JP2017111883A - Crimp terminal and wire with terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for connection of a crimp terminal and a wire with an electrically low contact resistance and a mechanically strong retention, even if a serration (uneven pattern) is not formed on the crimp terminal by using a molding die.SOLUTION: A wire with a terminal includes a wire 11 having a conductor part 13, and a crimp terminal 12 having a crimp part 16 crimped to the conductor part 13 of the wire 11. On the contact interface of the conductor part 13 and crimp part 16, a buffer layer 21 formed of resin, plating or grease is interposed. In the buffer layer 21, conductive fine grains having a fractal structure including micro protrusions on the surface are mixed and dispersed. The fine grains in the buffer layer 21 break through a passive film existing on the surface of the conductor part 13 and come into contact therewith.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crimp terminal and an electric wire with a terminal.

  As a crimping terminal for electric wires in which the conductor part is composed of a single wire or a plurality of strands of Al (aluminum) or aluminum alloy, an uneven pattern called “serration” is provided on the contact surface on the crimping terminal side crimped to the conductor part. Techniques have been presented (see, for example, Patent Document 1 and Non-Patent Document 1). In this technique, a non-conductive film (such as an oxide film or a contaminated organic film) formed on the surface of an aluminum wire is broken by a concavo-convex pattern provided on the contact surface of the crimp terminal, whereby the aluminum wire is applied to the crimp surface. While the metal part is exposed to electrically connect the electric wire and the crimp terminal, the pressure on the contact surface is increased by the concave / convex pattern, thereby strengthening the holding force of the crimp terminal on the electric wire. On the other hand, conventionally, an electric wire in which a conductor portion is composed of a copper wire is also common. The concave / convex pattern employed for serration of this type of crimp terminal for electric wires is often composed of only a few groove shapes. For this reason, the pressing mold for forming the serration has a relatively simple shape.

  In addition, for the concave / convex pattern of serrations formed on the crimp part of the crimp terminal, various concave shapes such as parallelogram, pentagon, hexagon, octagon, etc. are conceivable as the square shape of each concave portion constituting them. ing. In particular, when the angle of the polygonal concave portion is larger than 90 degrees, the end portion (edge) region of the concave portion can be set wide, so that the end surface portion that bites into the conductor portion of the electric wire can be expanded in a wide range. As a result, the connection holding force between the electric wire and the crimp terminal is strengthened, the mechanical connection performance is improved, and the area to be fitted into the conductor portion of the electric wire is increased. In addition, since the contact pressure increases at the crimping portion between the electric wire and the crimping terminal, it is known that the electrical connection performance can be improved (see, for example, Patent Document 2).

  In addition, when serrations are provided on crimp terminals, in order to cope with various strands and wire diameters, material characteristics, strand wire structures, etc., the arrangement direction of depressions or projections constituting the serrations, irregularities It is known that it is necessary to optimize the interval between the portions, the depth of the uneven portion, and the angle in the depth (height) direction. Furthermore, it has been suggested that it is important to strictly control a molding die for forming these uneven serration patterns (see, for example, Patent Document 3).

  On the other hand, as an alternative to crimping terminals with serrations, before crimping the conductor part (part to be crimped) of a wire composed of multiple strands to the crimping terminal, hard conductive powder harder than the strand material is used. A technique of applying to a conductor portion of an electric wire is known (for example, see Patent Document 4). In this technique, metal powder of copper, nickel, tungsten, molybdenum having a particle size of 70 to 200 mesh is used as hard conductive powder harder than the conductor portion of the wire made of annealed copper or copper alloy wire. A bonding method is adopted in which the wire is applied to the conductor portion of the electric wire and then crimped with a crimp terminal.

  In the above-mentioned alternative technology, the conductive powder bites into the strands relatively easily due to the pressure applied during crimping, and the non-conductive film on the conductor surface is destroyed. Therefore, bonding by direct connection of metals under the non-conductive film is possible. become. Moreover, since the force at the time of crimping is concentrated on the conductive powder having a small contact area, the conductive powder sufficiently penetrates the element wire with a relatively small force. For this reason, even when a thermal shock, mechanical vibration, or the like under a rapid temperature cycle is applied to the crimp terminal or the electric wire, a stable electrical connection state can be maintained.

  As another alternative technique, a material molecular crystal (carbide or oxide) having a hardness higher than that of the non-conductive coating formed on the conductor surface of the electric wire is formed on the inner surface of the crimped portion of the crimp terminal where the conductor portion of the electric wire contacts. Etc.) is also known (see, for example, Patent Document 5). In this technique, the plating layer formed on the inner surface of the crimped portion of the crimp terminal shears and breaks the non-conductive coating on the conductor surface by the pressure applied during crimping (during crimping), thereby crimping the crimp terminal. The conductor part of the electric wire can be stably connected to the part via the plating layer.

JP 2010-3584 A JP 2011-81911 A JP 2012-9178 A JP-A-8-321331 JP 2004-193073 A

Norio Yamano, “SEI Technical Review”, “Development of Aluminum Harness”, July 2011, No. 179, p. 81-88

However, the above conventional techniques have the following problems.
First, in the techniques described in Patent Documents 1-3 and Non-Patent Document 1, depending on the material characteristics, thickness and length, shape, strand strand state, and usage environment of the electric wires to be connected, Therefore, it is necessary to produce a molding die for forming precise and fine serrations (concave / convex patterns) suitable for the purpose. In other words, in the manufacture of crimp terminals, it is necessary to prepare a molding die for serration formation each time depending on the product type of the electric wire to be connected. For this reason, a wide variety of molding dies must be produced, resulting in a significant cost increase. Therefore, the cost reduction effect which is one of the advantages of the aluminum-based electric wire cannot be obtained.

  In addition, with respect to a molding die for forming serrations, it is required to strictly manage a change with time accompanying mass production in order to stably manufacture a crimp terminal that maintains a desired high joining performance. However, as the types of crimp terminals and electric wires to be connected thereto increase, a wide variety of serration shapes are required, and the types of molds for forming serrations increase accordingly. For this reason, it is indispensable to periodically check the accuracy of serration formation for each product type. As a result, the management of the molding die becomes complicated. In addition, there is a possibility of inducing a decrease in yield due to omission of management of the molding die.

  In particular, the edge portion of the edge of the concavo-convex pattern provided in the molding die for serration formation is sag (disintegrated) due to repeated press work for many years. Specifically, the edge portion of the concave / convex pattern of the molding die is gradually rounded as the sharpness is lost due to the progress of wear, and the edge angle changes from a sharp angle to an obtuse angle into a smooth and gentle shape. I will do it. When a serration is formed on a crimping terminal using the molding die thus worn, and the conductor part of the electric wire is crimped using the crimping terminal, it becomes impossible to cause a desired pressure state and shear fracture in the serration part. . As a result, there arises a problem that the non-conductive film covering the conductor surface of the electric wire cannot be sufficiently penetrated and good connection performance cannot be obtained.

  On the other hand, in the technique described in Patent Document 4, the conductive powder itself having an irregular and non-uniform particle size is directly attached to the conductor surface of the electric wire. For this reason, there is a problem that workability is poor for attaching conductive powder to a curved surface having a complicated surface shape such as an electric wire, and the throughput of the crimp terminal connection process is reduced. Furthermore, since the conductor surface such as a stranded wire composed of a plurality of strands is uneven, it is difficult to uniformly and uniformly adhere the conductive powder thereto. For this reason, the dispersion of the conductive powder becomes uneven on the conductor surface, and unevenness occurs in the applied pressure at the places where the conductive powder is placed on the conductor surface during caulking. As a result, the non-conductive film covering the conductor surface is only partially broken, which makes the contact state of the inner surface of the crimped portion unstable and makes it difficult to achieve a desired contact resistance. was there.

  In the technique described in Patent Document 5, a plating layer in which material molecular crystals having a hardness higher than that of the non-conductive coating is provided on the inner surface of the crimped portion of the crimp terminal is dispersed in the plating layer. The surface shape and size of the material molecular crystal itself are not precisely controlled. For this reason, the surface of the material molecular crystal is smooth or forms a random and irregular irregular surface. Therefore, the pressure applied to the non-conductive film through the material molecular crystal at the time of caulking becomes non-uniform at each position, and when the same force is applied, the non-conductive film cannot be sufficiently destroyed and the contact resistance is reduced. It is conceivable that a location where the holding force becomes high or a location where the holding force is weakened due to a creep phenomenon due to excessive penetration of the electric wire into the strand is considered. As a result, there is a problem that the low electrical contact resistance and the mechanically strong holding force cannot be stably maintained (realized), which causes a decrease in yield in the crimp terminal connection process.

  In addition, there is terminal bonding using welding in addition to the above-described mechanical bonding. However, the terminal connection by welding is lower in strength at the time of tearing than the mechanical pressure bonding that pressurizes and crimps the electric wire to the terminal, so a new mechanism and structure to keep the welded part from moving Improvement is needed. Further, when a thin electric wire is welded, there is a problem such as a decrease in mechanical strength of the welded portion and an increase in contact resistance because the deterioration due to the thinning or alteration of the electric wire is remarkable.

  The main object of the present invention is to provide a mechanically strong holding force between the crimping terminal and the electric wire with low electrical contact resistance without forming a serration (uneven pattern) using a molding die on the crimping terminal. It is in providing the technique which can be connected by.

According to one aspect of the invention,
While having a crimping part to be crimped to the conductor part of the electric wire,
Comprising a buffer layer formed on the surface of the crimping portion that contacts the conductor portion;
The buffer layer is formed of resin, plating or grease,
The buffer layer is provided with a crimp terminal in which conductive fine particles having a fractal structure with fine protrusions on the surface are mixed and dispersed.

According to another aspect of the invention,
An electric wire with a terminal comprising: an electric wire having a conductor portion; and a crimp terminal having a crimp portion crimped to the conductor portion of the electric wire,
A buffer layer formed of resin, plating or grease is interposed at the contact interface between the conductor portion and the crimp portion,
In the buffer layer, conductive fine particles having a fractal structure with fine protrusions on the surface are mixed and dispersed,
The particulate matter in the buffer layer is provided with a terminal-attached electric wire that breaks through a non-conductive film existing on the surface of the conductor portion and is in contact with the conductor portion.

  According to the present invention, a crimp terminal and an electric wire are connected with a low electrical contact resistance and mechanically strong holding force without forming serrations (concave / convex patterns) using a molding die on the crimp terminal. It becomes possible to do.

