Cable routing structure

Abstract

To inhibit transmission of noise to a low-impedance load without using a high-impedance raw material for connection with the low-impedance load.SOLUTION: In wiring structure 1A, power supplied from a battery 20 which is a power source is branched into a plurality of systems such that the power is supplied to loads that are connected to the respective branch systems. Of closed paths for supplying power to the loads connected to the respective branch systems, a closed path for supplying power to a first load 30A that is a low-impedance load having the lowest impedance, has an impedance higher than the impedance of a closed path for supplying power to a second load 30B and a third load 30C that are high-impedance loads each having a higher impedance than the low-impedance load.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cable laying structure.

Background Art

[0002] As an invention for avoiding the influence of noise from a power line on a low-impedance load mounted on a vehicle, there is, for example, a cable laying structure of an electrical connection box disclosed in Patent Document 1. In this cable laying structure, a power line connected to a vehicle power supply is branched into a plurality of lines, and each of the plurality of lines is connected to a load by a bus bar. Further, in this cable laying structure, among the bus bars connecting the lines and the load, the bus bar connecting to the low-impedance load with the lowest impedance is made a bus bar having a higher impedance per unit length than the bus bar connecting to a load having a higher impedance than the low-impedance load.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, nickel or iron, which is a ferromagnetic material, is exemplified as a material of a bus bar having a high impedance per unit length. The bus bar is connected to a load or a line through a terminal plated with tin on copper, but if the material of the terminal and the material of the bus bar are different, there is a risk of dissimilar metal contact corrosion.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a technique for suppressing the transmission of noise to a low-impedance load without using a material having a high impedance for connection to the low-impedance load.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, the wiring structure according to the present invention is a wiring structure that branches power supplied from a power source into multiple systems and supplies power to loads connected to each branched system, wherein the impedance of the closed path that supplies power to the low-impedance load with the lowest impedance among the closed paths that supply power to the loads connected to the branched systems is higher than the impedance of the closed path that supplies power to the high-impedance load, which has a higher impedance than the low-impedance load.

[0007] In a cable routing structure according to one aspect of the present invention, the material of the cable routing member that supplies power from the system to the low-impedance load in a closed path including the low-impedance load is the same as the material of the cable routing member that supplies power from the system to the high-impedance load in a closed path including the high-impedance load.

[0008] In a cable routing structure according to one aspect of the present invention, an electrical junction box is provided for branching the power supplied from the power source to the plurality of systems, and in a closed path including the low-impedance load, the material of the cable supplying power from the system to the low-impedance load inside the electrical junction box is the same type of material as the terminals to which the cable supply and the cable supply connected to the low-impedance load are connected in the electrical junction box.

[0009] In a wiring structure according to one aspect of the present invention, an electrical junction box is provided for branching the power supplied from the power source to the plurality of systems, and in a closed path including the low impedance load, the wiring material that supplies power from the system to the low impedance load inside the electrical junction box is matched to the impedance of the low impedance load.

[0010] In a wiring structure according to one aspect of the present invention, an electrical junction box is provided for branching the power supplied from the power source to the plurality of systems, and the electrical junction box is provided with a magnetic sheet along a closed path including the low impedance load.

[0011] In a wiring structure according to one aspect of the present invention, an electrical junction box is provided for branching the power supplied from the power source to the plurality of circuits, and the housing of the electrical junction box is formed of a magnetic material.

[0012] In a wiring structure according to one aspect of the present invention, when the closed path that supplies power to the low-impedance load is located in a space with a relative permeability of 1, the value of S / d is 50 or more and 200 or less, where S is the area of ​​the closed path and d is the thickness of the closed path.

[0013] In a wiring structure according to one aspect of the present invention, when at least a portion of the closed path that supplies power to the low-impedance load is located in a space with a relative permeability of 50 or more, the value of S / d is 25 or more and 200 or less, where S is the area of ​​the closed path and d is the thickness of the closed path. [Effects of the Invention]

[0014] According to the present invention, the transmission of noise to a low-impedance load can be suppressed without using a high-impedance material for connection to the low-impedance load. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a diagram showing the schematic configuration of the cable routing structure according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram of the first closed path. [Figure 3] Figure 3 is a schematic diagram of the second closed path. [Figure 4] Figure 4 is a schematic diagram of the third closed path. [Figure 5] Figure 5 shows the simulation results for a closed path. [Figure 6] Figure 6 shows an example of the arrangement of magnetic sheets in an electrical junction box according to the second embodiment. [Figure 7] Figure 7 shows the simulation results for a closed path.

