JP2009252443A - Crimp terminal for aluminum wire and crimping structure using the crimp terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crimp terminal for an aluminum wire capable of stabilizing contact resistance of a crimping part under a heat cycle or thermal shock conditions, even with connection made with an aluminum wire by crimping of ordinary strength, not over-crimping. <P>SOLUTION: The crimp terminal is provided with a crimping part 12 getting in pressure contact with an aluminum-made or an aluminum alloy conductor Wa of an aluminum wire so as to wrap up the same from outside, and the crimping part 12 is structured at least of a laminated plate material P arranging a copper layer Pa made of copper or a copper alloy on an inner face side in contact with the conductor Wa, and an aluminum layer Pb made of aluminum or an aluminum alloy on an outer face side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Conventionally, the electric wire used for the wire harness for automobiles is generally a copper electric wire, but recently, there is a movement to replace it with an aluminum electric wire because of its light weight and good recyclability.

  This is because aluminum has a conductivity of about 60% as compared with copper, but the weight only needs to be 1/3, so that significant weight reduction can be expected. Further, the melting point of copper is 1083 ° C., whereas the melting point of aluminum is 660 ° C., so that there is an advantage that the metal can be easily recovered.

When the electric wire of the automobile wire harness is an aluminum electric wire, there are the following problems when a copper terminal is used as the crimp terminal. Aluminum has a larger coefficient of linear expansion than copper. The linear expansion coefficient of aluminum is 23.5 × 10 ⁻⁶ / ° C., and the linear expansion coefficient of copper is 17.0 × 10 ⁻⁶ / ° C., so aluminum expands according to the temperature change by about 1.4 times that of copper. Easy to shrink. Therefore, when the copper terminal is crimped to the aluminum electric wire, there arises a problem that the contact resistance between the aluminum conductor and the copper terminal becomes unstable under heat cycle or thermal shock conditions.

  This will be described in detail.

  4 is a cross-sectional view of a portion where a crimp terminal is crimped to a conductor of an aluminum electric wire, FIG. 4 (a) is a diagram showing a state when crimped at room temperature, and FIG. 4 (b) is a diagram when the ambient temperature is increased. FIG. 4C is a diagram showing a state in which a gap is formed at the interface between the terminal and the conductor as the ambient temperature is extremely lowered.

  The crimping portion 2 of the crimping terminal 1 has a substantially U-shape having a bottom plate 5 and a pair of crimping pieces 6 and 6 extending upward from both lateral edges of the bottom plate 5 before crimping. Yes. When crimping the crimp terminal 1, an aluminum (or aluminum alloy) conductor Wa of an aluminum electric wire is inserted on the bottom plate 5, and the crimping pieces 6 on both sides are bent inward by a crimping device, and the conductor Wa Clamp it so that it wraps around. Thereby, the crimp terminal 1 can be crimped and connected to the conductor Wa.

  By the way, when a copper terminal is used for the crimp terminal 1 and crimping is performed on the conductor of the aluminum electric wire at room temperature (23 ° C.), the cross section of the crimp part is as shown in FIG. In the cross section in this state, the reaction force acts on the interface between the conductor Wa and the crimp terminal 1 toward the center of the mutual thickness, and is balanced. However, this balance is due to the volume ratio at the temperature at which the crimp terminal 1 is crimped to the conductor Wa. When there is a temperature change, the contact state of the interface changes due to volume expansion. Specifically, the interface when crimped at room temperature 23 ° C. is affected by volume change in a temperature range −40 ° C. to 120 ° C. where the use of the wire harness is assumed.

  For example, as shown in FIG. 4B, when the ambient temperature rises higher than normal temperature, the inner aluminum conductor Wa has a larger volume expansion than the outer copper crimp terminal 1. The force shown by the arrow acts on the outer copper crimping terminal 1 from the inner aluminum conductor Wa, and no gap is generated at the interface between the crimping terminal 1 and the conductor Wa.

