JP4999795B2 - Transmission path and in-vehicle communication system using the same - Google Patents

Description

  The present invention relates to a metal housing such as a vehicle, a transmission path using a conductive structure laid on the casing, and an in-vehicle communication system using the transmission path.

  A conventional in-vehicle communication system includes a portable information terminal and a communication device that are mounted on a vehicle and perform data communication with each other, a power line connected to a power source, and a cigar for connecting the portable information terminal and the communication device. The interface circuit provided in each of the portable information terminal and the communication device is connected to the power line, and the portable information terminal and the communication device send a communication signal for data communication on the signal line. The communication signal is output to the communication partner via the power line, and the communication signal from the communication partner is input via the power line. As a result, while maintaining the portability and connection convenience of the portable information terminal, the portable information terminal, the communication device, the in-vehicle device in the vehicle, etc. Communication is possible. (See Patent Document 1)

JP 2000-4305 (Claim 1, FIG. 1)

  In a conventional in-vehicle communication system, a power line is used as a communication means. Therefore, in order to establish a transmission path to a part where the power line is not wired, a new power line is connected, and the power line and the existing There has been a problem that it is necessary to provide a coupling circuit with the power source. In addition, there is a problem that man-hours related to new equipment installation are required due to the wiring of the power line.

  The present invention has been made to solve the above-described problems, and can easily establish a network with a communication terminal such as a sensor disposed in each part of a vehicle body without newly wiring for communication. An object is to obtain a transmission path and an in-vehicle communication system that can be constructed.

A transmission line according to the present invention includes a metal pipe, a structure including metal to which the metal pipe is fixed, a jig for fixing the metal pipe to the structure, and the structure and the jig. A magnetic member, and a magnetic sheet is used as the magnetic member, and the magnetic sheet is fixed by a fixture in a state of being sandwiched between the structure and the jig, The fixing tool penetrates the magnetic material sheet .

  According to the present invention, it is possible to easily use as a transmission line simply by adding a magnetic member to a conductive structure laid in a region other than a passenger compartment in a vehicle or the like, without newly performing wiring. A network with a communication terminal such as a sensor arranged in each part of the vehicle body can be easily constructed, and it is possible to reduce the weight of the vehicle body and improve the environmental performance.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a transmission line according to Embodiment 1 of the present invention. A pipe 1 such as a brake pipe is fixed to a metal surface 4 such as a body with a screw 5 by a jig 2. A magnetic member 3 having a predetermined magnetic permeability is sandwiched between the jig 2 and the metal surface 4. Since the jig 2 and the screw 5 are made of metal to give a predetermined strength, when the pipe 1 is metal, the pipe 1 and the metal surface 4 are electrically short-circuited. It becomes a composition. However, since the pipe 1 and the jig 2 are fixed to the metal surface 4 with the screw 5 penetrating the magnetic member 3, each clamp portion by the jig 2 constitutes an inductor, and the AC signal is Since it functions as reactance, it has a predetermined impedance.

  FIG. 2 is a diagram showing an equivalent circuit of the transmission line of FIG. With the configuration of the transmission path as described above, as shown in FIG. 2, the pipe 1 and the metal surface 4 are separated by the reactance 8 in each clamp portion by the jig 2. It functions as a line having a predetermined impedance with respect to the AC signal. The transmission line 51 is configured by the pipe 1, the metal surface 4, and the reactance 8 as described above. Communication terminals 9 and 10 such as sensors and controllers are connected to the transmission path 51 configured as described above. When the communication terminal 9 transmits a data signal modulated with a high-frequency AC signal, the electric signal reaches the communication terminal 10 while partially flowing in the reactance 8 through the pipe 1 and then flows on the metal surface 4 as a return path. Signal paths are formed. Through such a route, the communication terminals 9 and 10 can transmit and receive data signals to each other, and a network using the pipe 1 and the metal surface 4 is configured.

  FIG. 3 is a diagram showing an example of the frequency characteristic of the transmission line of FIG. 1, and is measured assuming that there are three clamp portions by the jig 2. The measured value includes the coupling loss. As shown in FIG. 3, the attenuation range is about 40 dB at 2.5 MHz, and an attenuation range in which a network can be configured by using a modem having a wide dynamic range such as a modem for wireless communication or power line carrier communication. Become.