Best Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail while referring to the accompanying drawings. Note that the present invention is not limited by the embodiments described below. Also, in the description of the drawings, the same or corresponding elements are appropriately assigned the same reference numerals. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationships of each element may be different from the actual ones. There may also be parts where the dimensional relationships and ratios between the drawings are different from each other.

[0017] [First Embodiment] FIG. 1 is a diagram showing a schematic configuration of a cable routing structure according to a first embodiment of the present invention. The cable routing structure 1A is a structure in which an electrical connection box 10A installed in an automobile, a battery 20, a first load 30A, a second load 30B, and a third load 30C are electrically connected by a cable material.

[0018] The first load 30A is, for example, a device such as an ECU (Electronic Control Unit), a car audio, or a display device that has a lower impedance than the second load 30B and the third load 30C. The first load 30A is connected to the ground GND, connected to a terminal T31 provided in the electrical connection box 10 via an electric wire L51, and connected to a terminal T41 provided in the electrical connection box 10A via an electric wire L61. The first load 30A is an example of a low impedance load having the lowest impedance among the first load 30A, the second load 30B, and the third load 30C.

[0019] The second load 30B is, for example, a lighting device such as a lamp that has a higher impedance than the first load 30A. The second load 30B is connected to the ground GND, connected to a terminal T32 provided in the electrical connection box 10 via an electric wire L52, and connected to a terminal T42 provided in the electrical connection box 10A via an electric wire L62. The second load 30B is an example of a high impedance load having a higher impedance than the first load 30A.

[0020] The third load 30C is, for example, a device such as a door lock, an electric mirror, an inverter, etc. that uses a motor with a higher impedance than the first load 30A. The third load 30C is connected to the ground GND, connected to the terminal T33 provided in the electrical connection box 10 via the electric wire L53, and connected to the terminal T43 provided in the electrical connection box 10A via the electric wire L63. The third load 30C is an example of a high-impedance load with a higher impedance than the first load 30A.

[0021] The battery 20 is a secondary battery installed in the vehicle. The battery 20 is charged by an alternator (not shown) installed in the vehicle and supplies power to the first load 30A, the second load 30B, and the third load 30C via the electrical connection box 10A. The positive electrode of the battery 20 is connected to the terminal T11 provided in the electrical connection box 10A via the electric wire L1. The negative electrode of the battery 20 is connected to the terminal T21 provided in the electrical connection box 10A via the electric wire L71, connected to the terminal T22 provided in the electrical connection box 10A via the electric wires L71 and L72, and connected to the terminal T23 provided in the electrical connection box 10A via the electric wires L71 and L73.

[0022] The electrical connection box 10A is a device that supplies the power supplied from the battery 20 to the first load 30A, the second load 30B, and the third load 30C. The electrical connection box 10A includes a metal housing 101, terminals T11, T12, T21 to T23, T31 to T33, T41 to T43 arranged in the housing 101, busbars L31 to L33, and busbars L41 to L43. Further, the electrical connection box 10A includes a DC / DC converter 102 and a power distribution circuit 103.

[0023] The DC / DC converter 102 is a device that converts the DC voltage from the battery 20. The DC / DC converter 102 is connected to the terminal T11 and the terminal T12 connected to the ground GND. Also, the DC / DC converter 102 is connected to the power distribution circuit 103 and supplies the power with the voltage converted to the power distribution circuit 103.

[0024] The power distribution circuit 103 is a circuit that distributes the power supplied from the DC / DC converter 102 and controls the supply of the distributed power to the first load 30A, the second load 30B, and the third load 30C.

[0025] Busbars L31-L33 and L41-L43 are examples of wiring materials and are conductors capable of conducting large currents. Busbar L31 connects the power distribution circuit 103 to terminal T31, busbar L32 connects the power distribution circuit 103 to terminal T32, and busbar L33 connects the power distribution circuit 103 to terminal T33. Power supplied via busbar L31 is supplied to the first load 30A via terminal T31 and wire L51, power supplied via busbar L32 is supplied to the second load 30B via terminal T32 and wire L52, and power supplied via busbar L33 is supplied to the third load 30C via terminal T33 and wire L53. Busbar L41 connects terminal T21 to terminal T41, busbar L42 connects terminal T22 to terminal T42, and busbar L43 connects terminal T23 to terminal T43.

