JP2016207495A - Electrical connection component, terminal pair and connector pair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical connection component capable of maintaining a low contact resistance over a long period.SOLUTION: An electrical connection component 1 is used by bringing a first contact part 33 provided in a first component 3 into contact with a second contact 23 provided in a second component 2. The first contact 33 has a first base metal 31 composed of a metal, and a first CuSn alloy layer 32 existing on the first base metal 31, and has a substantially spherical shape bulged out to the second contact 23 side. The second contact 23 has a second base metal 21 composed of a metal, and a second CuSn alloy layer 22 existing on the second base metal 21, and has a substantially tubular shape. The radius of curvature r (mm) of the first contact 33, and the contact load F(N) in a state where the first CuSn alloy layer 32 and the second CuSn alloy layer 22 are abutting, satisfy the following formulae (1) and (2); Fr≥0.8 ... (1), F≤5 ...(2).SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrical connection component, a terminal pair having the electrical connection component, and a connector pair.

  Electrical connection parts such as male terminals and female terminals often have a Sn (tin) plating film on the surface of a substrate made of a Cu (copper) alloy. However, since the electrical connection component has a relatively soft Sn plating film on the surface, there is a problem that the friction coefficient when the contact portion slides is large and the insertion force at the time of fitting is increased. Therefore, a technique is disclosed in which a Cu plating layer and a Sn plating layer are sequentially laminated on a substrate made of a Cu alloy, and then a reflow process is performed to form a CuSn alloy layer harder than pure Sn ( For example, Patent Document 1). In addition, a technique of providing a Ni (nickel) layer between a base material and a CuSn alloy layer is also known for the purpose of suppressing diffusion of a metal element from the base material during use of an electrical connection component (for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 01-30122 JP 2003-293187 A

  Conventionally, when an electrical connection component is used for a long time in an environment where vibration or impact is applied, there has been a problem that the contact resistance at the contact portion increases with time. It is considered that the increase in contact resistance under a vibration environment is caused by the following mechanism. For example, in the case of an electrical connection component in which an Sn layer is formed on a CuSn alloy layer, due to a contact load applied between the components, the contact portion between one component (for example, male terminal) and the other component (for example, female terminal) A relatively soft Sn layer is easily eliminated. Therefore, normally, the CuSn alloy layers are brought into contact with each other at the contact portion, whereby the electrical connection component becomes conductive.

  When vibration or impact is applied to the electrical connection component, depending on the size, the position of one component in the contact portion may be displaced relative to the other component, and the components may slide. When sliding is repeatedly applied to the contact portion, the portions of the CuSn alloy layer that are in contact with each other are oxidized, and a complex oxide of Cu and Sn is deposited on the contact portion and in the vicinity thereof. Since this complex oxide is insulative, it is considered that the contact resistance of the electrical connection component increases.

  In order to suppress an increase in contact resistance under a vibration environment, it is effective to increase the contact load at the contact portion. For example, in a conventional automobile terminal, by setting the contact load to 10 N or more, it is possible to suppress the above-described misalignment and formation of complex oxides at the contact portion.

  However, in recent years, with the miniaturization of electrical connection parts, the above problems are becoming apparent again. Since it is difficult to increase the strength of structural parts structurally or materially for small electrical connection parts, there is a limit to increasing the contact load. Therefore, it is difficult for a small electrical connection component to suppress an increase in contact resistance.

  The present invention has been made in view of such a background, and an object of the present invention is to provide an electrical connection component that can maintain a low contact resistance over a long period of time.

