JP2009126286A - On-vehicle junction box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle junction box capable of easily specifying an electronic control unit with an abnormality occurring therein out of a plurality of electronic control units connected to an internal circuit of the junction box and a CAN communication line. <P>SOLUTION: In the on-vehicle junction box storing an internal circuit for branch connection in a case, a printed circuit board having a circuit for branch connection to a plurality of electronic control units forming nodes of the CAN communication via a CAN communication line is stored as the internal circuit. A checking switch for switching the connection/disconnection of the circuit during the abnormality check of the connected electronic control unit is provided in each branch circuit of the printed circuit board. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle junction box, and more specifically, to identify an electronic control unit in which an abnormality has occurred among a plurality of electronic control units connected to the junction box via a CAN communication line. It is.

An automobile is equipped with a junction box that concentrates branch connections to electrical components installed in the passenger compartment, and the power supply circuit, ground circuit, and signal circuit are branched and connected inside the junction box. Are connected to each other via a wire harness.
Recently, a large number of electronic control units (ECUs) are mounted in an automobile, and these electronic control units are automatically controlled by being connected to electrical components via a CAN communication circuit. In many cases, the electronic control unit is connected to the junction box via a joint connector, which is a branch connection component. However, an electronic control unit and a branch connection circuit serving as a CAN communication node inside the junction box. May be included.

  As a device using the joint connector, for example, Japanese Unexamined Patent Application Publication No. 2006-12592 (Patent Document 1) provides a centralized branch network system. As shown in FIG. 6, this centralized branch network system connects nodes 2 to a plurality of branches branched from a joint connector 1, and transmits / receives data to / from each node 2 via a transmission path 3. Controls the electrical equipment installed in the vehicle.

At the joint part of the joint connector, it is checked whether or not an abnormality has occurred in the electronic control unit that is a node of a large number of CAN communication arranged in the automobile and the CAN communication circuit connected to each of these nodes. In this case, in a state where all nodes are connected, it is not possible to specify which CAN communication circuit has an abnormality.
Therefore, in the centralized branch network system of Patent Document 1, in order to identify the node 2 in which an abnormality has occurred, the connection terminals of the transmission line 3 connected to the node 2 are separated from the joint connector 1 one by one. There is a problem that it must be inspected and requires a lot of work.
In order to identify the node where an abnormality has occurred, it has been proposed to attach an individual connector for each node so that the connector can be inserted and removed for each node so that the joint can be separated. There is a problem that the joint connector is increased in cost and size.

Furthermore, it is necessary to converge the power line and the ground line together with the signal line from the junction box to the joint connector and from the joint connector to each node 2.
Therefore, it is necessary to separate the signal line from the power supply line and the ground line, and to provide a joint connector composed only of the signal line, which causes a problem of complicated wiring.

JP 2006-12492 A

  The present invention has been made in view of the above problems, and among the electronic control units connected via the CAN communication circuit, the electronic control unit in which an abnormality has occurred can be easily identified without cost. In addition, it is an object to provide an in-vehicle junction box that can be easily configured.

In order to solve the above problems, the present invention is an in-vehicle junction box containing an internal circuit for branch connection in a case,
As the internal circuit, a printed circuit board provided with a circuit for branching connection with a plurality of electronic control units serving as CAN communication nodes via a CAN communication line is accommodated.
An in-vehicle junction box is provided, wherein each branch circuit of the printed circuit board is provided with a check switch capable of switching connection / disconnection of a circuit when checking the abnormality of the connected electronic control unit. is doing.

As described above, in the present invention, a circuit for branch connection with a plurality of electronic control units that are CAN communication nodes is provided on a printed circuit board in a junction box via a CAN communication line, and connected to each node. The power supply line and the ground line are converged and wired. That is, the joint connector interposed between the junction box and each node is eliminated.
Since each branch circuit of the printed circuit board in the junction box is provided with a check switch that can switch connection / disconnection of the circuit when checking the abnormality of the connected electronic control unit, the connected electronic By switching connection / disconnection of the circuit when checking the abnormality of the control unit, the electronic control unit in which the abnormality has occurred can be specified.
Specifically, for example, when an abnormality occurs in the ECU and a warning is displayed, if the warning display disappears when the circuit is cut by turning off the check switch, an abnormality occurs in the electronic control unit that is turned off. Will be. On the other hand, if the warning display is kept, it can be determined that no abnormality has occurred in the electronic control unit that is turned off.
In this way, the electronic control unit in which an abnormality has occurred can be identified by simply turning off the check switches for the branch circuit connected to the electronic control unit via each CAN communication line.

