JP6622961B2 - Wire connection structure and wire connection method - Google Patents

Description

  The present invention relates to, for example, an electric wire connection structure and an electric wire connection method for electrically connecting conductor exposed portions in which a conductor is exposed by peeling off the tip side of an insulating coating in a covered electric wire in which a conductor is covered with an insulating coating.

  In recent years, automobiles are equipped with various electrical devices that improve operability and comfort, and such electrical devices are connected to each other by wire harnesses arranged in the automobile to transmit / receive signals and transmit power. Supplying.

  Among the plurality of covered electric wires constituting the above-described wire harness, there is one in which conductor exposed portions of the covered electric wires are connected to be conductive by a connecting member. For example, a joint structure described in Patent Document 1 is used. Proposed.

  The joint terminal (connecting member) described in Patent Document 1 is an open barrel type terminal, and has a crimping piece in a crimping portion that crimps and connects a covered electric wire. And it is supposed that the conductor exposed parts can be connected to each other in a conductive manner by folding back the crimped pieces in the direction of the conductor exposed parts and collectively crimping the conductor exposed parts of the plurality of covered electric wires.

  By the way, wire harnesses that are connected and routed to electrical equipment should be routed to new electrical equipment when the electrical equipment is added to improve operability and comfort. The weight of the wire harness increases.

  However, it is required to reduce the weight of the wire harness from the viewpoint of improving fuel efficiency, and as one of countermeasures, a wire harness using a conductor made of an aluminum-based material has been proposed.

  Since the aluminum-based material has an oxide film formed on the surface thereof, the conductivity with other members in contact with the aluminum-based material is significantly reduced. Therefore, a wire harness constructed using an aluminum-based material must destroy the oxide film in order to ensure conductivity.

  For the destruction of the oxide film, it is desirable to weld the exposed conductor portions, but when welding the exposed conductor portion composed of an aluminum-based material, using an open barrel type joint terminal as described in Patent Document 1, There is a possibility that a welding jig or the like for welding the exposed conductor portion and the molten exposed conductor portion may come into contact with each other and be fixed.

JP-A-9-129275

  Accordingly, the main object of the present invention is to provide an electric wire connection structure and an electric wire connection method in which conductor exposed portions are welded and connected so that the welding jig and the conductor exposed portion do not come into contact with each other and are fixed.

The present invention includes a plurality of covered electric wires having a conductor exposed portion in which a conductor is covered with an insulating coating, and the conductor is exposed by stripping a leading end side of the insulating coating to a predetermined length. A connection member formed in a ring shape in cross section, and a plurality of exposed conductor portions connected in a conductive manner, wherein the conductor in at least one of the covered wires is an aluminum-based structure. In addition to an aluminum conductor made of a material, the connecting member is made of a material having a melting point higher than that of the aluminum conductor , and the length of the connecting member in the axial direction is 3 minutes of the length of the exposed conductor. 1 to 4/5 or less, and the short connection member is located at a position where the distal end of the insulation coating and the proximal end of the short connection member are separated from the covered electric wire. It is location, and a plurality of said conductor exposed portion inserted inside the short-length connecting member and said short-length connecting member, the cross-sectional shape, a substantially oval diameter equivalent to the width of the short-length connecting member before bonding In the welded state of the conductor exposed portion and the short connection member, the tip exposed portion where the tip of the conductor exposed portion is exposed from the tip of the short connecting member and the diameter is not reduced by pressure bonding. It is the electric wire connection structure in which is formed .

The connecting member may be, for example, a circular cross section, a rectangle, or a polygon as long as it has a circular cross section that allows insertion of a plurality of exposed conductor portions.
The aluminum-based material is a material containing aluminum or an aluminum alloy.
The welding is a concept of welding exposed portions of conductors by ultrasonic welding, electric resistance welding, laser welding, or the like.

The plurality of covered electric wires are configured by bundling a covered electric wire having a conductor made of copper or a copper alloy and a covered electric wire having an aluminum conductor if at least one of the covered electric wires has an aluminum conductor. Alternatively, only covered electric wires having an aluminum conductor may be bundled.
The above-mentioned pressure welding is a concept including welding after the conductor exposed portion and the connection member are pressure-bonded, or pressure bonding while welding.

  According to the present invention, the conductor exposed portions and the conductor exposed portions and the connection member are welded without the welding jig for welding the conductor exposed portions and the connecting member and the molten conductor exposed portions coming into contact with each other and being fixed. be able to.

  In detail, the aluminum-based material has a melting point and a softening point close to each other, and there is a possibility that a part of the aluminum conductor is melted by welding, but the conductor exposed portion is inserted into the connection member formed in an annular cross section, By interposing the connecting member between the conductor exposed portion and the welding jig, the conductor exposed portion and the welding jig do not come into contact with each other, and the conductor exposed portion and the welding jig can be prevented from being fixed.

  In addition, since the connecting member is made of a material having a melting point higher than that of the aluminum conductor, the connecting member is not melted even if the exposed conductor is melted, so that the exposed conductor and the welding jig are securely fixed. Can be prevented.

If the connecting member is not circular in cross section, such as an open barrel type, part of the exposed conductor protrudes unintentionally from other than the distal end and the base end of the connecting member when the exposed conductor is connected to the connecting member. Although there is a possibility, the connection member formed in the annular cross section can surely prevent the conductor exposed portion from protruding from other than the tip end portion and the base end portion of the connection member in the connection state between the conductor exposed portion and the connection member.
Therefore, since the conductor exposed portion is reliably held inside the connection member, the conductor exposed portion and the connection member can be reliably conducted.

  Furthermore, aluminum-based materials including aluminum and aluminum alloys have a lower specific gravity than copper-based materials including copper and copper alloys that constitute the conductors of general coated wires, and therefore bundle a plurality of coated wires composed of aluminum conductors. The wire harness configured as described above can be reduced in weight efficiently.

  Further, the conductor exposed portion and the connecting member are connected so that the conductor exposed portion and the connecting member are in close contact by welding the conductor exposed portion and the connecting member to each other by crimping the conductor exposed portion and the connecting member. can do.

  More specifically, since the connecting member is formed in a size that allows insertion of a plurality of exposed conductors, a gap is formed between the exposed conductor and the connecting member, and the exposed conductor is connected to the exposed conductor by this gap. There is a possibility that the member is not reliably welded.

However, since the conductor exposed portion and the connection member are welded while being crimped so as to crush the gap between the conductor exposed portion and the connection member by performing crimp welding involving crimping, the electric wire connection structure has a conductor exposed portion. And a connection state in which the connection member is in close contact with each other.
Therefore, the conductor exposed portion and the connection member can be reliably conducted.

Also, the connecting member, and short-length connecting member which the length in the axial direction is 4 or less of one or more 5-minute-third of the length of the exposed conductor portion, with respect to the coated electric wire, the insulating coating may be the tip of the base end of said short-length connecting member is more the short-length connecting member and arranged child at a position spaced apart, to ensure conductivity between the conductor exposed portion and the short-length connecting member.

In detail, a plurality of conductor exposed portion to be compressed and pressed with short-length connecting member in compression state between the short-length connecting member, since the direction of short-length connecting member side is reduced in diameter than the coated wire side A wire diameter difference is generated between a plurality of conductor exposed portions bundled on the covered wire side and a plurality of conductor exposed portions bundled on the short connecting member side.

When the exposed conductor and the short connection member are crimped so that the distal end of the insulation coating and the proximal end of the short connection member are in close contact with each other, it is positioned at the boundary between the insulation coating and the short connection member due to the above-described wire diameter difference. The exposed conductor portion may be disconnected due to abrupt diameter reduction, and it may not be possible to obtain reliable conductivity between the exposed conductor portions.

However, the length of the short connecting member in the axial direction is set to 4/5 or less of the length of the exposed conductor, and the distal end of the insulating coating and the proximal end of the short connecting member are separated from the covered electric wire. by disposing the short-length connecting member to a position, the conductor exposed portion located between the insulating coating and the short-length connecting member at the compression bonding state, only spaced minute for gradually reduced in diameter, the electrical characteristics It is possible to prevent the conductor from being changed or to prevent the conductor exposed portion from being disconnected, and to reliably obtain the conductivity between the conductor exposed portions.

On the other hand, since the length in the axial direction of the short connection member is set to one third or more of the length of the conductor exposed portion, the short connection member is damaged along with the crimping, or the conductor exposed portion and the short shape are short. in crimping state of the connecting member without the short-length connecting member by pulling the conductor exposed portion is damaged, it is possible to obtain a stable connection between the conductor exposed portion and the short-length connecting member, the conductor exposed A contact area sufficient to ensure stable conductivity between the portions and the short connection member can be obtained.

Also, in the welding state between the short-length connecting member and the conductor exposed portion, the tip from the tip of the conductor exposed portion of the short-length connecting member is exposed to form the distal exposed portion which is not reduced in diameter by crimping more and this, it is possible to maintain a connection state between the conductor exposed portion and the short-length connecting member.

In detail, when crimped and the short-length connecting member conductor exposed portion, but the conductor exposed portion of the insertion portion into short-length connecting member is reduced in diameter by crimping, distal exposed portion which is exposed from the short-length connecting member Crimping because they are not reduced in diameter by, even if pull the conductor exposed portion that is connected to short-length connecting member, caught on the tip of the distal end exposed portion which is not reduced in diameter is contracted short-length connecting member, the conductor exposed portion is short-length The connection state between the conductor exposed portion and the short connection member can be maintained without coming out of the connection member.

Furthermore, by forming the exposed tip, the exposed conductor is reliably connected to the entire inner surface of the short connecting member, so the electrical resistance value between the exposed conductor and the short connecting member is increased. It is possible to suppress this, and to obtain excellent conductivity.

