JP3485044B2 - Vehicle antenna device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention receives a signal wirelessly transmitted from a transmitter external to a vehicle body such as a tire sensor device which is mounted on a wheel and detects and wirelessly transmits information about the tire to transmit the vehicle body. The present invention relates to a vehicle antenna device that is guided to an electric circuit device provided on the side.

[0002]

2. Description of the Related Art Conventionally, as a device of this type, for example, as disclosed in Japanese Patent Laid-Open No. 10-309914,
A wiring (wire harness) for a wheel speed sensor that is connected to a wheel speed sensor that picks up the rotation of the wheel and leads to an electric circuit device is used as an antenna to detect the tire pressure of a tire that is a transmitter provided outside the vehicle body. It is known that the antenna receives the information indicating the tire pressure, which is wirelessly transmitted from the tire pressure sensor device and is guided to the electric circuit device.

[0003]

However, in the above-mentioned conventional apparatus, since the wiring for the wheel speed sensor originally transmits the pickup signal representing the wheel speed,
There is a problem that the reception sensitivity as an antenna is not very good and noise is mixed in a signal transmitted from a transmitter provided outside the vehicle body such as a tire pressure sensor device due to the pickup signal.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an antenna device for a vehicle, which has a good reception sensitivity and is less likely to contain noise.

In order to achieve the above-mentioned object, a structural feature of the present invention is that for a vehicle that receives a signal wirelessly transmitted from a transmitter outside the vehicle body and guides it to an electric circuit device provided on the vehicle body side. In the antenna device, a wire for the wheel speed sensor is provided side by side, and one end is connected to the electric circuit device, and the other end is provided in the vicinity of the wheel to provide a coaxial line. The conductor is folded back to provide a non-opposing portion at the other end of the core wire that does not face the outer conductor, and the antenna having the folded outer conductor portion as a sleeve balun is formed at the other end of the coaxial line , and the folded outer side.
The conductor is grounded to the car body . In this case, the transmitter is, for example, provided in a tire sensor device that is mounted on a wheel and detects information about a tire, and a signal wirelessly transmitted from the transmitter represents the detected information. is there. A sleeve balun is formed in a sleeve shape and is a means for converting coaxial line (unbalanced mode) and antenna (balanced mode) (Balance and unbalance).
transducer).

According to this, a sleeve balun type dipole antenna using a coaxial line is configured, and although this antenna is provided side by side with the wiring for the wheel speed sensor, it is independent, so a transmitter (for example, The sensitivity of the information wirelessly transmitted from the tire sensor device) is improved, the noise from the wheel speed sensor is less mixed, and the information from the transmitter (eg, tire sensor device) outside the vehicle body is transmitted to the electric circuit device. Supplied with high accuracy. Further, since the coaxial line is provided in parallel with the wiring for the wheel speed sensor, the antenna device can be easily assembled near the wheel with little empty space. Also, the folded back outer conductor part is
Since it is grounded to the body, the coaxial line is used for the wheel speed sensor.
Impedance caused by the current flowing through the wire even if it is attached to the wire
The change in dance can be prevented, and the receiving accuracy of the antenna device can be improved.
Will be better.

[0007]

[0008]

Another structural feature of the present invention is that the grounded position of the folded-back outer conductor portion with respect to the vehicle body is variable. According to this, even if the reception condition including the mounting state of the antenna device changes, the impedance related to the reception efficiency of the antenna can be matched.

Another structural feature of the present invention is that a ferrite core is arranged at an end of the folded outer conductor portion opposite to the folded position.
As a result, the ferrite core becomes a resistance against a high frequency signal, and the high frequency current generated in the antenna is suppressed from flowing out from the sleeve balun, and the electric wave input to the antenna can be guided to the electric circuit device without being damaged.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A vehicle antenna device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing an entire vehicle system to which the antenna device is applied. 2 is an exploded perspective view for explaining an assembled state of the antenna device.

This vehicle system includes wheels WH1 to WH.
The wheel speed sensors 11a to 11d for detecting the wheel speeds (rotational speeds) of the four wheels are provided. Wheel speed sensor 1
1a to 11d are electromagnetic pickups facing the teeth of the rotors 12a to 12d that rotate integrally with the hub 21 of the wheels WH1 to WH4, respectively, and output a pulse train signal having a period inversely proportional to the rotation speed of the wheels WH1 to WH4. The wheel speed sensors 11a to 11d are the wheel speed sensors 11a to 1d.
The wirings (wire harnesses) 13a to 13d for 1d are respectively connected to one ends, and the other ends of the wirings 13a to 13d are respectively connected to the electric circuit device 14.
The wirings 13a to 13d are for supplying the pulse train signals from the wheel speed sensors 11a to 11d to the electric circuit device 14, and in the present embodiment, the core wire is shielded by a shield wire.

