Manufacturing method of electric wire with terminal, manufacturing method of wire harness

Abstract

A terminal-attached electric wire 10 comprises a terminal 1 and a coated conductive wire 11 which are electrically connected to each other. The terminal 1 includes a crimping portion 5 which is a part that crimps the coated conductive wire 11. The crimping portion 5 includes a conductive wire crimping portion 7 crimping a conductive wire 13 exposed from a coating portion 15 on a tip-end side of the coated conductive wire 11, and a coating crimping portion 9 crimping the coating portion 15 of the coated conductive wire 11. The coated conductive wire 11 includes a tensile strength body 17 disposed in substantially the center in a cross section, and a conductive wire 13 composed of a plurality of conductors disposed on an outer periphery of the tensile strength body 17. The tensile strength body 17 is composed of a plurality of strands. The conductive wire 13 is crimped along the circumference of the conductive wire 13 in the conductive wire crimping portion 7. Preferably, the tension strength of the tensile strength body 17 is greater than the tension strength of the conductive wire 13.

Description

[Technical field]

[0001] The present invention relates to an electric wire with a terminal for use in, for example, an automobile. Manufacturing method etc. [Background technology]

[0002] Typically, automotive wire harnesses are bundled together after crimp terminals are connected to the conductors of coated conductors, and are then wired as signal wires for automobiles, etc. In general, coated conductors and crimp terminals are connected by removing the coating from the tip of the coated conductor, crimping the exposed conductor with the conductor crimping part, and crimping the coating with the coating crimping part. In this process, an oxide film with poor conductivity is formed on the surface of the conductor, but this oxide film can be destroyed by strongly compressing the conductor crimping part when it is crimped. Therefore, the wires that make up the conductor come into contact with the conductor crimping part of the crimping terminal, and electrical conductivity is obtained between the crimping terminal and the conductor crimping part.

[0003] However, in wire harnesses used in automobiles in particular, thinner wires than before are sometimes used to reduce weight, and the wires are now as thin as 0.35sq (sq:mm 2 There is a demand for thin electric wires with a diameter of 0.1 mm or less (meaning 0.1 mm or less). In the case of thin electric wires, excessive compression can cause the wires to break or become damaged, resulting in a significant decrease in the tensile strength of the joint. However, if the compression is weakened, as mentioned above, the oxide film is not broken down sufficiently, resulting in an increase in the resistance of the joint.

[0004] That is, strong compression causes damage to the wires and reduces the strength of the crimped portion, while weak compression does not destroy the oxide film sufficiently, increasing the resistance of the crimped portion and causing the crimped portion to be pulled out due to insufficient crimping, making it difficult to ensure the strength of the crimped portion. Thus, it is difficult to control the balance between conductivity and tensile strength by the compression ratio alone, especially for thin-diameter coated electric wires. For this reason, a connector that makes it easy to control the balance between conductivity and tensile strength by the compression ratio with a single crimping is desired.

[0005] In response to this, electric wires containing tension members have been considered. For example, when using an electric wire made of a conductor with a tensile strength of about 30 N, in order to ensure a tensile strength exceeding 80 N required for electric wires for automobiles, an electric wire containing a tension member has been proposed in which a conductor wire is wound in a spiral shape around the outer periphery of a metallic or nonmetallic tension member. For such an electric wire, the conductor is stripped in stages to expose the tension member, which is then inserted into a sleeve, the tension member is crimped with a steel clamp, and the two are integrated with a curable resin such as an adhesive, and the conductor portion is crimped with an aluminum clamp or the like (Patent Document 1).

[0006] In addition, a coated electric wire has been proposed, which includes a conductor portion formed by bundling multiple strands together, and a fibrous tensile member disposed in the valleys between the strands on the outer periphery of the conductor portion and the inner periphery of the coating material (Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Utility Model Application Publication No. 61-046827 [Patent Document 2] JP 2012-3856 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in both Patent Document 1 and Patent Document 2, for example, when a thick-diameter covered conductor is used to connect to a crimp terminal, crimping can be performed at the conductor crimping portion with a compression ratio that satisfies both connection strength and connection resistance, but as the diameter of the electric wire becomes smaller, the range of appropriate crimping conditions for both connection strength and electrical resistance becomes narrower. This is because, as mentioned above, if an attempt is made to ensure connection strength, the conductor breaks and the connection resistance increases, and if emphasis is placed on connection resistance, connection strength cannot be obtained, which can cause the electric wire to come loose. Thus, the smaller the diameter of the electric wire, the more difficult it becomes to achieve both connection strength and electrical resistance.

[0009] Also, for example, in Patent Document 1, if the compression ratio during crimping is low (i.e., strong compression), the tensile strength of the tensile body is damaged and reduced, and if the compression ratio during crimping is high (i.e., low compression), the resistance of the crimped part increases. In particular, when crimping is performed in an open barrel shape, there is a problem that the conductor and the tensile body are scattered during crimping, the tensile strength is reduced, and the resistance of the crimped part increases. In addition, when connecting a conventional electric wire with a tensile body, a step stripping operation and a crimping process for crimping the tensile body and crimping the conductor are required. This results in a large number of parts, an increase in the number of work steps, and high costs. In particular, when the diameter of the electric wire becomes thin, the step stripping itself becomes difficult. Thus, in Patent Document 1, the manufacturing process becomes complicated, and the processing cost increases.

[0010] Also, Patent Document 2 discloses an example in which a fibrous tension member is provided between the conductor wires to improve strength without deteriorating electrical properties. However, when the electric wire of Patent Document 2 is crimped, the tension member enters between the conductor wire and the terminal, which may increase the resistance of the crimped portion. Even if the tension member is a conductor, when a temperature change is applied, a gap occurs between the tension member and the conductor wire due to the difference in thermal expansion coefficient, so the crimping resistance increases. Thus, Patent Document 2, like Patent Document 1, does not solve the problem that if the compression ratio during crimping is low, the tension member is damaged and the tensile strength decreases, and if the compression ratio during crimping is high, the crimped portion resistance increases.