  In addition, since a branch circuit for connecting to each electronic control unit via CAN communication is formed on a printed circuit board accommodated in the junction box, a joint connector for branch connection of the CAN communication circuit is not necessary, and a power source There is no need to branch and wire the line and the CAN communication line, the wiring route can be unified, the amount of wires to be wired can be reduced, and the configuration of the wire harness can be simplified. Therefore, the entire automobile can be reduced in weight and the cost can be reduced.

The check switch is preferably provided so as to be exposed on the outer surface of the case, and the check switch can be connected and disconnected by connecting and disconnecting the check switch from the outside.
As described above, when checking the abnormality of the electronic control unit, the electronic control unit can be removed by inserting / removing the check switch provided in the branch circuit of the printed circuit board from the outside of the case without removing the junction box from the installation position. The branch circuit connected via the CAN communication line can be connected and disconnected to identify the electronic control unit in which an abnormality has occurred.

  The check switch is provided in a filter circuit in which a coil and a resistor formed in each branch circuit are connected in parallel, and an electrical component that connects the coil and the resistor in parallel is connected and disconnected from the outside. -It is preferable to be able to cut.

When the CAN communication circuit is branched, the communication waveform is distorted due to impedance mismatching, so that it is necessary to limit the wire wiring. By providing a filter circuit in the check switch, it is not necessary to provide a separate filter circuit on the CAN communication circuit, and signal reflection due to impedance mismatch can be attenuated.
In addition, it is preferable that the impedance of the trunk line and the branch line in the branch part of the communication circuit is 6 to 50%, preferably 10 to 22%, of the bus impedance of the communication circuit to be used.
If the impedance is 6% or more, the reflection of the signal at the branching portion of the communication circuit can be attenuated.

It is preferable that an ECU abnormality check portion in which all of the check switches are centrally arranged at one place is provided on the outer surface of the case so that the check switch can be switched from the outside.
The check switch provided in the junction box is branched by the branch circuit of the printed circuit board in the junction box, and corresponds to the number of electronic control units that are branched and connected via the CAN communication line, for example, about 20 are provided. Many check switches are concentrated in one place.
In this way, by centrally arranging the check switches in one place, when checking abnormal electronic control units, all electronic control units can be checked in one place. Can be improved.

It is preferable that the ECU abnormality check part is disposed adjacent to a fuse housing part provided on the outer surface of the case so that switching can be performed through a maintenance opening for fuse replacement.
Since the fuse housing part is located at a position where it can be operated from the outside during maintenance, if the switch mounting part for check is placed at a position close to the fuse housing part, it can be visually observed from the outside as during maintenance. Work can be done.
Normally, the junction box is placed in the trim at the front lower part of the driver's side of the vehicle's instrument panel, and the fuse installed in the junction box is replaced by opening the maintenance opening cover formed in the trim. An exchange has been made. Therefore, if the ECU abnormality check unit is arranged at a position corresponding to the maintenance opening, an abnormal electronic control unit can be specified through the maintenance opening.

Instead of providing a check switch in the middle of a branch circuit branched by a printed circuit board, a fuse may be provided in a power supply branch circuit connected to each electronic control unit, and the fuse may be used as a check switch. That is,
As an internal circuit of the junction box, a printed circuit board provided with a circuit for branching connection with a plurality of electronic control units serving as CAN communication nodes via a CAN communication line, and a bus bar are housed.
A power branch circuit that individually supplies power to the plurality of electronic control units is provided on the printed circuit board or the bus bar, and a fuse present on the power branch circuit is used as a check switch when checking the abnormality of the electronic control unit. And switching between connection / disconnection of the circuit and circuit connection / disconnection.

