Methods for determining the order of wire insertion and the equipment used for determining the order of wire insertion.

Abstract

In the present invention, connectors are divided into a plurality of groups and branch line connectors that branch from a common branching point are assigned to the same group (S13). A priority is assigned to each group of connectors on the basis of the number of branch lines, the number of electrical wire circuits and so forth (S15). Using the obtained results, the order in which electrical wires that constitute a wire harness are to be inserted into connector housings is sequentially determined (S16 to S19). The insertion order of the electrical wires can be efficiently determined so that the occurrence of entanglements is reduced by making the priority high for electrical wires that pass through branch points where entanglement is likely to occur. A plurality of electrical wires are divided into different circuits for each of the groups to which connection-origin connectors and connection-destination connectors of the electrical wires belong, and the priority of each group is determined in accordance with the number of circuits included in the group.

Description

This invention relates to a method and apparatus for determining the wire insertion order that can be used when manufacturing wire harnesses. For example, a wire harness installed in a vehicle is used to connect the vehicle's power supply to various electrical components on the vehicle, or to connect multiple electrical components to each other. Such a wire harness includes, for example, an assembly of many wires and a number of connectors connected to the end of each wire, as shown in Figure 10 of Patent Document 1. In addition, a wire harness may be constructed by combining multiple sub-harnesses. A connector consists of multiple terminals for electrical connection and a connector housing formed with multiple cavities to accommodate these terminals. When manufacturing a wire harness or sub-harness, terminals are attached to the ends of each wire or wire bundle, and then the terminals of each wire are inserted into the cavities of the connector housing to integrate them (see Figures 7 and 8 of Patent Document 1). Conventionally, this terminal and wire insertion process has been carried out by using a manufacturing robot to grasp each wire or terminal and sequentially inserting the wires with terminals into the connector housing placed on a predetermined table. For example, the wire harness design method shown in Patent Document 1 provides a technique for significantly shortening the time required to develop a new wire harness. Specifically, the wire harness Cmp is divided into multiple subassemblies Sub1 to Sub3, and the three-dimensional shapes of these subassemblies Sub1 to Sub3 are compositely displayed on a predetermined display screen while arranged on a harness assembly workbench 16. Furthermore, the display position of each subassembly Sub1 to Sub3 can be arbitrarily moved, for example, in the Z-axis direction. This makes it possible to easily simulate the assembly sequence of multiple subassemblies Sub1 to Sub3 visually without creating a prototype. Furthermore, Patent Document 2 provides a wire connection support device that enables the rapid, accurate, and continuous execution of wire connection work set for multiple stations on the same drawing board, based on connection support information built in a single database. Japanese Patent Publication No. 2003-132102 Japanese Patent Publication No. 2002-359049 By the way, in the case of a wire harness used in a vehicle or the like, it is necessary to connect various electrical components arranged at various locations to each other via the wire harness. Therefore, such a wire harness has at least one trunk line portion, a plurality of branch line portions branched from the trunk line portion, and a plurality of connectors connected to ends of the trunk line portion or the branch line portions. That is, the paths through which each electric wire constituting the wire harness passes are intricately intertwined, and the wiring direction of each electric wire changes at the branching points. In the wire harness as described above, since a large number of electric wires overlapping each other are wired along their respective independent paths, entanglement is likely to occur between adjacent electric wires, particularly at the branching points. When entanglement occurs between electric wires, it becomes difficult to bend the shape of the wire harness at that location, and the workability of the wiring deteriorates. In addition, due to the entanglement, the path length of each electric wire becomes longer, and there may be a shortage of margin in the wire length. In order to eliminate such entanglement between electric wires, it was necessary for the operator to repeatedly try and error manually regarding the design change of the wire harness, and the design work could not be carried out efficiently. Also, regarding the work of inserting a large number of terminal-attached electric wires constituting the wire harness into each cavity of the connector housing, it has been conventionally carried out