JP2010205616A - Crimp terminal, and crimping structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crimping terminal for an aluminum wire or the like, which can expedite adhesion by crimping and can improve electric connection performance when using the aluminum wire or the like. <P>SOLUTION: The crimp terminal 10 includes portions formed by applying tin plating to the surface of a conductive base material, and a conductor crimping part 13 among those portions is crimped to the conductor part 100a of a wire 100 to electrically connect the terminal to the wire. Surface roughness of the conductor crimping part prior to crimping is 0.1-1.0 μm, and the conductor crimping part adheres to the conductor part by crimping, in the crimp terminal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crimp terminal and a crimp structure for an aluminum electric wire.

  As a method for connecting the terminal and the electric wire, a method called crimping is widely used. For crimping, insert the conductor exposed part of the wire into the U-shaped crimping part provided on the terminal, and connect the wire to the crimping part by crimping the crimping part with a crimping jig etc. so as to wrap the conductor exposed part To do.

Conventionally, in order to improve the connection performance by crimping, tin plating is applied to the surface of the terminal, thereby improving the crimping performance. When such a tin-plated terminal is crimped to an electric wire, it is known that the plated tin can improve the connection performance by mediating the conductor of the electric wire and the terminal base material. Patent Document 1 states that “a method of manufacturing a fitting-type connection terminal that obtains electrical contact by fitting a male part and a female part, and (a) at least one of the male part and the female part. A plating step of forming a tin plating layer on the surface of the copper base material; and (b) the vicinity of the interface with the copper base material of the tin plating layer by performing a heat treatment on the copper base material on which the tin plating layer is formed. It is known to reduce the terminal insertion force by “a method of manufacturing a fitting-type connection terminal, comprising a heat treatment step of alloying only Cu ₆ Sn ₅ with a heat treatment step”.

  By the way, it is common to use a copper electric wire for a wire harness routed inside a vehicle such as an automobile, and it is difficult to use an aluminum electric wire having poor properties (physical properties) such as conductivity and strength. For that reason, it has not been used much in the past. However, in recent years, there has been a growing demand for the use of aluminum wires in view of lighter vehicles, lower fuel consumption, and recyclability.

  In the case of using an aluminum electric wire, it is necessary to further improve the connection performance of the crimping part because aluminum or aluminum alloy constituting the conductor is inferior in mechanical strength and electrical conductivity to copper. In addition, since an oxide film having a high specific resistance value is usually formed on the surface of a conductor made of aluminum or aluminum alloy, the conductors (terminal and aluminum or aluminum are broken while tearing the oxide film during crimping. Sufficient contact conduction between the alloy conductor and the conductor must be achieved. However, in the past, since the use of aluminum wires is small, these points have not been sufficiently studied.

JP-A-10-302867

  Even when an aluminum electric wire is crimped to a terminal, the use of the tin-plated terminal described above contributes to an improvement in connection performance, but the conventional one has not yet been expected to have a sufficient performance improvement.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to promote adhesion by crimping when using an aluminum electric wire or the like, and to expect an improvement in electrical connection performance. To provide a crimping terminal and a crimping structure for the like.