As an aspect of the present invention, the short connecting member can be made of a material having a copper purity of 60% or more.
According to the present invention, the deformability of the short connection member can be further improved.

In detail, when the purity of the copper improves toughness in the short elongate connecting member by constituting a short-length connecting member in more than 60% of the material, crimping and the short-length connecting member exposed conductors, short it is possible to more easily deformed Jo connecting member, the trouble such as cracks or cracks due to the deformation of the short elongated connecting member is caused to short-length connecting member upon crimping and the short-length connecting member exposed conductors Can be further suppressed.

Note that a short connection member made of brass, tough pitch copper, oxygen-free copper, or the like, which is a copper-based material having a copper purity of 60% or more, has a higher melting point than a short connection member made of an aluminum-based material. When welding the conductor exposed portion and the short connecting member, even if the conductor exposed portion melts, the short connecting member is not melted, and the conductor exposed portion can be prevented from being fixed to the welding jig.

According to the present invention, a plurality of conductor exposed portions, in which the conductor is exposed by peeling a predetermined length of the leading end side of the insulating coating in a covered electric wire having a conductor coated with an insulating coating, are arranged inside a connection member formed in an annular cross section. The conductor exposed portion and the connecting member are welded using a welding jig so as to be conductive, and at least one of the covered electric wires having an aluminum conductor made of an aluminum-based material is used. And the connecting member is made of a material having a melting point higher than that of the aluminum conductor , and the connecting member has a length in the axial direction of not less than one-third and not more than four-fifth of the length of the exposed conductor. a short-length connecting member and the relative covered electric wire, the tip of the insulating coating and the base end of said short-length connecting member placing the short-length connecting member at a position spaced apart plurality of said conductors dew Parts and the said short-length connecting member, in a cross section perpendicular to the axial direction of the short-length connecting member, a direction intersecting the crimping direction for crimping said short elongate connecting member, said short-length connecting member before compression short In the welded state between the exposed conductor and the short connection member, the short connection member is welded while being crimped so that the cross-sectional shape is substantially elliptical while being regulated to a width equal to the diameter of the connection member . The wire connecting method is characterized in that the tip of the conductor exposed portion is exposed from the tip of the short connection member, and a tip exposed portion that is not reduced in diameter by crimping is formed .

  According to the present invention, the conductor exposed portions and the conductor exposed portions and the connection member are brought into close contact with each other without the welding jig for welding the conductor exposed portions and the connection member and the melted conductor exposed portions coming into contact and fixing. It can be welded while crimping so as to be integrated.

Further, the connecting member is a short connecting member having a length in the axial direction of 1/3 or more and 4/5 or less of the length of the conductor exposed portion, By disposing the short connection member at a position where the distal end and the base end of the short connection member are separated from each other, a gap is provided between the short connection member and the insulating coating so that the conductivity of the conductor exposed portion is increased. Can be secured.

Also, in a cross section perpendicular to the axial direction of the short-length connecting member, a direction intersecting the crimping direction for crimping the short-length connecting member, said short-length connecting member equivalent to the diameter of the short-length connecting member before bonding more the short-length connecting member while regulated and child crimped width, in a cross section perpendicular to the axial direction of the short-length connecting member, and greatly deformed in a direction in which the short-length connecting member crossing the crimping direction, crimp Since the subsequent shape can be prevented from becoming a flat shape, it is possible to suppress the occurrence of cracks or cracks in the short connection member.
Therefore, the conductor exposed portion and the short connection member can be reliably connected and made conductive.

Also, in the welding state between the short-length connecting member and the conductor exposed portion, the tip of the exposed conductor portion from the tip of the short-length connecting member is exposed, forming child a distal exposed portion which is not reduced in diameter by crimping more bets can be maintained a connection state between the exposed conductor portion and the short-length connecting member.

In an embodiment of the present invention, the purity of the copper can be carried out using the short-length connection member configured with more than 60% of the material.
According to the present invention, the deformability of the short connection member can be further improved.

As an aspect of the present invention, the plurality of exposed conductor portions to be inserted into the short connection member are arranged in a substantially circular shape, and the total cross-sectional area is 20% or more of the internal cross-sectional area of the short connection member. It can be formed to be 90% or less.

  According to the present invention, a conductor is covered with an insulating coating, and a plurality of covered electric wires having a conductor exposed portion where the conductor is exposed on the distal end side are formed in an annular cross section. An electric wire connection structure in which the connection member for inserting the conductor exposed portion is connected to be conductive, wherein the conductor in at least one of the covered electric wires is an aluminum conductor made of an aluminum-based material, and the connection The member is made of a material having a melting point higher than that of the aluminum conductor, the inserted conductor exposed portion and the connection member are connected by welding, and the inner edge of the insertion opening of the connection member is directed toward the base end side. And the enlarged inner edge is formed in an arc shape projecting toward the central axis in a cross section passing through the central axis of the connecting member. Together, characterized in that the radius of the arc-shaped for the expansion inner edge, an electrical connection structure was 1/2 or more of the plate thickness of the connecting member.

The gradually expanding enlarged inner edge is a concept including, for example, an enlarged inner edge in which the inner edge of the insertion opening is tapered in a cross section passing through the central axis of the connecting member.
According to the present invention, the conductor exposed portion is reliably and easily inserted into the connection member, and the welding jig for welding the conductor exposed portion and the connection member and the molten conductor exposed portion are not contacted and fixed. The conductor exposed portions and the conductor exposed portions and the connecting member can be welded.

More specifically, the inner edge of the insertion opening of the connecting member is an enlarged inner edge that gradually expands toward the base end side, so that when the conductor exposed portion is inserted into the connecting member, the conductor exposed portion becomes the base end of the connecting member. Even when abutting against the end face on the side, the enlarged inner edge guides the conductor exposed portion into the connection member, so that the conductor exposed portion can be reliably and easily inserted into the connection member.
Therefore, the conductor exposed portion and the connection member can be reliably conducted.

Further, the enlarged inner edge is formed in an arc shape projecting toward the central axis in a cross section passing through the central axis of the connection member, and the radius of the enlarged inner edge in the arc shape is set to a plate thickness of the connection member. When the connecting member having the arc-shaped enlarged inner edge and the conductor exposed portion are connected, the covered electric wire on the base end side of the connecting member is pulled in the radial direction of the connecting member. Even if it is made, since the covered electric wire and the connecting member do not hit each other, the covered electric wire can be prevented from being damaged.
Therefore, the conductor exposed portion and the connection member can be more reliably conducted.

  Further, as an aspect of the present invention, a bottomed cylindrical cap that is mounted so as to surround the connection member is provided, and the outer edge of the distal end portion that is the distal end side of the connection member is gradually reduced toward the distal end side. Reduced outer edge.

The above-mentioned bottomed cylindrical cap is a concept including a substantially cylindrical cap in which one axial direction is closed.
The gradually reducing outer edge is a concept including, for example, a reducing outer edge formed in an arc shape or a reducing outer edge formed in a tapered shape.

According to the present invention, it is possible to improve the water-stopping property of the wire connection structure, and it is possible to easily attach the insulating cap to the wire connection structure.
More specifically, the electric wire connection structure includes a bottomed cylindrical cap that is mounted so as to surround the connection member, thereby preventing moisture from entering the connection portion between the conductor exposed portion and the connection member. Therefore, the water stoppage of the wire connection structure can be improved.

  In addition, the bottomed cylindrical cap, for example, can hold and inject a silicon material or the like inside, thereby more reliably preventing moisture from entering the connecting portion between the conductor exposed portion and the connecting member. Thus, the water stoppage of the wire connection structure can be further improved.

Furthermore, the electric wire connection structure reliably and easily attaches the cap to the connection member by forming the outer edge of the tip portion, which is the tip side of the connection member, as a reduced outer edge that gradually decreases toward the tip side. be able to.
Therefore, the electric wire connection structure in which the cap is attached to the connecting member to improve the water-stopping property can reliably connect the covered electric wire and the connecting member so as to be conductive.

  According to the present invention, a conductor is covered with an insulating coating, and a plurality of covered electric wires having a conductor exposed portion where the conductor is exposed on the distal end side are formed in an annular cross section. An electric wire connection structure in which the connection member for inserting the conductor exposed portion is connected to be conductive, wherein the conductor in at least one of the covered electric wires is an aluminum conductor made of an aluminum-based material, and the connection The member is made of a material having a melting point higher than that of the aluminum conductor, the inserted conductor exposed portion and the connection member are connected by welding, and the inner edge of the insertion opening of the connection member is directed toward the base end side. And a bottomed cylindrical cap that is mounted so as to surround the connection member, and has a distal end portion that is the distal end side of the connection member An outer edge, and wherein the toward the distal end side is electrically connected structure was reduced outer edge which is gradually reduced.

  According to the present invention, the conductor exposed portion is reliably and easily inserted into the connection member, and the welding jig for welding the conductor exposed portion and the connection member and the molten conductor exposed portion are not contacted and fixed. The conductor exposed portions and the conductor exposed portions and the connecting member can be welded.

More specifically, the inner edge of the insertion opening of the connecting member is an enlarged inner edge that gradually expands toward the base end side, so that when the conductor exposed portion is inserted into the connecting member, the conductor exposed portion becomes the base end of the connecting member. Even when abutting against the end face on the side, the enlarged inner edge guides the conductor exposed portion into the connection member, so that the conductor exposed portion can be reliably and easily inserted into the connection member.
Therefore, the conductor exposed portion and the connection member can be reliably conducted.

  In addition, a bottomed cylindrical cap that is mounted so as to surround the connection member is provided, and the outer edge of the distal end portion that is the distal end side of the connection member is a reduced outer edge that is gradually reduced toward the distal end side. Thus, the water stoppage of the electric wire connection structure can be improved, and the insulating cap can be easily attached to the electric wire connection structure.