regularly according to a predetermined order. For example, when inserting a large number of terminal-attached electric wires into a connector housing having N cavities arranged horizontally in each of the upper and lower rows in the vertical direction, first, the cavities in the lower row are selected, and the electric wires are inserted into each cavity in the lower row in order from left to right. When this is completed, the cavities in the upper row are selected, and the electric wires are inserted into each cavity in the upper row in order from left to right. By repeating such regular work, all the electric wires can be inserted into each connector housing. The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a method for determining the order of inserting electric wires and a device for determining the order of inserting electric wires that can improve the efficiency of the work for suppressing entanglement between electric wires occurring near the branching points of the wire harness. To achieve the aforementioned objectives, the wire insertion order determination method according to the present invention is characterized by the following (1) to (7): (1) A wire insertion order determination method for determining the order in which each of the multiple terminal wires constituting the main line section or the branch section is inserted into the connector housing of a plurality of connectors when manufacturing a wire harness having at least one main line section, a plurality of branch line sections branched from the main line section, and a plurality of connectors connected to the ends of the main line section or the branch line sections, comprising: a first step of dividing the plurality of connectors included in the wire harness into a plurality of groups according to predetermined rules; a second step of assigning a priority to the divided plurality of groups that reflects the wire entanglement characteristics at the branch section of the wire harness; and a third step of determining the insertion order of each wire connecting the plurality of connectors within a group and the connectors belonging to different groups, based on the priority assigned to each group. (2) The method for determining the order of wire insertion described in (1) above, wherein in the second step, the plurality of wires constituting the wire harness are divided into different circuits for each group to which the source connector and destination connector belong, and the priority of each group is determined according to the number of circuits included. (3) The method for determining the order of wire insertion described in (1) above, wherein in the second step, the priority of the group corresponding to the branch line portion is determined according to the number of branch lines of the branch line portion that branched from the same point on the wire harness. (4) The method for determining the order of wire insertion described in (3) above, wherein in the second step, a higher priority is assigned to the branching point on the main line portion, and a lower priority is assigned to the branching point as it approaches the end of the wire harness. (5) The method for determining the order of wire insertion described in (1) above, wherein in the third step, the differences in the branching direction of each wire at the branching point are distinguished, and the insertion order is determined considering the branching priority for each circuit within the group. (6) The method for determining the wire insertion order described in (5) above, wherein the third step reflects the difference in the stacking order of each wire in the insertion order.(7) The method for determining the wire insertion order described in (1) above, wherein the first step involves assigning connectors connected to multiple branch wires branched from a common branch point to a common group. The wire insertion order determination method of the configuration described in (1) above makes it easier to suppress entanglement between wires that occurs near branching points in the wire harness. For example, when assigning connectors connected to the ends of each of several branch wires branching from the same point in the main line to the same group, priority can be assigned to the group by considering the number of branches at a specific branching point that affects entanglement of wires related to that group, and the number of wires in the branch wires. Then, by inserting each wire in an order that changes according to the priority, it becomes possible to reduce entanglement between wires. The wire insertion order determination method of the configuration described in (2) above makes it possible to estimate the likelihood of entanglement by considering the number of circuits, that is, by distinguishing the number of wires with different routing paths and directions from each other, and to determine the priority of each group. The wire insertion order determination method of the configuration described in (3) above makes it possible to determine the priority of each group by considering the number of branching points at the same location. In other words, as the number of branching points increases, the