JPS6133694Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an antenna device for a vehicle, and is particularly applicable to an antenna device in which the antenna element is configured using a single rod or a telescopic pole with a small number of stages, and is stored in a dead space of a vehicle when it is reduced. The present invention relates to a vehicle antenna device suitable for.

Vehicle antenna devices of various shapes and structures have been known in the past, but at present each antenna device has its own advantages and disadvantages and is put on the market.

One of these is a system that utilizes the dead space of a vehicle and stores the antenna in this dead space when the antenna is reduced. Conventionally, this type of antenna device uses a single small diameter rod or a small diameter long rod. A two-stage antenna element with a thick diameter and short rod is used, and compared to other types of antenna elements, the number of stages is fewer and the element length per stage is longer, which requires less storage space when stored. However, as mentioned above, it can be stored not only in dead spaces such as the engine room or the underside of the dash board, but also in the pillars, which has the advantage that extremely long antenna elements can be used.

In such an antenna element, the protruding part is located on the top surface of the roof or the top end surface of the pillar, but by utilizing the semi-rigidity of the element, it can be curved and stored in a dead space when reduced. When extended, it can be in a straight-stretched state.

The reason why antenna devices with such a structure have come into widespread use in recent years is as follows.

(1) The antenna extraction opening, that is, the antenna base attachment part to the vehicle body, is the roof surface on the driver's seat side, and the upper end of the pillar surface, and the long section from here to the inside of the pillar and reaching the engine room is where the antenna is stored. It can be used as space, the length of the antenna when stored can be increased, and the number of antenna stages can be reduced, reducing costs compared to other types of antennas. Since there are fewer sliding parts, it is strong and lasts a long time. Moreover, since the drawer opening can be set at the above-mentioned location, in the case of a manual type, the driver can conveniently perform expansion and contraction operations while remaining in the driver's seat.

(2) Although this type of antenna is installed on the pillar, it is a shield pillar type and is installed inside the pillar, so it can prevent wind noise that is annoying to the driver when driving at high speed, and the antenna element when extended. Since the antenna further protrudes from the roof (the highest part of the vehicle), it can effectively capture radio waves when receiving radio waves, resulting in a highly sensitive antenna with excellent electrical characteristics.

Because of these advantages, this type of antenna device is often used, but there are problems in actual use as described below.

(1) Some car models have streamlined bodies, but in these cases the pillars themselves have a large slope. Therefore, the antenna is attached to the roof in a lying position, and the distance between the roof and the antenna element becomes narrower.

(2) This type of antenna element is generally made of stainless steel from the viewpoint of corrosion resistance, and is made of a semi-rigid material that can be easily bent so that it can be stored along a curved dead space. For example, the smallest diameter element, which is the smallest diameter element, uses a solid material with a diameter of 2.5 to 3 mm, and in the case of an antenna consisting of a single pole, the element length is about 1 m, and 2.5 to 3 mm in diameter is used. Even in the case where stage-type large diameter short elements are arranged, the small diameter pole length is 60 cm or more. For this reason, when the vehicle is running, air resistance such as wind pressure and running vibrations are transmitted to the small-diameter element of the antenna element, and the element repeatedly bends while the vehicle is running, causing the tip of the element to hit the roof surface and cause damage, or cause the antenna to shake. Therefore, there is a risk that problems such as unstable reception may occur.

The present invention was devised in view of the current situation, and its purpose is to provide a vehicle antenna device that is easy to store in and pull out from a vehicle, and that provides good reception without causing the antenna element to shake when extended. is to provide.

After observing various types of antennas, the present applicant discovered that there was a mistake in the conventional design of this type of antenna.

That is, this type of antenna element uses a semi-rigid conductive metal solid material that is easily bent because it needs to be bent or bent when stored.
In order to obtain appropriate flexibility, the material,
Not only the thickness of the material, but also the length from the fulcrum (the length of the material) is relevant, and in order to ensure sufficient strength in terms of running wind pressure, etc., in the case of a single element, 1 m
The length and diameter of 3mm have been selected and used conceptually. However, although this antenna element needs to be flexible when stored, flexibility causes the above-mentioned problems when extended, so it is rather preferable that the antenna element does not have arrogant properties.

