TRUNK LINE OF WIRE HARNESS AND WIRE HARNESS

A trunk line of a wire harness includes a flexible printed circuit having a linear shape, and a plurality of connectors, one or more of the plurality of connectors being installed at each of a first side end portion and a second side end portion of the flexible printed circuit. Each of the plurality of connectors has a structure of being engaged with an external connector attached to an external electric wire.

TECHNICAL FIELD

The present disclosure relates to a trunk line of a wire harness and a wire harness.

BACKGROUND

Hitherto, there has been provided a wire harness installed within a vehicle to supply electric power or transmit a communication signal. JP2002-203431 A discloses a technique relating to a flat harness obtained by combining a flexible flat cable (FFC) and a flexible printed circuit (FPC) with each other.

SUMMARY OF THE INVENTION

The flat harness disclosed in JP2002-203431 A is obtained by combining the two types of wiring lines including the FFC and the FPC, and thus can be used separately for a high-current circuit and a low-current circuit. However, it is difficult to increase the size due to its structure, and expandability is low because the FFC and the FPC are integrated with each other.

It is an object of the disclosure to provide a trunk line of a wire harness and a wire harness that can be increased in size and improve expandability.

A trunk line of a wire harness according to an aspect of the present disclosure includes a flexible printed circuit having a linear shape, and a plurality of connectors, one or more of the plurality of connectors being installed at each of both side end portions of the flexible printed circuit, wherein each of the plurality of connectors has a structure of being engaged with an external connector attached to a branch line configured by an external electric wire.

A wire harness according to another aspect of the present disclosure includes a trunk line, and a plurality of branch lines being electrically connected to the trunk line, wherein the trunk line is the above-mentioned trunk line of the wire harness, and each of the plurality of branch lines is configured by the electric wire including one end portion to which the external connector to be engaged with the connector of the trunk line is attached.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the drawings, a trunk line of a wire harness and a wire harness according to each embodiment is described in detail. Note that the dimensional ratios in the drawings are exaggerated for explanatory purposes, and may differ from the actual ratios.

First Embodiment

FIG.1is a perspective view schematically illustrating an arrangement example of a wire harness1according to a first embodiment.FIG.2is a plan view schematically illustrating a configuration example of the wire harness1. For example, the wire harness1is a wiring line member that is routed within a vehicle, such as an automobile, to electrically connect a plurality of on-board devices to each other.

In the present embodiment, as one example, the wire harness1is attached to a cross-car beam111installed inside an instrument panel100of an automobile. The instrument panel100is an interior panel that is arranged at a front of a vehicle cabin and extends along a width direction of a vehicle to face a driver's seat and a passenger's seat. Note that, inFIG.1, the instrument panel100is indicated by the two-dot chain line. The cross-car beam111is a reinforcement member that is configured by a metal hollow pipe and is installed along a width direction of a vehicle. The flanges112are respectively joined to both ends of the cross-car beam111. One of the flanges112is fastened to a left front pillar of an automobile by a bolt, and the other of the flanges112is fastened to a right front pillar by a bolt. Note that, inFIG.1, the front pillars are omitted in illustration.

The wire harness1includes a trunk line10and a plurality of branch lines such as a first branch line13.

FIG.3is a perspective view schematically illustrating a configuration example of the trunk line10. The trunk line10includes an FPC11and a plurality of connectors12. Herein, FPC is an abbreviation of Flexible Printed Circuit.

The FPC11is a thin printed circuit excellent in flexibility. The FPC11includes a base film11f, a pattern layer11g, and a cover lay11h. The base film11fis a base material that is excellent in flexibility and defines a shape of the entire FPC11. For example, the base film11fis formed of a polyimide resin excellent in heat resistance. The pattern layer11gis laminated on a part of at least one main surface of the base film11f, and configures a plurality of conductive circuits. For example, the pattern layer11gis formed of a copper foil. The cover lay11his a protective layer that is laminated on the entire surface of the base film11f, that is, the base film11for the pattern layer11gvia an adhesive, which is omitted in illustration, and protects the pattern layer11gand the like.

