JP2011078020A - Antenna for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress influences, caused by noise inside a car, upon an antenna by allowing the antenna to have a ground function, in simple structure. <P>SOLUTION: An antenna for vehicle includes a resin ceiling plate 14, an antenna element 20a and a conductive sheet 30. The antenna element 20a includes a ground plate 22, a conductive radiation plate 21 disposed while being opposed to the ground plate 22, and a conductive connection plate 23 electrically connecting the radiation plate 21 and the ground plate 22. The conductive sheet 30 is larger than the ground plate 22 and is held between the ceiling plate 14 and the ground plate 22 so as to be protruded from the surroundings of the ground plate 22. The antenna element 20a is disposed between a resin-made vehicle roof and the ceiling plate 14. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a structure of a vehicle antenna.

  Many receiving devices such as a radio, a television, and a radio are mounted on the vehicle, and an antenna corresponding to the frequency of each of these receiving devices is provided. Conventionally, a pole antenna or a rod antenna attached to a pillar, fender, or roof of a vehicle body has been used for these antennas (see, for example, Patent Document 1). However, the pole antenna and the rod antenna look good because they protrude outside the vehicle. However, there were problems such as wind noise. Further, in order to suppress the generation of wind noise, a spiral-shaped protrusion may be provided on the surface, but in this case, there is a problem that the appearance is further deteriorated. For this reason, there has been proposed a method for sharing the space and improving the vehicle appearance by installing an antenna in the internal space of a resin exterior such as an air spoiler or a vehicle bumper attached to the vehicle (for example, Patent Document 2).

  Since the pole antenna and the rod antenna are attached to the roof of a metal vehicle or the like, there is no need for a separate ground wire for grounding the antenna to the vehicle. When an antenna is attached inside a resin vehicle exterior product as in the technology, the antenna cannot be grounded to the vehicle only by attaching the antenna element to the vehicle exterior product. For this reason, it is suppressed that antenna performance falls by connecting between the antenna element installed in the exterior goods, and the nearby metal vehicle frame with the grounding member different from a signal wire | line.

JP-A-2005-130130 JP 2009-158990 A

  Incidentally, in recent years, there has been a demand for lighter vehicles in order to further improve fuel efficiency. For this reason, attempts have been made to form vehicle roofs, door exterior panels, and the like using fiber reinforced resin that is lighter than metal. Even when an antenna is mounted inside such a resin-made vehicle exterior plate, it is necessary to connect the antenna and a metal vehicle frame near the antenna by a grounding member, a grounding wire, or the like. There is a problem that it takes. In particular, when the antenna is installed in the space between the exterior plate and the interior plate of the vehicle so that the antenna does not protrude outside the vehicle, it is necessary to route the ground wire in a narrow space because the grounding member cannot be arranged, There was a problem that it took more time to assemble.

  In addition, the pole antenna described in Patent Document 1 and the antenna described in Patent Document 2 are attached to the outside of a metal vehicle exterior plate, and thus were not affected by noise from the vehicle interior. When the antenna is disposed inside the vehicle exterior plate, there is a problem that the antenna is affected by noise in the vehicle interior.

  An object of the present invention is to give an antenna a grounding function with a simple structure. Another object of the present invention is to suppress the influence of noise in the passenger compartment on the antenna with a simple structure.

  The vehicle antenna according to the present invention includes an insulating base portion, a conductive ground plate attached to the base portion, a conductive radiation plate disposed opposite to the ground plate, and the radiation plate and the ground plate. An antenna element including a conductive connection plate for electrical connection, and a conductive thin plate that is larger than the ground plate and sandwiched between the base portion and the ground plate so as to protrude beyond the periphery of the ground plate. It is characterized by providing.

  In the vehicle antenna of the present invention, the base portion is a resin vehicle interior plate, and the antenna element is preferably disposed between the resin vehicle exterior plate and the vehicle interior plate.

  The present invention has an effect that the antenna can have a grounding function with a simple structure. In addition, the present invention has an effect that the influence of noise in the passenger compartment on the antenna can be suppressed with a simple structure.