In order to satisfy these conflicting requirements, the present applicant observed the repeated bending state of the antenna element during expansion and found the following.

(1) Deflection when the antenna element is extended is initially caused by wind pressure and vibration, but when the weight of the material itself is added to this, the antenna element becomes large in amplitude and repeatedly deflects. Therefore, if the antenna element is constructed using a thin pipe material with the same outer diameter as the conventional one in order to reduce its own weight, it will bend slightly due to wind pressure, but the amount of deflection will be smaller than before because the dead weight load is eliminated. Instead, repeated bending has become almost impossible. In other words, the conventional idea that if a long antenna element with a small diameter is to withstand the wind pressure during driving, it should be made solid is wrong, and it is preferable to make it from pipe material. In terms of strength, it is sufficient because it eliminates the load of its own weight.

(2) When storing the antenna element, the antenna element is inserted into a flexible guide tube provided along the curve in the dead space, but if the element is made of pipe material, the antenna element is inserted along the curved part. The guide tube is easier to insert than the conventional solid material, but on the other hand, if the stored state is maintained for a long time, the guide tube tends to take on a curved shape.
However, to pull out the antenna element, pinch the tip and pull it to correct the bending and most of the parts return to their straight shape without any problems. However, after the upper part of the stopper provided at the lower end of the element is inserted into the power supply spring part and the extended state holding spring part in a curved state, the above-mentioned tensile force is applied, so a large force to spread the spring part is applied during that time. In addition, as the sliding motion is repeated, the elasticity of the power supply or holding spring weakens, causing problems such as loss of the ability to maintain the extended state, and play in the power supply section, which causes noise to be mixed in during reception.

Based on this knowledge, the present invention consists of forming the antenna element from a hollow material, providing a slit-like hole at the lower end of the antenna element, and injecting synthetic resin into the lower end of the antenna element through this hole to extend the antenna. In some cases, at least up to the position corresponding to the power feeding spring and the extension holding spring are made solid, and a stopper is formed on the outside of the antenna element, which is made of synthetic resin at the hole position and is integral with the synthetic resin injected into the antenna element. This is to solve the problems that arise when the element is made hollow.

Hereinafter, embodiments of the present invention will be described based on the drawings.

As shown in FIG. 1, the antenna device according to this embodiment includes a flexible tube 2 that passes through a pillar 1a of a vehicle 1 and is disposed in an engine compartment 1b, and an upper end of this flexible tube 2 that is connected to a pillar 1a. It is comprised of a mounting bracket 3 fixed to the upper end surface, and an antenna element 4 housed within the flexible tube 2 and pulled out upward from the position of the mounting bracket 3 to the outside of the vehicle 1.

As shown in FIG. 2, the mounting bracket 3 is a cylindrical base 5 that extends from the inside of the vehicle 1 to the outside of the vehicle 1, and is fitted onto a protruding portion of the base 5 to the outside of the vehicle 1 via a roof washer 6. combined insulation cap 7;
It consists of a cap nut 8 that is screwed onto the upper end of the base 5 to fix the insulating cap 7, and a cylindrical neck holder assembly 9 and a power supply unit assembly 10 are press-fitted into the base 5 sequentially from the lower end to supply power. A power supply tube 11 is disposed within the section assembly 10, and an element spring 12, which functions as both a power supply spring and an extension holding spring, is inserted and fixed within the power supply tube 11. The antenna element 4 is inserted through these axial center positions.
A fixed coaxial feeder 14 is drawn out from the power supply tube 11 via a ground lug 13.

As shown in FIGS. 2 and 3, an element stop portion 11a is formed at the lower end of the power supply tube 11 protruding from the lower part of the power supply assembly 10, and is curved toward the axis and has a small diameter. The flexible tube 2 fitted to the outer periphery of the lower end of the power supply tube 11 is connected to the power supply tube 11 by a retaining ring 15 disposed at the element stop portion 11a. This flexible tube 2 has a second
As shown in the figure, a spacer 16 made of polyurethane, etc.
is attached to prevent the flexible tube 2 from moving within the dead space of the vehicle 1.

The antenna element 4 is made of stainless steel or the like.
It is formed of a single, narrow-diameter cylindrical material, and has a top 17 at its distal end protruding from the mounting bracket 3, and a stopper 18 at its lower end located within the flexible tube 2.