BRIEF DESCRIPTION OF THE DRAWINGS The structure of the crimp terminal which concerns on 1st Embodiment of this invention and an electric wire with a terminal provided with this is demonstrated, (a) is a side view, (b) is a top view, (c) is A- in (b). It is A 'sectional drawing. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a structure of a fine particle body according to an embodiment of the present invention, where (a) is a conceptual diagram thereof, and (b) is an SEM (scanning electron microscope) observation image of the fine particle body actually produced by the present inventors. . (A), (b) is sectional drawing explaining the structural example of the fine particle body which concerns on embodiment of this invention, respectively. (A)-(d) is a figure explaining the other structure of the microparticles | fine-particles body based on embodiment of this invention. (A)-(c) is sectional drawing which shows the state after the crimping | compression-bonding of a conductor part and a crimping | compression-bonding part, respectively. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the structure of the crimp terminal which concerns on embodiment of this invention, and an electric wire with a terminal, Comprising: (a) is an exploded perspective view which shows the state before crimping, (b) is the state which attached the crimp terminal to the electric wire. It is a perspective view shown, (c) is an AA 'sectional view in (b). It is a figure explaining the manufacturing method of the electric wire with a terminal in the case of forming a buffer layer in a sheet form, (a) is an exploded perspective view showing the state before crimping, and (b) attached a buffer layer to a conductor part. It is a perspective view which shows a state, (c) is a perspective view which shows the state which attached the crimp terminal to the electric wire, (d) is AA 'sectional drawing in (c). It is a figure explaining the manufacturing method of the electric wire with a terminal in case a buffer layer is formed in a sleeve shape, (a) is an exploded perspective view showing the state before pressure bonding, and (b) has attached a buffer layer to a conductor part. It is a perspective view which shows a state, (c) is a perspective view which shows the state which attached the crimp terminal to the electric wire, (d) is AA 'sectional drawing in (c). It is a figure explaining the manufacturing method of the electric wire with a terminal in the case of forming a buffer layer in cap shape, (a) is an exploded perspective view showing the state before crimping, and (b) has attached a buffer layer to a conductor part. It is a perspective view which shows a state, (c) is a perspective view which shows the state which attached the crimp terminal to the electric wire, (d) is AA 'sectional drawing in (c). It is a figure explaining the structural example of a sleeve-shaped buffer layer, Comprising: (a) is a perspective view, (b) is a side view, (c) is a front view. It is a figure explaining the structural example of a cap-shaped buffer layer, Comprising: (a) is a perspective view, (b) is a side view, (c) is a front view. It is a figure explaining the other structural example of a sleeve-shaped buffer layer, (a) is a perspective view, (b) is a side view, (c) is a front view. It is a figure explaining the other structural example of a cap-shaped buffer layer, Comprising: (a) is a perspective view, (b) is a side view, (c) is a front view. (A)-(c) is a figure explaining the example which connects a conductor part and a crimping | compression-bonding part with the fine particle body of a large particle size. (A)-(c) is a figure explaining the example which connects a conductor part and a crimping | compression-bonding part with the microparticles | fine-particles of a small particle diameter. (A)-(c) is a figure explaining the example which arranged the fine particle body vertically in the buffer layer. (A)-(c) is a figure explaining the method of controlling the arrangement | sequence of microparticles | fine-particles using a jig | tool. (A)-(c) is a figure explaining the example which mixes two types of microparticles | fine-particles in a buffer layer, and connects a conductor part and a crimping | compression-bonding part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
1A and 1B illustrate a configuration of a crimp terminal according to a first embodiment of the present invention and a terminal-equipped electric wire including the crimp terminal. FIG. 1A is a side view, FIG. 1B is a top view, and FIG. It is AA 'sectional drawing in. In addition, in FIG. 1, the state before crimping | bonding a crimp terminal to an electric wire is shown.

(Wire with terminal)
The electric wire with terminal 10 includes an electric wire 11 and a crimp terminal 12. The “wire” in the present invention includes not only a so-called insulated wire in which a conductor is coated with an insulating coating, but also a “cable” in which the outermost layer is coated with a sheath. Accordingly, the “wire with terminal” in the present invention includes a “cable with terminal” including a cable and a crimp terminal.

(Electrical wire)
The electric wire 11 includes a conductor portion 13 serving as a core wire and a covering portion 14 that covers the conductor portion 13. The conductor 13 may be composed of a single strand or may be composed of a plurality of strands. In this embodiment, the conductor 13 is composed of a plurality of strands 13a. Moreover, the conductor part 13 is comprised by twisting together several metal strands 13a. The strand 13a which comprises the conductor part 13 consists of metal fine wires, such as Al (aluminum), Al alloy, Cu (copper), Cu alloy, for example. In this embodiment, as an example, the conductor part 13 shall be comprised by twisting together the several strand 13a which consists of Al or Al alloy.

  The covering portion 14 concentrically covers the conductor portion 13 having a substantially circular cross section. The covering portion 14 is made of an insulating material (for example, a synthetic resin). At the end of the electric wire 11, the covering portion 14 is peeled off, and the conductor portion 13 is exposed.

(Crimp terminal)
The crimp terminal 12 is made of, for example, Cu or Cu alloy. When the crimp terminal 12 is manufactured by forging, in order to improve castability (decrease castability factor), other metal elements may be added with Cu or Cu alloy as a main component. Specifically, in order to improve castability, other transition metal elements such as Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel) and the like are added. Also good. Or you may add noble metal elements, such as Pd (palladium), Ir (iridium), Pt (platinum), Au (gold). Thereby, the electric wire with a terminal excellent in manufacturability is realizable.

  The crimp terminal 12 holds a connection part 15 for connecting an object to be electrically connected (energized), a crimp part 16 to be crimped to the conductor part 13 of the electric wire 11, and a covering part 14 of the electric wire 11. And a gripping portion 17 for integrating. The connecting portion 15, the crimping portion 16, and the gripping portion 17 are integrally formed so as to be sequentially connected in the left-right direction in FIG. The connecting portion 15 is formed in a U shape in plan view. The crimping portion 16 has a pair of left and right side wall portions 18 and a lower wall portion 19 that connects the end portions of the side wall portions 18. The crimping part 16 is formed in a concave shape as shown in FIG. 1C in a state before the crimping, and the gripping part 17 is also formed in a concave shape like the crimping part 16. The crimping portion 16 is formed so as to be able to accommodate the conductor portion 13 of the electric wire 11, and the gripping portion 17 is formed so as to be able to accommodate the covering portion 14 of the electric wire 11.

  A buffer layer 21 is formed on the inner surface of the crimping portion 16. The buffer layer 21 is formed so as to cover the inner surface of the crimping part 16. The inner surface of the crimping portion 16 is a surface that comes into contact with the conductor portion 13 when the crimping portion 16 is crimped to the conductor portion 13 of the electric wire 11. When the crimping part 16 is formed by the pair of side wall parts 18 and the lower wall part 19 as described above, the buffer layers 21 are respectively formed on the opposing surfaces of the pair of side wall parts 18 and the upper surface of the lower wall part 19. It is formed.

(Buffer layer)
The buffer layer 21 is formed of a resin, plating, or grease (compound) that has a waterproof and corrosion-resistant action on the conductor portion 13 and the crimping portion 16. In the buffer layer 21, conductive fine particles are mixed (blended) and dispersed. A large number (a plurality) of the fine particles are mixed in the buffer layer 21 at a predetermined ratio. When the material constituting the base layer of the buffer layer 21 is an insulating material (for example, resin), conductivity is imparted to the buffer layer 21 by the fine particles mixed and dispersed in the buffer layer 21.

(Fine particles)
Here, the fine particles mixed and dispersed in the buffer layer 21 will be described.
2A and 2B illustrate the structure of a fine particle according to an embodiment of the present invention. FIG. 2A is a conceptual diagram, and FIG. 2B is an SEM (scanning electron microscope) observation of the fine particle actually produced by the present inventor. It is a statue.
The illustrated fine particle body 1 has a fractal structure (including a similar structure). A plurality of fine minute protrusions 2 are formed on the surface of the fine particle body 1. Regarding the diameter size of the fine particles 1, the lattice constant level of the crystal unit cell, for example, in the case of Ni, can be set to a minimum value of about 0.352 nm of the face-centered cubic lattice. Here, a fractal structure is a structure that has a figure that is “similar” to the whole object, no matter how small the object is cut out in a very small area. Refers to the structure shown. From a mathematical point of view, the structure has a non-integer dimension different from one dimension, two dimensions, and three dimensions. A typical example of a fractal structure is a Koch figure. Fractal structures also exist in nature. As specific examples, confetti, snow crystals, coastline, tree branches and leaves (leaf veins) are known as fractal structures. The fine particle body 1 has a large number of microprojections 2 on the surface. For this reason, fine irregularities due to a large number of minute protrusions 2 exist on the surface of the fine particle body 1. Regarding the uneven size of the microprojections 2, the atomic radius level that can be a minimum value that can be materialized as a fractal structure in nature, for example, in the case of Ni, can be about 0.124 nm. The fine particle body 1 is formed in a spherical shape as a whole. Incidentally, the diameter of the fine particle body 1 shown in FIG. 2B is about 5 μm.

  It is preferable that the tip curvature radius of the microprotrusions 2 arranged on the surface of the fine particle body 1 is 0.03 nm or more and 500 nm or less. In addition, when the fine particle 1 is spherical as described above, the tip curvature radius of the microprojection 2 is preferably 0.0006% or more and 10% or less of the radius of the fine particle 1. The height of the microprojections 2 (the dimension from the main surface of the microparticles 1 to the tips of the microprojections 2) is preferably less than 0.5% of the diameter of the microparticles 1. Moreover, it is preferable that the height of the microprotrusion 2 is 0.05 nm or more and less than 50 nm.

  Since a large number of such fine microprojections 2 are present on the surface of the fine particle body 1, when the crimping portion 16 of the crimping terminal 12 is crimped to the conductor portion 13 of the electric wire 11, the non-conductive coating is formed at the tip of the microprojection 2. It becomes easy to destroy. Further, the shape and size of each fine particle body 1 mixed and dispersed in the buffer layer 21 is controlled to be uniform as a whole. For this reason, the pressure applied when the crimping part 16 is crimped to the conductor part 13 acts uniformly on each fine particle body 1.

  The fine particle body 1 is more than a non-conductive film (for example, a natural oxide film, a corrosion-preventing film, or a contaminated film attached when forming an electric wire) formed on the surface of the conductor portion 13 (hereinafter also referred to as “conductor surface”). Consists of a metal with high hardness. The “hardness” described in the present specification may be defined by any of Vickers hardness, Brinell hardness, Rockwell hardness, and Shore hardness. In this embodiment, the conductor part 13 is comprised with Al or Al alloy. In this case, the fine particle body 1 is made of a metal or alloy containing at least one of Zn (zinc), Cr (chromium), Fe (iron), Co (cobalt), Ni (nickel), and Sn (tin). Can be configured. Further, by forming the fine particle body 1 with a metal, the fine particle body 1 itself is a conductive particle. However, the metal constituting the fine particle body 1 is not limited to those listed here, and for example, even if it is a compound that is intended to improve the function while further increasing the hardness and corrosion resistance by adding P. Good. Alternatively, Ni fine particles 1 containing inevitable impurity elements or P may be used.

  The fine particle body 1 can be configured to have a layer structure as shown in the cross-sectional views of FIGS. 3 (a) and 3 (b), for example. The fine particle body 1 shown in FIG. 3A has a layer structure (multilayer structure) including a core 31 and a coating layer 32 that covers the core 31. The core 31 is made of, for example, pure Ni, or made of Ni containing inevitable impurity elements or P. Pure Ni refers to a metal having a Ni content of 99% by mass or more. The covering layer 32 is constituted by, for example, a Ni—P layer. The covering layer 32 may be constituted by a Ni—P layer in which the composition ratio of Ni and P is inclined in the thickness direction of the covering layer 32. The thickness direction of the coating layer 32 means the radial direction of the fine particle 1, that is, the direction from the center of the core 31 toward the surface of the fine particle 1 when the fine particle 1 is formed in a spherical shape. In this case, the composition ratio of Ni and P may be inclined stepwise or continuously.

  Alternatively, the core 31 may be made of Ni containing P, and the core 31 may be covered with the Au coating layer 32 to form the fine particle body 1. Alternatively, the core 31 may be made of Cu, and the core 31 may be covered with a coating layer 32 made of Ni—P to form the fine particle body 1. Further, the core 31 is made of Cu, and the covering layer 32 covering the core 31 is made of Sn—Ag (silver) —Cu alloy, Sn—Ag alloy, Sn—Bi (bismuth) alloy, Au—Sn alloy. Any of these alloys or a metal containing at least one element of Au, Sn, Ag, and Pd may be used.

  In the fine particle body 1 shown in FIG. 3B, the outermost surface portion of the fine particle body 1 is constituted by the coating layer 32, and the inside is a multilayer structure 33. The multilayer structure 33 has a structure in which different types of metal layers (thin films) are alternately stacked on the outer side (in the direction in which the diameter increases) from the central portion 33a of the fine particle body 1. For example, the multilayer structure 33 is configured by alternately laminating Ni layers and Au layers from the central portion 33a toward the outside. In that case, an intermediate layer (interface layer) may exist between the Ni layer and the Au layer.

