JP2020004673A - Terminal - Google Patents

Abstract

To provide a terminal excellent in mechanical strength, durability and water cut-off performance of a neck part by preventing occurrence of surface defects and internal defects during welding and occurrence of cracks due to non-uniformity of internal stress and bending at the neck part.SOLUTION: A terminal 1 includes a cylindrical crimping part 30 where a wire is connected by crimping, a connector part 20 connected to a connection destination, and a neck part 40, the neck part 40 having a heat affected zone 70 formed by welding. The terminal is formed of a metal member which contains Cr: 0.00 mass% or more and 0.35 mass% or less, P: 0.00 mass% or more and 0.15 mass% or less, and Mg: 0.05 mass% or more and 0.8 mass% or less, with the balance consisting of Cu and unavoidable impurities, the metal member having an average thickness of 0.38 mm or more and 0.80 mm or less and a conductivity of 60%IACS or more and 85%IACS or less. The ratio of the average hardness of a non-heat affected zone 71 to the average hardness of the heat affected zone 70 at the neck part 40 is 1.1 or more and 1.8 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a terminal capable of preventing the occurrence of surface defects and internal defects at the time of welding and the occurrence of cracks at the time of bending, and having excellent mechanical strength and waterproofness, and capable of crimping and connecting a large-diameter electric wire. .

  2. Description of the Related Art Conventionally, connection between an electric wire and a terminal in an automobile wire harness or the like is generally performed by crimping by crimping an electric wire with a terminal called an open barrel type. However, in the case of an open barrel type terminal, if moisture or the like adheres to the connection portion (contact point) between the electric wire and the terminal, oxidation or corrosion of the metal surface used for the electric wire or the terminal proceeds, and the electric resistance at the connection portion increases. Would. The progress of oxidation and corrosion of the metal at the connection portion between the electric wire and the terminal causes cracks and poor contact at the connection portion, which affects the product life and connection reliability.

  In addition, when processing cracks occur during crimping connection between the electric wire and the terminal, and if moisture or the like adheres to the portion of the processing crack, oxidation or corrosion of the metal surface used for the electric wire or the terminal also proceeds. Therefore, there is a demand for a terminal that is excellent in processing cracks at the time of crimping connection between an electric wire and a terminal and that has excellent waterproofness after crimping connection.

  It has been proposed to form a normal portion and an annealed portion on a metal member in a non-welded portion of a cylindrical crimping portion as a terminal having processing cracks at the time of crimping connection and waterproofness after the crimping connection (Patent Document 1). ). In Patent Literature 1, since the attachment of moisture from the outside to the contact between the electric wire and the terminal base material can be prevented, it is possible to reduce the oxidation and corrosion of the metal constituting the electric wire and the terminal, and the terminal has an annealed portion. By having this, it is possible to prevent processing cracks during crimping of the cylindrical crimping portion.

  On the other hand, an aluminum wire having a large diameter may be used for a wire harness for an automobile or the like in order to supply a large current. In a large-diameter aluminum electric wire through which a large current flows, it is necessary to reduce the electric resistance of the terminal, so that it is necessary to use a metal member having a small volume resistivity. Since a metal member having a small volume resistivity has a high thermal conductivity, the thermal energy introduced at the time of laser welding is easily released, so that a high output of the laser is required. When the output of the laser is increased, the additional element and the plating material of the metal member are liable to evaporate, so that surface defects such as spatter, voids and cracks and internal defects are easily generated in the laser welded portion. In addition, a metal member having a high thermal conductivity has a high cooling rate, so that surface defects such as voids and cracks and internal defects are easily generated.

  In addition, non-uniformity of internal stress occurs due to thermal expansion and contraction during laser welding and residual processing stress when bending a plate-shaped metal member to a terminal, and cracks are particularly likely to occur at the neck of the terminal. . Also, in order to crimp and connect a large diameter aluminum electric wire, it is necessary to use a thick terminal. When the thickness of the metal member is increased, there is also a problem that cracks tend to occur particularly in the bent portion forming the neck.

  Therefore, even when a large-diameter electric wire is crimp-connected to a terminal, it is required to prevent the occurrence of surface defects and internal defects of the welded portion and the occurrence of cracks in the neck portion, and to provide mechanical strength and waterproofness. ing. However, in Patent Literature 1, there is room for improvement in preventing the occurrence of cracks in the neck and improving mechanical strength, durability, and waterproofness when a large-diameter electric wire is crimped and connected.

International Publication No. WO 2014/017660

  In view of the above-described circumstances, the present invention provides a method for crimping a wire having a large diameter, even if a metal member having a small volume resistivity and a large thickness is used, the occurrence of surface defects and internal defects at the time of welding, and a problem in a neck portion. Another object of the present invention is to provide a terminal having excellent mechanical strength, durability and waterproofness of a neck portion by preventing unevenness of internal stress and generation of cracks due to bending.