Further, the FPC11, as a whole, has a linear shape that defines a length L, a width W, and a planar shape. Herein, the length L corresponds to a length of the FPC11in a longitudinal direction. The FPC11includes two side end portions, specifically, a first side end portion11aand a second side end portion11b, each of which extends along the longitudinal direction. The second side end portion11bis positioned on a side opposite to the first side end portion11ain the width direction. The length L falls within a range from 500 mm to 1,500 mm. The width W falls within a range from 40 mm to 100 mm.

One or more of the plurality of connectors12are installed at each of the first side end portion11aand the second side end portion11bof the FPC11. As one example, the trunk line10includes twelve connectors12. A first connector12a, a second connector12b, a third connector12c, and a fourth connector12dare installed at an interval therebetween on the first side end portion11a. Meanwhile, a fifth connector12e, a sixth connector12f, a seventh connector12g, an eighth connector12h, a ninth connector12i, a tenth connector12j, an eleventh connector12k, and a twelfth connector12mare installed at an interval therebetween on the second side end portion11b. Each of the connectors12has a structure of being engaged with any one of external connectors respectively attached to the plurality of branch lines. Note that specifications, such as the number of poles, of each of the connectors12or arrangement of each of the connectors12in the FPC11may be changed as appropriate in accordance with an attachment position of the wire harness1in a vehicle or the like.

Further, each of the connectors12is electrically connected to the pattern layer11gof the FPC11. Each of the plurality of conductive circuits configured by the pattern layer11gmay function as any one of a signal circuit, a signal GND circuit, a power-dedicated earth circuit, and the like. The signal circuit transmits a communication signal between on-board devices. The signal GND circuit electrically connects on-board devices along with the signal circuit, and aligns a reference potential for a circuit operation between the on-board devices. The power-dedicated earth circuit grounds a power source system of an on-board device.

Each of the plurality of branch lines is a type of an electric wire including one end connected to any one of the plurality of connectors12provided to the trunk line10and the other end connected to each electronic device or the like. In the present embodiment, as one example, there are nine branch lines including the first branch line13, a second branch line14, a third branch line15, a fourth branch line16, a fifth branch line17, a sixth branch line18, a seventh branch line19, an eighth branch line20, and a ninth branch line21.

Each of the branch lines includes an external connector that is engaged with any one of the connectors12of the trunk line10, a branch end portion that is connected to each electronic device or the like, and an electric wire that connects the external connector and the branch end portion to each other. The electric wire in the present embodiment is a linear and conductive member formed of metal, and is not an FPC. Further, the branch end portion in the present embodiment may be selected in accordance with a type and the number of electric wires, and may be a joint connector such as a multi-core connector or a crimped terminal. Further, the branch end portion in the present embodiment may be a junction block, or may be a relay block or the like.

For example, the first branch line13includes a first electric wire13a, a first external connector13b, and a first branch end portion13c. The plurality of first electric wires13aare provided in accordance with the two first branch end portion13having different shapes from each other. Those first electric wires13amay be any one of a power wire, a signal wire, a power-dedicated earth wire, and the like. Note that the plurality of first electric wires13amay be protected by an exterior protection member configured by a vinyl tube, an adhesive tape, or the like. Alternatively, the plurality of first electric wires13amay be bundled by a cable tie, which is omitted in illustration. The first external connector13bhas a structure of being engaged with the first connector12aof the trunk line10.

Meanwhile, for example, similarly to the configuration of the first branch line13, the eighth branch line20that is connected to the trunk line10via the tenth connector12jprovided to the second side end portion11bmay also include an eighth electric wire20a, an eighth external connector20b, and an eighth branch portion20c. The eighth external connector20bhas a structure of being engaged with the tenth connector12jof the trunk line10.

Further, for example, the configuration of each of the branch lines is not limited to the example of the first branch line13, and may be, for example, a configuration similar to the second branch line14, the fifth branch line17, or the seventh branch line19.

The second branch line14includes a second electric wire14a, a second external connector14b, and a second branch end portion14c. Each of the two second branch end portions14cmay include a simple configuration as compared to the first branch end portion13c. The second external connector14bhas a structure of being engaged with the second connector12bof the trunk line10. However, the engagement structure between the second connector12band the second external connector14bmay be smaller in size than the engagement structure between the first connector12aand the first external connector13b.