  It is also possible to configure the multilayer structure 33 by using the layer of the center portion 33a as a core layer and alternately laminating different kinds of metal layers outside the core layer. In that case, for example, each part can be made of the following materials. That is, the core layer is made of Ni or Ni—P, the coating layer 32 is made of Au, and the outer layer of the core layer is a structure in which Ni—Au alloys and Ni—P—Au alloys are alternately laminated. Is possible. In addition, the core layer is made of Cu, the coating layer 32 is made of Ni or Ni—P, and the outer layer of the core layer is made of Ni—Cu alloy and Ni—Cu—P alloy. An alternately stacked structure can be used.

4A to 4D are views for explaining another structure of the fine particle body according to the embodiment of the present invention.
The illustrated fine particle body 1 is electrically similar to the fine particle body 1 shown in FIGS. 2 and 3 in that it has electrical conductivity, but structurally (in terms of shape) is an alternative to the fractal structure. It has a polyhedral structure. That is, as a specific example of the polyhedral structure, the fine particle body 1 shown in FIG. 4A is a tetrahedral structure, the fine particle body 1 shown in FIG. 4B is a hexahedral structure, and the fine particle body 1 shown in FIG. Is a dodecahedron structure, and the fine particle body 1 shown in FIG. 4D has a icosahedron structure. In addition, when the microparticles | fine-particles body 1 is made into a polyhedron structure, the shape of each surface of the polyhedron does not necessarily need to be the same shape, and may be a polyhedron structure constituted by planes of different shapes.

  When the polyhedron 1 having a polyhedral structure is employed, local stress during caulking can be alleviated with respect to the conductor portion 13 and the crimp terminal 12 having physical properties that have a remarkable creep phenomenon. Thereby, the nonuniform deformation | transformation of the conductor part 13 can be suppressed and the stable connection performance can be hold | maintained.

  Further, the fine particle body according to the present invention is not limited to a structure constituted by a plane polygon, but a spherical structure or an elliptical sphere structure constituted by only a curved surface, or a cylindrical structure or cone constituted by a plane and a curved surface. It may be a body (needle-like) structure or a fullerene structure. The fine particles may be composed of carbon nanotubes. Furthermore, the fine particles of each structure may have a multilayer structure or a hollow structure. When the fine particle body has a hollow structure, the hollow portion of the fine particle body may be in a gas-sealed state or a vacuum state. Further, the fine particle body 1 having the fractal structure shown in FIGS. 2 and 3 may employ a hollow structure without the core 31. In particular, when a fine particle body having a hollow structure is employed, the fine particle body can be finely pulverized simultaneously with crimping of the crimp terminal (application of pressure). For this reason, further miniaturization of the fine particles that break the non-conductive coating can be realized. Therefore, it is possible to ensure fine and dense conduction between the conductor portion 13 of the electric wire 11 and the crimp portion 16 of the crimp terminal 12. As a result, it becomes possible to contribute to further stabilization of the electrical connection state in the electric wire 10 with a terminal.

(Element composition of fine particles)
Here, the elemental composition of the fine particle body 1 will be described.
The fine particle body 1 according to the present embodiment is preferably composed of a metal or alloy composed of an element showing an ionization tendency between the element of the conductor portion 13 and the element of the crimp terminal 12 (crimp portion 16). Further, the fine particle 1 is composed of an element having a standard oxidation-reduction potential E (V) between a hydrated ion and a single metal in an aqueous solution in a range of −1.7 (V) to 0.4 (V). It is preferable that the metal or alloy is used.

  Specifically, for example, as shown in Table 1 below, when the conductor portion 13 is made of Al and the crimp terminal 12 is made of Cu, an element showing an ionization tendency between Al and Cu, that is, Zn, Cr, It is preferable that the fine particle body 1 is composed of a single element of Fe, Co, Ni, or Sn, or a metal or alloy containing at least two of them. If the fine particle body 1 having such an element composition is applied, a substance composed of an element showing an intermediate ionization tendency between the constituent elements of the conductor portion 13 and the constituent elements of the crimp terminal 12 is converted into the conductor portion 13 and the crimp terminal 12. Will be inserted between. For this reason, when the crimp terminal 12 is crimped to the conductor portion 13, the fine particle 1 is present in the connection (contact) portion between the two, and the corrosiveness to moisture is reduced by the fine particle 1. Therefore, the corrosion resistance against moisture can be improved, and the durability and reliability in a humid environment can be increased.

(Physical properties of fine particles)
Next, the physical properties of the fine particles will be described.
The fine particle body 1 according to the present embodiment has a structure (hereinafter also referred to as “atomic level structure”) when viewed at the atomic level, which is any one of a single crystal structure, a polycrystalline structure, and an amorphous structure. The structure, or at least two or more of these structures coexist (coexist). Thus, by changing and mixing the atomic level structure of the fine particle 1, the mechanical strength (hardness), electrical conductivity (contact resistance), and the like of the fine particle 1 can be controlled according to the application.

  The fine particle body 1 has magnetism. In that case, the fine particles 1 may be composed of one element selected from Fe, Co, and Ni or an alloy containing at least two elements among 3d transition metal elements having a relatively large magnetic moment. preferable. Furthermore, the magnetism of the fine particle 1 may be strengthened by adding one kind of rare earth elements or at least two kinds of elements to the main constituent material of the fine particle 1. Advantages obtained when the fine particles 1 are magnetized will be described later.

<Method of manufacturing crimp terminal>
The method of manufacturing the crimp terminal 12 according to the present embodiment includes a step of bending a flat plate member (with the connection portion 15 already formed) serving as a material of the crimp terminal 12 into a predetermined shape by forging, and the crimp portion 16. And a step of forming the buffer layer 21 on the inner surface. Either of these two steps may be performed first. In the step of forming the buffer layer 21, as described above, the buffer layer 21 is formed by mixing and dispersing the conductive fine particles 1 having the fractal structure having the fine protrusions 2 on the surface. The buffer layer 21 is formed of a resin, plating, or grease having a waterproof and anticorrosive action on the conductor portion 13 and the crimping portion 16. A specific method for forming the buffer layer 21 will be described later.

<Method for manufacturing electric wire with terminal>
Next, a method for manufacturing a terminal-attached electric wire using the crimp terminal 12 obtained by the above-described crimp terminal manufacturing method will be described.

  In the embodiment of the present invention, before the crimp part 16 of the crimp terminal 12 is crimped to the conductor part 13 of the electric wire 11, the buffer layer 21 in which the fine particles 1 are mixed and dispersed by the above-described crimp terminal manufacturing method. Is previously formed on the inner surface of the crimping portion 16. Thereby, while preparing the crimp terminal 12 in which the buffer layer 21 was formed, the electric wire 11 which peeled the edge part of the coating | coated part 14 and exposed the conductor part 13 is prepared.

  Next, as shown in FIGS. 1A to 1C, the conductor portion 13 of the electric wire 11 is disposed on the crimp portion 16 of the crimp terminal 12, and the end portion of the covering portion 14 of the electric wire 11 is connected to the crimp terminal 12. It is arranged in the gripping part 17. Then, by crimping the crimp terminal 12 in this state, the crimp portion 16 of the crimp terminal 12 is crimped to the conductor portion 13 of the electric wire 11, and the grip portion 17 of the crimp terminal 12 is attached to the covering portion 14 of the electric wire 11. . At this time, the gripping part 17 grips the covering part 14 so as to sandwich the electric wire 11 from both sides.

  By crimping the crimping portion 16 to the conductor portion 13 as described above, a terminal-attached electric wire having the following configuration is obtained. That is, the contact interface between the conductor portion 13 and the crimping portion 16 is in a state in which the buffer layer 21 formed by mixing and dispersing the conductive fine particles 1 having the fractal structure with the fine protrusions 2 on the surface is interposed. . Further, the fine particle body 1 in the buffer layer 21 is in a state of being in contact with the conductor portion 13 by breaking through the non-conductive film existing on the surface of the conductor portion 13.

  Further, as shown in FIG. 5A, when the crimping portion 16 is crimped to the conductor portion 13 composed of the plurality of strands 13 a by caulking, the fine particle body 1 in the buffer layer 21 is strongly against the conductor portion 13. Pressed. Therefore, even if a nonconductive film exists on the surface of the conductor portion 13 (elementary wire 13a), each fine particle body can be obtained by dispersing fine particles 1 harder than the nonconductive film in the buffer layer 21. 1 breaks through (breaks) the non-conductive coating, and evenly and finely bites into the base portion of the conductor portion 13. Therefore, the crimping part 16 of the crimping terminal 12 can be brought into reliable and dense contact with the base of the conductor part 13 through the fine particle body 1 of the buffer layer 21.

  Further, in the crimp terminal 12 in which the buffer layer 21 is formed, the pressure due to caulking is greater than the conventional smooth surface sphere or the irregular fine particle body whose structure is not controlled. 16 is not dispersed at the contact interface between the conductor part 13 and the fine and dense minute protrusions 2 existing on the surface of the fine particle body 1 more intensively. For this reason, the pressure at the time of caulking works with high efficiency on the surface of the non-conductive coating as a load of shear fracture. Therefore, it becomes easy to break through the nonconductive film covering the surface of the conductor portion 13. As a result, a good contact state can be obtained over a wide area of the inner surface of the crimping portion 16 as compared with a conventional spherical fine particle or a fine particle whose structure is not controlled. For this reason, it is possible to stably maintain a connection state that is electrically low in contact resistance and mechanically good for a long period of time. Moreover, when providing serrations (concave / convex patterns) on the inner surface of the crimp terminal as in the past, it is necessary to produce a wide variety of molding dies according to the target product, and to maintain and manage these molding dies. However, according to this embodiment, it becomes unnecessary. For this reason, it becomes possible to improve the throughput of a manufacturing process.

  Incidentally, in the state before the crimping shown in FIG. 1C, the crimping portion 16 is formed in a substantially U shape by the pair of side wall portions 18 and the lower wall portion 19. On the other hand, in the state after the crimping shown in FIG. 5A, the two end portions (16a) of the crimping portion 16 bite in a state of being bent toward the conductor portion 13, and the biting protrusion (16a) ) To the left and right side wall portions, and further to the lower wall portion, the conductor portion 13 is covered with a curved surface in which the crimp portion 16 is continuous. For this reason, the conductor part 13 is surrounded by the buffer layer 21 over the entire circumference. However, the shape of the crimping portion 16 after crimping (caulking) is not limited to this, and for example, as shown in FIG. 5B, the two end portions (16a) of the crimping portion 16 are curved toward the conductor portion 13 side. It may bite in a state, and the conductor portion 13 may be covered with a curved surface from the protruding end portion (16a) of the bite to the upper ends of the left and right side wall portions, and a flat surface below that (side wall portion and lower wall portion).

  In addition, as a structure of a crimp terminal, the structure provided only with the connection part and the crimping | compression-bonding part other than the structure provided with the connection part 15, the crimping | compression-bonding part 16, and the holding part 17 mentioned above may be sufficient. This will be specifically described below with reference to FIG.

  6A and 6B are diagrams illustrating the configuration of the crimp terminal and the terminal-attached electric wire according to the embodiment of the present invention. FIG. 6A is an exploded perspective view showing a state before crimping, and FIG. It is a perspective view which shows the state which carried out, (c) is AA 'sectional drawing in (b).

  In this case, the method for manufacturing the crimp terminal includes at least a step of forming the buffer layer 21 on the inner surface (inner circumferential surface) of the crimp portion 16 formed in a cylindrical shape. In the step of forming the buffer layer 21 on the inner surface of the crimping portion 16, for example, grease (compound) in which the conductive fine particles 1 are blended is applied over the entire circumference of the inner surface of the crimping portion 16. Thereby, the crimp terminal 12 with the buffer layer 21 is obtained.