  As described above, whether or not an abnormality has occurred in each electronic control unit by disconnecting the power supply circuit connected to the electronic control unit by removing the fuse provided in each branched power supply circuit Can be detected to identify the electronic control unit in which an abnormality has occurred.

  The CAN communication line is concentrated in an electric wire group of an instrument panel harness, an engine room harness, a floor harness, a door harness, and / or a roof harness that is connected to the internal circuit material, and is routed in the vehicle.

  In the present invention, the CAN communication line can be formed from the junction box together with the power supply line and the ground line as a wire harness and can be connected to each electronic control unit. Only the CAN communication line need not be separated from the power supply line and the ground line and wired to the automobile, and the wiring harness can be easily wired.

As described above, according to the present invention, as an internal circuit of a junction box mounted on an automobile, a print provided with a circuit for branching connection with a plurality of electronic control units serving as CAN communication nodes via a CAN communication line is provided. Each electronic control unit is provided with a check switch that accommodates the board and can switch connection / disconnection of the circuit when checking the abnormality of the connected electronic control unit in each branch circuit of the printed circuit board. By operating the connected check switch and disconnecting the circuit, the node where the abnormality has occurred can be identified.
Therefore, there is no need to provide a junction connector on the CAN communication line connecting the junction box and the electronic control unit, and the CAN communication line is converged as a single wire harness and routed in the automobile. Can do. As a result, the number of wire harnesses arranged in the entire automobile can be reduced, and the number of parts can be reduced, so that weight reduction and cost can be reduced.

  Further, if a filter circuit is provided in the check switch interposed in the CAN communication branch circuit on the printed circuit board, it is not necessary to provide a separate filter circuit on the CAN communication circuit, and attenuation of signal reflection due to impedance mismatch is attenuated. be able to.

  Further, when the check switches provided in each branch circuit are centrally arranged at one place and are exposed on the outer surface of the case adjacent to the fuse housing portion, the check switches are externally provided through the maintenance openings. By operating it, you can easily check the node abnormality.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show a first embodiment of the present invention.
The junction box 10 of this embodiment is arrange | positioned inside the trim 50 of the lower front forward under the driver's seat of a motor vehicle, as shown in FIG. The junction box 10 is supplied with power from a battery mounted in the engine room, and a power supply circuit, a ground circuit, and a signal circuit connected to an electrical component mounted in the vehicle interior are intensively connected by a circuit housed in the junction box. ing.
The circuit branched in the junction box is connected to an instrument panel harness 61, a floor harness 62, an encoder harness 63, and a group of wires constituting a room harness and a door harness (not shown).

As shown in FIG. 2, the junction box 10 accommodates a laminated body 13 in which a bus bar 13a and an insulating plate 13b are laminated as the internal circuit inside a case constituted by an upper case 11 and a lower case 12. A printed circuit board 14 is disposed below the laminated body 13, and a spacer 15 is disposed between the upper surface side of the printed circuit board 14 and the lower surface of the laminated body 13.
An opening 11a is provided on one side surface of the upper case 11 so as to face the fuse housing portion 16 and the ECU abnormality check portion 17, and the opening 11a is provided in the trim 50 as shown in FIG. It arrange | positions toward the opening 50a for maintenance. The maintenance opening 50a is opened and closed by a cover 50b.

As shown in FIG. 3, a branch circuit 30 connected to a plurality of electronic control units 70 (hereinafter referred to as ECU 70) is provided on the conductor of the printed circuit board 14 accommodated in the case of the junction box 10. The branch circuit 30 connected to each ECU 70 has a CAN communication branch circuit 31 connected via the CAN communication line 21, a power supply branch circuit 32 connected via the power line 22, and a ground branch connected via the ground line 23. The circuit 33 is provided. Since the CAN communication branch circuit 31 is connected to a CAN communication line composed of a twisted pair electric wire, it forms a pair of CAN communication branch circuits.
Only the CAN communication branch circuit 31 may be provided on the printed circuit board 14, and the power branch circuit and the ground branch circuit connected to the ECU 70 may be formed by the bus bar.

