Conductor crimping structure using connection terminal

Abstract

To more firmly crimp and fix an electric wire conductor by a conductor crimping unit to ensure reliability of electrical connection.SOLUTION: In a conductor crimping unit 3, first and second crimping pieces 3e, 3f each having a two-layer structure of an inner layer plate 3b and an outer layer plate 3a, are raised in a U-shape in advance. Further, void portions 3c, 3d are formed between the outer layer plate 3a and the inner layer plate 3b at folded portions of the crimping pieces 3e, 3f. A conductor 6 made of a single body is disposed between the crimping pieces 3e, 3f. The outer layer plate 3a and the inner layer plate 3b, particularly, the first and second crimping pieces 3e, 3f are crushed by an upper press mold Pu and a lower press mold Pd of a conductor crimping apparatus to caulk and fix the conductor 6 from all sides. In the caulking, pressing forces in two directions, which are a pressing force from below toward the center of the conductor 6 and a pressing force from obliquely upward toward the center of the conductor 6, are applied to form non-pressing portions 3n, 3o, 3p between the inner layer plate 3b and the conductor 6 between pressing portions 3k, 3l, 3m in contact with the conductor 6.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a conductor crimping structure using small connection terminals that are fitted inside a connector housing, for example, and that mate with connection terminals of a mating connector. [Background technology]

[0002] As electrical components become smaller, lighter, and more integrated, there is a constant demand for smaller connection terminals used to connect circuits. For this reason, a crimp connection terminal according to Patent Document 1 is disclosed that is compatible with thinner electric wire conductors.

[0003] The crimp connection terminal of Patent Document 1 has crimp pieces with a two-layer structure, with a gap formed between the crimp pieces of this two-layer structure, and by crimping and fixing with a crimping force that has moderate elasticity to maintain this gap without applying an excessive crimping force to the thin conductor, causing excessive deformation, etc., it is possible to reliably crimp and connect a thin conductor made of twisted wire.

[0004] Conventionally, most conductors used are made of multiple twisted core wires, and the conductor itself has a certain degree of flexibility and plasticity. Therefore, if the conductor is crimped with a crimping force having an appropriate elasticity using the crimping connection terminal with a gap as described in Patent Document 1, the conductor will not be unnaturally deformed even if it is a thin wire, and electrical properties such as conductivity and mechanical properties such as pull-out will not be deteriorated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-71920 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in recent years, mainly from the viewpoint of economy, attempts have been made to use metal wires such as simple copper alloys as conductors for signal wires connected to connection terminals, and the diameter of these wires is made to be ultra-fine wires of about 0.25 to 0.6 mm.

[0007] When connecting such a thin conductor made of a single piece with a conventional terminal crimping piece, the cross section generally has a crimp structure as shown in Fig. 12. However, unlike a conductor with twisted core wires, a single piece of conductor a has little flexibility or plasticity and is close to a rigid body, and particularly in the case of a thin conductor a, even if it is fixed with crimping piece b, crimping piece b does not necessarily crimp the circumference of conductor a with an even crimping force, and sufficient mechanical fixing force and electrical conductivity are not necessarily obtained.

[0008] Moreover, when a thin conductor made of a single unit is used, the conductor often cannot be crimped well, and mechanical and electrical problems are likely to occur, even when a crimp connection terminal having a gap as in Patent Document 1 is used. On the other hand, for normal conductors, oxides and sulfides that occur on the surface of the conductor and cause electrical hindrance are easily destroyed and removed during crimping, but there is a problem that it is extremely difficult to remove these oxides and sulfides from a thin conductor made of a single unit.

[0009] An object of the present invention is to solve the above-mentioned problems and provide a conductor crimping structure using a connection terminal that can reliably crimp a conductor to achieve good fixing force and conductivity, even if the conductor is made of a single wire. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the conductor crimping structure using a connection terminal of the present invention is a conductor crimping structure using a connection terminal in which a conductor crimping portion is formed by punching and bending a conductive metal plate, and a crimp connection terminal having a pair of crimping pieces raised in a U-shape from the bottom of the conductor crimping portion is used, and the conductor is crimped and fixed by the crimping pieces, wherein each of the crimping pieces has a two-layer structure consisting of an outer layer plate and an inner layer plate which is folded inward from a folded-over portion at the upper end of the outer layer plate and laminated on the outer layer plate, and a gap is provided on the inside of the folded-over portion between the outer layer plate and the inner layer plate, and between the inner layer plate and the conductor, there are three pressing portions which are fixed in a contact state by pressing forces in three directions from the directions of the bottom and the pair of gaps toward the center of the conductor when the conductor is crimped by the crimping pieces, and three non-pressing portions which are provided between these pressing portions and serve as gaps. Effect of the Invention

