Electrical wire with terminal

Abstract

An electric wire with a terminal according to one embodiment of the present disclosure is an insulated wire with a terminal, which comprises: a plurality of insulated wires in each of which a conductor is exposed from an insulating layer; a terminal that is electrically connected to the conductor; and a heat shrinkable tube that is disposed on the terminal and covers a connection part of the terminal. The terminal has: a counterpart-side connection part which is electrically connected to a connection destination of the counterpart; an electric wire fixation part to which the insulated wires are fixed; and a conductor connection part which is continuous between the counterpart-side connection part and the electric wire fixation part and to which the conductor is connected. The conductor connection part and the electric wire fixation part are provided with one or a plurality of through holes. The heat shrinkable tube at least covers the through holes. The hollow inside the heat shrinkable tube is filled with an adhesive that is mainly composed of a thermoplastic resin.

Description

Wire with terminal

[0001] This application claims priority to Japanese Patent Application No. 2024-109208, filed on July 5, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] 2. Description of the Related Art In insulated wires mounted on vehicles such as automobiles, conductors exposed at the ends of a plurality of insulated wires may be connected to terminals.

[0003] Such electric wires are classified as electric wires with terminals, and some of them have a waterproof structure that prevents liquid from entering the connection between the conductor and the terminal to prevent electrical defects. Specifically, a waterproof member such as a heat-shrinkable tube is attached to surround the connection between the conductor and the terminal. For example, a conventional technique discloses a technique in which an adhesive is applied to the connection between the terminal of the electric wire with terminal and the conductor of the insulated electric wire, and the heat-shrinkable tube that covers the connection is heated before shrinking, causing the heat-shrinkable tube to shrink and waterproof the connection between the terminal and the conductor (see Patent Document 1).

[0004] JP 2012-94340 A

[0005] A terminal-attached electric wire according to one aspect of the present disclosure includes a plurality of insulated electric wires, each having a conductor exposed from an insulating layer, a terminal electrically connected to the conductor, and a heat-shrinkable tube disposed on the terminal and covering the connection portion of the terminal, wherein the terminal has a mating connection portion electrically connected to a mating connection destination, a wire fixing portion to which the plurality of insulated electric wires are fixed, and a conductor connection portion provided between the mating connection portion and the wire fixing portion and to which the conductor is connected, wherein one or more through holes are provided in the conductor connection portion and the wire fixing portion, the heat-shrinkable tube covers the through holes, and an adhesive containing a thermoplastic resin as a main component is filled into the gap inside the heat-shrinkable tube.

[0006] FIG. 1 is a schematic plan view showing an electric wire with a terminal according to a first embodiment. FIG. 2 is a schematic side view showing an electric wire with a terminal according to the first embodiment. FIG. 3 is a schematic plan view showing a terminal according to the first embodiment. FIG. 4 is a schematic plan view showing an insulated electric wire connected to the terminal according to the first embodiment. FIG. 5 is a schematic perspective view showing a state in which an insulated electric wire is connected to the terminal according to the first embodiment. FIG. 6 is a schematic perspective view showing a heat-shrinkable tube according to the first embodiment. FIG. 7 is a diagram showing a manufacturing process for an electric wire with a terminal according to the first embodiment. FIG. 8 is a diagram showing a manufacturing process for an electric wire with a terminal according to the first embodiment. FIG. 9 is a diagram showing a manufacturing process for an electric wire with a terminal according to the first embodiment. FIG. 10 is a schematic perspective view showing a state in which an insulated electric wire is connected to a terminal according to a second embodiment. FIG. 11 is a schematic perspective view showing an electric wire with a terminal according to the second embodiment. FIG. 12 is a schematic plan view showing a modified example of a terminal. FIG. 13 is a schematic plan view showing a modified example of a terminal. Fig. 14 is a photograph showing the state of the terminal-side end of the electric wire with terminal of the example after the heat-shrinkable tube has been shrunk. Fig. 15 is a photograph showing the state of the terminal-side end of the electric wire with terminal of the comparative example after the heat-shrinkable tube has been shrunk. Fig. 16 is a photograph showing the state of the wire-side end of the electric wire with terminal of the example after the heat-shrinkable tube has been shrunk. Fig. 17 is a photograph showing the state of the wire-side end of the electric wire with terminal of the comparative example after the heat-shrinkable tube has been shrunk.

[0007] [Problem to be Solved by the Present Disclosure] In the above-described electric wire with terminal, if a watertight member such as a heat-shrinkable tube cannot fill the connection portion between the terminal and the insulated electric wire without leaving any gaps, moisture may penetrate the connection portion between the terminal and the insulated electric wire through the gaps, which may cause electrical problems. Therefore, there is a need to fill the connection portion between the terminal and the insulated electric wire without leaving any gaps.