frequency of numerous wires with different directions becoming entangled with each other and stacking in close proximity increases, so it is desirable to prioritize the insertion order. According to the wire insertion order determination method of configuration (4) above, a higher priority can be assigned to branching points where tangling is more likely to occur. In other words, the main line has the most wires, and the number of wires decreases at the branch lines at the end, so a priority can be assigned according to the likelihood of tangling. According to the wire insertion order determination method of configuration (5) above, a priority can be determined for each circuit for multiple wires connected to each connector within the same group, and each wire can be inserted in order for each circuit. In other words, multiple wires going in the same direction can be stacked in order and inserted into the connector housing, so the wires are stacked in an orderly manner, preventing tangling. According to the wire insertion order determination method of configuration (6) above, the insertion order is determined considering the stacking order of adjacent wires, so the occurrence of tangling at branching points can be suppressed. According to the wire insertion order determination method of configuration (7) above, it is possible to assign a priority to each group considering the likelihood of tangling at each branching point. Therefore, it becomes possible to efficiently determine the optimal insertion order for each wire. To achieve the aforementioned objectives, the wire insertion order determination device according to the present invention is characterized by the following (8): (8) A wire insertion order determination device that assists in determining the order in which to insert each of the multiple terminal wires constituting the main line section or the branch section into the connector housings of a plurality of connectors when manufacturing a wire harness having at least one main line section, a plurality of branch line sections branched from the main line section, and a plurality of connectors connected to the ends of the main line section or the branch line sections, comprising: a first step of dividing the plurality of connectors included in the wire harness into a plurality of groups according to predetermined rules; a second step of assigning a priority to the divided plurality of groups that reflects the wire entanglement characteristics at the branch section of the wire harness; and a third step of determining the insertion order of each wire connecting the plurality of connectors within a group and the connectors belonging to different groups, based on the priority assigned to each group. According to the wire insertion order determination device configured as described in (8) above, the control unit can assist in determining the insertion order of each wire or automatically determine the insertion order of each wire through processing, making it easier to suppress entanglement between wires that occurs near branching points of the wire harness. The wire insertion order determination method and wire insertion order determination device of the present invention make it possible to streamline the work required to suppress tangling between wires near branching points in a wire harness. In other words, the order in which each wire is inserted into the connector housing can be determined in an order that minimizes tangling. The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by referring to the accompanying drawings and reading through the embodiments for carrying out the invention described below (hereinafter referred to as "embodiments"). Figure 1 is a flowchart showing the processing procedure for determining the wire insertion order. Figure 2 is a plan view showing a specific example of the overall configuration of a wire harness arranged on a jig. Figure 3 is a schematic diagram showing a specific example of the state in which each connector of the wire harness shown in Figure 2 is divided into groups. Figure 4 is a schematic diagram showing a specific example of the number of circuits of a wire that is common to both the source and destination connector groups. Figure 5 is a schematic diagram showing the correspondence between the circuit groups of a wire that is common to both the source and destination connector groups and each connector group. Figure 6 is a schematic diagram showing a specific example of the insertion order for each circuit group when inserting wires into each connector of the wire harness shown in Figure 2. Specific embodiments of the wire insertion order determination method and wire insertion order determination device of the present invention will be described below with reference to the figures. <Explanation of a specific example of the wire harness configuration> Figure 2 shows a specific example of the overall configuration of the wire harness 20 placed on the jig 10. That is, numerous wires for electrically connecting electrical components placed at various locations on the vehicle are routed to pass through predetermined paths, and the length of each wire and the position of the wire ends