[0011] According to the conductor crimping structure using the connection terminal of the present invention, the conductor is crimped using a gap provided in the two-layer crimping piece, and pressing parts that concentrate a strong pressing force locally on the conductor are provided in three locations. In addition, non-pressing parts that are gaps are provided between the conductor and the crimping pieces at three locations adjacent to these pressing parts, thereby enabling the conductor to be securely fixed by crimping, and mechanical and electrical reliability can be ensured. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view of a crimp connection terminal to be used. [Diagram 2] FIG. 2 is a plan view of a stamped conductive metal plate. [Diagram 3] FIG. 11 is a perspective view of the conductor crimping portion in one step of a bending process. [Figure 4] FIG. 11 is a cross-sectional view of the crimping piece at the front of the crimping portion raised into a U-shape. [Diagram 5] FIG. 13 is a cross-sectional view of the crimping piece at the rear of the crimping portion raised into a U-shape. [Figure 6] 13 is an explanatory diagram of a state in which a conductor is disposed within the first and second crimping pieces of the front crimping portion. FIG. [Figure 7] FIG. 2 is a cross-sectional structural view of the front crimping portion in crimping step 1. [Figure 8] FIG. 13 is a cross-sectional structural view of the front crimping portion in crimping step 2. [Figure 9] FIG. 13 is a cross-sectional structural view of the front crimping portion in crimping step 3. [Figure 10] FIG. 13 is a cross-sectional structural view of the front crimping portion in crimping step 4. [Figure 11] 3 is a perspective view of the crimp connection terminal with the conductor crimped and fixed thereto; FIG. [Figure 12] FIG. 1 is a cross-sectional view of a conventional crimping and fixing structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention will be described in detail based on the embodiments shown in FIGS. 1 is a perspective view of a crimp connection terminal 1 according to an embodiment of the present invention, which is used in a conductor crimping structure using a connection terminal according to the present invention. This crimp connection terminal 1 is made of thin brass, for example 0.1 mm thick, and is punched out from a single conductive metal plate with both surfaces previously plated with copper or tin, and the connection section, crimping section, etc. are formed by bending.

[0014] A connection portion 2, e.g. a male insertion portion, for connecting with a connection terminal of a mating connector is formed on the front side of the crimp connection terminal 1, and a conductor crimping portion 3 and an insulation crimping portion 4 are arranged in sequence on the rear side. The conductor crimping portion 3 is divided into a front crimping portion 3X and a rear crimping portion 3Y from the front along the longitudinal direction. An actual crimp connection terminal 1 may be provided with a stabilizer for stabilizing its position within the connector housing, a locking portion for preventing it from slipping out of the connector housing in the front-rear direction, etc., but these well-known mechanisms are not shown in the drawings.

[0015] 2 is a plan view of the conductive metal plate 5 in a punched state before being formed into the crimp connection terminal 1, with the connection portion 2, conductor crimping portion 3, and coating crimping portion 4 being compartmentalized in a planar shape as a material. Behind the coating crimping portion 4 is provided a feed piece 5a for connecting the crimp connection terminals 1 in the punched state, and the coating crimping portion 4 at the rear end of each crimp connection terminal 1 is connected to the feed piece 5a via a connecting piece 5b. The feed piece 5a is provided with a pilot hole 5c, which is used to intermittently transport the conductive metal plate 5 in the subsequent forming process of the crimp connection terminal 1.

[0016] The conductive metal plate 5 punched out in this manner is subjected to, for example, chamfering or surface treatment as necessary, and then conveyed by the feed piece 5a, in each forming process by a forming press, the connection portion 2, the conductor crimping portion 3, and the coating crimping portion 4 are successively bent to form the crimp connection terminal 1 shown in Fig. 1. After forming, the linking piece 5b is cut, and each crimp connection terminal 1 is separated into individual pieces.

[0017] 1 and 2, in the connection part 2, folded pieces 2b and 2c which form the upper plate are folded upward along the dotted lines from both sides of the bottom plate 2a which forms the lower plate of the conductive metal plate 5, and furthermore, the edges of the folded pieces 2b and 2c are butted together to form a male insertion end with a two-layer structure. Note that the connection part 2 may have another male shape or may be a female receptacle connection part.