[0008] An object of the present disclosure is to provide an electric wire with a terminal that has good watertightness at the connection portion between the terminal and the insulated electric wire.

[0009] Effect of the Present Disclosure According to the present disclosure, it is possible to provide an electric wire with a terminal that has good watertightness at the connection portion between the terminal and the insulated electric wire.

[0010] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0011] The electric wire with terminal of the present disclosure comprises: (1) a plurality of insulated electric wires whose conductors are exposed from an insulating layer; a terminal electrically connected to the conductors; and a heat-shrinkable tube disposed on the terminal and covering the connection portion of the terminal, wherein the terminal has a mating connection portion electrically connected to a mating connection destination, a wire fixing portion to which the plurality of insulated electric wires are fixed, and a conductor connection portion provided between the mating connection portion and the wire fixing portion and to which the conductors are connected, wherein one or more through holes are provided in the conductor connection portion and the wire fixing portion, the heat-shrinkable tube covers the through holes, and an adhesive containing a thermoplastic resin as a main component is filled into the gap inside the heat-shrinkable tube.

[0012] In this electric wire with terminal, a heat-shrinkable tube covers the through-holes extending from the wire fixing portion to the conductor connecting portion, and an adhesive primarily composed of a thermoplastic resin is filled into the gaps inside the heat-shrinkable tube, thereby ensuring appropriate waterproofing of the connection between the terminal and the insulated wire. Furthermore, in this electric wire with terminal, one or more through-holes are provided in the region between the mating connection portion and the wire fixing portion, allowing the adhesive to permeate the entire area and fill the gaps evenly. Therefore, this electric wire with terminal has improved adhesive filling properties and provides good waterproofing of the connection between the terminal and the insulated wire. In this disclosure, the term "main component" refers to the component with the highest content, e.g., a component with a content exceeding 50% by mass. The term "wire fixing portion" refers to the portion where the electric wire is fixed by a wire fixing means such as crimping or fusion, and the surrounding area.

[0013] (2) In the above (1), the terminal may have side walls on at least some of the mating connection portion, the conductor connection portion, and the wire fixing portion, thereby further improving the mechanical strength of the terminal and limiting the position of the conductor of the insulated wire connected to the terminal.

[0014] (3) In the above (1) or (2), the total area of ​​the through holes of the terminals in a plan view is 15 mm２ 60mm or more ２ The total area of ​​the through holes of the terminals in a plan view may be 15 mm or less. ２ 60mm or more ２ By satisfying the condition below, the adhesive flows through the through holes and can be filled evenly over the entire surface.

[0015] (4) In the above (1) to (3), the total area of ​​the through holes of the terminals in a plan view is 20 mm ２ 60mm or more ２ The total area of ​​the through holes of the terminals in a plan view may be 20 mm or less. ２ 60mm or more ２ When the adhesive is less than 1 / 2 mm in area, the adhesive flows through the through holes, and the adhesive can be filled more evenly throughout the entire surface. Here, the "total area" means the sum of the areas of the through holes when there are multiple through holes.

[0016] (5) In the above (1) to (4), the viscosity of the adhesive at 130°C may be 500 Pa·s or more and 800 Pa·s or less. By having the viscosity of the adhesive at 130°C be 500 Pa·s or more and 800 Pa·s or less, the fluidity of the adhesive is improved, the uneven distribution of the adhesive is reduced, and the adhesive can be more effectively filled throughout. Here, the "viscosity at 130°C" is a value measured using a rheometer (dynamic viscoelasticity measuring device).

[0017] (6) In the above (1) to (4), the adhesive may have a viscosity of 550 Pa·s or more and 750 Pa·s or less at 130° C. By having the adhesive have a viscosity of 550 Pa·s or more and 750 Pa·s or less at 130° C., the fluidity of the adhesive is further improved, uneven distribution of the adhesive is reduced, and the adhesive can be more effectively filled throughout.

[0018] (7) In the above (1) to (6), the terminal may have one or more through holes in the conductor connection portion. By providing one or more through holes, the adhesive can be distributed throughout the entire area and evenly filled into gaps.

[0019] (8) In the above (1) to (6), the conductor connecting portion and the electric wire fixing portion of the terminal may each have a through hole. By providing a through hole in the conductor connecting portion and the electric wire fixing portion of the terminal, the adhesive is spread throughout and filled evenly into gaps.

