JPH028404Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a multi-stage multi-frequency antenna suitable as a vehicle-mounted multi-frequency receiving antenna.

[Conventional technology]

Traditionally, rod antennas with a loading coil section, such as multi-frequency receiving antennas, are heavy and large-diameter ones, where the loading coil section consists of a coil wound around an insulated bobbin and a capacitor attached externally to both ends of the coil. Therefore, this loading coil portion becomes a hindrance, and even if it is configured to be telescopic, the storage length cannot be made sufficiently short. Therefore, when such a multi-frequency receiving antenna is installed in a car, the part exposed to the outside of the car is large, and the weight of that part is also increased, which tends to result in insufficient strength. To compensate for this, the entire antenna must be large. There was a tendency to become

[Purpose of invention]

Therefore, the present invention has been developed to reduce the diameter and weight of the loading coil so that it does not interfere with expansion and contraction, and to create a compact and lightweight device that provides sufficient strength when expanded, yet can be stored compactly when contracted. The purpose of the present invention is to provide a multi-stage multi-frequency antenna.

[Structure of the idea]

For this purpose, the present invention provides a conductive film layer having a coil pattern on the surface of a pole made of insulating resin and covering it with a resin coating. An antenna element comprising a capacitor sleeve having a sliding spring for electrical connection is fitted and fixed so as to be electrically conductive with the conductive film layer and facing the coil pattern via a resin film. The gist is:

【Example】

An embodiment of the present invention will be described below based on the drawings. Figure 1 shows one antenna element according to the present invention.
An example is shown in which the top bar is provided as a step-extendable top bar, and in the figure, numeral 1 is the top bar and 2 is the proximal pole. As shown in FIG. 2, the top bar 1 is mainly made of a rod material 11 made of insulating resin such as FRP, and a conductive film layer 12 is formed on the surface thereof by appropriate means such as printing, plating, or vapor deposition, and the surface is further coated with a conductive film layer 12. It is constructed by covering it with a film 13 of an insulating paint made of resin having a dielectric constant. The conductive film layer 12 of the top bar 1 has a coil pattern 14 located on the base end side of the top bar 1.
is formed in advance by masking the bar 11 when forming the conductive film layer 12.
(See Figures 2 and 3). A capacitor sleeve 3 made of a conductive metal is fitted to the base end of the top bar 1, and a hole 31 formed from the circumferential surface of the sleeve 3 to the conductive film layer 12 of the top bar 1 is filled with solder. The sleeve 3 and the conductive film layer 12 are electrically connected, and the sleeve 3 and the top bar 1 are coupled. This capacitor sleeve 3 has a predetermined capacitance because the fitting portion 32 for the top bar 1 is closely opposed to the coil pattern 14 with the aforementioned coating 13 interposed therebetween. In addition, a step 3 is provided in the fitting portion 32.
The tip of the drive cord 4 is inserted into a large-diameter connecting portion 34 that extends in the axial direction from the base end of the top bar 1 through the connecting portion 3, and is crimped from the outer periphery of the connecting portion 34 to connect the drive cord 4 to the capacitor sleeve. It is connected to 3. A sliding spring 35 made of a conductive metal is fixed to the outer periphery of the connecting portion 34 of the capacitor sleeve 3 by soldering. The proximal pole 2 connects the top bar 1 with the above-mentioned sliding spring 3.
A ring member 23 is clamped and fixed between a caulked part 21 formed at the tip of the conductive metal pipe and a small-diameter constricted part 22 at the tip. By locking the top bar 1, the top bar 1 is prevented from coming off. The ring member 23 is made of synthetic resin or the like so as not to damage the coating 13 when the top bar 1 expands and contracts. In the above configuration, when the drive cord 4 is pushed out by the operation of the drive unit (not shown), the top bar 1 extends from the base end pole 2, is prevented from coming out by the ring member 23, and is fully extended and contracted. In this state, the conductive film layer 12 of the top bar 1 forms an antenna circuit with a path of the capacitor sleeve 3, the sliding spring 35, and the base end pole 2 via the coil pattern 14. At this time, the coupling part 32 of the capacitor sleeve 3 closely faces the coil pattern 14 through the coating 13 and functions as a capacitor with a predetermined capacitance, so an LC circuit is constructed in the middle of the antenna circuit, and a multi-frequency It is possible to perform the intended function as a receiving antenna. The loading coil portion constituting such an LC circuit is configured as a coil with the coil pattern 14 formed by the conductive film layer 12, and as a capacitor with the connecting portion of the capacitor sleeve 3 that faces closely to the coil pattern, and the entire loading coil portion is configured as a capacitor. as top bar 1
Since it is lightweight and has a small diameter, which is slightly thicker than the top bar, it does not interfere with contraction into the base end pole 2, and by pulling back the drive cord 4, the top bar 1 can be completely stored between the base end poles 2. Further, since the coil pattern 14 as the coil of the LC circuit is covered with the coating 13 and further covered with the fitting part 32 of the capacitor sleeve 3, and these can be stored in the proximal pole 2, the coil will not be damaged. There are almost no FIG. 4 shows another embodiment of the invention, in which the antenna element is provided as an intermediate pole. In this case, a small-diameter intermediate pole is fitted to the intermediate pole, and there is no need to fix the drive cord, so in this point it is slightly different from the previous embodiment, but other parts are the same as in the previous embodiment. Since the parts are substantially the same as those shown in FIG. In FIG. 4, reference numeral 5 indicates an intermediate pole, which is mainly composed of a pipe material 51 made of insulating resin such as FRP, and a conductive film layer 12, a coil pattern 14, a coating 13, etc. are provided on the surface thereof. The capacitor sleeve 6 that is fitted and fixed to the intermediate pole 5 has a straight tube shape without steps, and its proximal end surface 6
1 is aligned with the base end surface 52 of the intermediate pole 5. Further, a large diameter portion 71 of a stepped cylindrical retaining fitting 7 is fitted into the tip of the intermediate pole 5. That is, as shown in FIG. 5, at the tip of the intermediate pole 5, the coating 13 is removed in a ring shape to expose the conductive film layer 12, and the large diameter portion 71 of the retainer 7 is attached to the outer circumference. It is fitted with its diameter substantially matching the outer circumferential diameter of the coating 13 and fixed by soldering or the like. The small-diameter portion 72 of the retaining fitting 7 has an inner circumferential diameter that substantially matches the inner circumferential diameter of the pipe material 51 and protrudes from the tip of the intermediate pole 5, and a small-diameter constricted portion 73 is formed at the protruding end. ing. Therefore, by sequentially fitting other similarly constructed intermediate poles into this intermediate pole 5 and locking the sliding spring 35 of the small diameter stage with the small diameter constricted part 73 of the retaining metal fitting 7, a multi-stage expansion/contraction system is achieved. Configure. Note that the most extreme pole may have the structure shown in FIG. 1 and the drive cord 4 may be attached thereto. This embodiment not only has the functions and effects of the above-mentioned embodiments, but also allows for more compact storage since it can be expanded and contracted in multiple stages. Another advantage is that each antenna element can be configured with an LC circuit. In addition, coil pattern 1 in the above embodiment
4 and the capacitor sleeve that closely opposes the capacitor sleeve are not limited to the base end of the top bar 1 or the intermediate pole 5, and can be arranged at any position. In this case, the sliding spring 35 Instead of being attached to the sleeve 3, it may be attached to a separate member or directly to the base end of the top bar 1 or intermediate pole 5.

