JP7840697B2 - Branch box, branch structure, and construction method for branch structure - Google Patents

Description

This invention relates to a branching box, etc., for an automobile, which branches off from a main cable connected to the power supply to various electrical devices.

In electric vehicles such as BEVs (Battery Electric Vehicles) and HEVs (Hybrid Electric Vehicles), multiple high-voltage-driven units are installed. Traditionally, a unit called a PCU (Power Control Unit), which includes an inverter, supplies power to each unit it wants to drive, thereby operating the electrical equipment.

However, depending on the PCU output and the number of units installed, a junction box, such as a power distribution junction box, may be required for relaying rather than direct connection. Therefore, multiple power distribution junction boxes are necessary to connect multiple units.

One such structure, for example, is disclosed in Patent Document 1, where a first power line is connected to a power supply mounted on a vehicle, the first power line is connected to a first power distributor, the first power distributor is further connected to a second power distributor via a first power trunk line, the second power distributor is connected to a third power distributor via a second power trunk line, and the third power distributor is connected to a fourth power distributor via a third power trunk line.

Japanese Patent Publication No. 2019-137394

However, as described in Patent Document 1, the method of connecting power distributors with a main power line requires a main circuit to connect each power distributor (distribution junction box). This results in an increased number of components.

Furthermore, when adding equipment due to minor vehicle changes, it may be necessary to divide the existing main circuit and install new power distribution junction boxes and wire harnesses. However, due to layout constraints, power distribution junction boxes cannot always be placed in the shortest possible location between units, resulting in longer connecting wires.

This invention has been made in view of the above problems, and aims to provide a branch box for a main power supply circuit in an automobile that makes power distribution easier.

To achieve the aforementioned objective, the first invention is a branch box for a power main circuit of an automobile, comprising a housing, a holder disposed inside the housing, a busbar held by the holder, and a connector disposed in the housing, wherein the busbar has a main cable connection portion that can be connected to a main cable and a connector connection portion that can be connected to the connector , the holder has a main cable mounting portion on which a main cable can be placed, and a busbar holding portion that stands above the main cable mounting portion and is sandwiched between a pair of busbars to ensure an insulating distance between the busbars, and the busbar is characterized in that it is substantially T-shaped or substantially H-shaped .

A fuse may be connected between the connector connection portion and the connector.

The holder may be made of resin and have a substantially inverted T-shape or substantially cross-shaped form when viewed from the front .

The aforementioned enclosure may be made of metal.

The housing may have a cable penetration portion through which a main cable can pass, and a projection may be formed around at least a portion of the cable penetration portion, with a braided wire being able to be fixed to the projection.

According to the first invention, since the busbar can be directly connected to the main cable inside the enclosure, there is no need to separate the main cable into multiple branches, minimizing the increase in the number of components. Furthermore, since connectors are attached to the busbar, connection to branched wire harnesses and the like is also easy.

Furthermore, if the holder has a main cable mounting section on which the main cable can be placed, the main cable can be held more securely, and displacement can be suppressed. Also, if the holder has a busbar holding section that is sandwiched between a pair of busbars to ensure the insulation distance between the busbars, short circuits between the busbars can be reliably suppressed.

Furthermore, by placing a fuse between the connector connection and the connector itself, the circuit can be protected from overcurrent.

Furthermore, if the holder is made of resin, it will be lightweight and, for example, provide insulation between busbars.

Furthermore, if the enclosure is made of metal, noise shielding performance can be ensured for the branching box.

Furthermore, by forming protrusions around at least a portion of the cable penetration area formed in the housing, and by allowing the braided wire to be fixed to these protrusions, noise shielding performance by the braided wire can be ensured even for the main cable passing through the housing.

The second invention is a branching structure using a branching box according to the first invention, characterized in that at least one pair of trunk cables pass through the housing, a portion of the covering of each trunk cable is removed inside the housing to expose the internal conductor, and the trunk cable connection portion of the busbar is joined thereto.

The conductor of the main cable and the main cable connection portion of the busbar may be joined by welding.

The conductor of the main cable and the main cable connection portion of the busbar may be joined by crimping.

