Wire harness, method of connecting terminal and coated wire, and mold

Abstract

The height (F) of a protruding portion (7) is less than the thickness of a crimping portion (5) before crimping. If the height of the protruding portion (7) is greater than the thickness of the crimping portion, then a recess is prone to form in the inner surface of the crimping portion (5). In other words, because there is more metal flowing outwards, a recess corresponding to the metal flow is prone to form on the inner surface side. If such a recess does form, adhesion with a covered area (27) is likely to deteriorate. This is problematic because such a gap would be a path allowing the ingress of moisture. On the other hand, if the height of the protruding portion (7) is less than the thickness of the crimping portion (5) before crimping, then when the crimping portion (5) is compressed during crimping, the amount of metal flowing towards the protruding portion (7) diminishes, making it possible to suppress the formation of a receding portion on the inner surface of the crimping portion (5).

Claims

1. A wire harness comprising: a coated wire and a terminal that are connected with each other, wherein the terminal includes an approximately cylindrical crimping portion, in which the coated wire is crimped, and a terminal body; the crimping portion is formed of a plate-like material rolled up into a substantially cylindrical shape with edges of the plate-like material being welded together at a joining part; except for a part through which the coated wire is inserted, other parts of the crimping portion are closed; a protruding portion is formed along a longitudinal direction of the terminal on a periphery surface of the crimping portion that corresponds to a covered portion of the coated wire; and a protruding height of the protruding portion from a periphery surface of the crimping portion in a direction perpendicular to a compression direction of the crimping portion on a cross section in a diameter direction of the crimping portion is equal to or less than a body thickness of the crimping portion before crimping, wherein a level difference is formed between the protruding portion and the periphery surface of the crimping portion on the cross section in the diameter direction of the crimping portion; a surface perpendicular to the compression direction at the protruding portion is formed to the periphery of the protruding portion; a tilted portion or a smoothly connecting tilted portion is formed at a boundary part between the surface perpendicular to the compression direction of the crimping portion at a base part of the protruding portion and an arc surface of the periphery of the crimping portion; and the joining part and the protruding portion are formed at different positions in a circumferential direction on a periphery surface of the crimping portion.

2. The wire harness according to claim 1, wherein: the protruding portion is formed at a position that corresponds to a fitting section of a first mold and a second mold that are used for crimping.

3. A method of connecting a terminal and a coated wire wherein: the terminal includes a crimping portion, in which the coated wire is crimped, and a terminal body; the crimping portion is formed by rolling up a plate-like material into an approximately cylindrical shape, and joining and welding edges of the plate-like material at a joining part; and except for a part through which the coated wire is inserted, other parts of the crimping portion are closed, the method comprising: inserting the coated wire into the crimping portion; using a first mold and a second mold that face each other to press the crimping portion; fitting the first mold into an inner part of the second mold; crimping a covered portion of the coated wire at the crimping portion; and forming a protruding portion on the periphery surface of the crimping portion at a position corresponding to a fitting section of the first mold and the second mold, wherein a protruding height of the protruding portion from a periphery surface of the crimping portion in a direction perpendicular to a compression direction of the crimping portion on a cross section in a diameter direction of the crimping portion is equal to or less than a body thickness of the crimping portion before crimping; a tapered portion or a smoothly connecting tapered portion that is tilted inward to a direction perpendicular to the compression direction of the first mold and the second mold is provided at an end portion of the first mold; on the cross section in the diameter direction of the crimping portion, a level difference corresponding to the shape of the end portion of the first mold is formed on the protruding portion between the protruding portion and the periphery surface of the crimping portion; a surface perpendicular to the compression direction at the protruding portion is formed to the periphery of the protruding portion; a tilted portion or a smoothly connecting tilted portion is formed at a boundary part between the surface perpendicular to the compression direction of the crimping portion at a base part of the protruding portion and an arc surface of the periphery of the crimping portion; and the joining part and the protruding portion are formed at different positions in a circumferential direction on a periphery surface of the crimping portion.