The gist of the configuration of the present invention is as follows.
[1] The tube includes a tubular crimping portion to which an electric wire is crimped and connected, a connector portion connected to a mating connection destination, and a neck portion provided between the tubular crimping portion and the connector portion. A crimped portion having a heat-affected portion formed by welding and a non-heat-affected portion that is a different region from the heat-affected portion, and the neck portion being a terminal having the heat-affected portion formed by welding. hand,
The terminal has a Cr content of 0.00 mass% or more and 0.35 mass% or less, a P content of 0.00 mass% or more and 0.15 mass% or less, a Mg content of 0.05 mass% or more and 0.8 mass% or less, and a balance of Cu and inevitable impurities. It is made of a metal member having an average thickness of 0.38 mm or more and 0.80 mm or less, and a conductivity of 60% IACS or more and 85% IACS or less,
A terminal in which a ratio of an average hardness of the non-heat-affected zone to an average hardness of the heat-affected zone in the neck is 1.1 or more and 1.8 or less.
[2] The terminal according to [1], wherein Cr is 0.15% by mass or more and 0.35% by mass or less.
[3] The terminal according to [1] or [2], wherein P is 0.005% by mass or more and 0.15% by mass or less.
[4] The ratio of the average hardness of the non-heat-affected zone to the average hardness of the heat-affected zone in the cylindrical pressure-bonded portion, wherein the ratio of the average hardness is 1.1 or more and 1.7 or less. The terminal according to any one of the above.
[5] Any one of [1] to [4], wherein a width of the heat-affected zone in the wire insertion direction of the neck is 1.0 to 4.0 times a thickness of the heat-affected zone of the neck. Terminal described in one.
[6] The terminal according to any one of [1] to [5], wherein the average crystal grain size in the heat-affected zone of the neck is 5 μm or more and 30 μm or less.
[7] The terminal according to any one of [1] to [6], which is formed from the metal member plated with Ni and / or Sn.
[8] When one end of the terminal is reciprocally oscillated in a direction perpendicular to the wire insertion direction such that the heat-affected zone of the neck has an elongation rate of 0.05% in the wire insertion direction, 10 million times The terminal according to any one of [1] to [7], wherein the neck portion is not destroyed even when reciprocating.

  In the present specification, the “heat-affected zone” is a region including a welded portion formed by welding, and means a portion softened by welding and reduced to 90% or less of the hardness of the metal member before welding. The “non-heat-affected zone” is a portion that is not affected by heat due to welding, and is a portion of the hardness of the metal member before welding. In the present specification, “hardness” means Vickers hardness. Vickers hardness can be measured by a method according to JIS Z 2244.

  In the terminal [1], 0.00 mass% of Cr means that Cr is not contained, and 0.00 mass% of P means that P is not contained. P is an optional component.

  According to the aspect of the terminal of the present invention, Cr is 0.00 mass% or more and 0.35 mass% or less, P is 0.00 mass% or more and 0.15 mass% or less, Mg is 0.05 mass% or more and 0.8 mass% or less, and the balance is Is a metal member composed of Cu and unavoidable impurities, whereby an excellent electrical conductivity of 60% IACS or more and 85% IACS or less can be obtained. Further, the use of the metal member having the above components can prevent surface defects and internal defects at the time of welding, so that cracks can be formed even when a plate material having an average thickness of 0.38 mm or more and 0.80 mm or less is bent and bent. Occurrence can be prevented. Furthermore, since the ratio of the average hardness of the non-heat-affected zone to the average hardness of the heat-affected zone at the neck is 1.1 or more and 1.8 or less, the occurrence of cracks due to the non-uniformity of internal stress at the neck is reduced. Can be prevented, and the durability can be improved.

  Therefore, even if a thick metal member having a small volume resistivity and a large thickness is used for crimping a wire having a large diameter, the occurrence of surface defects and internal defects at the time of welding and the occurrence of internal stress at the neck of the terminal are not affected. Generation of cracks due to uniformity and generation of cracks due to bending can be prevented. As a result, it is possible to obtain a terminal having excellent mechanical strength, durability and waterproofness at the neck.

  According to the aspect of the terminal of the present invention, the ratio of the average hardness of the non-heat-affected zone to the average hardness of the heat-affected zone in the cylindrical crimped portion is 1.1 or more and 1.7 or less, so that only the neck portion is formed. Instead, the occurrence of cracks due to the non-uniformity of the internal stress in the cylindrical crimping portion can also be prevented. Therefore, the mechanical strength and the water stopping property of the cylindrical pressure-bonded portion can be further improved.