  More specifically, the electric wire connection structure includes a bottomed cylindrical cap that is mounted so as to surround the connection member, thereby preventing moisture from entering the connection portion between the conductor exposed portion and the connection member. Therefore, the water stoppage of the wire connection structure can be improved.

  In addition, the bottomed cylindrical cap, for example, can hold and inject a silicon material or the like inside, thereby more reliably preventing moisture from entering the connecting portion between the conductor exposed portion and the connecting member. Thus, the water stoppage of the wire connection structure can be further improved.

Furthermore, the electric wire connection structure reliably and easily attaches the cap to the connection member by forming the outer edge of the tip portion, which is the tip side of the connection member, as a reduced outer edge that gradually decreases toward the tip side. be able to.
Therefore, the electric wire connection structure in which the cap is attached to the connecting member to improve the water-stopping property can reliably connect the covered electric wire and the connecting member so as to be conductive.

  As an aspect of the present invention, the enlarged inner edge is formed in an arc shape protruding toward the central axis in a cross section passing through the central axis of the connecting member, and the radius of the arc-shaped enlarged inner edge is set to the connecting member. It is possible to make it more than half of the plate thickness.

According to the present invention, in a state where the connection member having the arc-shaped enlarged inner edge and the conductor exposed portion are connected, even if the covered electric wire on the base end side with respect to the connecting member is pulled in the radial direction of the connecting member, the covered electric wire Since the connection member does not hit the corner, the covered electric wire can be prevented from being damaged.
Therefore, the conductor exposed portion and the connection member can be more reliably conducted.

Further, as an aspect of the present invention, the plurality of conductor exposed portions and the connection member can be welded together by pressure bonding involving the crimping of the conductor exposed portions and the connection member.
According to the present invention, the conductor exposed portion and the connection member can be connected so as to be in close contact with each other.
Therefore, the conductor exposed portion and the connection member can be more reliably conducted.

As an aspect of the present invention, in the connection member before crimping, a portion to be crimped to the conductor exposed portion can be a conductor crimping portion having a smaller cross section than a coated crimping portion to crimp the insulating coating.
According to this invention, the conductor exposed portion and the connecting member are connected so as to be in close contact with each other without damaging the connecting member, and the conductivity between the conductor exposed portion and the connecting member can be ensured.

  More specifically, the coated crimping part to be crimped to the insulation coating coated on the conductor has a larger wire diameter than the conductor crimping part to be crimped to the conductor exposed part, so the cross section of the conductor crimping part and the coated crimping part were formed equally. When crimping the connection member and the covered electric wire, the conductor crimping part may be damaged due to an increased amount of deformation than the coated crimping part, but the part to be crimped to the conductor exposed part is crimped to the insulation coating. By making the conductor crimping portion smaller than the cross section, it is possible to suppress an increase in the deformation amount of the conductor crimping portion and to prevent the connection member from being damaged. Can be secured.

As an aspect of the present invention, in the crimped state, the thickness of the inserted conductor exposed portion can be set to one third or more of the thickness of the connection member.
The thickness of the exposed conductor and the thickness of the connecting member are concepts including the thickness of the exposed conductor and the minimum outer diameter of the connecting member when the crimped shape is elliptical in cross section.

  By this invention, it is possible to prevent the aluminum conductor composed of an aluminum-based material having a melting point lower than that of copper generally used for the conductor and easily melted from being melted when the conductor exposed portion and the connection member are welded, The conductor exposed portion including the aluminum conductor and the connection member can be reliably connected.

As an aspect of the present invention, the inserted conductor exposed portion may have a sectional area of 90% or less of the sectional area inside the connecting member.
According to the present invention, the conductor exposed portion can be more reliably and easily inserted into the connection member.

  Specifically, by setting the cross-sectional area of the inserted conductor exposed portion to 90% or less of the cross-sectional area inside the connection member, the tip of the conductor exposed portion abuts the outer edge of the insertion opening in the connection member, The exposed conductor can be prevented from jumping out of the connecting member or scattered inside the connecting member, and the exposed conductor can be inserted into the connecting member more reliably and easily. Can be improved.

  In consideration of performing welding with pressure bonding, it is desirable that the cross-sectional area of the entire conductor exposed portion is 20% or more of the cross-sectional area inside the connecting member. As a result, the connection member can be connected so as to reduce the amount of deformation when crimping to the conductor exposed portion and prevent damage, and to be in close contact with the conductor exposed portion without any gaps. Can be further improved.

  More preferably, the cross-sectional area of the entire conductor exposed portion is 40% to 70% of the cross-sectional area inside the connection member. Thereby, since the insertability of the conductor exposed part into the inside of the connection member and the adhesion between the connection member and the conductor exposed part can be further improved, the conductivity of the wire connection structure is further improved. Can do.

Further, as an aspect of the present invention, it is possible to provide a closing portion that closes the tip portion that is the tip side of the connection member.
According to the present invention, it is possible to reliably prevent the welding jig and the conductor exposed portion from coming into contact with each other, and improve the water-stopping property of the electric wire connection structure.

  In detail, the electric wire connection structure is provided with a blocking portion on the distal end side of the connection member, so that a part of the molten aluminum conductor melts from the distal end side of the connection member and does not contact the welding jig. The exposed conductors can be connected to each other, and it is possible to reliably prevent moisture from entering the connecting member connected to the exposed conductors from the tip side, thereby improving the water stoppage of the wire connection structure. it can.

  Moreover, in order to improve the water-stopping property of the wire connection structure, for example, even when silicon material is injected into the connection member from the insertion opening, the silicon material is prevented from flowing down from the front end side of the connection member. And since the water stop of the base end side of a connection member can be ensured, the water stop of a wire connection structure can further be improved.

  The present invention can provide a wire connection structure and a wire connection method in which conductor exposed portions are welded and connected so that the welding jig and the conductor exposed portion do not come into contact with each other and are fixed.

The perspective view showing an electric wire connection structure. The exploded perspective view showing a covering electric wire and a connecting terminal. Sectional drawing showing the covered electric wire and connecting terminal before an electric wire insertion process. Sectional drawing showing the covered electric wire and connecting terminal before an electric wire connection process. Sectional drawing showing the electric wire connection structure after an electric wire connection process. The graph explaining an electrical resistance measurement test. The graph explaining an electrical resistance measurement test. The graph explaining a tension test. Sectional drawing showing the conventional electric wire connection structure. Sectional drawing showing the covered electric wire and connection terminal before the electric wire insertion process in 2nd Embodiment. Explanatory drawing explaining an electric wire connection structure. Sectional drawing showing the covered electric wire and connection terminal before the electric wire insertion process in 3rd Embodiment. Explanatory drawing explaining an electric wire connection structure. Explanatory drawing explaining the connection terminal in other embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a perspective view of the electric wire connection structure 10, FIG. 2 shows an exploded perspective view of the covered electric wire 20 and the connection terminal 30, and FIG. 3 shows the connection with the covered electric wire 20 before the electric wire insertion step. The longitudinal cross-sectional view with the terminal 30 is shown.

  Fig.4 (a) shows the longitudinal cross-sectional view of the covered electric wire 20, the connection terminal 30, and the crimp welding apparatus 40 before an electric wire connection process, FIG.4 (b) is the AA line in Fig.4 (a). FIG. 5A shows a longitudinal sectional view of the covered electric wire 20, the connection terminal 30, and the electric wire connection device 40 after the electric wire connection process, and FIG. 5B shows the inside of FIG. The BB sectional drawing of FIG.

  FIG. 6 shows a graph of the result of an electrical resistance measurement test performed using the wire connection structure 10 formed by crimping and welding the connection terminal 30 and the conductor exposed portion 23 made of tough pitch copper, and FIG. The graph of the result of the electrical resistance measurement test performed using the electric wire connection structure 10 comprised by crimping | bonding the connection terminal 30 comprised with the brass and the conductor exposure part 23 was shown, and FIG. 8 comprises oxygen-free copper The graph of the result of the tension test done using the electric wire connection structure 10 comprised by crimping | bonding and welding the connection terminal 30 and the conductor exposed part 23 was shown. FIG. 9 shows a longitudinal sectional view of a conventional wire connection structure 10.

  As shown in FIG. 1, the wire connection structure 10 in the first embodiment includes seven covered wires 20 and connection terminals 30 that connect the covered wires 20 to each other. The terminals 30 are welded while being crimped using a wire connecting device 40 described later, and the covered wires 20 and the connection terminals 30 are connected so as to be conductive.

  One side in the longitudinal direction X of the covered electric wire 20 is the tip end side Xa, the other is the other end side Xb, and the direction in which the covered electric wire 20 and the connection terminal 30 are crimped by the electric wire connecting device 40 is the crimping direction Z. A direction perpendicular to the longitudinal direction X and the crimping direction Z is defined as a width direction Y.

As shown in FIG. 2, the covered electric wire 20 includes an insulating conductor 22 made of a synthetic resin having an insulating property, an aluminum conductor 21 formed by bundling a plurality of aluminum wires made of an aluminum-based material containing aluminum or an aluminum alloy. And a conductor exposed portion 23 in which the aluminum conductor 21 is exposed by peeling the tip end side Xa of the insulating coating 22 by a predetermined length.
In addition, although the length in the axial direction of the conductor exposed part 23 in 1st Embodiment shall be 15 mm and a wire diameter shall be 0.75 sq, it does not restrict only to this.

  The connection terminal 30 is formed by forming a tough pitch copper plate having a plate thickness of 0.3 mm into a hollow shape with a circular cross section. And this connection terminal 30 sets the length in the longitudinal direction X to 8 mm which is 1/3 or more and 4/5 or less of the length of the conductor exposure part 23, and an internal diameter is set to 7 covered electric wires 20 Are formed to be slightly larger than the conductor exposed portion 23 bundled in parallel.