  Each terminal 18a solder-connected to the conductors of the CAN communication branch circuit 31, the power supply branch circuit 32, and the earth branch circuit 33 connected to one ECU 70 is inserted into a through hole provided in one terminal holding base 18 mounted on the printed circuit board 14. It protrudes through.

  The ECU abnormality check unit 17 including a check switch 40 is attached to one side of the printed circuit board 14. The ECU abnormality check unit 17 is positioned below the fuse housing unit 16 with the junction box 10 assembled, exposed to the opening 11a, and closed by the cover 50b of the maintenance opening 50a of the trim 50 as described above. When the cover 50b is opened, it can be operated from the outside.

  The check switch 40 is interposed in the CAN communication branch circuit 31 provided on the printed circuit board 14 between the branch point and the connection end of the connector connection terminal connected to the load side terminal. ing.

As shown in FIG. 3, the ECU abnormality check unit 17 has a housing 17a mounted on one side of the printed circuit board 14, and a plurality of switch housing chambers 17b arranged in parallel to the housing 17a. All the check switches 40 are detachably attached. These check switches 40 are configured to be inserted and removed from the side of the printed circuit board 14.
Since the CAN communication line 21 connected to each ECU (electronic control unit) 70 is formed of a twisted pair electric wire, a pair of CAN communication branch circuits connected to each twisted pair electric wire can be connected and disconnected.

In each of the switch accommodating chambers 17b, each of the CAN communication branch circuits 31 is divided at the side end of the printed circuit board 14, and the tuning fork terminals 19a and 19b that are solder-connected at the divided positions are projected.
On the other hand, as shown in FIG. 4, the check switch 40 is provided with terminal fittings 41 having terminal portions 41a and 41b fitted and connected to the tuning fork terminals 19a and 19b at both ends, and the terminal portions 41a and 41b. The coil 41c and the resistor 41d are connected in parallel through a filter circuit. When the check switch 40 is inserted and attached, the divided CAN communication branch circuit 31 is connected and conducted, and when the check switch 40 is removed, the CAN communication circuit is disconnected.

The bottom wall 12a of the lower case 12 is provided with a plurality of connector housing portions 12b into which the connectors 64 to 66 of the harnesses 61 to 63 are fitted. The connector accommodating portions 12b project the ECU connection terminals 18a held and projected by the terminal holding base 18 of the printed circuit board 14, and the terminals projecting from the bus bar 13 are also projected.
The wire harnesses 61 to 63 for fitting the connector housing portions 12b and the connectors 64 to 66 are formed by converging the CAN communication line 21, the power supply line 22, and the ground line 23.

Next, an abnormality check method for the ECU will be described.
When a malfunction occurs in any of the ECUs 70 and the warning lamp is lit, the cover 50b of the vehicle trim 50 is opened, a hand is inserted through the maintenance opening 50a, and the check switch 40 connected to the instrument panel harness 21 is first used. Is removed from the switch accommodating chamber 17b.
When the check switch 40 is pulled out, the communication circuit to the ECU 70 is disconnected. Therefore, when the ECU 70 is abnormal, the warning lamp is turned off. On the other hand, when there is an abnormality in the other ECU 70, the communication circuit to the ECU 70 where the abnormality has occurred is still connected, so the warning lamp remains lit. In this manner, by connecting and disconnecting the CAN communication branch circuit 31 by inserting and removing the check switch 40, it is possible to identify which ECU 70 has an abnormality.

  As described above, in the present invention, the check switch 40 interposed in each CAN communication branch circuit 31 connected to each ECU 70 is sequentially removed from the switch housing chamber 17b, and the CAN communication branch circuit is disconnected. It is possible to easily specify whether the ECU 70 connected to the CAN communication circuit is abnormal.

  In the present invention, since the CAN communication branch circuit 31 is formed on the printed circuit board in the junction box 10, there is no need to provide a joint connector on the CAN communication line, and the CAN communication line 21 is connected to the power supply line 22 and the ground line 23. And can be connected to the electronic control unit 70 and wired as one wire harness.

