JPH05152817A - On-vehicle antenna system - Google Patents

Abstract

PURPOSE:To ensure an excellent reception sensitivity by juxtaposing an antenna wire close to a harness and an earth wire close to the harness having a length longer than the 1/2 of a wavelength of a radio wave. CONSTITUTION:In an antenna wire 4 the part including at least the entire part of an antenna 2 is arranged close to a harness 12 and the antenna wire 4 is fixed to the harness 12 at a proper interval with a tape 13.... The reception sensitivity is improved by arranging the antenna wire 4 along the harness 12. An end of a shield wire 17 of the antenna wire 4 is exposed from a sheath 18 covering the conductor and the earth wire 3 is soldered to the end. The earth wire 3 is an electric wire with a sheath and fixed to a power feeding part 1 at a proper interval with a tape 19.... Furthermore, the earth wire 3 is disposed along the harness 12 for the length of almost a half of the wavelength of the radio wave. Thus, the excellent reception sensitivity is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle antenna device provided with a harness inside a vehicle body, and more particularly to a vehicle antenna device having a simple structure to suppress the influence of the harness and improve the receiving sensitivity. It is about.

[0002]

2. Description of the Related Art Conventionally, some vehicles such as automobiles have adopted a system capable of remote control by radio so that each equipment can be operated at a position distant from the vehicle.

An example of this type of system is a so-called keyless entry system as disclosed in JP-A-60-92581. In this system, radio waves transmitted from a transmitter possessed by an operator are received by a radio receiving antenna, and locking / unlocking is performed based on the obtained signal.

[0004]

However, in the above-mentioned conventional technique, since the radio receiving antenna is used for receiving the radio wave, the obtained signal is separated into the radio signal and the keyless entry system signal in the frequency band. This requires a device to operate, resulting in high system cost. Also,
Since the signals are separated by the above device, the reliability is not satisfactory.

[0005]

In order to solve the above-mentioned problems, a vehicle antenna device according to claim 1 of the present invention is provided.
An antenna wire having a power feeding section made of a coaxial cable and a receiving section following the inner conductor exposed from the end of the power feeding section is provided, and the antenna wire is provided adjacent to a harness arranged inside the vehicle body. In addition, a ground wire is connected to the outer conductor of the power feeding unit, and the ground wire is provided adjacent to the harness having a length of ½ or more of the wavelength of radio waves.

A vehicle antenna device according to a second aspect of the present invention is the vehicle antenna device according to the first aspect, and is particularly for wireless reception used for remote control of vehicle equipment. It is characterized by being.

[0007]

In the vehicle antenna device according to the first aspect,
It was confirmed that the deterioration of the reception sensitivity was suppressed by installing the antenna wire close to the harness. Further, the reception sensitivity can be improved by providing the ground wire adjacent to the harness having the above length. This was confirmed by measuring the reception sensitivity as described later in Examples. It was also confirmed that when the ground wire is installed adjacent to a harness shorter than the above length, the reception sensitivity may be rather lowered depending on the length of the installation.

As described above, according to the above configuration, it is possible to provide an inexpensive vehicle antenna device with a simple configuration while ensuring good reception sensitivity. Therefore, by using the above-mentioned antenna exclusively for each of the receiving systems, it is possible to avoid sharing the antenna between the receiving systems, and to omit the device for separating the received signal used when the antenna is shared. You can

If the above-mentioned vehicle antenna device is used for wireless reception for remote control of vehicle equipment such as a keyless entry system as described in claim 2, the system can be constructed at low cost. it can.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a remote control receiving system will be described below with reference to FIGS.

As shown in FIG. 2, the antenna device according to the present embodiment is an antenna wire 4 including a power feeding portion 1, an antenna portion 2 and a ground wire 3, and is provided around a windshield glass 6 of a vehicle 5. It is provided. The power supply unit 1 is connected to a remote control receiving unit 8 arranged in the left fender front 7. Further, the power feeding unit 1 passes through the inside of the front pillar 9 on the passenger seat side (left side) from the receiving unit 8 and is arranged along the upper edge of the windshield glass 6 inside the roof panel 10, and on the driver side (right side). It extends near the upper end of the front pillar 11.

The antenna section 2 as a receiving section is provided with a power feeding section 1
Are arranged in a straight line in the front pillar 11 having a relatively good reception condition. Further, in order to secure the length required for reception according to the length of the wavelength of the received radio wave, an antenna unit 2 ′ longer than the front pillar 11 may be used as shown in FIG. 3, but in this case, The antenna section 2 ′ is folded back at a point within approximately 1/3 of the tip and is housed in the front pillar 11 in order to prevent a decrease in reception sensitivity.

As shown in FIG. 1, at least a portion of the antenna wire 4 including the entire antenna portion 2 is arranged close to the harness 12, and is fixed to the harness 12 with tapes 13 at appropriate intervals. ing. Thus, it was confirmed that the receiving sensitivity was improved by providing the antenna wire 4 along the harness 12. The antenna part 2 is a covered electric wire, and its core wire 14 is connected to an internal conductor core wire 15 as an inner conductor of the feeding part 1 by soldering. The inner conductor core wire 15 is covered with an insulator 16 made of polyethylene, and the insulator 16 is
It is covered with a mesh-shaped shield wire 17 as an outer conductor.