  Since tough pitch copper is a material having a copper purity of 60% or higher and a melting point higher than that of aluminum, it can be easily deformed by pressure bonding and can be connected even when the conductor exposed portion 23 reaches a melting temperature. The terminal 30 does not melt.

  The conductor exposed portion 23 in which the seven covered electric wires 20 are bundled is inserted into the connection terminal 30 so that the tip of the conductor exposed portion 23 is exposed 1 mm from the tip end side Xa of the connection terminal 30. 23 and the connection terminal 30 are welded while being crimped from the crimping direction Z using the wire connection device 40, and the exposed end portion 24 where the conductor exposed portion 23 is exposed from the connecting terminal 30 on the distal end side Xa. To form the connection structure 10 in which the conductor exposed portions 23 and the connection terminals 30 are connected to be conductive.

The number of the covered electric wires 20 is not limited to seven as long as it is two or more. For example, four covered electric wires 20 or eight electric wires may be bundled.
Furthermore, the length of the tip exposed portion 24 exposed from the tip of the connection terminal 30 is not limited to 1 mm, and a desired predetermined length may be set as appropriate.

The wire connection structure 10 configured as described above is configured by performing the wire insertion step and the wire connection step in this order.
First, the electric wire connection apparatus 40 used for an electric wire connection process is demonstrated.

As shown in FIG. 4, the wire connecting device 40 includes an upper mold 41 and a lower mold 42 that are opposed to the connection terminal 30 so as to be separated from each other in the vertical direction. It is configured to be movable in the crimping direction Z by means.
Note that not only the upper die 41 but also the lower die 42 may be configured to be movable in the crimping direction Z.

  As shown in FIGS. 4 and 5, the upper die 41 is formed to have a width equal to the diameter of the connection terminal 30 in a cross section orthogonal to the longitudinal direction X, and is crimped so as to crush the connection terminal 30 from above. The upper die crimping portion 43 is provided at the lower end portion, and an electrode (not shown) is provided at the center of the upper die crimping portion 43.

The lower die 42 includes a lower die crimping portion 44 having a concave cross section formed at a width equal to the diameter of the connection terminal 30 in the cross section perpendicular to the longitudinal direction X, and an electrode (not shown) is provided on the lower die crimping portion 44. In the middle of.
The lower die crimping portion 44 is configured so that the connection terminal 30 can be disposed.

  The electric wire connecting device 40 having the upper die 41 and the lower die 42 configured as described above is illustrated while the conductor exposed portion 23 and the connection terminal 30 are being crimped by the upper die crimping portion 43 and the lower die crimping portion 44. It is the structure which can perform the crimping | compression-bonding welding welded by the electrode which does not.

Then, the electric wire insertion process and electric wire connection process in the manufacturing method which manufactures the electric wire connection structure 10 are demonstrated.
The electric wire insertion step is a step of inserting the conductor exposed portion 23 of the covered electric wire 20 into the connection terminal 30 as shown in FIGS. 3 and 4.

  More specifically, as shown in FIG. 3, the connection terminal 30 is arranged on the tip end side Xa of the seven covered electric wires 20 bundled in parallel, and the conductor exposed portion 23 is arranged inside the connection terminal 30 as shown in FIG. 4. The conductor exposed portion 23 is inserted so that the tip of the conductor exposed portion 23 is exposed 1 mm from the tip of the connection terminal 30.

  Since the covered electric wire 20 and the connection terminal 30 after the completion of the electric wire insertion process are configured as described above, a slight gap is generated between the conductor exposed portion 23 and the connection terminal 30 in the seven covered electric wires 20. By disposing the connection terminal 30 at a position where the tip of the insulating coating 22 and the other end of the connection terminal 30 are separated from the covered wire 20, the tip exposed portion 24 is exposed by 1 mm from the tip of the connection terminal 30. Yes.

  As shown in FIGS. 4 and 5, the wire connecting step is a step in which the conductor exposed portions 23 of the seven covered wires 20 inserted into the connection terminals 30 are conductively connected by the wire connecting device 40 described above. is there.

  More specifically, as shown in FIG. 4, the connection terminal 30 in which the conductor exposed portion 23 is inserted is disposed on the lower die crimping portion 44 of the lower die 42 constituting the wire connecting device 40, and is spaced above the lower die 42. The upper die 41 thus arranged is moved toward the lower die 42, and the conductor exposed portion 23 and the connection terminal 30 of the covered electric wire 20 are sandwiched between the upper die 41 and the lower die 42 as shown in FIG. And crimping with a pressure of 0.6 bar.

  When crimping, the lower mold 42 is crimped by the lower mold crimping portion 44 while restricting movement of the conductor exposed portion 23 and the connection terminal 30 in the width direction Y, and the upper die 41 and the lower die 42 are provided. A current is passed through the conductor exposed portion 23 and the connection terminal 30 of the covered electric wire 20 by an electrode (not shown), and the conductor exposed portion 23 and the connection terminal 30 are welded by electric resistance heat generated accordingly.

  The electric wire connection structure 10 after the electric wire connection process has the conductor exposed portion 23 and the connection terminal 30 welded by regulating the width direction Y so that the cross-sectional shape in the connection terminal 30 portion is as shown in FIG. Furthermore, it is formed in a substantially elliptical shape that is long in the width direction Y.

  Furthermore, in the electric wire insertion process, by arranging the covered electric wire 20 and the connection terminal 30 as described above, the distal end exposed portion 24 formed on the distal end side Xa of the connection terminal 30 after the electric wire connection process is connected to the connection terminal 30. The wire diameter of the tip exposed portion 24 gradually increases from the tip of the connection terminal 30 toward the tip side Xa because the conductor exposed portion 23 inserted inside the wire is not firmly crimped. .

The effect of the electric wire connection structure 10 comprised by performing crimp welding as mentioned above is demonstrated.
The wire connection structure 10 in the first embodiment has a circular cross section and a hollow shape in which seven covered electric wires 20 having aluminum conductors 21 made of an aluminum-based material and seven conductor exposed portions 23 can be inserted therein. The connection terminal 30 is formed, and the connection terminal 30 is made of tough pitch copper having a melting point higher than that of the aluminum conductor 21, and a plurality of conductor exposed portions 23 and connection terminals 30 inserted into the connection terminal 30. By connecting the conductor exposed portion 23 and the connection terminal 30 to each other so that the conductor exposed portion 23 and the connection terminal 30 are connected to each other, the conductor exposed portion 23 and the molten conductor exposed portion 23 are not brought into contact with each other and fixed. And the connection terminal 30 can be connected.

  More specifically, the aluminum-based material has a melting point and a softening point close to each other, and there is a possibility that a part of the aluminum conductor is melted by welding. However, the conductor exposed portion 23 is inserted into the connection terminal 30 formed in an annular cross section. Then, by interposing the connection terminal 30 between the conductor exposed portion 23 and the wire connecting device 40, the conductor exposed portion 23 and the wire connecting device 40 can be connected without contacting the conductor exposed portion 23 and the wire connecting device 40. Can be prevented from sticking.

  In addition, since the connection terminal 30 is made of tough pitch copper having a melting point higher than that of the aluminum conductor 21, the connection terminal 30 is not melted even if the conductor exposed portion 23 is melted. Can be reliably prevented from sticking.

Temporarily, a connection terminal such as an open barrel type that has a non-circular cross-sectional shape may cause the conductor exposed portion 23 to protrude unintentionally from other than the tip end side Xa and the other end side Xb when connected to the conductor exposed portion 23. The connection terminal 30 formed in an annular cross-section can reliably prevent the conductor exposed portion 23 from protruding from other than the tip end side Xa and the other end side Xb when connected to the conductor exposed portion 23.
Therefore, since the conductor exposed portion 23 is securely held inside the connection terminal 30, the conductor exposed portion 23 and the connection terminal 30 can be reliably conducted.

  Furthermore, since the aluminum-based material containing aluminum or an aluminum alloy has a specific gravity smaller than that of a copper-based material containing copper or a copper alloy constituting a conductor of a general covered wire, the covered wire 20 made of an aluminum-based material is used. A plurality of wire harnesses configured by bundling can be efficiently reduced in weight.

  Further, the wire connection structure 10 is configured by performing the crimping welding in which the seven conductor exposed portions 23 and the connection terminals 30 are welded while being crimped, thereby closely contacting the conductor exposed portions 23 and the connection terminals 30. Can be connected.

  More specifically, there is a slight gap between the conductor exposed portion 23 configured as described above and the connection terminal 30 after the wire insertion step, so that the conductor exposed portion 23 is formed on the entire inner surface of the connection terminal 30. There is a possibility that the conductor exposed portion 23 and the connection terminal 30 cannot be connected so that the two are in close contact with each other.

However, since the conductor exposed portion 23 and the connection terminal 30 are welded while being crimped so as to crush the gap between the conductor exposed portion 23 and the connection terminal 30, the wire connection structure 10 includes the conductor exposed portion 23 and the connection terminal 30. It is possible to obtain a connection state in which
Therefore, the conductor exposed portion 23 and the connection terminal 30 can reliably conduct electricity.

  In addition, the wire connection structure 10 includes a connection terminal 30 having a length of 8 mm which is 1/3 to 4/5 of the length of the conductor exposed portion 23 having a length in the longitudinal direction X of 15 mm. On the other hand, the conductivity of the conductor exposed portion 23 and the connection terminal 30 is ensured by arranging the tip of the insulation coating 22 and the other end of the connection terminal 30 in the covered electric wire 20 so as to be separated from each other. Can do.