Meanwhile, for example, similarly to the configuration of the second branch line14, the third branch line15that is connected to the trunk line10via the third connector12cmay also include a third electric wire15a, a third external connector15b, and a third branch end portion15c. The third external connector15bhas a structure of being engaged with the third connector12cof the trunk line10. Further, for example, similarly to the configuration of the second branch line14, the fourth branch line16may also include a fourth electric wire16a, a fourth external connector16bengaged with the fourth connector12dof the trunk line10, and a fourth branch end portion16c. Further, similarly to the configuration of the second branch line14, the sixth branch line18may also include a sixth electric wire18a, a sixth external connector18bengaged with the seventh connector12gof the trunk line10, and a sixth branch end portion18c.

The fifth branch line17includes a fifth electric wire17a, a fifth external connector17b, and a fifth branch end portion17c. In the fifth branch line17, the number of fifth branch end portions17cis greater than the number of first branch end portions13cin the first branch line13. Further, in the fifth branch line17, the number of fifth external connectors17bis greater than the number of first external connectors13bin the first branch line13. In the example of the fifth branch line17, the two fifth external connectors17bare present. In this case, one of the fifth external connectors17bhas a structure of being engaged with the fifth connector12e, and the other of the fifth external connectors17bhas a structure of being engaged with the sixth connector12fadjacent to the fifth connector12e.

Meanwhile, for example, similarly to the configuration of the fifth branch line17, the ninth branch line21that is connected to the trunk line10via the eleventh connector12kand the twelfth connector12mmay also include a ninth electric wire21a, two ninth external connectors21b, and three ninth branch end portions21c. In this case, one of the ninth external connectors21bhas a structure of being engaged with the eleventh connector12k, and the other of the ninth external connectors21bhas a structure of being engaged with the twelfth connector12madjacent to the eleventh connector12k.

The seventh branch line19includes a seventh electric wire19a, a seventh external connector19b, and a seventh branch end portion19c. In the seventh branch line19, the number of seventh electric wires19ais greater than the number of first electric wires13ain the first branch line13. Further, in the seventh branch line19, the number of seventh external connectors19bis greater than the number of first external connectors13bin the first branch line13. In the example of the seventh branch line19, the two seventh external connectors19bare present. In this case, one of the seventh external connectors19bhas a structure of being engaged with the eighth connector12h, and the other of the seventh external connectors19bhas a structure of being engaged with the ninth connector12iadjacent to the eighth connector12h.

Herein, the first branch line13, the second branch line14, the third branch line15, or the fourth branch line16, which is routed from the first side end portion11aof the FPC11to a driver's seat side or a passenger's seat side, may be connected to electric equipment, such as a meter panel and an air-conditioning device, that is attached to the instrument panel100. Meanwhile, the fifth branch line17, the sixth branch line18, the seventh branch line19, the eighth branch line20, or the ninth branch line21, which is routed from the second side end portion11bof the FPC11to an engine room side may be connected to a main battery, various control boxes, or the like.

Next, effects of the trunk line10of the wire harness1and the wire harness1including the trunk line10are described.

The trunk line10of the wire harness1according to the present embodiment includes the FPC11having a linear shape and the plurality of connectors12, one or more of the plurality of connectors12being installed at each of the first side end portion11aand the second side end portion11bthat are both the side end portions of the FPC11. Each of the plurality of connectors12has a structure of being engaged with the external connector attached to the external electric wire.

Herein, the external electric wire corresponds to the above-mentioned branch line, such as the first branch line13and the like, in the wire harness1. The external connector corresponds to the first external connector13band the like described above, which are attached to the respective branch line.

Further, the wire harness1according to the present embodiment includes the trunk line10, the plurality of branch lines, such as the first branch line13and the like, which are electrically connected to the trunk line10. Each of the plurality of branch lines is configured by the electric wire including one end portion to which the external connector to be engaged with the connector12of the trunk line10is attached.