[0018] In the conductive metal plate 5 shown in Fig. 2, the crimping front portion 3X and the crimping front portion 3X are each composed of an outer layer plate 3a arranged in the center and two inner layer plates 3b extending in the width direction from both sides of the outer layer plate 3a and having different width lengths. The two dotted lines in the longitudinal direction of the conductor crimping portion 3 indicate the positions where the inner layer plate 3b is folded back inward from the outer layer plate 3a in the folding process described later.

[0019] 3 is a perspective view of the conductor crimping portion 3 in one step of the bending process. In the front crimping portion 3X and the rear crimping portion 3Y, the inner layer plate 3b is folded inward from the upper end of the outer layer plate 3a at the folded portion to form a two-layer structure. The width of the inner layer plate 3b on one side of the front crimping portion 3X is elongated, and the width of the inner layer plate 3b on the other side of the rear crimping portion 3Y is elongated. Furthermore, between the inner layer plate 3b and the outer layer plate 3a at the folded portion of the front crimping portion 3X and the rear crimping portion 3Y, gaps 3c and 3d having cross sections, for example, a water drop shape, a balloon shape, a circle shape, an ellipse shape, etc. are formed. The gap 3c of the front crimping portion 3X communicates with the gap 3d of the rear crimping portion 3Y, and the gap 3d of the front crimping portion 3X communicates with the gap 3c of the rear crimping portion 3Y.

[0020] In the next folding process, in the crimped front part 3X and the crimped rear part 3Y, the outer layer plate 3a and the inner layer plate 3b on both sides are raised in a U-shape diagonally upward as the first and second crimped pieces 3e and 3f, as shown in Figs. 4 and 5, respectively. In this state, the crimped front part 3X and the crimped rear part 3Y are bilaterally symmetrical. The inner layer plate 3b on the first crimped piece 3e side of the crimped front part 3X is directed downward from the folded part of the upper end of the outer layer plate 3a, and the edge part 3g covers the bottom part of the outer layer plate 3a and further extends long along the outer layer plate 3a to approximately the middle position of the rising part of the second crimped piece 3f. On the other hand, the inner layer plate 3b on the second crimped piece 3f side is directed downward from the folded part of the upper end of the outer layer plate 3a, and the edge part 3h is extended short to approximately the middle position of the rising part of the second crimped piece 3f. A gap 3i is formed between the edge portions 3g and 3h of the inner layer plate 3b along the outer layer plate 3a.

[0021] The reason why the front crimping portion 3X and the rear crimping portion 3Y are symmetrical in this manner is that if the length of the conductor crimping portion 3 is increased, the crimping force on the conductor is likely to become unbalanced on the left and right in the crimping process described below, and this prevents the crimp connection terminal 1 from twisting and applies the crimping force evenly on the left and right.

[0022] When crimping a single conductor 6 with the crimp connection terminal 1, first, as shown in Fig. 6, the conductor 6 made of a metal wire, for example, a copper alloy, with its insulating coating stripped off and having a diameter of, for example, 0.32 mm, is inserted between the first and second crimping pieces 3e, 3f of the crimping front part 3X along the longitudinal direction of the crimp connection terminal 1, and placed on the bottom part 3j of the inner layer plate 3b. Note that crimping of the conductor 6 is performed simultaneously and in the same manner in the crimping rear part 3Y as well, so the subsequent crimping steps will be described only for the crimping front part 3X.

[0023] In the process of crimping the conductor 6 by the conductor crimping device, the upper press die Pu is lowered and the lower press die Pd is raised relatively with the first and second crimping pieces 3e, 3f disposed between the upper press die Pu and the lower press die Pd. The upper press die Pu and the lower press die Pd are adapted to operate together without distinguishing between the front crimping portion 3X and the rear crimping portion 3Y.

[0024] By the operation of the upper press die Pu and the lower press die Pd, the first and second crimping pieces 3e, 3f are deformed to encase the conductor 6 according to the shapes of the upper press die Pu and the lower press die Pd, as shown in Fig. 7. During this process, the gap 3i between the edge portions 3g, 3h of the inner layer plate 3b is reduced by the crimping of the first and second crimping pieces 3e, 3f, and the voids 3c, 3d are also reduced, the side of the outer layer plate 3a is raised by the upper press die Pu, and the bottom portion formed by the outer layer plate 3a and the inner layer plate 3b is deformed from a U-shape to a flattened shape along the lower press die Pd.

[0025] Furthermore, as shown in Fig. 8, by operating the press upper die Pu and the press lower die Pd, a strong crimping force is applied to the first and second crimping pieces 3e, 3f, which deforms the first and second crimping pieces 3e, 3f to further envelop the conductor 6. At this time, pressing forces are applied to the conductor 6 mainly from three directions indicated by arrows, that is, pressing forces toward the center of the conductor 6 from the direction of the bottom 3j, and pressing forces toward the center of the conductor 6 from both the left and right diagonal directions. The angles of these pressing forces in the three directions are spaced apart by approximately 120 degrees.