[0020] (9) In the above (8), the area of ​​the through hole in the conductor connecting portion and the area of ​​the through hole in the electric wire fixing portion may be approximately equal in plan view. Since the area of ​​the through hole in the conductor connecting portion and the area of ​​the through hole in the electric wire fixing portion are approximately equal in plan view, the adhesive spreads throughout and fills gaps evenly. The area of ​​the through hole in the connecting portion and the area of ​​the through hole in the electric wire fixing portion in plan view being "approximately equal" means that the area of ​​the through hole in the connecting portion in plan view is within ±10% of the area of ​​the through hole in the electric wire fixing portion in plan view.

[0021] [Details of the embodiment of the present disclosure] A preferred embodiment of the present disclosure will be described.

[0022] <Electric wire with terminal> [First embodiment] The electric wire with terminal includes a plurality of insulated electric wires, a terminal, and a heat-shrinkable tube. The terminal has a mating connection portion electrically connected to a mating connection destination, a wire fixing portion to which the plurality of insulated electric wires are fixed, and a conductor connection portion provided between the mating connection portion and the wire fixing portion. Furthermore, one or more through holes are provided in the conductor connection portion and the wire fixing portion. The electric wire with terminal has one or more through holes in the conductor connection portion and the wire fixing portion, allowing adhesive to be evenly distributed throughout the gaps inside the heat-shrinkable tube. Therefore, waterproofing can be reliably achieved.

[0023] Fig. 1 is a schematic plan view of an electric wire with terminal 100 of the first embodiment. Fig. 2 is a schematic side view of the electric wire with terminal 100 of the first embodiment. Fig. 3 is a schematic plan view showing a terminal 20 of the first embodiment. The electric wire with terminal 100 includes a plurality of insulated electric wires 10 (two in this embodiment) whose conductors 12 are exposed from an insulating layer 14, terminals 20 electrically connected to the conductors 12, and a heat-shrinkable tube 30 covering the insulated electric wires 10 arranged in the terminals 20. The terminals 20 include a mating connection portion 22 electrically connected to a connection destination, a wire fixing portion 24 to which the insulated electric wires 10 are fixed, and a conductor connection portion 23 provided between the mating connection portion 22 and the wire fixing portion 24 and to which the conductors 12 are connected.

[0024] 4 is a schematic plan view showing two insulated wires 10 according to the first embodiment. The insulated wires 10 include a conductor 12 made of a conductive material and an insulating layer 14 made of an insulating material that covers the conductor 12. The conductor 12 is made of a conductive material such as copper, a copper alloy, aluminum, or an aluminum alloy. The insulating layer 14 is made of, for example, polyvinyl chloride (PVC), polyethylene, a fluororesin, or polyester.

[0025] (Terminal) The terminal 20 of this embodiment can be integrally formed, for example, by press-molding a metal plate, and has a simple flat structure without side walls. As shown in Fig. 3, the terminal 20 has a mating connection portion 22, a conductor connection portion 23, and a wire fixing portion 24. The terminal 20 has, in its tip region, the mating connection portion 22 for connection to a terminal connection portion of an electrical device or the like, and the wire fixing portion 24 for fixing the insulated wire 10. Between the mating connection portion 22 and the wire fixing portion 24, the conductor connection portion 23 for connecting the conductor 12 of the insulated wire 10 is provided. In this embodiment, the wire fixing portion 24 of the terminal 20 has two crimping claws 25 for crimping the insulating layer 14 of the insulated wire 10.

[0026] <Wire fixing portion> Fig. 5 is a schematic perspective view showing a state in which the insulated wires 10 are connected to the terminal 20 of the first embodiment. As shown in Fig. 5, one end of each of the two insulated wires 10 is attached to the terminal 20. As shown in Fig. 5, in the wire fixing portion 24, the insulated wires 10 are fixed by crimping the crimping claws 25 onto the insulating layers 14 of the two insulated wires 10.

[0027] The plurality of insulated wires 10 may be fixed by fusion at the wire fixing portion 24. In this case, the plurality of insulated wires 10 are fixed by melting and then solidifying a portion of the insulating layer 14 of each of the plurality of insulated wires 10.

[0028] 3, the wire fixing portion 24 is provided with a round through-hole 28 that exposes the insulating layer 14 of the insulated wire 10. This allows the adhesive 34 to pass through the through-hole 28 and spread evenly to the gaps in the insulating layer 14 of the insulated wire 10 at the wire fixing portion 24, leaving no gaps in the insulating layer 14 uncoated with adhesive 34. This further improves the watertightness of the electric wire with terminal 100.

[0029] 5 , a conductor connecting portion 23 for connecting the conductors 12 of the insulated wire 10 is provided between the mating connecting portion 22 and the wire fixing portion 24 of the terminal 20. The conductors 12 of the insulated wires 10, which are exposed by a predetermined length from the insulating layer 14 of each of the multiple insulated wires 10 and bundled together, are connected to the conductor connecting portion 23 of the terminal 20. The conductor connecting portion 23 electrically connects the conductors 12 of the insulated wire 10 to the terminal 20 in a state where it is thermocompression-bonded to the ends of, for example, two conductors 12. The conductor connecting portion 23 and the conductors 12 may be connected by ultrasonic welding, resistance welding, soldering, or the like.

