JPH08148932A - Antenna device and manufacture therefor - Google Patents

Abstract

PURPOSE: To mass-produce antenna devices provided with a sufficiently highly reliable waterproof property by a simple waterproof structure by adopting a structure capable of easily performing the airtight property test of individual products. CONSTITUTION: For this antenna device, an antenna element 1 is housed in the flat waterproof type case 2 made of plastic and an antenna cable 3 is pulled out from a case side part. A small hole 2d for connecting the inside and outside of the case is formed at the center part of a case bottom surface recessed part 2c, a magnet attracting device 5 for which a yoke 5a and a magnet 5b are combined is adhered and fixed to the bottom surface recessed part 2c by a double coated adhesive sheet 7 provided with the airtight property and the small hole 2d is airtightly covered with the double coated adhesive sheet 7. A thick protective sheet 8 provided with elasticity is stuck to the attraction surface of the magnet attracting device 5 and a peripheral part by an adhesive agent and the bottom surface recessed part 2c is airtightly covered with the protective sheet 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device for a navigation device using GPS (Global Positioning System), and in particular, it is magnetically attached to a metal part of an automobile or a ship by a magnet for use outdoors. The present invention relates to an improved type of antenna device and a method of manufacturing the same.

[0002]

2. Description of the Related Art As is well known, an antenna device for a vehicle, which receives GPS radio waves, has a flat waterproof case made of plastic with an antenna element built-in, and an antenna cable from the side. Has been pulled out. This antenna device is attached to the outer surface of a steel plate automobile body (such as a trunk lid) by utilizing the magnetic attraction force of a magnet. In the case of an antenna device that is used by being attached to the outer surface of an automobile or a ship, it is naturally required to have sufficient waterproofness because of the environment in which it is used. Therefore, the conventional case structure has a double structure in which an antenna element is housed in an inner case having a sufficient waterproof property using a gasket or the like, and the entire case is covered with an outer case.

[0003]

In the waterproof structure in which the case is doubled, the case structure is complicated, the assembly process is complicated, the cost is high, and the outer diameter of the device tends to be large. . In addition, the waterproof structure of the double case,
Since it is extremely troublesome to test the waterproofness (airtightness) of the inner case after assembling, generally, the airtightness test is not performed for all individual products. Further, in the conventional waterproof structure of the double case, since the outer case is not highly waterproof, water enters the outer case under severe conditions such that the entire antenna device is submerged in water, and the water is kept for a long time. There is a problem that it stays inside and causes corrosion of metal parts such as the magnet adsorber and screws.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to adopt a structure capable of easily carrying out an airtightness test of individual products, thereby having a simple waterproof structure and sufficient reliability. The purpose is to enable mass production of highly waterproof antenna devices.

[0005]

According to the present invention, there is provided an antenna device in which an antenna element is housed in a flat, waterproof case made of plastic, and an antenna cable is pulled out from a side portion of the case. A small hole that connects the inside and outside of the case is formed in the center of the case, and a magnet attractor that combines a dish-shaped yoke and a flat ring magnet is applied on both sides of an airtight sheet material with double-sided adhesive The sheet is adhesively fixed to the bottom concave portion of the case, and the double-sided adhesive sheet hermetically closes the small hole, so that the attraction surface of the magnet attractor and the peripheral portion of the case bottom concave portion are thick and elastic. A protective sheet is attached with an adhesive, and the concave portion on the bottom surface of the case protects the magnet attractor with this protective sheet. It has a structure which is closed in an air-tight in a state in which the warehouse was.

In manufacturing the antenna device, the antenna element is housed in the case, and is formed on the bottom surface of the case before the double-sided adhesive sheet and the magnet attractor are bonded to the bottom recess. A pad for vacuum suction is applied to the small hole, and the air in the case is sucked by a vacuum suction test device that communicates with the pad to perform an airtightness test of the case,
When the test result was good, the double-sided pressure-sensitive adhesive sheet, the magnet attractor, and the protective sheet were attached.

[0007]

In the step before the antenna element is housed in the case and the double-sided pressure-sensitive adhesive sheet and the magnet attractor are bonded to the bottom surface concave portion, only the small holes formed on the bottom surface of the case are attached to the inside and outside of the case. It is a communication path. By testing the airtightness of the case with a vacuum suction device through the small holes, it is possible to easily find a defect in the waterproof structure portion of the case. For those with good test results, the small holes are closed with the double-sided adhesive sheet for attaching the magnet adsorber, and the bottom recess of the case is closed with the protective sheet to prevent damage to the attachment target such as the car body. . In this way, since the small holes are doubly closed by the double-sided pressure-sensitive adhesive sheet and the protective sheet, which are members for other purposes, the waterproofness of the case can be enhanced without taking special airtight means.

[0008]

1 and 2 show the construction of an on-vehicle antenna device according to an embodiment of the present invention. As shown in detail in FIG. 1, the antenna element 1 is sealed in a flat case 2 made of plastic, and an antenna cable 3 is drawn out from the side portion of the case. The case 2 is composed of an upper case 2a and a lower case 2b, and a gasket 4 is sandwiched between the combination surfaces of the upper case 2a and the lower case 2b so as to have waterproofness and airtightness, and both are fastened with a plurality of screws 10. Also, the heat-shrinkable tube 3a is attached and covered at the base of the antenna cable 3, and the heat-shrinkable tube 3a is sandwiched between the upper and lower cases 2a and 2b and squeezed to ensure that the cable 3 has a waterproof property. It is airtight.