[0011] The present invention has been made in view of the above problems, and provides an electric wire with a terminal that has good crimping workability and is capable of achieving both connection strength and connection resistance. Manufacturing method The purpose is to provide the following: [Means for solving the problem]

[0012] In order to achieve the above-mentioned object, the first invention is A method for manufacturing an electric wire with a terminal The electric wire with terminal is electrically connected to a coated conductor wire and a terminal. And,The coated conductor has a strength member and a conductor wire made of a plurality of conductors arranged around the periphery of the strength member, the conductor wire has a cross-sectional area of ​​0.35 sq. or less, the tensile strength of the strength member is higher than the tensile strength of the conductor wire, the terminal has a conductor crimping portion to which the conductor wire exposed from the coating at the tip of the coated conductor wire is crimped, and a coating crimping portion to which the coating of the coated conductor wire is crimped, and the conductor wire is crimped from the entire circumferential circumference of the conductor wire in the conductor crimping portion. In the electric wire with terminal, when the conductor crimping portion is crimped, in the initial stage of compression, both the compression ratio of the conductor and the apparent compression ratio of the tension member decrease, and as compression is continued thereafter, the decrease in the apparent compression ratio of the tension member becomes relatively small, and the decrease in the compression ratio of the conductor mainly progresses. A terminal-attached electric wire Manufacturing method It is.

[0013] The strength member may be made of a plurality of wires.

[0014] It is desirable that the compressibility of the conductor is equal to or less than the apparent compressibility of the region in which the strength member is disposed.

[0015] The conductive wire may be twisted around the outer periphery of the strength member.

[0016] At least the tip of the conducting wire may be compressed from the outer periphery.

[0017] The conductor may be subjected to a plating process.

[0018] It is preferable that the conductor wire is crimped at the conductor crimping portion from its entire circumference at a predetermined position in the axial direction.

[0019] It is desirable that the conductor crimping portion does not come into contact with the strength member.

[0020] The cross-sectional area of ​​the conductor may be 0.35 sq. or less.

[0021] According to the first invention, since the conductor is disposed on the outer periphery of the tensile member in a cross section perpendicular to the longitudinal direction of the covered conductor, when the conductor is crimped by the conductor crimping portion, the conductor and the conductor crimping portion can be reliably brought into contact with each other to ensure electrical continuity. Furthermore, since the conductor is crimped from the entire circumference in the conductor crimping portion, it is possible to suppress local stress (deformation) on the conductor during crimping and to ensure a sufficient contact area between the conductor and the conductor crimping portion. In addition, the coated conductor wire and the terminal can be easily crimped by the same process as that of the conventional electric wire with terminal. For example, the compression ratios of the tension member and the conductor wire decrease simultaneously at the beginning of compression, but the tension member reaches its compression limit first and the compression ratio is difficult to decrease any further, so that a difference in compression ratio between the tension member and the conductor wire is likely to occur. In such a crimping process that causes a difference in compression ratio, the tension member can maintain a high compression ratio while the compression ratio of the conductor wire can be reduced, which is particularly effective for conductor wires that require strong crimping to reduce the resistance of the crimped portion. Even if the compression ratios of the tension member and the conductor wire are equal in crimping, the tension member does not collapse excessively, so that a higher tensile strength can be achieved than in the conventional technology.

[0022] In addition, the tension member in the center ensures the tensile strength of the conductor. In this case, since there is no need to connect the tension member and the conductor with separate clamps as in the past, the number of parts can be reduced and the connection work is easy.

[0023] The above-mentioned effects are particularly effective when using a thin covered conductor wire having a cross-sectional area of ​​0.35 sq. or less, and even more effectively when using a thin covered conductor wire having a cross-sectional area of ​​0.3 sq. or less.

[0024] In addition, since the tensile strength of the tension member is higher than that of the conductor, deformation of the tension member is suppressed during compression, and the decrease in the tensile strength of the electric wire can be suppressed. In this case, if the tension member is made of multiple strands, the strands form irregularities on the outer periphery of the tension member during compression. Therefore, even if the conductor is deformed by the same amount, compared to when the outer periphery of a single tension member is deformed, part of the tension member can enter the irregularities while deforming, and therefore excessive crushing of the tension member can be suppressed.

[0025] In addition, since the tensile strength of the tension member is large when the conductor crimping portion is crimped, the compression ratio of the conductor can be set to be equal to or less than the apparent compression ratio of the region where the tension member is disposed, so that the conductor can be reliably compressed and deformed while suppressing deformation of the tension member.

[0026] Furthermore, if the conductor wires are twisted around the outer periphery of the tension member, the conductor wires can be prevented from becoming unraveled.

[0027] Similarly, by compressing the tip of the conductor from the outer periphery to form a terminal processing portion, it is possible to prevent the conductor from coming apart when the tip of the conductor is inserted into the tubular conductor crimping portion.

[0028] In addition, plating the surface of the conductor with a conductive metal is effective in improving conductivity and tensile strength, and also has the effect of improving workability by reducing the variation of the conductor strands during the crimping process.

[0029] Furthermore, by crimping the conductor from the entire circumference at a predetermined axial position of the conductor crimping portion, it is possible to more reliably prevent localized stress from occurring in the conductor during crimping and to ensure a sufficient contact area between the conductor and the conductor crimping portion.

[0030] In addition, by crimping the conductor crimping portion so as not to come into contact with the tension member, it is possible to suppress the disorder of the conductor arrangement, ensure that the conductor and the conductor crimping portion come into contact with each other, and ensure that the conductor and the tension member are compressed. For example, if the open barrel shape is used for crimping such that the barrel pieces strongly bite into the center of the cross section, the cross-sectional shape of the wire changes significantly, and the compression ratio of both the conductor and the tension member does not decrease, making it difficult to ensure the desired performance. In addition, by preventing the conductor crimping portion from coming into contact with the tension member, it is possible to suppress damage to the tension member at the conductor crimping portion.