[0030] <Mating Connection Portion> The mating connection portion 22 is provided in the tip region of the terminal 20. The mating connection portion 22 is a portion that is directly connected to a connecting partner, and is a generally oval, flat portion that is screwed to the terminal connection portion of the connecting partner, such as an electric device. A screw insertion hole 29 is formed in the center of the mating connection portion 22, through which a fastener such as a screw is passed to secure it to the connecting partner.

[0031] A round through-hole 27 is provided in the conductor connection portion 23. This allows the adhesive to pass through the through-hole 27 and spread evenly to gaps in the heat-shrinkable tube 30 that are distant from the tip of the conductor 12 in the insulated wire 10. Therefore, the water-stopping properties of the electric wire with terminal 100 can be further improved.

[0032] (Heat-shrinkable tube) A cylindrical heat-shrinkable tube 30 is used for waterproofing the electric wire with terminal 100. FIG. 6 is a schematic perspective view showing the heat-shrinkable tube 30 of the first embodiment. As shown in FIG. 6, the heat-shrinkable tube 30 before attachment has an adhesive layer 33 laminated on its inner surface. The adhesive layer 33 is formed of an adhesive. By having the adhesive layer 33 laminated on the inner surface of the heat-shrinkable tube 30, the electric wire with terminal 100 can easily improve the adhesion between the heat-shrinkable tube 30, the insulated electric wire 10, and the terminal 20, thereby improving waterproofing. The adhesive 34 in the electric wire with terminal 100 is filled by melting the heat-shrinkable tube 30 when heated and then cooling and solidifying.

[0033] As shown in FIG. 1 , the heat-shrinkable tube 30 covers the periphery from the wire fixing portion 24 to a position overlapping the through-hole 27 provided in the conductor connecting portion 23. More specifically, the heat-shrinkable tube 30 covers the periphery from the region of the two insulated wires 10 where the terminals 20 are fixed to the wire fixing portions 24 to the through-hole 27 provided in the conductor connecting portion 23 near the tip of the conductor 12 of the insulated wire 10. Therefore, the heat-shrinkable tube 30 covers the insulating layer 14 crimped by the wire fixing portion 24 and the end of the conductor 12 exposed from the insulating layer 14. Furthermore, gaps inside the heat-shrinkable tube 30 are filled with an adhesive 34 primarily composed of a thermoplastic resin. In other words, the terminal 20 is bonded without gaps by the adhesive 34 along the entire outer periphery from the wire fixing portion 24 to the through-hole 27 provided in the conductor connecting portion 23.

[0034] The heat-shrinkable tube 30 is a cylindrical member made of thermoplastic resin that has been shrunk by heating. Examples of the main components of the heat-shrinkable tube 30 include synthetic resins such as fluororesin, ionomer resin, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamide, polyethylene, and polyolefins such as polypropylene. Furthermore, the above synthetic resins may be crosslinked by ionizing radiation crosslinking or chemical crosslinking.

[0035] The adhesive 34 is mainly composed of, for example, polyamide, ethylene-vinyl acetate copolymer (EVA), olefin-based resin, or thermoplastic polyester.

[0036] The lower limit of the viscosity of the adhesive 34 at 130°C may be 500 Pa·s, 550 Pa·s, or 600 Pa·s. By setting the lower limit of the viscosity of the adhesive 34 at 130°C to 500 Pa·s, the adhesive 34 can adhere to the outer surfaces of the conductors 12 while sufficiently penetrating into the gaps between the conductors 12, thereby improving water-stopping properties. Furthermore, flow of the adhesive 34 is prevented in the usage environment, thereby maintaining sufficient water-stopping properties. Meanwhile, the upper limit of the viscosity of the adhesive 34 at 130°C may be 800 Pa·s, 750 Pa·s, or 700 Pa·s. By setting the upper limit of the viscosity of the adhesive 34 at 130°C to 800 Pa·s, the fluidity of the adhesive 34 when heated is improved, thereby enabling it to more sufficiently penetrate into the gaps between the heat-shrinkable tube 30, the multiple insulated electric wires 10, and the terminals 20.

