JP2017027705A - Connector terminal and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connector terminal capable of suppressing exposure of a metal base material caused by plating crack at a bend.SOLUTION: A connector terminal 1 has a bend 11 formed by bending. The connector terminal 1 has a metal base material 101 composed of a Cu-Fe-based alloy, a base plating layer 102 formed by heat-treating a Ni-based plating layer formed on the surface of the metal base material 101, and a surface plating layer 103 formed on the surface of the base plating layer 102.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a connector terminal and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, in the field of vehicles such as automobiles, connector terminals are used for connectors such as board connectors and relay connectors applied to PCBs (Print Circuit Boards) (see Patent Document 1). The connector terminal generally has a bent portion formed by bending. As this type of connector terminal, for example, one having a metal base material made of a copper alloy such as brass and a surface plating layer made of an Sn plating layer formed on the surface of the metal base material is known.

JP 2004-319338 A

  In recent years, there has been a demand for a connector terminal that has higher rigidity and can reduce material costs in order to reduce the weight, size, and cost of the entire connector. Therefore, it is conceivable to use a Cu—Fe alloy in which Fe is added to Cu as a metal base material of a connector terminal as a copper alloy having high material strength and low material cost.

  However, a metal base material made of a Cu—Fe-based alloy has a problem that Fe contained in the metal base material is eluted by contact with the plating solution when the surface plating layer is formed. In order to prevent this, it is conceivable to form a Ni plating layer as a base plating layer before forming the surface plating layer.

  However, Ni plating is harder than Sn plating or the like. Therefore, after the Ni plating process, when the metal base material is bent and a bent portion is formed, plating cracks occur in the bent portion and the metal base material is exposed. If the plating crack in the bent portion is left as it is, rust is likely to occur in a corrosive atmosphere or the like because Fe is contained in the metal base material. Rust is not preferable because it causes a decrease in terminal strength of the connector terminal and an increase in contact electrical resistance.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a connector terminal capable of suppressing exposure of a metal base material due to plating cracks in a bent portion.

One aspect of the present invention is a connector terminal having a bent portion formed by bending,
A metal base material made of a Cu-Fe alloy;
A base plating layer formed by heat-treating a Ni-based plating layer formed on the surface of the metal base material;
A surface plating layer formed on the surface of the base plating layer;
It is in the terminal for connectors having.

Another aspect of the present invention is a method of manufacturing the connector terminal,
A first plating step of forming the Ni-based plating layer on the surface of the wire material made of the Cu-Fe-based alloy or the surface of the punched body of the plate material made of the Cu-Fe-based alloy;
A heat treatment step of forming the base plating layer by heat-treating the Ni-based plating layer;
A second plating step for forming the surface plating layer on the surface of the base plating layer;
Bending process to bend the obtained terminal material to form the bent portion,
In the manufacturing method of the connector terminal which has.

  The connector terminal has a base plating layer formed by heat-treating a Ni-based plating layer formed on the surface of the metal base material. This base plating layer is excellent in extensibility compared with the base plating layer which consists of the Ni plating layer with the electrodeposition state which is not heat-processed. This is considered to be because Ni-plated particles grow from the electrodeposited structure by heat treatment and change to a metal structure in which improvement in elongation (softening) is observed. Therefore, when the bent portion is formed by bending, the connector terminal is less likely to cause plating cracks in the base plating layer. Therefore, the connector terminal can suppress exposure of the metal base material due to plating cracks in the bent portion. As a result, the connector terminal is less likely to rust in a corrosive atmosphere or the like, and can suppress a decrease in terminal strength and an increase in contact electrical resistance due to rust.

  The manufacturing method of the connector terminal includes the steps described above. Therefore, it is possible to suitably manufacture the connector terminal that can suppress the exposure of the metal base material caused by the plating crack in the bent portion.

1 is a schematic external view of a connector terminal of Example 1. FIG. FIG. 3 is an explanatory diagram schematically showing a part of a cross section of the connector terminal according to the first embodiment. It is a scanning electron micrograph of test piece 1S in an experimental example. It is a scanning electron micrograph of the test piece 2S in an experiment example.

  The connector terminal will be described. The connector terminal can be used, for example, as a board connector terminal applied to a PCB.