A hole such as a slit 19 is bored in the lower end of the antenna element 4 as shown in FIG. It is formed. Furthermore, a synthetic resin 2 integral with the stopper 18 is provided within a certain area inside the lower end of the antenna element 4.
0 is injected and fixed in one step with the molding of the stopper 18, making the lower end of the antenna element 4 solid. It is preferable that the synthetic resin 20 is injected to a portion beyond the upper end of the mounting bracket 3 when the antenna element 4 is fully extended, but it is necessary to inject at least a portion beyond the element spring 12.

The stopper 18 closes the element stop portion 1 of the feed tube 11 when the antenna element 4 is fully extended.
1a to prevent the antenna element 4 from coming off.

Next, the effect will be explained.

When extending the antenna element 4, first grasp the top 17 and pull it out. Then, the antenna element 4, which had been curved following the curved state of the flexible tube 2, is corrected into a straight shape by the mounting bracket 3 and can be pulled out. Then, the stopper 18 connects the power supply tube 11
The antenna element 4 is prevented from being pulled out at the position where it comes into contact with the element stop portion 11a, and this state is the fully extended state of the antenna element 4. At this time, since the synthetic resin 20 is injected into the lower end portion of the antenna element 4, this portion is always in a straight-stretched state, so that no excessive load is applied to the element spring 12.

When reducing the size of the antenna element 4, the protruding portion of the antenna element 4 from the mounting bracket 3 is grasped and pushed into the mounting bracket 3 side. Then, the antenna element 4 is curved following the curved state of the flexible tube 2 and is housed within the flexible tube 2. And top 1
Reduction is prevented at the position where 7 comes into contact with the mounting bracket 3, and this state becomes a fully retracted state. At this time, since the stopper 18 and the lower end spherical head 20a protruding from the lower end of the antenna element 4 are made of synthetic resin, smooth sliding movement within the flexible tube 2 is achieved.

In the above embodiment, the antenna element 4 is of a single pole type, but a multi-stage type may be used, or the element spring 12 may be divided into a power feeding spring and a spring for maintaining the extended state. Furthermore, the function of only one of the two springs may be achieved by a separate structure.

As explained above, according to the present invention, it is possible to straighten the lower end of the antenna element by injecting synthetic resin, so that excessive load is not applied to the spring for power feeding and for holding the spring, and the stopper is not damaged. There's nothing to do. Furthermore, since the lower end portion of the antenna element that comes into contact with the flexible tube is coated with synthetic resin, the pressure-contact sliding inside the flexible tube is smooth, and the antenna element can be moved in and out smoothly. Since the synthetic resin injected into the lower end of the antenna element and the stopper are integrated, the stopper can be stably fixed. Furthermore, the antenna element part exposed to the outside when extended is completely hollow, making it possible to reduce weight.Therefore, there is no shaking due to wind pressure, etc., and there is no risk of hitting the roof etc. with the tip of the antenna element. Also, since there is little vibration, reception is good. In this way, according to the present invention, the lower end of the antenna element can be made solid by simply injecting synthetic resin into the antenna element, so that special parts are not required and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing how the antenna device is attached to a vehicle, FIG. 2 is a sectional view showing an embodiment of the present invention, and FIG. 3 is an enlarged sectional view of the main part of FIG. 2. DESCRIPTION OF SYMBOLS 1... Vehicle, 2... Flexible tube, 3... Mounting bracket, 4... Antenna element, 12... Element spring, 18... Stopper, 19... Slit (hole), 20... Synthetic resin.

Claims (1)

[Claims for Utility Model Registration] 1. A vehicle in which a stopper is provided at the lower end of the antenna element to prevent the antenna element from coming off from the mounting bracket, and a power feeding spring and an extension holding spring are slidably connected to the antenna element. In the antenna device, the antenna element is formed of a hollow material, and a hole is provided at the lower end of the antenna element,
A synthetic resin is injected into the lower end of the antenna element through this hole to make it solid at least up to the position corresponding to the spring when the antenna is extended. A vehicle antenna device in which a stopper is formed on the outside of the antenna element. 2. The vehicle antenna device according to claim 1, wherein the hole at the lower end of the antenna element is a slit penetrating the peripheral wall surface of the element.