Manufacturing process for electrical cables with terminals

Abstract

Manufacturing method for an electrical cable with a terminal, comprising: a step of connecting a plurality of core wires (12) by an ultrasonic bonding process to form a bonded core wire (13A); a step of arranging the connected core wire (13A) on a base bottom part (42) of a terminal (31) between a pair of crimping parts (43) extending from the bottom base part (42); a step of adjusting the clamp (31) on which the connected core wire (13A) is arranged on a support (52) of a crimping device (51) so that the base bottom part (42) is supported on a support surface (53) of the support (52) under the crimping device (55) of the crimping device (51); and a step of crimping the terminal (31) to the connected core wire (13A) by causing the counter support (52) and the crimping device (55) to come close to each other, and deforming the crimping parts (43) by a bulging groove (57) of the crimping device (55) until a space between the support surface (53) and the bulging groove (57) defines a predetermined crimped shape, wherein in the step of connecting the plurality of core wires (12), the core wires (12) are formed into the connected core wire (13A) having a rectangular cross-sectional shape with a width (X) and a height (Y) in a plane orthogonal to an axis of the connected core wire (13A), characterized in that the width (X) is not longer than a length obtained by subtracting twice a thickness (T) of the clamp (31) from a width (W) of the bulge groove (57) in a state in which the space defines the predetermined squeezed shape, wherein the height (Y) of the rectangular cross-sectional shape formed in the step of connecting the plurality of core wires (12) is orthogonal to the width (X) of the cross-sectional shape and not shorter than a length obtained by subtracting twice the thickness (T) of the clamp (31) from a maximum distance (H) between the bearing surface (53) and round arc surfaces (57a) of the bulging groove (57) in a state in which the space defines a predetermined crimped shape, wherein the bulging groove (57) has two round arc surfaces (57a) projecting in a direction separated from the support surface (53), extending in a longitudinal direction of the connected core wire (13A), and lined up in a width direction (Dw), and wherein, when a distance from an outer end of one of the two round arc surfaces (57a) to an outer end of the other of the two round arc surfaces (57a) in the width direction is a width (W) of the bulge groove (57), an inner distance between the pair of crimping pieces (43) extending in a vertical direction before the crimping step is larger than a value obtained by subtracting twice the thickness (T) of the clamp (31) from the width (W) of the bulge groove (57).

Description

[0001] The present invention relates to a manufacturing method for an electric cable with a terminal, in which a terminal is crimped to an electric cable having a core wire bundle with a plurality of bundled conductor core wires.

[0002] Typically, from the standpoint of increasing the allowable electric current of an electric cable and improving the bending strength, an electric cable is proposed that includes a core wire bundle (e.g., a twisted wire) with a plurality of bundled conductor core wires. When a terminal is crimped onto such a core wire bundle (the twisted wire), the conductor core wire located in an outer peripheral side of the core wire bundle directly contacts the terminal and is electrically connected to the terminal. However, the conductor core wire located in a central part of the core wire bundle is connected to the terminal through the conductor located in the outer peripheral part of the core wire bundle.Accordingly, in order to improve an overall electrical conductivity between the core wire bundle and the terminal, it is desirable that not only the electrical conductivity (the electrical conductivity of the outer peripheral part) between the conductor core wire and the terminal but also the electrical conductivity (the electrical conductivity of the middle part) between the conductor core wires is improved.

[0003] On the other hand, in recent years, aluminum and aluminum alloys can sometimes be used as a material of the conductor core wire because aluminum and aluminum alloy are lighter and lower in cost than copper. However, in this case, since the insulating property of an oxide layer (aluminum oxide) naturally formed on a surface of the conductor core wire is high, such an invention for improving the above-described electrical conductivity is particularly required. Specifically, it is necessary to improve the electrical conductivity of the outer peripheral part and the electrical conductivity of the central part of the core wire bundle.