  According to the aspect of the terminal of the present invention, the width of the heat-affected zone in the wire insertion direction of the neck is 1.0 to 4.0 times the thickness of the heat-affected zone of the neck, and thereby the heat of the neck is reduced. It is possible to further improve the mechanical strength and durability of the neck while obtaining the sealing property in the affected part.

  According to the aspect of the terminal of the present invention, the mechanical strength and durability of the neck can be further improved because the average crystal grain size in the heat-affected zone of the neck is 5 μm or more and 30 μm or less.

It is a perspective view explaining the outline of the terminal concerning an example of an embodiment of the present invention. It is sectional drawing explaining the heat-affected part and the non-heat-affected part in a cylindrical crimping part. It is sectional drawing explaining the heat affected zone and the non-heat affected zone in a neck part. It is explanatory drawing of the test method of the durability of the terminal of this invention.

  Hereinafter, a terminal according to an embodiment of the present invention will be described. First, the structure of a terminal according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating an outline of a terminal according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a heat-affected portion and a non-heat-affected portion in a cylindrical crimping portion. FIG. 3 is a cross-sectional view illustrating a heat-affected zone and a non-heat-affected zone at the neck. FIG. 4 is an explanatory diagram of a method for testing the durability of a terminal according to the present invention.

  As shown in FIG. 1, a terminal 1 according to an embodiment of the present invention includes a cylindrical crimping portion 30 to which an electric wire (not shown) is crimped, and a connector portion to be connected to a mating connection destination (not shown). 20 and a neck portion (transition portion) 40 provided between the tubular crimping portion 30 and the connector portion 20 for bridging and integrally connecting the tubular crimping portion 30 and the connector portion 20.

  The connector section 20 is, for example, a structure having an insertion tab for a male terminal, and a box section that allows insertion of the insertion tab for the male terminal. In the embodiment, the shape of the details of the insertion tab and the box portion of the male terminal is not particularly limited. In the embodiment, an example of a female terminal is shown for convenience of description of the terminal 1.

  The cylindrical crimping part 30 is a part for crimping connection between the terminal 1 and the electric wire. One end of the cylindrical crimping portion 30 has an insertion port 31 into which an electric wire can be inserted, and the other end is connected to the neck portion 40. The cylindrical crimping part 30 extends along the insertion direction of the electric wire. The neck 40 side of the tubular crimping portion 30 is a closed closing portion 32 for preventing intrusion of moisture and the like. Examples of a method for forming the closing portion 32 include laser welding, press molding, and the like. In the present specification, with respect to the boundary between the cylindrical crimping portion 30 and the neck portion 40, a portion from the portion where the electric wire and the terminal 1 are crimped to the insertion opening 31, that is, from the closing portion 32 of the cylindrical crimping portion 30 to the insertion opening. The portion up to 31 is the cylindrical crimping portion 30. If the cylindrical crimping portion 30 of the terminal 1 has a cylindrical shape, a certain effect on the water blocking property can be obtained, so that the shape and size in the longitudinal direction can be appropriately selected according to the use conditions of the terminal 1 and the like. is there.

  The terminal 1 has the tubular crimped portion 30 formed by welding, so that the tubular crimped portion 30 has a heat-affected zone 70 including a welded portion 72 formed by welding. The cylindrical crimping portion 30 forms a crimping portion having a C-shaped cross section by bending a metal member, and then welds the crimping portion at opposite ends thereof to form a cylindrical crimping portion of the metal member. . As described above, the welding for forming the cylindrical crimping portion 30 is performed from the insertion port 31 of the cylindrical crimping portion 30 to the closing portion 32 along the insertion direction of the electric wire. The part 70 extends from the insertion port 31 to the closing part 32. Although the size of the welding region is not particularly limited, for example, in a cross section orthogonal to the wire insertion direction of the cylindrical crimping portion 30, the region of the welding mark has an area ratio of 2 to 5% of the other region. To be welded.

  The heat-affected zone 70 means a portion where the hardness is reduced by welding to 90% or less with respect to the hardness of the non-welded zone which is the non-heat-affected zone 71. The non-heat-affected zone 71 is a portion that is not affected by heat due to welding, and the hardness of the non-heat-affected zone 71 is the hardness of the metal member before welding. As shown in FIG. 2, the hardness of the non-heat-affected zone 71 can be measured by measuring the hardness of the cross section of a region of the cylindrical crimping portion 30 facing the welded portion 72. The average hardness of the heat-affected zone 70 was an average value obtained by measuring the hardness at the center of the thickness of the heat-affected zone 70 at equal intervals of 100 μm along the cylinder.