One aspect of the present invention is an electrical connection component that is used by contacting a first contact portion provided in a first component and a second contact portion provided in a second component,
The first contact portion has a first base material made of metal and a first CuSn alloy layer existing on the first base material, and has a substantially hemispherical shape bulging toward the second contact portion side. And
The second contact portion has a second base material made of metal and a second CuSn alloy layer present on the second base material, and has a substantially flat plate shape,
The contact load F [of the first contact portion and the second contact portion in a state where the curvature radius r [mm] of the first contact portion is in contact with the first CuSn alloy layer and the second CuSn alloy layer. N] satisfies the following formula (1) and the following formula (2).
F ^1/3 r ^-2/3 ≧ 0.8 (1)
F ≦ 5 (2)

  The electrical connection component includes the first contact portion having a substantially hemispherical shape and the second contact portion having a substantially flat plate shape, and is configured to satisfy the formula (1) and the formula (2). Has been. Accordingly, a sufficiently large stress can be applied to the contact portion between the first contact portion and the second contact portion without increasing the contact load F. As a result, a low contact resistance can be easily maintained over a long period of time even in a use environment where vibration or the like is applied. This effect is apparent from experimental examples described later.

  Further, the electrical connection component does not need to increase the contact load F in order to suppress an increase in contact resistance. Therefore, the electrical connection component can be easily downsized.

  As described above, the electrical connection component can be easily downsized while suppressing an increase in contact resistance. Therefore, the electrical connection component can be suitably used for vehicles such as automobiles.

It is a partial cross section figure of the electrical connection components comprised as a terminal pair in an Example. FIG. 2 is an enlarged view in the vicinity of a first contact portion in FIG. 1. It is sectional drawing of the test piece used for the contact resistance measurement in an experiment example. It is explanatory drawing which shows the structure of the contact resistance measuring apparatus in an experiment example. It is a graph which shows the result of the contact resistance measurement using the test piece whose curvature radius r is 0.5 mm in an experiment example. It is a graph which shows the result of the contact resistance measurement using the test piece whose curvature radius r is 2 mm in an experiment example.

  In the electrical connection component, the first component may have one first contact portion, or may have two or more first contact portions. When the first component has two or more first contact portions, two or more electrical connections between the first component and the second component can be formed, and the area of the conductive portion can be increased. Therefore, the contact resistance of the electrical connection component can be reduced more easily.

  Further, in this case, even if the one first contact portion is separated from the second contact portion for some reason, the electrical connection with the second contact portion can be maintained in the other first contact portion. it can. Therefore, connection reliability can be further increased.

  The said 1st contact part may be comprised only from the 1st CuSn alloy layer, and may have a multilayer structure containing metal layers other than a 1st CuSn alloy layer. For example, an Sn layer may be provided on the first CuSn alloy layer. In this case, while the Sn layer is present between the first contact portion and the second contact portion, the relatively soft Sn layer is deformed, thereby easily increasing the contact area with the second contact portion. can do. As a result, the connection reliability between the first component and the second component can be further improved.

  The first contact portion may have a diffusion barrier layer that suppresses diffusion of the metal element from the first base material between the first base material and the first CuSn alloy layer. The diffusion barrier layer is usually made of Ni (nickel).

The first contact portion can be manufactured by, for example, sequentially forming a Cu plating film and an Sn plating film on the first base material, and then heating these plating films to perform a reflow process. The first CuSn alloy layer preferably contains a Cu ₆ Sn ₅ intermetallic compound. The Cu ₆ Sn ₅ intermetallic compound has a relatively high conductivity among CuSn alloys. Therefore, in this case, the contact resistance of the electrical connection component can be further reduced.

  The first contact portion has a substantially hemispherical shape that bulges toward the second contact portion. The outer surface of the first contact portion may be an ideal true sphere, and may have a shape distorted from a true sphere such as a spheroid. The radius of curvature r of the first contact portion is a radius of a phantom sphere that approximates the shape of the first contact portion that directly contacts the second contact portion and the vicinity thereof.

  Similar to the first contact portion, the second contact portion may be composed of only the second CuSn alloy layer, or may have a multilayer structure including a metal layer other than the second CuSn alloy layer. Examples of the metal layer other than the second CuSn alloy layer include an Sn layer disposed on the second CuSn alloy layer and a diffusion barrier layer disposed between the second base material and the second CuSn alloy layer. The manufacturing method of the second contact portion is the same as that of the first contact portion.