First, in the present embodiment, the trunk line10of the wire harness1is configured by the FPC11instead of an electric wire. Therefore, the trunk line10configured by the FPC11is reduced in weight as compared to a trunk line obtained by bundling various types of general electric wires. Herein, as described above, when the wire harness1is installed within a vehicle, it is assumed that the length L of the trunk line10is approximately 1,000 mm. Herein, when the trunk line having such a length is configured entirely by electric wires, a weight of the trunk line itself, consequently, that of a wire harness as a whole is significantly increased. In contrast, according to the trunk line10or the wire harness1, the trunk line10or the wire harness1as a whole is reduced in weight to a higher extent as the length L is set longer, and hence a size increase of the wire harness1can easily be suppressed while suppressing a weight increase.

For example, as described above, it is assumed that the wire harness1is attached to the inside of the instrument panel100. In general, a large-size wire harness, which is attached within the instrument panel100as described above, includes a large number of branch lines corresponding to various devices such as a meter, an air-conditioning device, and an audio device, and is heavier than wire harnesses attached to other parts of a vehicle. Further, in such a large-size wire harness, some branch lines may include connectors such as a joint connectors, which are not actually used. In contrast, the wire harness1according to the present embodiment enables connection of a suitable branch line including a required connector only, and hence it is possible to eliminate a branch line including preparatory connectors, which are not actually used. Therefore, according to the wire harness1according to the present embodiment, a weight loss by approximately 30% can be achieved as compared to a general wire harness including a trunk line configured by bundling various electric wires.

Further, in general, in a large-size wire harness including a trunk line configured by bundling various electric wires, due to its structure, it may be difficult to adopt, as a branch line, a thin electric wire having a permissive current value of approximately a few milliamperes. In contrast, in the present embodiment, the trunk line10has a small thickness as a whole, and is configured by the FPC11including the fine pattern layer11g, and hence it is easy to adopt a structure of connecting a branch line formed of an electric wire defined with the above-mentioned current range.

Further, in general, a wire harness including a trunk line configured by bundling various electric wires is manufactured manually by a worker. In view of this, the FPC11can be manufactured through automation, and hence the number of steps of manufacturing the trunk line10, consequently, the number of steps of manufacturing the wire harness1can also be reduced by configuring the trunk line10by the FPC11.

Further, in the present embodiment, an external electric wire, that is, a branch line is connected to the trunk line10via the connector12, and hence is attached and removed freely with respect to the trunk line10. Therefore, in the final step of manufacturing the wire harness1, a worker is only required to connect a plurality of branch lines that are prepared in advance to the trunk line10. For example, a worker can assemble the wire harness1as a whole by first attaching, to the cross-car beam111, the trunk line10before connection to branch lines, and then connecting the respective branch lines to the trunk line10. In other words, this may contribute to reduction of the number of steps of designing the wire harness1or facilitation of a manufacturing work of a vehicle adopting the wire harness1. Further, according to the trunk line10and the wire harness1, a branch line can be replaced with respect to one trunk line10. Therefore, when one branch line is damaged, only the damaged branch line can easily be replaced. Meanwhile, the trunk line10is commonly shared, and only a desired branch line is changed as appropriate. With this, various wire harnesses1having different types or lengths of respective branch lines being adopted can easily be configured. Further, it is possible to provide a so-called add-on expansion function that allows a new function, which is not originally set to the wire harness1at the time of assembling to a vehicle, to be added after the assembly. Note that the trunk line10configured by the FPC11may be attached to the cross-car beam111via a protector for covering and protecting the entire trunk line10.

Further, a branch line can freely be attached and removed with respect to the trunk line10, and hence the following advantages are provided. Firstly, according to the wire harness1, the trunk line10and the plurality of branch lines may be managed under respective original item numbers. For example, as a comparative example, there is assumed a case where a plurality of general wire harnesses that are different from each other only in a length of a certain branch line are provided. In this case, the plurality of wire harnesses1are respectively denoted with different item numbers, and are managed. In contrast, according to the wire harness1, the branch lines having different lengths are respectively denoted with item numbers, and the trunk line10that is commonly shared is denoted with one item number and is managed. Therefore, it is possible to easily increase the variations of branch line changes and contribute to the simplification of labor management associated with changes in the configuration of the wire harness1. Secondly, in general, it is also difficult to transport a large-size wire harness including a trunk line configured by bundling various electric wires, due to its weight. In contrast, according to the wire harness1, the trunk line10and the branch line can be transported separately, and hence there are advantages such as shortening the manufacturing days of the wire harness1itself or a vehicle using the wire harness1, and reducing the limitations on manufacturing locations. Thirdly, according to the wire harness1, the branch line can be manufactured independently from the trunk line10, and hence nay be manufactured by an automated machine rather than manual work by a worker. In other words, according to the wire harness1, both the trunk line10configured by the FPC11and the branch line configured by the electric wire, in other words, the wire harness1as a whole can be manufactured by an automated machine, which is advantageous for reducing costs.