[0037] The lower limit of the total area of ​​the through holes 27 and 28 of the terminal 20 in a plan view is 15 mm ２ 20 mm ２ 30 mm ２ 40 mm ２ The lower limit of the total area of ​​the through holes 27 and 28 of the terminal 20 in a plan view may be 15 mm ２This improves the fluidity of the adhesive 34, spreading the adhesive 34 throughout the entire area, and allowing for better filling of the adhesive 34. On the other hand, the upper limit of the total area of ​​the through holes 27 and 28 of the terminal 20 in a plan view is 60 mm ２ The upper limit of the total area of ​​the through holes 27 and 28 of the terminal 20 in a plan view may be 60 mm ２ This reduces unevenness in the flow of the adhesive 34, and allows the adhesive 34 to fill the gaps so as to flow evenly around them.

[0038] The viscosity of the adhesive 34 at 130°C is 500 Pa·s or more and 800 Pa·s or less, and the total area of ​​the through holes 27 and 28 of the terminal 20 in a plan view is 15 mm ２ 60mm or more ２ or less, the viscosity may be 550 Pa·s or more and 750 Pa·s or less, and the total area of ​​the through holes 27 and the through holes 28 in a plan view may be 20 mm ２ 60mm or more ２ or less, the viscosity may be 600 Pa·s or more and 700 Pa·s or less, and the total area of ​​the through holes 27 and the through holes 28 in a plan view may be 40 mm ２ 60mm or more ２ The viscosity of the adhesive 34 at 130° C. may be 500 Pa·s or more and 800 Pa·s or less, and the total area of ​​the through holes 27 and 28 of the terminal 20 in a plan view may be 15 mm ２ 60mm or more ２ By making the adhesive 34 equal to or less than this, the fluidity of the adhesive 34 is improved and uneven flow of the adhesive 34 is reduced, so that the adhesive 34 can be filled more efficiently over the entire area.

[0039] [Method for manufacturing electric wire with terminal] The method for manufacturing the electric wire with terminal includes a step of fixing an insulated electric wire to the electric wire fixing portion of the terminal (electric wire fixing step), a step of connecting a conductor to the terminal (conductor connecting step), and a step of attaching a heat shrink tube (heat shrink tube attaching step).

[0040] (Electric Wire Fixing Process) First, as shown in Fig. 4, the plurality of insulated wires 10 are processed so that a certain length of the insulating layer 14 is peeled off from around the conductor 12 at each end, i.e., so that a certain length of the end of the conductor 12 extends beyond the end of the insulating layer 14. Next, the crimping claws 25 of the wire fixing portion 24 of the terminal 20 are crimped, thereby fixing the insulating layer 14 to the terminal 20 as shown in Fig. 7.

[0041] (Conductor Connecting Step) In the conductor connecting step, terminals 20 are connected to conductors 12 at one ends of the plurality of insulated electric wires 10. Examples of methods for connecting the conductors 12 to the terminals 20 include a method of thermocompression bonding the conductors 12 at one ends of the plurality of insulated electric wires 10 to the conductor connecting portions 23 of the terminals 20. In the thermocompression bonding process, for example, the conductor connecting portion 23 and the conductors 12 at one ends of the plurality of insulated electric wires 10 arranged on the upper surface of the conductor connecting portion 23 are sandwiched between a pair of upper and lower electrode members, and a predetermined pressure is applied while electricity is passed through the electrodes to heat the conductors 12 at a predetermined length exposed from the insulating layer 14 to the conductor connecting portions 23. In addition to the thermocompression bonding, ultrasonic welding, resistance welding, soldering, and the like may also be used to connect the conductors 12 to the terminals 20.

[0042] (Heat-Shrink Tube Attachment Process) In the heat-shrink tube attachment process, as shown in Fig. 8 , one end of each of a plurality of insulated electric wires 10, each having a terminal 20 connected to one end, is inserted into a pre-shrunk heat-shrink tube 30 and positioned so as to cover the area from the electric wire fixing portion 24 to the through-hole 27 provided in the conductor connecting portion 23. After the heat-shrink tube 30 having the adhesive layer 33 is attached, the heat-shrink tube 30 is heated by a heating device to heat-shrink the heat-shrink tube 30, melting the adhesive layer 33 and spreading the adhesive 34 throughout the gaps inside the heat-shrink tube 30. The heat-shrink tube 30 is then brought into close contact with each insulated electric wire 10 to which a terminal 20 is connected, thereby waterproofing the connection between the terminal 20 and the insulated electric wire 10. In this manner, a terminal-attached electric wire 100 having a heat-shrink tube 30 attached thereto, as shown in Fig. 9 , is obtained.

[0043] [Second embodiment] In the first embodiment described above, the mating connection portion, the conductor connection portion, and the wire fixing portion have a simple flat structure without side walls. However, in the second embodiment, the terminal has side walls on at least some of the mating connection portion, the conductor connection portion, and the wire fixing portion.

