JP2015084575A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device in which the width of an umbrella element can be narrowed while maintaining the reception performance equally, and the design can be improved by narrowing the width at the upper part of an antenna case.SOLUTION: The antenna device consists of an antenna case 10, an antenna base 11, an element holder 12, an umbrella element 13, an amplifier substrate 16, and a coil 14. The antenna case 10 is fitted to the antenna base 11. The element holder 12 is insulating and provided to stand on the antenna base 11. The umbrella element 13 is installed above the element holder 12 so as to be positioned substantially at the center of right and left. The coil 14 causes the umbrella element, inserted between the umbrella element 13 and the input end of an amplifier, to resonate at a predetermined frequency, and is secured to the element holder.

Description

  The present invention relates to a small and low-profile antenna device that can be mounted on an automobile.

2. Description of the Related Art Conventionally, an antenna device having a limited space such as a vehicle antenna device having an antenna case is known. The configuration of this conventional antenna device 100 is shown in FIGS. 41 is a side view showing the configuration of the conventional antenna apparatus 100, FIG. 42 is a side view showing the internal configuration of the conventional antenna apparatus 100, and FIG. 43 is an exploded view of the conventional antenna apparatus 100. is there.
The conventional antenna device 100 shown in these drawings is an antenna device that is attached to the roof of a vehicle, and when attached to the vehicle, the height protruding from the vehicle is about 66 mm, the width is about 63 mm, and the length is It is about 153 mm. The antenna device 100 is in a low posture and can receive AM broadcast and FM broadcast. The shape of the antenna device 100 is a streamlined shape that becomes thinner toward the tip. A flexible base pad made of rubber or elastomer is fitted to the lower surface of the antenna device 100 so that it can be attached to the vehicle in a watertight manner.

  The conventional antenna device 100 includes a resin antenna case 110, a metal antenna base 120 to which a lower portion of the antenna case 110 is fitted, an antenna substrate 130 that is vertically attached to the antenna base 120, and a parallel antenna board. The amplifier board 134 is attached to the antenna board 130, the top section 131 is formed so as to cross over the antenna board 130, and the GPS antenna 132 is attached to the antenna base 120. . The antenna case 110 is made of a radio wave permeable synthetic resin, and includes a streamlined outer shell portion 110a that becomes thinner toward the tip. In the antenna case 110, there are formed a space in which the antenna substrate 130 erected and a top portion 131 disposed on the antenna substrate 130 can be stored, and a space in which the amplifier substrate 134 is stored in the horizontal direction. A metal antenna base 120 is fitted on the lower surface of the antenna case 110. An antenna substrate 130 is erected and fixed to the antenna base 120, and an amplifier substrate 134 is fixed substantially parallel to the antenna base 120 in front of the antenna substrate 130. An antenna pattern is formed on the antenna substrate 130. A top portion 131 is built in the upper part of the antenna case 110. Then, by fitting the antenna case 110 to the antenna base 120, the top part 131 built in the antenna case 110 is arranged so as to straddle the upper part of the antenna substrate 130, and the connection fitting attached to the upper part of the antenna substrate 130. 136 comes into electrical contact with the inner surface of the top portion 131. Since the connection fitting 136 is electrically connected to the antenna pattern formed on the antenna substrate 130, the top portion 131 and the antenna pattern are connected via the connection fitting 136. As a result, an antenna element is configured by the antenna pattern and the top portion 131, and the antenna substrate 130, the top portion 131, and the amplifier substrate 134 are accommodated in the space inside the antenna case 110.

  On the antenna substrate 130, a coil 135 is provided for resonating an antenna element constituted by the antenna pattern and the top portion 131 in the vicinity of the FM waveband. One end of the coil 135 is connected to the antenna pattern, the other end of the coil 135 is connected to one end of the pattern formed on the antenna substrate 130, and one end of the connection line 133 is connected to the other end of the pattern. The other end of the connection line 133 is connected to an input portion of an AM / FM amplifier provided on the amplifier board 134, and an AM / FM reception signal received by an antenna element constituted by the antenna pattern and the top portion 131 is AM. The signal is input to the / FM amplifier and amplified. A bolt 121 for attaching the antenna device 100 to the vehicle is formed so as to protrude from the lower surface of the antenna base 120. A cable 122 for guiding a received signal from the antenna device 100 into the vehicle is led out from the lower surface of the antenna base 120. This cable 122 is led out from the amplifier board 134, and includes a cable for guiding the AM reception signal and the FM reception signal amplified by the AM / FM amplifier provided on the amplifier board 134, and is bundled by the collar 145. ing. In this case, holes through which the bolts 121 and the cables 122 are inserted are formed in the roof of the vehicle, and the antenna device 100 is placed on the roof so that the bolts 121 and the cables 122 are inserted through these holes. The antenna device 100 can be fixed to the roof of the vehicle by fastening a nut to the bolt 121 protruding into the vehicle. In addition, power to the amplifier board 134 housed in the antenna case 110 is supplied to the amplifier board 134 from the inside of the vehicle via the cable 122.

  The assembly of the conventional antenna device 100 will be described with reference to an exploded view shown in FIG. In the conventional antenna device 100, the top portion 131 is fixed to the upper portion of the antenna case 110 with two screws 140. A connection fitting 136 is fitted on the upper end of the antenna substrate 130. The connection fitting 136 is attached to the upper portion of the antenna substrate 130 by sandwiching the antenna substrate 130. In addition, the coil 135 is mounted on the antenna substrate 130 by soldering. The antenna substrate 130 is erected and fixed to the antenna base 120 by two screws 141. The amplifier board 134 is disposed in front of the antenna board 130 and is fixed to the antenna base 120 almost in parallel with the three screws 142. A cable 122 for outputting the amplified AM reception signal and FM reception signal is led out from the amplifier board 134, a terminal 143 is attached to the tip of the cable 122, and the terminal 143 is fixed to the back surface of the amplifier board 134. In addition, one end of a wire-like connection line 133 is connected to the antenna substrate 130, and the other end of the connection line 133 is connected to the amplifier substrate 134, whereby the output end of the coil 135 provided on the antenna substrate 130 and the amplifier substrate are connected. The AM / FM reception signal received by the antenna element constituted by the antenna pattern and the top portion 131 is connected to the input end of the AM / FM amplifier provided in 134, and the AM / FM amplifier on the amplifier board 134 is connected to the AM / FM amplifier. It will be entered. A collar 145 is fitted to the root of the cable 122 so as to bundle the cables 122 drawn from the drawing holes of the antenna base 120.