  On the other hand, as shown in FIG. 4C, when the ambient temperature falls to a lower temperature side than normal temperature, particularly when the ambient temperature falls to a very low temperature around −40 ° C., the outer copper crimp terminal 1 Since the inner aluminum conductor Wa has a larger volume shrinkage, the contact pressure at the interface between the outer copper crimp terminal 1 and the aluminum conductor Wa is lowered, and in the worst case, the crimp as shown in the figure. There is a possibility that a gap 7 is generated at the interface between the terminal 1 and the conductor Wa. When the gap 7 is generated, the contact resistance increases. Therefore, especially in low temperature conditions, the electrical connection performance is greatly reduced.

  Therefore, conventionally, in order to avoid such a problem, the crimp terminal is over-compressed by applying a larger load to the conductor of the electric wire, or an aluminum terminal made of the same material as the conductor of the electric wire is used as the crimp terminal. It is made to use (for example, refer patent document 1, 2).

As another technique, Patent Document 3 discloses that a composite metal material is produced by clad rolling an aluminum alloy material and a steel material in order to increase the strength of the terminal and to improve heat resistance and recyclability. The example of the terminal comprised so that aluminum alloy material may be connected to the conductor of an electric wire by material is shown.
JP 2003-249284 A JP 2003-317817 A JP 2004-200018 A

  However, when the crimping terminal is over-bonded to the conductor of the electric wire, the strength of the conductor may be reduced due to excessive crushing, so that the connecting portion due to the crimping is likely to be broken, and a problem with strength is likely to occur.

  In addition, as described in Patent Documents 1 and 2, when an aluminum terminal is used, since aluminum has a lower electrical conductivity than copper, the electrical resistance of the connection portion with the electric wire is increased, and adverse effects due to Joule heat are caused. There is a problem that it becomes easy to come out. In addition, since aluminum is inferior in spring property to copper, in the case of a terminal having a spring part, there is also a problem that the spring part is easy to sag.

  In addition, as in the technique described in Patent Document 3, when the terminal is constituted by a clad material of an aluminum alloy material and a steel material, and the aluminum alloy material is in contact with the conductor of the electric wire, the connecting portion with the electric wire is also used. There is a problem that the electrical resistance of the device becomes large.

  In view of the above circumstances, the present invention aims to stabilize the contact resistance of the crimped part under heat cycle and thermal shock conditions even when connected to an aluminum wire by normal-strength crimping rather than over-compression. The present invention provides a crimp terminal for an aluminum electric wire and a crimp structure using the crimp terminal that can exhibit a spring property close to that of a copper terminal and can reduce the electrical resistance of a connection portion with an electric wire. For the purpose.

  The crimp terminal for an aluminum electric wire of the invention of claim 1 has a crimp portion that is crimped so as to be wrapped from the outside with respect to the aluminum or aluminum alloy conductor of the aluminum wire, and at least the crimp portion is attached to the conductor. It is characterized by comprising a laminated plate material in which a copper layer made of copper or a copper alloy is arranged on the inner surface side to be contacted and an aluminum layer made of aluminum or an aluminum alloy is arranged on the outer surface side.

  The invention according to claim 2 is the press contact terminal for an aluminum electric wire according to claim 1, wherein the crimping portion extends from a bottom plate on which the conductor is placed on an upper surface, and both side edges in the width direction of the bottom plate, A pair of crimping pieces that are bent inward so as to enclose the conductor placed thereon and crimped to the conductor are configured in a substantially U shape.

  The invention of claim 3 is the crimp terminal for aluminum wires according to claim 1 or 2, wherein at least the thickness of the aluminum layer is set to be equal to or greater than the thickness of the copper layer.

  Invention of Claim 4 is the crimp terminal for aluminum electric wires of any one of Claims 1-3, Comprising: The whole terminal is comprised by the laminated board material of the said aluminum layer and a copper layer, It is characterized by the above-mentioned. It is said.

  The invention of claim 5 is the crimp terminal for an aluminum electric wire according to any one of claims 1 to 3, wherein only the crimp part is constituted by a laminated plate material of the aluminum layer and the copper layer. The portion is formed of a single-layer plate material composed of only a copper layer.

  Invention of Claim 6 is a crimping | compression-bonding structure using the crimp terminal for aluminum electric wires of any one of Claims 1-5, Comprising: The crimp part of the said crimp terminal for aluminum electric wires is made from aluminum of an aluminum electric wire. Alternatively, it is characterized by being crimped so as to be wrapped from the outside with respect to a conductor made of an aluminum alloy.