[0031] The second invention is the electric wire with terminal according to the first invention. Manufactured by the manufacturing method Wires with multiple terminals of integration do A wire harness characterized by Manufacturing method It is.

[0032] According to the second aspect of the present invention, a wire harness in which a plurality of small diameter electric wires are bundled can be obtained. Effect of the Invention

[0035] According to the present invention, there is provided an electric wire with a terminal which has good crimping workability and can achieve both connection strength and connection resistance. Manufacturing method etc. can be provided. [Brief description of the drawings]

[0036] [Figure 1] FIG. 2 is a perspective view showing a terminal-fitted electric wire 10. [Figure 2A] FIG. 2 is an axial cross-sectional view showing the electric wire with terminal 10. [Figure 2B] FIG. 4 is a radial cross-sectional view of the conductor crimping portion 7. [Diagram 3] A diagram showing the terminal 1 and the coated conductor wire 11 before crimping. [Figure 4A] FIG. [Figure 4B] FIG. 4 is a diagram showing the configuration of the terminal processing portion 19. [Figure 4C] FIG. 4 is a diagram showing the configuration of an end processing unit 19. [Figure 4D] FIG. 4 is a diagram showing the configuration of an end processing unit 19. [Diagram 5] 11A and 11B are diagrams showing another embodiment of the terminal processing unit 19. [Figure 6A] 5 is a schematic diagram showing changes in a conductor crimping portion 7 during a crimping process. FIG. [Figure 6B] 5 is a schematic diagram showing changes in a conductor crimping portion 7 during a crimping process. FIG. [Figure 6C] 5 is a schematic diagram showing changes in a conductor crimping portion 7 during a crimping process. FIG. [Figure 7] FIG. 4 is a schematic diagram showing the conductor crimping portion 7 after crimping. [Figure 8] FIG. 2 is a diagram showing a terminal 1a and a coated conductor wire 11 before crimping. [Figure 9A] FIG. [Figure 9B] Cross-sectional view taken along line AA in FIG. 9A. [Figure 9C] Cross-sectional view of line BB in Figure 9A. [Figure 10A] 13 is another radial cross-sectional view of the conductor crimping portion 7. FIG. [Figure 10B] 13 is another radial cross-sectional view of the conductor crimping portion 7. FIG. [Figure 10C] 13 is another radial cross-sectional view of the conductor crimping portion 7. FIG. [Figure 11A]FIG. 4 is a cross-sectional view of another coated conductor wire 11. [Figure 11B] FIG. 4 is a cross-sectional view of another coated conductor wire 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing an electric wire with terminal 10, Fig. 2A is an axial cross-sectional view of the electric wire with terminal 10, and Fig. 2B is a radial cross-sectional view of a conductor crimping portion 7. The electric wire with terminal 10 is configured by electrically connecting a terminal 1 and a covered conductor wire 11.

[0038] The coated conductor wire 11 is composed of a conductor wire 13 made of, for example, copper, a copper alloy, aluminum, or an aluminum alloy, and a coating portion 15 that coats the conductor wire 13. That is, the coated conductor wire 11 includes the coating portion 15 and the conductor wire 13 exposed from its tip.

[0039] The terminal 1 is made of, for example, copper, a copper alloy, aluminum, or an aluminum alloy. A covered conductor wire 11 is connected to the terminal 1. The terminal 1 is configured by connecting a terminal body 3 and a crimping portion 5 via a transition portion 4.

[0040] The terminal body 3 is a plate material of a predetermined shape formed into a cylinder with a rectangular cross section. The terminal body 3 has an elastic contact piece formed by folding the plate material into the rectangular cylinder inside. The terminal body 3 is connected by inserting a male terminal or the like from the front end. In the following description, an example is shown in which the terminal body 3 is a female terminal that allows the insertion of an insertion tab (not shown) of a male terminal or the like, but the detailed shape of the terminal body 3 is not particularly limited in the present invention. For example, an insertion tab of a male terminal may be provided instead of the female terminal body 3, or a bolt fastening portion like a round terminal may be provided.

[0041] The crimping portion 5 of the terminal 1 is a portion that is crimped to the coated conductor wire 11, and includes a conductor crimping portion 7 that crimps the conductor wire 13 exposed from the coating portion 15 at the tip side of the coated conductor wire 11, and a coating crimping portion 9 that crimps the coating portion 15 of the coated conductor wire 11. That is, the conductor wire 13 exposed when the coating portion 15 is peeled off is crimped by the conductor crimping portion 7, and the conductor wire 13 and the terminal 1 are electrically connected. Also, the coating portion 15 of the coated conductor wire 11 is crimped by the coating crimping portion 9 of the terminal 1. In this embodiment, the conductor crimping portion 7 and the coating crimping portion 9 are each configured to have a tubular shape (approximately cylindrical shape) that is closed in the circumferential direction.

[0042] Serrations (not shown) may be provided in the width direction (direction perpendicular to the longitudinal direction) on a part of the inner surface of the conductor crimping portion 7. By forming the serrations in this manner, the oxide film on the surface of the conductor 13 can be easily destroyed when the conductor 13 is crimped, and the contact area with the conductor 13 can be increased.

[0043] As shown in FIG. 2B, the coated conductor wire 11 has a tension member 17 disposed at approximately the center of the cross section, and a conductor wire 13 consisting of a plurality of conductors disposed around the periphery of the tension member 17. The tension member 17 is a member that receives tension in response to a tensile load. The tension member 17 is composed of a plurality of strands, which will be described in detail later. In addition, the conductor wire 13 may be twisted in a spiral shape in the longitudinal direction of the coated conductor wire 11 at the outer periphery of the tension member 17. In this case, each of the conductor wires 13 (strands) disposed around the periphery of the tension member 17 may be a conductor wire 13 (strand) having the same cross-sectional area and the same shape. The conductor wire 13 may be, for example, a soft copper wire, a hard copper wire, a copper alloy wire, an aluminum wire, an aluminum alloy wire, or the like, but a soft copper wire is preferable from the viewpoint of electrical wire conductivity.