A hook 144 is disposed under the amplifier board 134 and is fitted to the antenna base 120. A pair of elongated engaging legs are extended from both side surfaces of the hook 144. When the antenna device 100 is attached to the vehicle, the engagement leg portion is engaged with an edge of an attachment hole formed in the vehicle, and serves to temporarily fix the antenna device 100 to the vehicle body. Accordingly, when the nut 147 is screwed into the bolt portion 121 from the inside of the vehicle without holding the antenna device 100 from the outside of the vehicle body, the antenna device 100 can be screwed without coming out of the mounting hole.
A base pad 124 is fitted on the lower surface of the antenna base 120. A hole portion into which a total of five screw heads can be inserted is formed in the peripheral portion of the base pad 124, and five screws 146 are inserted into the hole portion from below, and the screws 146 are inserted into the antenna base 120. It is inserted into a fitting hole formed in the peripheral edge portion and screwed to the peripheral edge of the lower surface of the antenna case 110. Thereby, the antenna apparatus 100 can be assembled. When the assembled antenna device 100 is attached by aligning the bolt part 121 to the attachment hole formed in the vehicle, the antenna device 100 is temporarily fixed to the attachment hole by the hook 144 as described above. In this state, the antenna device 100 can be attached to the vehicle body by screwing the nut 147 into the bolt part 121 from the inside of the vehicle.

The configuration of the antenna case 110 of the conventional antenna device 100 is shown in FIGS. 44 is a side view showing the configuration of the antenna case 110 in a sectional view, and FIG. 45 is a bottom view showing the configuration of the antenna case 110.
As shown in these drawings, the antenna case 110 is made of a radio wave transmitting synthetic resin and has a streamlined outer shape that becomes thinner toward the tip. In the antenna case 110, there are formed a space in which the antenna substrate 130 erected and the top portion 131 disposed on the antenna substrate 130 can be stored, and a space in which the amplifier substrate 134 can be stored in the horizontal direction. In addition, in order to screw five screws, a total of five screw holes 110c are formed on the lower surface, one at the front and one on each side of the center and one on both sides of the rear. Further, in order to form the screw hole 110c, five bosses 110b bulging around the screw hole 110c are formed. Furthermore, two bosses 110 e for fixing the top part 131 with the two screws 140 are formed in the upper part in the antenna case 110.

  Further, the top portion 131 of the conventional antenna device 100 is formed by processing a metal plate as shown in FIGS. 42 and 43, and has a top portion that is a curved surface that gently descends toward the front, A first side and a second side that are inclined from the top to both sides are formed. Three slits are formed in each of the first side portion and the second side portion, and each side portion includes four pieces. A pair of pieces from almost the center of these pieces is a contact piece connected to the connection fitting 136. The contact piece is formed so as to be bent substantially vertically from the middle so as not to contact the boss 110b formed so as to bulge inward. In addition, two flat portions are formed on the top portion of the top portion 131, and screw holes are formed in the flat portions, respectively. A screw 140 is inserted into each of the screw holes and screwed into a boss 110e formed on the inner side of the top of the antenna case 110, whereby the top portion 131 is attached to the antenna case 110.

Next, the configuration of the antenna base 120 of the conventional antenna device 100 is shown in FIGS. 46 is a plan view showing the configuration of the antenna base 120, and FIG. 47 is a side view showing the configuration of the antenna base 120.
The antenna base 120 shown in these drawings is made of metal and has a main body portion 120a made of a substantially rectangular flat plate whose front portion is tapered, and a total of five insertion holes are formed in the peripheral portion of the main body portion 120a. 120f is formed. The antenna base 120 is fitted to the antenna case 110 by screwing screws 146 respectively inserted into the fitting holes 120f from below into screw holes 110c formed on the lower surface of the antenna case 110. Three bosses 120e are formed in the tapered front portion of the main body 120a, and an amplifier board 134 is placed on the boss 120e and screws 142 inserted through the amplifier board 134 are respectively connected to the bosses 120e. The amplifier board 134 can be fixed onto the antenna base 120 by being screwed to the antenna base 120.

  In addition, two screw portions 120d are formed in the horizontal direction at substantially the center portion and the rear portion side of the main body portion 120a. The antenna board 130 can be erected and attached to the antenna base 120 by screwing screws 141 inserted through the mounting holes of the antenna board 130 into the screw portions 120d. A rectangular frame-shaped GPS antenna mounting portion 120b that forms a rectangular recess is formed slightly rearward from the center of the main body 120a, and screw holes 120c are formed at the four corners of the GPS antenna mounting portion 120b. The GPS antenna 132 can be attached to the GPS antenna attachment portion 120b by screwing the four screws inserted into the attachment holes of the GPS antenna 132 into the screw holes 120c. A rectangular cable lead hole 120h is formed at the center of the main body 120a. The cable 122 connected to the amplifier board 134 and the cable connected to the GPS antenna 132 can be pulled out from the cable drawing hole 120h.

  Furthermore, four first rectangular holes 120g and two second rectangular holes 120i are formed slightly forward from the center of the main body 120a. The four fitting legs 144b of the hook 144 are respectively inserted into the first rectangular holes 120g, and the hooks 144 are attached to the antenna base 120 by engaging the tips of the first rectangular holes 120g with the back surface of the antenna base 120. The two engagement legs 144c of the hook 144 are inserted into the second rectangular hole 120i and protrude along the bolt part 121 from the lower surface of the antenna base 120. A bolt part 121 is formed so as to protrude from the back surface of the main body part 120a, and a collar 145 for bundling the cable 122 drawn from the cable lead hole 120h is provided.

Next, the structure of the base pad 124 of the conventional antenna device 100 is shown in FIGS. 48 is a plan view showing the configuration of the base pad 124, and FIG. 49 is a side view showing the configuration of the base pad 124.
The base pad 124 shown in these figures is made of rubber or elastomer, and has a curved surface that gradually becomes thinner toward the front part, and is formed of a flat plate that is semi-half-shaped in the shape of an elongated ellipse whose rear end is linear. A main body part 124a is provided, and a peripheral wall part 124b having a shape along the outer shape of the antenna base 120 is formed on the surface of the main body part 124a. The base pad 124 is fitted to the antenna base 120 by placing the antenna base 120 on the surface of the base pad 124 and fitting the antenna base 120 into the peripheral wall portion 124b. Further, a total of five holes 124d are formed along the inner side of the peripheral wall portion 124b, and the heads of screws 146 inserted from below into the insertion holes 120f of the antenna base 120 are inserted into the holes 124d. The An elliptical cutout 124c is formed from the center to the front of the main body 124a, and the bolt 121, the cable 122, and the collar 145 provided on the lower surface of the antenna base 120 protrude from the cutout 124c. become.
Patent Document 2 discloses an antenna device in which a flat antenna element is fixed to an antenna cover, and a short-axis coil antenna element is connected and connected to the flat antenna element by soldering.
Further, in Patent Document 3, a coil element is erected vertically on an antenna base plate, and a capacitor plate formed in a meander shape or the like is connected to the tip of the coil element, and is arranged below the capacitor plate. An antenna device that prevents gain reduction of a flat antenna is disclosed.