[Effect of the idea]

As explained above, according to the present invention, the loading coil section consisting of a coil and a capacitor consists of a coil pattern of a conductive film layer formed on the pole surface of an antenna element, and a sleeve that faces this through a resin coating. Because of this structure, the loading coil portion can be made lightweight and small in diameter. Therefore, it is possible to provide a small and lightweight multi-stage multi-frequency antenna that has sufficient strength when extended and can be stored compactly when contracted by configuring each stage antenna element in a multi-stage expandable type. In addition, since the loading coil section is configured to cover the coil pattern with a sleeve, the coil is less likely to be damaged. Since the loading coil portion has a small diameter and does not interfere with expansion and contraction, there is a degree of freedom in placement, and a multi-stage trap can be constructed at any location.

[Brief explanation of drawings]

Fig. 1 is a partially sectional side view showing one embodiment of the present invention, Fig. 2 is a half sectional view of the same main part, Fig. 3 is an external view of the coil pattern, and Fig. 4 is a side view of an embodiment of the present invention. FIG. 5 is a partially sectional side view showing an embodiment of the present invention, and FIG. 5 is a half sectional view of the retaining fitting. DESCRIPTION OF SYMBOLS 1... Top bar, 11... Bar material, 12... Conductive film layer, 13... Coating, 14... Coil pattern, 2... Base end pole, 21... Caulking part, 22
...Small diameter throttle part, 23...Ring member, 3...Capacitor sleeve, 31...Hole, 32...Fitting part, 33...Step, 34...Connection part, 35...Sliding spring, 4... ... Drive cord, 5 ... Intermediate pole, 51 ... Pipe material, 52 ... Base end surface, 6 ...
Capacitor sleeve, 61... proximal end surface, 7... retaining fitting, 71... large diameter section, 72... small diameter section, 7
3...Small diameter aperture part.

Claims (1)

[Scope of utility model registration request] A conductive film layer with a coil pattern is covered with a resin film on the surface of a pole made of insulating resin, and this pole is equipped with a sliding spring that is slidable against the next stage pole, prevents it from coming off, and makes an electrical connection. A multi-stage multi-frequency antenna element comprising: a capacitor sleeve having a capacitor sleeve electrically connected to the conductive film layer and fitted and fixed so as to face the coil pattern via a resin film. antenna.