[0004] For example, in one of the conventional manufacturing processes for an electric cable with a terminal (hereinafter referred to as a "conventional manufacturing process"), an ultrasonic bonding or welding process is applied to a core wire bundle (a twisted pair cable) formed with conductor core wires made of aluminum, so that oxide layers on the surfaces of the conductor core wires are destroyed, to connect the conductor core wires together and integrally form the core wire bundle into a single wire. Thus, both the conductor core wire located in the outer peripheral part of the core wire bundle and the conductor core wire located in the middle part essentially come into direct contact with the terminal.As a result, since the electrical conductivity of the middle part is further improved than in a case where the above-described single wire is not formed, the overall electrical conductivity between the core wire bundle and the terminal can be further improved (see, for example, Patent Literature 1).

[0005] [Patent literature 1] JP 2009 - 231 079 A

[0006] From DE 11 2009 001 147 T5 a manufacturing method for an electrical cable with a terminal is known, which has the features of the preamble of claim 1.

[0007] Further prior art is known from the documents DE 11 2010 002 631 T5, DE 11 2011 100 268 T5, DE 11 2011 101 263 T5 and US 2012 / 0 324 727 A1. SUMMARY OF THE INVENTION

[0008] The object of the present invention is to provide a manufacturing method for an electric cable having a terminal in which the terminal can be crimped to a connected core wire while maintaining a connected state of the connected core wire with a plurality of interconnected conductor core wires as much as possible.

[0009] According to one aspect of the invention, there is provided a manufacturing method for an electrical cable with a terminal, comprising the features of claim 1.

[0010] The plurality of conductor core wires may be made of at least aluminum or an aluminum alloy. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A to 1D are diagrams explaining an outline of a manufacturing method for an electric wire with a terminal according to an exemplary embodiment of the present invention. Fig. 1A to 1D are respective perspective views in an end part of the electrical cable. Fig. 2A to 2C are diagrams that explain the electrical cable to which the terminal is crimped. Fig. 2A is a front view of the end portion of the electrical cable. Fig. Figure 2B is a front view of the end portion of the electrical cable with a formed connected core wire. Fig. 2C a front view of the connected core wire. Fig. 3 is a schematic view of an ultrasonic bonding apparatus applying an ultrasonic bonding process to a core wire bundle. Fig. 4 is a perspective view of a terminal crimping device that compressively secures or welds the terminal to the electrical cable, and the electrical cable. Fig. 5A and Fig. 5B are diagrams explaining a method of fastening or welding the terminal under pressure by the terminal crimping device. Fig. 5A is a front view of the terminal crimping device in which the terminal and the connected core wire of the electric cable are arranged. Fig. 5B is a front view of a counter support on which the terminal and the connected core wire of the electric cable are arranged. Fig. 6 is a front view of the terminal crimping device under a state where the terminal is crimped to the electric wire. Fig. 7 is a sectional view of a connected or welded part of the electric cable with the terminal, where the terminal is crimped to the electric cable. DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

[0011] The bonding force generated by an ultrasonic bonding process is typically smaller than the bonding force generated by bonding methods other than ultrasonic bonding (e.g., welding or soldering). If an excessively large external force is applied to a core wire bundle (a bonded core wire) undergoing an ultrasonic bonding process, the conductor core wires may fail to maintain the bonded state. The core wire bundle may be separated into multiple conductor core wires, resulting in a bonded portion being destroyed, resulting in a single wire shape being lost. In this case, an oxide layer will again form on the surfaces of the separated conductor core wires, potentially damaging the above-described shape integration effect (the single wire shape).

[0012] When the terminal is crimped to the electric wire by a conventional manufacturing method, in a process that involves caulking the terminal to the core wire bundle, the ultrasonic bonding method is applied. The core wire bundle is pressed and deformed until the core wire bundle has a prescribed crimped shape, which is the shape after the crimping process is completed. From the standpoint of improving the overall electrical conductivity between the core wire bundle and the terminal, it is desirable to prevent the shape cancellation of the individual wire of the core wire bundle as much as possible during the pressing and deformation process.

[0013] With reference to the drawings, a manufacturing method for an electric cable with a terminal according to an embodiment of the present invention will be described below.