The holder has a trunk cable mounting section on which a trunk cable can be placed, and a busbar holding section that ensures an insulating distance between a pair of busbars. The pair of trunk cables may be placed on the trunk cable mounting section, the busbar holding section may be placed between the pair of trunk cables, and the busbar holding section may be sandwiched between the pair of busbars. The busbars may be sandwiched between the busbar holding section and the pair of trunk cables.

According to the second invention, within the housing, a portion of the sheathing of each trunk cable is removed, exposing the internal conductor. Since the trunk cable connection portion of the busbar and the trunk cable conductor are directly joined, there is no need to separate the trunk cables into multiple sections, minimizing the increase in the number of components. Furthermore, even with existing trunk cables, there is no need to cut them, providing greater flexibility in layout.

Furthermore, the conductors of the main cable and the main cable connection portion of the busbar may be joined by welding or crimping. In either case, the main cable conductors and the busbar can be connected with high reliability without the use of separate parts.

Furthermore, by positioning a pair of trunk cables on the trunk cable mounting section of the holder, the trunk cables can be securely held by the holder. Additionally, by positioning the busbar holding section between the pair of trunk cables so that it is sandwiched between the pair of busbars, the insulation distance between the busbars can be reliably ensured.

The third invention is a method for constructing a branch structure using a branch box according to the first invention, characterized in that a portion of the covering of at least one pair of trunk cables is removed to expose the internal conductors, the trunk cable connection portion of the busbar is joined to the conductors of each of the trunk cables, the holder is placed between the pair of busbars, the busbar holding portion and the pair of busbars are sandwiched between the pair of trunk cables, and the busbars and the holder are covered with the housing.

According to the third invention, a branching structure can be easily formed on an existing trunk cable.

According to the present invention, it is possible to provide a branch box for a main power supply circuit in an automobile that makes power distribution easier.

Exploded perspective view of branch box 1. (a) is a front view of the holder 5, and (b) is a side view of the bus bar 7. (a) is a perspective view of a partially assembled branch box 1, and (b) is a perspective view showing the branch structure 10. (a) is an axial cross-sectional view of the branch structure 10, and (b) is a cross-sectional view of the branch structure 10 perpendicular to the axial direction. Axial cross-sectional view of branch structure 10a. Exploded perspective view of branch box 1a. (a) is a front view of the holder 5a, and (b) is a side view of the busbar 7a. Axial cross-sectional view of branch structure 10b. This figure shows the branching structure 10c, where (a) is a perspective view showing the state before the braided wire 35 is attached, and (b) is a perspective view showing the state after the braided wire 35 is attached.

The embodiments of the present invention will be described below with reference to the drawings. Figure 1 is an exploded perspective view of the branch box 1. The branch box 1 is used for a power main circuit in an automobile.

The branch box 1 mainly consists of a housing 3, a holder 5, a pair of busbars 7, and connectors 9. The housing 3 is, for example, made of metal. The housing 3 is divided into two parts, which can be joined together and fixed in a single integrated state. Furthermore, the housing 3 has an external fixing part that allows it to be fixed to a vehicle body or the like, and it is also possible to connect an earth wire to the fixing part for grounding.

For each segment of the housing 3, a cable penetration section 25 and a connector fixing section 27 are provided on the opposing surfaces adjacent to the opening (the front and back surfaces in the diagram). The cable penetration section 25 is the part through which the main cable, described later, passes. The cable penetration section 25 is formed as a notch in each segment of the housing 3, and when the segments are joined together, the overall shape is approximately oval. The direction of the opposing surfaces where the cable penetration section 25 is formed is considered the axial direction of the branch box 1.

Similarly, a connector fixing portion 27 is formed in a notched shape above the cable penetration portion 25. When the divided parts are joined together, the overall shape corresponds to the connector 9 (roughly rectangular in the figure). The connector 9 is placed in the connector fixing portion 27 and secured, for example, with bolts. In other words, the connector 9 is placed in the housing 3. A general-purpose connector can be used as the connector 9.

A holder 5 is positioned inside the housing 3. Figure 2 is a front view of the holder 5. The holder 5 has a roughly inverted T-shape and includes a trunk cable mounting section 17 on which the trunk cable (described later) can be placed, and a busbar holding section 19 that stands above the trunk cable mounting section 17. The trunk cable mounting section 17 is formed to be roughly flat and is the area where the trunk cable is placed. The trunk cable mounting section 17 may be provided with a fixing structure (such as a band) capable of holding and securing the trunk cable.