are aligned. These wires are then stacked and bundled together to form a wire harness 20 or a part thereof, which is placed on the jig 10 as shown in Figure 2. Furthermore, the ends of each wire constituting the wire harness 20 are connected to a specific connector designated in advance. In practice, a metal terminal is attached to the end of each wire, and each terminal is inserted together with the wire into an opening (cavity) of the connector housing that constitutes the connector. The wire harness 20 shown in Figure 2 has a main line 21 as the main section where the most wires are stacked. The wire harness 20 also has branch lines 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H, 22I, 22J, and 22K that branch off from the main line 21. The end of branch wire 22A is connected to connector 24A. That is, the terminals (not shown) at the ends of one or more wires constituting branch wire 22A are inserted together with the wires into a cavity provided in the connector housing of connector 24A and secured. Similarly, the ends of branch wires 22B, 22C, 22D, 22E, 22F, 22G, 22H, 22I, 22J, and 22K are connected to connectors 24B, 24C, 24D, 24E, 24F, 24G, 24H, 24I, 24J, and 24K, respectively. The right end of main wire 21 is connected to connector 24L. The wire harness 20 shown in Figure 2 has branching sections 23A, 23B, 23C, 23D, and 23E provided at multiple locations. For example, some of the numerous wires passing through the main line 21 are branched off from the main line 21 at branching section 23D to become branch lines 22A and 22B. Also, wires branched off from the main line 21 at branching section 23E constitute branch line 22C. Also, wires branched off from the main line 21 at branching section 23A constitute branch lines 22D and 22E. Also, wires branched off from the main line 21 at branching section 23B constitute branch lines 22F, 22G, and 22H. Also, wires branched off from the main line 21 at branching section 23C constitute branch lines 22I and 22J. Also, wires branched off from the main line 21 at branching section 23F constitute branch line 22K. <Explanation of wire entanglement> The wire harness 20, as shown in Figure 2, is an assembly of numerous wires stacked in sequence, allowing for an orderly arrangement of the wires. However, it is impossible to arrange the numerous wires in an orderly manner at every point of the wire harness 20. That is, since the wire harness 20 is composed of a collection of wires that pass through different paths, at each branching point 23A, 23B, 23C, 23D, and 23E, the orientation of adjacent wires may change, or the stacking order may be reversed. Therefore, at branching points 23A, 23B, 23C, 23D, and 23E, the wire harness 20 may be formed with adjacent wires entangled. In other words, wire entanglement is likely to occur near branching points. Furthermore, when there are numerous connectors 24A to 24L, as shown in Figure 2 of the wire harness 20, simply inserting each wire into the cavity in a regular order according to the arrangement of each connector and the arrangement of cavities within the connector housing makes it difficult to eliminate tangling of wires at branching points in the wire harness 20. In other words, if the insertion order of numerous wires is determined according to a regular order, it is impossible to avoid tangling caused by changes in the direction of wires at branching points or changes in the stacking order. If entanglement occurs between the wires constituting the wire harness 20, the overall shape of the wire harness 20 becomes difficult to bend, which is expected to worsen workability when installing the wire harness 20 in a vehicle. In addition, because each wire will have to pass through an extra path due to the entanglement, there is a possibility that there will be insufficient wire length. <Explanation of methods to reduce wire entanglement> In order to reduce entanglement between wires in the wire harness 20, it is necessary to suppress frequent changes in direction or changes in the stacking order between adjacent wires at the branching points of the wire harness 20. Specifically, it is possible to reduce entanglement between wires by devising and optimizing the insertion order when inserting each wire constituting the wire harness 20 into each connector housing. <Method for determining the optimal wire insertion order> <Grouping of each connector: S13> In order to optimize the wire insertion order, it is considered best to prioritize the order of connections in areas where tangling is more likely to occur. Therefore, first, the numerous connectors included in the wire harness 20 are divided into several groups according to the following rules. (Rule 1): Connectors connected to branch lines that branch off from the same branching point are assigned to the same connector group (to assign the same priority). (Rule 2): The number of connectors in one group is limited to an upper limit (e.g., 10). (Rule 3): The number of circuits in one group is limited to an upper limit (e.g., 30 circuits). (Rule 4): If the difference in branch length from the main line 21 is greater than or equal to a predetermined value (e.g., 500 mm), it is assigned to a different group. By