[0014] In the manufacturing method for an electric cable with a terminal according to the present embodiment, firstly according to Fig. 1A, an insulation sheath 14 of an electric cable 11 is peeled off to expose a core wire bundle 13 formed with a plurality of conductor core wires 12. Then, according to Fig. 1B, an ultrasonic bonding process (a detail will be described below) is applied to the core wire bundle 13 to form a bonded core wire 13A with the interconnected adjacent conductor core wires 12. Then, after the bonded core wire 13A is clamped to a prescribed position of the terminal 31 according to Fig. 1C is installed, the terminal 31 to the connected core wire 13A (and the insulation sheath 14 in the periphery thereof) according to Fig. 1D. This creates an electrical cable 1 with a terminal.

[0015] According to Fig. 1A and Fig. 2A, the electric wire 11 is formed such that an outer periphery of the core wire bundle 13 comprising the plurality of bundled conductor core wires 12 is covered with the insulation sheath 14. In the present example, the conductor core wire 12 is an uncoated element wire made of at least one of aluminum and an aluminum alloy. In other words, the electric wire 11 is at least one of an aluminum electric wire and an aluminum alloy electric wire.

[0016] According to Fig. 1B and Fig. 2B, the connected core wire 13A obtained by connecting the core wire bundle 13 of the electric wire 11 under the ultrasonic bonding process has a sectional shape orthogonal to an axis of the connected core wire 13A. The sectional shape may be a shape with a width and height orthogonal to each other. The sectional shape is a rectangular shape in the present embodiment, but may be any other shape with the width and height, such as an elongated shape. In the connected core wire 13A, the plurality of conductor core wires 12 constituting the core wire bundle 13 are connected to each other by ultrasonic vibration.

[0017] According to Fig. 3, an ultrasonic bonding device 20 that bonds the core wire bundle 13 of the electric wire 11 together through the ultrasonic bonding process includes a grinding stone 21, a support plate 22, a sliding claw 23, and a support plate 24. The grinding stone 21 causes ultrasonic oscillation back and forth on a plate surface of the drawing by an ultrasonic oscillator. On an upper surface of the grinding stone 21 (a surface that comes into contact with the core wire bundle), a roulette wheel (illustration is omitted) is formed, which has a plurality of protrusions extending in a direction intersecting a vibration direction at right angles to suppress sliding between the upper surface of the grinding stone 21 and the core wire bundle 13.In the ultrasonic bonding device 20, a cross-sectionally rectangular space defined by the grindstone 21, the abutment plate 22, the slide claw 23, and the abutment 24 is set as a forming space S. The conductor core wires 12 of the core wire bundle 13 arranged in the forming space S are bonded together by the ultrasonic bonding process.

[0018] The counter support plate 22 is arranged in a side part of the grindstone 21. The sliding claw 23 is arranged at a position opposite the counter support plate 22 on the upper surface of the grindstone 21. The sliding claw 23 can be moved so that it comes close to the counter support plate 22 or is separated from it. Fig. 3, the sliding claw 23 moves in a direction shown by an arrow mark A in the drawing to press the core wire bundle 13 in that direction.

[0019] The counter bearing 24 is arranged in an upper part of the grindstone 21 and the counter bearing plate 22 and is raised and lowered so that the counter bearing 24 can come close to the grindstone 24 or be separated from it. In Fig. 3, the counter bearing 24 moves in a direction shown by an arrow mark B in the drawing to press the core wire bundle 13 in this direction.

[0020] The ultrasonic bonding device 20 moves the slide claw 23 and the abutment 24 in the directions described above, so that the width and height of the forming space S can be freely changed. Therefore, the ultrasonic bonding device 20 is configured to change the width and height of the bonded core wire 13A.

[0021] According to Fig. 1C, the terminal 31 has an electrical connection part 32 and a crimping part 33. The terminal 31 is formed by press-working a metal plate formed of an electrically conductive metal material, such as copper or a copper alloy. Accordingly, in this exemplary embodiment, the thickness of the terminal 31 is substantially uniform at any position.

[0022] The electrical connecting part 32 has a flat, plate-shaped connecting plate part 34. A connecting hole 34a is formed in the connecting plate part 34. The connecting plate part 34 is electrically connected to a terminal base of a connecting device by, for example, inserting a fastening bolt into the connecting hole 34a.