  Next, the crimp terminal 12 obtained by the above manufacturing method is attached to the conductor portion 13 of the electric wire 11. At this time, the conductor portion 13 of the electric wire 11 is inserted into the cylinder of the crimp portion 16 of the crimp terminal 12. Then, as shown in FIG. 6C, the entire circumference of the conductor portion 13 is surrounded by the buffer layer 21. By crimping the crimp terminal 12 in this state, the crimp part 16 of the crimp terminal 12 is crimped to the conductor part 13 of the electric wire 11. Thereby, the electric wire with a terminal is obtained.

  When the crimping portion 16 of the crimp terminal 12 is formed in a cylindrical shape and the buffer layer 21 is formed on the inner surface thereof, the crimping portion 16 after crimping (after crimping), for example, as shown in FIG. The cross-sectional shape can be a hexagon. However, the cross-sectional shape of the crimping part 16 after crimping may be a polygon other than a hexagon, an ellipse or a circle, or a combination of a curved surface and a plane. Further, when crimping the tubular crimping part 16, it is not limited to crimping (compressing) all parts of the outer surface of the crimping part 16, but a part of the outer surface of the crimping part 16 extends in the length direction of the electric wire 11. The surface of the conductor portion 13 may be compressed according to the uneven state.

  When the above configuration is adopted, the buffer layer 21 is disposed around the circumference (entire circumference) of the side surface of the conductor portion 13 exposed from the covering portion 14, and the conductor portion 13 is formed by the fine particles 1 existing in the buffer layer 21. The non-conductive coating on the surface can be destroyed. For this reason, the conductor part 13 and the crimping | compression-bonding part 16 can be electrically connected over the perimeter. Therefore, the electric wire 11 and the crimp terminal 12 can be connected with a sufficiently low contact resistance. Furthermore, the fine particle body 1 can be made to bite into the substrate of the conductor portion 13 over the entire circumference of the conductor portion 13. For this reason, it becomes possible to maintain the mechanical connection strength of the electric wire 11 and the crimp terminal 12 equally in the whole area of the circumferential direction, and to realize a stable connection state independent of the direction.

  Here, the buffer layer 21 is formed on the inner surface of the crimping part 16 by applying grease (compound fine particle blended) to the inner surface of the crimping part 16 of the crimping terminal 12. The buffer layer 21 may be formed on the surface of the conductor portion 13 by applying the same grease to the exposed surface (outer peripheral surface) of the conductor portion 13.

  Here, the buffer layer 21 is formed in advance on the inner surface of the crimping portion 16 of the crimp terminal 12. However, the present invention is not limited to this, and the buffer layer is formed in a predetermined shape (sheet, sleeve, It is also possible to form a cap shape. Hereinafter, the manufacturing method of the electric wire with a terminal will be described separately for each shape of the buffer layer.

(When the buffer layer is formed into a sheet)
FIG. 7 is a diagram for explaining a method of manufacturing a terminal-attached electric wire when the buffer layer is formed into a sheet shape, where (a) is an exploded perspective view showing a state before crimping, and (b) is a buffer layer on the conductor portion. 2 is a perspective view showing a state in which a crimp terminal is attached to an electric wire, and FIG. 3D is a cross-sectional view taken along line AA ′ in FIG.

  In this case, the method of manufacturing the electric wire with terminal includes a first step of forming a buffer layer 22 formed by mixing and dispersing conductive fine particles having a fractal structure with fine protrusions on the surface into a sheet shape, And a second step in which the crimping portion 16 is crimped to the conductor portion 13 in a state where the buffer layer 22 obtained in one step is attached to the conductor portion 13.

  In the first step, a sheet-like buffer layer 22 as shown in FIG. The buffer layer 22 is formed in a rectangular shape in plan view with a uniform thickness. The buffer layer 22 is formed flat. However, the buffer layer 22 has a property (flexibility) that is easily bent in shape.

  The buffer layer 22 can be formed by the following method, for example, when a resin is used as a constituent material of a layer serving as a base of the buffer layer 22. First, a large number of the fine particles 1 shown in FIG. 2, FIG. 3, or FIG. 4 are mixed in a liquid or paste-like resin material (binder), and each fine particle 1 is evenly dispersed in the resin material. Next, the resin material is formed into a large sheet, and then cut into individual pieces according to a desired size and shape. Thereby, the sheet-like buffer layer 22 is obtained.

  In the second step, first, as shown in FIG. 7B, the buffer layer 22 is wound around the conductor portion 13 of the electric wire 11 by winding the sheet-like buffer layer 22 obtained in the first step. Attach to. At this time, the end portions of the buffer layer 22 may be overlapped with each other as shown in FIG. 7D so that no gap is generated between the winding start end and the winding end end of the buffer layer 22.

  Next, as shown in FIG. 7 (c), the conductor portion 13 with the buffer layer 22 mounted thereon is disposed on the crimp portion 16 of the crimp terminal 12, and the covering portion 14 of the wire 11 is held by the grip portion of the crimp terminal 12. 17. Then, by crimping the crimp terminal 12 in this state, the crimp portion 16 of the crimp terminal 12 is crimped to the conductor portion 13 of the electric wire 11, and the grip portion 17 of the crimp terminal 12 is attached to the covering portion 14 of the electric wire 11. . Thereby, the electric wire 10 with a terminal is obtained.

  When the above manufacturing method is adopted, a special additional process such as forming the buffer layer 21 by plating or the like on the crimp terminal 12 becomes unnecessary, and a conventional general crimp terminal can be used as it is. Moreover, since it is sufficient to wind the sheet-like buffer layer 22 directly around the conductor portion 13, an increase in manufacturing cost can be suppressed.

(When the buffer layer is formed in a sleeve shape)
FIG. 8 is a diagram for explaining a method of manufacturing a terminal-attached electric wire when the buffer layer is formed in a sleeve shape, wherein (a) is an exploded perspective view showing a state before crimping, and (b) is a buffer layer on the conductor portion. 2 is a perspective view showing a state in which a crimp terminal is attached to an electric wire, and FIG. 3D is a cross-sectional view taken along line AA ′ in FIG.

  In this case, the method of manufacturing the electric wire with terminal includes a first step of forming a buffer layer 23 in a sleeve shape by mixing and dispersing conductive fine particles having a fractal structure with fine protrusions on the surface, and this first step. And a second step of crimping the crimping portion 16 to the conductor portion 13 in a state where the buffer layer 23 obtained in one step is attached to the conductor portion 13.

  In the first step, a sleeve-shaped buffer layer 23 as shown in FIG. The buffer layer 23 is formed in a cylindrical shape with a uniform thickness. The inside (inside the cylinder) of the buffer layer 23 becomes a through hole for inserting the conductor portion 13. And the entrance part of this through-hole becomes a circular opening part, and the other side is also a circular opening part. The inner diameter of the buffer layer 23 has a uniform dimension from one side to the other side in the central axis direction of the buffer layer 23. Further, the inner diameter of the buffer layer 23 is set slightly larger than the outer diameter of the conductor portion 13 of the electric wire 11.

  The buffer layer 23 can be formed by the following method, for example, when a resin is used as a constituent material of a layer serving as a base of the buffer layer 23. First, a large number of the fine particles 1 shown in FIG. 2, FIG. 3, or FIG. 4 are mixed in a liquid or paste-like resin material, and each fine particle 1 is evenly dispersed in the resin material. Next, after molding the resin material into a cylindrical shape, the resin material is cut into individual pieces according to a desired dimension (length). Thereby, the sleeve-shaped buffer layer 23 is obtained.

  In the second step, first, as shown in FIG. 8B, the buffer layer 23 is placed in the conductor portion by fitting the sleeve-like buffer layer 23 obtained in the first step into the conductor portion 13 of the electric wire 11. Attach to 13. At this time, a lubricant or the like may be applied to the surface of the conductor portion 13 as necessary, and then the buffer layer 23 may be fitted into the conductor portion 13.

  Next, as shown in FIG. 8C, the conductor portion 13 with the buffer layer 23 attached is disposed on the crimp portion 16 of the crimp terminal 12, and the covering portion 14 of the electric wire 11 is held by the grip portion of the crimp terminal 12. 17. Then, by crimping the crimp terminal 12 in this state, the crimp portion 16 of the crimp terminal 12 is crimped to the conductor portion 13 of the electric wire 11 and the grip portion 17 of the crimp terminal 12 is crimped to the covering portion 14 of the electric wire 11. . Thereby, the electric wire 10 with a terminal is obtained.

  When the above manufacturing method is employed, the buffer layer 23 in which the fractal-structured fine particles 1 are mixed and dispersed can be arranged uniformly with almost no gap over the periphery (entire circumference) of the side surface of the conductor portion 13. For this reason, the pressure at the time of a crimping | compression-bonding can be applied to the crimping | compression-bonding part 16 equally. As a result, it is possible to reduce the frequency of occurrence of poor connection of the crimp terminal 12 and to manufacture (produce) a terminal-attached electric wire with a high yield.

(When the buffer layer is formed in a cap shape)
FIG. 9 is a diagram for explaining a method of manufacturing a terminal-attached electric wire when the buffer layer is formed in a cap shape, wherein (a) is an exploded perspective view showing a state before crimping, and (b) is a buffer layer on the conductor portion. 2 is a perspective view showing a state in which a crimp terminal is attached to an electric wire, and FIG. 3D is a cross-sectional view taken along line AA ′ in FIG.

  In this case, the method of manufacturing the electric wire with terminal includes a first step of forming a buffer layer 24 formed by mixing and dispersing conductive fine particles having a fractal structure with fine protrusions on the surface into a cap shape, A second step of crimping the crimping portion 16 to the conductor portion 13 in a state where the buffer layer 24 obtained in one step is attached to the conductor portion 13.

  In the first step, a cap-shaped buffer layer 24 as shown in FIG. 9A is prepared. The buffer layer 24 has a uniform thickness and a circular cross section. The buffer layer 24 has a cylindrical shape in which one of the buffer layers 24 in the central axis direction is closed and the other is opened. The inside (inside the cylinder) of the buffer layer 24 becomes a non-through hole for inserting the conductor portion 13. The entrance portion of the non-through hole is a circular opening. The inner diameter of the buffer layer 24 has a uniform dimension from one side to the other side in the central axis direction of the buffer layer 24. Further, the inner diameter of the buffer layer 24 is set slightly larger than the outer diameter of the conductor portion 13 of the electric wire 11.

  For example, when a resin is used as a constituent material of a layer serving as a base of the buffer layer 24, the buffer layer 24 can be formed by the following method. First, a large number of the fine particles 1 shown in FIG. 2, FIG. 3, or FIG. 4 are mixed in a liquid or paste-like resin material, and each fine particle 1 is evenly dispersed in the resin material. Next, the buffer layer 24 is obtained by molding the resin material into a cap shape.

  In the second step, first, as shown in FIG. 9B, the buffer layer 24 is formed into the conductor portion by fitting the cap-shaped buffer layer 24 obtained in the first step into the conductor portion 13 of the electric wire 11. Attach to 13. At this time, a lubricant or the like may be applied to the surface of the conductor portion 13 as necessary, and then the buffer layer 24 may be fitted into the conductor portion 13.

  Next, as shown in FIG. 9C, the conductor portion 13 with the buffer layer 24 attached is disposed on the crimp portion 16 of the crimp terminal 12, and the covering portion 14 of the electric wire 11 is held on the grip portion of the crimp terminal 12. 17. Then, by crimping the crimp terminal 12 in this state, the crimp portion 16 of the crimp terminal 12 is crimped to the conductor portion 13 of the electric wire 11, and the grip portion 17 of the crimp terminal 12 is attached to the covering portion 14 of the electric wire 11. . Thereby, the electric wire 10 with a terminal is obtained.