[0044] As described above, the conductor crimping portion 7 is tubular. Therefore, at a predetermined position in the axial direction of the conductor crimping portion 7 (cross section at a predetermined position), the conductor 13 can be crimped from its entire circumference of 360° by the conductor crimping portion 7. That is, the conductor 13 is crimped from the entire circumference in the circumferential direction of the conductor 13 by the conductor crimping portion 7. Therefore, the inner surface of the conductor crimping portion 7 comes into contact with the conductor 13 over the entire circumference, and it is possible to suppress local stress (deformation) occurring in the conductor 13 during crimping.

[0045] Here, the present invention is particularly effective when the cross-sectional area of ​​the conductor 13 (total cross-sectional area of ​​the wires) is 0.35 sq or less. That is, the terminal 1 is capable of crimping the conductor 13 having a cross-sectional area of ​​0.35 sq or less. Furthermore, the cross-sectional area of ​​the conductor 13 (total cross-sectional area of ​​the wires) is preferably 0.3 sq or less, and in this case, the terminal 1 is preferably capable of crimping the conductor 13 having a cross-sectional area of ​​0.3 sq or less. Furthermore, since the conductor 13 is used together with the tensile member 17, the cross-sectional area of ​​the conductor 13 may be 0.05 sq or less. The smaller the cross-sectional area of ​​the conductor 13, the greater the effect of this embodiment. From the viewpoint of ensuring the crimping strength, the cross-sectional area of ​​the conductor 13 is preferably 0.01 sq or more, and more preferably 0.03 sq or more.

[0046] The tension member 17 may be a metal wire such as a steel wire, or may be made of resin or fiber-reinforced resin, but is made of a bundle of multiple strands. For example, the strands constituting the tension member 17 may be made of PBO (polyparaphenylene benzobisoxazole) fiber, aramid fiber, carbon steel wire, stainless steel wire, liquid crystal polyester fiber, glass fiber, or carbon fiber, but nonmetallic wires are preferable in terms of corrosion resistance.

[0047] Furthermore, it is desirable that the tensile strength of the tension member 17 is higher than that of the conductor 13. Note that, although tensile strength refers to the maximum stress that leads to breakage when subjected to tensile stress, in this embodiment, it is taken as a relative index of the ease of breakage due to crushing of the material during crimping. In other words, the tension member 17 is made of a material that is less likely to deform during crimping compared to the conductor 13. Note that, further, it is desirable that the Young's modulus of the tension member 17 is higher than that of the conductor 13, and the yield stress (or proof stress) of the tension member 17 is higher than the yield stress (or proof stress) of the conductor 13.

[0048] Next, a method for manufacturing the electric wire with terminal 10 will be described. FIG. 3 is a perspective view showing the terminal 1 and the covered conductor wire 11 before crimping. As described above, the terminal 1 has the terminal body 3 and the crimping portion 5. The crimping portion 5 is configured to have a substantially cylindrical shape with the conductor crimping portion 7 and the covering crimping portion 9 integrated together. The crimping portion 5 may be formed, for example, by rolling a plate member, butting the ends together, and joining them in the longitudinal direction by welding or brazing, or the terminal 1 may be formed by expanding a tubular member. The conductor crimping portion 7 and the covering crimping portion 9 may have the same diameter, or, as shown in the figure, the inner diameter of the covering crimping portion 9 may be larger than the inner diameter of the conductor crimping portion 7.

[0049] First, as described above, the coating 15 at the tip of the coated conductor wire 11 is stripped to expose the conductor wire 13 at the tip. Next, as shown in Fig. 4A, a terminal processing section 19 may be formed at the tip of the conductor wire 13 before it is inserted into the crimping section 5 of the terminal 1. The terminal processing section 19 is a processing section that integrates the individual wires of the conductor wire 13 so that they do not come apart.

[0050] As described above, the tensile member 17 is disposed substantially in the center, and the conductor 13 is disposed on its outer periphery. The conductor 13 is made of a plurality of conductors. In such a case, as shown in Fig. 4B, at least the tip of the conductor 13 can be compressed from the outer periphery to form the end processing portion 19. In this way, by compressing the tip of the conductor 13 from the outer periphery, the wire is prevented from coming apart, and it is easy to insert the wire into the tubular crimping portion 5.

[0051] 4C, at least the tip of the conductor 13 may be plated all at once to form the end processing portion 19 with the plating layer 21. By plating the tip of the conductor 13 all at once from the outer periphery in this manner, the wire is prevented from coming apart, and it is easy to insert the wire into the tubular crimping portion 5.

[0052] Depending on the plating method, high temperatures may be generated when plating is performed all at once from the outer periphery of the conductor 13. If plating is performed all at once after twisting the conductor 13 using such a plating method, the tensile member 17 may be deteriorated by the heat, resulting in a decrease in tensile strength.

[0053] In such a case, as shown in FIG. 4D, a plating layer 21 may be formed for each conductor and then twisted around the outer periphery of the tension member 17. Alternatively, as shown in FIG. 5, a plating layer 21 may be formed for each conductor and furthermore, a plating process may be performed on the tip portions of the plurality of conductors from the outer periphery all at once. In this case, the type of plating for each conductor and the type of plating performed all at once may be different. As described above, by performing plating all at once, it is possible to prevent the conductors from coming apart, but when the conductors are bundled and plated all at once, there is a risk that the plating may become thick or thin in some areas due to the influence of the conductor shape, etc. In contrast, by performing a base plating process for each conductor in advance, this influence can be reduced and approximately uniform plating can be achieved all at once.