[0023] The crimping part 33 has a conductor crimping part 41 and a sheath crimping part 45 in order from the electrical connection part 32 side. The conductor crimping part 41 includes a base bottom part 42 and a pair of conductor crimping parts 43 (crimping parts) formed in both side parts of the base bottom part 42. The connected core wire 13A is mounted on the base bottom part 42. The conductor crimping parts 43 extend from the base bottom part 42 to hold the connected core wire 13A between them. The conductor crimping part 41 deforms the one pair of conductor crimping parts 43 to be bent inward (caulked), so that the conductor crimping part 41 is crimped to the connected core wire 13A of the electric wire 11. Thus, the terminal 31 is electrically conductive and connected to the core wire bundle 13 of the electrical cable 11.

[0024] The sheath crimping member 45 includes a base bottom portion 46 and a pair of sheath crimping members 47 formed in both side portions of the base bottom portion 46. The base bottom portion 46 of the sheath crimping member 45 extends from the base bottom portion 42 of the conductor crimping member 41. The insulation sheath 14 of the electric wire 11 is mounted to the base bottom portion 46. The sheath crimping members 47 extend from the base bottom portion 46 to sandwich the insulation sheath 14 as part of the electric wire 11. The sheath crimping member 45 deforms one pair of sheath crimping members 47 to be bent inward (caulked), thereby crimping and fixing the sheath crimping member 45 to the insulation sheath 14 portion of the electric wire 11.

[0025] According to Fig. 4 and Fig. 5A and Fig. 5B, the terminal 31 is crimped to the electric cable 11 by a terminal crimping device 51. The terminal crimping device 51 has a counter bearing 52 and a crimping device 55. The counter bearing 52 is arranged in a lower part of the terminal 31 and the connected core wire 13A. The crimping device 55 is arranged in an upper part of the terminal 31 so that the connected core wire 13A is placed under the crimping device 55. The crimping device 55 is movable up and down relative to the counter bearing 52.

[0026] The counter bearing 52 has a bearing surface 53 at its upper part, which is curved so that it is recessed downward. When the terminal 31 is crimped onto the electrical cable, the bearing surface 53 supports the base part 46 of the terminal 31 thereon. Specifically, an outer surface of the base part 42 of the terminal 31 abuts against the bearing surface 53.

[0027] The squeezing device 55 is provided, in a central part of a width direction Dw, with a bulge groove 57 having a hill-shaped part 58 protruding toward the anvil support 52 side. The bulge groove 57 is formed with two round arc surfaces 57a provided in both sides of the hill-shaped part 58. Each of these round arc surfaces 57a is a round arc-shaped convex surface protruding in a direction separated from the support surface 53. The squeezing device 55 has two inclined guide surfaces 59. The inclined guide surfaces 59 are inclined so as to be gradually separated toward the anvil support 52 side. The inclined guide surfaces 59 are formed so as to be continuous to both ends of the bulge groove 57.

[0028] Next, the manufacturing method for the electric cable 1 with a terminal according to the present embodiment will be described in detail.

[0029] According to Fig. 1A, the insulation sheath 14 of one end portion of the electric wire 11 is stripped to a prescribed length to expose the core wire bundle 13 with the bundled conductor core wires 12. The prescribed length of the exposed core wire bundle 13 may be set to such a length that the terminal 31 is sufficiently pressure-fixed or welded to the electric wire.

