JP5507949B2 - Vehicle antenna device - Google Patents

Description

  The present invention relates to a vehicle antenna device for transmitting a radio signal to a communication target such as a portable device.

  In recent years, when a driver with a portable device (electronic key) approaches the vehicle door, the vehicle door is automatically unlocked, and when the driver enters the passenger compartment, the engine can be started. So-called electronic key systems are well known. FIG. 8 schematically shows an outline of this type of electronic key system.

  As shown in FIG. 8, in this electronic key system, for example, a request signal is transmitted from the outdoor transmission device 21 provided in the vehicle door to the communication area A set around the vehicle door, and provided in the vehicle interior. The request signal is transmitted from the indoor transmission device 22 to the communication area B set in the passenger compartment. In this electronic key system, the driver has a portable device 30 that receives the request signal transmitted from the transmitting devices 21 and 22 and transmits a response signal to the received request signal. That is, when the driver carrying the portable device 30 enters the communication area A or the communication area B, a response signal is transmitted from the portable device 30. In this system, the response signal transmitted from the portable device 30 is received by the receiving device 23 provided in the vehicle compartment, and is transmitted to the vehicle control device 24 that comprehensively executes various controls relating to the vehicle. The control device 24 determines whether the driver (portable device 30) is located in the communication area A or B based on whether or not a response signal is received from the portable device 30. For example, when it is determined that the driver is located in the communication area A, the vehicle door is unlocked. For example, when it is determined that the driver is located in the communication area B, the engine is allowed to start.

  By the way, the outdoor transmitter 21 is provided with an antenna device for transmitting the request signal. Here, in such an antenna device, in addition to the configuration in which the transmission antenna is provided in the door knob of the vehicle as described above, a configuration in which the transmission antenna is provided in the door mirror, for example, has been proposed. Here, as an antenna device in which a transmission antenna is arranged inside the door mirror, for example, there is a device described in Patent Document 1. 9A and 9B show a perspective structure of the antenna device described in Patent Document 1. FIG.

  As shown in FIG. 9A, in this antenna device, a bar antenna 43 as a transmission antenna is provided at the tip of a door mirror 42 rotatably supported by a mirror bracket 41. That is, in this antenna device, when the door mirror 42 rotates from the use position shown in FIG. 9A to the storage position shown in FIG. 9B, the bar antenna 43 rotates together with the door mirror 42. It has a structure to do. Here, as shown in FIG. 10, the bar antenna 43 has a structure in which a coil 43b is spirally wound around a rod-shaped core 43a made of a magnetic material such as ferrite. Incidentally, the magnetic flux radiated from the bar antenna 43 has an 8-character shape orthogonal to the antenna axis k with the central axis of the spiral coil 43b as the antenna axis k, as shown by the solid line in FIG. Eggplant. Accordingly, the directivity in the plane parallel to the antenna axis k has a distribution that draws an ellipse around the bar antenna 43, and the directivity in the plane orthogonal to the antenna axis k is centered on the bar antenna 43. Even distribution, that is, non-directionality. As shown in FIGS. 9A and 9B, in the antenna device described in Patent Document 1, the bar antenna 43 is installed so that the direction of the antenna axis k is the vertical direction. Yes. Thereby, when the vehicle is viewed from above, the directivity of the bar antenna 43 is evenly distributed around the antenna, so even if the position of the bar antenna 43 changes as the door mirror 42 rotates, The communication area A can be maintained within a certain range.

Japanese Patent Laid-Open No. 11-32471

  Thus, if the bar antenna 43 is arranged so that the antenna axis k is in the vertical direction, even if the position of the bar antenna 43 changes as the door mirror 42 rotates, the communication area A is kept within a certain range. Will be able to maintain. However, in such an antenna device, since the request signal is radiated so as to spread in a circular shape around the door mirror 42, the communication area A illustrated in FIG. 8, that is, the door of the driver's seat or the assistant There is a situation that it is difficult to form a communication area that extends in a semicircular shape along the door of the seat.