grouping connectors according to these rules, it becomes possible to easily understand the stacking of wires at branching points where tangling can occur, as well as the flow of the circuit. <Specific examples of grouping each connector> Figure 3 shows a specific example of how each connector of the wire harness 20 shown in Figure 2 is divided into groups. For example, each of the connectors 24A, 24B, and 24C shown in Figure 2 is connected to a branch wire that branches off from a common branching point 23E, so they are assigned to connector group GrA as shown in Figure 3. Similarly, connectors 24D and 24E are assigned to connector group GrB as shown in Figure 3, connectors 24F, 24G, and 24H are assigned to connector group GrC, connectors 24I and 24J are assigned to connector group GrD, and connectors 24K and 24L are assigned to connector group GrE. <Circuit Grouping: S14> Figure 4 shows a list of the number of circuits for wires common to the source and destination connector groups. Since the specifications of the wire harness 20 to be manufactured are determined in advance, the number of wires (circuits) connecting a specific source connector and destination connector is known, for example. Therefore, these number of circuits are associated with the connector groups described above. The result is shown in Figure 4. For example, in the example shown in Figure 4, there are two wires connecting the source connector (FROM3) belonging to connector group GrA to the destination connector (TO3) also belonging to connector group GrA. Similarly, there are two wires connecting the source connector (FROM3) belonging to connector group GrA to the destination connector (TO3) belonging to connector group GrB. Likewise, there are six wires connecting the source connector of GrA to the destination connector of GrC, and three wires connecting the source connector of GrA to the destination connector of GrD. Furthermore, there are five wires connecting the source connector of GrB to the destination connector of GrC, and three wires connecting the source connector of GrB to the destination connector of GrE. The other circuits are as shown in Figure 4. Figure 5 visually represents the correspondence between the circuit group of a common wire and each connector group, where the connector groups at the source and destination of the connection are common. As shown in Figure 5, the wire harness 20 includes the following circuit groups: 31AA which connects within GrA, 31AB which connects between GrA and GrB, 31AC which connects between GrA and GrC, 31AD which connects between GrA and GrD, 31BC which connects between GrB and GrC, 31BE which connects between GrB and GrE, 31CC which connects within GrC, 31CD which connects between GrC and GrD, 31CE which connects between GrC and GrE, and 31DE which connects between GrD and GrE. Furthermore, circuit group 31AA has 2 circuits, circuit group 31AB has 2 circuits, circuit group 31AC has 6 circuits, circuit group 31AD has 3 circuits, circuit group 31BC has 5 circuits, circuit group 31BE has 3 circuits, circuit group 31CC has 1 circuit, circuit group 31CD has 14 circuits, circuit group 31CE has 5 circuits, and circuit group 31DE has 3 circuits. Furthermore, the circuit groups associated with connector group GrA are 31AA, 31AB, 31AC, and 31AD, so a total of 13 wires are included in connector group GrA. Similarly, the circuit groups associated with connector group GrB are 31AB, 31BC, and 31BE, so a total of 17 wires are included in connector group GrB. Likewise, a total of 37 wires are included in connector group GrC, a total of 28 wires are included in connector group GrD, and a total of 11 wires are included in connector group GrE. <Assignment of Priority: S15> When determining the insertion order of wires for each circuit group shown in Figure 5, a desirable priority can be determined for each connector group. That is, each wire connected to each connector belonging to the same connector group is connected to each branch wire branching from a common branching point, so the insertion order of the wires similarly affects the degree of wire entanglement at the branching point. In reality, the main line 21 on the wire harness 20 has many branches and many wire circuits, making it more prone to wire entanglement, so it needs to be given a higher priority. On the other hand, as you approach the end of the wire harness 20, the number of branches and the number of wire circuits tend to decrease, so wire entanglement is less likely to occur even if the priority is lower. Therefore, branches on the main line 21 should be considered with the highest priority, and the priority should be assigned so that it decreases as you approach the end. In the example shown in Figure 5, the priority of each connector group is determined in descending order of the number of circuits associated with that connector group. That is, since the number of circuits in each connector group GrA, GrB, GrC, GrD, and GrE is "13", "17", "37", "28", and "11", respectively, connector group GrC is assigned the highest priority. Connector group GrD is assigned the second highest priority, and connector group GrB is assigned the third highest priority. <Assignment