4. A mold used for crimping a terminal and a coated wire comprising a first mold and a second mold that face each other, wherein: the first mold fits into an inner portion of the second mold so that it is possible to crimp a covered portion of the coated wire with the terminal; a tapered portion or a smoothly connecting tapered portion that is tilted inward to a direction perpendicular to a compression direction of the first mold and the second mold is provided at an end portion of the first mold; a protruding portion according to a shape of the end part of the first mold is formed along a longitudinal direction of the terminal on a periphery surface of a crimping portion of the terminal that corresponds to a covered portion of the coated wire; a level difference is formed between the protruding portion and the periphery surface of the crimping portion on the cross section in the diameter direction of the crimping portion; a surface perpendicular to the compression direction at the protruding portion is formed to the periphery of the protruding portion; and a tilted portion or a smoothly connecting tilted portion is formed at a boundary part between the surface perpendicular to the compression direction of the crimping portion at a base part of the protruding portion and an arc surface of the periphery of the crimping portion, wherein the level difference and a joining part of the terminal are formed at different positions in a circumferential direction on a periphery surface of the terminal.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a perspective view showing a wire harness 30.

(2) FIG. 2 is a perspective view showing a state in which a coated wire 23 is inserted into a terminal 1.

(3) FIG. 3 is a longitudinal section of FIG. 2.

(4) FIG. 4 is a cross section showing a state in which a crimping portion 5 is arranged between a mold 31a and a mold 31b.

(5) FIG. 5 is a cross section of the molds 31a and 31b of A-A line in FIG. 4.

(6) FIG. 6 is an enlarged view of the proximity of a fitting section when a crimping portion 5 is crimped by the molds 31a and 31b.

(7) FIG. 7 is an enlarged view of a protruding portion 7 formed on the crimping portion 5.

(8) FIG. 8 (a) is an overall view showing another mold 31b.

(9) FIG. 8 (b) is an enlargement view of the proximity of a tip portion of the mold 31b.

(10) FIG. 8 (c) is an enlargement view of the proximity of a tip portion of the mold 31b.

(11) FIG. 9 (a) is an enlargement view of the protruding portion 7 formed on the crimping portion 5 by the mold shown in FIG. 8 (b).

(12) FIG. 9 (b) is an enlargement view of the protruding portion 7 formed on the crimping portion 5 by the mold shown in FIG. 8 (c).

(13) FIG. 10 shows a method for evaluating a water cut-off performance of the wire harness 30.

DESCRIPTION OF SOME EMBODIMENTS

(14) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a wire harness 30. The wire harness 30 is formed by connecting a terminal 1 and a coated wire 23.

(15) The terminal 1 includes a terminal body 3 and a crimping portion 5 that are formed integrally. A male-type connector, which is not shown in the drawing, can be inserted into the terminal body 3 from a front-end portion 17 of its longitudinal direction. The terminal body 3 is equipped with an elastic contacting piece 15 that contacts with an insertion tab of the male-type connector.

(16) The crimping portion 5 is a closed type and formed in an approximately cylindrical shape. The crimping portion 5 is formed by rolling up a plate-like material into an approximately cylindrical shape and joining edges thereof each other at a joining part 21. Also, a sealed portion 11 is provided at the front-end portion of the crimping portion 5 (on the side of the terminal body 3). That is, the crimping portion 5 is sealed except for a rear-end portion 19 through which the coated wire 23 is inserted. The joint portion 21 and the sealed portion 11 are welded by laser welding and the like for example.

(17) The terminal 1 is formed by pressing using a plate-like member made of copper, for example. That is, every part of the terminal 1 before sealing and crimping has an approximately equal thickness. However, the thickness of the sealing portion 11 or the crimping portion 5 of the terminal 1 changes during sealing or crimping. Therefore, for example, in order to get the thickness of the terminal 1 before crimping from the wire harness 30, the thickness of one sheet of the material used for the terminal body 3 is to be measured.

(18) In the coated wire 23, an insulating covered area 27 coats wires 25. When the coated wire 23 is inserted into the crimping portion 5, a part of the covered area 27 at the tip of the coated wire 23 is removed to expose the wires 25. For the covered area 27, a material that is usually used in this technical field such as polyvinyl chloride (PVC), polyethylene, or the like can be chosen. Also, for the wires 25, aluminum or aluminum alloy can be applied, for example.