  In the cylindrical crimping section 30, the metal member and the electric wire forming the cylindrical crimping section 30 are crimped and connected, so that the electric wire and the terminal are mechanically connected and also electrically connected. The cylindrical crimping section 30 can crimp and connect an electric wire by caulking using a caulking jig. By crimping the electric wire to the cylindrical crimping portion 30, a terminal connection structure of the electric wire is formed. By bundling a plurality of such connection structures, for example, an automobile wire harness can be obtained.

  The neck portion 40 is a portion extending from the closing portion 32 of the tubular crimping portion 30 toward the connector portion 20 while maintaining the closed state. The neck portion 40 is in a state where portions of the metal member facing in a direction orthogonal to the insertion direction of the electric wire are in contact with each other. Therefore, the neck portion 40 has a structure in which the cross-sectional area in the direction orthogonal to the insertion direction of the electric wire is smaller than the cross-sectional area of the connector portion 20 and the cylindrical crimping portion 30.

  Since the terminal 1 has the neck 40 formed by welding, the neck 40 has a heat-affected zone 73 including a welded portion 74 formed by welding. The neck 40 is formed by forming a superposed portion of the metal member by bending the metal member, and then moving the superposed portion from the superposed direction of the superposed portion in the width direction in a direction orthogonal to the insertion direction of the electric wire. The whole is welded to form the neck of the metal member. The neck 40 is welded over the entire width direction from the overlapping direction of the overlapping portions, so that the heat-affected zone 73 including the welded portion 74 extends over the entire width of the neck 40. Since the neck portion 40 is welded over the entire width direction, the neck portion 40 is provided with a sealing property.

  The heat-affected zone 73 refers to a portion where the hardness is reduced by welding to 90% or less of the hardness of the non-welded zone, which is the non-heat-affected zone 71. FIG. 3 is a cross-sectional view of the terminal 1 along the region of the welded portion 72 of the cylindrical crimped portion 30 and the non-heat-affected portion 71 facing the welded portion 72 of the cylindrical crimped portion 30 with the neck 40 vertically divided. Show. The width of the heat-affected zone 73 in the neck portion 40 is softened to 90% or less of the hardness of the non-heat-affected zone 71 by measuring the hardness at the center of the thickness of the vertical section in the longitudinal direction. The length of the part. The average hardness of the heat-affected zone 73 of the neck portion 40 was an average value obtained by measuring the hardness at the center of the wall thickness at equal intervals of 100 μm along the width of the heat-affected zone 73.

  The width of the heat-affected zone 73 in the neck 40, that is, the dimension of the heat-affected zone 73 in the wire insertion direction of the neck 40 is not particularly limited. In order to further improve the mechanical strength and durability of the heat-affected zone 73, the thickness of the neck 40 at the portion of the heat-affected zone 73 is preferably 1.0 to 4.0 times, more preferably 2.0 to 3.0 times. The following are particularly preferred.

  Next, a metal member used for the terminal 1 according to the embodiment of the present invention will be described. The metal member used for the terminal 1 is a plate material, and the metal member of the plate material is bent into a predetermined shape, and the bent metal member is welded to form the neck portion 40 and the cylindrical crimping portion 30 to manufacture the terminal 1. be able to. In order to crimp and connect a large-diameter electric wire (for example, an aluminum electric wire) to the terminal 1, it is necessary to use a thick terminal. Therefore, the average thickness of the plate material used for the terminal 1 is increased to 0.38 mm or more and 0.80 mm or less.

  As components of the metal member used for the terminal 1, chromium (Cr) is 0.00 mass% or more and 0.35 mass% or less, phosphorus (P) is 0.00 mass% or more and 0.15 mass% or less, and magnesium (Mg) is 0.1 mass% or less. A copper alloy containing not less than 05 mass% and not more than 0.8 mass%, with the balance being copper (Cu) and unavoidable impurities, is used. By using the metal member, the terminal 1 has an excellent electrical conductivity of 60% IACS or more and 85% IACS or less, so that the electric resistance of the terminal 1 is reduced, and a large current flows through the thick wire. be able to.

  On the other hand, a metal member having excellent electrical conductivity has a high thermal conductivity, so that thermal energy introduced at the time of welding (for example, laser welding) is easily released. Therefore, it is necessary to increase the output of the laser. In addition, it is necessary to increase the output of the laser because the thickness of the metal member is increased. When the output of the laser is increased, the additional elements of the metal member are more likely to evaporate, so that surface defects such as spatter, voids and cracks and internal defects are more likely to occur in the welded portion. In addition, since a metal member having a high thermal conductivity has a high cooling rate, surface defects such as voids and cracks and internal defects are easily generated. However, by using the copper alloy as a metal member, its constituent elements are components that are difficult to evaporate at the time of welding, so even when increasing the output of the laser, at the time of welding and cooling after welding, spatter, voids, Generation of surface defects such as cracks and internal defects (that is, welding defects) can be prevented.