Further, in the present embodiment, the FPC11has a linear shape, and hence, the trunk line10and the wire harness1are easily adopted to various attachment parts within a vehicle. Note that, even when the FPC11has an elongated shape having the length L of approximately 1,000 mm, the FPC11having a linear shape can further facilitate manufacturing of the FPC11in an FPC manufacturing device.

Further, in the present embodiment, one or more of the plurality of connectors12are installed at each of the first side end portion11aand the second side end portion11b, and hence the trunk line10can connect the respective branch lines to each other from the opposite sides. Therefore, as described above, when the wire harness1is installed within a vehicle, the trunk line10enables an increase in the number of set branch lines to be connected and an increase in variation of the configurations of the wire harness1.

Further, in the present embodiment, each of the plurality of connectors12has a structure of being engaged with an external connector attached to an external electric wire. In other words, an external electric wire, that is, the branch line itself has a structure similar to that of a branch line of a general wire harness, and hence the wire harness1can easily be used in place of a general wire harness configured entirely by electric wires.

As described above, according to the present embodiment, it is possible to provide the trunk line10of the wire harness1and the wire harness1that can be increased in size and improve expandability.

Further, in the trunk line10, the length L of the FPC11may fall within a range from 500 mm to 1,500 mm. The width W of the FPC11may fall within a range from 40 mm to 100 mm.

The trunk line10is suitable particularly in a case where the wire harness1is installed within a vehicle as exemplified above. Further, when the length L and the width W of the FPC11are set within the above-mentioned ranges, the wire harness1including the trunk line10can be used more widely in place of a general wire harness configured entirely by electric wires.

Second Embodiment

In the wire harness1according to the first embodiment, only the trunk line10configured by the FPC11is adopted as a trunk line. In view of this, in a wire harness2according to a second embodiment, an auxiliary wiring line22capable of functioning as a part of the trunk line is further adopted in addition to the FPC11.

FIG.4is a plan view schematically illustrating a configuration example of the wire harness2.FIG.4is illustrated so as to correspond toFIG.2illustrating the configuration example of the wire harness1according to the first embodiment. Hereinafter, among the constituent elements of the wire harness2, the same constituent elements as those of the wire harness1are denoted with the same reference symbols, and description therefor is omitted.

The wire harness2includes the auxiliary wiring line22configured by an electric wire. In the wire harness2, a position at which the auxiliary wiring line22is arranged is not particularly limited, and is arranged between the fifth branch line17and the sixth branch line18in the present embodiment, as one example. The auxiliary wiring line22includes one auxiliary electric wire22a, a first wiring line terminal22battached to one end of the auxiliary electric wire22a, and a second wiring line terminal22cattached to the other end of the auxiliary electric wire22a. For example, the auxiliary wiring line22may be bundled together with another adjacent branch line, such as the sixth branch line18. Herein, a part of the auxiliary wiring line22is arranged along at least a part of the trunk line10in the longitudinal direction. In the example illustrated inFIG.4, in a parallel section P, the trunk line10and a part of the auxiliary wiring line22are arranged in parallel to each other. In other words, as well as the trunk line10, a part of the auxiliary wiring line22in the parallel section P may be regarded as a part of the trunk line in the wire harness2.

In this manner, the wire harness2may include the auxiliary wiring line22configured by an electric wire. Further, a part of the auxiliary wiring line22may be arranged along at least a part of the trunk line10in the longitudinal direction.