JP 2010-21856 A JP 2012-15836 A JP 2012-34226 A

  In the conventional antenna device 100, in order to protect the functional components that receive radio waves from rain and dust, these receiving functional components are housed in the antenna case 110, and the antenna base 120 is fixed to the antenna case 110 with screws 146. ing. In order to prevent rainwater and the like from entering the antenna case 110 from the gap between the antenna case 110 and the antenna base 120, a peripheral wall portion 110d that functions as a waterproof rib is provided at the lower portion of the antenna case 110. A base pad 124 is sandwiched between the peripheral wall portion 110d and the antenna base 120 to form a watertight structure, and the internal functional components are protected. The antenna base 120 is a strength member that holds the functional component and the antenna case 110 and also serves as a ground electrode of the amplifier board 134. The ground of the amplifier board 134 is connected to the vehicle body via the bolt portion 121 and the nut 147 of the antenna base 120. Is electrically connected.

  The sensitivity of the conventional antenna device 100 is determined by the distance between the top portion 131 and the opposing electrical ground plane. It is known that the greater the distance, the better the sensitivity and the greater the area of the top portion 131. For this reason, in order to ensure reception performance, it is necessary to dispose the top portion 131 at a high position or widen the width to increase the area. However, in order to fix the antenna base 120 to the antenna case 110 with the screws 146, a plurality of bosses 110b for forming the screw holes 110c are formed inside the antenna case 110. Since the boss 110b is formed to bulge inwardly, the width of the top portion 131 is restricted in order to avoid interference between the boss 110b and the top portion 131. Therefore, three slits are formed on the side portion of the top portion 131 to narrow the width of the side portion of the top portion 131 at a position facing the boss 110b. Further, the external projection of the automobile is regulated to be 70 mm or less by law, and the top portion whose height is lowered when the antenna device 100 is miniaturized in order to maintain a certain distance or more between the top portion 131 and the grounding surface. A part of 131 was cut away. For this reason, there is a problem that the shape of the top portion 131 is complicated.

Further, the shape of the base pad 124 is a shape shown in FIG. 48 that bypasses the boss 110b of the antenna case 110 so as to maintain a waterproof structure, and is a complicated shape. Further, the antenna case 110 has a complicated structure due to the boss 110b, the peripheral wall portion 110d, and the reinforcing ribs thereof. Since it is necessary to take a large internal space for accommodating the top portion 131 in order to improve reception sensitivity, the antenna case 110 is designed to have a small thickness. I can't. For this reason, there has been a problem in that when the antenna case 110 is molded, a portion having a complicated structure with a different thickness is likely to cause a large shrinkage deformation, and the appearance is often distorted.
Furthermore, since the maximum height of the antenna device 100 is set to a limit height for improving reception sensitivity, the thickness of the antenna base 120 facing the top portion 131 is made thin for further improvement of sensitivity. Becomes effective. However, the antenna base 120 is a strength member that also serves as a ground electrode, and it is necessary to sandwich the base pad 124 between the antenna case 110 and the antenna case 110 with a large axial force in order to prevent water from entering the antenna case 110. There is a problem that it cannot be thinned and becomes large.

When the antenna base 120 becomes large, the base pad 124 that covers a portion of the antenna base 120 exposed to the outside air in order to prevent corrosion due to rainwater or the like also becomes large. For this reason, the roof of a vehicle having a thin plate thickness and low rigidity is pressed by the large base pad 124, and the roof is liable to be distorted by the pressing force, thereby deteriorating the appearance design and reducing the waterproof function. There was a problem of doing.
In Patent Document 2 and Patent Document 3, since the short-axis coil antenna element and the coil element are connected to the planar antenna element and the capacitor plate so as to hang, the reception performance may not be stabilized due to vibration or the like. It was.
Therefore, an object of the present invention is to provide an antenna device that can solve the above-described problems.

  In order to achieve the above object, an antenna device according to the present invention includes an insulating antenna case having a lower surface opened and a storage space formed therein, an antenna base on which the antenna case is fitted, and the antenna An insulative element holder provided upright on the base, an umbrella-type element installed so as to be positioned at the upper center of the element holder and at substantially the center of the left and right, and amplifying the reception signal of the umbrella-type element A coil having an amplifier and resonating the umbrella-shaped element inserted between the amplifier board placed on the antenna base, the umbrella-shaped element, and the input end of the amplifier at a predetermined frequency. The main feature is that the coil is fixed to the element holder.

In the antenna device of the present invention, the lower surface of the antenna case has a waterproof structure by fitting the antenna base. For this reason, a large base pad for a waterproof structure can be eliminated, and the antenna base does not need to be clamped with a large axial force, so the antenna base should be a metal strength member It can be configured with an insulating base. Further, when the antenna device is attached to the vehicle, the roof is not distorted, and it is possible to prevent the appearance design from being damaged and the waterproof function from being deteriorated. Furthermore, it is not necessary to provide a boss for forming a screw hole for fixing the antenna base with a screw in the antenna case. As a result, the antenna case can be made to have a substantially uniform thin thickness, so that shrinkage deformation at the time of molding hardly occurs and it is possible to prevent the occurrence of sink marks that distort the appearance. Moreover, since the boss is not provided in the antenna case, the configuration of the umbrella-type element can be simplified.
Furthermore, by installing the umbrella-shaped element so as to be positioned at the upper center of the element holder and at substantially the center of the left and right, and fixing the coil that resonates the umbrella-shaped element to a predetermined frequency, the reception performance is maintained at the same level. Thus, the width of the umbrella-shaped element can be narrowed, and the design width can be improved by narrowing the width of the upper portion of the antenna case.