  Specifically, the seven conductor exposed portions 23 that are compressed by being compressed with the connection terminal 30 are reduced in diameter on the distal end side Xa rather than the other end side Xb in the crimped state with the connection terminal 30. A difference in wire diameter occurs between the conductor exposed portions 23 bundled at the other end side Xb and the conductor exposed portions 23 bundled at the distal end side Xa.

  When the conductor exposed portion 23 and the connection terminal 30 are pressure-bonded so that the tip of the insulation coating 22 and the other end of the connection terminal 30 are in close contact with each other, it is positioned at the boundary between the insulation coating 22 and the connection terminal 30 due to the above-described wire diameter difference. As shown in FIG. 9, the exposed conductor portion 23 is rapidly reduced in diameter. As a result, the conductor exposed portion 23 located at the boundary between the insulating coating 22 and the connection terminal 30 may be disconnected, and a reliable conductive wire between the conductor exposed portions 23 may not be obtained.

  However, the conductor exposed portion located between the insulating coating 22 and the connection terminal 30 by disposing the connection terminal 30 at a position where the tip of the insulation coating 22 and the tip of the connection terminal 30 are separated from the coated electric wire 20. It is possible to prevent the conductor 23 from being rapidly reduced in diameter and to prevent the electrical characteristics from changing or to prevent the conductor exposed portion from being disconnected, and to reliably obtain the conductivity between the conductor exposed portions. .

  In addition, the length of the conductor exposed portion 23 between the tip of the insulating coating 22 and the other end of the connection terminal 30 is equal to or longer than one third of the length of the conductor exposed portion 23. By setting it to 8 mm, it becomes 6 mm in consideration of 1 mm which is the length of the tip exposed portion 24.

  Thus, by ensuring the length of the conductor exposed portion 23 between the tip of the insulation coating 22 and the other end of the connection terminal 30, the tip of the insulation coating 22 is directed toward the other end of the connection terminal 30. Since the conductor exposed portion 23 can be gradually reduced in diameter, it is possible to reduce the change in the electrical characteristics by preventing the conductor exposed portion from being broken while suppressing the change in the electrical characteristics, and to reduce the breakage of the electrical characteristics. For example, the conductor exposed portions 23 can be made to conduct reliably.

  Furthermore, the length of the connection terminal 30 is set to 4/5 or less of the length of the conductor exposed portion 23, so that the connection terminal 30 is connected to the end of the insulation coating 22 and the connection terminal 30 with respect to the coated electric wire 20. Even if the connection terminal 30 is arranged at a position away from the other end, the entire inner surface of the connection terminal 30 and the conductor exposed portion 23 can be connected.

  Moreover, the electric wire connection structure 10 includes the tip exposed portion 24 where the tip of the conductor exposed portion 23 is exposed from the tip of the connection terminal 30 in the connected state of the conductor exposed portion 23 and the connection terminal 30, thereby exposing the conductor. The connection state between the portion 23 and the connection terminal 30 can be maintained.

  More specifically, when the conductor exposed portion 23 and the connection terminal 30 are crimped, the conductor exposed portion 23 in the portion inserted into the connection terminal 30 is reduced in diameter by crimping, but the tip exposed portion 24 exposed from the connection terminal 30 is crimped. However, since the diameter gradually increases toward the distal end side Xa, even if the conductor exposed portion 23 connected to the connection terminal 30 is pulled, the distal end exposed portion 24 that gradually increases in diameter toward the distal end side Xa is provided. The connection state between the conductor exposed portion 23 and the connection terminal 30 can be maintained without being caught by the tip of the connection terminal 30 having a reduced diameter and the conductor exposed portion 23 coming out of the connection terminal 30.

  Further, since the exposed end portion 24 is formed, the exposed conductor portion 23 is reliably connected to the entire inner surface of the connection terminal 30, so that the electrical resistance value between the exposed conductor portions and the connection terminal 30 increases. It is possible to suppress this, and to obtain excellent conductivity.

  Moreover, the electric wire connection structure 10 can improve the deformability of the connection terminal 30 by comprising using the connection terminal 30 comprised with the tough pitch copper whose purity of copper is 60% or more.

  More specifically, a material having a copper purity lower than 60% tends to have a high hardness, and is less deformable than brass or tough pitch copper having a high copper purity. , The connection terminal 30 may be deformed to cause defects such as cracks or cracks in the connection terminal 30.

  However, when the connection terminal 30 is made of tough pitch copper having a purity of copper of 60% or more, the toughness of the connection terminal 30 is improved, and when the conductor exposed portion 23 and the connection terminal 30 are crimped, the connection terminal 30 Therefore, when the conductor exposed portion 23 and the connection terminal 30 are pressure-bonded, it is possible to further suppress the occurrence of defects such as cracks and cracks in the connection terminal 30 due to the deformation of the connection terminal 30. be able to.

  In addition, since the wire connection structure 10 is configured using the connection terminal 30 having a plate thickness of 0.3 mm, the deformability of the connection terminal 30 can be improved and the cost can be reduced. .

Specifically, when the plate thickness of the connection terminal 30 is 2.0 mm or less, more preferably 0.5 mm or less, the connection terminal 30 can be easily deformed when the conductor exposed portion 23 and the connection terminal 30 are pressure-bonded. Therefore, when the connection terminal 30 and the conductor exposed part 23 are pressure-bonded, it is possible to prevent the connection terminal 30 from being damaged due to deformation of the connection terminal 30.
Furthermore, the connection terminal 30 with improved deformability as described above has high shape followability with respect to the conductor exposed portion 23 and can be connected to the conductor exposed portion 23 and the connection terminal 30 in close contact with each other.

  On the other hand, when the plate thickness of the connection terminal 30 is 0.1 mm or more, more preferably 0.3 mm or more, the conductor exposed portion 23 is pulled when the conductor exposed portion 23 is pulled in the connection state between the conductor exposed portion 23 and the connection terminal 30. It is possible to prevent the conductor exposed portion 23 from being pulled out of the connection terminal 30 by force or the connection terminal 30 is damaged, and a stable connection state between the conductor exposed portion 23 and the connection terminal 30 can be obtained.

  Furthermore, as described above, the connection terminal 30 having a plate thickness of 0.1 mm or more and 2.0 mm or less includes a general connection terminal standard, and thus the connection terminal 30 need not be newly designed. The cost can be reduced.

  In addition to making the conductor an aluminum conductor 21 made of an aluminum material, the conductor is made of an aluminum material by reducing the weight of the connection terminal 30 by setting the plate thickness of the connection terminal 30 to 0.3 mm. The entire wire harness can be made lighter than when the aluminum conductor 21 is used.

In addition, in the cross section orthogonal to the longitudinal direction X, the electric wire connection structure 10 is greatly deformed in the width direction Y by crimping the connection terminal 30 while restricting the width direction Y. Since the shape can be prevented from being flat, it is possible to prevent the connection terminal 30 from being cracked or cracked.
Therefore, the conductor exposed portion 23 and the connection terminal 30 can be reliably connected and made conductive.

  Furthermore, when the conductor exposed portion 23 and the connection terminal 30 are not restricted in movement in the width direction Y, the connection terminal 30 is greatly deformed in the width direction Y, and the conductor exposed portion 23 is not intended and extends along the width direction Y. By arranging the conductor exposed portions 23 arranged on both sides in the width direction Y, a load due to bending is applied at the boundary with the insulating coating 22 and the boundary with the connection terminal 30, and the electrical characteristics change as described above. Or there is a risk of disconnection.

  However, by crimping the conductor exposed portion 23 and the connection terminal 30 while restricting movement in the width direction Y, the conductor exposed portion 23 maintains a desired arrangement position without being lined up along the width direction Y. However, since it is connected to the connection terminal 30, the conductor exposed portion 23 and the connection terminal 30 can reliably conduct electricity.

  In addition, the wire connection structure 10 reliably breaks the oxide film formed on the outer periphery of the conductor exposed portion 23 by performing the pressure welding that is welded while being crimped in the wire connecting step. The connection terminal 30 can be electrically connected.

  More specifically, since the aluminum conductor 21 made of an aluminum-based material forms an oxide film on the surface that combines with oxygen in the air to significantly reduce the conductivity, the conductor exposed portion 23 and the connection terminal 30 are reliably connected. May not be able to obtain a good electrical conductivity.

  However, the conductor exposed portion 23 and the connection terminal 30 are connected by welding in the wire connection step, so that the oxide film is surely broken and connected. Obtainable.

Subsequently, an electrical resistance measurement test and a tensile test of the wire connection structure 10 performed as an effect confirmation test of the wire connection structure 10 having the above-described effects will be described.
First, the electrical resistance measurement test refers to a set of aluminum conductors 21 in two covered electric wires 20 out of the eight covered electric wires 20 constituting the electric wire connection structure 10. This is a test for measuring the electrical resistance value.

  Such an electric resistance measurement test was conducted by connecting a connection terminal made of tough pitch copper (copper purity 99.9%, hardness 80 Hv) and the covered electric wire 20 by pressure welding (referred to as specimen A). And a wire connection structure (referred to as specimen B) in which a connection terminal composed of brass (copper purity 70%, hardness 145 Hv) and the covered electric wire 20 were connected by pressure welding.

The specimens A and B were composed of eight covered electric wires 20 having a wire diameter of 0.75 sq and connection terminals having a plate thickness of 0.3 mm and a terminal length of 8 mm.
Among these specimens A and B, specimens A1 and B1, which were crimped and welded to the covered electric wire 20 at a pressure of 0.2 bar, specimens A2 and B2, which were crimped and welded to the coated electric wire 20 at a pressure of 0.4 bar, Specimens A3 and B3 pressure welded to the coated wire 20 at a pressure of 0.6 bar, Specimens A4 and B4 pressure welded to the coated wire 20 at a pressure of 0.8 bar, and a pressure welded to the covered wire 20 at a pressure of 1.0 bar. An electrical resistance measurement test was performed as the specimens A5 and B5.