Further, since the ECU abnormality check portion 17 provided in the junction box is disposed opposite to the maintenance opening 50a of the trim cover 50 and the check switches 40 are centrally arranged at one place, the check switch 40 is visually observed. The switching work can be performed, and all the ECUs 70 can be checked in one place, so that the work efficiency can be improved.
Furthermore, by providing the filter circuit 41 in the check switch 40 for detecting the abnormal ECU, it is not necessary to provide a separate filter circuit on the CAN communication circuit, and the reflection of the signal at the branch portion of the communication circuit can be attenuated. .

  In the first embodiment, the filter circuit is provided in the check switch 40. However, the filter circuit may be provided in a CAN communication branch circuit on the printed circuit board separately from the check switch. In that case, the check switch 40 may be a switch including a terminal fitting that is detachably connected to the divided CAN communication branch circuit.

FIG. 5 shows a schematic diagram of the second embodiment.
In the second embodiment, a power branch circuit 32 connected to each ECU 70 via a power line is provided in the bus bar 13a, and a fuse 80 is interposed in the middle of the power branch circuit 32 of each bus bar. Arranged in the accommodating portion 16.
Similarly to the first embodiment, the terminal 13b provided at the load-side terminal of the power branch circuit 32 with the fuse 80 is projected into the connector housing portion 12b, and the power line connected to each ECU 70 and the connector 68 are fitted. is doing.

  As described above, the fuse 80 is provided in each power supply branch circuit connected to each ECU 70. When the fuse 80 is removed, power is not supplied to the ECU 70. The display disappears, and it can be specified that the ECU is an abnormal ECU.

1A is a perspective view showing the arrangement of a junction box, and FIG. 1B is a cross-sectional view showing the positional relationship between a maintenance opening and a junction box. It is a disassembled perspective view of a junction box. (A) is a perspective view which shows a printed circuit board, (B) is an AA sectional view. It is a front view which shows the switch for a check. It is the schematic of 2nd embodiment. It is a figure which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Junction box 14 Printed circuit board 16 Fuse accommodating part 17 ECU abnormality check part 21 CAN communication line 30 Branch circuit 40 Check switch 50 Trim 50a Maintenance opening 61 Instrument panel harness 62 Floor harness 63 Encoper harness 70 ECU

Claims (7)

An in-vehicle junction box containing an internal circuit for branch connection in a case,
As the internal circuit, a printed circuit board provided with a circuit for branching connection with a plurality of electronic control units serving as CAN communication nodes via a CAN communication line is accommodated.
An in-vehicle junction box characterized in that a check switch is provided in each branch circuit of the printed circuit board for switching connection / disconnection of a circuit when checking the abnormality of the connected electronic control unit.   The in-vehicle junction box according to claim 1, wherein the check switch is provided so as to be exposed on the outer surface of the case, and can be connected and disconnected from the outside by connecting and disconnecting the branch circuit.   The check switch is provided in a filter circuit in which a coil and a resistor formed in each branch circuit are connected in parallel, and an electrical component that connects the coil and the resistor in parallel is connected and disconnected from the outside. The in-vehicle junction box according to claim 1 or 2, wherein the in-vehicle junction box is freely cut.   The in-vehicle junction box according to any one of claims 1 to 3, wherein an ECU abnormality check portion in which all of the check switches are centrally arranged at one place is provided on the outer surface of the case.   The in-vehicle junction box according to claim 4, wherein the ECU abnormality check part is arranged adjacent to a fuse housing part provided on an outer surface of the case so that switching can be performed through a maintenance opening for fuse replacement. An in-vehicle junction box containing an internal circuit for branch connection in a case,
As the internal circuit, a printed circuit board provided with a circuit for branching connection with a plurality of electronic control units serving as CAN communication nodes via a CAN communication line, and a bus bar are housed.
A power branch circuit that individually supplies power to the plurality of electronic control units is provided on the printed circuit board or the bus bar, and a fuse present on the power branch circuit is used as a check switch when checking the abnormality of the electronic control unit. A junction box for in-vehicle use, characterized in that it is configured to switch between connection / disconnection and circuit connection / disconnection.   The CAN communication line is concentrated in an electric wire group of an instrument panel harness, an engine room harness, a floor harness, a door harness, and / or a roof harness connected to the internal circuit and wired in the vehicle. The in-vehicle junction box according to any one of claims 6 to 6.

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