The busbar holder 19 has a certain thickness and is positioned between the main cable mounting sections 17 (approximately in the center in the width direction). The busbar holder 19 is sandwiched between a pair of busbars 7, ensuring sufficient insulation distance between them. That is, the holder 5 is made of an insulating material, such as resin. The busbar holder 19 may be provided with a fixing structure (such as a screw) capable of holding and securing the busbars 7.

A pair of busbars 7 are positioned so as to sandwich the busbar holding portion 19 of the holder 5, and are held by the holder 5. Figure 2(b) is a side view of the busbar 7. The busbar 7 is roughly T-shaped, with connector connection portions 21 provided at both ends, and a trunk cable connection portion 23 is provided between the connector connection portions 21 so as to protrude downward. The connector connection portions 21 can be connected to the connector 9, and the trunk cable connection portion 23 can be connected to the trunk cable. The busbar 7 is, for example, a plate-shaped metal member.

Figure 3(a) is a perspective view showing the main cable 11 and busbar 7 fixed to the holder 5, and Figure 3(b) is a perspective view showing the branching structure 10 using the branching box 1 with the housing 3 closed. Furthermore, Figure 4(a) is an axial cross-sectional view of the branching structure 10, and Figure 4(b) is a cross-sectional view perpendicular to the axial direction of the branching structure 10.

The construction method for the branching structure 10 involves first arranging at least one pair of main cables 11 (two-pole wires, positive and negative). Each main cable 11 consists of a conductor 13 and a covering 15 that insulates the conductor 13. At the location where the branching structure 10 is to be installed, a portion of the covering 15 of the main cable 11 is removed to expose the internal conductor 13.

Next, the main cable connection portion 23 of the busbar 7 is joined to the conductor 13 of each main cable 11. The conductor 13 of the main cable 11 and the main cable connection portion 23 of the busbar 7 may be joined by, for example, welding or crimping. In the case of crimping, for example, a part of the main cable connection portion 23 may be bent to form the crimped portion. Through these steps, the main cable 11 and the busbar 7 are electrically connected.

Next, the holder 5 is positioned so that the busbar holding portion 19 is placed between the pair of busbars 7. That is, the pair of main cables 11 are placed on the main cable mounting portion 17 of the holder 5, the busbar holding portion 19 is placed between the pair of main cables 11, and the busbar holding portion 19 is sandwiched between the pair of busbars 7. If necessary, the main cables 11 are fixed to the main cable mounting portion 17, and the busbars 7 are fixed to the busbar holding portion 19. Furthermore, connectors 9 are connected to the connector connection portions 21 of each busbar 7. The connectors 9 are fixed by welding or bolts, etc. Note that the holder 5 may be positioned after the connectors 9 are fixed.

Finally, the branch structure 10 is constructed by butting together and fixing the divided parts of the housing 3 so as to cover the busbar 7 and holder 5, etc. That is, in the branch structure 10, at least one pair of main cables 11 pass through the housing 3. Also, inside the housing 3, a portion of the sheathing 15 of each main cable 11 is removed, exposing the internal conductor 13, and the main cable connection portion 23 of the busbar 7 is joined to it. Furthermore, a connector 9 is connected to the connector connection portion 21 of the busbar 7, and the connector 9 is fixed to the housing 3.

As explained above, according to this embodiment, a portion of the sheathing 15 of the main cable 11 is removed, and the busbar 7 is directly joined to the internal conductor 13. Therefore, there is no need to cut and connect the main cable 11 at both ends of the branch box 1. Furthermore, since the busbar 7 and the conductor 13 are joined by welding or crimping, contact reliability is high. For example, if one attempts to directly contact the terminals of a connector with a clip or the like with the main cable 11, which has a roughly circular cross-section, there is a risk of poor contact. However, by joining the plate-shaped busbar 7 to the conductor 13 by welding or crimping, the two can be reliably connected.

Furthermore, since the pair of trunk cables 11 are placed on the trunk cable mounting section 17 of the holder 5, displacement of the trunk cables 11 is suppressed. Also, a busbar holding section 19 of the holder 5 is provided between the pair of trunk cables 11, and the busbar 7 is fixed to the busbar holding section 19. Therefore, the busbar 7 and the trunk cables 11 are securely fixed to the holder 5, resulting in higher contact reliability.