The shield wire 17 is a jacket 1 that covers the shield wire 17.
The end is exposed from 8, and the ground wire 3 is connected to this end by soldering. The ground wire 3 is a covered electric wire, and is fixed to the power feeding unit 1 with tapes 19 at appropriate intervals. Further, the ground wire 3 is arranged along the harness 12 for a length of about ½ of the wavelength of the radio wave. This is based on the following measurement results.

First, when the harness 12 is not provided along the antenna wire 4, the sensitivity ratio of the antenna wire 4 depending on the presence or absence of the ground wire 3 is as follows.
Each was measured in the range of ˜63.5 MHz. When the frequency of the radio wave is 62.76 MHz used in the keyless entry system, the receiving sensitivity when the ground wire 3 is not provided is used as a reference for comparison. As a result, as shown by the solid line in FIG. 4, the case where the ground wire 3 is provided has a slightly better sensitivity ratio than the case where it is not provided (shown by the broken line), but a significant improvement in reception sensitivity is seen. Absent.

Next, when the length of the harness 12 along the antenna wire 4 is 1/4 to 1/2 of the wavelength of the radio wave, the sensitivity ratio with and without the ground wire 3 is as described above. Each measurement was made at a range of frequencies. As a result, harness 1
If 2 is the above length, as shown by the solid line in FIG.
The sensitivity when the ground wire 3 is provided is lower than when it is not provided (shown by the broken line). It is considered that such a decrease in sensitivity is caused by the ground wire 3 receiving a radio wave of an opposite phase induced by the resonance of the harness 12.

Therefore, the harness 12 along the antenna wire 4
When the length of is equal to or more than 1/2 of the wavelength of the radio wave, the sensitivity ratios with and without the ground wire 3 were measured at frequencies within the above range. As a result, the harness 12
Is the above length, it can be seen that the reception sensitivity is significantly improved when the ground wire 3 is provided, as shown by the solid line in FIG. 6, compared to when it is not provided (shown by the broken line). ..

Therefore, the ground wire 3 has a length of approximately 1/2 or more of the wavelength of the radio wave as described above.
By being arranged along the line 2, good reception sensitivity can be secured.

As described above, according to the antenna device of this embodiment, the harness 12 is used due to the layout and the like.
When arranging the antenna wire 4 along the
The receiving sensitivity can be improved by connecting the ground wire 3 to the wire and running it along the harness 12. Further, since the antenna wire 4 has a simple structure and can be easily attached to the vehicle 5, if the antenna wire 4 is applied to a remote control receiving system such as a keyless entry system,
The system can be constructed at low cost.

[0020]

As described above, the vehicle antenna device according to the first aspect of the present invention includes the power feeding section formed of the coaxial cable and the receiving section following the inner conductor exposed from the end of the power feeding section. An antenna wire is provided, the antenna wire is provided adjacent to a harness arranged inside the vehicle body, and an earth wire is connected to an outer conductor of the power feeding section. This is a configuration in which the harness is provided adjacent to the harness having a length of ½ or more.

[0021] According to a second aspect of the present invention, there is provided a vehicle antenna device, wherein the antenna wire is applied to a wireless receiving device used for remote control of vehicle equipment.

As a result, it is possible to secure a good reception sensitivity and to provide an inexpensive vehicle antenna device with a simple structure, which can be used when a plurality of receiving systems do not need to share an antenna and share an antenna. It is possible to omit the device for separating the received signal which has been used. Therefore, if the vehicle antenna device according to the first aspect is adopted, it is possible to construct an inexpensive and highly reliable receiving system.

A vehicle antenna device according to a second aspect is the vehicle antenna device according to the first aspect,
The antenna wire is for wireless reception used for remote control of vehicle equipment.

As a result, in particular, the remote control system such as the keyless entry system can be inexpensively constructed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an antenna device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an arrangement of the antenna device of FIG. 1 in a vehicle.

FIG. 3 is a perspective view showing an arrangement in a vehicle of an antenna device in which an antenna unit is folded back.

FIG. 4 is a characteristic diagram showing the sensitivity ratio of the antenna wire depending on the presence / absence of the ground wire when the harness is not provided along the antenna wire.

FIG. 5 is a characteristic diagram showing a sensitivity ratio with and without a ground wire when the length of the harness along the antenna wire is ¼ to ½ of the wavelength of the radio wave.

FIG. 6 is a characteristic diagram showing a sensitivity ratio with and without a ground wire when the length of the harness along the antenna wire is ½ or more of the wavelength of the radio wave.

[Explanation of symbols]

 1 Feeding Part 2 Antenna Part (Receiving Part) 3 Ground Wire 4 Antenna Wire 8 Reception Unit 9 Front Pillar 10 Roof Panel 11 Front Pillar 12 Harness 14 Core Wire 15 Inner Conductor Core Wire (Inner Conductor) 17 Shield Wire (Outer Conductor)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Anan 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (2)

[Claims] 1. A harness provided with a coaxial cable, a power feeding section, and a receiving section following an inner conductor exposed from an end of the power feeding section. A ground wire is connected to the outer conductor of the power feeding unit, and the ground wire is installed close to the harness having a length of ½ or more of the wavelength of the radio wave. An antenna device for a vehicle. 2. The vehicle antenna device according to claim 1, wherein the antenna wire is for wireless reception used for remote control of vehicle equipment.