JP2007081529A - On-vehicle radio receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize cost reduction by reducing the number of parts and reducing the number of man-hour while ensuring a high antenna gain in a antenna holding mechanism of a radio receiver. <P>SOLUTION: A radio receiving circuit is formed on a printed board 12, a horizontal portion 11b of an antenna 11 to be connected to the radio receiving circuit via a power feeding pattern 15 is wired with a gap from the printed board 12, and an antenna support portion 21 provided so as to project integrally in the inner surface of a cover member 20 along the wiring route of the antenna 11 holds the antenna 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle-mounted wireless receiver, and more particularly, to a support member that securely holds a metal linear antenna mounted on a printed circuit board, and wireless communication of a remote keyless entry system for an automobile or a tire pressure monitoring system. It is used suitably for.

In-vehicle wireless receivers mounted on automobiles are provided with an antenna on a printed circuit board and connected to a wireless reception circuit formed on the printed circuit board from the viewpoints of downsizing, ease of incorporation of circuit modules, and reduction of connection cables. It is desirable.
Various types of antennas provided on the printed circuit board have been proposed, and a pattern antenna made of a printed conductor of the printed circuit board, a metal linear antenna protruding from the printed circuit board, and the like are provided.
Among these, the metal linear antenna can reduce the cost, avoids interference with the pattern formed on the printed circuit board and the electronic component to be mounted, and is a linear metal because the length is increased. It is more desirable. When this metal linear antenna is used, it is required to be arranged higher than the substrate surface in order to ensure a higher antenna gain, but an antenna holding mechanism is required to eliminate the influence of vehicle vibration.

  Japanese Unexamined Patent Publication No. 10-145121 (Patent Document 1) has been proposed as this type of in-vehicle wireless receiver. In Patent Document 1, as shown in FIG. 6, the receiver 1 engages and fixes an antenna holder 3 made of synthetic resin that is separate from the circuit board, to the circuit board 2 on which the receiving circuit is formed, The antenna 4 is held. The antenna holder 3 is formed with support grooves 3a in parallel along substantially the entire circumference of the circuit board 2, and the antenna 4 is inserted and fixed in the support grooves 3a.

  In the configuration of Patent Document 1, since the antenna holder 3 that holds the antenna 4 is retrofitted to the circuit board 2, the number of parts increases and the number of work steps increases, leading to an increase in cost. Moreover, since the space which attaches the antenna holder 3 to the circuit board 2 is needed, there exists a problem that the circuit board 2 becomes large.

In Japanese Patent Laid-Open No. 2005-45625 (Patent Document 2), as shown in FIG. 7, the printed circuit board 5 is accommodated inside the upper case 7 and the lower case 9, and the antenna 6 is integrated with the wall surface of the upper case. The end of the antenna 6 is pressed against the printed circuit board 5.
With the configuration of Patent Document 2, since the antenna is formed in the upper case, there is no need to provide a holding mechanism, but in order to provide the antenna 6 in the upper case 7, processes such as plating and vapor deposition are required, and the number of work steps is reduced. There is a problem that leads to an increase in cost.

JP-A-10-145121 Japanese Patent Laid-Open No. 2005-45625

  The present invention has been made in view of the above problems, and the holding mechanism in the case where the antenna of the wireless reception device is a metal linear antenna that is arranged so as to protrude from the substrate has a high number of parts while securing a high antenna gain. It is an object to reduce the burden on the operator by reducing the cost and reducing the work man-hours and further facilitating the single inspection of the antenna with the cover member attached.

In order to solve the above problem, in the present invention, a wireless reception circuit is formed on a printed circuit board, and a metal wire antenna connected to the wireless reception circuit via a power feeding pattern is attached.
The antenna is refracted and includes a vertical line portion at both ends and a horizontal line portion continuous between the vertical line portions at both ends, and a lower end of the one vertical line portion is connected to a feeding pattern on the printed circuit board. And the lower end of the other vertical line portion is fixed on the printed circuit board,
An antenna support is integrally projected on an inner surface of a cover material that covers the printed circuit board, and the horizontal line portion wired with a gap from the printed circuit board of the antenna is held by the antenna support. An in-vehicle wireless receiver is provided.