  On the other hand, if the bar antenna 43 is installed so that the antenna axis k is parallel to the horizontal direction as shown by the two-dot chain line in FIG. The request signal is radiated so as to spread in the direction. And there exists a merit that the direction which radiated | emitted the request signal so that it may spread in the front-back direction of a vehicle in this way can form the said communication area A easily. That is, from the viewpoint of forming the communication area A, it is effective to install the bar antenna 43 so that the antenna axis k has a horizontal component, and preferably the antenna axis k is parallel to the horizontal direction. .

  However, when the bar antenna 43 is installed so that the antenna axis k has a horizontal component or the antenna axis k is parallel to the horizontal direction, the following may be a concern. That is, since the vehicle body made of a magnetic material is present near the bar antenna 43, a part of the magnetic flux radiated from the bar antenna 43 is absorbed by the vehicle body made of the magnetic material, and an appropriate communication area A is set. There is a possibility that it cannot be formed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle antenna device capable of forming an appropriate communication area even when a bar antenna is disposed on a door mirror. is there.

In order to solve the above-mentioned problem, the invention according to claim 1 is a door mirror that is rotatably supported by a mirror bracket integrally provided on a vehicle body and rotates between a use position and a storage position. In a vehicular antenna device in which a bar antenna is disposed and a radio signal is transmitted to a communication area set around a vehicle door through the bar antenna, an A pillar that supports a vehicle windshield is assembled to the windshield. The bar antenna includes a pillar and a sub-pillar that branches off from the main pillar and extends to a body portion of the vehicle door. The bar antenna has a horizontal direction component in the antenna axis direction, and the door mirror. the main pillar on the axis of the antenna axis when There are respectively positioned at the use position and the storage position location A region between the fine the sub-pillar is summarized in that comprised disposed so as not located.

As described above, when the bar antenna is disposed on the door mirror, if the bar antenna is disposed so that the direction of the antenna axis has a horizontal component, a communication area extending along the vehicle door can be easily formed. However, in this case, since a part of the magnetic flux radiated from the bar antenna is absorbed by the vehicle body made of the magnetic material, it may be impossible to secure a communication area having a necessary size. Street. Here, the inventors have found the following newly through various experiments. That is, the positional relationship between the antenna axis of the bar antenna and the vehicle body has a great influence on the formation of the communication area. In particular, when the A pillar of the vehicle is positioned on the axis of the antenna axis, the radio signal transmission area is It has been found that it is significantly smaller .

The inventors have also obtained the following knowledge through various experiments. That is, some vehicle A pillars are composed of two parts: a main pillar assembled to the windshield , and a sub pillar branched from the main pillar and extending to the body portion of the vehicle door. When the A pillar has such a configuration, it has been found that the communication area is significantly reduced when the area sandwiched between the main pillar and the sub pillar is located on the axis of the antenna axis. Therefore, as according to the above configuration, when arranging the bar antenna as a region sandwiched by the main pillar and sub-pillar on the axis of the antenna axis is not located when the door mirror is positioned respectively in the use position and the storage position location Even if the A pillar is composed of two parts of the main pillar and the sub pillar, an appropriate communication area can be formed.

The invention of claim 2 is the vehicle antenna device according to claim 1, wherein the bar antenna, when the door mirror is positioned respectively in the use position and the storage position, as well as between them both The gist is that the region sandwiched between the main pillar and the sub-pillar is not positioned on the axis of the antenna shaft when it is positioned.

  According to this configuration, an appropriate communication area can be formed even in a situation where the door mirror is moving between both of them, including the situation where the door mirror is located at the use position and the storage position. .

The invention according to claim 3 is the gist of the vehicle antenna device according to claim 1 or 2 , wherein the bar antenna is disposed so that the antenna axis is parallel to the horizontal direction. .

  According to this configuration, the communication area can be formed using the directivity of the bar antenna as much as possible, so that it is easy to form a communication area that extends along the vehicle door.

  According to the vehicle antenna device of the present invention, an appropriate communication area can be formed even when the bar antenna is disposed on the door mirror.