Tire sensors 15a to 15d are attached to the wheels WH1 to WH4, respectively. The tire sensor devices 15a to 15d detect information on the tire 22 such as the air pressure and temperature of each tire 22 of the wheels WH1 to WH4, and wirelessly transmit the information, and are internally provided with a transmitter and an antenna. . As the used radio wave, for example, a high frequency signal of 300 MHz to 375 MHz is used. The electric waves transmitted from the tire sensor devices 15a to 15d are supplied to the electric circuit device 14 at each one end.
Antenna A formed on coaxial lines 16a to 16d connected to
It is to be received by the TN. Coaxial line 16a
16d supplies the received information about each tire 22 to the electric circuit device 14.

The electric circuit device 14 includes a wheel speed sensor 11a.
Each wheel WH1 based on the pulse train signal from
Each wheel speed of WH4 is calculated, and these wheel speeds are used for various controls such as an antilock brake device, a traction device, a vehicle attitude control device, a rear wheel steering device, and an electric power steering device. Also, the electric circuit device 1
4 detects a tire-related abnormality such as tire pressure based on the information regarding each tire 22 supplied through the coaxial lines 16a to 16d, and notifies the driver of the occurrence of the abnormality or detects the abnormality when the abnormality is detected. The occurrence of is recorded.

Next, the structure of the coaxial lines 16a to 16d, the structure of the antenna ATN provided on the coaxial lines 16a to 16d, and the method of assembling the coaxial lines 16a to 16d will be described.

As shown in FIG. 4, the coaxial wires 16a to 16d respectively include a core wire 31 made of a conductor, and an insulating portion 32 formed on the outer circumference of the core wire 31 integrally and cylindrically with an insulating material such as resin. An outer conductor 33 formed on the outer periphery of the insulating portion 32 by knitting thin conductor wires to form a net shape and a cylindrical shape, and an insulating material such as vinyl chloride provided so as to cover the outer periphery of the outer conductor 33. And the coating film 34 formed in a cylindrical shape.

In forming the antenna ATN, first, the coating film 34 at the other end of the coaxial lines 16a to 16d is provided with a length L1 (for example, 2) from the other end, which is approximately equal to a quarter wavelength of the radio wave used.
Only (00 mm to 250 mm) is peeled off (see FIG. 4 (A)). Next, the outer conductor 33, which is exposed by peeling off the coating film 34, is folded back and overlapped on the coating film 34 (see FIG. 4B). As a result, coaxial cable 1
A sleeve balun type using a coaxial line, which includes a non-opposing portion having a length L1 in the axial direction that does not face the outer conductor of the core wire 31 and the sleeve balun at the other end of 6a to 16d. The antenna ATN is formed. The length L2 of the sleeve balun in the axial direction is also substantially equal to the length L1 of the non-opposing portion of the core wire 31, that is, substantially equal to a quarter wavelength of the used radio wave.

Next, a method of assembling the coaxial wires 16a to 16d will be described. At one end of each of the wirings 13a to 13d for the wheel speed sensors 11a to 11d, as shown in FIG.
A connector 36 detachably connected to the electric circuit device 14.
And the wheel speed sensors 11a to 11d described above are respectively attached to the other ends. The electric circuit device 14 is installed in a predetermined portion of the vehicle body BD, and the wiring 1
3a to 13d are extended from the electric circuit device 14 to each wheel WH1 to WH4 along each component of the vehicle body BD. The wheel speed sensors 11a to 11d are mounted on a support member (not shown) that is provided on the vehicle body BD side and rotatably supports the hub 21, and faces the rotors 12a to 12d, respectively.

The intermediate portions of the wirings 13a to 13d for the wheel speed sensors 11a to 11d are positioned and fixed by screws 25 to an iron bracket 24 provided in the intermediate portion of the shock absorber 23 via an iron clamp 37. ing. The shock absorber 23 has a vehicle body BD at its lower end.
Is connected to a support member (not shown) for rotatably supporting the hub 21 or a lower arm, and the upper end thereof is connected to the vehicle body BD. Further, the wirings 13a to 13
Another clamp 38 is provided above the clamp 37 in FIG.
The clamp 38 is positioned and fixed at a predetermined position of the vehicle body BD. As a result, the wirings 13a to 13d for the wheel speed sensors 11a to 11d are arranged in a narrow space between the vehicle body BD and the wheels WH1 to WH4 and having movable members.