In order to achieve the above object, the present invention is characterized by the following.
1) A crimping terminal that has a tin-plated portion on the surface of a conductive base material, and a conductor crimping portion of the portion is crimped to a conductor portion of an electric wire to be electrically connected to the electric wire. The crimp terminal according to claim 1, wherein the conductor crimping portion has a surface roughness of 0.1 to 1.0 μm, and the conductor crimping portion and the conductor portion are adhered by the crimping.
2) The crimp terminal according to 1) above, wherein the electric wire is an aluminum electric wire having a conductor portion made of aluminum or aluminum alloy as the conductor portion.
3) The crimp terminal according to 1) or 2) above, wherein dimple-like irregularities are formed on the surface of the conductor crimping portion.
4) The crimp terminal according to 3) above, wherein the surface of the conductor crimping portion is processed by shot peening.
5) An aluminum electric wire having a conductor portion made of aluminum or aluminum alloy, and a crimp terminal having a portion plated with tin on the surface of the conductive base material, wherein the conductor crimp portion is the portion of the crimp terminal. Crimped to the conductor portion of the aluminum wire, whereby the crimp terminal is electrically connected to the aluminum wire,
A crimping structure, wherein a surface roughness of a conductor portion of the aluminum electric wire before crimping is 0.1 to 1.0 μm, and the conductor crimping portion and the conductor portion are adhered by the crimping.
6) The crimp structure according to 5) above, wherein dimple-like irregularities are formed on the surface of the conductor portion of the aluminum electric wire to which the conductor crimp portion is crimped.
7) The crimp structure according to 6) above, wherein the surface of the conductor portion of the aluminum electric wire to be crimped by the conductor crimp portion is processed by shot peening.

  According to the present invention, since the surface roughness of the terminal-plated portion and / or the conductor portion of the aluminum electric wire is specified, the contact area of the connection portion is increased and the adhesion between the terminal and the conductor is promoted. It is possible to improve the reliability of electrical connection between the terminal and the electric wire.

It is a figure for demonstrating the adhesion method in the crimp terminal of an aluminum electric wire and a terminal. It is sectional drawing of the crimping | compression-bonding part in the crimp terminal of FIG. It is a longitudinal cross-sectional view of the serrated portion of the conductor crimping portion. It is a sectional side view which shows the relationship between the said conductor crimping | compression-bonding part and the conductor of an electric wire. It is sectional drawing which shows typically the state which the tin plated by the crimping | compression-bonding part has entered into the clearance gap between the strands which comprise a conductor part. It is explanatory drawing of the plating method. It is explanatory drawing of the method of another plating. It is explanatory drawing of another plating method. It is a figure which shows the result of the example which modeled the crimping | compression-bonding part and tested the electrical connection performance of the crimping | compression-bonding part.

In the present invention, the conductor portion of the electric wire connected to the conductor crimping portion in the portion where the surface of the conductive base material on the terminal side is tin-plated is collectively referred to as a crimping portion. In the present invention, the surface roughness of the crimping part may be specified only on the terminal side, only on the conductor part side, or both. In the crimping portion, the region where the conductor portion and the tin-plated portion are actually connected by crimping is at least part of the conductor crimping portion and the conductor portion. In addition, a conductor part is a partial specific area | region of the electric wire conductor connected with the conductor crimping | compression-bonding part by the side of a terminal. Furthermore, in this invention, the conductor of an aluminum electric wire is the meaning containing aluminum simple substance and aluminum alloy. In Claim 1, although the raw material of the conductor part of an electric wire is not specifically limited, such as copper and aluminum, aluminum or aluminum alloy is suitable.
In the present invention, the surface roughness of the conductor crimping part or conductor part before connection is 0.1 to 1.0 μm, preferably 0.2 to 0.8 μm, more preferably 0.3 to 0.6 μm. If the surface roughness is less than 0.1 μm and more than 1.0 μm, sufficient adhesion cannot be obtained. In the present invention, in the crimp terminal and the crimp structure, the conductor crimping portion and the surface roughness of the conductor portion may be defined as described above. Moreover, the area | region where surface roughness is prescribed | regulated by the scope of the present invention may include other areas as long as at least the above-mentioned crimping part is included.
In this invention, the surface roughness in a crimping | compression-bonding part is defined as the arithmetic mean roughness prescribed | regulated by JISB0601-1994.
The surface for obtaining the surface roughness is not particularly limited but is preferably composed of dimple-like irregularities.
The means for obtaining the surface roughness is not particularly limited, and includes shot peening, embossing with a roller or the like, and shot peening is preferable.
The material used for shot peening is not particularly limited, but those using ceramic fine particles are preferable. As this material, a spherical shape or a shape similar to a spherical shape is preferable from the viewpoint that the surface can be formed in a dimple shape, and the average particle size is preferably 20 to 100 μm, and more preferably 40 to 60 μm.
The crimped part that has been surface-treated so that the surface roughness is within the range of the present invention has a moderately rough surface, increases the contact area of the crimped part, and increases the sliding resistance in the terminal connection process as described later. Therefore, the adhesion (interatomic bond) energy is increased, and the reliability of the crimp terminal is improved.
In particular, the pressure-bonded parts that have been surface-treated by shot peening have increased surface hardness and at the same time improved hardness, which can be expected to further increase sliding resistance in the terminal connection process. The reliability of the crimp terminal and the crimp structure can be expected to increase.