  FIG. 4 is a diagram illustrating an application example of the transmission path of FIG. 1 to an in-vehicle communication system. In a region other than the passenger compartment of the vehicle 52, a front communication terminal 53 is installed at the front part of the vehicle 52, an intermediate communication terminal 54 is installed at the middle part thereof, and a rear part is installed at the rear part thereof. A communication terminal 55 is installed. The front communication terminal 53 is connected to the intermediate communication terminal 54 via the transmission path 51. The intermediate communication terminal 54 is also connected to the rear communication terminal 55 via the transmission line 51. The front communication terminal 53 and the intermediate communication terminal 54 can exchange data signals with each other via the transmission path 51. Similarly, the intermediate communication terminal 54 and the rear communication terminal 55 can transmit / receive data signals to / from each other via the transmission path 51. With such a configuration, an in-vehicle communication system that enables a network in the vehicle is constructed.

  With the above configuration, the pipe 1 and the metal surface 4 laid on the metal surface 4 can be used as a transmission line by simply sandwiching the magnetic member 3 between the jig 2 and the metal surface 4, and a new wiring is provided. Thus, it is possible to easily construct a network with communication terminals such as sensors arranged in each part of the vehicle body without implementing the above, and it is possible to reduce the weight of the vehicle body and improve the environmental performance.

As a signal application method, a method of electrically connecting the pipe 1 and the metal surface 4, a method of electrostatic coupling via a capacitance, or a method of electromagnetic induction coupling using a transformer or the like is used. Also good.
Here, an application example of electrostatic coupling to the transmission line according to Embodiment 1 will be described with reference to FIG. A conductive member 31 in which an elastic conductor material such as metal is formed in a C shape is fitted into the pipe 1. The communication terminal 9 is electrically connected to the conductive member 31 and the metal surface 4. At this time, the signal is transmitted from the contact surface between the conductive member 31 and the pipe 1 to the pipe 1, but an insulating film is formed on the surface of the pipe 1 due to oxidation of the surface of the pipe 1. The insulating film becomes a mode having a capacitance between the conductive member 31 and the pipe 1, and the conductive member 31 and the pipe 1 form a capacitor forming portion 32 and are electrostatically coupled. Further, in FIG. 5, a capacitance is provided by an insulating film between the conductive member 31 and the pipe 1, but a generally used capacitor is installed between the pipe 1 and the communication terminal 9. It is good also as a structure.
Furthermore, an application example of electromagnetic induction coupling to the transmission line according to Embodiment 1 will be described with reference to FIG. The pipe 1 is fixed on the metal surface 4 by a fixing bracket 33. A coil 34 is formed by winding an electric wire or the like around the fixing bracket 33 a predetermined N times. Both ends of the coil 34 are connected to the communication terminal 9. The coil 34 and the fixture 33 form a transformer forming part 35 constituting an N-to-1 transformer and are electromagnetically coupled. In FIG. 6, the coil 34 and the fixing bracket 33 constitute a transformer. However, instead of the coil 34 and the fixing bracket 33, a generally used transformer may be installed.

  In FIG. 2, the signal is extracted from both ends of the pipe 1. However, even if the signal is extracted from the middle of the pipe 1, the signal can be transmitted.

Embodiment 2. FIG.
FIG. 7 is a diagram showing a configuration of a transmission line according to Embodiment 2 of the present invention. A pipe 1 such as a brake pipe is fixed to a metal surface 4 such as a body with a screw 5 by a clamp member 17. A magnetic member 6 having a predetermined magnetic permeability is wound around a portion of the clamp member 17 located between the pipe support portion 17a and the metal surface 4. Since the clamp member 17 and the screw 5 are made of metal to give a predetermined strength, when the pipe 1 is made of metal, the pipe 1 and the metal surface 4 are electrically short-circuited. It becomes a composition. However, the magnetic member 6 is wound around the clamp member 17, and the clamp member 17 is fixed to the metal surface 4 by the screw 5. Since it is configured and functions as a reactance with respect to an AC signal, it has a predetermined impedance. With the configuration of the transmission path as described above, the pipe 1 and the metal surface 4 are separated by the reactance 8 in each clamp portion of the pipe 1 by the clamp member 17 as in FIG. 1 and the metal surface 4 function as a line having a predetermined impedance with respect to an AC signal. The operation of the transmission line is the same as in the first embodiment.