The top view which shows the planar structure of the vehicle by which the apparatus is mounted about one Embodiment of the antenna apparatus for vehicles concerning this invention. The side view which shows the side structure near the door of the driver's seat of the vehicle. (A) And (b) is sectional drawing which each shows the cross-sectional structure along the II-II line | wire of FIG. 2 in the state in which the door mirror is each located in a use position and a storing position. (A) And (b) is a model in which the portable device can receive the request signal transmitted from the vehicle antenna device of the embodiment in a state where the door mirror is located at the use position and the storage position, respectively. FIG. (A) And (b) is sectional drawing which each shows the cross-sectional structure along the II-II line | wire of FIG. 2 in the state in which the door mirror is each located in a use position and a storing position. (A) And (b) is a model in which the portable device can receive the request signal transmitted from the vehicle antenna device of the embodiment in a state where the door mirror is located at the use position and the storage position, respectively. FIG. Sectional drawing which shows the cross-sectional structure about the modification of the vehicle antenna apparatus concerning this invention. The top view which shows typically the outline | summary of the electronic key system of the conventional vehicle. (A) And (b) is a perspective view which shows the perspective structure about the conventional antenna apparatus for vehicles. The top view which shows the planar structure of the conventional general bar antenna.

  Hereinafter, an embodiment in which a vehicle antenna device according to the present invention is applied to a vehicle antenna device of an electronic key system will be described with reference to FIGS. The basic configuration of the electronic key system mounted on the vehicle is the same as that of the electronic key system illustrated in FIG. That is, this electronic key system is also a system that executes various controls on the vehicle by exchanging various radio signals such as a request signal and a response signal between the in-vehicle device mounted on the vehicle and the portable device. In this electronic key system, the antenna device according to the present embodiment functions as a part that transmits the request signal to the communication area A set around the vehicle door.

  First, a schematic configuration of a vehicle on which the antenna device according to the present embodiment is mounted will be described with reference to FIGS. 1 and 2. FIG. 1 shows a planar structure of the vehicle, and FIG. 2 shows a side structure near the door of the driver's seat of the vehicle. In this vehicle, the structure in the vicinity of the door of the driver's seat and the structure in the vicinity of the door of the passenger seat have a structure that is symmetrical with respect to the center line in the left-right direction of the vehicle. Only the structure near the door of the driver's seat will be described.

  As shown in FIG. 1, in this vehicle, the roof 1 of the vehicle is supported by four pillars made of a magnetic metal material such as iron, that is, the A pillar 2, the B pillar 3, the C pillar 4, and the D pillar 5. Has been. Of these pillars, the A pillar 2 that also functions as a portion that supports the windshield 6 of the vehicle is configured by two parts shown in the following (a1) and (a2).

(A1) As shown in FIG. 2, a main pillar 2 a serving as a part where a windshield 6 of a vehicle is assembled.
(A2) As shown in FIG. 2, the sub-pillar 2b is branched from the main pillar 2a and extends to the body portion 7a of the driver's door 7.

  In this vehicle, together with the main pillar 2a and the sub pillar 2b, a triangular glass 8 is fitted in a region surrounded by the vehicle body, and the visibility of the driver is secured by the triangular glass 8. Further, in the sub pillar 2b, a door glass 7b of the door 7 of the driver's seat is fitted in a portion opposite to the portion into which the triangular glass 8 is fitted. In this vehicle, the driver opens and closes the door glass 7b. At this time, the door glass 7b slides on the side of the sub pillar 2b.

  On the other hand, a mirror bracket 9 is integrally provided on the vehicle body, more specifically, on the body portion 7a of the door 7 of the driver's seat so as to be positioned below the sub pillar 2b. 10 is rotatably supported. Inside this door mirror 10, a bar antenna for transmitting a request signal is arranged in a communication area set around the door 7 of the driver's seat, that is, an area indicated by a one-dot chain line in FIG. Yes.