As a result, as shown in FIG. 6, the specimen A1 bonded by pressure welding with a pressure of 0.2 bar has a variation in the electric resistance value due to the combination between the two aluminum conductors 21, and a combination having a high electric resistance value is obtained. Confirmed that there are many.
On the other hand, it was confirmed that the specimen A5 bonded by pressure bonding with a pressure of 1.0 bar cut the aluminum wire constituting the aluminum conductor 21 by pressure bonding. In addition, cracking did not occur in the connection terminal.

  On the other hand, the specimens A2, A3, and A4, which are pressure-welded with pressures of 0.4 bar, 0.6 bar, and 0.8 bar, do not cause a large variation in the electric resistance value between the aluminum conductors 21 and cracks in the connection terminals. It was confirmed that it had good connection performance.

In addition, as shown in FIG. 7, the specimens B1 and B2 welded by pressure welding at pressures of 0.2 bar and 0.4 bar cause variations in electrical resistance values depending on the combination between the two aluminum conductors 21, and the electrical resistance It was confirmed that there were many combinations with high values.
On the other hand, it was confirmed that the specimen B5, which was crimped and welded at a pressure of 1.0 bar, was cracked in the connection terminal 30 by the crimping.

  On the other hand, specimens B3 and B4 welded by pressure bonding with a pressure of 0.6 bar and 0.8 bar have good connection performance without causing large variations in the electric resistance value between the aluminum conductors 21 and cracking of the connection terminals. It was confirmed that it had.

  Based on the test results, the wire connection structure 10 in which the connection terminal made of tough pitch copper having a copper purity of 99.9% and the covered wire 20 is connected has a lower limit of the applied pressure of 0.4 bar or more, and aluminum. It was confirmed that the upper limit of the applied pressure was 0.8 bar by cutting the aluminum wire constituting the conductor 21.

Similarly, in the wire connection structure 10 in which the connection terminal made of brass having a copper purity of 70% and the covered wire 20 are connected, it can be confirmed that the lower limit value of the applied pressure is 0.6 bar or more. It was confirmed that the upper limit of the applied pressure was 0.8 bar.
In addition, since the tough pitch copper having a copper purity of 99.9% does not generate cracks at the connection terminal 30 at 1.0 bar, it is considered that the pressurizing force that causes cracking decreases as the purity of the copper decreases.

Based on the test results of these electrical resistance measurement tests, in order to obtain good connection performance, the lower the copper purity is, the higher the hardness is, the lower the lower limit value of the applied pressure is, and the connection terminal is not cracked. Therefore, the upper limit value of the pressurizing force tends to decrease as the copper purity is lower and the hardness is higher, and the range of the pressurizing force that can obtain a good connection state as the copper purity is lower and the hardness is higher is gradually It seems to narrow.
Here, since the brass generally used has a copper purity of 60% to 70%, it can be assumed that a good connection state may not be obtained when the purity of copper is lower than 60%. .

Next, the tension test performed in order to confirm the effect of the electric wire connection structure 10 is demonstrated.
Of the eight covered electric wires 20 constituting the electric wire connection structure 10, four randomly selected covered electric wires 20 are pulled from the fixed connection terminal 30 in the opposite direction to the other covered electric wires 20. This is a test for determining whether or not the covered electric wire 20 and the connection terminal 30 constituting the electric wire connection structure 10 can withstand the acting tensile force.

  Such a tensile test was carried out by applying a connecting terminal composed of oxygen-free copper (mechanical properties including hardness are equivalent to tough pitch copper) and eight covered electric wires 20 having a wire diameter of 0.75 sq to a pressure of 0. The test specimen C was connected by pressure welding at 6 bar.

  In addition, the connection terminal which comprises the test body C was formed in internal diameter 3.5mm and terminal length 8mm. Specifically, a specimen C1 configured using a connection terminal having a thickness of 0.1 mm, a specimen C2 configured using a connection terminal having a thickness of 0.2 mm, and a connection terminal having a thickness of 0.3 mm. Tensile tests were performed three times each for the specimen C3 thus constructed, the specimen C4 constructed using a connection terminal having a thickness of 0.4 mm, and the specimen C5 constructed using a connection terminal having a thickness of 0.5 mm. . The result is shown in FIG.

  As shown in FIG. 8, when specimens C1 and C2 configured using connection terminals having thicknesses of 0.1 mm and 0.2 mm are pulled on four randomly selected aluminum conductors 21, an average of about 60 N respectively. It was confirmed that the connection terminal 30 was damaged by a tensile force of 140N.

  On the other hand, when specimens C3, C4, and C5 configured using connection terminals having thicknesses of 0.3 mm, 0.4 mm, and 0.5 mm are pulled on four randomly selected aluminum conductors 21, an average of about It was confirmed that the conductor exposed portion 23 was cut by a tensile force of 175N, 170N, and 185N. The connection terminal was not damaged by the tensile force.

Based on the test result of the tensile test, it was confirmed that the preferable lower limit value of the thickness of the connection terminal was 0.3 mm or more.
On the other hand, since the connection terminal has a tendency to eliminate damage when the plate thickness is 0.3 mm or more, the upper limit cannot be determined by this test, but from the viewpoint of weight reduction and workability of the connection terminal, Since the high pressure increases as the thickness increases, the preferred upper limit value of the thickness of the connection terminal is preferably 0.5 mm.
Therefore, it was possible to evaluate that the preferable thickness range of the connection terminal is 0.3 mm or more and 0.5 mm.

In the above, although the electric wire connection structure 10 in 1st Embodiment was demonstrated, the electric wire connection structure 10a, 10b in 2nd Embodiment and 3rd Embodiment is demonstrated below.
However, among the configurations of the wire connection structures 10a and 10b described below, the same reference numerals are given to the same configurations as those of the wire connection structure 10 in the first embodiment described above, and the description thereof is omitted. .

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.
FIG. 10 shows a longitudinal cross-sectional view of the covered electric wire 20 and the connection terminal 30a before the electric wire insertion step, FIG. 11 (a) shows a vertical cross-sectional view of the wire connection structure 10a, and FIG. The CC sectional view taken on the line in Fig.11 (a) is shown.

As shown in FIG. 10, FIG. 11 (a), and FIG. 11 (b), the electric wire connection structure 10a in the second embodiment includes seven covered electric wires 20 and connection terminals 30a that connect the covered electric wires 20 to each other. The covered electric wire 20 and the connection terminal 30a are connected so as to be conductive. Furthermore, the wire connection structure 10a includes a cap 50 on the distal end side Xa.
In addition, the electric wire connection structure 10a does not necessarily need to include the cap 50.

The connection terminal 30a constituting the wire connection structure 10a has a diameter gradually toward the base end side Xb at the inner edge at the end portion of the base end side Xb, that is, at the inner edge of the insertion opening 31aa into which the conductor exposed portion 23 is inserted. And an enlarged inner edge 32a formed in an arc shape so as to protrude toward the central axis J in a cross section passing through the central axis J of the connection terminal 30a, and further, a distal end portion 31ba of the opened distal end side Xa. A reduced outer edge 33a formed in an arc shape so as to protrude toward the outside of the connection terminal 30a in a cross section passing through the central axis J of the connection terminal 30a while the diameter gradually decreases toward the distal end side Xa. It has.
The enlarged inner edge 32a and the reduced outer edge 33a are formed to have a radius equivalent to the plate thickness of the connection terminal 30a.

  The enlarged inner edge 32a and the reduced outer edge 33a are not limited to being formed in an arc shape. For example, the inner edge of the insertion opening 31aa may be formed in a tapered shape in a cross section passing through the central axis J of the connection terminal 30a. . Further, the enlarged inner edge 32a and the reduced outer edge 33a may be formed at different radii, or may be formed at a radius different from the plate thickness of the connection terminal 30a. Furthermore, the connection terminal 30a is not necessarily provided with the reduced outer edge 33a.

The connection terminal 30a is formed so that the internal cross-sectional area thereof is slightly larger than the total cross-sectional area of the seven conductor exposed portions 23 inserted into the connection terminal 30a.
Specifically, the seven conductor exposed portions 23 to be inserted are arranged in a substantially circular shape, and the total cross-sectional area is 20% or more and 90% or less, more preferably 40% or more of the internal cross-sectional area of the connection terminal 30a. The connection terminal 30a is formed to be about 70%, which is 70% or less.

  Of course, as described above, the cross-sectional area of the connection terminal 30a may be set based on the cross-sectional area of the plurality of conductor exposed portions 23, and the number and wire diameter of the covered electric wires 20 may be set based on the cross-sectional area of the connection terminal 30a. May be set.

  If the enlarged inner edge 31a and the reduced outer edge 32a are provided, the method of forming the connection terminal 30a is not particularly limited. The connection terminal 30a may be configured by removing the unnecessary portion of the plate material, or the enlarged inner edge 31a and the reduced outer edge 32a are formed by bending the distal end side Xa and the proximal end side Xb of the annular plate material. Thus, the connection terminal 30a may be configured.

The cap 50 constituting the electric wire connection structure 10a is made of a synthetic resin having insulating properties, and is formed in a bottomed cylindrical shape in which the distal end side Xa in the longitudinal direction X is closed, and the end portion of the proximal end side Xb To the base end side Xb.
The extended portion 51 can fix the cap 50 and the covered electric wire 20 by, for example, winding a tape or a band.

  The connection terminal 30a and the covered electric wire 20 configured as described above are crimped and welded in the electric wire connection step, and the cap 50 is attached to the distal end side Xa to constitute the electric wire connection structure 10a (see FIG. 11B). . At this time, in the electric wire connection structure 10a, the thickness of the inserted conductor exposed portion 23 at the position of the minimum outer diameter is about one third or more of the thickness of the connection terminal 30a at the position of the minimum outer diameter. 5 minutes.