  The connector terminal has a bent portion formed by bending. Specifically, the bent portion can be a 90 ° bent portion formed by 90 ° bending. In the case of having a base plating layer made of an Ni plating layer that has not been heat-treated, if it is bent by 90 °, cracking of the base plating layer tends to occur at the bent portion. On the other hand, since the connector terminal has a base plating layer formed by heat-treating the Ni-based plating layer, it is easy to suppress cracking of the base plating layer in the bent portion even when it is bent by 90 °. . Therefore, according to this structure, the usefulness as a board | substrate connector terminal in which a 90 degree bending process is given increases. The connector terminal can have, for example, an “L-shaped” terminal shape. Moreover, the said connector terminal can exhibit pin shape, for example.

  In the connector terminal, the metal base material is made of a Cu-Fe alloy. Specifically, the Cu—Fe-based alloy can contain 10 to 70% by mass of Fe. More specifically, the Cu—Fe-based alloy can contain 10 to 70% by mass of Fe, with the balance being Cu and inevitable impurities.

  Cu-Fe-based alloys tend to have higher strength as the Fe content increases. Therefore, the intensity | strength requested | required of the connector terminal can fully be satisfied by making Fe content into 10 mass% or more. Moreover, it becomes easier to reduce material cost than the copper alloy currently used for the terminal for connectors by making Fe content into 10 mass% or more. Therefore, from the viewpoint of increasing the terminal strength and further reducing the material cost, the Fe content is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more. be able to.

  On the other hand, Fe has a lower conductivity than Cu. Therefore, when the Fe content is excessively large, the conductivity of the connector terminal may be deteriorated. Further, when the Fe content is excessively increased, the bending workability is deteriorated, so that there is a high possibility that the metal base material is cracked along with the bending process. From these viewpoints, the Fe content is preferably 70% by mass or less, more preferably 65% by mass or less, and still more preferably 60% by mass or less.

  In the connector terminal, the base plating layer is formed by heat-treating a Ni-based plating layer formed on the surface of the metal base material. Here, specifically, the Ni-based plating layer can be composed of a Ni plating layer and / or a Ni alloy plating layer.

  The base plating layer should just cover the bending part at least. The base plating layer may cover the entire surface of the terminal or may not cover the entire surface of the terminal.

  Specifically, the thickness of the base plating layer is preferably 0.5 to 2 μm, more preferably 0.5 to 1.5 μm, and further preferably 0.5 to 1.2 μm, from the viewpoint of corrosion resistance, cost, and the like. can do.

  In the connector terminal, the surface plating layer may be composed of one layer or two or more layers. The surface plating layer is formed of a plating type different from that of the base plating layer. The surface plating layer can be, for example, a Sn-based plating layer. Specifically, the Sn-based plating layer can be composed of a Sn plating layer and / or a Sn alloy plating layer. The Sn-based plating layer has an extremely thin oxide film on the surface. Therefore, oxidation of internal Sn is suppressed. In addition, when the connector terminal is fitted to the mating terminal, the very thin oxide film is torn, so that the Sn-based plating under the oxide film can reliably contact the surface plating of the mating terminal. The Sn-based plating layer is advantageous for keeping the contact electric resistance low. The Sn-based plating layer also has an effect of protecting the metal base material from corrosion and rust. Therefore, according to this configuration, it is possible to ensure the effect of suppressing the increase in contact electrical resistance and suppressing the decrease in terminal strength due to corrosion, rust, or the like. The surface plating layer may be subjected to a reflow process.

  A method for manufacturing the connector terminal will be described. The manufacturing method of the connector terminal includes the first plating step, the heat treatment step, the second plating step, and the bending step.

  In the first plating step, specifically, the wire and the punched body have not yet been formed with a bent portion by bending. Moreover, specifically, a wire and a punching body are formed in the magnitude | size used as a predetermined terminal shape, for example after a bending process.

  As heat processing temperature in a heat processing process, 750-850 degreeC etc. can be illustrated, for example. Moreover, as heat processing time, 0.5 to 3 hours etc. can be illustrated, for example. The heat treatment can be performed in an air atmosphere, a nitrogen atmosphere, a hydrogen reducing atmosphere, or the like. From the viewpoint of suppressing oxidation of the Ni-based plating, it can be preferably performed in a reducing atmosphere such as a hydrogen reducing atmosphere. In addition, heat processing can be implemented by the heat processing line provided continuously with the plating line for forming Ni type plating layer, for example. Moreover, heat processing can also be implemented by batch processing, after forming a Ni-type plating layer.