[0030] According to Fig. 1B, the core wire bundle 13 exposed in the end portion of the electric cable 11 is bonded by the ultrasonic bonding process to form the bonded core wire 13A with the plurality of conductor core wires 12 connected to each other. Specifically, according to Fig. 3, the exposed core wire bundle 13 is placed in the forming space S of the ultrasonic bonding device 20, the sliding claw 23 is moved in the direction A, in which the sliding claw 23 comes close to the abutment plate 22, and the abutment 24 is moved in the direction B, in which the abutment 24 comes close to the grindstone 21, to press the core wire bundle 13 in the forming space S from both sides and upper and lower parts. Then, under this condition, an ultrasonic vibration is applied to the grindstone 21. This destroys the oxide layers that have formed on the surfaces of the conductor core wires 12 in the forming space S, thereby bonding the conductor core wires 12 together. Thus, according to Fig. 2C, the connected core wire 13A is formed, which is rectangular in sectional shape with a width X and a height Y. In the connected core wire 13A formed in this manner, the conductor core wires 12 are connected to each other in such a way as to be integrated to form the single wire. Thus, the conductor core wires 12 are arranged in a state where the conductor core wires 12 together exhibit satisfactory electrical conductivity.

[0031] According to Fig. 5A and Fig. 5B, in the ultrasonic bonding process, the bonded core wire 13A is formed in such a manner that a width X of a section orthogonal to an axis of the bonded core wire 13A is not more than a value obtained by subtracting twice a thickness T of the terminal 31 from a width W of the bulge groove 57 formed in the crimping device 55 of the terminal crimping device 51. That is, the value X is obtained by a formula “X ≤ W-2T”. Furthermore, according to Fig. 6, in the ultrasonic bonding process, the bonded core wire 13A is formed in such a manner that a height Y of the section orthogonal to the axis of the bonded core wire 13A is not less than a value obtained by subtracting twice the thickness T of the terminal 31 from a maximum distance H between the support surface 53 of the abutment 52 and the bulge groove 57 at the time of completion of press-fitting the terminal 31 by the terminal crimping device 51. That is, the value Y is obtained by a formula "Y ≥ H-2T." The thickness T of the terminal 31 is a thickness of a metal sheet constituting the terminal 31. Further, for convenience, the value (W-2T) that twice the thickness T of the terminal 31 is subtracted from the width W of the bulge groove 57 is also referred to as a "reference width."The value (H-2T) that twice the thickness T of the clamp 31 is subtracted from the maximum distance H between the bearing surface 53 of the counter bearing 52 and the bulge groove 57 of the crimping device 55 at the time of completion of the compression fastening of the clamp 31 by the clamp crimping device 51 is also referred to as a "reference height." In . Fig. 6 an altitude direction is shown as Dh.

[0032] According to Fig. 1D, the terminal 31 is crimped to the connected core wire 13A by means of the terminal crimping device 51. First, according to Fig. 5B, the terminal 31 is arranged and supported on the support surface 53 of the counter support 52. The end part of the electric wire 11 is arranged in the terminal 31. Here, in the terminal 31, before a crimping process is applied to the terminal 31, a space between the inner side walls of the conductor crimping parts 43 extending from the base bottom part 42 is sufficiently larger than the value (the reference width) that twice the thickness T of the terminal 31 is subtracted from the width W of the bulge groove 57 of the crimping device 55. Accordingly, when the connected core wire 13A of the electric wire 11 is arranged in the conductor crimping part 41 of the terminal 31, the connected core wire 13A whose width X is not more than the reference width (X ≤ W-2T) is not caught by the conductor crimping parts 43 of the terminal 31 and is arranged in the conductor crimping part 41.

[0033] After the end portion of the electric wire 11 is placed in the terminal 31, the crimping device 55 is lowered so that the crimping device 55 can come close to the abutment 52, thereby compressively crimping the terminal 31 to the electric wire 11. At this time, the end portions of the conductor crimping portions 43 of the terminal 31, which extend to both sides, come into contact with the inclined guide surfaces 59 of the crimping device 55. Thus, the conductor crimping portions 43 are deformed in directions in which the conductor crimping portions 43 come close to each other along the inclined guide surfaces 59 of the crimping device 55.At this time, since the width X of the cut orthogonal to the axis of the connected core wire 13A is not more than the reference width (X ≤ W-2T), the connected core wire 13A is not pressed by the terminal 31 until the conductor crimping parts 43 of the terminal 31 reach the bulge groove 57 and begin bending (until an actual caulking process starts). This prevents excessive external pressure from being exerted on the connected core wire 13A.