[0054] The terminal processing section 19 is not limited to the method using compression or plating, and may be, for example, soldering or welding the tip of the conductor wire 13 to suppress the stranding of the wire. Also, a combination of multiple terminal processing methods, such as compression from the periphery and collective plating, may be used.

[0055] Next, the coated conductor wire 11 whose tip has been treated in this manner is inserted from the rear end side of the tubular crimping portion 5 of the terminal 1. When the tip of the coated conductor wire 11 is inserted into the crimping portion 5, the exposed portion of the conductor wire 13 is located inside the conductor crimping portion 7, and the coating portion 15 is located inside the coating crimping portion 9. At this time, the tip of the conductor wire 13 may protrude from the tip of the conductor crimping portion 7.

[0056] The diagram in the center of Fig. 6A is a schematic cross-sectional view of the conductor crimping portion 7 before crimping, the diagram on the left is a diagram showing the shape of the region of the strength member 17, and the diagram on the right is an enlarged view of the region of the strength member 17. As described above, the strength member 17 is formed by bundling a plurality of strength member wires 17a. The conductor wire 13 is disposed on the outer periphery of the strength member wires 17a.

[0057] The cross-sectional area of ​​the conductor 13 before crimping is the sum of the cross-sectional areas of all the conductors. In other words, it is the product specification of the coated conductor 11, and the total cross-sectional area can be calculated relatively easily even by image analysis of the cross section. On the other hand, the strength member wires 17a are finer than the conductors constituting the conductor 13, and it is difficult to clearly distinguish the strength member wires 17a from the gaps between the strength member wires 17a. For this reason, the cross-sectional area of ​​the strength member 17 before crimping is the area of ​​the region of the strength member surrounded by the conductor 13 (A in FIG. 6A).

[0058] Fig. 6B is a view corresponding to Fig. 6A during compression. When compression starts, deformation of the conductor 13 and deformation of the strength member wires 17a progress. At this time, even if the total cross-sectional area of ​​the strength member wires 17a does not change significantly in the early stage of deformation, the gaps between the strength member wires 17a decrease, and the cross-sectional area of ​​the apparent strength member 17 region (A1 in Fig. 6B) decreases. That is, when the conductor crimping portion 7 is crimped, both the compression ratio due to the deformation of the conductor 13 and the apparent compression ratio of the strength member 17 decrease in the early stage of compression.

[0059] Fig. 6C is a diagram corresponding to Fig. 6A in a state where crimping has been completely completed. As described above, the strength of the tension body wire 17a is high and difficult to deform compared to the conductor wire 13, so that after the gap is reduced, the cross-sectional area of ​​the tension body 17 (A2 in Fig. 6C) does not decrease significantly, and mainly the deformation (reduction in cross-sectional area) of the conductor wire 13 progresses. Note that the apparent cross-sectional area of ​​the tension body 17 after compression is the cross-sectional area inside the conductor wire crimping portion 7 minus the cross-sectional area of ​​the conductor wire 13. In this way, by continuing compression from the state of Fig. 6B, the decrease in the apparent compression ratio of the tension body 17 becomes relatively small, and mainly the decrease in the compression ratio of the conductor wire 13 progresses.

[0060] Here, the compression ratio of the conductor 13 after crimping is equal to or less than the apparent compression ratio of the region where the tension member 17 is disposed. If the total cross-sectional area of ​​the conductor 13 before the crimping process is A0 (FIG. 6A) and the total cross-sectional area of ​​the conductor 13 after compression is A3 (FIG. 6C), then the compression ratio of the conductor 13 = A3 / A0 (%). If the cross-sectional area of ​​the tension member region before the crimping process is A (FIG. 6A) and the cross-sectional area of ​​the tension member region after compression is A2 (FIG. 6C), then the apparent compression ratio of the region where the tension member 17 is disposed = A2 / A (%). Therefore, A3 / A0≦A2 / A. The area ratio A3 / A2 of the conductor 13 and the tension member 17 after compression varies depending on the compression ratio of the entire electric wire.

[0061] As described above, the conductor 13 is crimped at the conductor crimping portion 7 from the entire circumference of the conductor 13 in the circumferential direction. As shown in FIG. 6C, the strength body 17 is formed by a plurality of strength body wires 17a, so that unevenness is formed on the outer periphery of the strength body 17 (region). Therefore, at the interface between the strength body 17 and the conductor 13, the conductor 13 deforms in response to the unevenness caused by the strength body wires 17a. The uneven outer shape of the strength body 17 increases the contact area between the conductor 13 and the strength body 17, and increases the frictional force. Therefore, force is easily transmitted from the conductor 13 to the strength body 17 when tension is applied, and an increase in strength can be expected when tension is applied to the conductor 13.

[0062] For example, if the strength member 17 is a solid wire, the interface between the strength member 17 and the conductor 13 is almost smooth. At this time, the strength member 17 is difficult to deform relative to the conductor 13, so the conductor 13 deforms by being crushed along the surface of the strength member 17. This may cause the conductor 13 to become too thin and break. In contrast, if the outer peripheral surface of the strength member 17 is uneven, the conductor 13 can deform to fit into the unevenness, so it is not crushed excessively and breakage can be suppressed.

[0063] In addition, the tensile body 17 (tensile body wire 17a) is less likely to break due to a reduction in cross-sectional area because it is less deformed than the conductor 13. In particular, since the conductor crimping portion 7 is tubular, the conductor 13 is compressed from the entire circumference, and the conductor 13 is disposed between the tensile body 17 and the conductor crimping portion 7, and the tensile body 17 and the conductor crimping portion 7 do not come into contact with each other, so that the tensile body 17 is not damaged.

