JPS59127404A - Antenna device for automobile - Google Patents

Abstract

PURPOSE:To perform expanding operation control smoothly by rotating an endless wire extended between a couple of pulleys and driving an antenna rod linearly. CONSTITUTION:The linear antenna rod 11 is set axially movably in a guide cylinder 30. A worm gear 42 provided to a motor housing 33 transmits the rotation of a motor 44 through a worm 43. A driving pulley 45 is provided coaxially and integrally with the worm gear 42. This pulley 45 set closely to the antenna rod 11, a driven pulley 46 is provided to the pulley 45 toward the base terminal of the antenna rod 11, and the endless wire 47 is extended between the pulleys 45 and 46. When the driving pulley 45 is rotated at the endless connection part of the wire 47, rotating force is transmitted to the antenna rod 11 through springs 48 and 49 to move up or down the rod 11 linearly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to an antenna device for an automobile in which the drive mechanism is simplified and the expansion and contraction operations are executed smoothly.

An automobile antenna is provided, for example, in correspondence with a gunnet portion of a vehicle body, and is configured to be extendable and retractable so that it can be pulled out when receiving a radio signal and stowed at other times. In this case, in order to improve reception sensitivity, the antenna is constructed to be long to some extent, and the antenna rod is divided into multiple stages, and each divided rod slides into contact with each other and is stored in the hollow part one after another. It is configured to be expandable and contractible.

In order to automatically extend and retract an antenna using such a split rod, for example, a cable is connected to the split rod at the tip through the hollow part of the rod, and the cable is wound around a drum, or unwound and pushed out. ,
The antenna is retracted and stored, and the wall is extended so that it can be set for reception.

However, in the antenna device having such a configuration, since the antenna rod is divided, the number of parts inevitably increases, and the cable installation structure for the expansion and contraction operation becomes complicated. In addition, resin cables are usually used as cables for this expansion and contraction operation, and when the antenna rises, a pushing force acts on it, causing large losses due to breakage due to scratches and increased frictional resistance. An unbalance occurs between the force of the drive mechanism and the force of the lowering stopper, making it difficult to smoothly control the operation of the drive mechanism.

This invention was made in view of the above points, and it is possible to make the antenna rod sufficiently short so that it can be configured as a single straight line, and also without using a cable mechanism that is driven by winding. It is an object of the present invention to provide an antenna device for an automobile that is sufficiently simple in structure and can smoothly extend and contract and control life.

That is, in the antenna device according to the present invention, a linear antenna rod is set to be movable in an axial direction, and an endless wire is provided parallel to the antenna rod and stretched between a pair of googly. The wire is connected to the antenna rod via a telescopic spring, and one of the pair of googly is rotationally driven by a motor via a deceleration mechanism, for example.

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows the configuration of a radio receiving device for a car that is combined with an antenna device. Reference numeral 11 denotes an antenna rod that protrudes outward from, for example, the bonnet or trunk of a car. A high frequency active circuit 12 is provided to be directly connected to the antenna rod 11. For example, when the antenna rod 11 is installed in the rear trunk of a car, the high frequency active circuit 12 is installed in the rear trunk, and the antenna rod 11
The radio waves received by the antenna rod 11 are coupled together without going through any particular transmission circuit.

This high frequency active circuit 12 consists of an input matching circuit 13, a high frequency amplification circuit 14, and an output matching circuit 15.
The received radio signal from the antenna rod 11 is high-frequency amplified and output as a high-frequency signal from the output matching circuit 15.

The output high-frequency signal from the output matching circuit 15 is transmitted through a transmission path consisting of a coaxial cable 16, for example to the dash of the driver's seat of a car. - It is transmitted to a radio receiver 17 installed in a card or the like.

FIG. 2 is a circuit diagram specifically showing the high frequency active circuit 12. As shown in FIG.

Now, when considering the noise signal NA for the antenna rod 11 and the noise signal N for the cable 16, the noise signal NA is a noise amount that is a function of the length of the antenna 11, and the length of the antenna rod 1 is The shorter the value, the smaller the value. On the other hand, the noise signal N is
is a constant amount determined by the rotation. Looking at the magnitude relationship between the noise signals NA and N, when the antenna rod 11 is about 1 m long, "NA >NF", but when the antenna rod 11 is 50 to 60 cm, "NA medium N, J". Below that, the induced noise N of the cable 16 becomes dominant at rN, .>NA.

That is, even if the length of the antenna rod 11 is shortened, if the high-frequency active circuit 12 is directly connected to the antenna rod 1, the S of the input point C of the receiver 17 will be There is no deterioration, and the safety is substantially improved when the length of the antenna rod 11 is about 1 m. In addition, considering the degree of reduction of the noise signal NA with respect to the length of the antenna rod 11,
It has a peak of S in a state of 1yn or less.