  With the above configuration, it is possible to use the pipe 1 and the metal surface 4 laid on the metal surface 4 as transmission lines simply by wrapping the magnetic member 6 around the clamp member 17, and the vehicle body and the like without performing new wiring. Thus, it is possible to easily construct a network with communication terminals such as sensors arranged in the respective parts, and it is possible to reduce the weight of the vehicle body and improve the environmental performance.

In FIG. 4 in the first embodiment, the transmission path according to the second embodiment can be applied to the in-vehicle communication system instead of the transmission path 51.
Further, as a signal application method, a method of electrically connecting the pipe 1 and the metal surface 4, a method of electrostatic coupling through a capacitance, or a method of electromagnetic induction coupling using a transformer or the like is used. Also good. At this time, the system similar to that shown in FIG. 5 in the first embodiment can be applied as an example of a system in which the transmission line according to the second embodiment is electrostatically coupled through the capacitance. It is. Then, as an example of the electromagnetic induction coupling method for the transmission line according to the second embodiment, the same method as that shown in FIG. 6 in the first embodiment can be applied.
In FIG. 7, signals are extracted from both ends of the pipe 1, but signals can be transmitted even if a signal is extracted from the middle of the pipe 1.

Embodiment 3 FIG.
FIG. 8 is a diagram showing a configuration of a transmission line according to Embodiment 3 of the present invention. A pipe 1 such as a brake pipe is fixed to a metal surface 4 such as a body with a screw 5 by a jig 2. An insulating member 7 having a low conductivity, such as vinyl tape, is wound around the pipe 1. Accordingly, the pipe 1 and the jig 2 are electrically separated and have a predetermined impedance.

  FIG. 9 is a diagram showing an equivalent circuit of the transmission path of FIG. With the configuration of the transmission path as described above, as shown in FIG. 9, the pipe 1 and the metal surface 4 are separated by the impedance 11 in each clamp portion by the jig 2. It functions as a transmission line in which a current path loop is formed. In this way, communication terminals 9 and 10 such as sensors and controllers are connected to the transmission path constituted by the pipe 1 and the metal surface 4. When the communication terminal 9 transmits a data signal modulated with a high-frequency AC signal, the electric signal reaches the communication terminal 10 while partially flowing in the impedance 11 through the pipe 1 and then flows on the metal surface 4 as a return path. Signal paths are formed. Through such a route, the communication terminals 9 and 10 can transmit and receive data signals to each other, and a network using the pipe 1 and the metal surface 4 is configured.

  With the above configuration, it is possible to use the pipe 1 and the metal surface 4 laid on the metal surface 4 as a transmission line simply by wrapping the insulating member 7 around the pipe 1, and the vehicle body or the like without newly performing wiring. Thus, it is possible to easily construct a network with communication terminals such as sensors arranged in the respective parts, and it is possible to reduce the weight of the vehicle body and improve the environmental performance.

In FIG. 4 according to the first embodiment, the transmission path according to the third embodiment can be applied to the in-vehicle communication system instead of the transmission path 51.
Further, as a signal application method, a method of electrically connecting the pipe 1 and the metal surface 4, a method of electrostatic coupling through a capacitance, or a method of electromagnetic induction coupling using a transformer or the like is used. Also good. At this time, as an example of a method of electrostatic coupling via a capacitance to the transmission line according to the third embodiment, the same method as that shown in FIG. 5 in the first embodiment can be applied. It is. Then, as an example of a method of electromagnetic induction coupling to the transmission line according to the third embodiment, the same method as that shown in FIG. 6 in the first embodiment can be applied.
Further, in FIG. 8, signals are taken out from both ends of the pipe 1, but transmission of signals is possible even if the signal is taken out from the middle of the pipe 1.
The insulating member 7 wound around the pipe 1 may be configured to cover a part of the pipe 1 instead of covering the entire surface, or may be divided in the longitudinal direction of the pipe 1 and arranged in parallel. You may make it the structure wound around the piping 1 in the aspect which is.

Embodiment 4 FIG.
FIG. 10 is a diagram showing a configuration of a transmission line according to Embodiment 4 of the present invention. A pipe 1 such as a brake pipe is fixed to a metal surface 4 such as a body with a screw 5 by a jig 2. Magnetic films 12 and 13 having a predetermined magnetic permeability are attached to the surface of the pipe 1 in a band shape. Magnetic materials 14 and 15 each having a coil 16 wound thereon are disposed at both ends thereof, and a closed magnetic circuit is formed on the pipe 1. As shown in FIG. 10, magnetic flux is generated inside a closed magnetic circuit composed of magnetic films 12 and 13 and magnetic materials 14 and 15 attached to the surface of the pipe 1 by a signal current generated by the communication terminal 9 or 10. To do. The communication terminals 9 and 10 can take out an induced voltage generated when the magnetic flux intersects the magnetic material 14 or 15 at the end as a signal, and exchange data with each other.