  By using the above copper alloy as the metal member, even if the plate is bent into a thick plate having an average thickness of 0.38 mm or more and 0.80 mm or less, the processing residual stress, particularly, the processing residual stress in the neck portion 40. Can be suppressed, and the occurrence of cracks due to bending can be prevented.

  In the copper alloy, chromium (Cr) and phosphorus (P), which are additive elements, are optional components and need not be added to the copper alloy. However, it is preferable that at least one of chromium (Cr) and phosphorus (P) is contained from the viewpoint that the conductivity is further improved and the occurrence of surface defects and internal defects during welding is more reliably prevented. . When chromium (Cr) is contained, it is particularly preferable that chromium (Cr) is contained at 0.15 mass% or more and 0.35 mass% or less. When phosphorus (P) is contained, phosphorus (P) is 0.005 mass%. % Or more and 0.15 mass% or less is particularly preferable.

  A plating film plated with nickel (Ni) and / or tin (Sn) may be provided on the surface of the copper alloy as needed. When a plating film is formed on the surface of the copper alloy, the plating film contains nickel (Ni) and / or tin (Sn) as essential components. These plating films include, for example, a tin (Sn) plating film and a plating film composed of nickel (Ni) plating and tin (Sn) plating, which are base platings. Since the surface of the copper alloy forming the terminal 1 is covered with the plating film, the terminal 1 is provided with corrosion resistance and contributes to the improvement of the durability of the terminal 1. The plating film may be an alloy plating film containing copper (Cu), silver (Ag), or the like as an optional component, if necessary, and further provided with copper (Cu) plating and silver (Ag) plating. A plating film may be used. The thickness of the plating film can be appropriately adjusted depending on the use conditions of the terminal 1 and the like, and includes, for example, 0.3 μm (μm) to 1.2 μm (μm).

  In the terminal 1, the ratio of the average hardness (Vickers hardness) of the non-heat-affected zone 71 to the average hardness (Vickers hardness) of the heat-affected zone 73 in the neck 40 is 1.1 or more and 1.8 or less. ing. The ratio of the average hardness of the non-heat-affected zone 71 to the average hardness of the heat-affected zone 73 in the neck 40 is 1.1 or more and 1.8 or less. By reducing the difference in hardness, the unevenness of internal stress in the neck 40 due to welding can be suppressed. Since the unevenness of the internal stress in the neck 40 can be suppressed, it is possible to prevent the occurrence of cracks in the neck 40 and to improve the durability of the neck 40. The ratio of the average hardness of the non-heat-affected zone 71 to the average hardness of the heat-affected zone 73 of the neck portion 40 is preferably closer to 1 from the viewpoint of more reliably suppressing the non-uniformity of the internal stress caused by welding, For example, the upper limit of the ratio is preferably 1.7. The measurement position of the hardness of the non-heat-affected zone 71 is not particularly limited, whether the neck portion 40 or the cylindrical crimping portion 30.

  The average hardness (Vickers hardness) of the heat-affected zone 73 of the neck 40 is, for example, 80 (Hv) to 150 (Hv). When the neck portion 40 has the non-heat-affected zone 71, the average hardness (Vickers hardness) of the non-heat-affected zone 71 is, for example, 100 (Hv) to 200 (Hv). The ratio of the average hardness of the non-heat-affected zone 71 to the average hardness of the heat-affected zone 73 of the neck 40 is determined by selecting the amount of energy to be input when welding the copper alloy portion corresponding to the neck 40. Can be adjusted.

  Regarding the metal member used for the terminal 1, the average crystal grain size in the heat-affected zone 73 of the neck 40 is not particularly limited, but is preferably 5 μm or more and 30 μm or less, and more preferably 9 μm from the viewpoint of further improving the mechanical strength and durability of the neck. It is particularly preferable that the thickness be at least 27 μm. The average crystal particle diameter can be measured by an intersection method according to JIS H0501, H0502.

  The ratio of the average hardness of the non-heat-affected zone 71 to the average hardness of the heat-affected zone 70 in the cylindrical crimping section 30 is not particularly limited. However, the occurrence of cracks due to the non-uniformity of the internal stress in the cylindrical crimping portion 30 as well as the neck portion 40 is also prevented, and the mechanical strength and waterproofness of the cylindrical crimping portion 30 are further improved. The ratio of the average hardness of the non-heat-affected zone 71 to the average hardness of the heat-affected zone 70 in the portion 30 is preferably 1.1 or more and 1.7 or less. The ratio of the average hardness of the non-heat-affected zone 71 to the average hardness of the heat-affected zone 70 in the cylindrical crimped portion 30 is set to 1 from the viewpoint of more reliably suppressing the non-uniformity of the internal stress caused by welding. The lower the ratio, the more preferable. For example, the upper limit of the ratio is particularly preferably 1.6. The measurement position of the hardness of the non-heat-affected zone 71 in the tubular crimping section 30 is not particularly limited.