It is a perspective view which shows the structure of the antenna apparatus concerning the Example of this invention. It is a side view which shows the structure of the antenna apparatus concerning the Example of this invention. It is a top view which shows the structure of the antenna apparatus concerning the Example of this invention. It is a front view which shows the structure of the antenna apparatus concerning the Example of this invention. It is a side view which shows the internal structure of the antenna device concerning the Example of this invention with sectional drawing. It is a perspective view which shows the internal structure of the antenna apparatus concerning the Example of this invention with a half cross-sectional view. It is a figure which shows the state which fits an antenna case in the antenna assembly concerning the antenna apparatus of this invention. It is a perspective view which shows the structure of the antenna assembly concerning the antenna apparatus of this invention. It is a top view which shows the structure of the antenna assembly concerning the antenna apparatus of this invention. It is a side view which shows the structure of the antenna assembly concerning the antenna apparatus of this invention. It is a front view which shows the structure of the antenna assembly concerning the antenna apparatus of this invention. It is a side view which shows the structure of the antenna case concerning the antenna apparatus of this invention. It is a bottom view which shows the structure of the antenna case concerning the antenna apparatus of this invention. It is a side view which shows the structure of the antenna case concerning the antenna apparatus of this invention with sectional drawing. It is a front view which shows the structure of the antenna case concerning the antenna apparatus of this invention with sectional drawing. It is a top view which shows the structure of the insulation base concerning the antenna apparatus of this invention. It is a side view which shows the structure of the insulation base concerning the antenna apparatus of this invention. It is a bottom view which shows the structure of the insulation base concerning the antenna apparatus of this invention. It is a top view which shows the structure of the electroconductive base concerning the antenna apparatus of this invention. It is a side view which shows the structure of the electroconductive base concerning the antenna apparatus of this invention. It is a bottom view which shows the structure of the electroconductive base concerning the antenna apparatus of this invention. It is a perspective view which shows the structure of the assembly of the antenna base concerning the antenna apparatus of this invention. It is a perspective view which shows the structure of the antenna base concerning the antenna apparatus of this invention. It is a bottom view which shows the structure of the antenna base concerning the antenna apparatus of this invention. It is a front view which shows the structure of the antenna base concerning the antenna apparatus of this invention. It is a front view which shows the structure of the antenna base concerning the antenna apparatus of this invention with sectional drawing. It is a perspective view which shows the structure of the element holder concerning the antenna apparatus of this invention. It is a side view which shows the structure of the element holder concerning the antenna apparatus of this invention. It is a top view which shows the structure of the element holder concerning the antenna apparatus of this invention. It is a front view which shows the structure of the element holder concerning the antenna apparatus of this invention. It is a side view which shows the structure of the element holder concerning the antenna apparatus of this invention with sectional drawing. It is a top view which shows the structure of the umbrella-type element concerning the antenna apparatus of this invention. It is a perspective view which shows the aspect which assembles | attaches the umbrella-shaped element concerning the antenna apparatus of this invention to an element holder. It is a side view which shows the structure which assembled | attached the umbrella-shaped element concerning the antenna apparatus of this invention to the element holder. It is a front view which shows the partial structure which assembled | attached the umbrella-shaped element concerning the antenna apparatus of this invention to the element holder with sectional drawing. It is a perspective view which shows the structure of the antenna board | substrate concerning the antenna apparatus of this invention. It is the perspective view and top view which show the structure of the coil concerning the antenna apparatus of this invention. It is a perspective view which shows the structure of the electric power feeding terminal concerning the antenna apparatus of this invention. It is a perspective view which shows the assembly of the umbrella-type element concerning the antenna apparatus of this invention, an element holder, a ring-shaped pad, and a skimmer cover. It is a graph which shows the frequency characteristic of the average gain of the antenna apparatus of this invention, and the conventional antenna apparatus. It is a side view which shows the structure of the conventional antenna device. It is a side view which shows the internal structure of the conventional antenna device. It is an exploded view showing the configuration of a conventional antenna device. It is a side view which shows the structure of the antenna case of the conventional antenna device with sectional drawing. It is a bottom view which shows the structure of the antenna case of the conventional antenna device. It is a top view which shows the structure of the antenna base of the conventional antenna apparatus. It is a side view which shows the structure of the antenna base of the conventional antenna apparatus. It is a top view which shows the structure of the base pad of the conventional antenna device. It is a side view which shows the structure of the base pad of the conventional antenna apparatus.

The configuration of an antenna device 1 according to an embodiment of the present invention is shown in FIGS. However, FIG. 1 is a perspective view showing the configuration of the antenna device 1 according to the present invention, FIG. 2 is a side view showing the configuration of the antenna device 1 according to the present invention, and FIG. 3 is the antenna device 1 according to the present invention. FIG. 4 is a front view showing the configuration of the antenna device 1 according to the present invention.
As shown in these drawings, an antenna device 1 according to an embodiment of the present invention is an antenna device that is attached to a roof of a vehicle, and includes an antenna case 10 having an antenna base 11 fitted to the lower surface. . The antenna case 10 is made of a radio wave permeable synthetic resin, and has a streamlined outer shape (referred to as a “shark fin shape”) that becomes thinner toward the tip and has a curved side surface that is narrowed inward. . An antenna assembly described later is housed in an antenna case 10 in which the antenna base 11 is fitted to the lower surface. From the lower surface of the antenna base 11, a bolt part 21a for attaching the antenna device 1 to the vehicle body is formed so as to protrude. The antenna device 1 is a small and low-profile antenna device having a length of about 151 mm, a width of about 63 mm, and a height of about 66 mm, and is capable of receiving AM broadcast and FM broadcast.

The internal configuration of the antenna device 1 according to the embodiment of the present invention is shown in FIGS. However, FIG. 5 is a side view showing the internal configuration of the antenna device 1 according to the present invention in an AA sectional view, and FIG. 6 is a perspective view showing the internal configuration of the antenna device 1 according to the present invention in a half sectional view. is there. In FIG. 6, the coil 14 is omitted.
The antenna device 1 according to the embodiment of the present invention is an antenna device that can receive an AM radio band and an FM radio band of 76 to 90 MHz or 88 to 108 MHz. The antenna device 1 includes a resin antenna case 10 and an antenna base 11 including a resin insulating base 20 and a metal conductive base 21 that are fitted to the lower surface of the antenna case 10. In the antenna base 11, the conductive base 21 is slightly smaller than the insulating base 20 and has a shorter length. The conductive base 21 is disposed at a position from the front side on the insulating base 20 to the slightly rear side of the center. The rear end of the conductive base 21 is fixed so as to be slightly movable back and forth. An element holder 12 made of a resin-made rectangular frame is erected and attached from the center to the rear side of the upper surface of the antenna base 11, and the amplifier board 16 is attached almost horizontally on the conductive base 21. ing.

  From the lower surface of the conductive base 21 in the antenna base 11, a bolt portion 21 a for attaching the antenna device 1 to the vehicle is formed so as to protrude. A plurality of cables that output reception signals and the like are led out from the through hole of the bolt portion 21a and the cable outlet formed on the rear side thereof. The element holder 12 is composed of a rectangular frame portion, and a holding portion for supporting the umbrella-shaped element 13 is formed on the upper portion of the frame portion. Further, a coil 14 of about 1 μH to 3 μH, which is connected in series to the umbrella-shaped element 13 and resonates at the FM frequency, is held inside the standing frame on the front side of the element holder 12. The lead wire led out from the upper end of the coil 14 is connected to the terminal of the umbrella-shaped element 13, and the lead wire led out from the lower end of the coil 14 is connected to the power supply terminal 15. The power supply terminal 15 is bent as shown in the drawing, and the upper part is fixed to the surface facing the coil 14 of the standing frame on the front side of the element holder 12, and the terminal at the lower end is the input of the amplifier board 16. Connected to the terminal. As a result, the AM / FM reception signal received by the umbrella element 13 to which the coil 14 is connected in series is amplified by the amplifier assembled on the amplifier board 16. The antenna composed of the umbrella element 13 and the coil 14 operates as a non-resonant antenna in the AM radio band.