Herein, the trunk line10is configured by the FPC11, but, when attempting to conduct a relatively large current from one branch line to another branch line via the trunk line10, it is conceivable that conduction might be practically difficult in a conductor circuit included in the pattern layer11gof the FPC11. In view of this, according to the wire harness2, when a need arises to pass such a large current through the trunk line, it can be addressed by routing the current through the auxiliary wiring line22configured by an electric wire, instead of passing it through the trunk line10configured by the FPC11. In this state, as the auxiliary electric wire22a, an auxiliary electric wire having a suitable wire width for conducting a desired current is selected in advance.

Third Embodiment

In the wire harness2according to the second embodiment, a part of the auxiliary wiring line22that can further function as a trunk line is arranged in parallel to the trunk line10configured by the FPC11. In view of this, in a wire harness3according to a third embodiment, an auxiliary trunk line40being a trunk line connected to an FPC31in series is adopted.

FIG.5is a plan view schematically illustrating a configuration example of the wire harness3.FIG.5is illustrated so as to correspond toFIG.2illustrating the configuration example of the wire harness1according to the first embodiment. Hereinafter, among the constituent elements of the wire harness3, the same constituent elements as those of the wire harness1are denoted with the same reference symbols, and description therefor is omitted.

First, the wire harness3includes a trunk line30in place of the trunk line10of the wire harness1. The trunk line30includes the FPC31, a second connector32b, a third connector32c, a fourth connector32d, a seventh connector32g, an eighth connector32h, a ninth connector32i, a tenth connector32j, an eleventh connector32k, and a twelfth connector32m. The FPC31has substantially the same structure as the FPC11of the trunk line10, but the region of the trunk line10where the first branch line13and the fifth branch line17are connected to each other is replaced with the auxiliary trunk line40in the present embodiment. Note that the above-mentioned connectors of the trunk line30respectively correspond to the connectors of the trunk line10, which are denoted with the same names.

Further, similarly to the FPC11, the FPC31includes a first side end portion31aand a second side end portion31b, and a distal end portion31calong the width W vertical to both the first side end portion31aand the second side end portion31bis defined in the present embodiment. At the distal end portion31c, an auxiliary connector32nis installed. Similarly to the second connector32band the like, the auxiliary connector32nis also electrically connected to the pattern layer included in the FPC31, which is omitted in illustration.

Further, the wire harness3includes the auxiliary trunk line40configured by an electric wire. An auxiliary external connector40aconnected to the auxiliary connector32nis attached to one end of the auxiliary trunk line40. In other words, the auxiliary connector32nof the FPC31has a structure of being engaged with the auxiliary external connector40a. Meanwhile, at the other end of the auxiliary trunk line40, an end connector40bthat can be connected to other electric devices or the like may be attached.

At least one branch line branches from the auxiliary trunk line40. In the example illustrated inFIG.4, a tenth branch line41in place of the first branch line13of the trunk line10and an eleventh branch line42in place of the fifth branch line17of the trunk line10branch from the auxiliary trunk line40. The tenth branch line41includes a tenth electric wire41aand a tenth branch end portion41b. The eleventh branch line42includes an eleventh electric wire42aand an eleventh branch end portion42b.

In this manner, the wire harness3may include the auxiliary trunk line40configured by an electric wire. The trunk line30may include the auxiliary connector32ninstalled at the one distal end portion31cof the FPC31. The auxiliary connector32nmay have a structure of being engaged with the auxiliary external connector40aattached to the auxiliary trunk line40.

In the wire harness3, not all the trunk lines are configured by FPCs, but a trunk line in which an FPC part corresponding to the FPC31and an electric wire part corresponding to the auxiliary trunk line40are continuous with each other in series is provided. For example, the auxiliary trunk line40described above may be used as a circuit for an air bag or an antenna. In this state, the auxiliary trunk line40may include an important circuit such as a power line or a conditional circuit. Therefore, according to the wire harness3, expandability can further be improved.

Note that, in the description given above, a case where the wire harness1is attached to the inside of the instrument panel100of the automobile is given as an example. However, the attachment position of the wire harness1is not limited thereto, and may be, for example, under a floor or inside a roof of an automobile.