  The average hardness (Vickers hardness) of the heat-affected zone 70 of the cylindrical pressure-bonded portion 30 is, for example, 80 (Hv) to 150 (Hv), and the average hardness (Vickers hardness) of the non-heat-affected zone 71 is , For example, 100 (Hv) to 200 (Hv). The ratio of the average hardness of the non-heat-affected zone 71 to the average hardness of the heat-affected zone 70 in the cylindrical crimping section 30 is also input when welding the copper alloy portion corresponding to the cylindrical crimping section 30. It can be adjusted by selecting the amount of energy.

  Next, an example of a method for manufacturing the terminal 1 will be described. First, a metal member made of a plate-like copper alloy having the above-described components is processed into a predetermined planar shape corresponding to a shape in which the terminal 1 is developed. As a processing method, for example, a punching process is exemplified. By bending one end of the metal member processed into a predetermined planar shape, a crimping portion having a C-shaped cross section in a direction perpendicular to the wire insertion direction is formed. Thereafter, the crimping portion is welded at opposite ends thereof to form a cylindrical crimping portion of the metal member, that is, a portion corresponding to the cylindrical crimping portion 30 of the terminal 1. Next, an overlapping portion of the metal member is formed by bending an intermediate portion of the metal member processed into a predetermined planar shape from right and left along the insertion direction of the electric wire. Then, from the overlapping direction of the overlapping portion, the overlapping portion is welded in a direction perpendicular to the insertion direction of the electric wire and over the entire width direction of the overlapping portion to form a neck of the metal member, that is, the terminal 1. Is formed at a position corresponding to the neck 40. Then, the connector part 20 is formed by bending the other end of the metal member processed into a predetermined planar shape.

Examples of the core wire of the electric wire include a copper alloy wire and an aluminum alloy wire. As a specific example of the aluminum alloy core wire, iron (Fe) is about 0.2% by mass, copper (Cu) is about 0.2% by mass, magnesium (Mg) is about 0.1% by mass, and silicon (Si) is It is possible to use an aluminum core wire of about 0.04% by mass, the balance being aluminum (Al) and unavoidable impurities. Other alloy compositions include about 1.05% by mass of Fe, about 0.15% by mass of Mg, about 0.04% by mass of Si, the balance being Al and unavoidable impurities, and about 1.0% by mass of Fe. , About 0.04 mass% of Si, the balance being Al and unavoidable impurities, about 0.2 mass% of Fe, about 0.7 mass% of Mg, about 0.7 mass% of Si, the balance of Al and Inevitable impurities can be used. These may further contain alloy elements such as Ti, Zr, Sn, and Mn. By using a metal wire having such a composition, a core wire having a large diameter in the form of a stranded wire having a total cross-sectional area of ^{2 to} 13 mm ² and a number of wires of 7 to 171 can be used. As a coating material used as the insulating coating of the core wire, for example, a material mainly containing polyelefin such as PE or PP, a material mainly containing PVC, or the like can be used.

  Next, examples of the present invention will be described. However, the present invention is not limited to the following examples unless departing from the gist.

Examples 1 to 5, Comparative Examples 1 to 3
Method of Manufacturing Terminal A terminal of the embodiment having the above-described configuration was manufactured using a metal member made of a copper alloy shown in Table 1 below. Specifically, a plate-shaped copper alloy having the components and plate thicknesses shown in Table 1 below was processed by press punching into a planar shape corresponding to the developed shape of the terminal. One end of a plate-shaped copper alloy processed into a predetermined planar shape was bent to form a crimping portion having a C-shaped cross section in a direction orthogonal to the wire insertion direction. Next, an overlapped portion of the copper alloy was formed by bending an intermediate portion of the plate-shaped copper alloy processed into a predetermined planar shape from the left and right along the insertion direction of the electric wire. Next, the connector part was formed by bending the other end of the metal member processed into a predetermined planar shape. Thereafter, a laser beam having a predetermined energy amount is applied to both ends of the crimped portion and laser-welded to form a cylindrical crimped portion of the terminal. Then, a laser beam having a predetermined energy amount was irradiated over the entire width direction of the overlapped portion in a direction perpendicular to the insertion direction of the terminal and was welded by laser to form a neck portion of the terminal. The diameter of the cylindrical crimping portion in the direction perpendicular to the wire insertion direction was 0.5 mm ² . Thereafter, the aluminum electric wire was inserted into the cylindrical crimping portion and crimped so that the cross-sectional area of the aluminum electric wire was 0.2 mm ² .