(19) On the periphery surface of the crimping portion 5, a protruding portion 7 is formed along a longitudinal direction thereof. The protruding portion 7 is formed during crimping the crimping portion 5. The protruding portion 7 will be described in detail later.

(20) Since the crimping portion 5 is crimped with the wires 25 and the covered area 27, the crimping portion 5 adheres with the covered area 27 so to seal the crimping portion 5. On this occasion, all parts of the crimping portion 5 except for the rear-end portion 19 are sealed to be watertight by the joint portion 21 and the sealing portion 11 so that moisture entering into the crimping portion 5 can be prevented.

(21) Next, a forming process of a wire harness will be described. FIG. 2 and FIG. 3 show a connecting process of the terminal 1 and the coated wire 23 where FIG. 2 is a perspective view and FIG. 3 is a longitudinal section. First, the coated wire 23 is inserted into the cylindrical crimping portion 5. As mentioned above, the covered area 27 at the tip part of the coated wire 23 is removed to expose the wires 25. Both the exposed part of the wires 25 and the covered portion of the covered area 27 are positioned inside the crimping portion 5.

(22) Next, the crimping portion 5 is compressed by the mold. FIG. 4 is a longitudinal partial section showing the state in which the crimping portion 5 is arranged between a mold 31a and a mold 31b. As shown in FIG. 4, the crimping portion 5 is arranged between a pair of molds 31a and 31b.

(23) FIG. 5 is a cross section of the molds 31a and 31b on a cross section of A-A line in FIG. 4. That is, FIG. 5 shows the shapes of the molds 31a and 31b at the part in which the covered area 27 is crimped. The mold 31b, which is the first mold, is an anvil mold and the mold 31a, which is the second mold, is a crimper mold. The molds 31a and 31b are arranged to face each other and at least one of the molds can move toward the direction so to approach each other (the direction shown by an arrow C in the drawing). The facing surfaces of the molds 31a and 31b are formed in arc shapes. The mold 31b is fitted into the mold 31a to form an approximately circular shape.

(24) FIG. 6 is an enlarged view of the proximity of B part in FIG. 5 when the crimping portion 5 is crimped. Since certain rigidity is required for the tip portion of the mold 31b (the proximity of the border with the inner circumference face of the mold 31a), the tip portion of the mold 31b cannot be sharpened completely and a measurable thickness is required. For this reason, when the molds 31a and 31b crimp the crimping portion 5 (and the coated wire 23), the protruding portion 7 corresponding to the thickness of the tip portion of the mold 31b is formed at the fitting section of the molds 31a and 31b. Since the protruding portion 7 is formed along the fitting section of the molds 31a and 31b, the protruding portion 7 is formed in a straight line along a longitudinal direction of the crimping portion 5 (two places).

(25) FIG. 7 is an enlarged view of the proximity of the obtained protruding portion 7 of the crimping portion 5. An upper part of the protruding portion 7 (a contacting part with the mold 31a) is formed in a smooth curve. Whereas a level difference 9 according to the shape of the tip portion of the mold 31b is formed at a lower part of the protruding portion 7 (a contacting part with the mold 31b).

(26) Here, the height of the protruding portion 7 (F in the drawing) is less than the thickness of the crimping portion 5 before crimping. If the height of the protruding portion 7 is greater with regard to the thickness of the crimping portion, a recess is likely to be formed on the inner surface of the crimping portion 5. That is, the amount of metal that flows outward (the protruding portion 7) increases, and, therefore, a recess according to the metal flow is likely to be formed on the inner surface side.

(27) If such a recess is formed, the adhesive property with the covered area 27 may be impaired. For example, when left in a high temperature environment or the like, the compression force given to the covered area 27 may be released and a minute gap may be formed between the recess portion and the covered area 27. Such a gap can serve as a path for moisture entry, which causes a problem.

(28) On the other hand, if the height of the protruding portion 7 is less than the thickness of the crimping portion 5 before crimping, the amount of metal that flows to the side of the protruding portion 7 diminishes when the crimping portion 5 is compressed during crimping and it is possible to suppress the formation of a recess portion on the inner surface of the crimping portion 5.