  Since the closed magnetic circuit is configured on the pipe 1 as described above, a signal transmission path can be provided on the pipe 1, and the pipe 1 can be used as a base for providing the transmission path. be able to.

Although the pipe 1 is electrically connected to the metal surface 4 via the jig 2, it does not affect the path of the magnetic flux, so there is no problem in signal transmission.
Moreover, although the piping 1 was described as being made of metal, a closed magnetic circuit made of a magnetic material is formed even if it is a non-metallic pipe, and thus can be used as a transmission line.
In FIG. 10, the transmission path including the pipe 1 according to the first embodiment is shown as a base for installing the transmission path according to the fourth embodiment, but the transmission path according to the second or third embodiment is illustrated. It is good also as a base.
In FIG. 10, signals are taken out from both ends of the magnetic films 12 and 13. However, even if the magnetic material 14 or 15 is provided in the middle of the magnetic films 12 and 13, signal transmission is possible. is there.
Further, in FIG. 4 in the first embodiment, the transmission path according to the fourth embodiment can be applied to the in-vehicle communication system instead of the transmission path 51.

It is the figure which showed the structure of the transmission line which concerns on Embodiment 1 of this invention. It is the figure which showed the equivalent circuit of the transmission line which concerns on Embodiment 1 of this invention. It is the figure which showed the example of the frequency characteristic of the transmission line which concerns on Embodiment 1 of this invention. It is a figure which shows the example of application to the communication system in a vehicle of the transmission line which concerns on Embodiment 1 of this invention. It is a figure which shows the example of application of the electrostatic coupling with respect to the transmission line which concerns on Embodiment 1 of this invention. It is a figure which shows the example of application of the electromagnetic induction coupling with respect to the transmission line which concerns on Embodiment 1 of this invention. It is the figure which showed the structure of the transmission line which concerns on Embodiment 2 of this invention. It is the figure which showed the structure of the transmission line which concerns on Embodiment 3 of this invention. It is the figure which showed the equivalent circuit of the transmission line which concerns on Embodiment 3 of this invention. It is the figure which showed the structure of the transmission line which concerns on Embodiment 4 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Piping, 2 Jigs, 3, 6 Magnetic member, 4 Metal surface, 5 Screw, 7 Insulating member, 8 Reactance, 9, 10 Communication terminal, 11 Impedance, 12, 13 Magnetic film, 14, 15 Magnetic material, 16 Coil , 17 Clamp material, 17a Pipe support part, 31 Conductive member, 32 Capacitor forming part, 33 Fixing bracket, 34 Coil, 35 Transformer forming part, 51 Transmission path, 52 Vehicle, 53 Front communication terminal, 54 Intermediate part communication terminal, 55 Rear communication terminal.

Claims (7)

Metal pipes,
A structure containing metal to which the metal pipe is fixed;
A jig for fixing the metal pipe to the structure;
A magnetic member installed between the structure and the jig;
Equipped with a,
As the magnetic member, a magnetic sheet is used,
The magnetic sheet is fixed by a fixture in a state of being sandwiched between the structure and the jig,
The transmission path , wherein the fixing tool penetrates the magnetic sheet . By electrically connecting the structure and the metal pipe, a transmission line of claim 1, wherein the transmitting the electrical signal. By electrostatically coupled to the structure and the metal pipe, a transmission line of claim 1, wherein the transmitting the electrical signal. By electromagnetic induction coupling of the structure and the metal pipe, a transmission line of claim 1, wherein the transmitting the electrical signal. Two coils,
Two magnetic materials around which the two coils are wound;
Two magnetic films attached along the longitudinal direction on the surface of the metal pipe;
With
A closed magnetic path is formed on the surface of the metal pipe by coupling one end and the other end of each of the two magnetic films with the two magnetic materials, respectively. The transmission line according to claim 1 . The transmission line according to claim 5 , further comprising a non-metallic pipe instead of the metal pipe. An in-vehicle communication system equipped with the transmission path according to any one of claims 1 to 6 .

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