of insertion order for each circuit group: S16-S18> Figure 6 shows a specific example of the insertion order for each circuit group when inserting wires into each connector of the wire harness 20 shown in Figure 2. In other words, according to the priority assigned to each connector group GrA to GrE as shown in Figure 5, the insertion order is determined in order from the circuit group connected to the connector group with the highest priority. Furthermore, the insertion order is determined by considering factors other than the priority of the connector group. For example, the stacking order when stacking each wire or sub-harness is also considered when determining the insertion order. Additionally, the priority of the insertion order is determined by distinguishing between different patterns, such as leftward flow, rightward flow, and straight-line flow at branching points. For example, among the circuit groups associated with the connector group GrC, which has the highest priority, circuit group 31CC can be determined to be the first to be inserted because both its source and destination are GrC. Also, circuit group 31AC, which connects GrA and GrC, can be determined to be the second to be inserted because it is associated with the connector group GrC, which has the highest priority. Similarly, circuit group 31BC, which connects GrB and GrC, can be determined to be the third to be inserted because it is associated with the connector group GrC, which has the highest priority. <Assignment of insertion order within circuit groups: S19> After assigning the insertion order for each circuit group as shown in Figure 6, the insertion order within each circuit group is determined. For example, circuit group 31AC, which is the second in the insertion order for each circuit group, contains the wires of "6" circuits as shown in Figure 5, so it is necessary to determine the insertion order for each of the wires of the "6" circuits. Furthermore, since each connector group contains multiple connectors, the source and destination connectors are not necessarily the same even within the same connector group. Therefore, for example, when determining the insertion order of the wires for circuit "6" within circuit group 31AC, the actual source and destination connectors of each wire are distinguished, and differences in patterns such as leftward flow, rightward flow, and straight-line flow due to branching within the group are also distinguished to determine the priority of the insertion order in a way that minimizes tangling. In addition, the stacking order when stacking the wires is also taken into consideration when determining the insertion order of each wire. <Explanation of specific processing procedure> Figure 1 shows the processing procedure for determining the wire insertion order. That is, when manufacturing a wire harness 20 as shown in Figure 2, a program including the processing procedure in Figure 1 is executed using a processing device (e.g., a personal computer) (not shown) to determine the order in which each of the numerous terminal-equipped wires constituting the wire harness 20 is inserted into the connector housing of the corresponding connector. Then, according to the order determined by the processing procedure in Figure 1, a manufacturing robot is used to grasp the corresponding wires or terminals in order and actually insert them into the corresponding connector housing. The details of each of the characteristic processing steps S13 to S19 in the processing procedure shown in Figure 1 have already been explained. The outline of each step in the processing procedure shown in Figure 1 is described below. In step S11, the processing device reads predetermined internal diagram data from a database that does not include illustrations and creates editing data to be used in the manufacture of the wire harness 20. This editing data includes a circuit list, a terminal list, and a component list. The circuit list includes a list of information representing the source and destination of each wire. The terminal list is a list of information representing the location and type of each connector connected to the wire harness 20. The component list is a list of information regarding the type, length, etc., of each component (wires, connector housings, terminals, etc.) that makes up the wire harness 20. In step S12, the processing unit reads information representing the configuration of the sub-harnesses that constitute a part of the wire harness 20 and creates data for each sub-harness. This data also includes a circuit list, a terminal list, and a component list. In step S13, the processing unit reads the routing information of the wire harness 20 from the database and groups the terminals. That is, as described above, it divides the group of connectors connected to each terminal of the wire harness 20 into multiple groups for each branch (see Figure 3). The routing information read includes, for example, the position information of each branch section 23A, 23B, 23C, 23D, 23E, 23F in the wire harness 20 shown in Figure 2, and information on the direction of branching for each branch line (right, left, straight, etc.). In step S14, the processing unit