[0026] Furthermore, it is preferable that the materials of busbars L31-L33 and L41-L43 be the same type of material as the terminals to which they are connected, in order to prevent galvanic corrosion. Also, it is preferable that the terminals that are crimped onto wires L1, L51-L53, L61-L63 and L71-L73 and connected to the terminals of electrical junction box 10A are the same type of material as the terminals of electrical junction box 10A to which they are connected, in order to prevent galvanic corrosion. In addition, it is preferable that the material of the wiring material connected to the first load 30A be substantially the same as the material of the wiring material connected to the second load 30B and the wiring material connected to the third load 30C.

[0027] Wires L1, L2, L51-L53, L61-L63, and L71-L73 are examples of wiring materials, such as flat wires, flat wires, round wires, or combinations thereof, in the form of stranded wires. Wire L71 is connected to the negative terminal of battery 20. Wire L72 is connected to terminal T22 and wire L71, and wire L73 is connected to terminal T23 and wire L71.

[0028] In the wiring structure 1A, three closed paths are formed by the aforementioned wiring material, the aforementioned terminals, battery 20, DC / DC converter 102, power distribution circuit 103, and the first load 30A to the third load 30C.

[0029] Figure 2 is a schematic diagram of a first closed path RT1, which is an example of a closed path. The first closed path RT1 is a path from the positive terminal of the battery 20 to the negative terminal of the battery 20 via wire L1, terminal T1, DC / DC converter 102, wire L2, power distribution circuit 103, busbar L31, terminal T31, wire L51, first load 30A, wire L61, terminal 41, busbar L41, terminal T21, and wire L71. The first closed path RT1 functions as a coil with the first region AR1, which is hatched in Figure 2, as its cross-section, and therefore has an inductance component, which, together with the resistance component of the first closed path RT1, functions as a low-pass filter. Preferably, the impedance of the wiring materials constituting the first closed path RT1 is matched with the impedance of the first load 30A.

[0030] Figure 3 is a schematic diagram of a second closed path RT2, which is an example of a closed path. The second closed path RT2 is a path from the positive terminal of the battery 20 to the negative terminal of the battery 20 via wire L1, terminal T1, DC / DC converter 102, wire L2, power distribution circuit 103, busbar L32, terminal T32, wire L52, second load 30B, wire L62, terminal 42, busbar L42, terminal T22, wire L72, and wire L71. The second closed path RT2 also functions as a coil with the second region AR2, shown in hatching in Figure 3, as its cross-section, and therefore has an inductance component, which, together with the resistance component of the second closed path RT2, functions as a low-pass filter. Preferably, the impedance of the wiring materials constituting the second closed path RT2 is matched with the impedance of the second load 30B.

[0031] Figure 4 is a schematic diagram of a third closed path RT3, which is an example of a closed path. The third closed path RT3 is a path from the positive terminal of the battery 20 to the negative terminal of the battery 20 via wire L1, terminal T1, DC / DC converter 102, wire L2, power distribution circuit 103, busbar L33, terminal T33, wire L53, third load 30C, wire L63, terminal 43, busbar L43, terminal T23, wire L73 and wire L71. The third closed path RT3 also functions as a coil with the third region AR3, which is hatched in Figure 4, as its cross-section, and therefore has an inductance component, and together with the resistance component of the third closed path RT3 it functions as a low-pass filter. Preferably, the impedance of the wiring materials constituting the third closed path RT3 is matched with the impedance of the third load 30C.

[0032] The inductance of the closed path described above is determined by the permeability, the area within the closed path, and the thickness of the wiring material that makes up the thickness of the closed path, and can be increased by increasing the area within the closed path. In wiring structure 1A, the thickness of the wires and busbars, which are the wiring materials, is the same in each closed path, and the area of ​​the first region AR1 is larger than that of the second region AR2, and the area of ​​the first region AR1 is larger than that of the third region AR3. As a result, the inductance of the low-pass filter formed by the first closed path RT1 is greater than the inductance of the low-pass filter formed by the second closed path RT2, and is greater than the inductance of the low-pass filter formed by the third closed path RT3.

[0033] Although the first load 30A is a low-impedance load, increasing the inductance of the first closed path RT1, which acts as a low-pass filter, lowers the cutoff frequency of the low-pass filter, thereby suppressing the transmission of high-frequency noise to the first load 30A, which is a low-impedance load. In addition, since the impedance of the busbar L31 and the wire L61 that supply power to the first load 30A are matched with the impedance of the first load 30A, the generation of surges due to impedance mismatch between the load and the wiring can be suppressed.