[0044] FIG. 10 is a schematic perspective view showing a state in which an insulated wire 10 is connected to a terminal 40 of the second embodiment. FIG. 11 is a schematic perspective view showing a terminal-fitted wire 200 according to the second embodiment. As shown in FIGS. 10 and 11 , in the terminal-fitted wire 200 according to the second embodiment, the cross-sectional shape of the terminal 40 is U-shaped with the opening facing upward. The terminal-fitted wire 200 has a pair of side walls 41, the leading end of which extends to the middle of the mating connection portion 42 and the rear end of which extends to the wire fixing portion 44. The side walls 41 regulate the position of the conductor 12 of the insulated wire 10 to be connected and improve the mechanical strength of the terminal 40. The side walls 41 extend from the wire fixing portion 44 to the middle of the mating connection portion 42, specifically to the vicinity of the conductor connecting portion 23 at the base end of the mating connection portion 22. The pair of side walls 41 have a shape in which a portion of each of the pair of side walls 41 is constricted so as to narrow the distance between them. Furthermore, in the wire fixing portion 44, the insulated wires 10 are fixed by crimping crimping claws 45 onto the insulating layers 14 of the two insulated wires 10. A round through-hole 47 is provided near the conductor connecting portion 43 at the base end of the mating connecting portion 42. A screw insertion hole 49 is formed in the center of the mating connecting portion 42, through which a fastener such as a screw is passed to fix the mating connecting portion 42 to the connecting portion.

[0045] In the second embodiment, the terminal 40 has side walls 41 on at least a portion of the mating connection portion 42, the conductor connection portion 43, and the wire fixing portion 44, which improves the mechanical strength of the terminal 40 and makes it difficult for the position of the conductor 12 of the connected insulated wire 10 to move.

[0046] In this electric wire with terminal, one or more through holes are provided in the conductor connecting portion and the wire fixing portion, which allows the adhesive to spread throughout and fill gaps evenly. Therefore, this electric wire with terminal has improved adhesive filling properties and can achieve good watertightness at the connection portion between the terminal and the insulated wire.

[0047] In the electric wire with terminal, the shape of the mating connection part may be changed as appropriate to match the mating connection part, and the shapes of the conductor connection part and the electric wire fixing part may also be changed as appropriate in accordance with the shape of the mating connection part.

[0048] In the above embodiment, the electric wire with terminal includes two insulated electric wires, but it may include a greater number of insulated electric wires.

[0049] In the first embodiment, the through holes are circular, but the shape of the through holes is not particularly limited. The through holes may be circular, square, horizontally elongated oval, rectangular, or polygonal (triangular, quadrangular). Furthermore, the conductor connection portion and the wire fixing portion of the terminal may each have multiple through holes. FIGS. 12 and 13 are schematic plan views showing modified terminals. In the terminal 50 of FIG. 12 , the leading ends of a pair of side walls 51 extend partway to the mating connection portion 52, and the trailing ends extend to the wire fixing portion 54. A rectangular through hole 57 is provided in the conductor connection portion 53 of the mating connection portion 52, and a rectangular through hole 58 is provided in the wire fixing portion 54. Furthermore, the wire fixing portion 54 is provided with two crimping claws 55 for crimping the insulation layer of the insulated wire. A screw insertion hole 59 is formed in the center of the mating connection portion 52, through which a fastener such as a screw is inserted for securing the terminal to a mating connection. In the terminal 60 shown in FIG. 13 , the leading ends of a pair of side walls 61 extend partway through the mating connection portion 62, and the trailing ends extend to the wire fixing portion 64. Two circular through holes 67 are formed in the conductor connection portion 63, and two circular through holes 68 are formed in the wire fixing portion 64. The terminal 50 has side walls 51, and the terminal 60 has side walls 61. This improves the mechanical strength of the terminals 50 and 60 and also regulates the position of the conductor of the insulated wire connected to the terminal 50. The wire fixing portion 64 also has two crimping claws 65 for crimping the insulating layer of the insulated wire. A screw insertion hole 69 is formed in the center of the mating connection portion 62, through which a fastener such as a screw is inserted for securing the terminal to a mating connection.

[0050] Alternatively, multiple through holes may be provided in either the conductor connecting portion or the wire fixing portion. This is because, depending on the terminal structure, providing multiple through holes in one portion may allow the adhesive to spread throughout and fill gaps evenly. Furthermore, through holes with approximately the same area in a plan view may be provided in each of the conductor connecting portion and the wire fixing portion. This is because providing through holes with approximately the same area in a plan view may allow the adhesive to spread evenly throughout and fill gaps evenly.

[0051] In the above embodiment, an adhesive layer is laminated on the inner surface of the heat-shrinkable tube before attachment, but instead of the adhesive layer, a resin film formed solely from an adhesive may be used.

[0052] The present disclosure will be explained in more detail below using experimental examples, but the present disclosure is not limited to these experimental examples.