FIG. 3 shows the experimental results of S/N with respect to the length of the antenna rod 11. The solid line is the result when the high frequency active circuit 12 is provided, and the broken line is the result when it is not present. In the case shown by the solid line, the reception performance is improved compared to the case shown by the broken line, especially when the antenna rod 11 is 50 cr.
It was confirmed that when the value was set to n or less, S was improved. In particular, the best S/N ratio can be seen at an antenna length of about 50 antennas at 76 MHz, indicated by B, and about 20 to 30 crn at 83 MHz, indicated by A. In the figure, C is 90 M
This is the case for Hz.

4 and 5 show the configuration of the antenna device section of the radio receiving device as described above.
The guide cylinder 30 is set in the rod housing 32 via the insulator 31, and the housing 32 is integrally connected to the motor housing 33 by screws or the like. There is. The antenna rod 11 has a top metal fitting 34 at its tip.
The motor protrudes from the guide tube 30, and the proximal end extends into the motor housing 33. The rod housing 32 portion passes through the vehicle's housing 35, and is connected to the grounding fitting 36 and the seat 37. The antenna device including the housings 32 and 33 is fixed to the mounting plate 35 by tightening the nut 39 through the insulator 38 across the plate 35.

Here, a sliding spring 40 that slides on the antenna rod 11 is provided inside the guide tube 30, and an insulator 31
The radio waves received by the antenna rod are transmitted to the high frequency active circuit 12 held by the antenna rod. The output signal from the cylindrical frequency active circuit 12 is taken out from the power supply plug 41 and transmitted to the receiver via a coaxial group (not shown).

A worm gear 42 is provided inside the motor housing 33, and the rotation of a motor 44 is transmitted to the worm gear 42 via a worm 43. and,
A driving pulley 45 is provided coaxially and integrally with the worm gear 42. This pulley 45 is the antenna rod 1
1, and this drive pulley 45
A driven pulley 46 is provided at a position toward the proximal end of the antenna rod 11, and an endless wire 47 is stretched between the pulleys 45 and 46.

In this case, at the connection portion where the wire 47 is made endless,
It is connected via a serially extending and contracting spring 48.4g, and the connecting part between 71'4B and 49 is a joint fitting 5° provided at the base end of the antenna rod 1. In other words, drive pulley 4 is fixed by caulking.
5 is rotated, the rotational force is transmitted to the antenna rod 11 via the spring 48.4g, and this rod 1
This allows the robot to move in a straight line in the upward or downward direction.

In the figure, 51 indicates the motor housing 3 along with the guide tube 3o.
A seal 52 prevents water from entering the antenna rod 1.
1, and the antenna rod 11 is allowed to rise until this stopper 52 hits the seal 51. Further, the lowering limit is regulated by the top metal fitting 34.

That is, by rotating the motor 44 while selecting its rotation direction, the rotation is decelerated and transmitted to the drive pulley 45, which drives the wire 47 to raise or lower the antenna rod 11. The rising end is stopped by the stopper 52 and the housing gear 53, and the descending end is stopped by the top metal fitting 34, and the spring 41 is stopped at the rising and falling ends.
1.49 The drive pulley 45, which is pulled on one side, begins to idle. Therefore, no locking force is applied to the motor 44, and no unnecessary overload condition occurs.

Incidentally, an appropriate tension is applied to the wire 47 by applying an initial tension to the springs 48 and 49.

As described above, according to the present invention, the antenna rod can be constructed from one rod-shaped body, and there is no need to make the antenna rod long. This allows you to control the expansion and contraction of the rod.
Its effectiveness as a remotely controlled automobile antenna device is remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a radio receiving device equipped with an antenna device according to an Mfi example of the present invention, FIG. 2 is a diagram showing a high frequency active circuit of the receiving device, and FIG. FIG. 4 is a cross-sectional configuration diagram of the antenna device, and FIG. 5 is a cross-sectional view taken along the line v--■ in FIG. 4. DESCRIPTION OF SYMBOLS 11... Antenna rod, 12... High frequency active circuit, 32... Rod housing, 33... Motor housing, 42... Worm gear, 43... Worm, 44... Motor, 45...・Drive pulley, 46...
- Driven pulley, 47...wire, 48.49-...spring. Applicant's agent Patent attorney Takehiko Suzue Figure 5%V ←.

Claims (1)

[Claims] A linear antenna rod is configured to be linearly movable in the axial direction so that its tip protrudes within the housing, and is connected to the high frequency amplification stage of the radio receiver. A pair of pulleys set at an interval larger than the amount of movement thereof, an endless wire stretched between the pair of pulleys, and an elastic spring connecting the wires to the antenna rod. An antenna device for an automobile, characterized in that the antenna rod is driven in a linear direction by rotationally driving the wire.