof panel R is disposed at an inner face side of the cover body  301  to bias the second connector  310  to the upper side shown in  FIG. 1 . 
   The thus configured antenna device  220  is assembled as follows. As in the first embodiment, the antenna main body  230  and the fixing member  300  are assembled in advance. The subsequent assembling process is roughly divided into three steps. That is, a first step is a step of temporarily locking the first connector  250 ; a second step is a step of temporarily locking the second connector  310 ; and a third step is a step of tightening the nut  302 . Now, each of these three steps will be described below. 
   In the first step, the base  240  is positioned at the periphery of the antenna mount hole H on the roof panel R. Next, the first connector  250  is inserted into the antenna mount hole H. At this time, the engagement claw  252   a  is bent inwardly by an edge part of the antenna mount hole H before passing through the antenna mount hole H, and then, passes through the mount hole H. Then, this engagement claw returns to its original shape as illustrated, and protrudes from the antenna mount hole H. Thus, the engagement claw  252   a  engages with a back face of the roof panel R, and the first connector  250  is temporarily locked on the roof panel R. 
   In the second step, the male connectors  314  to  316  of the second connector  310  are inserted into the female connectors  253  to  255 . Mechanical engagement and temporary lock are achieved at a time point when the male connectors  314  to  316  are inserted into the female connectors  253  to  255  to a predetermined depth. At this time, electrical conduction is also achieved. 
   In the third step, the female screw section  303  reaches the male screw  244  when the nut  302  is tightened, and then, the female screw section is helically fitted and tightened. Tightening of the nut  302  is stopped at a time point when the nut  302  compresses the cover body  301  against the roof panel R with a proper force. The claw  301   a  of the cover body  301  is compressed against and cut into the roof panel R, whereby grounding is provided. 
   As described above, according to the antenna device  220  of the present embodiment, a first temporary lock is carried out by inserting the first connector  250  into the antenna mount hole H (step  1 ); a second temporary lock is carried out by inserting the second connector  310  into the first connector  250  (step S 2 ); and lastly, fixing and grounding are provided by tightening the nut  302  (step  3 ). Accordingly, the antenna device  220  can be mounted on the roof panel R by a simplified work, and it becomes possible to reliably provide connection and grounding. 
   The present invention is not limited to the above-described embodiments. For example, while the embodiments have explained connection in three sets of male connectors and female connectors, one or two sets of male connectors and female connectors may be used for actually make connections. In addition, the number of sets for making connections between the male connectors and the female connectors is not limited to three. Further, if a connection is made for use in frequency bandwidth, such a connection is not limited to the above-described connections. Of course, various modifications can occur with departing from the spirit of the invention. 
   Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.