According to the said structure, since the antenna support part is integrally molded with the cover member, the antenna holding member made into a different body like patent document 1 becomes unnecessary, can reduce a number of parts, and can reduce an operation man-hour. Therefore, the cost can be reduced while ensuring a high antenna gain.
Further, since there is no need to provide a space for a member for holding the antenna on the printed board, the antenna can be wired to the printed board in a space-saving manner, which can contribute to downsizing of the printed board. In addition, by arranging a metal wire antenna with a gap on the printed board, the space on the printed board and the space in the vicinity of the printed board can be used effectively.
Furthermore, by integrally molding the antenna support portion and the cover member, after fixing the antenna to the cover member, the antenna can be connected to the printed circuit board by covering the cover member on the printed circuit board. Since the single antenna inspection can be easily performed, the burden on the operator can be reduced.

  The cover member is formed of a resin made of a dielectric material, and the antenna support portions are integrally formed on the inner surface of the cover member so as to protrude along the wiring path of the horizontal portion of the antenna. Is suspended to the antenna wiring position and has an antenna fitting groove or an antenna holding portion at the lower end thereof.

According to the above-described configuration, by forming the cover member with a resin made of a dielectric, it is possible to easily form even a complicated shape such as a cover member having an antenna support portion protruding.
Further, when the antenna is held by the antenna fitting groove or the antenna holding portion, the antenna can be attached to the antenna support portion with one touch, and the workability can be improved. In addition, by firmly supporting the antenna with the cover member in this way, it is possible to eliminate the influence of vehicle vibration on the antenna arranged with a gap from the substrate surface, and by changing the performance of the antenna or contacting the cover member The noise that occurs can be reduced.

Specifically, for example, the antenna support portion is configured such that a wide portion is provided at the tip of an antenna support shaft that is suspended from the inner surface of the cover, and a slit is formed from the tip of the wide portion. A circular inner fitting groove may be provided at the back end, and the antenna may be pushed into the inner fitting groove through the slit and held.
Or it is good also as a structure which consists of a pair of spring piece and the horizontal part of the said antenna is pushed in and supported between these spring pieces.

  According to the above configuration, the dipole antenna is configured by connecting the pattern antenna and the metal wire antenna in a state of being branched from the power feeding pattern, so that it is not necessary to provide a ground pattern on the printed circuit board. Therefore, it is possible to eliminate the influence of the reception performance due to the form of the ground pattern and to obtain a stable reception performance.

The metal wire antenna may be connected to a pattern antenna formed on the printed circuit board at a connection position with a feeding pattern.
According to the above configuration, since the dipole antenna is configured by connecting the pattern antenna and the metal wire antenna in a state branched from the feeding pattern, it is not necessary to provide a ground pattern on the printed circuit board. Therefore, it is possible to eliminate the influence of the reception performance due to the form of the ground pattern and to obtain a stable reception performance.
The total length of the pattern antenna and the metal wire antenna is about λ / 2 with respect to the wavelength λ of the transmission / reception wave, and the length of each of the pattern antenna and the metal wire antenna is about λ / 4. It is preferable that
In any configuration, it is preferable to form a matching circuit in the feeding pattern connected to the antenna and to perform impedance matching when the reception frequency and the antenna length do not match.

  The power feeding pattern is connected to a wireless IC mounted on a printed circuit board, the wireless IC is connected to a connector mounted on the printed circuit board, a signal processed by the wireless IC is connected to the connector, and an external device via a wire harness connected to the connector The wireless IC can receive and process a signal from an external device.

The in-vehicle wireless reception device is suitable for, for example, a device that receives a wireless signal from a remote keyless entry portable device possessed by a user or a wireless signal from a transmitter for monitoring air pressure of tires mounted on a vehicle. Can be used.
Furthermore, the vehicle-mounted antenna structure of the present invention is also suitably used as a receiver for GPS, VICS, ETC, and the like.