As shown in FIGS. 5 and 6, an outer peripheral wall portion and an inner peripheral wall portion are formed in the lower portion of the antenna case 10, and the lower end surface of the inner peripheral wall portion is in contact with the upper surface of the outer periphery of the insulating base 20. It becomes like this. The lower end surface of the abutting inner peripheral wall portion and the upper surface of the insulating base 20 are bonded together by welding or applying an adhesive with a laser. Thereby, the inside of the antenna case 10 whose lower surface is closed by the insulating base 20 has a waterproof structure. A skim cover 18 in the form of a rubber or elastomer string is wound around the peripheral side surface of the insulating base 20. Further, a central notch portion through which the bolt portion 21a formed in the conductive base 21 is inserted is formed at the center portion of the insulating base 20, and a ring-shaped seal 17 having a waterproof structure inside the center notch portion is provided. The insulating base 20 is fitted into an annular portion formed on the lower surface so as to surround the central notch.
FIG. 7 shows a state where the antenna case 10 is fitted to the antenna assembly 2 according to the antenna device 1 of the present invention. When the inner peripheral wall portion of the antenna case 10 is fitted to the insulating base 20 of the antenna base 11 from the state shown in FIG. 7, the state shown in FIGS. The antenna assembly 2 includes an element holder 12 assembled on an antenna base 11 including an insulating base 20 and a conductive base 21, an umbrella element 13, a coil 14, a feeding terminal 15, and an amplifier board 16. Has been.

Next, the structure of the antenna assembly 2 according to the antenna device 1 of the present invention is shown in FIGS. 8 is a perspective view showing the configuration of the antenna assembly 2 according to the antenna device 1 of the present invention, and FIG. 9 is a top view showing the configuration of the antenna assembly 2 according to the antenna device 1 of the present invention. FIG. 11 is a side view showing the configuration of the antenna assembly 2 according to the antenna device 1 of the present invention, and FIG. 11 is a front view showing the configuration of the antenna assembly 2 according to the antenna device 1 of the present invention.
The antenna assembly 2 includes an antenna base 11 including an insulating base 20 and a conductive base 21. On the antenna base 11, an element holder 12, an umbrella element 13, a coil 14, a feeding terminal 15, and an amplifier board 16 are provided. And are assembled. First, the configuration of the antenna base 11 including the insulating base 20 and the conductive base 21 will be described. First, the structure of the insulating base 20 will be described. A top view showing the structure of the insulating base 20 is shown in FIG. 16, a side view showing the structure of the insulating base 20 is shown in FIG. The figure is shown in FIG.

  The insulating base 20 shown in these drawings is a molded product of a synthetic resin, and is composed of a main body portion 20a having a shape in which the width gradually decreases toward the front side and the front end and the rear end are rounded. A peripheral wall portion 20c having a predetermined height is formed along the outer peripheral edge so as to protrude slightly inward from the outer peripheral edge. Further, on the upper surface of the main body portion 20a, an engagement boss portion 20d is formed at the approximate center of the front side. The engagement boss portion 20d is substantially cylindrical, has three slits formed in the vertical direction, and has an engagement portion that protrudes in a wedge shape outside the tip, and has elasticity in the radial direction. A substantially oval central cutout 20f is formed at the center of the main body 20a, and a pair of plate-like engagement pieces 20e are formed on the rear side of the central cutout 20f. A wedge-shaped engaging portion is formed on the outer side surface of the tip of the pair of engaging pieces 20e. A storage portion 20j having a U-shaped cross-sectional shape is formed on the inner side of the rear portion of the peripheral wall portion 20c of the main body portion 20a, and a pair of small engaging protrusions 20g are formed outward at the rear end of the main body portion 20a. Is formed. An annular groove 20h is formed on the lower surface of the main body 20a so as to surround the central notch 20f. The annular groove 20h is a groove into which the ring-shaped seal 17 is inserted, and a plurality of pressing pieces 20i are formed protruding inward from the upper end of the annular groove 20h so that the inserted ring-shaped seal 17 does not come out.

Next, a top view showing the configuration of the conductive base 21 is shown in FIG. 19, a side view showing the configuration of the conductive base 21 is shown in FIG. 20, and a bottom view showing the configuration of the conductive base 21 is shown in FIG.
The conductive base 21 shown in these drawings is made of metal, and has a similar shape slightly smaller than the inner peripheral shape of the peripheral wall portion 20c so as to be housed inside the peripheral wall portion 20c of the insulating base 20. However, the conductive base 21 is formed short so that the rear end is located on the rear side of the engagement piece 20e formed on the insulating base 20. On the upper surface of the conductive base 21, there are formed three second bosses 21h having a circular engaging hole 21d formed at the front end and screw holes formed on both the rear side and the substantially central side. The second bosses 21h are respectively formed at the vertices of an isosceles triangle, and are bosses into which screws inserted through the amplifier board 16 are screwed.

Here, a perspective view showing the configuration of the amplifier substrate 16 is shown in FIG. As shown in this figure, the amplifier board 16 is composed of a board body 16a that gradually decreases in width from the rear part to the front part, and through holes 16b are formed at substantially the center of the front part and both sides of the rear part. The insertion holes 16b are formed at the vertices of an isosceles triangle, and the amplifier board 16 is fixed to the conductive base 21 by screwing the screws inserted through the insertion holes 16b into the three second bosses 21h. The Further, a connection hole 16c is formed in the rear part of the substrate body 16a, and the connection hole 16c is electrically connected to an input terminal of an amplifier assembled in the amplifier substrate 16.
Returning to FIGS. 19 to 21, a pair of first bosses 21 g are formed on both sides slightly behind the center of the upper surface of the conductive base 21. Further, a rectangular locking hole 21f is formed in the approximate center of the rear end of the upper surface, and a pair of plate-like standing pieces 21j are formed on both sides of the locking hole 21f substantially parallel to the long axis. Further, a bolt part 21a is formed to protrude from the center of the lower surface of the main body part 21b to the rear part. An insertion hole 21e is formed in the bolt part 21a, and a notch 21i is formed on a side surface of the bolt part 21a. The cable led out from the amplifier board 16 is inserted from above into the insertion hole 21e of the bolt part 21a and can be led out from the notch 21i below the insertion hole 21e.

Next, the configuration of the antenna base 11 including the insulating base 20 and the conductive base 21 is shown in FIGS. However, FIG. 22 is a perspective view illustrating the configuration of the antenna base 11, FIG. 23 is a perspective view illustrating the configuration of the assembled antenna base 11, and FIG. 24 illustrates the configuration of the assembled antenna base 11. FIG. 25 is a front view showing the configuration of the assembled antenna base 11, and FIG. 26 is a front view showing the configuration of the assembled antenna base 11 in a DD sectional view.
As shown in FIG. 22, the conductive base 21 is disposed on the insulating base 20, and then the conductive base 21 is placed on the insulating base 20. Then, the engaging boss portion 20 d of the insulating base 20 is fitted into the engaging hole 21 d of the conductive base 21, and the pair of engaging pieces 20 e of the insulating base 20 are inserted into the locking holes 21 f of the conductive base 21. As a result, the engaging portion at the tip of the engaging boss portion 20d is locked around the upper end of the engaging hole 21d, and the engaging portion formed at the tip of the engaging piece 20e is The conductive base 21 is fixed so as not to come out of the insulating base 20 by engaging with the upper surface of the installation piece 21j. The first engaging portion where the engaging boss portion 20d engages with the engaging hole 21d is an engaging portion for positioning, and the second engaging portion where the engaging piece 20e engages with the standing piece 21j is The engaging portion is slidable in the longitudinal axis direction. As a result, even if the relative lengths of the conductive base 21 and the insulating base 20 change due to the difference in thermal expansion coefficient, the difference in length can be absorbed by the second engaging portion. The configuration of the antenna base 11 in which the conductive base 21 is fixed on the insulating base 20 is shown in FIGS.