The terminal connecting step is a step of connecting the crimping part by adhesion so as to be electrically conducted. In the present invention, adhesion means that at least an interatomic bond between a tin atom on the terminal side and an atom in the conductor portion is formed in the crimping portion. This interatomic bond may be formed between the conductive base material constituting atom of the terminal and the atom of the conductor portion. Hereinafter, the conductive base material is also simply referred to as a base material.
This adhesion is performed by applying pressure to at least the crimping part. If necessary, heat may be further applied.

  Next, the adhesion mechanism will be described based on an example in which the crimping part is modeled and the electrical connection performance of the crimping part is tested.

FIG. 9 shows that a sample plate (corresponding to a conductor crimping portion of a terminal) having a convex contact portion tin-plated with a copper alloy is pressed against a copper plate (corresponding to a conductor portion of a copper wire) through this contact portion. In the same manner, a sample plate (corresponding to a conductor crimping part of a terminal) having a convex contact part plated with tin on the copper alloy is similarly applied to an aluminum plate (corresponding to a conductor part of an aluminum electric wire). The results of examining changes in pressure load (corresponding to the strength of the terminal crimping portion) and electrical resistance (corresponding to the contact resistance of the crimping portion) in each of the cases shown in FIG.
The unit of load is N, and the unit of resistance is Ω. The white point group plots the resistance change when the load between the copper plate and the sample plate or between the aluminum plate and the sample plate is gradually increased (in the figure, between the copper plate and the sample plate). , Cu indicates an arrow pointing to the right, and between aluminum plate and sample plate, Al indicates an arrow pointing to the right), and a black point group is between a copper plate and a sample plate or an aluminum plate and a sample. After applying the load between the plates to the maximum value (10N), after sliding the sample plate by 1 mm, plot the resistance change when the load is gradually decreased (in the figure, between the copper plate and the sample plate) , Cu indicates an arrow pointing left, and between the aluminum plate and the sample plate, Al indicates an arrow indicating left).
As the sample plate, a copper alloy provided with an indent was plated with tin (Sn), pure copper (C1020) was used as the copper plate, and aluminum (A1050) was used as the aluminum plate. The electrical resistance was measured with a digital multimeter, and the pressure load was measured with a force link.
The surface roughness of the plating surface of the sample plate is 0.046 μm, and the surface roughness of the aluminum plate is 0.048 μm.