Experimental conditions for laser welding are as follows.
・ Used laser light source: Semiconductor laser
-Sweep irradiation using a galvano scanner (non-telecentric)-Laser beam output: 800 to 1000W
-Sweep speed: 50 to 500 mm / sec.
・ Laser beam irradiation (spot size: 30 μm) with just focus on all conditions

(1) Measuring method of tensile strength A sample of No. 13B was prepared with an NC milling machine and measured using "AG-100KND" manufactured by Shimadzu Corporation.

(2) Method of Measuring Conductivity A rectangular sample having a width of 10 mm and a length of 200 mm was prepared and measured by a four-terminal method.

(3) The ratio of the average hardness of the non-heat-affected zone to the average hardness of the heat-affected zone in the cylindrical pressure-bonded portion (hardness of the non-heat-affected zone / hardness of the cylindrical heat-affected zone)
The hardness of the heat-affected zone and the hardness of the non-heat-affected zone were measured by the Vickers test method based on JIS Z 2244.
The heat-affected zone means a portion where the hardness is reduced by welding to 90% or less of the hardness of the non-welded portion which is the non-heat-affected zone.
The average hardness of the heat-affected zone of the cylindrical pressure-bonded portion was an average value of the heat-affected portions of the cylindrical pressure-bonded portion measured at equal intervals of 100 μm at the center of the plate thickness.
In addition, the average hardness of the non-heat-affected zone is such that the central portion of the thickness of the region opposite to the welded portion of the cylindrical crimped portion at an interval of 100 μm among the cylindrical crimped portions separated from the neck welded portion by 5 mm or more. The measured average value was used.

(4) The dimension of the heat-affected zone in the direction of wire insertion of the neck relative to the thickness of the neck (width of the heat-affected zone in the direction of wire insertion of the neck / thickness of the neck)
The thickness of the neck was determined by observing the cross section of the neck with an optical microscope, measuring the thickness at three locations, and taking the average value.
As shown in FIG. 3, the width of the heat-affected zone at the neck is measured in the longitudinal direction by measuring the hardness at the center of the thickness of the vertical section of the neck, and is 90% or less of the hardness of the non-heat-affected zone. The length of the softened portion was set.

(5) The ratio of the average hardness of the heat-affected zone to the average hardness of the heat-affected zone at the neck (hardness of the non-heat-affected zone / hardness of the neck heat-affected zone)
The average hardness of the heat-affected zone at the neck was an average value obtained by measuring the hardness at the center of the wall thickness at equal intervals of 100 μm along the width of the heat-affected zone.
In addition, the average hardness of the non-heat-affected zone is such that the center part of the thickness of the region opposite to the welded portion of the cylindrical crimped portion in the cylindrical crimped portion separated from the welded portion of the neck by 5 mm or more is equally spaced by 100 μm. It was the average value measured in.

(6) Average crystal particle diameter of heat-affected zone at neck The average crystal particle diameter was measured by a crossing method according to JIS H0501 and H0502. Specifically, a straight line parallel to the wire insertion direction was drawn on the photographed photo, and the number of grain boundaries intersecting the straight line was measured.

(7) Durability (number of flexures before fatigue failure)
As shown in FIG. 4, the terminal crimping portion is pinched and fixed to a fixing member, and the terminal connector is connected so that the elongation of the heat-affected portion of the neck in the wire insertion direction is 0.05%. The part was reciprocated 10 million times in the direction perpendicular to the wire insertion direction, and the presence or absence of breakage such as crack generation at the neck was visually evaluated.
：: No destruction such as cracks occurred ×: Destruction such as cracks occurred

(8) Water stoppage An electric wire covered with a covering material was crimp-connected to the tubular crimping portion of the terminal such that the end extended 11 mm from the insertion opening of the tubular crimping portion. Thereafter, a container filled with water was prepared, the terminal to which the electric wire was crimped was connected, and the terminal was completely immersed in water up to the insertion port. Next, the air pressure was gradually increased from the end of the electric wire that was not immersed in water, and air pressure of 50 kPa was applied for 30 seconds to visually confirm that there was no air leak. Thereafter, the terminal to which the wire was crimped was taken out of the container, and after 120 hours at 120 ° C., a leak test was performed in the same manner as described above. When no leak was observed in the leak test after elapse of 120 hours at 120 ° C., it was evaluated as 認 め, and when leak was observed, as ×.

  The evaluation results are shown in Table 1 below.