[0064] 7, there are cases where the tension body 17 (tension body wire 17a) gets between the conductor wires 13, and a part of the tension body 17 comes into contact with the conductor crimping portion 7 (part C in the figure). As described above, it is preferable that the tension body 17 and the conductor crimping portion 7 do not come into contact with each other, but as shown in the figure, a part of the tension body 17 may come into slight contact with the conductor crimping portion 7. For example, in any cross section, if the circumferential length of the tension body 17 that is in contact with the conductor crimping portion 7 is 30% or less of the total circumferential length of the tension body 17, the effect of suppressing damage to the tension body 17 can be obtained.

[0065] In this manner, it is possible to obtain the electric wire with terminal 10. Furthermore, it is possible to obtain a wiring harness in which a plurality of electric wires with terminals, including the obtained electric wire with terminal 10, are integrated together.

[0066] As described above, according to this embodiment, the conductor 13 is crimped from all directions of 360° around the conductor 13 in the conductor crimping section 7, so that it is possible to suppress local stress (deformation) from occurring in the conductor 13 during crimping. Furthermore, it is possible to crimp the conductor 13 without significantly destroying the structure of the central tensile member 17 and the conductor 13 twisted around it during crimping. Furthermore, since the conductor crimping section 7 comes into contact with the conductor 13 all around, it is also possible to suppress deterioration of resistance.

[0067] In addition, since the tensile strength of the tension member 17 is higher than that of the conductor 13, stronger crimping can be performed. In other words, even if strong crimping is performed, the tension member 17 is not damaged, so that the covered conductor 11 can be prevented from breaking at the conductor crimping portion 7. In addition, by performing strong crimping, the oxide film of the conductor 13 can be destroyed and the conductor 13 and the terminal 1 can be more reliably attached to each other, so that both low resistance and high tensile strength of the crimping portion can be achieved. For this reason, it is particularly effective for thin electric wires of 0.35 sq or less.

[0068] In addition, since the tensile body 17 is made of the tensile body wires 17a, in the initial stage of crimping, the conductor wire 13 is deformed and the gaps between the tensile body wires 17a are eliminated. Therefore, a compressive force is not applied only to the conductor wire 13, and the conductor wire 13 can be subjected to a moderate degree of compressive deformation. In addition, the outer peripheral surface of the tensile body 17 is uneven, and the conductor wire 13 is deformed to follow the uneven shape, so that excessive crushing of the conductor wire 13 is suppressed.

[0069] In the conductor crimping section 7, the terminal 1 (conductor crimping section 7) is crimped to the internal conductor 13, and the conductor 13 is crimped to the internal tensile body 17 (tensile body wire 17a). At this time, if the conductor crimping section 7 has a sufficient compression amount, the frictional force between the terminal 1 (conductor crimping section 7) and the conductor 13 and the frictional force between the conductor 13 and the tensile body 17 (tensile body wire 17a) are sufficient, so that a high pull-out force can be obtained. On the other hand, if the compression amount is insufficient, the frictional force between the terminal 1 (conductor crimping section 7) and the conductor 13 can be relatively easily ensured, but the frictional force between the conductor 13 and the tensile body 17 (tensile body wire 17a) cannot be sufficiently ensured, so that a high pull-out force cannot be obtained. Therefore, in the conductor crimping section 7, it is desirable to ensure a sufficiently large compression amount (low compression ratio) within a range in which the conductor 13 does not break.

[0070] Furthermore, when the conductor crimping portion 7 is cylindrical as in this embodiment and there is a brazed portion at the joint, the brazed portion with low hardness exerts less compressive stress on the conductor 13, making it easier to pull out the tensile member 17. For this reason, it is preferable to remove the brazed portion or to eliminate the brazed portion and make the hardness of the joint formed at the conductor crimping portion 7 equal to the hardness of the material in the conductor crimping portion 7.

[0071] Second embodiment Next, a second embodiment will be described. Fig. 8 is a perspective view of a terminal 1a according to the second embodiment before a coated conductor wire 11 is crimped. In the following description, the same reference numerals as in Figs. 1 to 6C are used for configurations that have the same functions as in the first embodiment, and duplicated description will be omitted.

[0072] The terminal 1a has a configuration substantially similar to that of the terminal 1, but differs in that the crimping portion 5 has an open barrel shape. The terminal 1a can be crimped in the same manner as the terminal 1. Fig. 9A is a plan view showing a terminal-attached electric wire 10a in which the terminal 1a and the coated conductor wire 11 are crimped.

[0073] Here, in the open barrel type conductor crimping portion 7, at least a pair of opposing barrel pieces are folded to crimp the conductor 13. In this case, in this embodiment, the opposing barrel pieces are arranged in a staggered manner, shifted from each other in the axial direction of the conductor crimping portion 7. Note that in the insulation crimping portion 9, the opposing barrel pieces may be butted against each other, or, similarly to the conductor crimping portion 7, the barrel pieces may be arranged shifted from each other in the axial direction.

[0074] In this way, an open barrel type crimping section having barrel pieces arranged in a staggered pattern is generally capable of crimping the barrel pieces and the object to be crimped in close contact with each other without damaging the object to be crimped.

[0075] In addition, when the barrel pieces are arranged in a staggered pattern, there are cases where the entire outer circumference of the conductor wire 13 cannot be completely crimped. Fig. 9B is a cross-sectional view taken along line AA in Fig. 9A, and Fig. 9C is a cross-sectional view taken along line BB in Fig. 9A. As shown in Figs. 9B and 9C, in a cross-section at a predetermined position in the axial direction of the conductor wire crimping portion 7, a gap 23 that is not crimped by the conductor wire crimping portion 7 is formed in a part of the circumferential direction.