  In the bending step, specifically, for example, a bent portion can be formed by bending a terminal material press-fitted into the housing of the connector with a press.

  In addition, each structure mentioned above can be arbitrarily combined as needed, in order to acquire each effect etc. which were mentioned above.

  Hereinafter, a connector terminal of an example and a manufacturing method thereof will be described with reference to the drawings.

Example 1
The connector terminal of Example 1 will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the connector terminal 1 has a bent portion 11 formed by bending. In this example, the connector terminal 1 specifically has an “L-shaped” terminal shape and is used as a board connector terminal applied to a PCB. More specifically, the connector terminal 1 has a fitting portion 12 in which one end portion is fitted to the mating terminal with the bent portion 11 interposed therebetween, and the other end portion is electrically connected to the through hole of the board connector. The connecting portion 13 is connected to the other. In this example, the bent portion 11 is a 90 ° bent portion formed by 90 ° bending.

  The connector terminal 1 includes a metal base material 101, a base plating layer 102, and a surface plating layer 103. The metal base material 101 is made of a Cu—Fe based alloy. In this example, the Cu-Fe alloy specifically contains 90 to 30% by mass of Cu and 10 to 70% by mass of Fe. The base plating layer 102 is formed by heat-treating a Ni-based plating layer formed on the surface of the metal base material 101. In this example, the Ni-based plating layer is a Ni plating layer. The thickness of the base plating layer 102 can be set to 1 μm, for example. The surface plating layer 103 is formed on the surface of the base plating layer 102. In this example, the surface plating layer 103 is a Sn plating layer. The Sn plating layer is subjected to a reflow process.

  Next, the effect of the connector terminal of this example will be described.

  The connector terminal 1 of this example has a base plating layer 102 formed by heat-treating a Ni-based plating layer formed on the surface of a metal base material 101. This base plating layer 102 is excellent in extensibility compared with the base plating layer which consists of the Ni plating layer with the electrodeposition state which is not heat-processed. This is considered to be because Ni-plated particles grow from the electrodeposited structure by heat treatment and change to a metal structure in which improvement in elongation (softening) is observed. Therefore, in the connector terminal 1 of this example, when the bent portion 11 is formed by bending, plating cracks are unlikely to occur in the base plating layer 102. Therefore, the connector terminal 1 of this example can suppress the exposure of the metal base material 101 due to the plating crack in the bent portion 11. As a result, the connector terminal 1 of this example is less likely to rust in a corrosive atmosphere or the like, and can suppress a decrease in terminal strength and an increase in contact electrical resistance due to rust.

(Example 2)
A method for manufacturing the connector terminal according to the second embodiment will be described. The manufacturing method of the connector terminal of this example includes a first plating step, a heat treatment step, a second plating step, and a bending step. In addition, below, it demonstrates as a method of manufacturing the terminal 1 for connectors of Example 1. FIG.

  In the first plating step, a Ni-based plating layer is formed on the surface of a wire made of a Cu-Fe-based alloy or a surface of a punched body of a plate material made of a Cu-Fe-based alloy. In this example, the Ni-based plating layer is formed by electrolytic plating.

  In the heat treatment step, the base plating layer 102 is formed by heat-treating the Ni-based plating layer. In this example, the heat treatment temperature is 750 to 850 ° C., for example. The heat treatment time is, for example, 0.5 to 3 hours. Note that the heat treatment is performed in a hydrogen reduction atmosphere.

  In the second plating step, the surface plating layer 103 is formed on the surface of the base plating layer 102. In this example, the surface plating layer 103 is specifically a Sn plating layer. The Sn plating layer is formed by an electrolytic plating method and then subjected to a reflow process.

  In the bending process, the obtained terminal material is subjected to a bending process to form the bent portion 11. In this example, the 90 ° bent portion is formed by bending the terminal material held in the connector housing by press fitting or the like with a press.

  Next, the effect of the manufacturing method of the connector terminal of this example will be described.