[0034] Incidentally, if the area of ​​the first region AR1 is small, the cutoff frequency will not decrease, and noise will be transmitted to the first load 30A. On the other hand, increasing the area of ​​the first region AR1 will decrease the cutoff frequency, but space will be required to obtain a large area within the vehicle, making it difficult to route the wiring materials that constitute the first closed path RT1. Therefore, the inventors of the present invention have investigated a preferred area for the first region AR1.

[0035] Figure 5 is a graph showing the simulation results of the relationship between the area S and thickness d of a closed path and the path inductance, and the relationship between this path inductance and the cutoff frequency of the closed path acting as a low-pass filter. In the graph shown in Figure 5, the path inductance when the area S / thickness d is increased by 12.5m increments from 12.5m to 225m while keeping the thickness d constant is shown as a triangle, and the cutoff frequency of the low-pass filter at this inductance is plotted as a circle.

[0036] As shown in Figure 5, if the area S / thickness d is reduced to less than 50m, the cutoff frequency increases, and there is a risk of noise being transmitted to the first load 30A. Also, in order to lower the cutoff frequency, it is necessary to increase the area S, but if the area S / thickness d exceeds 200m, the length of the wires forming the first closed path RT1 also increases, making it difficult to route the wires forming the closed path to the vehicle. Therefore, in this embodiment, it is preferable to set the area S / thickness d to be between 50m and 200m.

[0037] [Second Embodiment] Next, a second embodiment of the present invention will be described. In the second embodiment, the configuration of the electrical junction box differs from that of the first embodiment. As other configurations are the same as in the first embodiment, the same reference numerals are used for the same configurations as in the first embodiment, and their descriptions are omitted. In the following description, the differences from the first embodiment will be explained.

[0038] The electrical junction box 10B according to the second embodiment differs from the electrical junction box 10A in that it includes a magnetic sheet 104, which is a magnetic sheet. Figure 6 is a schematic diagram showing an example of the arrangement of the magnetic sheet 104 in the electrical junction box 10B. Note that in Figure 6, the battery 20, the first load 30A, the second load 30B, and the third load 30C are omitted from the illustration to avoid making the drawing complicated. As shown in Figure 6, when the first closed path RT1 is along the top and bottom surfaces of the housing 101, the magnetic sheet 104 is arranged on the top and bottom surfaces inside the housing 101. It is preferable that the magnetic permeability of the magnetic sheet 104 is 50 or higher.

[0039] By placing the magnetic sheet 104 along the first closed path RT1 in the housing 101, the inductance component of the first closed path RT1 increases compared to when the magnetic sheet 104 is not placed. When the inductance component of the first closed path RT1 increases, the cutoff frequency of the first closed path RT1 as a low-pass filter decreases, so the area of ​​the first region AR1 can be made smaller than when the magnetic sheet 104 is not placed in the housing 101.

[0040] Figure 7 is a graph showing the simulation results of the relationship between the area S and thickness d of the closed path and the path inductance when the magnetic sheet 104 is placed in the housing 101, and the relationship between this path inductance and the cutoff frequency of the closed path acting as a low-pass filter. In the graph shown in Figure 7, the path inductance when the area S / thickness d is increased by 12.5m increments from 12.5m to 225m while keeping the thickness d constant is shown as a triangle, and the cutoff frequency of the low-pass filter at this inductance is plotted as a circle. In this simulation, the relative permeability of the magnetic sheet 104 is set to 50.

[0041] According to the graph in Figure 7, when the area S / thickness d is 200, the cutoff frequency is 63 Hz, which suppresses the transmission of noise due to fluctuations in the power supply voltage to the first load of 30 A.

[0042] Furthermore, the magnetic sheet 104 may be placed not only in the position shown in Figure 6, but also on the front and rear sides of the housing 101. Also, if the first closed path RT1, the second closed path RT2, and the third closed path RT3 are located along the front and rear sides of the housing 101 shown in Figure 6, the magnetic sheet 104 may also be placed on the front and rear sides of the housing 101 shown in Figure 6. In the second embodiment, instead of arranging the magnetic sheet 104, the housing 101 may be formed from a magnetic material and magnetized.