Next, the structure of this door mirror 10 will be described in detail with reference to FIGS. FIGS. 3A and 3B show a cross-sectional structure along the line II-II in FIG.
As shown in FIG. 3A, the door mirror 10 is mainly composed of a hollow rectangular parallelepiped housing 11 having an opening on a side surface, and a mirror portion 12 fitted into the opening of the housing 11. Yes.

  Here, the base end portion in the longitudinal direction of the housing 11 is rotatably supported by a columnar shaft portion 10a formed on the mirror bracket 9, and the housing 11 is rotated by the power of a motor (not shown). It has a structure that rotates around n. That is, as the housing 11 rotates, the position of the entire door mirror 10 shown in FIG. 3A, that is, the usage position where the door mirror 10 protrudes from the door 7 of the driver's seat is shown in FIG. 3B. And a retracted position that is in a state along the door 7 of the driver's seat.

  On the other hand, a bar antenna 13 is disposed inside the housing 11 so that the antenna axis m is orthogonal to the axis n, in other words, the antenna axis m is parallel to the horizontal direction. Incidentally, the basic configuration of the bar antenna 13 has the same structure as that of the bar antenna illustrated in FIG. 10, and a coil is spirally wound around a rod-shaped core made of a magnetic material such as ferrite. It consists of a rotated structure. Incidentally, if the bar antenna 13 is arranged in such a manner that the antenna axis m is parallel to the horizontal direction, a communication area can be formed using the directivity of the bar antenna 13, and therefore the door 7 of the driver's seat is used. As described above, it is easy to form the communication area A extending along the line.

  By the way, when the bar antenna 13 is arranged so that the antenna axis m is parallel to the horizontal direction, a part of the magnetic flux radiated from the bar antenna 13 is absorbed by the vehicle body made of a magnetic material, It becomes difficult to form the communication area A illustrated in FIG. Here, the inventors have found the following newly through various experiments. That is, the positional relationship between the antenna axis m of the bar antenna 13 and the vehicle body has a great influence on the transmission area of the request signal. In particular, the main pillar 2a and the sub pillar 2b are sandwiched on the axis of the antenna axis m of the bar antenna 13. It was newly found that the transmission area of the request signal is greatly reduced when the area is located.

  Next, contents newly found by the inventors will be described with reference to FIG. 3 and FIGS. Note that the inventors experimentally measured an area where the portable device could actually receive the request signal when the request signal was transmitted from the bar antenna 13, and FIGS. In FIGS. 6A and 6B, the outer edge of the receivable area C measured in the experiment is indicated by a two-dot chain line. 4 (a) and 4 (b) and FIGS. 6 (a) and 6 (b), for convenience, only the communication area A set around the door 7 of the driver's seat is shown by a one-dot chain line. The communication area set around the door is not shown.

First, as shown in FIGS. 3A and 3B, the case where the bar antenna 13 is arranged so that the antenna axis m is parallel to the longitudinal direction of the housing 11 will be described.
At this time, as shown in FIG. 3A, in a state where the door mirror 10 is located at the use position, an area sandwiched between the main pillar 2a and the sub pillar 2b on the axis of the antenna axis m of the bar antenna 13 Is located. On the other hand, as shown in FIG. 3B, when the door mirror 10 moves from the use position to the retracted position, the area sandwiched between the main pillar 2a and the sub pillar 2b is not positioned on the axis of the antenna axis m of the bar antenna 13. It becomes like this. Then, as a result of measuring the receivable area C when the door mirror 10 is located at the use position and the storage position in such a configuration, the measurement results as shown in FIGS. 4A and 4B are obtained. Obtained.

  That is, as shown by a two-dot chain line in FIG. 4A, when the door mirror 10 is located at the use position, the receivable area C is the door of the driver's seat from the front of the vehicle centering on the door mirror 10. It became an area spreading in a semicircular shape including the vicinity of 7. However, in this case, an area in which the request signal cannot be received by the portable device is formed in the communication area A, and an appropriate communication area A cannot be formed. On the other hand, as shown in FIG. 4B, when the door mirror 10 is located at the retracted position, the receivable area C is halfway including the door of the rear seat from the front of the vehicle around the door mirror 10. It became an elliptical area. In this case, the portable device can receive a request signal at an arbitrary position in the communication area A, and an appropriate communication area A can be formed.