[0053] <Tests No. 1 to No. 17> [Preparation of Electric Wire with Terminal] Terminals having the shape shown in FIG. 10 were prepared from tin-plated copper alloy material. The terminal width was 7.0 mm, the plate thickness was 1.0 mm, and the length of the flat portion was 10 mm. Furthermore, as shown in FIG. 10, one through-hole was provided near the conductor connection portion of the mating connection portion and one near the wire fixing portion. The total area of ​​the through-holes in a plan view is shown in Table 1. Next, an insulated electric wire having a conductor made of a stranded wire was prepared, and after removing the insulating layer from the end, it was crimped and fixed with the crimping claws of the wire fixing portion of the terminal as shown in FIG. 10. In all samples, two insulated electric wires were connected to a common terminal. Next, the conductor was soldered to the conductor connection portion of the terminal.

[0054] Next, the insulated wires to be placed on the terminals were covered with heat-shrinkable tubing having a thickness of approximately 0.4 mm and an adhesive layer formed from an adhesive having a viscosity at 130°C as listed in Table 1. The heat-shrinkable tubing with the adhesive layer laminated thereon was then heated to 130°C using a heater. This caused the heat-shrinkable tubing to shrink and the adhesive layer to melt, resulting in the production of each terminal-attached wire. The heat-shrinkable tubing was primarily composed of cross-linked polyethylene, and had a radial heat shrinkage rate of 80%. The shrinkage temperature of the heat-shrinkable tubing was 135°C. The total mass of the adhesive layer was approximately 13 g. The heat-shrinkable tubing had an inner diameter before heat shrinkage of approximately 19.0 mm, a thickness before heat shrinkage of approximately 0.80 mm, an inner diameter after heat shrinkage of approximately 3.8 mm, a thickness after heat shrinkage of approximately 2.61 mm, and a length of approximately 65 mm. The radial heat shrinkage rate (%) was calculated using the following formula: Radial heat shrinkage rate (%) = (inner diameter before heat shrinkage - inner diameter after heat shrinkage) / inner diameter before heat shrinkage x 100 <Test No. 18> An electric wire with terminal was produced in the same manner as in Test No. 1, except that a terminal having no through-holes was used in the vicinity of the conductor connection portion and in the electric wire fixing portion of the mating connection portion.

[0055] [Evaluation] The filling properties of the adhesive of the electric wires with terminals of Tests No. 1 to No. 18 obtained above were evaluated according to the following method. The evaluation results are shown in Table 1.

[0056] (Viscosity of adhesive) The viscosity of the adhesive was measured using a rheometer manufactured by Anton Paar as a viscometer, while applying shear under conditions of 130°C and a shear rate of 10 / s.

[0057] (Adhesive Filling Ability) Regarding the adhesive filling ability of the terminal-attached electric wires of Test No. 1 to No. 18, the appearance of the adhesive after heat shrinkage of the heat shrink tubing was observed. Specifically, each sample was observed from the side, and the state of adhesive outflow from both ends of the heat shrink tubing was visually evaluated for appearance. The results were evaluated on a five-point scale from A to E according to the following evaluation criteria: A: Almost no adhesive outflow from both ends of the heat shrink tubing. B: A small amount of adhesive outflow from both ends of the heat shrink tubing. C: A moderate amount of adhesive outflow from both ends of the heat shrink tubing. D: A large amount of adhesive outflow from both ends of the heat shrink tubing. E: A considerable amount of adhesive outflow from both ends of the heat shrink tubing.

[0058] Photographs of the state of adhesive outflow from both ends of the heat-shrinkable tube are shown in Figures 14 to 17 for Test No. 18, which used a terminal that did not have through holes near the conductor connection portion of the mating connection portion or in the electric wire fixing portion, and Test No. 15, which was manufactured under the same conditions as Test No. 18 except that a terminal with a through hole was used. A photograph of the state of the end of the heat-shrinkable tube on the mating connection portion side in Test No. 15 is shown in Figure 14, and a photograph of the state of the end of the heat-shrinkable tube on the electric wire fixing portion side is shown in Figure 16. Furthermore, a photograph of the state of the end of the heat-shrinkable tube on the mating connection portion side in Test No. 18 is shown in Figure 15, and a photograph of the state of the end of the heat-shrinkable tube on the electric wire fixing portion side is shown in Figure 17.