(29) The height of the protruding portion 7 is a height from a base part of the level difference 9 (the border part between the protruding portion 7 and the arc portion) to a top part of the protruding portion 7 when viewed from the direction (a vertical direction in the drawing shown by an arrow E) that is perpendicular to the crimping direction (a vertical direction in the drawing shown by an arrow D) of the molds 31a and 31b on the cross section. Also, the thickness of the crimping portion 5 before crimping can be obtained from, for example, the terminal body 3.

(30) Also, to decrease the height of the protruding portion 7, it is preferred to make the tip thickness of the end part of the mold 31b as thin as possible. That is, since the height of the protruding portion 7 is determined by the tip thickness of the end part of the mold 31b and the clearance of the molds 31a and 31b, the tip thickness of the mold 31b may be designed taking the rigidity of the mold 31b in consideration.

(31) According to the present embodiment, since the height of the protruding portion 7 is less than the thickness of the crimping portion 5 before crimping, it is possible to suppress the formation of a recess on the inner surface of the crimping portion 5. Therefore, it is possible to keep the adhesive property between the covered area 27 and the inner surface of the crimping portion 5 and a watertight property of the crimping portion 5 can be secured.

(32) The shape of the tip part of the mold 31b is not limited to the shape shown in FIG. 6 and the like. That is, the tip part of the mold 31b may be in forms other than the one shown in FIG. 6 in which the tip part of the mold 31 is formed only with a surface perpendicular to the crimping direction.

(33) For example, FIG. 8 (a) is an overall view showing another embodiment of the mold 31b and FIG. 8 (b) is an enlargement view of G part in FIG. 8 (a). As shown in FIG. 8 (b), a tapered portion 33, which tilts to the direction (an arrow E in the drawing) that is perpendicular to the crimping direction (an arrow D in the drawing) on the cross section, may be formed at the tip part of the mold 31b.

(34) Also, this tapered portion 33 may be formed, not in a straight line as shown in FIG. 8 (b), but in an arc shape as shown in FIG. 8 (c). That is, the tip part of the mold 31b is not formed only with a surface that is perpendicular to the crimping direction, but the tapered portion 33 may be formed at the boundary part between the surface perpendicular to the crimping direction and the arc surface, smoothly connecting the same.

(35) FIG. 9 (a) is a partial enlargement cross section of the proximity of the protruding portion 7 of the crimping portion 5 crimped by the mold shown in FIG. 8 (b). As shown in FIG. 9 (a), a tilted portion 13 that tilts linearly to the direction (an arrow E in the drawing) that is perpendicular to the crimping direction (an arrow D in the drawing) is formed at the level difference 9. The height of the protruding portion 7 (H in the drawing) is a height from a base part of the level difference 9 (the border part between the protruding portion 7 and the arc portion) to a top part of the protruding portion 7 when viewed from the direction (the direction of the arrow E) that is perpendicular to the crimping direction (the direction of the arrow D) of the molds 31a and 31b on the cross section.

(36) Similarly, FIG. 9 (b) is a partial enlargement cross section of the proximity of the protruding portion 7 of the crimping portion 5 crimped by the mold shown in FIG. 8 (c). As shown in FIG. 9 (b), a tilted portion 13 that tilts in an arc shape to the direction (an arrow E in the drawing) that is perpendicular to the crimping direction (an arrow D in the drawing) is formed at the level difference 9. The height of the protruding portion 7 (I in the drawing) is also a height from the base part of the level difference 9 (the border part between the protruding portion 7 and the arc portion) to the top part of the protruding portion 7 when viewed from the direction (the direction of the arrow E) that is perpendicular to the crimping direction (the direction of the arrow D) of the molds 31a and 31b on the cross section.

WORKING EXAMPLES

(37) Next, a wire harness according to the present invention and a wire harness for comparison are manufactured for experiments and the performance of each of the samples is tested. The tests will be described below.

(38) Air is supplied from the coated wire of the wire harness toward the terminal to test whether the air leaks out of the rear end part or not. FIG. 10 shows an outline of the method of the experiment. In the experiment, the terminal 1, which is crimped to the wire harness 30, is placed into a water tank 41 containing water and pressurized air is supplied from an end part of the wire harness 30 toward the terminal 1 by a regulator 42.