Then, the effect of the electric wire connection structure 10a in 2nd Embodiment comprised using the above-mentioned connection terminal 30a is demonstrated.
In the electric wire connection structure 10a in the second embodiment, the inner edge of the insertion opening 31aa of the connection terminal 30a is an enlarged inner edge 32a that gradually expands toward the base end side Xb, so that the conductor is exposed inside the connection terminal 30a. The part 23 can be inserted reliably and easily.

More specifically, when the inner edge of the insertion opening 31aa of the connection terminal 30a is an enlarged inner edge 32a that gradually expands toward the base end side Xb, the conductor exposed portion 23 is inserted into the connection terminal 30a. Even if 23 is in contact with the end face of the base end side Xb of the connection terminal 30a, the enlarged inner edge 32a guides the conductor exposed portion 23 to the inside of the connection terminal 30a. Can be inserted easily.
Therefore, the conductor exposed portion 23 and the connection terminal 30a can be reliably conducted.

  Further, the electric wire connection structure 10a forms the enlarged inner edge 32a in an arc shape protruding toward the central axis J in a cross section passing through the central axis J of the connection terminal 30a, and the radius of the arc-shaped enlarged inner edge 32a. By making the plate thickness of the connection terminal 30a equal, it is possible to prevent the covered electric wire 20 from being damaged.

More specifically, in a state where the connection terminal 30a having the arc-shaped enlarged inner edge 32a and the conductor exposed portion 23 are connected, the covered electric wire 20 on the base end side Xb with respect to the connection terminal 30a extends in the radial direction of the connection terminal 30a. Even if it is pulled, the covered electric wire 20 and the connection terminal 30a do not hit each other, so that the covered electric wire 20 can be prevented from being damaged.
Therefore, the conductor exposed portion 23 and the connection terminal 30a can be more reliably conducted.

  In addition, the wire connection structure 10 has a thickness at the position of the minimum outer diameter of the inserted conductor exposed portion 23 that is approximately 6 minutes of the thickness at the position of the minimum outer diameter of the connection terminal 30a in the state of being crimped and welded. Therefore, the aluminum conductor 21 made of an aluminum-based material that has a melting point lower than that of copper generally used for the conductor 21 and is easily melted is melted when the conductor exposed portion 23 and the connection terminal 30a are welded. Since this can be prevented, the conductor exposed portion 23 including the aluminum conductor 21 and the connection terminal 30a can be reliably connected.

  In addition, the electric wire connection structure 10a has a conductor cross-section of the inserted conductor exposed portion 23 of about 70%, which is 90% or less of the cross-sectional area inside the connection terminal 30a. The exposed portion 23 can be inserted more reliably and easily.

  More specifically, since the cross-sectional area of the inserted conductor exposed portion 23 is about 70% of the internal cross-sectional area of the connection terminal 30a, the end of the conductor exposed portion 23 is the outer edge of the insertion opening 31aa in the connection terminal 30a. The conductor exposed portion 23 is prevented from jumping out of the connection terminal 30a or from being scattered inside the connection terminal 30a, so that the conductor exposed portion 23 is more reliably and easily disposed inside the connection terminal 30a. It can insert, and the electroconductivity of the electric wire connection structure 10a can be improved.

  Further, the wire connection structure 10a includes a bottomed cylindrical cap 50 that is mounted so as to surround the connection terminal 30a, and the outer edge of the distal end portion 31ba that is the distal end side Xa of the connection terminal 30a is directed toward the distal end side Xa. In the cross-section passing through the central axis J of the connection terminal 30a, the reduced outer edge 33a protruding toward the outside of the connection terminal 30a can be used to improve the water stoppage of the wire connection structure 10a. In addition, the cap 50 can be easily attached to the wire connection structure 10a.

  More specifically, the wire connection structure 10a includes a bottomed cylindrical cap 50 that is mounted so as to surround the connection terminal 30a, so that moisture enters the connection portion between the conductor exposed portion 23 and the connection terminal 30a. In order to prevent this, the water stoppage of the wire connection structure 10a can be improved.

  Moreover, since the bottomed cylindrical cap 50 can hold, for example, silicon material or the like by injecting it into the inside, it is more reliable that moisture enters the connection portion between the conductor exposed portion 23 and the connection terminal 30a. Therefore, it is possible to further improve the water stoppage of the wire connection structure 10a.

  Furthermore, the electric wire connection structure 10a is formed by gradually reducing the outer edge of the distal end portion 31ba, which is the distal end side Xa of the connection terminal 30a, toward the distal end side Xa, and in the cross section passing through the central axis J of the connection terminal 30a. Since the reduced outer edge 33a protrudes toward the outside of the terminal 30a, the cap 50 can be reliably and easily attached to the connection terminal 30a.

Therefore, the electric wire connection structure 10a in which the cap 50 is attached to the connection terminal 30a to improve the water-stopping property can reliably connect the covered electric wire 20 and the connection terminal 30a.
Furthermore, the electric wire connection structure 10a to which the cap 50 having an insulating property is attached can prevent the connection terminal 30a from coming into contact with other members and conducting electricity unintentionally.

  Instead of the cap 50, for example, a tape or the like may be wound around the outer surface of the connection terminal 30a. Even in this case, the reduced outer edge 33a provided in the connection terminal 30a prevents the tape from hitting the corner of the connection terminal 30a and tearing it, thereby improving the water stoppage of the wire connection structure 10a. it can.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS.
FIG. 12 shows a vertical cross-sectional view of the covered electric wire 20 and the connection terminal 30b before the electric wire insertion step, and FIG. 13 shows a vertical cross-sectional view of the wire connection structure 10b.

  As shown in FIGS. 12 and 13, the wire connection structure 10 b in the third embodiment includes seven covered wires 20 and connection terminals 30 b that connect the covered wires 20 to each other. 20 and the connection terminal 30b are connected so as to be conductive. In addition, the electric wire connection structure 10b of 3rd Embodiment is not provided with the cap 50 unlike the electric wire connection structure 10a of 2nd Embodiment.

  The connection terminal 30b constituting the electric wire connection structure 10b includes an enlarged inner edge 32b at the insertion opening 31ab on the base end side Xb, similarly to the connection terminal 30a constituting the electric wire connection structure 10a of the second embodiment described above. The distal end portion 31bb on the distal end side Xa is provided with a reduced outer edge 33b.

  Furthermore, the connection terminal 30b includes a conductor crimping portion 34 that crimps the conductor exposed portion 23 on the distal end side Xa, and a coating crimping portion 35 that crimps the insulating coating 22 on the proximal end side Xb. Is formed in a stepped shape in which the cross-sectional area is reduced more than the cross-sectional area of the coated crimping portion 35.

Then, the effect of the electric wire connection structure 10b in 3rd Embodiment comprised using the above-mentioned connection terminal 30b is demonstrated.
In the wire connection structure 10b according to the third embodiment, a conductor crimping portion 34 having a cross-section reduced at the connection terminal 30b before crimping is smaller than the coating crimping portion 35 that crimps the conductor exposed portion 23 and the insulation coating 22. As a result, the conductor exposed portion 23 and the connection terminal 30b are connected in close contact with each other without damaging the connection terminal 30b, and the conductivity between the conductor exposed portion 23 and the connection terminal 30b can be ensured. .

  More specifically, since the coated crimping portion 35 to be crimped to the insulating coating 22 coated on the conductor 21 has a larger wire diameter than the conductor crimping portion 34 to be crimped to the conductor exposed portion 23, When the connecting terminal 30b having the same cross section and the coated electric wire 20 are crimped, the conductor crimping portion 34 may be damaged by an increased amount of deformation than the coated crimping portion 35. Is reduced from the cross-section of the coated crimping portion 35 that is crimped to the insulating coating 22, thereby suppressing an increase in the amount of deformation of the conductor crimping portion 34, and preventing the connection terminal 30 b from being damaged. The body 10b can ensure electrical conductivity and water stoppage.

In correspondence between the configuration of the present invention and the above-described embodiment,
The conductor and the aluminum conductor of the present invention correspond to the aluminum conductor 21 of the embodiment,
Similarly,
The connection member and the short connection member correspond to the connection terminal 30,
The welding jig corresponds to the upper mold 41 and the lower mold 42,
The axial direction corresponds to the longitudinal direction X,
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

  For example, the seven covered electric wires 20 are used by bundling the covered electric wires 20 having the aluminum conductors 21. However, if at least one of the covered electric wires 20 has the aluminum conductors 21, the seven covered electric wires 20 are made of copper or a copper alloy. The covered electric wire having the conductor and the covered electric wire 20 having the aluminum conductor 21 may be bundled.

  In addition, the connection terminal 30 is formed in a hollow shape with a circular cross section, but the cross sectional shape is not limited to a circular shape, for example, a rectangle such as a square or a rectangle, as long as it is a circular cross section that allows insertion of a plurality of exposed conductor portions. Or a polygon such as a hexagon or an octagon.

  In addition, the connection terminal 30 is not limited to being composed of tough pitch copper as long as the purity of copper is 60% or more, that is, a material having a hardness of brass or less and a melting point higher than that of an aluminum-based material. You may comprise oxygen-free copper which has a mechanical property equivalent to tough pitch copper, or brass.

  Furthermore, the conductor exposed portion 23 and the connection terminal 30 are not limited to welding by electrical resistance heat as described above, that is, welding by so-called electrical resistance welding, but ultrasonic waves are applied to the welding location to vibrate the welding location. It may be ultrasonic welding in which frictional resistance heat is generated and welded, or laser welding that is welded by irradiating a laser beam to a welding portion.