Furthermore, since the busbar holding portion 19 is made of an insulator and has a thickness sufficient to maintain the insulating distance between the busbars 7, short circuits between the busbars 7 can be suppressed.

Furthermore, a connector connection portion 21 is formed on the busbar 7, and by joining the connector 9 to the busbar 7, the connector 9 can be integrated with the housing 3. Therefore, connection work with branch cables and the like that have general-purpose connectors is easy. In this case, since the connector 9 is arranged on both sides of the housing 3 in the direction in which the main cable 11 passes through, it is also possible to bundle the connected branch cable with the main cable 11. Note that the connector 9 may be on the top side of the housing 3, or it may be arranged on the side perpendicular to the main cable 11.

Next, a second embodiment will be described. Figure 5 is an axial cross-sectional view showing the branch structure 10a according to the second embodiment. In the following description, components that perform the same functions as those in the first embodiment are denoted by the same reference numerals as in Figures 1 to 4, and redundant explanations are omitted.

The branch structure 10a has substantially the same configuration as the branch structure 10, but differs in that it uses a fuse 29. At least, the fuse 29 is connected between the connector connection portion 21 of the busbar 7, which is connected to the positive terminal main cable 11, and the connector 9.

In the illustrated example, fuses 29 are positioned at both connector connection points 21, but they may be positioned at only one. Furthermore, the fuse 29 may be a tube fuse or a plug-in type like a blade fuse. In this case, a plug-in hole may be formed in the corresponding part of the housing 3, and the busbar 7 and connector 9 may be connected via the fuse by inserting the fuse from the outside.

According to the second embodiment, the same effects as the first embodiment can be obtained. Furthermore, by using the fuse 29, the in-vehicle unit and other components can be protected from overcurrent.

Next, a third embodiment will be described. Figure 6 is an exploded perspective view of the branch box 1a. The branch box 1a has substantially the same configuration as the branch box 1, but differs in that it uses a holder 5a and a bus bar 7a, among other things.

Figure 7(a) is a front view of the holder 5a. The busbar holding portion 19 protrudes from the holder 5 below the trunk cable mounting portion 17. That is, in a front view, the holder 5a has a roughly cross-shaped form. The busbar holding portion 19 is longer on the upper side than on the lower side of the trunk cable mounting portion 17 by the diameter of the trunk cable 11.

Furthermore, the trunk cable mounting section 17 is not continuous with the holder 5a in the depth direction (axial direction), and a notch 18 is formed in a part of it. That is, the trunk cable mounting section 17 is not formed in the notch 18, and the busbar holding section 19 is exposed between the trunk cable mounting sections 17.

Figure 7(b) is a side view of the busbar 7a. The busbar 7a has connector connection portions 21 formed on both the upper and lower sides of the trunk cable connection portion 23 relative to the busbar 7. In other words, the busbar 7a has a roughly H-shape.

Figure 8 is an axial cross-sectional view showing the branching structure 10b using the branching box 1a. The main cable connection portion 23 of the busbar 7a is positioned in the notch 18 of the holder 5a. The connector connection portion 21 of the busbar 7a is held by the busbar holding portions 19 above and below the main cable mounting portion 17 of the holder 5a.

Connectors 9 are connected to each connector connection point 21 of the busbar 7a. That is, connectors 9 are positioned above and below the main cable 11, facing each other in the axial direction, for a total of four locations.

According to the third invention, the same effects as the first invention can be obtained. Furthermore, by arranging connectors 9 on both the upper and lower sides of the main cable 11, even if the number of connectors 9 is increased, sufficient spacing between them can be ensured, improving connection workability and suppressing short circuits.

Next, a fourth embodiment will be described. Figure 9 shows the branch structure 10c according to the fourth embodiment. Figure 9(a) shows the state before the braided wire is attached, and Figure 9(a) shows the state after the braided wire 35 has been attached.