  When the above manufacturing method is adopted, the entire exposed portion of the conductor portion 13 exposed from the covering portion 14 including the tip surface of the conductor portion 13 can be covered with the cap-shaped buffer layer 24. As a result, the entire exposed portion including the tip end surface of the conductor portion 13 is covered (shielded) by the cap-shaped buffer layer 24, and the crimp portion 16 is crimped to the conductor portion 13 via the buffer layer 24 in this state. become. For this reason, penetration of moisture or the like into the conductor portion 13 is suppressed by the buffer layer 24. Therefore, the electrolytic corrosion of the conductor part 13 caused by moisture can be effectively prevented. In addition, the fine particle body 1 in the buffer layer 24 can be always disposed at a substantially constant position without a gap on the bonding surface of the conductor portion 13 with respect to the crimp portion 16 of the crimp terminal 12. As a result, it becomes possible to extend the life and improve the reliability in the actual operation of the electric wire with terminal. Furthermore, the operation of crimping the crimping part 16 to the conductor part 13 can be performed with good reproducibility, and mass production can be performed stably.

  By the way, when the buffer layer 23 formed in a sleeve shape is attached to the conductor part 13, if the dimensional difference between the inner diameter of the buffer layer 23 and the outer diameter of the conductor part 13 is small, the opening edge of the buffer layer 23 is formed on the conductor part 13. There is a risk that it will not fit smoothly, for example, by being caught on the end face, and the mounting operation cannot be performed efficiently. The same applies to the case where the buffer layer 24 formed in a cap shape is attached to the conductor portion 13. In such a case, it is preferable to adopt the following configuration.

  That is, when the sleeve-shaped buffer layer 23 is used, as shown in FIGS. 10A to 10C, when the buffer layer 23 is formed in a sleeve shape, it is cut into the opening on the inlet side of the buffer layer 23. 23a is formed. The “inlet side” described in this specification means a side that first accepts insertion of the conductor portion 13 when the buffer layer 23 is fitted into the conductor portion 13. The sleeve-like buffer layer 23 has one opening on each of the buffer layer 23 in the central axis direction and the other, but when the buffer layer 23 is attached to the conductor portion 13, the buffer layer 23 is first attached. One opening part of this is made to oppose the front-end | tip part of the conductor part 13. As shown in FIG. In this case, the one opening is an entrance-side opening, and the other opening is a back-side opening. A plurality of (six in the example) cut portions 23 a are provided at an equal angular pitch in the circumferential direction of the buffer layer 23. Each cut portion 23a is formed in a state in which the opening edge on the inlet side of the buffer layer 23 is partially cut out in a wedge shape. Each cut portion 23 a is cut in the central axis direction of the buffer layer 23.

  Thus, by providing the notch 23a in the opening on the inlet side of the buffer layer 23, the opening diameter on the inlet side of the buffer layer 23 can be increased in a pseudo manner. In other words, the opening diameter on the inlet side of the buffer layer 23 can be increased by the presence of the plurality of cut portions 23a. For this reason, even when the dimensional difference between the inner diameter of the buffer layer 23 and the outer diameter of the conductor portion 13 is small, the conductor portion 13 can be easily fitted (inserted) into the opening on the inlet side of the buffer layer 23. As a result, the work of attaching the buffer layer 23 to the conductor portion 13 can be efficiently performed, and high production throughput can be realized.

  Further, when the cap-shaped buffer layer 24 is used, as shown in FIGS. 11A to 11C, when the buffer layer 24 is formed in a cap shape, it is cut into the opening on the inlet side of the buffer layer 24. By providing 24a, the same effect as described above can be obtained.

  When the sleeve-shaped buffer layer 23 is used, as shown in FIGS. 12A to 12C, when the buffer layer 23 is formed in a sleeve shape, the inner diameter of the buffer layer 23 is the inlet side (FIG. 12). You may form so that it may become small gradually toward the back | inner side (left side of FIG.12 (b)) from the (right side of (b)). In that case, the opening diameter on the inlet side of the buffer layer 23 may be set larger than the outer diameter of the conductor portion 13, and the opening diameter on the back side may be set equal to the outer diameter of the conductor portion 13.

  When the inner diameter of the sleeve-shaped buffer layer 23 is set as described above, the opening on the inlet side of the buffer layer 23 is in a state of opening larger than the outer diameter of the conductor portion 13 inserted into the opening. . For this reason, without applying a lubricant or the like on the surface of the conductor part 13, the conductor part 13 can be quickly inserted to the back side of the buffer layer 23 while reducing friction between the buffer layer 23 and the conductor part 13. Can do. Therefore, it is possible to improve the efficiency (throughput) of the mounting process of the buffer layer 23 without depending on the experience of the operator or the precise control of the assembly automatic machine.

  Moreover, when using the cap-shaped buffer layer 24, as shown to Fig.13 (a)-(c), when forming the buffer layer 24 in a cap shape, the internal diameter of the buffer layer 24 is a back | inner side from the entrance side. The effect similar to the above can be obtained by forming the film so as to gradually become smaller.

  By the way, the particle size of the fine particles to be blended in the buffer layer is determined depending on the state of the electric wire 11 provided with the conductor portion 13, specifically, the occurrence of contamination or roughening of the conductor surface during wire drawing or long-term exposure, or the conductor. It is desirable to change according to the type of material (hardness etc.) of the substrate. For example, when force is applied with the same load during caulking, when the non-conductive coating on the conductor surface is thick or the conductive substrate is soft, the fine-particle It is desirable to increase the particle size. Specifically, for example, as shown in FIG. 14, large-diameter fine particles 1 having a fractal structure with fine protrusions on the surface are mixed and dispersed in a buffer layer 21, and the conductor portion is interposed through the buffer layer 21. 13 and the crimping part 16 are preferably connected by crimping. In FIG. 14A, a buffer layer 21 in which a plurality (large number) of large particle bodies 1 having a large particle diameter are mixed and dispersed is formed on the pressure-bonding portion 16. In FIG. 14B, the conductor portion 13 is disposed on the crimping portion 16 with the buffer layer 21 interposed. In FIG. 14 (c), pressure due to caulking is applied to the crimping part 16 and the conductor part 13 from the direction of arrow F, and by applying the pressure, the fine particle body 1 having a large particle size in the buffer layer 21 is crimped. It is in a state where it bites into both the portion 16 and the conductor portion 13. In this case, since the fine particle body 1 having a large particle size is blended in the buffer layer 21, even if a thick nonconductive film is formed on the surface of the conductor portion 13, the nonconductive film is formed into a large particle particle body. 1 and the conductor part 13 and the crimping | compression-bonding part 16 can be connected reliably.

  On the other hand, when connection with the conductor part 13 is required in a region where the in-plane area of the crimping part 16 is small, the number of pinning by the fine particle body (connection part penetrated by destruction of the non-conductor coating) is increased, and the conductor In order to securely connect the portion 13 and the crimping portion 16, it is desirable to reduce the particle size of the fine particles and increase the number of fine particles per unit area of the buffer layer. Specifically, for example, as shown in FIG. 15, small-diameter fine particles 1 having a fractal structure with fine protrusions on the surface are mixed and dispersed in a buffer layer 21, and the conductor portion is interposed through the buffer layer 21. 13 and the crimping part 16 are preferably connected by crimping. In FIG. 15A, a buffer layer 21 in which a plurality (small number) of small particle bodies 1 having a small particle diameter are mixed and dispersed is formed on the pressure-bonding portion 16. In FIG. 15B, the conductor portion 13 is disposed on the pressure-bonding portion 16 via the buffer layer 21. And in FIG.15 (c), the pressure by crimping is applied to the crimping | compression-bonding part 16 and the conductor part 13 from the F arrow direction, and the small particle diameter microparticles | fine-particles body 1 in the buffer layer 21 are crimped | bonded by the application of the pressure. It is in a state where it bites into both the portion 16 and the conductor portion 13. In this case, since the microparticles 1 having a small particle diameter are blended in the buffer layer 21, even when connection in a region where the in-plane area of the crimping portion 16 is small is required, the buffer layer 21 has a small particle diameter. The fine particles 1 can be arranged at a high density to secure a desired number of pinning.

(Particle arrangement in the buffer layer)
Next, the arrangement of fine particles mixed and dispersed in the buffer layer will be described.

  FIG. 16 shows a case where fine particles are arranged vertically in the buffer layer. That is, in FIG. 16A, the fine particles 1 having a fractal structure with fine protrusions on the surface are mixed and dispersed in the buffer layer 21, and the fine particles 1 are vertically (buffer layer 21) in the buffer layer 21. (Thickness direction) are stacked (arranged in columns). In FIG. 16B, the conductor portion 13 is disposed on the pressure-bonding portion 16 via the buffer layer 21. In FIG. 16 (c), pressure due to caulking is applied to the crimping part 16 and the conductor part 13 from the direction of arrow F, and the fine particles 1 in the buffer layer 21 are applied to the crimping part 16 and the conductor by applying the pressure. It is in a state of biting into both parts 13. In this case, a plurality (two in the illustrated example) of fine particle bodies 1 are arranged in tandem in the buffer layer 21, and these fine particle bodies 1 are in contact with (adhering to) each other by pressure due to caulking. Further, in the thickness direction of the buffer layer 21, one (lower) fine particle body 1 bites into the crimping portion 16, and the other (upper) fine particle body 1 bites into the conductor portion 13.

  Here, in order to arrange the microparticles 1 in tandem in the buffer layer 21, it is desirable that the microparticles 1 be made of a magnetic material in order to impart magnetism to the microparticles 1. Specifically, when a resin binder is used as the material constituting the base layer of the buffer layer 21, the magnetic fine particles 1 are mixed and dispersed in the binder, and then a magnetic field is applied. By doing so, it becomes possible to arrange the microparticles 1 in tandem. The application of the magnetic field is performed, for example, by placing a jig for generating a desired magnetic pattern close to the buffer layer 21 before solidification (liquid state) in which the magnetic fine particles 1 are mixed. At this time, when the magnet is brought close to the iron sand scattered on the paper, the fine particles 1 in the binder are collected on the magnetic pattern generated by the jig in the same manner as the iron iron is collected near the magnet. For this reason, the magnetic pattern generated by the jig is transferred to the buffer layer 21. Further, the fine particles 1 are arranged in a stacked state on the magnetic pattern. Therefore, the fine particles 1 can be arranged in a column in the magnetic pattern generated by the jig and thus in the buffer layer 21.

  In addition, since the fine particles 1 are arranged in the buffer layer 21 according to the magnetic pattern, the arrangement of the fine particles 1 in the buffer layer 21 is not only the thickness direction of the buffer layer 21 but also the surface direction of the buffer layer 21. It is also possible to control even in the direction perpendicular to the thickness direction of the buffer layer 21. Specifically, for example, as shown in FIG. 17A, a jig 41 that generates a magnetic pattern 40 is disposed close to the buffer layer 21 before solidification via a thin plate-like support base 42. At this time, the buffer layer 21 and the magnetic pattern 40 are disposed in a state of being separated from each other by a certain distance due to the support 42. Further, a magnetic force due to the magnetic pattern 40 acts on the fine particle 1 mixed in the buffer layer 21, and the fine particle 1 is arranged immediately above the magnetic pattern 40 by being attracted by this magnetic force. For this reason, the arrangement of the fine particles 1 in the surface direction of the buffer layer 21 is a transfer of the arrangement of the magnetic pattern 40. Therefore, the fine particles 1 can be arranged in the surface direction of the buffer layer 21 in accordance with the arrangement of the magnetic patterns 40. Further, the fine particle body 1 attracted by the magnetic force of the magnetic pattern 40 becomes magnetized by the action of the magnetic force. For this reason, when the microparticles 1 are newly added from above, the newly added microparticles are collected on the magnetic microparticles. For this reason, the fine particles 1 can be stacked and arranged in the thickness direction of the buffer layer 21.