Here, the structure of the antenna case 10 according to the antenna device 1 of the present invention is shown in FIGS. 12 is a side view showing the configuration of the antenna case 10 according to the antenna device 1 of the present invention, and FIG. 13 is a bottom view showing the configuration of the antenna case 10 according to the antenna device 1 of the present invention. FIG. 15 is a side view showing a configuration of the antenna case 10 according to the antenna device 1 of the present invention in a B-B cross-sectional view, and FIG. FIG.
As shown in these drawings, the antenna case 10 is made of a radio wave-transmitting synthetic resin, and becomes thinner as it goes to the tip, and has a shark fin shape with a curved surface narrowed to the inside. It is formed by a thin outer shell portion 10a. A thin peripheral wall portion having a small thickness is formed at the lower portion of the antenna case 10. An outer peripheral wall portion 10b is formed on the outer side, and an inner peripheral wall portion 10c is formed on the inner side. When the antenna case 10 is fitted to the antenna assembly 2, the inner peripheral wall portion 10 c is fitted to the outer periphery of the peripheral wall portion 20 c formed on the upper surface of the synthetic resin insulating base 20 in the antenna base 11, and the inner peripheral wall The lower end surface of the portion 10 c comes into contact with the upper surface of the insulating base 20. The abutted portion is irradiated with a laser to be welded or applied with an adhesive and bonded. Thereby, the antenna assembly 2 is housed in a waterproof structure including the antenna case 10 and the insulating base 20.
As described above, since the lower end surface of the antenna case 10 is fixed to the insulating base 20 by welding or adhesion, it is necessary to provide the antenna case 10 with a boss that forms a screw hole for fixing the antenna base 11 with a screw. There is no. As a result, the antenna case 10 can be formed into a substantially uniform thin outer shell portion 10a, so that it is possible to prevent shrinkage deformation during molding and to prevent sink marks that are distorted in appearance.

Next, the configuration of the element holder 12 according to the antenna device 1 of the present invention is shown in FIGS. 27 is a perspective view showing the configuration of the element holder 12 according to the antenna device 1 of the present invention, and FIG. 28 is a side view showing the configuration of the element holder 12 according to the antenna device 1 of the present invention. FIG. 30 is a top view showing the configuration of the element holder 12 according to the antenna device 1 of the present invention, FIG. 30 is a front view showing the configuration of the element holder 12 according to the antenna device 1 of the present invention, and FIG. It is a front view which shows the structure of the element holder 12 concerning the antenna apparatus 1 by EE sectional drawing.
The element holder 12 shown in these drawings is composed of a rectangular frame portion 12a, and a first clamping portion 12c and a second clamping portion 12d that support the umbrella-shaped element 13 are opposed to each other on the upper portion of the frame portion 12a. It is formed to do. Moreover, the cross-sectional shape of the frame part 12a is also rectangular. A foot 12b extending in the lateral direction is formed at the lower end on the front side of the element holder 12, and through holes 12j are formed at both ends of the foot 12b. The screws inserted through the insertion holes 12j are screwed to the pair of first bosses 21g formed on the conductive base 21. Further, an L-shaped engagement claw 12e is formed to project from the lower end of the rear side of the element holder 12. The engaging claws 12e are accommodated in a storage portion 20j having a U-shaped cross section formed on the insulating base 20 so as not to come out.

  The first clamping part 12c is formed in a substantially U shape with respect to the second clamping part 12d, and the first clamping part 12c is formed higher than the second clamping part 12d. A wedge-shaped engagement protrusion 12h is formed at substantially the center of the surface of the second clamping portion 12d that faces the first clamping portion 12c. A folded portion formed in the major axis direction inside the umbrella-shaped element 13 is fitted into the gap between the first sandwiching portion 12c and the second sandwiching portion 12d. When the folded portion is inserted, the engagement protrusion 12h is engaged with an engagement window formed in the folded portion. As a result, the umbrella-shaped element 13 can be supported by the element holder 12 so as not to come out of the first clamping part 12c and the second clamping part 12d. Further, the terminal provided at the lower end of the umbrella-shaped element 13 is held by the rounded L-shaped terminal holding portion 12k. The terminal holding portion 12k is formed on the outer surface of the front frame portion 12a in the element holder 12. Furthermore, four coil holding pieces 12f for holding the coil 14 are formed vertically and horizontally inside the front frame portion 12a of the element holder 12. A terminal holding piece 12 i for holding the power supply terminal 15 is formed on the outer surface of the front frame portion 12 a of the element holder 12.

Next, a bottom view showing the configuration of the umbrella element 13 is shown in FIG. 32, a perspective view showing the manner in which the umbrella element 13 and the coil 14 are assembled to the element holder 12 is shown in FIG. FIG. 34 shows a side view showing a mode assembled to the element holder 12, and FIG. 35 shows a front view showing a mode where the umbrella element 13 is assembled to the element holder 12 in a sectional view taken along line FF.
As shown in these drawings, the umbrella-shaped element 13 has a flat top portion 13a, and a roof-like inclined portion that is inclined to both sides from the top portion 13a is formed. Only one slit 13d is formed at substantially the center of the inclined portion, and the front side of the slit 13d is a first inclined portion 13b, and the rear side of the slit 13d is a second inclined portion 13c. Moreover, a pair of back surface parts 13e which bent the side edge of the rear end of the 2nd inclination part 13c are formed. The inclination angle of the top portion 13a where the first inclined portion 13b is formed is larger than the inclination angle of the top portion 13a where the second inclined portion 13c is formed. The umbrella element 13 is formed by bending a thin metal plate cut out in a predetermined shape, and a folded portion 13f extending downward from the center of the top portion 13b is formed. A terminal 13g is formed laterally from the folded portion 13f, and an engagement window is formed in the folded portion 13f inside the second inclined portion 13c so that the engagement protrusion 12h of the element holder 12 can be engaged. .
In the antenna device 1 according to the present invention, since the antenna case 10 is not provided with a boss, it is not necessary to prevent interference between the umbrella-shaped element 13 and the boss, and the shape of the umbrella-shaped element 13 is simplified. be able to.