  According to the first aspect of the present invention, the crimping part that crimps the conductor of the electric wire is a bimetal structure in which an aluminum layer is laminated on the outer surface of the copper layer on the inner surface. The crimping part repeats contraction and expansion in a tendency closer to the conductor of the aluminum electric wire than the terminal (copper terminal) constituted only by the above. In other words, even when the conductor on the inner side of the copper layer of the outer terminal contracts greatly due to a decrease in the ambient temperature, the aluminum layer on the outer surface side of the crimping part contracts in the same manner as the conductor of the electric wire. It can be tightened from the outside. Therefore, it is possible to prevent the gap between the interface between the terminal and the conductor from being formed by the tightening force from the outside even when connected to the aluminum electric wire by the normal-strength crimping rather than over-crimping. As a result, stable crimping performance can be exhibited even under the expected heat cycle or thermal shock conditions. In addition, since there is no need for over-compression, there is no risk of lowering the mechanical strength, and the problem of conductor breakage can be avoided. Moreover, since the copper layer with high electrical conductivity is disposed on the inner surface portion that is in contact with the conductor of the electric wire and the aluminum layer is disposed on the outer surface, the electrical resistance of the connection portion with the electric wire can be reduced. Moreover, since it is not comprised only with an aluminum layer but the crimping | compression-bonding part is comprised at least by the laminated board material with a copper layer, it is also possible to improve spring property compared with an aluminum terminal.

  According to the second aspect of the present invention, it is possible to achieve a crimped connection with a stable contact resistance regardless of a temperature change by simply crimping a pair of crimping pieces of a crimping part having a normal U-shaped cross section to a conductor. .

  According to the invention of claim 3, since the outer aluminum layer is set to have a thickness equal to or larger than the copper layer, it is possible to sufficiently exert the tightening force to the copper layer at a low temperature, and to stabilize the contact resistance, thereby to improve the connection reliability. It can contribute to improvement of property.

  According to invention of Claim 4, since the whole terminal was comprised by the laminated board material of the aluminum layer and the copper layer, processing cost can be reduced.

  According to the invention of claim 5, since only the crimping part is constituted by the laminated plate material of the aluminum layer and the copper layer and the other part is constituted only by the copper layer, the performance of the entire terminal is maintained equal to the copper terminal. However, the performance of the crimp connection part can be improved.

  According to the sixth aspect of the present invention, stable contact resistance can be maintained regardless of temperature changes.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a structure of a portion where the crimp terminal of the embodiment is crimped to a conductor of an aluminum electric wire, FIG. 1 (a) is a diagram showing a state at normal temperature, and FIG. 1 (b) is about −40 ° C. FIG. 2A is an external perspective view of the crimp terminal according to the embodiment, and FIG. 2B is a perspective view illustrating a configuration of a laminated plate material constituting the crimp terminal. .

  The crimp terminal 10 for an aluminum wire according to this embodiment is connected by crimping to a terminal portion of an aluminum wire for a wire harness used in an automobile, and has copper or copper on the inner surface side in contact with the conductor Wa of the aluminum wire. The whole is constituted by a laminated plate material P in which a copper layer Pa made of an alloy is arranged and an aluminum layer Pb made of aluminum or an aluminum alloy is arranged on the outer surface side. The laminated sheet material P is manufactured by clad rolling and has a bimetallic structure. Here, the thickness of the aluminum layer Pb is set to be equal to or greater than the thickness of the copper layer Pa.

  As shown in FIG. 2A, the crimp terminal 10 of the embodiment has an electrical connection portion 11 at the front portion and a crimp portion 12 for crimping the conductor Wa of the aluminum electric wire at the rear portion. The crimping portion 12 is configured in a substantially U shape by a bottom plate 15 on which the conductor Wa is placed on the upper surface and a pair of crimping pieces 16, 16 extending upward from both side edges of the bottom plate 15. The crimp terminal 10 is formed so that the copper layer Pa comes to the inner surface side of the wire.