  Further, by changing the magnetic pattern 40 generated by the jig 41, it is possible to produce the buffer layer 21 in which the fine particles 1 are arranged in various arrangement patterns. Specifically, for example, the buffer layer 21 in which the fine particles 1 are arranged in the arrangement pattern shown in FIG. 17B or the arrangement pattern shown in FIG. Incidentally, in FIGS. 17B and 17C, the plurality of fine particle bodies 1 are arranged in a predetermined arrangement in the plane of the buffer layer 21. That is, in FIG. 17 (b), a plurality of (one in the illustrated example) five fine particle bodies 1 arranged adjacent to each other in the plane of the buffer layer 21 are arranged in a plurality of rows at a predetermined interval. Pattern. On the other hand, in FIG. 17C, in the plane of the buffer layer 21, a long row composed of a plurality (two in the illustrated example) of fine particles 1 and a smaller number (one in the illustrated example). ) And a short row of fine particles 1 are mixed and arranged.

  After the microparticles 1 are arranged in a desired pattern in the surface direction and the thickness direction of the buffer layer 21 in this way, the resin binder is cured (thermosetting, etc.) while maintaining the arrangement state, thereby obtaining a desired shape. The buffer layer 21 in which the fine particles 1 are arranged in a pattern can be produced. In addition, the sheet-like buffer layer 22, the sleeve-like buffer layer 23, and the cap-like buffer layer 24 described above can be produced by the same method. In addition, when the buffer layer 21 is formed by directly applying a liquid paste (such as grease) mixed with the fine particles 1 to the inner surface of the pressure-bonding portion 16, the outer surface of the pressure-bonding portion 16 on the opposite side of the liquid paste application surface is formed. The fine particles 1 can be arranged in a desired pattern arrangement by arranging the jigs for generating a magnetic pattern close to each other.

  In this way, the pattern forming method for realizing the desired pattern arrangement using the magnetism of the fine particle body 1 is similar to the case where serrations (uneven pattern) are formed on the inner surface of the crimp terminal. This makes it possible to reinforce mechanical and electrical connections. In addition, the magnetic pattern generating jig 41 in place of the molding die for serration formation is placed close to the buffer layer (21 to 24) before solidification, so that the pattern arrangement of the magnetic pattern 40 is changed to the buffer layer 21. Can be transferred. For this reason, it is possible to avoid the problem that the molding die for serration formation is worn by repeated press processing as in the prior art, and the fine particles 1 can be arranged in a desired pattern arrangement in the buffer layer stably over a long period of time. .

  Further, as described above, the fine particle body 1 is made magnetic, and by using this magnetism, the arrangement of the fine particle bodies 1 in the buffer layer 21 is controlled, so that the buffer layer is made of resin, plating, or grease on the inner surface of the crimping portion 16. When forming the sheet 21 or forming the sheet-like buffer layer 22, the sleeve-like buffer layer 23, or the cap-like buffer layer 24, various magnetic patterns are generated using magnets. Accordingly, the microparticles 1 can be arranged in a desired (arbitrary) pattern on the buffer layers (21 to 24). For this reason, it is not necessary to produce various types of molds and to manage the molds necessary for conventional serration formation. Therefore, the throughput of the manufacturing process can be greatly improved.

  In addition, when mixing and dispersing the conductive fine particle body 1 having a fractal structure with the fine protrusions 2 on the surface in the buffer layer 21, as shown in FIGS. 18A and 18B, the first fine particle body You may mix two types of fine particle bodies, such as 1a and the 2nd fine particle body 1b. The second fine particle body 1b is different from the first fine particle body 1a in at least one of composition, structure and physical properties. As a result, even when the desired connection performance cannot be maintained with only one type of fine particle body 1, it is possible to maintain the desired connection performance by mixing the two types of fine particle bodies 1a and 1b.

  For example, when it is necessary to keep the contact resistance low while keeping the electrolytic corrosion of the crimp terminal 12 at a certain level (allowing), the first fine particle body 1a of Cu and the second fine particle body 1b of Ni exhibiting low resistance are used. It is desirable to mix and disperse two types of fine particles in the buffer layer 21. In this case, if all the fine particle bodies 1 are made of Cu, deterioration due to electrolytic corrosion becomes remarkable at the portion where Cu and Al are in direct contact, but by replacing a part of the fine particle body 1 with Ni, the entire crimp terminal 12 It is possible to achieve a low resistance while suppressing electric corrosion.

  In addition, if the hardness of the nonconductive film covering the surface of the conductor portion 13 is higher than that of the first fine particle body 1a, a second material such as silica, alumina, zirconia, or the like having higher hardness than the nonconductive film or the first fine particle body 1a. It is desirable to mix and disperse the fine particles 1b in the buffer layer 21 together with the first fine particles 1a. In this case, if all of the fine particles 1 are composed of the first fine particles 1a, the nonconductive film may not be sufficiently destroyed. However, the nonconductive film can be reliably formed by mixing the second fine particles 1b having high hardness. The first fine particle body 1a can be brought into contact with the base portion of the conductor portion 13 that is broken and exposed. Moreover, in order to make the conductor part 13 and the 1st fine particle body 1a contact more reliably, as shown in FIG.18 (c), it is a conductor in the direction (left-right direction of a figure) orthogonal to the pressurization direction F by crimping. The part 13 and the crimping part 16 may be reciprocated relatively (including movement by vibration). This relative movement can be realized, for example, by moving at least one of the conductor portion 13 and the crimping portion 16 in the direction of the central axis of the electric wire 11 or rotating around the central axis of the electric wire 11 during caulking. By this relative movement, the conductor portion 13 and the crimping portion 16 slide with the fine particles (1a, 1b) in the buffer layer 21 interposed therebetween. For this reason, the location where the non-conductive coating film is broken by the second fine particle body 1b is expanded over a wide range by the above-described relative movement, and the first fine particle body 1a is brought into pressure contact with the substrate portion of the conductor portion 13 at the broken position to ensure conduction. be able to.

  Here, two kinds of the fine particles 1 mixed in the buffer layer 21 are used. However, the present invention is not limited to this, and fine particles having three or more different compositions, structures, physical and chemical properties are used. The buffer layer may be formed by blending and dispersing.

(Preparation method of fine particles)
Next, a method for producing a fine particle body will be described. Here, a method for producing a Ni—P metal fine particle (hereinafter also referred to as “Ni—P fine particle”) containing Ni as a main element will be described as an example.

(First manufacturing method)
First, nickel sulfate hexahydrate is dissolved in pure water to prepare a metal salt aqueous solution 15 dm ³ . In addition, sodium hydroxide is added to a solution in which sodium acetate is dissolved in pure water to a concentration of 1.0 kmol / m ³ to prepare a pH adjusting aqueous solution 15 dm ³ . The metal salt aqueous solution thus prepared and the pH adjusted aqueous solution are mixed with stirring to prepare a mixed aqueous solution 30 dm ³ having a pH of 7.3. The mixed aqueous solution is heated by an external heater while bubbling with N ₂ , Ar gas, or the like, and stirring is continued while maintaining the liquid temperature at 343K. Next, a reducing agent aqueous solution 15 dm ^{3 in} which sodium phosphinate is dissolved at a concentration of 1.8 kmol / m ³ in pure water is prepared, and the liquid temperature is similarly heated to 343 K by an external heater. The mixed aqueous solution (30 dm ³ ) and the reducing agent aqueous solution (15 dm ³ ) are mixed in a state where the liquid temperature is controlled in the range of 342K to 344K (343K ± 1K), and the mixture is processed by an electroless reduction method.
Thereby, it is possible to produce a powder of an aggregate of fine particles each having a fine protrusion on the surface and having a fractal structure containing Ni and P.

(Second production method)
First, nickel sulfate hexahydrate is dissolved in pure water to prepare a metal salt aqueous solution 15 dm ³ . In addition, sodium hydroxide is added to a solution in which sodium acetate is dissolved in pure water to a concentration of 1.0 kmol / m ³ to prepare a pH adjusting aqueous solution 15 dm ³ . The metal salt aqueous solution thus prepared and the pH adjusted aqueous solution are mixed with stirring to prepare a mixed aqueous solution 30 dm ³ having a pH of 7.3. The mixed aqueous solution is heated by an external heater while bubbling with N ₂ , Ar gas, or the like, and stirring is continued while maintaining the liquid temperature at 363K. Next, a reducing agent aqueous solution 15 dm ^{3 in} which sodium phosphinate is dissolved at a concentration of 1.8 kmol / m ³ in pure water is prepared, and the liquid temperature is similarly heated to 363 K by an external heater. Then, the mixed aqueous solution (30 dm ³ ) and the reducing agent aqueous solution (15 dm ³ ) are mixed in a state where the liquid temperature is controlled in the range of 362K to 364K (363K ± 1K), and processed by an electroless reduction method.
Thereby, it is possible to produce a powder of an aggregate of fine particles each having a fine protrusion on the surface and having a fractal structure containing Ni and P. In addition, it is possible to produce a fine particle body in which the height of the fine protrusion is controlled to be higher than that of the fine particle body obtained by the first production method.

(Third production method)
First, nickel sulfate hexahydrate and copper sulfate pentahydrate prepared so that the molar ratio of Ni and Cu is smaller than Ni / Cu = 239 are dissolved in pure water, and a metal salt aqueous solution 15 dm ³ Is made. Here, copper sulfate pentahydrate is given as an example of a substance that acts as a catalyst poison, and is not limited to the copper sulfate pentahydrate described above, and suppresses a rapid reduction reaction, Any hydrate having catalytic poisoning performance capable of precisely controlling the structure of the fine particles may be used. In addition, sodium hydroxide is added to a solution in which sodium acetate is dissolved in pure water to a concentration of 1.0 kmol / m ³ to prepare a pH adjusting aqueous solution 15 dm ³ . The metal salt aqueous solution thus prepared and the pH adjusted aqueous solution are mixed with stirring to prepare a mixed aqueous solution 30 dm ³ having a pH of 7.3. The mixed aqueous solution is heated by an external heater while bubbling with N ₂ , Ar gas, or the like, and stirring is continued while maintaining the liquid temperature at 363K. Next, a reducing agent aqueous solution 15 dm ^{3 in} which sodium phosphinate is dissolved at a concentration of 1.8 kmol / m ³ in pure water is prepared, and the liquid temperature is similarly heated to 363 K by an external heater. Then, the mixed aqueous solution (30 dm ³ ) and the reducing agent aqueous solution (15 dm ³ ) are mixed in a state where the liquid temperature is controlled in the range of 362K to 364K (363K ± 1K), and processed by an electroless reduction method.
Thereby, it is possible to produce a powder of an aggregate of fine particles each having a fine protrusion on the surface and having a fractal structure containing Ni and P. Further, compared with the fine particle body obtained by the first production method and the fine particle body obtained by the second production method, the height of the fine protrusion and the tip curvature radius of the fine protrusion are respectively the first production method. A fine particle body precisely controlled so as to be between the method and the second production method (intermediate size) can be produced.

  In the above-described manufacturing method, in order to obtain a desired fine particle body having a microprojection on the surface and having a fractal structure containing Ni and P, an ordinary optical microscope, SEM (scanning) is used. Electron microscope), TEM (Transmission Electron Microscope), AFM (Atomic Force Microscope) etc. and statistical analysis with the image obtained, and analyze the average particle size and distribution state by X-ray small angle scattering method, The optimum conditions for stably producing the fine particles were established.