Here, a perspective view showing the configuration of the coil 14 is shown in FIG. 37A, and a top view showing the configuration of the coil is shown in FIG. 37B. As shown in these drawings, the coil 14 has a coil body 14a wound in a cylindrical shape, a lead 14b led out tangentially from the upper end of the coil body 14a, and led out tangentially from the lower end of the coil body 14a. Lead 14b. Thus, the interval between the two leads 14b is substantially equal to the diameter of the coil body 14a. The coil 14 is a coil of about 1 μH to 3 μH that is connected in series to the umbrella-shaped element 13 and resonates at the FM frequency.
FIG. 38 is a perspective view showing the configuration of the power supply terminal 15. As shown in this figure, a rectangular planar portion 15a is formed at the end of the power supply terminal 15, and a bent portion 15b is formed at one end edge thereof. The planar portion 15a is positioned and held by the terminal holding piece 12i of the element holder 12 by the bent portion 15b, and the hole formed in the planar portion 15a coincides with the lead-out groove 12g when held. To come. A bent lead-out portion 15c is formed by extending from the other end edge of the planar portion 15a, and a terminal piece 15d is formed at the tip of the lead-out portion 15c. The terminal piece 15d is inserted into the connection hole 16c of the amplifier board 16 and soldered, and is connected to the input terminal of the amplifier.

  As shown in FIG. 33, the umbrella-shaped element 13 disposed on the element holder 12 is moved downward, and the folded portion 13f is inserted into the gap between the first sandwiching portion 12c and the second sandwiching portion 12d. Let When the folded portion 13f is pushed into the gap, as shown in FIG. 35, the wedge-shaped engagement protrusion 12h formed on the inner side of the second sandwiching portion 12d is formed in the engagement window formed on the folded portion 13f. The umbrella-shaped element 13 comes to be fixed to the element holder 12. At this time, the terminal 13g formed in the folded portion 13f is held in the terminal holding portion 12k of the element holder 12. Next, the coil 14 shown in FIG. 33 is inserted into the holding space surrounded by the four coil holding pieces 12f. Thus, the coil 14 is held by the four coil holding pieces 12f. The lead 14b from the upper end of the coil 14 is led out from a lead-out groove 12g formed in the terminal holding portion 12k, and is inserted into the hole of the terminal 13g of the umbrella element 13 held in the terminal holding portion 12k. The terminal 13g is connected by soldering. Further, the lead 14b from the lower end of the coil 14 is led out from the lead-out groove 12g formed between the terminal holding pieces 12i and inserted into the hole of the power supply terminal 15 held by the terminal holding pieces 12i. And connected to the power supply terminal 15 by soldering. As a result, the coil 14 is disposed substantially at the center in the width direction of the element holder 12. That is, since the coil 14 is arranged at the substantially center in the width direction of the umbrella-shaped element 13, interference between the umbrella-shaped element 13 and the coil 14 can be avoided as much as possible, and the reception performance is maintained at the same level. Thus, the width of the umbrella element 13 can be reduced. Thereby, the width | variety of the upper part of the antenna case 10 can be narrowed, and the designability can be improved.

Next, FIG. 39 shows a perspective view showing the assembly of the umbrella-shaped element 13, the element holder 12, the ring-shaped seal 17 and the gap cover 18 according to the antenna device 1 of the present invention.
As shown in this figure, the conductive base 21 is disposed on the insulating base 20, and then the conductive base 21 is placed on the insulating base 20. Then, the engaging boss portion 20 d of the insulating base 20 is fitted into the engaging hole 21 d of the conductive base 21, and the pair of engaging pieces 20 e of the insulating base 20 are inserted into the locking holes 21 f of the conductive base 21. As a result, the engaging portion at the tip of the engaging boss portion 20d fitted around the upper end of the engaging hole 21d is locked, and the engaging portion formed at the tip of the engaging piece 20e becomes the conductive base. The conductive base 21 is fixed so as not to come out of the insulating base 20 by engaging with the upper surface of the standing piece 21j. At this time, the bolt portion 21 a formed to protrude from the lower surface of the conductive base 21 passes through the central notch portion 20 f of the insulating base 20 and protrudes from the lower surface of the insulating base 20.

Next, the ring-shaped seal 17 is fitted into an annular groove 20h shown in FIG. 24 formed around the central notch 20f on the lower surface of the insulating base 20. A pressing piece 20i formed on the outer peripheral edge of the annular groove 20h is brought into contact with the flat upper surface of the ring-shaped seal 17, so that the ring-shaped seal 17 is held in the annular groove 20h. Further, the clearance cover 18 is formed in a string shape, and both end portions are cut portions 18b. A hole is formed slightly inside the cut portion 18b, and one of the engagement protrusions 20g formed at the rear end of the insulating base 20 is inserted into the hole, and the peripheral side surface of the insulating base 20 is inserted. The skimmer cover 18 is wound around the peripheral side surface of the insulating base 20 while the formed flange portion 20b is inserted into the groove portion 18a of the skimmer cover 18. Then, a hole formed slightly inside the cut end 18b at the winding end is inserted into the other engagement protrusion 20g. Thereby, the clearance cover 18 can be attached to the peripheral side surface of the insulating base 20.
In the conventional antenna device, as a rigid structure composed of an antenna case and an antenna base, a waterproof structure is formed by sandwiching a base pad with a large axial force. In the antenna device 1 of the present invention, since the antenna case 10 and the insulating base 20 are welded or bonded to form a waterproof structure, there is no need to use the conductive base 21 as a strength member, and the size of the conductive base 21 is reduced to a ring. The size can be reduced to a size as long as the seal 17 can be pressed. The conductive base 21 also functions as a ground for the amplifier board 16.

Returning to the description of the antenna assembly 2, the configuration of each part constituting the antenna assembly 2 is as described above. In the antenna assembly 2 shown in FIGS. 8 to 11, a skimmer cover 18 is attached to the outer periphery of the antenna base 11 including an insulating base 20 having a conductive base 21 assembled on the upper surface. An element holder 12 is erected and fixed on the antenna base 11, and an amplifier board 16 is fixed substantially horizontally. An umbrella-shaped element 13 is attached to the upper part of the element holder 12, and a coil 14 is held inside the frame portion 12 a of the element holder 12. The upper lead of the coil 14 is connected to the terminal 13 f of the umbrella element 13, and the lower lead of the coil 14 is connected to one end of the power supply terminal 15. The other end of the power supply terminal 15 is connected to the input terminal of the amplifier of the amplifier board 16 so that the reception signal of the antenna composed of the umbrella element 13 and the coil 14 is amplified by the amplifier of the amplifier board 16.
In the antenna assembly 2, the first inclined portion 13 b of the umbrella-shaped element 13 is located on the conductive base 21, and the height of the first inclined portion 13 b from the ground plane corresponds to the height from the conductive base 21. Further, the second inclined portion 13c of the umbrella-shaped element 13 is positioned substantially on the insulating base 20, and the height from the ground surface of the second inclined portion 13c is the height from the vehicle body to which the antenna device 1 is attached. This is essentially equivalent. Thus, even if the height of the antenna device 1 is lowered, the substantial height from the ground plane of the second inclined portion 13c can be increased, and the operation gain of the antenna device 1 is improved by increasing the height. Will be able to.