[0026] As a result of further crimping, the thicknesses of the outer layer plate 3a and the inner layer plate 3b increase during the crimping process in the first and second crimping pieces 3e and 3f, and the size of the gaps 3c and 3d is further reduced, as shown in Fig. 9. During this crimping process, the pressing force from the press upper die Pu and the press lower die Pd is locally concentrated particularly from the three directions mentioned above, and at the three locations where this pressing force is concentrated, pressing portions 3k, 3l, and 3m are provided where the inner layer plate 3d contacts the conductor 6, and at three locations along the conductor 6 between these pressing portions 3k, 3l, and 3m, no pressing force is applied from the inner layer plate 3d to the conductor 6, and three non-pressing portions 3n, 3o, and 3p are provided as gaps between the inner layer plate 3d and the conductor 6 in these locations.

[0027] In other words, by concentrating the pressing force that fixes the conductor 6 against its outer peripheral surface at three points, the coating made of oxides and sulfides in this portion of the conductor 6 at pressing portions 3k, 3l, and 3m can be destroyed and removed, thereby improving the reliability of the electrical connection between the inner layer plate 3d.

[0028] When the pressing by the upper press die Pu and the lower press die Pd occurs, the following phenomena generally occur until pressed portions 3k, 3l, 3m and non-pressed portions 3n, 3o, 3p are formed between the inner layer board 3b and the conductor 6.

[0029] The outer layer plate 3a is deformed by the pressing force of the upper press die Pu and the lower press die Pd, and is plastically deformed when the pressure exceeds the yield point. Therefore, even if the pressure of the upper press die Pu and the lower press die Pd is released, the outer layer plate 3a does not return to its original shape. In contrast, the inner layer plate 3b is subjected to the pressing force of the upper press die Pu and the lower press die Pd through the outer layer plate 3a. The portion of the inner layer plate 3b that extends along the outer layer plate 3a is plastically deformed into a shape along the outer layer plate 3a.

[0030] In addition, in the part of the inner layer board 3b extending along the gaps 3c and 3d, the pressing force applied to the inner layer board 3b through the outer layer board 3a is used to reduce the gap 3i between the edge parts 3g and 3h of the inner layer board 3b, and then to reduce the gaps 3c and 3d. Therefore, even if the pressing force applied to the outer layer board 3a exceeds the yield point of the outer layer board 3a, the pressing force applied to the inner layer board 3b does not immediately exceed the yield point of the inner layer board 3b. Therefore, by utilizing the difference in the way the pressing force is applied between the outer layer board 3a and the inner layer board 3b, it is possible to prevent the entire deformation of the inner layer board 3b from becoming plastically deformed, and to leave a part that remains elastically deformed.

[0031] Therefore, when the pressure from the press upper die Pu and press lower die Pd is released, an elastic restoring force is generated in the inner layer plate 3b, which causes the gaps 3c and 3d, which have been reduced by elastic deformation, to expand to their original size. This elastic restoring force tries to push the parts of the inner layer plate 3b that extend along the gaps 3c and 3d in a direction away from the outer layer plate 3a, that is, inward. At this time, the inner layer plate 3b, which is being pushed back inward, comes into contact with the conductor 6 and presses it, and the inner layer plate 3b comes into contact with the conductor 6 with a biasing force, so that the conductor 6 is crimped between the inner layer plates 3b.

[0032] In this embodiment, the following effects can be obtained by combining the first and second crimping pieces 3e, 3f that enable such crimping with the conductor 6 made of a single body.

[0033] When a conductor is made of multiple twisted core wires, there are gaps between each core wire, so when the conductor is pressed by the inner layer plate 3b, each core wire moves to fill the gaps between them. As a result, the overall shape of the conductor changes to a shape that conforms to the shape of the space surrounded by the inner layer plate 3b. Because the pressing force from the inner layer plate 3b is used to move each core wire, the pressing force that each core wire receives from the inner layer plate 3b is smaller than when the conductor is made of a single wire. Accordingly, the degree to which the coating such as oxide that covers the surface of each core wire is destroyed is also smaller.