(39) (Wire Harness)

(40) For the base material of the terminal, a copper alloy material FAS-680 (made by Furukawa Electric Co., Ltd, Ni: 2.3 mass %, Si: 0.6 mass %, Sn: 0.15%, Zn: 0.5 mass %, Mg: 0.1 mass %, remainder: Cu and unavoidable impurities) having a thickness of 0.25 mm and a structure shown in FIG. 1 was used. For the electric wire, an aluminum alloy wire (wire diameter of 0.43 mm) was used. The composition of the core wire is Fe: 0.2 mass %, Cu: 0.2 mass %, Mg: 0.1 mass %, Si: 0.04 mass %, remainder: Al and unavoidable impurities. The diameter of the core wire is 2.1 mm, the outer diameter of the electric wire is 2.8 mm, and the length of the electric wire is 30 cm. Then, an end part of the electric wire, with exposed core wires, was inserted into the crimping portion of the crimping terminal to be crimped by the crimping device provided with the crimping mold shown in FIG. 5. The ratio of compression (the ratio of an area of cross section after crimping to an area of cross section before crimping) at this occasion was set to be 70%. In this way, a protruding portion (parting line) was formed at the part which is covered and crimped.

Working Examples 1, 2

(41) On this occasion, the height of the protruding portion of Example 1 and 2, which was varied by changing the thickness of the tip of the mold, was 0.1 mm and 0.2 mm respectively.

Comparative Example 3

(42) Comparative Example 3 is similar to Working Examples 1 and 2 except that the height of the protruding portion was set to be 0.3 mm by changing the thickness of the tip of the mold.

(43) Working Examples 1, 2 and Comparative Example 3 were named as Sample 1-3 and number of samples of each of the Samples n was five. The pressure of a maximum of 400 kPa was applied thereto and the one with no leaks at 400 kPa was marked as a success. The results are shown in Table 1.

(44) TABLE-US-00001 TABLE 1 Thickness before Protrusion height Success Rate of crimping after crimping the leak test 1 0.25 mm 0.1 mm 100% 2 0.25 mm 0.2 mm 100% 3 0.25 mm 0.3 mm  80%

(45) As shown in Table 1, the success rates of No. 1 and No. 2 having the protruding heights less than the thickness of the terminal before crimping were 100%. However, leak was found in No. 3 having the protruding height greater than the thickness of the terminal before crimping and its success rate was 80%.

(46) Also, although an electric wire having an outer diameter of 2.8 mm was used in the above working examples, it was similarly possible to suppress the formation of a recess portion on the inner surface of the crimping portion by making the protruding height less than the thickness of the terminal before crimping when electrical wires with different diameters were used. Particularly, if the protruding height was 2.0 mm or less, the success rate for the tests for water cut-off performance was 100%.

(47) Although the embodiments of the present invention have been described referring to the attached drawings, the technical scope of the present invention is not limited to the embodiments described above. It is obvious that persons skilled in the art can think out various examples of changes or modifications within the scope of the technical idea disclosed in the claims, and it will be understood that they naturally belong to the technical scope of the present invention.

(48) For example, although the cases in which aluminum electric wires were used for Working Examples are described, it is not limited thereto and copper may be used for the electric wires.

(49) Also, although two molds 31a and 31b are used to crimp and connect the terminal with the electric wire in the above embodiments, three or more molds may be used, for example. Similarly in such cases, the tip part of the mold requires a certain thickness since it is required to secure the certain rigidity. If such a mold is used, the protruding portion is formed along a longitudinal direction of the terminal and the protruded height of the protruding portion is preferably equal to or less than the thickness of the crimping portion before crimping.

(50) Also, it is possible to bundle a plurality of the wire harness according to the present invention. In the present invention, such a structure in which a plurality of wire harness are bundled together is called a wire harness structure.

DESCRIPTION OF NOTATIONS

(51) 1 . . . terminal 3 . . . terminal body 5 . . . crimping portion 7 . . . protruding portion 9 . . . level difference 11 . . . sealed portion 13 . . . tilted portion 15 . . . elastic contacting piece 17 . . . front-end portion 19 . . . rear-end portion 21 . . . joint portion 23 . . . coated wire 25 . . . wire 27 . . . covered portion 30 . . . wire harness 31a, 31b . . . mold 33 . . . tapered portion 41 . . . water tank 42 . . . regulator