TECHNICAL FIELD

The present invention relates to a vehicular circuit body routed in a vehicle.

BACKGROUND ART

In a vehicle, for example, source power is required to be appropriately supplied to a large number of various electric components from an alternator (generator) or a battery which is a main power source. A system used to supply such source power is also required to have a function of switching between ON and OFF of the supply of power as necessary, or a function of cutting off a current for each system in a case where an excessive current flows through an electric component.

In a general vehicle, a wire harness which is an aggregate of a plurality of electric wires is routed on the vehicle, and a main power source is connected to electric components at each location via the wire harness so that power is supplied thereto. Generally, a junction block is used to distribute source power to a plurality of systems, a relay box is used to control ON and OFF of the supply of power for each system, or a fuse box is used to protect each electric wire or a load of the wire harness.

The vehicle is provided with a plurality of control units for controlling the electric components, and the control units and the electric components are communicably connected to each other via the wire harness.

For example, a wire harness disclosed in Patent Document JP-A-2005-78962 includes a network transmission path and a circuit for providing power, GND and other signals. The wire harness includes a wire harness trunk line, a sub-wire harness, an optional sub-wire harness, and a network hub device.

SUMMARY

In recent years, vehicle systems including such a power source system or communication system have become advanced due to an increase in the number of mounted electric components, complexity of control, or the like. An automatic driving technology is rapidly evolving, and safety requirements for various functions are also increasing in order to cope with this automatic driving.

Along with this, a structure of a wire harness routed on a vehicle body tends to be complicated. Therefore, for example, as in Patent Document JP-A-2005-78962, the wire harness having a complex shape as a whole is formed by combining the wire harness trunk line, the sub-wire harness, and the optional sub-wire harness, and thus connection to various electric components disposed at various locations on a vehicle body can be performed.

Since a diameter of each electric wire forming the wire harness or the number of electric wires increases due to an increase in the number of electric components mounted on a vehicle, there is a tendency that a size of the entire wire harness increases or a weight thereof increases. The types and the number of components of wire harness to be manufactured increase due to a difference between vehicle models mounted with a wire harness or increases in types of optional electric components mounted on a vehicle, and thus it is difficult to standardize components forming the wire harness, and component cost or manufacturing cost increases.

In a work process of manufacturing a wire harness, in order to finish the wire harness in a predetermined routing shape, a bundle of a plurality of electric wires forming the wire harness is pulled around over a long distance along a path which is designated in advance, and thus a lot of work time is required. Since almost all of electric wires are collected at a trunk line portion of the wire harness, the number of bundled electric wires increases, and thus a weight thereof increases.

For example, in a case where a new electric component which is not expected at initial design is mounted on a vehicle, a new electric wire is required to be added to a wire harness in order to secure a path along which a special signal is transmitted between the electric component and another electric component or to supply source power thereto. However, a wire harness has a complex structure or shape, and it is very difficult to add other electric wires to the existing wire harness in the future. Therefore, a new wire harness having differing type or component number is required to be designed so as to be manufactured as a separate product.

The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a vehicular circuit body in which a structure for electrical connection between various electric components and a power source on a vehicle and between the electric components, particularly, a configuration of a trunk line portion is simplified and a new electric wire can be easily added.

In order to achieve the above-described object, a vehicular circuit body according to the present invention is characterized in terms of the following (1) to (5).

(1) A vehicular circuit body, comprising:

a trunk line that includes a power source line having a predetermined current capacity and a communication line having a predetermined communication capacity, and that is routed in a vehicle body; and

a plurality of control boxes that are disposed in a distribution manner along the trunk line,

wherein the trunk line includes a first trunk line portion extending in a front-and-rear direction of the vehicle body and a second trunk line portion extending in a leftward-and-rightward direction of the vehicle body, and

wherein the plurality of control boxes include a branch control box that connects the first trunk line portion and the second trunk line portion, and distributes power from one of the first trunk line portion and the second trunk line portion to the other one.

With this configuration, the trunk line, routed in the vehicle with a predetermined current capacity and a predetermined communication capacity, can be branched to a plurality of trunk lines from a branch control box. This makes it possible to allocate the control boxes that are disposed along the trunk line in a distribution manner to a variety of portions in the vehicle.

Therefore, it is possible to supply power to or easily transmit and receive communication data (signal) to and from accessories disposed at the respective locations of the vehicle via the branch lines connected to the control boxes, and thus it is also possible to shorten the branch lines.

(2) The vehicular circuit body according to the above (1),

wherein the first trunk line portion is disposed along a vehicle interior floor of a vehicle, and

wherein the second trunk line portion is disposed in an instrument panel of the vehicle.

With this configuration, power distribution from any of the plurality of control boxes to the accessories disposed in the vehicle interior and the vicinity of the vehicle interior can be easily achieved. In addition, because the first trunk line portion extends in a front-and-rear direction of the vehicle body, it is possible to supply power to the trunk line from these control boxes even if the control boxes are disposed at a front and rear portions of the vehicle in a distributed manner.

(3) The vehicular circuit body according to the above (1) or (2), further comprising:

a branch line with one end connected to any one of the plurality of control boxes and the other end directly or indirectly connected to an accessory.

With this configuration, accessories can be connected to the trunk line via the plurality of control boxes disposed along the trunk line in a distributed manner.

In addition, the vehicular circuit body is separately formed of the trunk line which is used in common to a plurality of vehicle models, grades, or options, and the branch line which is changed depending on a plurality of vehicle models, grades, or optional accessories. Therefore, even if the number of vehicle models, grades, or optional accessories increases, only the branch lines having different wirings need to be prepared depending on a plurality of vehicle models, grades, or optional accessories, and thus it is possible to facilitate manufacturing of the vehicular circuit body and to reduce cost.

(4) The vehicular circuit body according to any one of the above (1) to (3),

wherein the trunk line is formed of a routing material having at least one kind of conductor among a flat conductor, a round bar conductor, and a stranded wire.

With this configuration, the power source line of the trunk line requires a large sectional area in order to secure a predetermined current capacity. Therefore, in a case where the power source line is formed of a routing material having a flat conductor whose sectional shape is a flat strip shape, bending in a thickness direction is facilitated, and thus work for routing the power source line along a predetermined routing path is facilitated. In a case where the power source line is formed of a routing material having a highly versatile round bar conductor or stranded wire, the power source line can be easily manufactured and be freely bent in all directions. Therefore, the routing property improves.

(5) The vehicular circuit body according to any one of the above (1) to (4),

wherein the trunk line further includes an earth line having a predetermined current capacity.

With this configuration, the earth line extends in parallel to the power source line in the trunk line, and thus it is possible to prevent sneaking of power source noise into the communication line.

The power source line and the earth line formed of a routing material having a flat conductor are disposed in a stacking manner such that a surface area of surfaces facing each other is increased and a gap therebetween is reduced, so that it is possible to further improve the noise resistance performance.

It is possible to provide a vehicular circuit body in which a configuration of a trunk line portion is simplified and a new electric wire can be easily added.

As mentioned above, the present invention has been described briefly. Details of the present invention will become more apparent by reading through modes for carrying out the invention (hereinafter, referred to as “embodiments”) described below with reference to the accompanying drawings.