[0034] When the crimping device 55 is lowered further so that the crimping device 55 can come close to the counter bearing 52, the conductor crimping parts 43 for the terminal 31 reach the curvature groove 57 (see Fig. 5A). From this state, the conductor crimping portions 43 are pressed by the bulging groove 57 in directions in which the conductor crimping portions 43 come close to each other, and are deformed to be bent (rolled up) inward.

[0035] Thereafter, according to Fig. 6, the counter bearing 52 and the crimping device 55 come close to each other until the shape of a space between the support surface 53 and the round arc surfaces 57a forms a predetermined crimped shape. That is, at the time of completion of crimping of the terminal 31 by the terminal crimping device 51, the space between the support surface 53 and the round arc surfaces 57a defines the predetermined crimped shape. At this time, the conductor crimping part 41 of the terminal 31 is clamped between the counter bearing 52 and the crimping device 55 and pressed against the connected core wire 13A. Thus, according to Fig. 7, terminal 31 is tightly crimped to core wire bundle 13 (connected core wire 13A) without any gaps. Thus, terminal 31 is securely electrically conductive with core wire bundle 13 of electric cable 11.

[0036] Here, the height Y of the cut of the connected core wire 13A before the connected core wire 13A is crimped to the electric wire is set to the value (the reference height) that twice the thickness T of the terminal 31 is subtracted from the maximum distance H between the support surface 53 of the counter support 52 and the bulge groove 57 in a state where the space between the support surface 53 and the round arc surfaces 57a defines the predetermined crimped shape. Since the height Y is the reference height (Y = H - 2T), the occurrence of voids between the connected core wire 13A and the terminal 31 at the time of crimping completion is suppressed.

[0037] In the terminal crimping process, the sheath crimping portions 47 of the terminal 31 are crimped by a counter bearing and a crimping device (illustrations are omitted) for the sheath provided in the terminal crimping device 51. Thus, the sheath crimping portion 45 of the terminal 31 is crimped to the insulation sheath portion 14 of the electric cable 11.

[0038] As described above, in the manufacturing method for the electric wire 1 with the terminal according to the present embodiment, since the width X of the sectional shape orthogonal to the axis of the connected core wire 13A is not more than the reference width (X≤W-2T), when the terminal 31 is crimped to the connected core wire 13A, the connected core wire 13A is not crimped by the terminal 31 until the conductor crimping parts 43 of the terminal 31 reach the bulge groove 57 (until the actual caulking starts). This can prevent excessive external pressure from being applied to the connected core wire 13A. It can prevent the connection of the conductor core wires 12 in the connected core wire 13A from being canceled.Thus, even after the terminal 31 is crimped to the connected core wire 13A, resistance between the conductor core wires 12 connected to each other by the ultrasonic bonding process can be suppressed as much as possible, and satisfactory electrical conductivity of the core wire bundle 13 and the terminal 31 can be maintained.

[0039] Furthermore, since the height Y of the intersection of the connected core wire 13A is not less than the reference height (Y ≥ H-2T), hardly any voids or gaps are generated between the connected core wire 13A and the terminal 31 at the time of completion of the crimping of the terminal 31 to the connected core wire 13A. Thus, the electrical conductivity between the terminal 31 and the connected core wire 13A can be further improved.

[0040] The manufacturing method of the electric wire with the terminal according to the present embodiment is particularly effective when the terminal 31 is crimped to the electric wire 11 formed with the aluminum electric wire or the aluminum alloy electric wire, which is concerned about deterioration of the electric conductivity between the conductor core wires 12 in the central part of the core wire bundle 13.

[0041] The present invention is not limited to the above-described embodiment, and various modified examples can be adopted within the scope of the present invention. For example, the present invention is not limited to the above-described embodiment and can be appropriately modified and improved. In addition, the materials, shapes, dimensions, number, arranged positions, or the like of the components in the above-described exemplary embodiment can be arbitrarily selected as long as the present invention can be realized, and are not limited.

[0042] For example, as the electric wire 11, an electric wire (a copper electric wire) in which a conductor core wire 12 is formed with copper or a copper alloy may be used instead of the aluminum electric wire or the aluminum alloy electric wire. Furthermore, as the terminal 31, a terminal formed with aluminum or an aluminum alloy may be used instead of the terminal formed with copper or a copper alloy.