[0076] However, even in this case, the gaps 23 are not arranged linearly in the axial direction of the conductor crimping portion 7, but are formed at different circumferential positions in each cross-sectional position. For this reason, it can be said that the entire circumferential circumference of the conductor 13 is always crimped at any position in the axial direction of the conductor crimping portion 7. For example, the circumferential position of the gap 23 in FIG. 9B is crimped by the conductor crimping portion 7 at the cross-sectional position in FIG. 9C, and the circumferential position of the gap 23 in FIG. 9C is crimped by the conductor crimping portion 7 at the cross-sectional position in FIG. 9B. In this way, the entire circumferential circumference of the conductor 13 may be crimped at any position of the conductor crimping portion 7.

[0077] In this way, even if the crimping portion 5 of the conductor crimping portion 7 is of the open barrel type, the same effects as those of the first embodiment and the like can be obtained. Furthermore, by making the crimping portion 5 of the open barrel type, it is easy to arrange the conductor 13 in the crimping portion 5.

[0078] As described above, as long as the conductor 13 is compressed from the entire circumference in the conductor crimping portion 7, the conductor crimping portion 7 does not necessarily have to be tubular. Also, even in the case of an open barrel type conductor crimping portion 7, the barrel pieces may be arranged at the same position facing each other in the axial direction of the conductor crimping portion 7 instead of being staggered.

[0079] For example, Fig. 10A is a cross-sectional view showing an example of crimping using an open barrel type conductor crimping unit 7 in which barrel pieces are arranged at opposing positions. In the example shown in Fig. 10A, the barrel pieces are arranged at opposing positions at the same position in the axial direction of the conductor crimping unit 7, and are crimped so that the barrel pieces overlap each other. In other words, the opposing barrel pieces are overlapped with each other, and crimped so that one barrel piece wraps around the other barrel piece.

[0080] Also, as shown in Fig. 10B, the tips of the barrel pieces arranged at positions opposite to each other may be butted against each other. In this case, as shown in Fig. 10C, if the tips of the barrel pieces bite into the inside and come into contact with the tension members 17, the arrangement of the conductor 13 may be disturbed, and the tension members 17 may break, which is not desirable. In this way, even with an open barrel type conductor crimping portion, the conductor 13 can be crimped from all around, but it is desirable that the barrel pieces do not bite into the tension members 17 until they come into contact with them. EXAMPLES

[0081] Various types of electric wires with terminals were prepared, and the electrical properties (resistance performance of the crimped part), mechanical properties (tensile strength performance), and corrosion prevention properties of the crimped part were evaluated. All of the coated conductors used had a tensile member placed in the center of the cross section and a conductor twisted around the outer periphery. The electrical properties were evaluated by measuring the electrical resistance between the terminal and the coated conductor. The mechanical properties were evaluated by pulling the coated conductor from the terminal, and measuring the tensile strength based on the load applied when the coated conductor was pulled out. The corrosion prevention properties were evaluated by a salt spray test. The materials used are shown in Table 1, and the conditions and evaluation results are shown in Tables 2 to 10.

[0082]

Table 1

[0083]

Table 2

[0084]

Table 3

[0085]

Table 4

[0086]

Table 5

[0087]

Table 6

[0088]

Table 7

[0089]

Table 8

[0090]

Table 9

[0091]

Table 10

[0092] The cross-sectional area of ​​an electric wire is the total cross-sectional area of ​​the conductor. Conductor material is the material that makes up the conductor, and strength members are the materials that make up the strength members. In addition, "fiber" in the case of strength members indicates that the members are formed by bundling multiple thin wires (fibers), and "solid wire" indicates that the members are one thick strength member.

[0093] Conductor processing is the processing of the ends of conductors. "Tin plating" is the application of tin plating to individual conductors as shown in Figure 4C, while "mass plating" is the application of tin plating to the entire conductor as a whole as shown in Figure 4B.

[0094] The terminal shape "tube" is a tubular shape similar to terminal 1 shown in Fig. 1. Also, "open barrel wrap" is the shape shown in Fig. 10A, "open barrel staggered" is the shape shown in Fig. 9A, "open barrel (no bite)" is the shape shown in Fig. 10B, and "open barrel (with bite)" is the shape shown in Fig. 10C.

[0095] The conductor compression ratio is the total cross-sectional area of ​​the conductor after compression relative to the total cross-sectional area of ​​the conductor before compression at the conductor crimping portion. Also, the strength member compression ratio is the apparent compression ratio of the strength member region, which is the cross-sectional area of ​​the region surrounded by the conductor after compression relative to the cross-sectional area of ​​the region surrounded by the conductor before compression at the conductor crimping portion.

[0096] The crimped part resistance is the electrical resistance between the tip of the terminal and the rear end of the 100 mm long coated conductor. A crimped part resistance of less than 1 mΩ was rated as "excellent", 1 mΩ to 2 mΩ was rated as "good", and over 2 mΩ was rated as "bad". The tensile strength is the load when the coated conductor is pulled out from the terminal. For the tensile strength performance, 50 N or more was rated as "excellent", 40 N or more but less than 50 N was rated as "good", and less than 40 N was rated as "bad". In addition, for the corrosion prevention performance, salt water with a temperature of 35°C and a salt water concentration of 5 mass% was sprayed at 68.6 to 176.5 kPa for 96 hours, and then left at a temperature of 80°C and a humidity of 90 to 95% for 96 hours. After drying at room temperature, it was checked whether electricity could be passed through it, and those that could be passed through it were rated as "excellent".

[0097] As can be seen from Tables 2 to 8, in the cases where the tensile strength of the reinforcing member was higher than that of the conductor wire and the reinforcing member was composed of multiple wires, the crimped portion resistance performance and tensile strength performance were "good" or better for all wire cross-sectional areas from 0.05 sq. to 0.35 sq. In particular, in the cases where the conductor wire was not Corson alloy wire, the crimped portion resistance performance was all "excellent." In addition, in the cases where the reinforcing member was made of resin fiber other than carbon fiber, the tensile strength performance was all "excellent."