The frequency characteristics of the average gain according to the antenna device 1 of the present invention are shown in FIG. 40 in comparison with the frequency characteristics of the average gain according to the conventional antenna device. The average gain is an average gain with an elevation angle of 45 °.
In the antenna device 1 of the present invention, the height is about 66 mm, the width is about 63 mm, and the length is about 151 mm. In the conventional antenna device, the height is about 66 mm, the width is about 63 mm, and the length is about 153 mm. Thus, both antenna devices are approximately the same size. Referring to FIG. 40, in antenna apparatus 1 of the present invention, a maximum gain of about −28 dBd is obtained at a frequency of about 84 MHz, and an average gain of about −34 dBd or more is obtained in a frequency band of 76 MHz to 90 MHz. On the other hand, in the conventional antenna device, a maximum gain of about −28.5 dBd is obtained at a frequency of about 84 MHz, and an average gain of about −35 dBd or more is obtained in a frequency band of 76 MHz to 90 MHz. Thus, it can be seen that the gain of the antenna device 1 of the present invention is improved over the entire frequency band of 76 MHz to 90 MHz.

  In the antenna device 1 according to the present invention described above, temporary fixing hooks for temporary fixing in which a pair of elongated engaging leg portions are extended from both side surfaces into the through holes of the bolt portions 21a of the conductive base 21 are fitted. You may do it. When the antenna device 1 is attached to the vehicle, the engagement leg portion is engaged with an edge of an attachment hole formed in the vehicle, so that the antenna device 1 is temporarily fixed to the vehicle body. In addition, when the hook is fitted in the through hole, the cable cannot be led out through the through hole, but the cable connected to the amplifier is led out from the cable outlet formed on the rear side of the through hole. Can do.

DESCRIPTION OF SYMBOLS 1 Antenna apparatus, 2 Antenna assembly, 10 Antenna case, 10a Outer shell part, 10b Outer peripheral wall part, 10c Outer peripheral wall part, 11 Antenna base, 12 Element holder, 12a Frame part, 12b Foot part, 12c Holding part, 12d Holding part 12e engaging claw, 12f coil holding piece, 12g lead-out groove, 12h engaging protrusion, 12i terminal holding piece, 12j insertion hole, 12k terminal holding part, 13 umbrella-shaped element, 13a top part, 13b inclined part, 13b Top, 13c Inclined part, 13d Slit, 13e Rear part, 13f Terminal, 13f Folded part, 13g Terminal, 14 Coil, 14a Coil body, 14b Lead, 15 Power supply terminal, 15a Planar part, 15b Bent part, 15c Derived part 15d terminal strip, 16 amplifier board, 16a board Body, 16b Insertion hole, 16c Connection hole, 17 Ring seal, 18 Clearance cover, 18a Groove part, 18b Cutting part, 20 Insulating base, 20a Main body part, 20b Gutter part, 20c Peripheral wall part, 20d Engagement boss part, 20e Engagement Joint piece, 20f central notch, 20g engagement protrusion, 20h annular groove, 20i holding piece, 20j storage part, 21 conductive base, 21a bolt part, 21b body part, 21d engagement hole, 21e insertion hole, 21f locking hole 21g 1st boss, 21h 2nd boss, 21i notch, 21j standing piece, 100 antenna device, 110 antenna case, 110a outer shell, 110b boss, 110c screw hole, 110d peripheral wall, 110e boss, 120 antenna base, 120a body part, 120b antenna mounting part, 120c screw hole, 120d 120e boss, 120f insertion hole, 120g first rectangular hole, 120h cable outlet hole, 120i second rectangular hole, 121 bolt part, 122 cable, 124 base pad, 124a body part, 124b peripheral wall part, 124c notch hole, 124d hole portion, 130 antenna substrate, 131 top portion, 132 antenna, 133 connection line, 134 amplifier substrate, 135 coil, 136 connection fitting, 140 screw, 141 screw, 142 screw, 143 terminal, 144 hook, 144b fitting leg, 144c Engagement leg, 145 collar, 146 screw, 147 nut

Claims (11)

An insulating antenna case having a lower surface opened and a storage space formed therein;
An antenna base on which the antenna case is fitted;
An insulative element holder provided upright on the antenna base;
An umbrella-shaped element installed so as to be positioned at the upper center of the element holder and at substantially the center of the left and right;
An amplifier that amplifies the received signal of the umbrella-shaped element, and an amplifier substrate placed on the antenna base;
A coil for resonating the umbrella-shaped element inserted between the umbrella-shaped element and the input end of the amplifier at a predetermined frequency, and a coil fixed to the element holder;
An antenna device comprising:   The antenna base includes a resin-made insulating base that is used as a strength member with the antenna case fitted thereon, and a conductive base that is smaller than the insulating base and is fixed to the insulating base. 1. The antenna device according to 1.   The antenna device according to claim 1, wherein the element holder is formed of a frame-shaped frame portion, and the coil is fixed to the inside of the frame portion.   The antenna device according to claim 1, wherein the element holder includes a coil holding piece for holding the coil so that the coil is arranged at substantially the left and right centers of the element holder. The umbrella-shaped element includes a top portion and a roof-like inclined portion that is inclined on both sides from the top portion,
The antenna device according to claim 1, wherein a part of the element holder is disposed between roof-shaped inclined portions inclined on both sides of the umbrella-shaped element.   The antenna apparatus according to claim 1, wherein the umbrella-shaped element and the coil operate as a resonant antenna that resonates in the FM frequency band and operate as a non-resonant antenna in the AM frequency band.   The antenna device according to claim 1, wherein the coil is connected to a front side of the umbrella-type element.   The antenna device according to claim 1, wherein the coil is disposed below a front side of the umbrella-type element.   3. The antenna according to claim 2, wherein when the antenna case is fitted on the insulating base, a lower surface of the antenna case is fixed to the insulating base by welding or adhesion to form a waterproof structure. apparatus.   An engagement piece that is substantially parallel to the long axis is formed on the insulating base, and a standing piece that is engaged with the engagement piece is formed on the conductive base that is substantially parallel to the long axis. 3. The antenna device according to claim 2, wherein the conductive base can be expanded and contracted in a major axis direction with respect to the insulating base in a state where the conductive base is fixed on the insulating base by being engaged with a standing piece. .   In the antenna base, a bolt portion formed so as to protrude from the lower surface of the conductive base protrudes from the lower surface through the insulating base, and is formed on the lower surface of the insulating base so as to surround the bolt portion. The antenna device according to claim 2, wherein a ring-shaped seal is inserted into the groove portion.