[0043] Here, the features of the above-described exemplary embodiment of the manufacturing method for an electric wire with a terminal according to the present invention are briefly summarized in (i) to (iii) described below, respectively. (i) A manufacturing method for an electric cable with a terminal, comprising: a step of connecting a plurality of core wires (12) by an ultrasonic bonding process to form a bonded core wire (13A); a step of arranging the connected core wire (13A) on a base bottom part (42) of a terminal (31) between a pair of crimping parts (43) extending from the base bottom part (42); a step of setting the clamp (31) on which the connected core wire (13A) is arranged onto a support (52) of a crimping device (51) so that the base bottom part (42) is supported on a support surface (53) of the support (52) under a crimping device (55) of the crimping device (51); and a step of crimping the terminal (31) to the connected core wire (13A) by causing the counter support (52) and the crimping device (55) to come close to each other, and deforming the crimping parts (43) by a bulging groove (57) of the crimping device (55) until a space between the support surface (53) and the bulging groove (57) defines a predetermined crimped shape, wherein in the step of connecting the plurality of core wires (12), the core wires (12) are formed into the connected core wire (13A) with a cross-sectional shape having a width (X) and a height (Y) in a plane orthogonal to an axis of the connected core wire (13A), the width (X) being not longer than the length obtained by subtracting twice a thickness (T) of the terminal (31) from a width (W) of the bulge groove (57) in a state where the space defines the predetermined crimped shape. (ii) A manufacturing process according to (i) above, wherein the height (Y) of the cross-sectional shape, which in the step of connecting the plurality of core wires (12) is orthogonal to the width (X) of the cross-sectional shape and not shorter than the length obtained by subtracting twice the thickness (T) of the clamp (31) from a maximum distance (H) between the bearing surface (53) and the round arc surfaces (57a) of the bulging groove (57) in the state in which the space defines the predetermined crimped shape. (iii) The manufacturing method according to the above (i) or (ii), wherein the plurality of conductor core wires (12) are made of at least aluminum or an aluminum alloy.

[0044] According to the manufacturing method for an electric cable with a terminal having the structure (i) described above, the width of the cut orthogonal to the axis of the connected core wire is not longer than the value (reference width) that is twice the thickness of the terminal subtracted from the width of the bulging groove. Therefore, when the terminal is crimped to the connected core wire, the connected core wire is not pressed by the terminal (the crimping parts) until the crimping parts of the terminal begin to be bent by the bulging groove (until the actual crimping process starts) (see Fig. 5A and Fig. 5B). When the terminal is crimped to the connected core wire, it can better prevent excessive external force from being applied to the connected core wire, and the shape cancellation of a single wire of the connected core wire can be avoided more effectively than in a case where the width of the cut of the connected core wire is larger than the reference width. As a result, during a process in which the terminal is caulked, the shape cancellation of the single wire of the core wire bundle (the connected core wire) can be prevented as much as possible.

[0045] Accordingly, in the manufacturing method having the above-described structure, the terminal can be crimped to the connected core wire while maintaining a connected state of the connected core wire with the plurality of interconnected conductor core wires as much as possible.

[0046] According to the manufacturing method for an electric cable with a terminal having the structure (ii) described above, the height of the cut is not shorter than the value (the reference height) that is twice the thickness of the terminal is subtracted from the maximum distance between the counter support (the bearing surface) and the crimping device (the round arc surfaces) at the time of completion of the compression fitting (in the state where the space between the bearing surface and the bulge groove defines the predetermined crimped shape). Accordingly, under a state that the crimping operation is completed, the connected core wire comes into close contact with the terminal, so that hardly any voids or cavities are generated between the connected core wire and the terminal (see Fig.6). Thus, according to the manufacturing process with the structure described above, complete electrical conductivity between the terminal and the connected core wire can be further improved.