Here, as shown in FIG. 9, when the plate is copper, the change in resistance is not so different when the load between the copper plate and the sample plate is increased or decreased.
On the other hand, when the plate is aluminum, it can be seen that the resistance change tends to greatly differ between when the load between the aluminum plate and the sample plate increases and when the load decreases. In particular, it can be seen that the resistance does not increase even when the load between the aluminum plate and the sample plate decreases. This is considered to be due to the fact that the affinity of the sample plate with respect to tin differs depending on whether the plate is copper or aluminum. Whether the plate is copper or aluminum, the plate surface and the tin surface of the sample plate are actually covered with an oxide film. In the case of aluminum, it is considered that the oxide film is broken by the load, the active surfaces of aluminum atoms and tin atoms are exposed, and the interatomic bond (adhesion) between aluminum and tin proceeds. As a result, the load is reduced at this stage. Even so, it is considered that the resistance between the aluminum plate and the sample plate hardly changes. In the case of copper, adhesion to tin is less likely to occur than aluminum, so the above result is considered. Therefore, when crimping the conductor crimping portion of the terminal to the conductor portion of the aluminum conductor, it is important to promote the sliding of the crimping portion and expose the active surface under a certain load. I understand that.
The present invention applies this principle.
In the electrical connection performance test, the test was performed under the same conditions as above except that the combination of the tin-plated sample plate and the aluminum plate was changed to the following combinations (Examples 1 to 7).
(1)
Tin-plated sample plate: The surface roughness was 0.05 μm (Example 1), 0.4 μm (Example 2), and 1.2 μm (Example 3).
Aluminum plate: Same as in FIG.
(2)
Tin-plated sample plate: same as in FIG.
Aluminum plate: The surface roughness was 0.05 μm (Example 4), 1.2 μm (Example 5), and 2.2 μm (Example 6).
(3)
Tin-plated sample plate: The surface roughness was 0.05 μm (Example 7), 0.4 μm (Example 8), and 1.2 μm (Example 9).
Copper plate: Same as in FIG.
As a result of the above test, the shape of the change in contact resistance with respect to the load between the aluminum plate and the sample plate and between the copper plate and the sample plate was almost the same as in FIG. The results of comparing the contact resistance when the load is reduced to 0.1 N are as follows.
In Example 2, the contact resistance was lower than those in Examples 1, 3 and 9. In Example 5, the contact resistance was lower than the results of Examples 4, 6 and 9. In Example 8, the contact resistance was lower than those in Examples 7, 9 and FIG.

The present invention has been briefly described above. Furthermore, specific embodiments for carrying out the invention described below will be described with reference to the accompanying drawings, but the present invention is not limited to these examples.
1 is a diagram for explaining a method of adhering an aluminum electric wire and a terminal in a crimp terminal, FIG. 2 is a sectional view of a crimp part in the crimp terminal of FIG. 1, and FIG. 3 is a longitudinal section of a serrated portion of a conductor crimp part. FIG. 4 is a side sectional view showing the relationship between the conductor crimping portion and the conductor of the electric wire, and FIG. 5 is a schematic view of the state where tin plated on the conductor crimping portion enters the gap between the strands constituting the conductor portion. It is sectional drawing shown.

  In FIG. 1, 10 is a terminal, 100 is an aluminum electric wire (aluminum conductor), and 31 and 32 are a lower die and an upper die of a crimping jig. In this embodiment, the terminal 10 in which tin plating 52 is applied to the surface of a terminal base material 51 (FIG. 5) made of copper or copper alloy is used. Moreover, the aluminum electric wire 100 has the conductor part 100a made from aluminum which consists of a bundle | flux of the some strand 100c (FIG. 5) of forms, such as a strand wire, in the center of the insulation coating 100b.

  The terminal 10 includes an electrical connection portion 12 for a counterpart terminal on the front end side in the longitudinal direction (hereinafter, this direction is referred to as “front-rear direction” and the direction orthogonal thereto is referred to as “left-right direction”). Are provided with a conductor crimping portion 13 for crimping the conductor portion 100a with the exposed end of the aluminum wire 100 and a covering crimping portion 14 for crimping a portion of the aluminum wire 100 having the coating 100b. The conductor crimping portion 13 and the covering crimping portion 14 are configured to include a common bottom plate portion 11.

  The conductor crimping portion 13 is a U-shaped section in which a pair of conductor crimping pieces 13a are erected on both lateral edges of the bottom plate portion 11 continuous from the electrical connecting portion 12, and the terminal 10 A plurality of serrations (that is, shallow grooves lined by pressing) 13b extending in the left-right direction are provided. Further, the covering crimping portion 14 is a U-shaped section in which a pair of covering crimping pieces 14 a are formed upright on both lateral edges of the bottom plate portion 11, and the conductor crimping portion 13 and the coating crimping portion 14 are Are arranged at an appropriate interval in the front-rear direction.