  In the case of the present embodiment, since the entire crimp terminal 10 is composed of the laminated plate material P of the copper layer Pa and the aluminum layer Pb, as shown in FIG. You may take it. That is, the material of the portion 12p that becomes the crimping portion and the portion 11p that becomes the electric wire connecting portion may be taken at any position.

  The use temperature range of the wire harness of the automobile is in the range of −40 ° C. to 120 ° C., and the material of the conductor Wa of the aluminum electric wire is aluminum or aluminum alloy. The linear expansion coefficient of the conductor Wa of the aluminum wire and the aluminum layer Pb of the crimp terminal 10 is larger than the linear expansion coefficient of the copper layer Pa of the crimp terminal 10. For this reason, the conductor Wa and the aluminum layer Pb are more likely to undergo thermal contraction and thermal expansion with respect to changes in ambient temperature than the copper layer Pa.

  The aluminum electric wire has a conductor Wa made of aluminum or an aluminum alloy covered with an insulating coating (not shown). When the crimp terminal 10 of this embodiment is connected to the aluminum electric wire, the end of the aluminum electric wire is connected. The crimping portion 12 of the crimp terminal 10 is crimped and fixed to the conductor Wa that is peeled off and exposed. At that time, under a normal temperature environment, the pair of crimping pieces 16 and 16 are bent inward so as to wrap the conductor Wa placed on the bottom plate 15 and crimped to the conductor Wa, thereby being crimped to the conductor Wa of the aluminum electric wire.

  Thus, when the crimp terminal 10 for aluminum electric wires of this embodiment is connected to an aluminum electric wire, the crimp part 12 is an aluminum electric wire rather than the terminal (copper terminal) comprised only with the copper layer with respect to the change of ambient temperature. The contraction and the expansion are repeated with a tendency to be close to the conductor Wa. That is, even when the conductor temperature Wa on the inner side of the copper layer Pa of the outer crimping terminal 10 is greatly contracted due to a decrease in the ambient temperature, the aluminum layer Pb on the outer surface side of the crimping portion 12 becomes the conductor Wa of the wire. Since it shrinks equally, the copper layer Pa can be tightened with a force (arrow) from the outside, as shown in FIG.

  Therefore, even when the aluminum wire is connected by normal strength crimping instead of over-crimping, the gap between the crimp terminal 10 and the conductor Wa can be prevented by the tightening force (arrow) from the outside. it can. Therefore, the contact resistance between the conductor Wa and the crimp terminal 10 can be stabilized, and stable crimp performance can be exhibited even under the expected heat cycle or thermal shock conditions. In particular, in this embodiment, only a pair of crimping pieces 16 and 16 of the crimping part 12 having a normal U-shaped cross section is crimped to the conductor Wa, thereby achieving a stable crimped connection with contact resistance regardless of temperature changes. be able to.

  In addition, since there is no need for over-compression, there is no risk of lowering the mechanical strength, and the problem of the conductor Wa being cut can be avoided. Moreover, since the copper layer Pa with high conductivity is arranged on the inner surface portion that contacts the conductor Wa of the electric wire and the aluminum layer Pb is arranged on the outer surface, the electric resistance of the connection portion with the electric wire can be reduced. . Moreover, since the whole terminal is comprised not only by the aluminum layer Pb but the laminated board material P with the copper layer Pa, it is also possible to improve spring property compared with an aluminum terminal.

  Moreover, in this embodiment, since the outer aluminum layer Pb is set to a thickness equal to or greater than the copper layer Pa, the clamping force for the copper layer Pa at a low temperature can be sufficiently exerted, and the contact resistance is stabilized. This can contribute to improvement of connection reliability.

  Moreover, since the whole terminal is comprised by the laminated board material P of the aluminum layer Pb and the copper layer Pa, reduction of processing cost can be aimed at.

  In the above-described embodiment, the case where the entire terminal is configured by the laminated plate material P of the copper layer Pa and the aluminum layer Pb is shown. However, at least the crimping part 12 may have a laminated structure of the copper layer Pa and the aluminum layer Pb. In this case, the effect of stabilizing the contact resistance can be obtained.