(Production method of resin film in which fine particles are blended and dispersed)
Next, a method for producing a resin film in which fine particles are blended and dispersed will be described. The resin film production method described here is applied when the buffer layer is formed of resin, or when the above-described buffer layer having a sheet shape, sleeve shape, cap shape, or the like is formed of resin. is there.
As a resin film that is a binder in which fine particles of a fractal structure having fine protrusions of the present invention are mixed and dispersed, a thermoplastic resin generally used for an insulating adhesive or the like, or a thermosetting resin that is cured by heat treatment, Alternatively, a photocurable resin that is cured by light irradiation is desirable. Further, as the environment resistant material, a curable resin having excellent heat resistance and moisture resistance after connection between the electric wire and the crimp terminal is appropriate. In particular, among curable resins, epoxy adhesives (epoxy resins) can be cured in a short time, and therefore work efficiency in the manufacturing process is good. Furthermore, since the epoxy adhesive has a high adhesive performance due to the molecular structure forming the epoxy adhesive, it is possible to manufacture a highly reliable electric wire with a terminal.
The general epoxy resin used here is, for example, a polymer type epoxy resin (phenoxy resin) or at least one of urethane, polyester, and nitrile butadiene rubber (NBR) with respect to the main component epoxy. There are mixed resins, and there are systems in which various modifiers such as latent curing agents and coupling agents, catalysts, and the like are added for further modification. A solid or liquid epoxy resin may be used as a starting material.

  Here, an epoxy resin film that is generally effective is shown for the binder, but a resin other than an epoxy resin may be used as long as it has high adhesion performance, curing performance, and the like. For example, a binder in which a phenolic resin, an acrylic resin, or the like is mixed may be used.

Moreover, there exists the following method as an example of the method of mix | blending and disperse | distributing microparticles | fine-particles in a resin film.
First, at least one kind of liquid resin and an organic solvent such as acetone are weighed to desired values among epoxy resin, phenol resin, acrylic resin and the like used as a binder. Thereafter, the weighed liquid resin and the organic solvent are mixed using a quartz glass tube. Next, for example, a predetermined amount of Ni-P fine particle powder having a fractal structure provided with fine protrusions obtained by the above-described manufacturing method is put into a liquid mixture of the liquid resin and the organic solvent and mixed. . Next, after the powder of the fine particles is uniformly dispersed in the mixed liquid, the resin material obtained thereby is waited for a predetermined time, and finally is thinned to a desired thickness by a rolling roll. By the above method, a resin film in which fine particles are mixed and dispersed can be obtained. In the case where the buffer layer is formed on the inner surface of the crimping portion of the crimp terminal by using a resin, a resin material in which the fine particle powder described above is uniformly dispersed in the mixed solution may be applied to the inner surface of the crimping portion.

(Production method of plating layer in which fine particles are blended and dispersed)
Next, a method for producing a plating layer in which fine particles are blended and dispersed will be described. The method for producing a plating layer described here is applied when a buffer layer is formed by plating. As an example, electroplating having a positive electrode and a negative electrode is used.

  First, a Ni-P fine particle body having a fractal structure having minute protrusions is put into a desired plating solution. Then, the Ni—P fine particles in a colloidal particle state are made to reach the negative electrode surface using an external force such as stirring and rocking in a plating bath in which the fine particles are mixed, and are physically adsorbed there. . If the relationship of the Langmuir type monomolecular adsorption isotherm is established between the concentration of the colloidal Ni—P fine particles in the plating solution and the concentration of the dispersed Ni—P particles in the metal plating layer, the concentration exceeds a certain level. Then, the amount of adsorption becomes constant.

  Further, in order to increase the number of fine particles to be mixed and dispersed in the plating layer to a desired number, the acidity / basicity (pH) of the plating solution is appropriately controlled to fix the solid particles between the fine particles and the plating solution. The exchange of protons at the liquid interface is induced to charge the colloidal microparticles to an appropriate state as positive charges. As a result, a desired number of fine particles can be adsorbed to the negative electrode surface by electrostatic interaction due to Coulomb force based on electrophoresis. However, depending on the form (structure and size) of the individual fine particles, heteroaggregation may occur between the fine particles and the negative electrode, and the dispersion in the plating layer may become non-uniform. For this reason, the Ni—P fine particles to be introduced into the plating solution are controlled so that the ratio of the number of particles and the ratio of the particle diameters do not become extremely uneven. For example, the particle size ratio of the individual fine particles is desirably in the range of 10:10 to 10: 5.

  Thereafter, the Ni—P fine particles adsorbed on the negative electrode surface are included by the metal deposited in the periphery, and are taken into the plating layer. Here, when a part of the fractal-structure Ni-P fine particles having fine protrusions is hydrophobic, it is preferable to add a surfactant in order to disperse the fine particles in the best state. However, since rehydrophobization is required at the time of eutectoid, it is necessary to desorb or inactivate the surfactant during eutectoid. In fact, it is possible to inactivate the surfactant by cathodic reduction during plating, have a certain molecular weight that is relatively stable as a material, and have a azobenzene group that is considered to be relatively easy to synthesize. It is preferable to use a surfactant having a group (cationic surfactant) because the fine particles can be efficiently co-deposited on the plating film. The surfactant used in the production method is not limited to the above-mentioned azobenzene-modified cationic surfactant, but may be any surfactant that can be removed or inactivated during eutectoid.

(Preparation of grease (compound) in which fine particles are mixed and dispersed)
Next, a method for producing grease (compound) in which fine particles are blended and dispersed will be described. The grease manufacturing method described here is applied when a buffer layer is formed of grease.
In general, as the grease (compound) agent applied to the inner surface of the crimping portion of the crimp terminal or the surface of the conductor portion of the electric wire, it is desirable to use a silicone composition material that has a low degree of deterioration and excellent weather resistance even when exposed to harsh environments. . However, since the silicone grease itself does not have conductivity, when the buffer layer is formed only with the grease, low resistance cannot be realized at the connection portion between the electric wire and the crimp terminal. For this reason, when forming a buffer layer with grease, it is necessary to add the electroconductive fine particle body which has a fractal structure provided with said microprotrusion. This fine particle is an additive for imparting conductivity to at least the buffer layer among the additives for adding various functions. For blending and kneading the conductive fine particles, which are additives that add various functions, heat treatment mixing or vacuum mixing may be used depending on the effectiveness or importance of each application. In addition to the fine particles, for example, an antioxidant, a flame retardant, a heat-resistant additive, a pigment, a foaming agent, a crosslinking agent, a curing agent, a vulcanizing agent, or a release agent may be added. Furthermore, depending on the situation and purpose, silica, alumina, zirconia, mica, clay, zinc carbonate, zinc oxide, glass beads, polydimethylsiloxane, polymethylsilsesquioxane, alkenyl group-bonded polysiloxane compounds, etc. can be added simultaneously. May be. For the kneading of the additive containing fine particles and grease, for example, a closed kneader is used, and a single or multiple roll or a colloid mill device is used to uniformly disperse the fine particles in the grease. Let Thereby, the grease which mix | blended and disperse | distributed microparticles | fine-particles is obtained. If this grease is applied to the inner surface of the crimping portion or the surface of the conductor portion, a buffer layer can be formed on the applied surface. Further, after forming this buffer layer on the inner surface of the crimping portion or the surface of the conductor portion, they are crimped by caulking and subjected to a predetermined heat treatment or the like, whereby a good electrical property is provided between the crimping portion and the conductor portion. It is possible to realize a terminal-attached electric wire with excellent weather resistance, in which both the connection portions are reinforced while maintaining conductivity.

Next, one optimum requirement for carrying out the present invention will be described.
First, when the conductor portion 13 of the electric wire 11 is made of Al (or Al alloy) and the crimp terminal 12 is made of Cu (or Cu alloy), the optimum condition of the fine particles 1 to be dispersed and blended in the buffer layer is as follows: First, the fine particle body 1 is made of Ni—P metal, second, the fine particle body 1 has a fractal structure, and third, the tip curvature radius of the microprojection 2 of the fine particle body 1 is 0.03 nm. The above can be mentioned. The grounds are as follows.

  First, Ni which is the main element of the Ni—P metal fine particle 1 has an ionization tendency between Al which is a constituent material of the conductor portion 13 and Cu which is a constituent material of the crimp terminal 12. For this reason, compared with the state where Al and Cu are in direct contact, the progress of electrolytic corrosion can be reduced. Therefore, it is possible to improve the reliability and extend the life as a terminal-attached electric wire. Further, Ni that is the main element of the fine particle body 1 has a higher hardness than Cu that is a constituent material of the crimp terminal 12. For this reason, compared with the case where the non-conductive coating on the surface of the conductor portion is pierced with a crimp terminal in which serrations (concavo-convex pattern) are formed, the Ni-P fine particle body having minute protrusions efficiently destroys the non-conductive coating, Reliable conduction can be ensured.

  Furthermore, since Ni which is the main element of the fine particle body 1 is an element exhibiting strong magnetism, it can function as an electromagnetic shield that shields the leakage magnetic field from the conductor portion of the electric wire by dispersing this throughout the buffer layer. Can do. For this reason, it is possible to reduce electromagnetic noise generated when the electric wire is energized and to suppress malfunction of peripheral devices. Further, in the case of a fractal structure including multiple microprojections, it is possible to break through the non-conductive coating on the electric wire conductor with a low load force compared to a sphere. In addition, since the diameter of the fine particle body 1 is on the order of μm, if the tip curvature radius of the fine particle body is on the order of nm, the area that contacts the wire conductor during caulking becomes very small. For this reason, the pressure at the time of the load which acts on the contact part of a fine particle body and an electric wire conductor becomes the sixth power of about 10, and destruction of a nonconductor film can be easily caused by low load. As a result, a reliable electrical connection state can be ensured between the crimp terminal 12 and the conductor portion 13, and the contact resistance between them can be reduced. In addition, since a large number of fine protrusions are present on the surface of the fine particle body, more fine protrusions than the number of fine particle bodies mixed and dispersed in the buffer layer can be bitten into the electric wire conductor. For this reason, in the connection (contact) part of the crimp terminal 12 and the conductor part 13, it becomes possible to suppress the looseness by a creep phenomenon and to ensure the mechanical connection strength of the whole said connection part firmly.

<Modifications>
The technical scope of the present invention is not limited to the above-described embodiments, but includes forms to which various changes and improvements are added within the scope of deriving specific effects obtained by constituent elements of the invention and combinations thereof.

  For example, in the above embodiment, conductive metal particles are used as the fine particles to be mixed and dispersed in the buffer layer. However, the present invention is not limited to this, and the hardness is higher than that of metal but lower than that of insulator. Even if the fine particles are made of diamond-like carbon (DLC), which is a material, the nonconductive film on the surface of the electric wire conductor can be broken.

  Further, the fine particle body 1 to be mixed and dispersed in the buffer layer (21 to 24) is provided with a large number of fine protrusions 2 on the surface, but the structure of the fine particle body 1 is minute on the surface of the fine protrusions 2. A plurality of second minute protrusions (not shown) smaller than the protrusions 2 may be provided. The following effects can be obtained by adopting a configuration in which the surface of the microprojection 2 is provided with a second microprojection smaller than this. That is, when the conductor portion 13 is a stranded wire composed of a plurality of extra fine wires, there is a possibility that a region (part) where the nonconductive film on the extra fine wire cannot be broken and penetrated by only the minute protrusions 2 remains during crimping. is there. On the other hand, when a fine particle having a fractal structure having a second microprojection smaller than this is applied to the surface of the microprojection 2, the nonconductive film breaks on the ultrafine wire and the presence of the second microprojection is present. Can be complemented with certainty. For this reason, it becomes possible to obtain a desired performance also about the intensity | strength and conduction | electrical_connection of the conductor part comprised with the ultrafine wire.

  In addition, with regard to waterproofness that suppresses deterioration due to electrolytic corrosion of the electric wire with terminal, the region excluding the terminal portion for external connection (connection portion 15) is bonded to a resin case (housing, etc.) or highly water-resistant. By covering with a material or the like and completely sealing, desired waterproofness can be ensured, and reliability of the electric wire with terminal and long life can be achieved.

  Moreover, the electric wire used for the electric wire with a terminal is not limited to an Al electric wire, and may be a Cu electric wire. When using Cu-based electric wires, if it is possible to reduce the thickness of the Cu-based electric wires while maintaining the desired performance, the total cost of the copper material can be reduced, and installation by reducing the weight of the electric wires Workability can be ensured.