  The manufacturing method of the connector terminal includes the steps described above. Therefore, the connector terminal 1 that can suppress the exposure of the metal base material 102 due to the plating crack in the bent portion 11 can be preferably manufactured.

<Experimental example>
Hereinafter, it demonstrates more concretely using an experiment example.

<Production of connector terminals>
After bending, which will be described later, a Ni plating layer (thickness 1 μm) was formed on the surface of a wire (diameter 0.6 mm) having a predetermined terminal shape using an electrolytic plating method. The wire contains 50% by mass of Fe, with the balance being Cu and inevitable impurities.

  Next, the wire having the Ni plating layer was heat-treated at 850 ° for 2 hours in a hydrogen reduction atmosphere to form a base plating layer (thickness 1 μm).

  Next, Sn plating was performed on the surface of the base plating layer using an electrolytic plating method, and then a reflow process was performed to form a Sn plating layer (thickness: 1.2 μm). Next, a terminal material having a length of 30 mm was cut out from the wire. Then, one end of the terminal material was press-fitted into the housing of the board connector. Thereafter, a 90 ° bent portion was formed by bending an intermediate portion of the terminal material exposed from the housing to 90 °. As a result, a connector terminal of Sample 1 was obtained.

  In producing the connector terminal of Sample 1, the connector terminal of Sample 2 was obtained in the same manner except that the Ni plating layer in the electrodeposited state was used as the base plating layer as it was without heat-treating the Ni plating layer.

<Scanning electron microscope observation of the bent surface>
A test piece 1S for SEM observation was produced in the same manner except that the Sn plating layer was not formed in the production of the connector terminal of Sample 1. In addition, a test piece 2S for SEM observation was prepared in the same manner except that the Sn plating layer was not formed in the production of the connector terminal of Sample 2.

  Next, the outer surface of the 90 ° bent portion of each test piece was observed with a scanning electron microscope. In addition, according to the test piece 1S, the base plating layer formed by heat-treating the Ni plating layer in the 90 ° bent portion can be observed. On the other hand, according to the test piece 2S, it is possible to observe a base plating layer made of an electrodeposited Ni plating layer in a 90 ° bent portion.

  As shown in FIG. 3, in the test piece 1 </ b> S, no plating crack was observed in the base plating layer in the 90 ° bent portion. This is because the extensibility of the base plating layer was improved and the ductility was increased, so that the base plating layer was not broken by the 90 ° bending process. On the other hand, as shown in FIG. 4, in the test piece 2S, many plating cracks were confirmed in the base plating layer in the 90 ° bent portion. This is because the Ni plating layer is not heat-treated, and therefore the base plating layer has poor stretchability and cannot withstand 90 ° bending. Note that the horizontal streaks shown in FIG. 3 are the surface irregularities of the metal base material appearing on the surface of the base plating layer and are not plating cracks.

  According to the above results, it was confirmed that a connector terminal capable of suppressing the exposure of the metal base material due to the plating crack in the bent portion was obtained.

  As mentioned above, although the Example of this invention was described in detail, this invention is not limited to the said Example, A various change is possible within the range which does not impair the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Connector terminal 11 Bending part 101 Metal base material 102 Base plating layer 103 Surface plating layer

Claims (4)

A connector terminal having a bent portion formed by bending,
A metal base material made of a Cu-Fe alloy;
A base plating layer formed by heat-treating a Ni-based plating layer formed on the surface of the metal base material;
A surface plating layer formed on the surface of the base plating layer;
A connector terminal.   The connector terminal according to claim 1, wherein the surface plating layer is a Sn-based plating layer.   The connector terminal according to claim 1, wherein the bent portion is a 90 ° bent portion formed by 90 ° bending. It is a manufacturing method of the terminal for connectors given in any 1 paragraph of Claims 1-3,
A first plating step of forming the Ni-based plating layer on the surface of the wire material made of the Cu-Fe-based alloy or the surface of the punched body of the plate material made of the Cu-Fe-based alloy;
A heat treatment step of forming the base plating layer by heat-treating the Ni-based plating layer;
A second plating step for forming the surface plating layer on the surface of the base plating layer;
Bending process to bend the obtained terminal material to form the bent portion,
The manufacturing method of the terminal for connectors which has.