It is explanatory drawing which shows the state which attached the vehicle antenna in embodiment of this invention to the vehicle. It is a perspective view which shows the structure of the vehicle antenna in embodiment of this invention. It is explanatory drawing which shows the cross section of the center of the vehicle antenna in embodiment shown in FIG. It is a perspective view which shows the structure of the vehicle antenna in other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1A, the vehicle antenna 20 of the present embodiment is attached to the inside of the roof 11 of the vehicle 10 that is a resin vehicle exterior plate, and is configured not to protrude outside the roof 11. Yes. As shown in FIG. 1 (b), the vehicle 10 has a metal frame 13 and an external framework, and a resin roof 11 and a rear window glass 12 are attached to the frame 13. An adhesive is used for attachment. In addition, a resin ceiling plate 14 constituting the ceiling of the vehicle compartment is attached to the vehicle interior side of the frame 13. The ceiling plate 14 is a plate having a shape substantially parallel to the roof 11, and is configured so that a space is formed between the roof 11 and the ceiling plate 14. The vehicle antenna 20 of the present embodiment is mounted on the ceiling plate 14 via a thin conductive sheet 30 and is configured to be disposed in a space between the ceiling plate 14 and the roof 11. A coaxial cable 40 is connected to the vehicle antenna 20 and outputs a radio signal received by the vehicle antenna 20 to the outside. The conductive sheet 30 may be a sheet provided with a conductive function by applying a conductive paint to various plastics, or may be a thin metal foil or a metal plate. As shown in FIG. 1B, the conductive sheet 30 of this embodiment is not electrically connected to the frame 13 of the vehicle 10.

  FIG. 2A to FIG. 2E show the structure of the vehicle antenna 20 of this embodiment. As shown in FIG. 2A, the antenna element 20a is formed by bending a thin metal plate, and is opposed to the ground plate 22 and a rectangular ground plate 22 attached to the resin ceiling plate 14 as a base portion. The rectangular radiation plate 21 is disposed in parallel with the ground plate 22 at intervals, and the connection plate 23 connects between the ground plate 22 and the radiation plate 21. The ground plate 22 and the radiation plate 21 have substantially the same size, and the connection plate 23 connects the central portions of the sides in the longitudinal direction of the plates 21 and 22, and the width thereof is the same as that of the plates 21 and 22. It is shorter than the length in the longitudinal direction. Therefore, the connection plate 23 connects only the vicinity of the center between the radiation plate 21 and the ground plate 22.

  A feeding plate 24 that is bent from the radiation plate 21 toward the ground plate 22 is provided at a position facing the connection plate 23. The front end of the power supply plate 24 is shaped like a triangle toward the ground plate 22, and the front end is a power supply end 28. There is a gap between the power feeding end 28 and the ground plate 22 and they are not in electrical contact. In addition, four square holes 25 are provided in the vicinity of each corner of the ground plate 22, and round holes 26 are provided in the vicinity of each square hole 25. A grounding bracket 27, which is pressed toward the power feeding plate 24 by pressing the grounding plate 22, is provided at a position facing the power feeding end 28 at the tip of the power feeding plate 24. The cross section of the central portion where the connection plate 23 and the feeding plate 24 of the antenna element 20a shown in FIG. 2 (a) are arranged is a gap between the feeding end 28 and the ground plate 22 as shown in FIG. There is a square shape.

  When the antenna element 20a shown in FIG. 2A is formed by pressing or the like, the antenna element 20a is set in a resin mold, and the distance between the radiation plate 21 and the ground plate 22 is made constant by the resin mold. The reinforcing member 29 to be held is insert-molded. As a result, as shown in FIG. 2B, the reinforcing member 29 is formed in a columnar shape between the square holes 25 provided in the vicinity of each corner of the ground plate 22 and the positions facing the square holes 25 of the radiation plate 21. Thus, the antenna element molded product 20b in which the relative positions of the radiation plate 21 and the ground plate 22 are fixed can be obtained.

  As shown in FIG. 2C, the conductive sheet 30 is overlaid on the ceiling plate 14, and as shown in FIG. 2E, the round hole 26 of the ground plate 22 of the antenna element molded product 20b is formed in the ceiling plate 14. When the antenna fixing clip 15 is molded integrally with the antenna 15, the corner of the clip 15 engages with the periphery of the round hole 26, and the antenna element molded product 20 b is electrically conductive between the ground plate 22 and the ceiling plate 14. The sheet 30 is sandwiched and fixed to the ceiling plate 14. The conductive sheet 30 is larger than the ground plate 22 of the antenna element 20 a and is disposed so as to protrude from the periphery of the ground plate 22 in the direction along the surface of the ground plate 22. Further, as shown in FIG. 2D, the core wire 42 of the coaxial cable 40 is connected to the feeding end 28 of the feeding plate 24 by caulking, and the shield wire 41 of the coaxial cable 40 is sandwiched and fixed by the ground bracket 27. The coaxial cable 40 and the antenna element 20a are connected.