  In addition, according to the second and third embodiments, the connection terminals 30a and 30b are formed in a cylindrical shape that is open on both the distal end side Xa and the proximal end side Xb, but the connection terminal 30c in other embodiments. As shown in FIGS. 14 (a) and 14 (b) showing the longitudinal sectional views of FIGS. 14 (a) and 14 (d), the connection terminals 30c and 30d may be provided with closed portions 36c and 36d for closing the ends of the distal end side Xa. . In this case, it is possible to reliably prevent the wire connecting device 40 and the conductor exposed portion 23 from coming into contact with each other and improve the water-stopping properties of the wire connecting structures 10c and 10d.

  More specifically, the electric wire connection structures 10c and 10d include the closed portions 36c and 36d on the distal end side Xa of the connection terminals 30c and 30d, so that a part of the molten aluminum conductor 21 is the distal ends of the connection terminals 30c and 30d. The exposed conductors 23 can be connected to each other without melting from the side Xa and coming into contact with the wire connecting device 40, and moisture from the distal end Xa is connected to the connection terminals 30 c and 30 d connected to the exposed conductor 23. Invasion can be reliably prevented, and the water stoppage of the wire connection structures 10c and 10d can be improved.

  Moreover, even if silicon material or the like is injected into the connection terminals 30c and 30d from the insertion openings 31ac and 31ad in order to improve the water-stopping properties of the wire connection structures 10c and 10d, the connection terminals 30c and 30d Since the silicon material or the like can be prevented from flowing down from the distal end side Xa, and the waterproofing property of the proximal end side Xc of the connection terminals 30c and 30d can be secured, the waterproof property of the wire connection structures 10c and 10d is further improved. be able to.

  Further, according to the second embodiment, the connection terminal 30a is provided with the enlarged inner edge 32a and the reduced outer edge 33a in order to insert the conductor exposed portion 23 into the connection terminal 30a reliably and easily. As shown in FIG. 14C, which shows a longitudinal sectional view of the connection terminal 30e, for example, the connection terminal 30e having the same configuration as the connection terminal 30a of the second embodiment has an inner diameter on the base end side Xb that is larger than the outer diameter. An enlarged taper portion 37 may be provided.

In this case, the connection terminal 30e includes the tapered portion 37, and thus has an insertion opening 31ae that is larger than the insertion opening 31aa of the connection terminal 30a in the second embodiment.
In addition, the taper part 37 may be provided not only in the connection terminal 30e which is the same structure as 2nd Embodiment but in the connection terminals 10, 10b, 10c, and 10d mentioned above, for example.

  Thereby, in the electric wire connection structure 10e, in the electric wire insertion process, the taper portion 37 can reliably and easily insert the conductor exposed portion 23 into the connection terminal 30e, and the covered electric wire 20 can be connected. Even if it is pulled in the radial direction of the terminal 30e, the covered electric wire 20 can be more reliably prevented from being damaged.

DESCRIPTION OF SYMBOLS 10, 10a-10e ... Electric wire connection structure 20 ... Covered electric wire 21 ... Aluminum conductor 22 ... Insulation coating 23 ... Conductor exposed part 24 ... End exposed part 30, 30a-30e ... Connection terminal 31aa, 31ab, 31ae ... Insertion opening 31ba, 31bb ... tip end portions 32a and 32b ... enlarged inner edges 33a and 33b ... reduced outer edge 34 ... conductor crimping part 35 ... covering crimping parts 36c and 36d ... blocking part 37 ... taper part 40 ... wire connecting device 41 ... upper mold 42 ... lower mold 43 ... Upper die crimping portion 44 ... Lower die crimping portion 50 ... Cap J ... Center axis X ... Longitudinal direction Xa ... End side Xb ... Other end side Y ... Width direction Z ... Crimping direction

Claims (14)

A cross section in which a conductor is covered with an insulating coating, a plurality of covered electric wires having a conductor exposed portion in which the leading end side of the insulating coating is stripped by a predetermined length to expose the conductor, and a plurality of the conductor exposed portions are inserted therein A connection member formed in an annular shape, and a plurality of the conductor exposed portions are electrically connected so as to be conductive,
The conductor in at least one of the covered electric wires is an aluminum conductor made of an aluminum-based material,
The connecting member is made of a material having a melting point higher than that of the aluminum conductor , and the length of the connecting member in the axial direction is not less than 1/3 and not more than 4/5 of the length of the exposed conductor. A short connection member,
The short connection member is disposed at a position where the distal end of the insulating coating and the proximal end of the short connection member are separated from the covered electric wire,
As a plurality of the conductor exposed portion inserted inside the short-length connecting member and said short-length connecting member, the cross-sectional shape, a substantially oval diameter equivalent to the width of the short-length connecting member before bonding Crimp welded ,
In the welding state of the conductor exposed portion and the short connection member,
The electric wire connection structure in which the tip of the conductor exposed portion is exposed from the tip of the short connection member, and a tip exposed portion that is not reduced in diameter by pressure bonding is formed . The electric wire connection structure according to claim 1, wherein the short connection member is made of a material having a copper purity of 60% or more. A plurality of conductor exposed portions in which the conductor is exposed by peeling a predetermined length of the tip end side of the insulating coating in the coated electric wire with the conductor coated with the insulating coating, are arranged inside the connection member formed in an annular cross section,
The conductor exposed portion and the connection member are welded using a welding jig and connected so as to be conductive.
Using at least one of the covered electric wires having an aluminum conductor in which the conductor is made of an aluminum-based material,
The connecting member is made of a material having a melting point higher than that of the aluminum conductor , and the length of the connecting member in the axial direction is not less than 1/3 and not more than 4/5 of the length of the exposed conductor. A short connection member,
With respect to the covered electric wire, the short connection member is disposed at a position where the distal end of the insulating coating and the proximal end of the short connection member are separated from each other,
A plurality of said exposed conductor portion and said short-length connecting member, in a cross section perpendicular to the axial direction of the short-length connecting member, a direction intersecting the crimping direction for crimping said short elongate connecting member, said short-length connection The member is welded while crimping the short connection member so that the cross-sectional shape is substantially elliptical while regulating the width to be equal to the diameter of the short connection member before crimping ,
In the welding state of the conductor exposed portion and the short connection member,
The wire connecting method, wherein the tip of the conductor exposed portion is exposed from the tip of the short connection member, and a tip exposed portion that is not reduced in diameter by pressure bonding is formed . The electric wire connection method of Claim 3 performed using the said short-shaped connection member comprised with the material whose copper purity is 60% or more.   The plurality of exposed conductor portions inserted into the short connection member are arranged in a substantially circular shape, and the total cross-sectional area is 20% or more and 90% or less of the internal cross-sectional area of the short connection member. Form
The electric wire connection method according to claim 3 or 4. A plurality of covered electric wires having a conductor exposed portion where the conductor is exposed on the tip side, while covering the conductor with an insulating coating,
An electric wire connection structure that is formed in a ring shape in cross section and is connected to a connection member that inserts the plurality of exposed conductors into the inside from an insertion opening on the base end side,
The conductor in at least one of the covered electric wires is an aluminum conductor made of an aluminum-based material,
The connecting member is made of a material having a melting point higher than that of the aluminum conductor,
The inserted conductor exposed portion and the connection member are connected by welding,
The inner edge of the insertion opening of the connecting member is an enlarged inner edge that gradually expands toward the base end side,
The enlarged inner edge is formed in an arc shape projecting toward the central axis in a cross section passing through the central axis of the connecting member,
An electric wire connection structure in which a radius of the arc-shaped enlarged inner edge is one half or more of a plate thickness of the connection member. A bottomed cylindrical cap mounted so as to surround the connection member,
The wire connection structure according to claim 6 , wherein an outer edge of a distal end portion that is the distal end side of the connection member is a reduced outer edge that is gradually reduced toward the distal end side. A plurality of covered electric wires having a conductor exposed portion where the conductor is exposed on the tip side, while covering the conductor with an insulating coating,
An electric wire connection structure that is formed in a ring shape in cross section and is connected to a connection member that inserts the plurality of exposed conductors into the inside from an insertion opening on the base end side,
The conductor in at least one of the covered electric wires is an aluminum conductor made of an aluminum-based material,
The connecting member is made of a material having a melting point higher than that of the aluminum conductor,
The inserted conductor exposed portion and the connection member are connected by welding,
The inner edge of the insertion opening of the connecting member is an enlarged inner edge that gradually expands toward the base end side,
A bottomed cylindrical cap mounted so as to surround the connection member,
The electric wire connection structure which used the outer edge of the front-end | tip part which is the said front end side of the said connection member as the reduced outer edge gradually reduced toward the said front end side. The enlarged inner edge is formed in an arc shape projecting toward the central axis in a cross section passing through the central axis of the connecting member,
The electric wire connection structure according to claim 8 , wherein a radius of the arc-shaped enlarged inner edge is one half or more of a plate thickness of the connection member. The wire connection structure according to any one of claims 6 to 9 , wherein the plurality of conductor exposed portions and the connection member are welded to each other by pressure bonding involving crimping of the conductor exposed portions and the connection member. . The wire connection structure according to claim 10 , wherein, in the connection member before crimping, the portion to be crimped to the conductor exposed portion is a conductor crimping portion having a cross-section reduced compared to the coating crimping portion to crimp the insulating coating. The wire connection structure according to claim 10 or 11 , wherein in the crimped state, the thickness of the inserted conductor exposed portion is set to one third or more of the thickness of the connection member. The wire connection structure according to any one of claims 6 to 12 , wherein a cross-sectional area of the inserted conductor exposed portion is 90% or less of a cross-sectional area inside the connection member. The electric wire connection structure according to any one of claims 6 to 13 , further comprising a closing portion that closes the tip portion that is the tip side of the connection member.

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