  Therefore, it is also possible to configure only the crimping portion with a laminated plate material of an aluminum layer and a copper layer and configure the other portion with a single layer material consisting of only a copper layer.

  For example, as shown in FIG. 3, when material is taken from the plate material P for the portion 10 p serving as the crimp terminal, only the portion 12 p serving as the crimp portion is removed from the laminated portion of the copper layer Pa and the aluminum layer Pb, The material of the part 11p, etc., which becomes the electrical connection part, is taken up by a single layer part of only the copper layer Pa. By doing so, only the pressure-bonding portion 12 can have a laminated structure of the copper layer Pa and the aluminum layer Pb. In addition, as the plate material P for taking the material in this way, it is only necessary to manufacture a single layer of the copper layer Pb, in which only a part of the aluminum layer Pb is laminated.

  Alternatively, the entire structure may be made of a single-layer plate material consisting of only the copper layer Pa, and the aluminum layer Pb may be joined to the outer surface of the portion that becomes the crimping portion later.

  In any case, when the parts other than the crimping part 12 are made of a single layer material consisting of only the copper layer Pa, the performance of the crimping connection part can be improved while maintaining the performance of the entire terminal equivalent to that of the copper terminal. Can be planned.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structure of the part which crimped | bonded the crimp terminal of embodiment of this invention to the conductor of the aluminum electric wire, (a) is a figure which shows the state at the time of normal temperature, (b) is force at the time of the low temperature of about -40 degreeC. It is a figure for showing such a direction. (A) is an external appearance perspective view of the crimp terminal of embodiment, (b) is a perspective view which shows the structure of the laminated board material which comprises a crimp terminal. It is a perspective view which shows the mode of the material removal for manufacturing the crimp terminal of other embodiment of this invention. It is explanatory drawing of the crimping connection part by the conventional crimp terminal, (a) is the state at the time of crimping | crimping at normal temperature, (b) is the state at the time of high temperature, (c) is the schematic cross section of the crimping | compression-bonding part which respectively shows the state at the time of low temperature FIG.

Explanation of symbols

Wa Conductor of aluminum electric wire 10 Crimp terminal for aluminum electric wire 12 Crimp part 15 Bottom plate 16 Crimp piece P Laminated plate material Pa Copper layer Pb Aluminum layer

Claims (6)

  A copper layer made of copper or a copper alloy on the inner surface side where at least the crimping portion is in contact with the conductor, the crimping portion being crimped so as to be wrapped from the outside with respect to the aluminum or aluminum alloy conductor of the aluminum electric wire A crimp terminal for an aluminum electric wire, characterized in that it is made of a laminated plate material in which an aluminum layer made of aluminum or an aluminum alloy is arranged on the outer surface side. The press contact terminal for an aluminum wire according to claim 1,
The crimping portion is a bottom plate on which the conductor is placed on the top surface, and a pair of crimps that are crimped to the conductor by being bent inward so as to wrap around the conductor placed on the bottom plate, extending from both side edges in the width direction of the bottom plate. A crimp terminal for an aluminum electric wire, characterized in that it is formed in a substantially U shape with a piece. A crimp terminal for an aluminum electric wire according to claim 1 or 2,
A crimp terminal for an aluminum electric wire, wherein at least the thickness of the aluminum layer is set to be equal to or greater than the thickness of the copper layer. It is a crimp terminal for aluminum electric wires according to any one of claims 1 to 3,
The crimp terminal for an aluminum electric wire, characterized in that the entire terminal is composed of a laminated plate material of the aluminum layer and the copper layer. It is a crimp terminal for aluminum electric wires according to any one of claims 1 to 3,
Only the said crimping | compression-bonding part is comprised by the laminated board material of the said aluminum layer and a copper layer, and the other part is comprised by the single-layer board | plate material only of a copper layer, The crimp terminal for aluminum electric wires characterized by the above-mentioned. A crimping structure using the crimp terminal for an aluminum electric wire according to any one of claims 1 to 5,
A crimping structure using a crimping terminal for an aluminum wire, wherein the crimping portion of the crimping terminal for the aluminum wire is crimped so as to be wrapped from the outside to an aluminum or aluminum alloy conductor of the aluminum wire.

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