  As described above, when the bar antenna 13 is arranged so that the antenna axis m is parallel to the horizontal direction, a region sandwiched between the main pillar 2a and the sub pillar 2b is located on the axis of the antenna axis m of the bar antenna 13. It can be seen that the transmission area of the request signal is greatly reduced.

  Therefore, in this embodiment, when the door mirror 10 moves between the use position and the storage position, the bar antenna 13 is placed so that the region sandwiched between the main pillar 2a and the sub pillar 2b is not located on the axis of the antenna axis m. I try to arrange it.

  Specifically, as shown in FIGS. 5A and 5B, the bar antenna 13 is arranged so that the antenna axis m faces the front of the main pillar 2a. As a result of measuring the receivable area C when the door mirror 10 is located at the use position and the storage position in such a configuration, the measurement results as shown in FIGS. 6A and 6B are obtained. Obtained.

  That is, as shown in FIGS. 6 (a) and 6 (b), the receivable area C includes the door mirror 10 regardless of whether the door mirror 10 is in the use position or the storage position. It became an area that spreads out in a semi-elliptical shape from the front of the vehicle, including the door of the rear seat. In this case, the portable device can receive a request signal at an arbitrary point in the communication area A, and an appropriate communication area A can be formed. Therefore, according to the vehicle antenna device of the present embodiment, an appropriate communication area A can be formed even when the antenna axis m is arranged parallel to the horizontal direction.

As described above, according to the vehicle antenna device according to the present embodiment, the following effects can be obtained.
(1) When the bar antenna 13 is arranged inside the door mirror 10, when the door mirror 10 is located at the use position and the storage position, and between the both, it is on the axis of the antenna axis m. The bar antenna 13 is arranged so that the region sandwiched between the main pillar 2a and the sub pillar 2b is not located. As a result, even in a situation where the door mirror 10 is moving between both the use position and the storage position, the appropriate communication area A can be formed.

  (2) The bar antenna 13 is disposed so that the antenna axis m is parallel to the horizontal direction. Thereby, since the communication area A can be formed using the directivity of the bar antenna 13 to the maximum, the communication area A can be easily formed.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, the bar antenna 13 is arranged so that the region sandwiched between the main pillar 2a and the sub pillar 2b is not located on the axis of the antenna axis m. In addition to this, as shown in FIG. The bar antenna 13 may be disposed in the vicinity of the tip of the door mirror 10. By adopting such a configuration, the bar antenna 13 can be separated from the A pillar 2, so that the magnetic flux radiated from the bar antenna 13 is hardly absorbed by the A pillar 2, thereby forming a wider communication area. Will be able to.

  In the above embodiment, the bar antenna 13 is arranged so that the antenna axis m forms an angle of “45 °” with the longitudinal direction of the housing 11. For example, as shown in FIG. In addition, the bar antenna 13 may be arranged so that the antenna axis m is orthogonal to the longitudinal direction of the housing 11. In short, if the bar antenna 13 is arranged so that the region sandwiched between the main pillar 2a and the sub pillar 2b is not located on the axis of the antenna axis m when the door mirror 10 moves between the use position and the storage position. Good.

  In the above embodiment, the bar antenna 13 is arranged so that the antenna axis m is parallel to the horizontal direction. However, the bar antenna 13 is arranged so that the direction of the antenna axis m has at least a horizontal component. May be. Even in the vehicular antenna device including the bar antenna 13 arranged in this way, the main pillar 2a and the sub-pillar 2b are arranged on the axis of the antenna axis m when the door mirror 10 moves between the use position and the storage position. Arranging the bar antenna 13 so that the sandwiched area is not located is effective in forming a communication area that extends along the vehicle door.