A circular recess 2c is formed on the bottom surface of the lower case 2b, and a small hole 2d for communicating the inside and outside of the case is formed at the center of the bottom surface recess 2c. The magnet attractor 5 is attached in a state of being fitted into the bottom surface recess 2c of the lower case 2b. As shown in detail in FIG. 2, the magnet attractor 5 is a combination of a dish-shaped yoke 5a having a central convex portion and a flat ring-shaped magnet 5b.
The ring-shaped magnet 5b is joined to the yoke 5a by a double-sided adhesive sheet 6, and the yoke 5a is joined to the recess 2c on the bottom surface of the case by a double-sided adhesive sheet 7. The double-sided pressure-sensitive adhesive sheet 7 is obtained by applying a strong acrylic-based pressure-sensitive adhesive on both sides of a sheet of a fully closed-cell acrylic foam material. When the magnet adsorber 5 is attached to the recess 2c on the bottom surface of the case via the double-sided adhesive sheet 7, the small hole 2d formed in the center of the bottom surface is hermetically and strongly closed.

The lower surface of the magnet attractor 5 and the lower case 2b
The lower surface (around the bottom surface recessed portion 2c) is substantially flush, and this is the vehicle body joining surface. A thick and elastic epoxy-impregnated polyester cloth sheet (for example, NO.351 manufactured by Nitto Denko Corporation) or a protective sheet 8 made of a silicone rubber sheet is attached to this vehicle body joint surface with a strong adhesive. The protective sheet 8 is also a sheet material having airtightness, and the sheet bottom surface recess 2
c is airtightly closed with the magnet adsorber 5 built-in. That is, the small hole 2d is doubly airtightly sealed by the double-sided adhesive sheet 7 and the protective sheet 8.

In the manufacturing process of the antenna device having the above structure, the antenna element 1 is housed in the case 2 and before the double-sided adhesive sheet 7 and the magnet attractor 5 are bonded to the bottom recess 2c, as shown in FIG. As shown, a pad 11 for vacuum suction is applied to the small hole 2d formed on the bottom surface of the case 2, and the air inside the case 2 is sucked by a vacuum suction test device 12 communicating with the pad 11. Perform air tightness test. When the result of this test is good, the double-sided adhesive sheet 7, the magnet adsorber 5, and the protective sheet 8 are attached as described above.

[0012]

According to the present invention, the antenna element is housed in the case, and only the small hole formed on the bottom surface of the case is formed before the double-sided pressure-sensitive adhesive sheet and the magnet attractor are bonded to the recess on the bottom surface of the case. It is a path that connects the inside and outside. By testing the airtightness of the case with a vacuum suction device through the small holes, it is possible to easily find a defect in the waterproof structure portion of the case. For those with good test results, the small holes are closed with a double-sided adhesive sheet for attaching the magnet adsorber, and the bottom surface recess of the case is closed with a protective sheet that does not damage the object to be attached such as an automobile body. In this way, since the small holes are doubly closed by the double-sided pressure-sensitive adhesive sheet and the protective sheet, which are members for other purposes, the waterproofness of the case can be enhanced without taking special airtight means. As described above, since the airtightness test of each product can be easily performed, it is possible to mass-produce the antenna device having a simple waterproof structure and sufficiently reliable waterproofness.

Since the bottom surface of the case is covered with a thick and elastic protective sheet, the contact with the body surface of an automobile or the like is significantly softer than that of a conventional type antenna device in which a magnet is housed in a plastic case. , There is almost no danger of damaging the painted surface of the body. Further, the protective sheet is remarkably thinner than the thickness of the bottom plate of the plastic case in the case of the conventional magnet built-in type, and therefore the gap between the magnet attractor and the vehicle body surface etc. is kept sufficiently small. Therefore, a strong magnetic attraction force can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a vehicle-mounted antenna device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a magnet attractor in the apparatus of the above embodiment.

FIG. 3 is a view showing a state in which an airtight test is being performed on the antenna device assembly line.

[Explanation of symbols]

1 antenna element 2 case 2a upper case 2b lower case 2c recess 2d small hole 3 antenna cable 3a heat-shrinkable tube 4 gasket 5 magnet adsorber 5a dish-shaped yoke 5b ring-type magnet 6, 7 double-sided adhesive sheet 8 epoxy-impregnated polyester cloth sheet or Protective sheet made of silicone rubber sheet 9 Car body 11 Vacuum suction pad 12 Vacuum suction tester

Claims (2)

[Claims] 1. An antenna device in which an antenna element 1 is housed in a flat, waterproof case 2 made of plastic, and an antenna cable 3 is pulled out from a side portion of the case, wherein a central portion of a bottom recess 2c of the case 2 is provided. Has a small hole 2d that communicates the inside and outside of the case, and a magnet adsorber 5 that combines a dish-shaped yoke 5a and a flat ring magnet 5b is coated on both sides of an airtight sheet material with adhesive. The double-sided pressure-sensitive adhesive sheet 7 is adhered and fixed to the bottom surface recess 2c of the case 2 by the pressure-sensitive adhesive sheet 7.
The small hole 2d is hermetically closed by the above, and a thick and elastic protective sheet 8 is adhered to the adsorbing surface of the magnet adsorber 5 and the peripheral portion of the case bottom recess 2c with an adhesive, and An antenna device, characterized in that a bottom surface recess (2c) of the case (2) is airtightly closed by a protective sheet (8) with the magnet adsorber (5) incorporated therein. 2. A step before manufacturing the antenna device according to claim 1, wherein the antenna element 1 is housed in the case 2 and the double-sided adhesive sheet 7 and the magnet attractor 5 are bonded to the bottom surface recess 2c. Then, the vacuum suction pad 11 is applied to the small hole 2d formed on the bottom surface of the case 2, and the air in the case 2 is sucked by the vacuum suction test device 12 communicating with the pad 11. The airtightness test is performed, and the double-sided adhesive sheet 7, the magnet adsorber 5, and the protection sheet 8 are attached to those having good test results, and a method for manufacturing an antenna device.