In a state where the first contact portion and the second contact portion are in contact with each other, a curvature radius r [mm] of the first contact portion and a contact load F [between the first contact portion and the second contact portion are described. N] satisfies the above formula (1) and the above formula (2).
F ^1/3 r ^-2/3 ≧ 0.8 (1)
F ≦ 5 (2)

  The said electrical connection component can suppress the increase in contact resistance by satisfy | filling said Formula (1). This is considered to be due to the following reason.

  When vibration is applied during use of the electrical connection component, it is considered that a complex oxide of Cu and Su is formed at the contact portion between the first CuSn alloy layer and the second CuSn alloy layer as described above. In order to suppress an increase in contact resistance between the first contact portion and the second contact portion, it is necessary to remove this complex oxide from the contact portion.

Here, the electrical connection component includes the first contact portion having a substantially hemispherical shape and the second contact portion having a substantially flat plate shape. Therefore, the maximum stress P _max [Pa] at the contact portion when the first contact portion and the second contact portion are in contact can be estimated by the following formula (1 ′). Note that E and ν in the following equation are the Young's modulus [Pa] and Poisson's ratio of the material that contacts at the contact portion.

In the state where the first CuSn alloy layer and the second CuSn alloy layer are in contact with each other, the values of E and ν in the above formula (1 ′) are the Young's modulus and Poisson's ratio of the CuSn alloy. Therefore, the maximum stress P _max at the contact portion can be estimated only from the value of the curvature radius r [mm] and the value of the contact load F [N]. That is, the maximum stress P _max can be increased as the value of F ^1/3 r ^−2/3 is increased.

And when the maximum stress P _max is sufficiently high, when the first contact part and the second contact part slide due to vibration during use, the complex oxide of Cu and Sn can be destroyed, Furthermore, it is considered that the complex oxide can be discharged from the contact portion between the first contact portion and the second contact portion. As a result, when the above formula (1) is satisfied, the CuSn alloy layers are in direct contact with each other without an insulator, and as a result, increase in contact resistance can be suppressed.

In order to increase the value of F ^1/3 r ^−2/3, the value of the contact load F may be increased, and the value of the curvature radius r may be decreased. However, when the contact load exceeds 5N, it is difficult to reduce the size of the electrical connection component. Therefore, the electrical connection component can easily be reduced in size while suppressing an increase in contact resistance by satisfying both of the formula (1) and the formula (2).

It is preferable that the curvature radius r and the contact load F satisfy the following formula (3).
F ^1/3 r ^-2/3 ≧ 1 (3)

In this case, the maximum stress P _max applied to the contact portion between the first CuSn alloy layer and the second CuSn alloy layer can be further increased. As a result, an increase in contact resistance can be more easily suppressed.

  Moreover, it is preferable that the said 1st contact part has the said curvature radius r of 1 mm or less. In this case, the electrical connection component can be more easily downsized.

  The first CuSn alloy layer and the second CuSn alloy layer preferably have a thickness of 2 μm or more. In this case, the time until the first CuSn alloy layer and the second CuSn alloy layer are worn out becomes longer. Therefore, the electrical connection component can maintain a low contact resistance for a longer period.

  As described above, the electrical connection component can maintain a low contact resistance over a long period of time and can be easily downsized. Therefore, the electrical connection component can be suitably used for vehicles such as automobiles that are particularly demanding for downsizing.

  The electrical connection component can be configured in various forms. For example, the electrical connection component may be configured as a terminal pair. In this case, either the first component or the second component can be configured as a male terminal, and the other as a female terminal fitted into the male terminal.

  Moreover, you may comprise the said electrical connection component as a connector pair which has a male connector and a female connector. In this case, either the first component or the second component can be configured as a male connector, and the other as a female connector that fits into the male connector.