[0034] In contrast, when the conductor 6 is a single piece, the core wires do not move as they do when the conductor is made of multiple twisted core wires, and so the pressing force from the inner layer plate 3b continues to be concentrated at three points on the conductor 6. As a result, although the contact area between the conductor 6 and the inner layer plate 3b is small, contact with a large biasing force is possible at the three pressing parts 3k, 3l, and 3m where the conductor 6 and the inner layer plate 3b come into contact, so that sufficient mechanical and electrical performance can be obtained, and furthermore, it is possible to destroy and remove the coating made of oxides, etc.

[0035] The above-mentioned effects could not be predicted when a conductor made of multiple twisted core wires is used, but were newly discovered in the present invention using a single conductor 6. That is, when a conductor made of multiple twisted core wires is used, the conductor makes contact on the circumferential surface in cross section, whereas when a solid wire is used as the conductor, the conductor makes contact at multiple points, and the two concepts are different from each other.

[0036] In this way, in addition to the gaps 3c and 3d, three non-pressed portions 3n, 3o, and 3p are provided between the upper and lower sides of the conductor 6 and the inner layer plate 3b, and the conductor 6 is crimped by the outer layer plate 3a and the inner layer plate 3b, thereby obtaining a conductor crimping structure using a connection terminal in which the gaps 3c, 3d and the non-pressed portions 3n, 3o, and 3p are further reduced, as shown in Figure 10. With this structure, the conductor 6 is crimped reliably while maintaining its elasticity, ensuring electrical and mechanical reliability.

[0037] Furthermore, in the coating crimping portion 4, the outer side of the insulating coating portion 7 is crimped by the pair of coating crimping pieces 4a, 4b of the coating crimping portion 4 using a coating crimping device that works in conjunction with the conductor crimping device, thereby crimping the sides 4c, 4d so as to bite into the insulating coating portion 7. This allows the coating crimping portion 4 to fix the insulating coating portion 7 and resist the pull-out force acting on the electric wire.

[0038] FIG. 11 shows a state in which the conductor 6 is crimped and connected by the front crimping portion 3X and rear crimping portion 3Y of the conductor crimping portion 3, and the insulating coating portion 7 is crimped and fixed by the coating crimping pieces 4a and 4b of the coating crimping portion 4.

[0039] In the embodiment, the conductor crimping portion 3 is divided into the front crimping portion 3X and the rear crimping portion 3Y, but the conductor crimping portion 3 may have only one of these shapes as a whole without being divided in this way. Also, the length of the inner layer plate 3b may be equal on the left and right, and may be symmetrical on the left and right.

[0040] Furthermore, in the embodiment, the gaps 3c, 3d are formed in advance in the crimp connection terminal 1, but during the conductor crimping process, the gaps 3c, 3d can also be formed between the outer layer board 3a and the inner layer board 3b depending on the shape of the press upper die Pu.

[0041] The terms up and down, left and right, front and rear used in this specification are used for explaining the drawings and do not limit the present invention. [Explanation of symbols]

[0042] 1 Crimp connection terminal 2 Connection 3 Conductor crimping section 3X Crimp Front 3Y Crimp Rear 3a Outer plate 3b Inner layer 3c, 3d void area 3e, 3f Crimping piece 3k, 3l, 3m pressing part 3n, 3o, 3p non-pressing part 4 Covering crimp part 5 Conductive metal plate 6 Conductors 7 Insulating coating

Claims

1. A conductor crimping structure using a connection terminal, comprising: a conductive metal plate is punched and bent to form a conductor crimping portion; and a crimp connection terminal having a pair of crimping pieces standing up in a U-shape from a bottom of the conductor crimping portion, the crimping pieces being used to crimp and fix the conductor, Each of the pressure-bonding pieces has a two-layer structure including an outer layer plate and an inner layer plate folded inward from a folded-back portion at an upper end of the outer layer plate and laminated on the outer layer plate, A gap is provided on the inside of the folded portion between the outer layer board and the inner layer board, A conductor crimping structure using a connection terminal, characterized in that between the inner layer plate and the conductor, there are three pressing portions which are fixed in a contact state by pressing forces in three directions from the directions of the bottom and the pair of gap portions toward the center of the conductor when the conductor is crimped by the crimping piece, and three non-pressing portions which are provided between these pressing portions and serve as gaps.

2. 2. The conductor crimping structure using a connection terminal according to claim 1, wherein the conductor is made of a single metal wire.

3. 3. The conductor crimping structure using a connection terminal according to claim 1, wherein the pressure forces in the three directions are applied to the conductor from directions spaced apart by approximately 120 degrees.

4. 4. A conductor crimping structure using a connection terminal as described in any one of claims 1 to 3, characterized in that the gap provided between the outer layer plate and the inner layer plate is formed in advance in the crimp connection terminal.

Images