On the other hand, the connector 39 is also provided at each end of the coaxial lines 16a to 16d having the antenna ATN formed at each other end.
And the connector 39 is also detachably connected to the electric circuit device 14. Each coaxial line 16a-1
6d is the wiring 13a for the wheel speed sensors 11a to 11d.
The wheels WH1 to WH are respectively arranged along 13d.
At every four positions, the clamp 37 is crimped together with the wirings 13a to 13d to be positioned and fixed to the bracket 24 provided on the shock absorber 23, and the clamp 3
The vehicle body B is crimped together with the wirings 13a to 13d by 8
It is positioned and fixed to D.

In this case, the iron clamp 37 is positioned on the outer conductor, that is, the sleeve balun, which is provided by being folded back on the outer peripheral surfaces of the coaxial lines 16a to 16d, and the position can be changed. There is. As a result, as shown in FIG. 4 (C), the sleeve balun is attached to the vehicle body BD.
It is configured such that the distance d from the grounded position to the other end can be varied while being grounded. The wirings 13a to 13d for the wheel speed sensors 11a to 11d and the coaxial line 16a.
FIG. 3 shows a state in which .about.16d are bundled by the clamps 37 and 38.

In the embodiment constructed as described above,
The pulse train signal from the wheel speed sensors 11a to 11d is wired 1.
When supplied to the electric circuit device 14 via 3a to 13d, the electric circuit device 14 calculates each wheel speed of each wheel WH1 to WH4 on the basis of the pulse train signal, and determines these wheel speeds. It is used for various controls such as a lock brake device, a traction device, a vehicle attitude control device, a rear wheel steering device, and an electric power steering device. On the other hand, the tire sensor devices 15a to 15d are connected to the wheels WH1 to WH1.
Tire 22 such as air pressure and temperature of each tire 22 of WH4
When the information regarding the above is detected and the information is wirelessly transmitted, each antenna ATN formed on the coaxial lines 16a to 16d receives this information, and the coaxial lines 16a to 16d supply a signal representing this information to the electric circuit device 14. To do. Then, the electric circuit device 14 detects a tire-related abnormality such as tire pressure based on the information regarding each tire 22 supplied via the coaxial lines 16a to 16d. Notify the occurrence and record the occurrence of the abnormality.

In the above-described embodiment configured and operating as described above, the non-opposing portion of the core wire 31 which does not face the outer conductor 33 and the outer conductor 33 are folded back at the other ends of the coaxial wires 16a to 16d. The folded portion (sleeve balun) constitutes a sleeve balun type dipole antenna using a coaxial line, and since this antenna is independent of the wirings 13a to 13d for the wheel speed sensors 11a to 11d, the tire sensor devices 15a to 15d. The information received from the tire sensor devices 15a to 15d is transmitted to the electric circuit device 1 while the reception sensitivity of the information transmitted from the device is improved and the noise from the wheel speed sensors 11a to 11d is less mixed.
4 is supplied accurately. Also, the coaxial lines 16a to 16d
The wirings 13a to 13d for the wheel speed sensors 11a to 11d
Wheels with a small amount of free space because they are installed side by side
The antenna device can be easily assembled in the vicinity of 1 to WH4.

Further, in the above embodiment, the core wire 31
Of the non-opposing portion of the outer conductor 33 in the axial direction, and the length of the folded portion (sleeve balun) of the outer conductor 33 in the axial direction L2.
Since and are set to approximately 1/4 of the wavelength of the used radio wave, it becomes difficult for current to flow in the folded-back portion (sleeve balun), and the reception accuracy of the antenna device is further improved.
Further, since the folded-back portion (sleeve balun) is grounded to the vehicle body BD by the clamp 37 and the bracket 24, the coaxial lines 16a to 16d are connected to the wheel speed sensors 11a to 11d.
Even if the wirings 13a to 13d for d are provided side by side, the wirings 13a to 13d
It is possible to prevent a change in impedance due to a current flowing through 13d, and to improve the reception accuracy of the antenna device.

Further, the ground contact position of the folded-back portion (sleeve balun) with respect to the vehicle body BD can be varied by shifting the mounting position of the clamp 37 to change the ground contact position of the folded-back portion (sleeve balun) with respect to the vehicle body BD. it can. According to this, even if the reception condition including the mounting state of the antenna device changes, the impedance related to the reception efficiency of the antenna can be matched.

In addition, the coaxial lines 16a to 16 of the above-described embodiment.
The antenna ATN formed at the other end of d can be modified as shown in FIG. That is, the annular ferrite core 50 may be attached to the outer peripheral surface of the folded portion (sleeve balun) of the outer conductor 33 at the end opposite to the folded position. As a result, the ferrite core 50 becomes a resistance against a high frequency signal, and the antenna A
The high frequency current generated in the TN is suppressed from flowing out from the folded portion (sleeve balun), and the radio wave input to the antenna ATN can be guided to the electric circuit device 14 without impairing the reception sensitivity of the antenna ATN. It will be better.