In the branching structure 10c, projections 31 are formed on at least a portion of the periphery of the cable penetration portion 25 of the housing 3, projecting outward in the axial direction. The projections 31 may be formed around the entire outer circumference of the cable penetration portion 25, but for example, as shown in the figure, they are formed on opposing arcs of the oval-shaped cable penetration portion 25. The braided wire 35 can be fixed to the housing 3 by covering the projections 31 and placing the band 33 around the outer circumference of the braided wire 35. The joining of the braided wire 35 and the projections 31 is not limited to the band 33; welding or brazing may also be used.

As mentioned above, since the housing 3 is made of metal, it can ensure shielding for the branch box. On the other hand, the main cable 11 is usually inserted into a braided wire or shielded conduit to ensure shielding. In this case, the braided wire 35 can be easily fixed to the projection 31, and the braided wire 35 and the housing 3 can be electrically connected, eliminating the need to ground the braided wire 35 separately using an earth wire or the like.

According to the fourth embodiment, the same effects as the first embodiment can be obtained. Furthermore, since the braided wire 35 can be easily fixed to the housing 3, the shielding of the entire circuit, including the branch box, can be easily ensured.

The embodiments of the present invention have been described above with reference to the attached figures, but the technical scope of the present invention is not limited to the embodiments described above. It will be clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these will naturally also fall within the technical scope of the present invention.

For example, it goes without saying that each embodiment can be combined with others.

1, 1a... Branch box 3... Housing 5, 5a... Holder 7, 7a... Bus bar 9... Connector 10, 10a, 10b, 10c... Branch structure 11... Main cable 13... Conductor 15... Sheath 17... Main cable mounting section 18... Notch 19... Bus bar holding section 21... Connector connection section 23... Main cable connection section 25... Cable penetration section 27... Connector fixing section 29... Fuse 31... Protrusion 33... Band 35... Braided wire

Claims (11)

A branch box for the main power supply circuit of an automobile,
The casing and
A holder positioned inside the aforementioned housing,
A bus bar held by the holder,
The connectors arranged in the aforementioned housing,
It is equipped with,
The busbar has a trunk cable connection portion that can be connected to a trunk cable and a connector connection portion that can be connected to the connector,
The holder has a trunk cable mounting section on which a trunk cable can be placed, and a busbar holding section that stands above the trunk cable mounting section and is sandwiched between a pair of busbars, having a thickness that ensures an insulating distance between the busbars.
The aforementioned busbar is characterized by being roughly T-shaped or roughly H-shaped in shape . The branch box according to claim 1, characterized in that a fuse is connected between the connector connection portion and the connector. The branch box according to claim 1 or 2 , characterized in that the holder is made of resin and is substantially in the shape of an inverted T or a cross when viewed from the front . The branch box according to any one of claims 1 to 3 , characterized in that the housing is made of metal. The housing has a cable penetration section through which a main cable can pass.
The branch box according to any one of claims 1 to 4 , characterized in that a projection is formed on at least a part of the periphery of the cable penetration portion, and a braided wire can be fixed to the projection. A branching structure using a branching box according to any one of claims 1 to 5 ,
At least one pair of trunk cables pass through the aforementioned enclosure,
A branching structure characterized in that, inside the housing, a portion of the covering of each of the main cables is removed, exposing the internal conductors, and the main cable connection portion of the busbar is joined. The branch structure according to claim 6 , characterized in that the conductor of the main cable and the main cable connection portion of the busbar are joined by welding. The branching structure according to claim 6 , characterized in that the conductor of the main cable and the main cable connection portion of the busbar are joined by crimping. The holder has a trunk cable mounting section on which a trunk cable can be placed, and a bus bar holding section that ensures an insulating distance between a pair of bus bars.
The branching structure according to any one of claims 6 to 8, characterized in that a pair of trunk cables are arranged on the trunk cable mounting section, the busbar holding section is arranged between the pair of trunk cables , and the busbar holding section is sandwiched between the pair of busbars. The branching structure according to claim 9, characterized in that the busbar holding portion and the pair of busbars are sandwiched between the pair of main cables. A method for constructing a branch structure using a branch box according to any one of claims 1 to 5 ,
Remove a portion of the sheathing from at least one pair of trunk cables to expose the internal conductors.
The main cable connection portion of the busbar is joined to the conductor of each of the main cables.
A method for constructing a branch structure, characterized by arranging the holder between a pair of busbars, sandwiching the busbar holding portion and the pair of busbars with a pair of main cables, and covering the busbars and the holder with the housing.