When receiving wireless signals from a portable device for remote keyless entry, the printed circuit board having the antenna structure is housed in a keyless receiver unit mounted in the instrument panel on the body side, It is preferable that it is large compared with the printed circuit board in the keyless receiver unit when attached to the door side.
As described above, when a printed circuit board with an antenna is accommodated in the unit on the body side, the unit itself can be enlarged, so that the printed circuit board can also have a large area and is mounted on the door side. Compared to the case where the antenna is formed on a small-sized printed circuit board mounted in a small unit, the length of the metal wire antenna is made large and about λ / 4 with respect to the wavelength λ of transmission and reception waves. Can do.

As described above, according to the present invention, since the antenna support portion is integrally formed with the cover member, it is not necessary to add an antenna holding mechanism, so that the number of parts can be reduced and the man-hour can be reduced. Therefore, the cost can be reduced.
In addition, after fixing the antenna to the cover member, the cover member can be put on the printed circuit board, and the antenna can be connected to the printed circuit board. Can be reduced.

Embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a first embodiment of the present invention.
As shown in FIG. 1, the wireless receiver 10 of the present invention has a metal wire antenna 11 mounted on a printed circuit board 12. A wireless IC 13 having a wireless receiving circuit and a connector 14 connected to the wireless IC through a pattern and connected to an external device (not shown) via a wire harness are mounted on the printed circuit board 12. .
A power supply pattern 15 having one end connected to the wireless IC 13 is provided on the printed circuit board 12, and one end of the metal wire antenna 11 and one end of the pattern antenna 18 provided on the printed circuit board are connected to the power supply pattern 15. The dipole antenna is formed by branching the metal wire antenna 11 and the pattern antenna 18 from the feeding pattern 15.
A matching circuit 16 is provided in the middle of the power feeding pattern 15.

  The printed circuit board 12 is covered and fixed with a cover member 20 formed of a resin made of a dielectric material. On the inner surface 20a of the upper wall of the cover member 20, a support portion 21 of the metal linear antenna 11 is integrally formed and protrudes downward.

The metal wire antenna 11 includes a horizontal portion 11b bent in a substantially U shape on the same plane, and two vertical portions 11a- refracted perpendicularly to the printed circuit board at both ends of the horizontal portion 11b. 1, 11a-2. The lower end of one of the vertical portions 11a-1 is inserted into a through hole formed on the printed circuit board 12 at the front end branch position of the power feeding pattern 15 and fixed by soldering, and the other vertical portion 11a- The lower end of 2 is press-fitted and fixed in a through hole formed in the printed circuit board 12.
In this attached state, the horizontal portion 11b of the metal wire antenna 11 is wired along the outer periphery of the printed circuit board 12, and is arranged with a required gap from the printed circuit board 12, and is mounted on the printed circuit board 12. The length of the metal linear antenna 11 is set to a required length without interfering with electronic components such as the above.

In order to support the metal wire antenna 11, the support portion 21 protruding from the cover member 20 protrudes at intervals along the wiring path of the horizontal portion 11 b of the antenna 11.
Specifically, as shown in FIGS. 2A and 2B, each antenna support portion 21 hangs down to the antenna wiring position in a state where the cover member 20 is covered on the printed circuit board 12, and the horizontal portion of the antenna 11. 11b is supported by the antenna support 21 from above.

  As shown in FIG. 2C, the antenna support portion 21 is provided with a wide portion 21b at the tip of an antenna support shaft 21a that is suspended from the inner surface 20a of the cover member 20. A slit 21c is formed from the tip of the portion 21b, and a circular inner fitting groove 21d (antenna fitting groove) is provided at the inner end of the slit 21c. The horizontal portion 11b of the antenna 11 is attached to the inner fitting groove 21d through the slit 21c of the antenna support portion 21 to be attached with one touch.

  The lengths of the metal wire antenna 11 and the pattern antenna 18 are set to substantially the same length, and the wavelength of the transmission / reception wave is λ, the length of the metal wire antenna 14 and the length of the pattern antenna 18 are about λ / 4 is set, and the total length of these two antennas 11 and 18 is set to be about λ / 2.