  From Table 1, it is found that Ni and / or Ni are contained in a copper alloy containing 0.05 mass% to 0.8 mass% of Mg, having a conductivity of 60% IACS to 85% IACS, and a plate thickness of 0.38 mm to 0.80 mm. Alternatively, in Examples 1 to 5, in which the hardness of the non-heat-affected zone / the hardness of the neck heat-affected zone is 1.1 to 1.8 using a metal member plated with Sn, the durability and mechanical properties of the neck are It was possible to obtain a terminal having excellent characteristics and excellent water stopping properties. Further, in Examples 1 to 5, the hardness of the non-heat-affected zone / the hardness of the heat-affected zone of the tube portion crimping portion is 1.1 to 1.7, and cracks and the like also occur in the tube portion crimping portion. As a result, a terminal having excellent mechanical strength and waterproofness was obtained. Further, in Examples 1 to 5, the width of the heat-affected zone in the wire insertion direction of the neck is 1 to 4 times the thickness of the heat-affected zone of the neck, and the sealing property of the heat-affected zone of the neck is obtained. At the same time, it was able to contribute to reliably improving the mechanical strength and durability of the neck. In Examples 1 to 5, the average crystal grain size in the heat-affected zone of the neck was 5 μm or more and 30 μm or less, which could contribute to further improving the mechanical strength and durability of the neck.

  On the other hand, in Comparative Examples 1 and 2 in which the copper alloy does not contain Mg and the hardness of the non-heat-affected zone / hardness of the neck heat-affected zone is 2.1 to 2.9, the durability at the neck and the terminal Could not be obtained. In Comparative Example 3 using a metal material containing 0.1 mass% of Mg in a copper alloy, the hardness of the non-heat-affected zone / the hardness of the neck heat-affected zone was 2.7, and the durability at the neck was also high. Properties and water stopping properties of the terminals could not be obtained.

  The terminal of the present invention prevents the occurrence of cracks in the neck even if a thick metal member having a small volume resistivity is used for crimping connection of a large-diameter electric wire, and the mechanical strength and durability of the neck are improved. Since it is possible to obtain a terminal excellent in water resistance and water blocking property, it is highly useful, for example, in the field of automobile wire harnesses using large-diameter electric wires, that is, in the field of automobile terminals.

DESCRIPTION OF SYMBOLS 1 Terminal 20 Connector part 30 Cylindrical crimping part 40 Neck 70 Heat-affected part 71 of a tube part crimping part Non-heat-affected part 72 Welding part 73 of a tube part crimping part Heat-affected part 74 of a neck part

Claims (8)

A tubular crimping portion to which an electric wire is crimped and connected, a connector portion connected to a mating connection destination, and a neck portion provided between the tubular crimping portion and the connector portion; However, the heat-affected zone formed by welding and the heat-affected zone has a non-heat-affected zone that is a different region, the neck portion is a terminal having the heat-affected zone formed by welding,
The terminal has a Cr content of 0.00 mass% or more and 0.35 mass% or less, a P content of 0.00 mass% or more and 0.15 mass% or less, a Mg content of 0.05 mass% or more and 0.8 mass% or less, and a balance of Cu and inevitable impurities. It is made of a metal member having an average thickness of 0.38 mm or more and 0.80 mm or less, and a conductivity of 60% IACS or more and 85% IACS or less,
A terminal in which a ratio of an average hardness of the non-heat-affected zone to an average hardness of the heat-affected zone in the neck is 1.1 or more and 1.8 or less.   The terminal according to claim 1, wherein Cr is 0.15% by mass or more and 0.35% by mass or less.   The terminal according to claim 1, wherein P is 0.005 mass% or more and 0.15 mass% or less.   The ratio of the average hardness of the non-heat-affected zone to the average hardness of the heat-affected zone in the cylindrical crimped portion is 1.1 or more and 1.7 or less. Terminal described.   5. The neck according to claim 1, wherein a width of the heat-affected zone in the wire insertion direction of the neck is 1.0 to 4.0 times a thickness of the heat-affected zone of the neck. 6. Terminal.   The terminal according to any one of claims 1 to 5, wherein an average crystal grain diameter in the heat-affected zone of the neck is 5 µm or more and 30 µm or less.   The terminal according to any one of claims 1 to 6, wherein the terminal is formed from the metal member plated with Ni and / or Sn.   When one end of the terminal is reciprocated in the direction perpendicular to the wire insertion direction so that the elongation percentage of the heat-affected zone of the neck in the wire insertion direction becomes 0.05%, the terminal is reciprocated 10 million times. The terminal according to any one of claims 1 to 7, wherein the neck portion is not broken even when the terminal portion is broken.

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