[0047] In the manufacturing method of an electric cable with a terminal having the structure (iii) described above, when the terminal is crimped to the conductor core wire (an aluminum wire) made of aluminum or an aluminum alloy in which the insulating property of an oxide film formed on the surface is higher than a conductor core wire (a copper wire) made of copper which is usually used, the various kinds of effects described above can be obtained.

[0048] According to the present invention, there can be provided the manufacturing method of an electric wire having a terminal in which the terminal can be crimped to a connected core wire while maintaining a connected state of the connected core wire with the plurality of conductor core wires connected together as much as possible. List of reference symbols: 1 electrical cable with a terminal 31 11 electrical cables 12 conductor core wires 13 core wire bundles 13A connected core wire 14 Insulation jacket 20 Ultrasonic connecting device 21 Whetstone 22 Counter bearing plate 23 Sliding claw 24 counter bearings 31 terminal 32 electrical connector 33 Squeeze part 34 Connecting plate part 34a connecting hole 41 Conductor crimping part 42 Base part of the conductor crimping part 41 43 conductor crimps 45 cover crimp 46 Base bottom part of the casing crimp part 45 51 Terminal crimping device 52 counter bearings 53 storage space 55 squeezing device 57 Curvature groove 57a round arched surfaces 58 hill-shaped part 59 inclined guide surfaces A Direction of movement of the sliding claw 23 B Direction of movement of the counter bearing 24 D w Width direction of the terminal crimping device 51 D h Height direction of the terminal crimping device 51 H maximum distance between the bearing surface 53 of the counter bearing 52 and the camber groove 57 of the squeezing device 55 S forming room T Thickness of the clamp 31 W Width of the convex groove 57 of the squeezing device 55 X Width of the cut shape of the connected core wire 13A Y Height of the cut shape of the connected core wire 13A

Claims

[1] Manufacturing method for an electric cable with a terminal, comprising: a step of connecting a plurality of core wires (12) by an ultrasonic bonding process to form a bonded core wire (13A); a step of arranging the connected core wire (13A) on a base bottom part (42) of a terminal (31) between a pair of crimping parts (43) extending from the bottom base part (42); a step of adjusting the clamp (31) on which the connected core wire (13A) is arranged on a support (52) of a crimping device (51) so that the base bottom part (42) is supported on a support surface (53) of the support (52) under the crimping device (55) of the crimping device (51); and a step of crimping the terminal (31) to the connected core wire (13A) by causing the counter support (52) and the crimping device (55) to come close to each other, and deforming the crimping parts (43) by a bulging groove (57) of the crimping device (55) until a space between the support surface (53) and the bulging groove (57) defines a predetermined crimped shape, wherein in the step of connecting the plurality of core wires (12), the core wires (12) are formed into the connected core wire (13A) having a rectangular cross-sectional shape with a width (X) and a height (Y) in a plane orthogonal to an axis of the connected core wire (13A), characterized by , that the width (X) is not longer than a length obtained by subtracting twice a thickness (T) of the clamp (31) from a width (W) of the bulge groove (57) in a state in which the space defines the predetermined squeezed shape, wherein the height (Y) of the rectangular cross-sectional shape formed in the step of connecting the plurality of core wires (12) is orthogonal to the width (X) of the cross-sectional shape and not shorter than a length obtained by subtracting twice the thickness (T) of the clamp (31) from a maximum distance (H) between the bearing surface (53) and round arc surfaces (57a) of the bulging groove (57) in a state in which the space defines a predetermined crimped shape, wherein the bulging groove (57) has two round arc surfaces (57a) projecting in a direction separated from the support surface (53), extending in a longitudinal direction of the connected core wire (13A), and lined up in a width direction (Dw), and wherein, when a distance from an outer end of one of the two round arc surfaces (57a) to an outer end of the other of the two round arc surfaces (57a) in the width direction is a width (W) of the bulge groove (57), an inner distance between the pair of crimping pieces (43) extending in a vertical direction before the crimping step is larger than a value obtained by subtracting twice the thickness (T) of the clamp (31) from the width (W) of the bulge groove (57). [2] A manufacturing method according to claim 1, wherein the plurality of core wires (12) are made of at least aluminum or an aluminum alloy.

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