  The vehicle antenna 20 attached to the ceiling plate 14 with the conductive sheet 30 interposed therebetween is attached to the vehicle 10 as shown in FIG. 1 together with the ceiling plate 14, and one end of the ceiling plate 14 is a frame of the vehicle 10. When fixed to 13, it is arranged in a space between the ceiling plate 14 and the roof 11.

  The vehicle antenna 20 of the present embodiment is disposed so that the ground plate 22 of the antenna element 20a is electrically connected to the conductive sheet 30 that is larger than the ground plate 22, and thus the conductive sheet 30. Has the effect of electrically expanding the ground plate 22 of the antenna element 20a. For this reason, the conductive sheet 30 functions as a ground plane of the antenna element 20a together with the ground plate 22, and the radiation characteristics of the antenna are improved. The above effect can be obtained even when the conductive sheet 30 is not electrically connected to the frame 13 of the vehicle 10. For this reason, in the vehicle antenna 20 of this embodiment, there exists an effect that sufficient radiation characteristics can be obtained even if the antenna element 20a and the frame 13 of the vehicle 10 are not connected by a ground wire. In addition, the conductive sheet 30 may be formed on the frame 13 of the vehicle 10, and in this case, the radiation characteristics of the antenna become better.

  Furthermore, since the vehicle antenna 20 of the present embodiment has the conductive sheet 30 disposed between the radiation plate 21 and the passenger compartment, the vehicle antenna 20 is suppressed from being affected by noise in the passenger compartment. There is an effect that the deterioration of the antenna performance due to noise in the passenger compartment can be suppressed.

  Another embodiment of the present invention will be described with reference to FIG. Parts similar to those of the embodiment described with reference to FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof is omitted. In the embodiment shown in FIG. 4, the shape of the reinforcing member 29 that connects the radiation plate 21 and the ground plate 22 is a groove shape, and the radiation plate 21 faces the ground plate 22 at an intermediate position between the radiation plate 21 and the ground plate 22. A plate-like arm 29a is provided, and a projection 29b is provided on the ground plate 22 side of the arm 29a. The ceiling plate 14 is provided with a plate-like bracket 16 by integral molding in place of the clip 15 shown in FIGS. 2 (c) and 2 (e). On the distal end side of the bracket 16, a square engagement hole 17 into which the projection 29b at the distal end of the arm 29a is fitted is provided.

  As shown in FIG. 4, the conductive sheet 30 is overlaid on the ceiling plate 14, and the bracket 16 integrally molded with the ceiling plate 14 is aligned with the groove of the reinforcing member 29 of the antenna element molded product 20 b. When the projection 29b at the distal end of the arm 29a is fitted into the engagement hole 17 of the bracket 16, the projection 29b engages with the engagement hole 17, and the antenna element molded product 20b has a conductive sheet between the ground plate 22 and the ceiling plate 14. 30 is sandwiched and fixed to the ceiling plate 14.

  This embodiment has the same effects as the previously described embodiments.

  10 vehicle, 11 roof, 12 rear window glass, 13 frame, 14 ceiling plate, 15 clip, 16 bracket, 17 engagement hole, 20 vehicle antenna, 20a antenna element, 20b antenna element molded product, 21 radiation plate, 22 contact Ground plate, 23 Connection plate, 24 Feed plate, 25 Square hole, 26 Round hole, 27 Ground bracket, 28 Feed end, 29 Reinforcement member, 29a Arm, 29b Protrusion, 30 Conductive sheet, 40 Coaxial cable, 41 Shield wire, 42 Core wire.

Claims (2)

An insulating base portion;
An antenna element including a conductive ground plate attached to the base portion, a conductive radiation plate disposed opposite to the ground plate, and a conductive connection plate electrically connecting the radiation plate and the ground plate When,
A conductive thin plate that is larger than the ground plate and sandwiched between the base portion and the ground plate so as to protrude beyond the periphery of the ground plate;
An antenna for a vehicle. The vehicle antenna according to claim 1,
The base body is a resin vehicle interior plate,
The antenna element is disposed between the resin vehicle exterior plate and the vehicle interior plate,
An antenna for a vehicle.

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