[0059]

[0060] In the appearance evaluation of the adhesive after heat shrinkage of the heat-shrinkable tubing, Test No. 18, which used a terminal without through-holes in the conductor connection portion and the wire fixing portion of the mating connection part, showed a considerable amount of adhesive leaking out from both ends of the heat-shrinkable tubing, as shown in Figures 15 and 17. This is thought to be because Test No. 18, which used a terminal without through-holes in the conductor connection portion and the wire fixing portion of the mating connection part, had few paths for the adhesive to flow into, preventing it from reaching the gaps inside the heat-shrinkable tubing, and causing a large amount of adhesive to leak out from both ends of the heat-shrinkable tubing. In contrast, Test No. 15, which was manufactured under the same conditions except for using a terminal with through-holes in both the conductor connection portion and the wire fixing portion of the mating connection part, showed only a small amount of adhesive leaking out from both ends of the heat-shrinkable tubing, as shown in Figures 14 and 16. For this reason, Test No. 1 to Test No. 15 were manufactured under the same conditions except for using a terminal with through-holes in both the conductor connection portion and the wire fixing portion of the mating connection part. In the case of the terminal-attached wire shown in FIG. 17, which has through holes in two areas, the conductor connection portion and the wire fixing portion, at the mating connection portion of the terminal, the adhesive is spread throughout the entire wire and is filled evenly into the gaps, which is thought to reduce the amount of adhesive leaking out from both ends of the heat-shrinkable tube.

[0061] As shown in Table 1, the adhesive filling property is such that the viscosity of the adhesive at 130°C is 500 Pa·s or more and 800 Pa·s or less, and the total area of ​​the through holes in the terminal in a plan view is 15 mm ２ 60mm or more ２ In the electric wires with terminals of Test Nos. 5 to 8 and Test Nos. 13 to 17, in which the viscosity at 130°C of the adhesive was 600 Pa·s or more and 700 Pa·s or less, and the total area of ​​the through holes in the terminals in a plan view was 40 mm or less, the filling property of the adhesive was more favorable. ２ 60mm or more ２ In the electric wires with terminals of Tests No. 14 to No. 16 shown below, the filling property of the adhesive was superior.

[0062] The above results demonstrate that the electric wire with terminal can improve the filling property of the adhesive and can provide good watertightness at the connection portion between the terminal and the insulated electric wire.

[0063] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is not limited to the configurations of the above-described embodiments, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

[0064] REFERENCE SIGNS LIST 10 Insulated wire 12 Conductor 14 Insulating layer 20, 40, 50, 60 Terminal 22, 42, 52, 62 Mating connection portion 23, 43, 53, 63 Conductor connection portion 24, 44, 54, 64 Wire fixing portion 25, 45, 55, 65 Crimping claw 27, 28, 47, 57, 58, 67, 68 Through hole 29, 49, 59, 69 Screw insertion hole 30 Heat shrinkable tube 33 Adhesive layer 34 Filled adhesive 41, 51, 61 Side wall 100, 200 Terminal-attached wire

Claims

1. An insulated electric wire with terminal comprising: a plurality of insulated electric wires whose conductors are exposed from an insulating layer; terminals electrically connected to the conductors; and heat-shrinkable tubing disposed on the terminals and covering the connection portions of the terminals, wherein the terminals have a mating connection portion electrically connected to a mating connection destination, a wire fixing portion to which the plurality of insulated electric wires are fixed, and a conductor connection portion provided between the mating connection portion and the wire fixing portion and to which the conductors are connected, wherein one or more through holes are provided in the conductor connection portion and the wire fixing portion, the heat-shrinkable tubing covers the through holes, and the gaps inside the heat-shrinkable tubing are filled with an adhesive whose main component is a thermoplastic resin.

2. The electric wire with terminal according to claim 1, wherein the terminal has side walls on at least a part of the mating connection portion, the conductor connection portion and the electric wire fixing portion.

3. The total area of ​​the through holes of the terminals in plan view is 15 mm ２ 60mm or more ２ The electric wire with terminal according to claim 1 or 2, wherein:

4. The total area of ​​the through holes of the terminals in plan view is 20 mm ２ 60mm or more ２ The electric wire with terminal according to claim 1 or 2, wherein:

5. An electric wire with terminal according to any one of claims 1 to 4, wherein the viscosity of the adhesive at 130°C is 500 Pa·s or more and 800 Pa·s or less.

6. An electric wire with terminal according to any one of claims 1 to 4, wherein the viscosity of the adhesive at 130°C is 550 Pa·s or more and 750 Pa·s or less.

7. An electric wire with terminal according to any one of claims 1 to 6, wherein one or more through holes of the terminal are present in the conductor connection portion.

8. An electric wire with terminal according to any one of claims 1 to 6, wherein the conductor connecting portion and the electric wire fixing portion of the terminal each have a through hole.

9. The electric wire with terminal according to claim 8, wherein the area of ​​the through hole in the conductor connecting portion in a plan view is substantially equal to the area of ​​the through hole in the electric wire fixing portion in a plan view.

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