As described above, in the present invention, since the antenna support portion 21 for holding the metal wire antenna 11 is formed integrally with the cover member 20, a sufficient distance from the printed board 12 to the antenna 11 can be set. While securing a high antenna gain, the number of parts can be reduced, and the number of work steps can be reduced. As a result, the cost can be reduced.
Further, after the antenna 11 is fixed to the cover member 20, the cover member 20 can be put on the printed circuit board 12, and the antenna 11 can be connected to the printed circuit board 12. Therefore, the antenna unit including the cover member 20 can be easily inspected. This can reduce the burden on the operator.

  In the first embodiment, the shape of the horizontal portion 11b of the metal wire antenna 11 is U-shaped, but it is preferable to bend it to avoid the upper side of the heat generating electronic component mounted on the printed circuit board. It is not limited to the U-shape.

  In the first embodiment, the metal wire antenna 11 and the pattern antenna 18 are branched and connected at the tip of the feeding pattern 15 to form a dipole antenna. However, the antenna is changed to the pattern antenna 18 and attached to the connector 14. One of the terminals may be a long terminal, and the terminal antenna may be provided using the terminal as an antenna. In this case, the dipole antenna is formed by branching and connecting the terminal antenna and the metal wire antenna 11 to the tip of the feed pattern.

FIG. 3 shows a second embodiment of the present invention.
In the second embodiment, the shape of the antenna support portion 21 is different from that of the first embodiment.
A pair of antenna support shafts 21a 'is suspended from the inner surface 20a of the upper wall of the cover member 20, and the lower end of the antenna support shaft 21a' is used as a spring piece 21b '(antenna clamping portion). The insertion portion 21c ′ between the pair of spring pieces 21b ′ is held by pushing the horizontal portion 11b of the metal wire antenna 11 into the insertion portion 21c ′.
Since the configuration other than the antenna support portion 21 is the same as that of the first embodiment and the operational effects are also the same as those of the first embodiment, other explanations and operational effects are omitted.

FIG. 4 shows a third embodiment. In the third embodiment, the wireless receiver 10 of the present invention, which includes the metal wire antenna 11 of the first embodiment and supports the antenna 11 with the support portion 21 of the cover member 20, is a remote keyless entry system (RKE). ).
Specifically, a keyless receiver unit 51 including a receiving antenna that receives a radio signal from a portable device 52 possessed by a user is mounted in an instrument panel of the automobile 50.
The keyless receiver unit 51 accommodates the printed circuit board 12 shown in FIGS. 1 and 2. On the same surface side of the printed circuit board 12, the metal wire antenna 11 and the pattern antenna 18 connected to the power feeding pattern 15 are provided. A dipole antenna consisting of Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  Since the keyless receiver unit 51 is mounted in the instrument panel, the keyless receiver unit 51 can be made larger than a conventional keyless receiver unit mounted on a door. Therefore, the printed circuit board 12 accommodated in the keyless receiver unit 51 can be made larger than the printed circuit board accommodated in the unit attached to the door. Accordingly, the lengths of the metal linear antenna 11 and the pattern antenna 18 provided on the printed circuit board 12 are increased, and the total length is about λ / 4 with respect to the wavelength (λ) transmitted from the portable device 52 of the user. A margin can be formed in a length of about λ / 2.

Specifically, the frequency used for remote control in the remote keyless entry system is 300 MHz in Japan and 450 MHz in Europe.
When receiving radio waves in the frequency band of 300 MHz, the lengths of the metal wire antenna 11 and the pattern antenna 13 are set to 15 cm to 20 cm, respectively, in order to obtain the ante length with the highest reception efficiency.
When the keyless receiver unit is mounted on the body side, the printed circuit board accommodated in the unit can be enlarged, so that even when the antenna length is increased in order to receive radio waves with a frequency of 300 MHz or 450 MHz. Can respond sufficiently.

FIG. 5 shows a fourth embodiment. In the fourth embodiment, the wireless receiver of the first embodiment is used for reception from a tire pressure sensor (TPMS sensor) mounted on a vehicle tire.
More specifically, TPMS sensors 56A to 56D for detecting tire air pressure are attached to the front and rear, left and right four tires 55 attached to the vehicle 50, and detection signals from these TPMS sensors 56A to 56D are received. Receiver units 57A to 57D are mounted in a tire house near the tire. Each of the receiver units 57A to 57D accommodates a printed board having the dipole antenna of the first embodiment. The detected values of the TPMS sensors received by the receiver units 57A to 57D are connected to the air pressure monitoring ECU 59 via harnesses 58A to 58D arranged in the vehicle.