performs circuit grouping. That is, using the classification of the multiple connector groups GrA to GrE determined in S13, it identifies the number of circuits (number of wires) for each wire belonging to a connector group that has a common source and destination, and obtains the result shown in Figure 4. In addition, it displays visual information on the processing unit's screen, for example, as shown in Figure 5. This makes it possible for the operator of the processing unit to visually grasp the classification of the connector groups and the number of circuits of the wires connecting each part. In step S15, the processing unit uses the grouping results from S13 and S14 to determine the priority for each branching point according to predetermined rules. For example, as shown in Figure 5, after determining the number of circuits for each connector group, it assigns higher priority to each group in order of the number of circuits. Alternatively, one could assign higher priority to branching points closer to the center of the overall layout of the wire harness 20 (because they are likely to have a large number of wires). Furthermore, while the processing unit can automatically determine the priority according to predetermined rules, it is also possible for the operator to make the final priority decision from among multiple candidates, or for the operator to be able to modify the priority determined by the processing unit according to their input. In that case, it is desirable to display visual information, such as that shown in Figure 5, on the processing unit's screen so that the operator can easily grasp the status of the wire harness 20 visually. In step S16, the processing unit determines the insertion order for each circuit group, according to the priority determined in S15, for the circuit groups that pass through the branching point of the group assigned the highest priority. In the next step, S17, it determines the insertion order for each circuit group, for the circuit groups that pass through the branching point of the group assigned the second highest priority. Furthermore, in step S18, it determines the insertion order for each circuit group, for the circuit groups that pass through the branching point of the group assigned the third highest priority. The insertion order for the remaining circuit groups is determined using a similar process. As a result of the processing in S16 to S18, the entire insertion order for each circuit group is determined, for example, as shown in Figure 6. However, since each circuit group almost always contains multiple wires (circuits), it is necessary to further subdivide the insertion order in Figure 6 to determine the insertion order for each wire. In step S19, a further subdivided insertion order is determined based on the insertion order for each circuit group determined by the processes in S16 to S18. That is, for each of the one or more circuits (wires, etc.) contained within each circuit group, the insertion order within the circuit group is determined. In the S19 process, the insertion order is determined by setting priorities to minimize tangling of wires at each branching point. For example, priorities are set by considering the differences in the direction of travel from the branching point of each circuit (right, left, straight), or the insertion order for each circuit is determined based on the stacking order of each circuit to minimize tangling. In step S20, the processing unit identifies the presence or absence of joints in the wire harness 20. If joints are present, the process proceeds to step S21, where the insertion order data for each circuit created in S19 is edited and the order is rearranged. Specifically, the order is changed so that each circuit constituting the joint is inserted consecutively. In step S22, the processing unit identifies the presence or absence of special wires in the wire harness 20. If special wires are present, the process proceeds to step S23, where the insertion order data for each circuit created in S19 is edited and the order is rearranged. Specifically, the order is changed so that each circuit constituting the special wire is inserted consecutively. In step S24, the processing unit outputs data on the terminal (wire) insertion order for each circuit, which has been optimized by the processing described above. The data output in S24 is input to a manufacturing robot for the process of inserting each wire of the wire harness into the connector housing, and the contents of the data are reflected in the insertion order of each wire. Furthermore, the insertion order determined by the procedure shown in Figure 1 is designed to suppress tangling at the branching points of the wire harness 20, and therefore differs significantly from the regular insertion order that is generally adopted. In other words, by adopting the procedure shown in Figure 1, it is possible to suppress tangling between wires and construct a high-quality wire harness 20 compared to inserting each wire into the connector housing in a regular order. Herein, the features of the embodiments of the wire insertion order determination method and wire insertion order determination device