Further, in the above embodiment, only the example in which the antenna device receives the signal wirelessly transmitted from the tire sensor device has been described. However, this antenna device is an antenna device for a keyless entry system or a beacon system. It can be widely used as an antenna device for receiving a signal wirelessly transmitted from a transmitter outside the vehicle body. That is, when the antenna device is used for a keyless entry system, a signal that is wirelessly transmitted from a transmitter outside the vehicle body and that represents information input from an input device such as a keyboard used by a user is implemented as described above. The antenna device according to the embodiment receives the signal and guides the received signal to the electric circuit device on the vehicle body side. According to this, since the antenna device is arranged outside the vehicle body, the receiving efficiency of the transmission signal transmitted from the keyless entry system is improved, and the antenna device is arranged at each of the wheels WH1 to WH4. The user can send various instructions to the vehicle from either direction of the vehicle. When the above antenna device is used for a beacon system, the antenna device receives signals indicating position information, traffic information, etc. wirelessly transmitted from a transmitter embedded in the road surface.

Further, as described above, the antenna device receives signals wirelessly transmitted from transmitters outside the vehicle body such as a keyless entry system and a beacon system in addition to the tire sensor device according to the above embodiment. In this case, by changing the used frequency (carrier frequency) variously, it is possible to avoid increasing the number of antenna devices for receiving the signals transmitted from various transmitters.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an entire vehicle system to which a vehicle antenna device according to an embodiment of the present invention is applied.

FIG. 2 is an exploded perspective view for explaining an assembled state of the antenna device.

FIG. 3 is a perspective view showing a state in which wiring for a wheel speed sensor and a coaxial wire forming an antenna are bundled together.

4A to 4C are cross-sectional views for explaining a configuration of a coaxial line and a method of forming an antenna.

FIG. 5 is a cross-sectional view showing a modified example of the antenna.

[Explanation of symbols]

WH1 to WH4 ... Wheels, ATN ... Antenna, BD ... Vehicle body, 11a-11d ... Wheel speed sensor, 12a-12d ...
Rotors, 13a to 13d ... Wiring (wire harness), 1
4 ... Electric circuit device, 15a-15d ... Tire sensor device, 16a-16d ... Antenna, 21 ... Hub, 22 ... Tire, 23 ... Shock absorber, 24 ... Bracket,
31 ... Core wire, 33 ... Outer conductor, 37, 38 ... Clamp,
50 ... Ferrite core.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takayuki Tsuchiya               Toyota City, Toyota-cho, Toyota City, Aichi Prefecture               Motor Co., Ltd.                (56) Reference JP-A-11-78447 (JP, A)                 JP-A-1-120108 (JP, A)                 JP-A-61-125205 (JP, A)                 Toshinori Tanaka, Vertical Antenna, Japan               Book, CQ Publishing Co., Ltd., March 1994               1st, separate volume CQ ham radio               March issue, 40

Claims (3)

(57) [Claims] 1. An antenna device for a vehicle, which receives a signal wirelessly transmitted from a transmitter outside the vehicle body and guides the signal to an electric circuit device provided on the vehicle body side, provided in parallel with a wiring for a wheel speed sensor, A coaxial wire is provided in which one end is connected to the electric circuit device and the other end is arranged in the vicinity of the wheel, and the outer conductor at the other end of the coaxial line is folded back to the outer conductor at the other end of the core wire. The non-opposing portions that do not face each other are provided, and the antenna having the folded back outer conductor portion as the sleeve balun is formed at the other end of the coaxial line , and
It is characterized in that the returned outer conductor part is grounded to the vehicle body.
Vehicle antenna device. 2. The vehicle antenna device according to claim 1 , wherein the grounded position of the folded back outer conductor portion with respect to the vehicle body is variable. 3. A signal wirelessly transmitted from a transmitter outside the vehicle body
Is received and guided to the electric circuit device provided on the vehicle body side.
In the vehicle antenna device, the wiring for the wheel speed sensor is installed side by side and one end is
Road device and place the other end near the wheel.
A coaxial line comprising Te provided, the other end of the core wire is folded back outside conductor of the other end of the coaxial line
It is also possible to provide a non-opposing part that does not face the outer conductor
In addition, the folded back outer conductor portion is used as a sleeve balun.
An antenna device for a vehicle , wherein the antenna is configured at the other end of the coaxial wire, and a ferrite core is arranged at an end of the folded outer conductor portion opposite to the folded position.