The third embodiment shown in FIG. 4 and the fourth embodiment shown in FIG. 5 employ the wireless receiver of the first embodiment shown in FIGS. 1 and 2. However, the wireless receiver of the second embodiment shown in FIG. It goes without saying that it is good.
In any of the embodiments described above, it is preferable to use a high dielectric constant material such as a glass epoxy substrate as the substrate material of the printed circuit board 12.
This is because, when the pattern antenna 18 is formed on the printed circuit board 12, when the relative dielectric constant εr of the printed circuit board increases,
(Wavelength shortening rate) = 1 / √ (dielectric constant εr)
Thus, the shortening rate is smaller than the relational expression, and the length of the pattern antenna can be shortened to a value obtained by multiplying λ / 4 by the wavelength shortening rate. Therefore, the area of the printed circuit board can be reduced by shortening the pattern antenna.

It is a disassembled perspective view which shows the radio | wireless receiver which concerns on 1st Embodiment of this invention, and the cover member has shown through the antenna support part. (A) is a schematic perspective view of the radio | wireless receiver which concerns on 1st Embodiment, (B) is sectional drawing seen from the arrow direction of (A), (C) is a principal part enlarged view of the antenna support part in (A). It is. It is a principal part enlarged view of the antenna support part which concerns on 2nd Example. It is a perspective view which shows 3rd Embodiment. It is a perspective view which shows 4th Embodiment. It is a perspective view of the receiver of a prior art example. It is a perspective view of the keyless entry receiver of other conventional examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wireless receiver 11 Metal wire antenna 12 Printed circuit board 13 Wireless IC
14 Connector 15 Power Supply Pattern 16 Matching Circuit 17 Connection Position 18 Pattern Antenna 20 Cover Member 21 Antenna Support Portion 50 Car 51 Keyless Receiver Unit 52 Portable Device

Claims (5)

A wireless receiving circuit is formed on the printed circuit board, and a metal wire antenna connected to the wireless receiving circuit via a power feeding pattern is attached.
The antenna is refracted and includes a vertical line portion at both ends and a horizontal line portion continuous between the vertical line portions at both ends, and a lower end of the one vertical line portion is connected to a feeding pattern on the printed circuit board. And the lower end of the other vertical line portion is fixed on the printed circuit board,
An antenna support portion is integrally projected on an inner surface of a cover material that covers the printed circuit board, and the horizontal line portion wired with a gap from the printed circuit board of the antenna is held by the antenna support portion. A vehicle-mounted wireless receiver.   The cover member is formed of a resin made of a dielectric, and the antenna support portions are integrally formed on the inner surface of the cover member so as to protrude along the wiring path of the horizontal line portion of the antenna. The in-vehicle wireless receiver according to claim 1, wherein the antenna is vertically extended to an antenna wiring position, and an antenna fitting groove or an antenna holding portion is provided at a lower end portion thereof.   The antenna support portion is provided with a wide portion at the tip of an antenna support shaft that is suspended from the inner surface of the cover, a slit is formed in the wide portion from the tip, and a circular inner fitting groove is formed at the back end of the slit. Provided, and the antenna is pushed and held in the inner fitting groove through the slit, or is composed of a pair of spring pieces, and the horizontal line portion of the antenna is pushed and supported between the spring pieces. The in-vehicle wireless receiver according to claim 2.   The wireless signal from the remote keyless entry portable device possessed by the user or the wireless signal from the transmitter for monitoring the air pressure of the tire mounted on the vehicle is received. The vehicle-mounted wireless receiver according to the item.   A keyless receiver for receiving a radio signal from a portable device for remote keyless entry, wherein the printed circuit board is accommodated in a keyless receiver unit, and the printed circuit board accommodated in the keyless receiver unit is attached to the door side. The in-vehicle wireless receiver according to any one of claims 1 to 3, wherein the keyless receiver unit is larger than a main printed circuit board in the unit, and is mounted on the body side.

Images