[0043] [Differentiation] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be implemented in various other forms. For example, the present invention may be implemented by modifying the embodiments described above as follows. The embodiments described above and the following modifications may be combined with each other. The present invention is also included in configurations that appropriately combine the components of each embodiment and each modification described above. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, broader embodiments of the present invention are not limited to the embodiments and modifications described above, and various modifications are possible.

[0044] In this invention, the loads connected to the electrical junction box 10A are not limited to the first load 30A, the second load 30B, and the third load 30C, and other loads may be connected. If other loads are connected, the area of ​​the closed path including the load with the lowest impedance is maximized.

[0045] In the embodiment described above, the wiring structure 1A is applied to an automobile, but the wiring structure is not limited to automobiles and can also be applied to electrical equipment that branches power and supplies it to low-impedance loads and high-impedance loads. [Explanation of Symbols]

[0046] 1A Cable routing structure 10A, 10B electrical junction box 20 batteries 30A 1st load 30B 2nd load 30C 3rd load 101 cabinets 102 DC / DC Converter 103 Power distribution circuit 104 Magnetic Sheet AR1 1st area AR2 2nd area AR3 3rd area L1, L2, L51~L53, L61~L63, L71~L73 Electric wire L31-L33, L41-L43 Bus Bar RT1 First Closed Path RT2 Second Closed Path RT3 Third Closed Path Terminals T11, T12, T31-T33, T41-T43

Claims

1. A wiring structure that branches power supplied from a power source into multiple systems and supplies power to loads connected to each branched system, The system includes an electrical junction box that branches the power supplied from the power source to the multiple circuits, Among the closed paths that supply power to loads connected to the branched system, the impedance of the first closed path that supplies power to the lowest impedance load is higher than the impedance of the second closed path that supplies power to the highest impedance load, which has a higher impedance than the low impedance load. The region of the first closed path and the region of the second closed path are along the surface of the electrical junction box. When the area of ​​the first closed path is S and the thickness of the first closed path is d, the value of S / d is 25 or more and 200 or less. The relative permeability is 50 or more, and the first closed path is sandwiched between magnetic sheets along the first closed path. Cable routing structure.

2. The magnetic sheet is arranged on the upper and lower surfaces of the electrical connection box, In the first closed path including the low-impedance load, the material of the wiring that supplies power from the system to the low-impedance load is the same as the material of the wiring that supplies power from the system to the high-impedance load in the second closed path including the high-impedance load. The cable routing structure according to claim 1.

3. The magnetic sheet is arranged on the upper and lower surfaces of the electrical connection box, In the first closed path including the low-impedance load, the material of the wiring that supplies power from the system to the low-impedance load inside the electrical junction box is the same type of material as the terminals to which the wiring and the wiring connected to the low-impedance load are connected in the electrical junction box. The cable routing structure according to claim 1.

4. The housing of the electrical junction box is formed of a magnetic material. The cable routing structure according to claim 1.

5. A wiring structure that branches power supplied from a power source into multiple systems and supplies power to loads connected to each branched system, The system includes an electrical junction box that branches the power supplied from the power source to the multiple circuits, Among the closed paths that supply power to loads connected to the branched system, the impedance of the closed path that supplies power to the lowest impedance load is higher than the impedance of the closed path that supplies power to the highest impedance load, which has a higher impedance than the lowest impedance load. In the closed path including the low-impedance load, the wiring that supplies power from the system to the low-impedance load inside the electrical junction box is matched to the impedance of the low-impedance load. Cable routing structure.

6. A wiring structure that branches power supplied from a power source into multiple systems and supplies power to loads connected to each branched system, The system includes an electrical junction box that branches the power supplied from the power source to the multiple circuits, Among the closed paths that supply power to loads connected to the branched system, the impedance of the closed path that supplies power to the lowest impedance load is higher than the impedance of the closed path that supplies power to the highest impedance load, which has a higher impedance than the lowest impedance load. The electrical junction box includes a magnetic sheet along the closed path containing the low-impedance load. Cable routing structure.

7. When the closed path that supplies power to the low-impedance load is located in a space with a relative permeability of 1, the value of S / d is 50 or more and 200 or less, where S is the area of ​​the closed path and d is the thickness of the closed path. The cable routing structure according to claim 5 or claim 6.

8. When at least a portion of the closed path that supplies power to the low-impedance load is located in a space with a relative permeability of 50 or more, the value of S / d is 25 or more and 200 or less, where S is the area of ​​the closed path and d is the thickness of the closed path. The cable routing structure according to claim 5 or claim 6.

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