according to the present invention described above are briefly summarized and listed below in (1) to (8). (1) A wire insertion order determination method for determining the order in which each of the multiple terminal wires constituting the main line section or the branch line section is inserted into the connector housing of the multiple connectors when manufacturing a wire harness (20) having at least one main line section (main line 21), a plurality of branch line sections (branch lines 22A to 22K) branching from the main line section, and a plurality of connectors (24A to 24L) connected to the ends of the main line section or the branch line sections, comprising: a first step (S13) of dividing the plurality of connectors included in the wire harness into a plurality of groups (GrA to GrE) according to predetermined rules; a second step (S15) of assigning a priority to the divided plurality of groups that reflects the wire entanglement characteristics at the branch sections (23A to 23F) of the wire harness; and a third step (S16 to S19) of determining the insertion order of each wire connecting the plurality of connectors within a group and the connectors belonging to different groups, based on the priority assigned to each group. A method for determining the order in which to insert a wire. (2) The method for determining the order in which to insert a wire according to (1) above, wherein in the second step, the plurality of wires constituting the wire harness are divided into different circuits for each group to which the source connector and the destination connector belong, and the priority of each group is determined according to the magnitude of the number of circuits included (S14, S15). (3) The method for determining the order in which to insert a wire according to (1) above, wherein in the second step, the priority of the group corresponding to the branch line portion is determined according to the magnitude of the number of branch lines of the branch line portion that branch off from the same location on the wire harness. (4) The method for determining the order in which to insert a wire according to (3) above, wherein in the second step, a high priority is assigned to the branching point on the main line portion, and a lower priority is assigned to the branching point as it approaches the end of the wire harness.(5) The wire insertion order determination method of (1) above, wherein in the third step, the differences in the branching direction of each wire at the branching point are distinguished, and the insertion order is determined considering the branching priority for each circuit within the group. (6) The wire insertion order determination method of (5) above, wherein in the third step, the differences in the stacking order of each wire are reflected in the insertion order. (7) The wire insertion order determination method of (1) above, wherein in the first step, connectors connected to multiple branch wires branched from a common branching point are assigned to a common group (see Figures 2 and 3). (8) A wire insertion order determination device for assisting in determining the order in which each of the multiple terminal wires constituting the main line section or the branch line section is inserted into the connector housing of a plurality of connectors when manufacturing a wire harness (20) having at least one main line section, a plurality of branch line sections branched from the main line section, and a plurality of connectors connected to the ends of the main line section or the branch line sections, comprising: a first step (S13) of dividing the plurality of connectors included in the wire harness into a plurality of groups according to predetermined rules; a second step (S15) of assigning a priority to the divided plurality of groups that reflects the wire entanglement characteristics at the branch section of the wire harness; and a third step (S16 to S19) of determining the insertion order of each wire connecting the plurality of connectors within a group and the connectors belonging to different groups, based on the priority assigned to each group. Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2014-191472 filed on September 19, 2014, the contents of which are incorporated herein by reference. The present invention has the effect of streamlining the work required to suppress entanglement between wires near branching points in wire harnesses. This present invention is useful for determining the wire insertion order and for use in manufacturing wire harnesses. 10 Jig 20 Wire harness 21 Main line 22A, 22B, 22C, 22D, 22E, 22F Branch line 22G, 22H, 22I, 22J, 22K Branch line 23A, 23B, 23C, 23D, 23E, 23F Branch section 24A, 24B, 24C, 24D, 24E, 24F Connector 24G, 24H, 24I, 24J, 24K, 24L Connector GrA, GrB, GrC, GrD, GrE Connector group 31AA Circuit group connecting within GrA 31AB Circuit group connecting GrA-GrB 31AC Circuit group connecting GrA-GrC 31AD Circuit group connecting GrA-GrD 31BC Circuit group connecting GrB-GrC 31BE Circuit group connecting GrB-GrE 31CC Circuit group connecting within GrC 31CD Circuit group connecting GrC-GrD 31CE Circuit group connecting GrC-GrE 31DE Circuit group connecting GrD-GrE