  The male connector and the female connector may have a conventionally known shape. The male connector can be configured to include one or a plurality of first contact portions and a housing that holds the first contact portions. The female connector can be configured to include one or a plurality of second contact portions and a housing that holds the second contact portions. The 1st contact part and the 2nd contact part may be connected with wiring tools, such as an electric wire, respectively.

(Example)
An example of the electrical connection component will be described with reference to the drawings. As shown in FIG. 1, the electrical connection component 1 of this example is a terminal pair 10 including a male terminal 20 and a female terminal 30 fitted to the male terminal 20. In this example, the first component 3 is a female terminal 30 and the second component 2 is a male terminal 20.

  The female terminal 30 which is the first component 3 has a first contact portion 33 having a first base material 31 made of metal and a first CuSn alloy layer 32 present on the first base material 31. The first contact portion 33 has a substantially hemispherical shape that bulges toward the second contact portion 23 side.

  The male terminal 20 which is the second component 2 has a second contact portion 23 having a second base material 21 made of metal and a second CuSn alloy layer 22 existing on the second base material 21. The second contact portion 23 has a flat plate shape.

As shown in FIGS. 1 and 2, the terminal pair 10 of this example is configured such that the first CuSn alloy layer 32 and the second CuSn alloy layer 22 come into contact with each other. And the 1st contact part 33 and the 2nd contact part 23 in the state which the curvature radius r [mm] of the 1st contact part 33 shown in FIG. 2, and the 1st CuSn alloy layer 32 and the 2nd CuSn alloy layer 22 contact | abutted. And the contact load F [N] to satisfy the following formula (1) and the following formula (2).
F ^1/3 r ^-2/3 ≧ 0.8 (1)
F ≦ 5 (2)

  Hereinafter, the configuration of the terminal pair 10 of this example will be described in detail with reference to FIG. The male terminal 20 has a barrel part (not shown) for crimping the electric wire, a cylindrical body part (not shown) connected to the barrel part, and a tab part 24 connected to the cylindrical body part. The male terminal 20 has a substantially rod shape, and a barrel portion, a cylindrical body portion, and a tab portion 24 are arranged in a line. The tab portion 24 extends in the longitudinal direction of the male terminal 20 with one open end of the cylindrical body portion as a base end, and has a flat cross section perpendicular to the extending direction. The second contact portion 23 is disposed on the flat portion 241 in the tab portion 24.

  The male terminal 20 can be produced, for example, by the following method. First, a plate-like second base material 21 made of a Cu alloy is prepared, and pretreatment such as degreasing and cleaning is performed. Next, an Sn plating film having a thickness of 1 to 3 μm is formed on the entire surface of the second base material 21 by electroplating. After the plating film is formed, the second CuSn alloy layer 22 is formed by diffusing Cu of the second base material 21 by performing reflow treatment by heating under a conventionally known condition. In addition, you may form other plating films, such as Ni plating film and Cu plating film, between the 2nd preform | base_material 21 and Sn plating film as needed. In addition, it is possible to form the Sn layer on the second CuSn alloy layer 22 by increasing the thickness of the Sn plating film.

  Thereafter, the second base material 21 on which the second CuSn alloy layer 22 is formed is subjected to press working to form the shape of the male terminal 20. Thus, the male terminal 20 can be obtained.

  The female terminal 30 has a substantially rod shape, and has a barrel portion (not shown) for crimping an electric wire and a cylindrical body portion 34 connected to the barrel portion. The cylindrical body portion 34 has a substantially square cylindrical shape extending in the longitudinal direction of the female terminal 30. One open end 341 of the cylindrical body portion 34 is open so that the tab portion 24 can be inserted.

  An elastic piece portion 35 is provided inside the cylindrical body portion 34. The elastic piece portion 35 is formed by folding the bottom plate portion 342 of the cylindrical body portion 34 inwardly and rearwardly, and the tab portion 24 inserted into the cylindrical body portion 34 faces the bottom plate portion 342. It can be pressed toward the plate portion 343 side.