  The tin plating 52 is thinly applied to the electrical connection portion 12 on the front end side of the terminal 10, but is thickly applied to the conductor crimping portion 13 and the covering crimping portion 14 on the rear end side of the terminal 10. In FIG. 1, the portion where the thickness of the plating is thick is indicated by hatching. In particular, the surface roughness of the inner surface of the conductor crimping portion 13 which is a portion that contacts the aluminum conductor portion 100a of the aluminum electric wire 100 when the conductor crimping piece 13a is crimped is 0.1 to 1.0 μm. Is set. The thickness of the tin plating 52 is 1.0 μm.

  When the terminal 10 having this configuration is crimped to the conductor portion 100a where the tip of the aluminum wire 100 is exposed, first, the terminal 10 is placed on the placement surface 31a of the lower mold 31 and the conductor portion 100a at the tip of the aluminum wire 100 is placed. Is inserted between the conductor crimping pieces 13 a of the conductor crimping part 13 and placed on the bottom plate part 11. Then, by lowering the upper die 32, the leading end side of the conductor crimping piece 13a is gradually brought inward by the guide slope 32a of the upper die 32, and finally, the guide slope 32a is moved to the central mountain portion 32b. The conductor crimping piece 13a is rounded so as to be folded back toward the conductor part 100a with the continuous curved surface, and the conductor part 100a is bitten into the conductor part 100a as shown in FIG. The conductor crimping piece 13a is crimped so as to wrap the wire. About the covering crimping part 14, before crimping the conductor crimping part 13, the part which has the coating 100b of the conductor 100 similarly to the above is crimped beforehand.

  Thus, when the conductor crimping part 13 is crimped to the conductor part 100a by crimping the conductor crimping piece 13a, the conductive metal constituting the terminal 10 and the aluminum of the conductor part 100a can be adhered to each other. 10 and the aluminum electric wire 100 can be strongly coupled electrically and mechanically.

  That is, since the surface roughness of the inner surface of the conductor crimping portion 13 of the terminal 10 is set in the range of 0.1 to 1.0 μm, the tin plated on the terminal base material 51 as shown in FIGS. And the conductor part 100a can be enhanced, and electrical connection can be stabilized. In particular, as shown in FIG. 5, tin of the tin plating 52 on the terminal base material 51 fills the gaps between the strands 100 c while adhering to the surface of the strand 100 c constituting the conductor by pressure bonding. Therefore, the contact area between the strands 100c and between the strand 100c and the terminal can be increased, the adhesion region can be increased, the contact resistance can be reduced, and the contact reliability is improved.

  As shown in FIG. 3, when the conductor crimping portion 13 has serrations 13b on the inner surface, the tin plating 52 (see FIG. 5) deformed by crimping enters the serrations 13b and the aluminum conductor portion 100a. As a result, the bonding strength of the terminal 10 with respect to the axial direction of the aluminum electric wire 100 is increased.

  Next, a method for plating thickly only the rear end side of the terminal 10 (the portion where the conductor crimping portion 13 is present) will be briefly described.

  FIG. 6 is an explanatory diagram of the first method. In this method, the front end side of the terminal 10 in a continuous state (the portion where the electrical contact portion 12 is provided) is put on the plating solution 252 in the plating tank 250 and the rear end side of the terminal 10 ( Plating is performed while the terminal 10 is moved horizontally by immersing the conductor crimping portion 13 and the conductor crimping piece 14 in the plating solution 252. By selectively plating in this way, only the rear end side of the terminal 10 including the conductor crimping portion 13 can be plated thick.