[0098] On the other hand, in Comparative Examples 1 and 3, since the conductor did not have a tensile member and was crimped moderately to strongly, the conductor broke during crimping, and the tensile strength performance was "bad." In contrast, in Comparative Example 2, the conductor was crimped weakly, and the tensile strength performance was "excellent," but the oxide film on the surface of the conductor was not sufficiently destroyed, and the resistance performance of the crimped portion was "bad."

[0099] In Comparative Examples 4 and 5, the tensile member was a single wire and the outer surface was hardly deformed, so the conductor was crushed too much during crimping and broke, resulting in a crimped part resistance performance of "bad". On the other hand, in Comparative Example 6, the crimping was weaker than in Comparative Examples 4 and 5, suppressing the crushing of the conductor and resulting in a crimped part resistance performance of "good", but the crimping was insufficient, resulting in a tensile strength performance of "bad". Similarly, in Comparative Example 7, the tensile member was a single wire and the outer surface was hardly deformed, so the crimped part resistance performance was "bad" and the corrosion resistance was "bad" due to electrolytic corrosion caused by contact between dissimilar metals, the copper wire and the stainless steel wire.

[0100] In Comparative Example 8, the tension member was made of resin fiber, but the tensile strength of the tension member was lower than that of the conductor material, so the tension member was crushed during crimping, resulting in a "bad" tensile strength performance. In Comparative Example 9, the barrel piece in the conductor crimped portion cut into the tension member, causing the arrangement of the conductors to become disorganized, resulting in a "bad" crimped portion resistance performance, and the tension member was damaged, resulting in a "bad" tensile strength performance.

[0101] Although the embodiment of the present invention has been described above with reference to the attached drawings, the technical scope of the present invention is not limited to the above-described embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0102] For example, in the above description, an example in which the conductor 13 is arranged in one layer around the tensile member 17 has been shown, but the arrangement of the conductor 13 is not limited to this. As long as the conductor 13 is arranged on the outer periphery of the tensile member 17, the conductor 13 may be arranged in two layers around the tensile member 17 as shown in FIG. 11A, or may be arranged in three layers around the tensile member 17 as shown in FIG. 11B. In addition, the number of the conductors 13 in the layer in contact with the tensile member 17 may be three or more, and preferably 20 or less, from the viewpoint of the conductivity and strength of the conductor 13 itself. For example, the number of the conductors 13 may be 12 or 14, or may be 6 or 8, as shown in FIG. 4B to FIG. 4D, FIG. 5, FIG. 11A, FIG. 11B, etc.

[0103] In the above description, the tensile body 17 is composed of a plurality of tensile body wires 17a. However, even if the tensile body 17 is a solid wire, it may be a solid wire as long as the external shape can be deformed together with the conductor 13 during compression and an uneven shape is formed on the outer periphery after compression. For example, the above-mentioned Comparative Examples 4 to 7 were rejected because the tensile body was a solid wire, but even if it is a single wire, it is possible to suppress the decrease in the resistance performance of the crimped portion as long as the outer surface is slightly deformed during compression of the conductor. However, if the tensile body 17 is more easily deformed than the conductor 13, it will not function as the tensile body 17. Therefore, it is preferable that the conductor 13 is preferentially crushed during compression, and when the tensile body extends in the axial direction, the pressure from the conductor 13 forms slight unevenness on the surface of the tensile body. [Explanation of symbols]

[0104] 1, 1a………Terminal 3: Terminal body 4. Transition section 5……… Crimping section 7………Conductor crimping section 9……Sheathing crimping part 10, 10a.....Terminal wire 11....Coated conductor 13……Conducting wire 15....Coating part 17……Tensile strength body 17a……Tensile strength body wire 19... Terminal processing section 21: Plating layer 23...Gap

Claims

1. A method for producing an electric wire with a terminal, comprising the steps of: The terminal-attached electric wire is The coated conductor wire and the terminal are electrically connected to each other, The coated conductor wire includes a tension member and a conductor wire that is arranged around the tension member and is made of a plurality of conductors, The cross-sectional area of ​​the conductor is 0.35 sq. or less, the tensile strength of the tension member is higher than the tensile strength of the conductor; The terminal includes a conductor crimping portion to which the conductor exposed from the coating portion at the tip of the coated conductor is crimped, and a coating crimping portion to which the coating portion of the coated conductor is crimped, The conductor is crimped from an entire circumference of the conductor in a circumferential direction at the conductor crimping portion, a compressible portion that compresses the conductor crimping portion of the electric wire and the conductor crimping portion of the electric wire, the compressible portion being compressed in a direction perpendicular to the conductor crimping portion, and the compressible portion being compressed in a direction perpendicular to the conductor crimping portion of the electric wire.

2. 2. The method for manufacturing an electric wire with a terminal according to claim 1, wherein the tension member is made of a plurality of strands.

3. 3. The method for manufacturing an electric wire with a terminal according to claim 1, wherein a compressibility of the conductor is equal to or less than an apparent compressibility of a region where the tension member is disposed.

4. 4. The method for manufacturing an electric wire with terminal according to claim 1, wherein the conductor wire is twisted around an outer periphery of the tension member.

5. 5. The method for producing an electric wire with terminal according to claim 1, wherein at least a tip portion of the conductor is compressed from an outer periphery side.

6. The method for producing an electric wire with a terminal according to any one of claims 1 to 5, wherein the conductor is plated.

7. 7. The method for manufacturing an electric wire with a terminal according to claim 1, wherein the conductor is crimped at the conductor crimping portion from an entire circumference at a predetermined position in an axial direction.

8. The method for manufacturing an electric wire with a terminal according to any one of claims 1 to 7, wherein the conductor crimping portion does not contact the tension member.

9. The method for producing an electric wire with a terminal according to any one of claims 1 to 8, characterized in that the conductor wire has a cross-sectional area of ​​0.3 sq. or less.

10. A method for producing a wire harness, comprising integrating a plurality of electric wires with terminals produced by the method for producing an electric wire with terminal according to any one of claims 1 to 9.

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