  A first contact portion 33 that protrudes toward the top plate portion 343 so as to have a hemispherical shape is formed at a substantially central portion of the elastic piece portion 35 in the longitudinal direction. The first contact portion 33 is pressed against the tab portion 24 by the pressing force of the elastic piece portion 35 in a state where the tab portion 24 of the male terminal 20 is inserted into the cylindrical body portion 34. Thereby, the 1st CuSn alloy layer 32 and the 2nd CuSn alloy layer 22 contact, and the male terminal 20 and the female terminal 30 can be conducted.

  The female terminal 30 can be produced by the same method as the male terminal 20. That is, after pre-processing the plate-shaped first base material 31 made of a Cu alloy, an Sn plating film or the like is formed by electroplating. Subsequently, the 1st base material 31 is heated on conventionally well-known conditions, and the reflow process is performed, and the 1st CuSn alloy layer 32 is formed. Thereafter, the first base material 31 on which the first CuSn alloy layer 32 is formed is pressed to form the female terminal 30 in shape. Thus, the female terminal 30 can be obtained.

  The terminal pair 10 having the above configuration includes a first contact portion 33 having a substantially hemispherical shape and a second contact portion 23 having a substantially flat plate shape, and the above formula (1) and the above formula (2) are obtained. It is configured to meet. Therefore, a sufficiently large stress can be applied to the contact portion between the first contact portion 33 and the second contact portion 23 without increasing the contact load F. As a result, a low contact resistance can be easily maintained over a long period of time even in a use environment where vibration or the like is applied.

  Further, the terminal pair 10 does not need to increase the contact load F in order to suppress an increase in contact resistance. Therefore, the plate thickness of the first base material 31 and the second base material 21 can be reduced. As a result, the terminal pair 10 can be easily downsized.

(Experimental example)
In this example, the value of the contact resistance when the radius of curvature r of the first contact portion 33 and the contact load F between the first contact portion 33 and the second contact portion 23 are variously changed is measured. Hereinafter, a method for producing a test piece and a test method will be described.

<Method for preparing specimen>
A Cu alloy plate was prepared and subjected to pretreatment such as degreasing and cleaning. Next, an Sn plating film having a thickness of 1 μm was formed on one surface of the Cu alloy plate by electroplating. After forming the plating film, a CuSn alloy layer was formed on the Cu alloy plate by performing reflow treatment by heating at 350 ° C. for 20 seconds. The Cu alloy plate was cut to produce a second part 2 (see FIG. 3) having a flat plate shape.

  In addition to the production of the second component 2, the Cu alloy plate was cut into a rectangular shape. The first contact portion 33 was formed by pressing the rectangular metal piece so that the CuSn alloy layer side protruded in a hemispherical shape. Thus, the first component 3 (see FIG. 3) was produced. 3 that are the same as those used in FIG. 1 to FIG. 2 indicate the same components as those in the embodiment unless otherwise specified.

  In this example, test pieces were produced in which the curvature radius of the first contact portion 33 was variously changed as shown in Table 1.

<Measurement method of contact resistance>
As shown in FIG. 4, the contact resistance measuring device 4 used in this example includes a load cell 41, an actuator 42 facing the load cell 41, a DC power supply 43, and a voltmeter 44. The DC power supply 43 and the voltmeter 44 are connected to the first component 3 and the second component 2, respectively, and constitute an electric circuit for measuring contact resistance.

  The arrangement of the first component 3 and the second component 2 on the contact resistance measuring device 4 is performed as follows. First, the first component 3 is fixed to the load cell 41, and each of the DC power supply 43 and the voltmeter 44 is electrically connected to the first component 3. Next, the second component 2 is fixed to the actuator 42, and each of the DC power supply 43 and the voltmeter 44 is electrically connected to the second component 2.