  However, when an aluminum-based electric wire is used as the terminal-attached electric wire, the total weight and raw material costs in the wire and cable harness can be reduced as compared with the case where a copper-based electric wire is used. As a result, when an electric wire with a terminal is used for an automobile or the like, it is possible to manufacture a railway vehicle, automobile, ship, aircraft, etc. having a lighter body than the conventional one while maintaining the same performance as a conventional harness. . This makes it possible to construct a transportation system that reduces energy consumption during operation.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

(Appendix 1)
According to a first aspect of the invention,
While having a crimping part to be crimped to the conductor part of the electric wire,
Comprising a buffer layer formed on the surface of the crimping portion that contacts the conductor portion;
The buffer layer is formed of resin, plating or grease,
The buffer layer is provided with a crimp terminal in which conductive fine particles having a fractal structure with fine protrusions on the surface are mixed and dispersed.

(Appendix 2)
The crimp terminal according to appendix 1, preferably,
The fine particle body includes a second minute protrusion smaller than the minute protrusion on the surface of the minute protrusion.

(Appendix 3)
The crimp terminal according to appendix 1 or 2, preferably,
The tip curvature radius of the microprotrusion arranged on the surface of the fine particle body is 0.03 nm or more and 500 nm or less.

(Appendix 4)
The crimp terminal according to any one of appendices 1 to 3, preferably,
The tip curvature radius of the microprotrusion arranged on the surface of the fine particle body is 0.0006% or more and 10% or less of the radius of the fine particle body.

(Appendix 5)
The crimp terminal according to any one of appendices 1 to 4, preferably,
The height of the microprotrusions arranged on the surface of the fine particle body is less than 0.5% of the diameter of the fine particle body.

(Appendix 6)
The crimp terminal according to any one of appendices 1 to 5, preferably,
The height of the fine protrusions arranged on the surface of the fine particle body is 0.05 nm or more and less than 50 nm.

(Appendix 7)
The crimp terminal according to any one of appendices 1 to 6, preferably,
The fine particle body has a hardness higher than that of the nonconductive film formed on the surface of the conductor portion.

(Appendix 8)
The crimp terminal according to any one of appendices 1 to 7, preferably,
The fine particle body is formed of a metal or an alloy composed of an element that exhibits an ionization tendency between the element of the conductor portion and the element of the crimping portion.

(Appendix 9)
The crimp terminal according to any one of appendices 1 to 8, preferably,
The fine particle body is composed of a metal or alloy composed of an element having a standard oxidation-reduction potential between a hydrated ion and a single metal in an aqueous solution in a range of −1.7 V or more and 0.4 V or less.

(Appendix 10)
The crimp terminal according to any one of appendices 1 to 9, preferably,
The fine particles are made of a metal or alloy containing at least one of Zn, Cr, Fe, Co, Ni, and Sn.

(Appendix 11)
The crimp terminal according to any one of appendices 1 to 9, preferably,
The fine particles are made of Ni containing P.

(Appendix 12)
The crimp terminal according to any one of appendices 1 to 9, preferably,
The fine particles are made of Ni containing inevitable impurity elements.

(Appendix 13)
The crimp terminal according to any one of appendices 1 to 9, preferably,
The conductor portion is made of Al or Al alloy,
The crimp terminal is made of Cu or Cu alloy,
The fine particles are made of Ni containing P.

(Appendix 14)
The crimp terminal according to any one of appendices 1 to 9, preferably,
The fine particle body has a core and a coating layer covering the core.

(Appendix 15)
The crimp terminal according to appendix 14, preferably,
The core is made of Ni;
The said coating layer is comprised by the Ni-P layer.

(Appendix 16)
The crimp terminal according to appendix 15, preferably,
The coating layer is constituted by a Ni-P layer in which the composition ratio of Ni and P is inclined in the thickness direction of the coating layer.

(Appendix 17)
The crimp terminal according to appendix 14, preferably,
The core is made of Cu,
The said coating layer is comprised by the Ni-P layer.

(Appendix 18)
The crimp terminal according to appendix 14, preferably,
The core is made of Cu,
The coating layer is made of any one of Sn—Ag—Cu alloy, Sn—Ag alloy, Sn—Bi alloy, and Au—Sn alloy, or at least one element of Au, Sn, Ag, and Pd. It is comprised with the metal containing.

(Appendix 19)
The crimp terminal according to any one of appendices 1 to 18, preferably,
The fine particles have magnetism.

(Appendix 20)
The crimp terminal according to any one of appendices 1 to 19, preferably,
The microparticles are stacked in the thickness direction of the buffer layer.

(Appendix 21)
The crimp terminal according to any one of appendices 1 to 20, preferably,
The fine particles are arranged in a predetermined arrangement in the surface of the buffer layer.

(Appendix 22)
The crimp terminal according to any one of appendices 1 to 21, preferably,
The fine particle body includes a first fine particle body and a second fine particle body that is different from the first fine particle body in at least one of composition, structure, and physical properties.

(Appendix 23)
The crimp terminal according to any one of appendices 1 to 22, preferably,
The fine particles have a single crystal structure, a polycrystalline structure, an amorphous structure, or a mixture of at least two of them.

(Appendix 24)
The crimp terminal according to any one of appendices 1 to 23, preferably,
The fine particle body has a multilayer structure or a hollow structure.

(Appendix 25)
The crimp terminal according to any one of appendices 1 to 24, preferably,
The buffer layer is formed of a resin, plating, or grease having a waterproof and anticorrosive action on the conductor portion and the crimp portion.

(Appendix 26)
According to a second aspect of the invention,
While having a crimping part to be crimped to the conductor part of the electric wire,
Comprising a buffer layer formed on the surface of the crimping portion that contacts the conductor portion;
The buffer layer is provided with a crimp terminal in which conductive fine particles having a polyhedral structure are mixed and dispersed.

(Appendix 27)
According to a third aspect of the invention,
While having a crimping part to be crimped to the conductor part of the electric wire,
Comprising a buffer layer formed on the surface of the crimping portion that contacts the conductor portion;
The buffer layer is provided with a crimp terminal in which conductive fine particles having any one of a spherical structure, an elliptical spherical structure, a cylindrical structure, a conical structure, and a fullerene structure are mixed and dispersed. .

(Appendix 28)
According to a fourth aspect of the invention,
While having a crimping part to be crimped to the conductor part of the electric wire,
Comprising a buffer layer formed on the surface of the crimping portion that contacts the conductor portion;
The buffer layer is provided with a crimp terminal in which fine particles of carbon nanotubes are mixed and dispersed.
Incidentally, even in the crimp terminal described in the second to fourth aspects, it is possible to adopt the configurations of additional notes 2 to 25 within a range that does not hinder the combination in configuration.

(Appendix 29)
According to a fifth aspect of the present invention,
A crimping terminal having a crimping part to be crimped to a conductor part of an electric wire,
Production of a crimp terminal comprising a step of forming a buffer layer formed by mixing and dispersing conductive fine particles having a fractal structure with fine protrusions on the surface of the crimp portion on the side in contact with the conductor portion A method is provided.

(Appendix 30)
According to a sixth aspect of the present invention,
An electric wire with a terminal comprising: an electric wire having a conductor portion; and a crimp terminal having a crimp portion crimped to the conductor portion of the electric wire,
A buffer layer formed of resin, plating or grease is interposed at the contact interface between the conductor portion and the crimp portion,
In the buffer layer, conductive fine particles having a fractal structure with fine protrusions on the surface are mixed and dispersed,
The particulate matter in the buffer layer is provided with a terminal-attached electric wire that breaks through a non-conductive film existing on the surface of the conductor portion and is in contact with the conductor portion.

(Appendix 31)
The terminal-attached electric wire of appendix 30, preferably,
The buffer layer is formed of a resin, plating, or grease having a waterproof and anticorrosive action on the conductor portion and the crimp portion.

(Appendix 32)
According to a seventh aspect of the present invention,
An electric wire having a conductor part, and a crimp terminal having a crimp part crimped to the conductor part of the electric wire,
A first step of forming a buffer layer formed by mixing and dispersing conductive fine particles having a fractal structure with fine protrusions on the surface of the crimp portion on the side in contact with the conductor portion;
A second step of pressure-bonding the pressure-bonded portion on which the buffer layer is formed in the first step to the conductor portion;
The manufacturing method of the electric wire with a terminal containing is provided.

(Appendix 33)
According to an eighth aspect of the present invention,
An electric wire having a conductor part, and a crimp terminal having a crimp part crimped to the conductor part of the electric wire,
A first step of forming a buffer layer formed by mixing and dispersing conductive fine particles having a fractal structure with fine protrusions on the surface into a predetermined shape;
A second step of pressure-bonding the pressure-bonding portion to the conductor portion in a state where the buffer layer obtained by the first step is attached to the conductor portion;
The manufacturing method of the electric wire with a terminal containing is provided.

(Appendix 34)
A method for manufacturing a terminal-attached electric wire according to attachment 33, preferably,
In the first step, the magnetic fine particles are dispersed in a liquid binder, and the arrangement of the fine particles in the binder is controlled using a jig that generates a predetermined magnetic pattern.

(Appendix 35)
A method for manufacturing a terminal-attached electric wire according to attachment 33, preferably,
In the first step, the buffer layer is formed in a sheet shape,
In the second step, the sheet-like buffer layer is wound around the conductor portion and attached.

(Appendix 36)
A method for manufacturing a terminal-attached electric wire according to attachment 33, preferably,
In the first step, the buffer layer is formed in a sleeve shape or a cap shape,
In the second step, the sleeve-shaped or cap-shaped buffer layer is fitted into the conductor portion.

(Appendix 37)
A method for manufacturing a terminal-attached electric wire according to attachment 36, preferably,
In the first step, when the buffer layer is formed in a sleeve shape or a cap shape, a notch is provided in the opening on the inlet side of the buffer layer.

(Appendix 38)
A method for manufacturing a terminal-attached electric wire according to attachment 36, preferably,
In the first step, when the buffer layer is formed in a sleeve shape or a cap shape, the buffer layer is formed so that the inner diameter of the buffer layer decreases from the inlet side toward the back side.

DESCRIPTION OF SYMBOLS 1 ... Fine particle body 2 ... Minute protrusion 10 ... Electric wire with a terminal 11 ... Electric wire 12 ... Crimp terminal 13 ... Conductor part 14 ... Covering part 15 ... Connection part 16 ... Crimp part

Claims (6)

While having a crimping part to be crimped to the conductor part of the electric wire,
Comprising a buffer layer formed on the surface of the crimping portion that contacts the conductor portion;
The buffer layer is formed of resin, plating or grease,
A crimp terminal in which conductive fine particles having a fractal structure with fine protrusions on the surface are mixed and dispersed in the buffer layer. The crimp terminal according to claim 1, wherein the fine particle body is formed of a metal or an alloy composed of an element showing an ionization tendency between the element of the conductor portion and the element of the crimp portion. The crimp terminal according to claim 1, wherein the fine particle body is formed of a metal or an alloy containing at least one of Zn, Cr, Fe, Co, Ni, and Sn. The crimp terminal according to claim 1, wherein the fine particle body includes a core and a coating layer that covers the core. The crimp terminal according to claim 1, wherein the fine particle body has magnetism. An electric wire with a terminal comprising: an electric wire having a conductor portion; and a crimp terminal having a crimp portion crimped to the conductor portion of the electric wire,
A buffer layer formed of resin, plating or grease is interposed at the contact interface between the conductor portion and the crimp portion,
In the buffer layer, conductive fine particles having a fractal structure with fine protrusions on the surface are mixed and dispersed,
The fine particles in the buffer layer are in contact with the conductor portion by breaking through a non-conductive coating existing on the surface of the conductor portion.