  FIG. 7 is an explanatory diagram of the second method. In this method, the terminal 10 in a state of being connected to the carry 200 after the press work is directed to the front end side (the portion where the electrical contact portion 12 is located) and the rear end side (the conductor crimping portion 13 or the conductor crimping piece). 14 is passed through the plating solution 252 while moving obliquely from the bottom to the top. When moving obliquely in this manner, the time of bathing in the plating solution 252 becomes longer on the rear end side than on the front end side of the terminal 10. Accordingly, the plating thickness in the portion where the bathing time is long in the plating solution 252 is increased, the plating thickness in the portion where the bathing time is short in the plating solution 252 is reduced, and the terminal 10 including the conductor crimping portion 13 is rearranged. Only the end side can be plated thick.

FIG. 8 is an explanatory diagram of the third method. In this method, at the stage of the material 300 before the terminal is pressed, the portion 312 that becomes the electrical contact portion on the front end side is distinguished from the portion 315 that becomes the conductor crimping portion and the covering crimping portion on the rear end side. Masking 350 is applied to this area, and only the latter area is selectively plated. Then, by pressing the electrical connection portion, the conductor crimping portion, and the covering crimping portion after plating, it is possible to obtain a terminal plated only on the rear end side.
When plating is performed by applying the masking 350 as described above, only one surface of the material 300 can be plated, and therefore only the inner surface of the conductor crimping portion of the terminal can be plated.
Although the surface treatment of the conductor crimping portion of the terminal can be performed by the first and second methods, it is preferable to treat the plated surface obtained by the third method so that the surface roughness is within the scope of the present invention. .

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

For example, the conductor 100a of the aluminum electric wire 100 may be made of an aluminum alloy. Specific examples of the aluminum alloy include an alloy of aluminum and iron. When this alloy is employed, it is easier to extend and the strength (particularly the tensile strength) can be increased compared to an aluminum conductor.
Moreover, in the said embodiment, although the surface roughness of only the conductor crimping part of a terminal was prescribed | regulated, you may use together what prescribed | regulated the surface roughness of the conductor part of an aluminum electric wire. Or you may use what prescribed | regulated the surface roughness of this conductor part instead of prescribing | regulating the surface roughness of a terminal.

10: terminal 11: bottom plate part 12: electrical connection part 13: conductor crimping part 13a: conductor crimping piece 51: terminal base material 52: tin plating 100: aluminum electric wire 100a: conductor part made of aluminum

Claims (7)

  It has a portion plated with tin on the surface of the conductive base material, and a conductor crimping portion of the portion is a crimping terminal that is electrically connected to the wire by being crimped to the conductor portion of the wire, A crimp terminal, wherein the conductor crimping portion has a surface roughness of 0.1 to 1.0 μm, and the conductor crimping portion and the conductor portion adhere to each other by the crimping.   The crimp terminal according to claim 1, wherein the electric wire is an aluminum electric wire having a conductor portion made of aluminum or aluminum alloy as the conductor portion.   The crimp terminal according to claim 1, wherein dimple-like irregularities are formed on a surface of the conductor crimping portion.   The crimp terminal according to claim 3, wherein a surface of the conductor crimping portion is processed by shot peening. An aluminum electric wire having a conductor portion made of aluminum or an aluminum alloy, and a crimp terminal having a portion plated with tin on the surface of the conductive base material, and the conductor crimp portion of the portion of the crimp terminal is the aluminum electric wire A crimping structure in which the crimping terminal is electrically connected to the aluminum electric wire,
A crimping structure, wherein a surface roughness of a conductor portion of the aluminum electric wire before crimping is 0.1 to 1.0 μm, and the conductor crimping portion and the conductor portion are adhered by the crimping.   6. The crimping structure according to claim 5, wherein dimple-like irregularities are formed on the surface of the conductor portion of the aluminum electric wire to which the conductor crimping portion is crimped.   The crimping structure according to claim 6, wherein the surface of the conductor portion of the aluminum electric wire to which the conductor crimping portion is crimped is processed by shot peening.

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