  After arranging the first component 3 and the second component 2 as described above, the actuator 42 was operated to bring the second component 2 into contact with the first component 3. Next, while measuring the contact load F between the first component 3 and the second component 2 by the load cell 41, the second component 2 was brought close to the first component 3, and the contact load F was set to the value shown in Table 1. While maintaining this contact load, the second component 2 was reciprocated in the horizontal direction (FIG. 4, arrow 400), and the first contact portion 33 and the second contact portion 23 were slid. In this example, the amplitude of the second component 2 was 60 μm, and the period of reciprocation was 1 second. The number of reciprocations of the second component 2 was either 100 times or 50 times.

  While the first contact portion 33 and the second contact portion 23 are slid, a current having a constant magnitude is generated from the DC power supply 43, and the current including the DC power supply 43, the first component 3 and the second component 2 is generated. Current was passed through path i. At this time, the potential difference generated between the first part 3 and the second part 2 was measured by the voltmeter 44. Then, the contact resistance between the first component 3 and the second component 2 was calculated by dividing the obtained potential difference by the magnitude of the current.

Table 1 shows the results of the above measurement performed by changing the curvature radius r and the contact load F in various ways. In addition, the meaning of the symbol shown in the column of “Evaluation Result” in Table 1 is as follows.
A: The maximum value of contact resistance during measurement is within 1.5 times the contact resistance at the start of measurement B: The maximum value of contact resistance during measurement is within twice the contact resistance at the start of measurement C: During measurement The maximum contact resistance is more than twice the contact resistance at the start of measurement.

  5 and 6 show an example of the transition of the contact resistance value in the measurement where the evaluation result is “A” and the transition of the contact resistance value in the measurement where the evaluation result is “C”. Note that the vertical axis in FIGS. 5 and 6 is the value of contact resistance (mΩ) and is logarithmically displayed. The horizontal axis represents the number of reciprocations of the second component 2.

From Table 1 and Fig. 4, when the value of F ^1/3 r ^-2/3 is 0.8 or more, the maximum value of the contact resistance during measurement is within 1.5 times the contact resistance at the start of measurement. Thus, it can be understood that a low contact resistance can be maintained over a long period of time.

DESCRIPTION OF SYMBOLS 1 Electrical connection part 2 2nd part 21 2nd preform | base_material 22 2nd CuSn alloy 23 2nd contact part 3 1st part 31 1st preform | base_material 32 1st CuSn alloy 33 1st contact part

Claims (7)

An electrical connection part used by contacting a first contact part provided in the first part and a second contact part provided in the second part,
The first contact portion has a first base material made of metal and a first CuSn alloy layer existing on the first base material, and has a substantially hemispherical shape bulging toward the second contact portion side. And
The second contact portion has a second base material made of metal and a second CuSn alloy layer present on the second base material, and has a substantially flat plate shape,
The contact load F [of the first contact portion and the second contact portion in a state where the curvature radius r [mm] of the first contact portion is in contact with the first CuSn alloy layer and the second CuSn alloy layer. N] satisfies the following formula (1) and the following formula (2).
F ^1/3 r ^-2/3 ≧ 0.8 (1)
F ≦ 5 (2) The electrical connection component according to claim 1, wherein the curvature radius r and the contact load F further satisfy the following formula (3).
F ^1/3 r ^-2/3 ≧ 1 (3)   The electrical connection component according to claim 1, wherein the first contact portion has the radius of curvature of 1 mm or less.   The electrical connection component according to claim 1, wherein the first CuSn alloy layer and the second CuSn alloy layer have a thickness of 2 μm or more.   The electrical connection component according to claim 1, wherein the electrical connection component is for a vehicle. A terminal pair comprising the electrical connection component according to claim 1,
The terminal pair includes a male terminal composed of either the first component or the second component;
A terminal pair comprising: a female terminal that is formed of the other of the first part or the second part and fits into the male terminal. A connector pair comprising the electrical connection component according to any one of claims 1 to 5,
The connector pair includes a male connector composed of either the first component or the second component;
A connector pair comprising: a female connector that is formed of the other of the first part and the second part and fits into the male connector.

Images