  In the above embodiment, when the door mirror 10 moves between the use position and the storage position, the bar antenna 13 is arranged so that the region sandwiched between the main pillar 2a and the sub pillar 2b is not located on the axis of the antenna axis m. I tried to do it. Instead, for example, as illustrated in FIG. 3 above, when the door mirror 10 is located at the retracted position, an area sandwiched between the main pillar 2a and the sub pillar 2b is not located on the axis of the antenna axis m. A bar antenna 13 may be arranged. Employing such a configuration is also effective in forming an appropriate communication area A when the door mirror 10 is located at the storage position. Note that the bar antenna 13 may be arranged so that the region sandwiched between the main pillar 2a and the sub pillar 2b is not located on the axis of the antenna axis m when the door mirror 10 is located at the use position.

In the above embodiment, the vehicular antenna apparatus according to the present invention is mounted on a vehicle in which the A pillar 2 is composed of the main pillar 2a and the sub pillar 2b. Instead of this, for example, only one A pillar is used. It is also possible to mount the vehicle antenna device according to the present invention on a vehicle. In this case, the bar antenna 13 may be arranged so that the A pillar is not located on the axis of the antenna axis m when the door mirror 10 is located at either the use position or the storage position.
(Appendix)
Next, a technical idea that can be grasped from the above embodiment and its modifications will be additionally described.

(B) pre-SL bar antenna, vehicle antenna apparatus characterized by comprising been arranged close to the distal end of the door mirror. According to this configuration, since the bar antenna can be separated from the A pillar, the magnetic flux radiated from the bar antenna is hardly absorbed by the A pillar. For this reason, a wider communication area can be formed.

(B) the provided a vehicle antenna device, there at the vehicle electronic key system for various vehicle control is executed by the vehicle-mounted device by transmitting and receiving radio signals with the in-vehicle device mounted on a vehicle and the portable device An electronic key system for a vehicle, wherein the vehicle antenna device is used as a portion for transmitting the radio signal from the in-vehicle device. As described above, in an electronic key system for a vehicle, in recent years, it has been proposed to arrange a transmission antenna for transmitting a radio signal on a door mirror. For this reason, it is significant to use the vehicle antenna device according to claims 1 to 3 and appendix a for an electronic key system of a vehicle.

  A, B ... Communication area, C ... Receivable area, k, m ... Antenna axis, n ... Axis, 1 ... Roof, 2 ... A pillar, 2a ... Main pillar, 2b ... Sub pillar, 3 ... B pillar, 4 ... C Pillar, 5 ... D pillar, 6 ... Windshield, 7 ... Door, 7a ... Body part, 7b ... Door glass, 8 ... Triangular glass, 9, 41 ... Mirror bracket, 10, 42 ... Door mirror, 10a ... Shaft part, 11 ... Housing, 12 ... Mirror part, 13, 43 ... Bar antenna, 21 ... Outdoor transmitter, 22 ... Indoor transmitter, 23 ... Receiver, 24 ... Vehicle controller, 30 ... Portable machine, 43a ... Core, 43b ... Coil .

Claims (3)

A bar antenna is arranged on a door mirror that is pivotally supported by a mirror bracket provided integrally with the vehicle body and rotates between a use position and a storage position, and is set around the vehicle door through the bar antenna. In the vehicle antenna device that transmits a radio signal to the communication area,
A pillar supporting the windshield of the vehicle is composed of a main pillar assembled to the windshield, and a sub pillar branched from the main pillar and extending to the body portion of the vehicle door,
The bar antenna, and the direction of the antenna axis is to have a horizontal component, the main pillar on the axis of the antenna axis when the door mirror is positioned respectively at the use position and the storage position location The vehicle antenna device is arranged such that a region sandwiched between the sub-pillars is not located. The bar antenna is sandwiched between the main pillar and the sub-pillar on the axis of the antenna axis when the door mirror is located at the use position and the storage position, respectively , and between them. The vehicular antenna device according to claim 1 , wherein the vehicular antenna device is arranged such that a region to be mounted is not located. The bar antenna for a vehicle antenna device according to claim 1 or 2, wherein the antenna axis is disposed in parallel to the horizontal direction.

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