JP6928822B2 - Wire with terminal - Google Patents

Description

The present invention relates to an electric wire with a terminal, and more particularly to an open barrel type electric wire with a terminal.

Conventionally, an electric wire with a terminal is roughly classified into a closed barrel type and an open barrel type according to the form of a crimp terminal for crimping a coated electric wire.

A closed barrel type electric wire with a terminal has a crimping portion formed in a cylindrical shape, and the tip of a covered electric wire in which a conductive wire material (hereinafter, this is also referred to as a "core wire" or a "wire") is exposed. After the portion is inserted into the crimping portion, the crimping portion is plastically deformed in the radial direction and crimped.

On the other hand, the open barrel type electric wire with a terminal has a crimp terminal having a U-shaped cross section with the upper side open, and after the tip of the wire whose wire is exposed from the insulating coating is inserted into the crimp terminal. , The crimping pieces of the crimping terminals are bent inward so as to be close to each other, and the wire rod and the covering material of the coated electric wire are crimped, respectively.

In particular, the crimp terminal of an open barrel type electric wire with a terminal has a general configuration in which the wire barrel portion, which is a portion where the wire material exposed from the coating material of the coated electric wire is crimped by a crimping piece, and the coating material are crimped. It has an insulation barrel portion, which is a portion to be crimped by a piece, and a transition portion provided as a transition portion between the wire barrel portion and the insulation barrel portion. The transition portion is a part of the crimp terminal provided when the plate material which is the material of the crimp terminal is punched out to form the wire barrel portion and the insulation barrel portion.

An electric wire with a crimp terminal has been proposed as an example of using a crimp terminal of an open barrel type electric wire with a terminal (see, for example, Patent Document 1). In this electric wire with a crimp terminal, the core wire portion composed of a plurality of strands exposed to the transition portion provided between the wire barrel portion and the insulation barrel portion is sealed with the first insulating resin, and then the first A second insulating resin having a viscosity higher than that of the insulating resin is dropped onto the first insulating resin and cured.

In the electric wire with a crimp terminal disclosed in Patent Document 1, a resin having a viscosity of 500 mPa · s or more is used as the first insulating resin. The reason is that when a low-viscosity resin with a viscosity of 500 mPa · s or less is used, a part of the resin flows to the mating terminal connection portion, causing poor connection with the mating terminal or peeling of the coating material. This is because the thickness of the resin at the time of removal becomes thin and the corrosion resistance is lowered.

Japanese Unexamined Patent Publication No. 2011-238500

However, in the electric wire with a crimp terminal of Patent Document 1, of the bundle of a plurality of strands exposed in the transition portion, the strands existing on the outside can be covered with the resin, but the viscosity of the first insulating resin is high. Since the wettability was not sufficient at 500 mPa · s or more, it was not possible to cover the inner wire surrounded by the outer wire with the resin. Therefore, the electric wire with a crimp terminal of Patent Document 1 does not have sufficient corrosion resistance.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent corrosion of a conductive wire material exposed at a transition portion provided between a conductor crimping portion and a covering crimping portion in an open barrel type terminal. The purpose is to provide an electric wire with a terminal having improved performance.

In order to achieve the above object, in the present invention, the conductive wire rod (3) is coated with the insulating coating material (4), and the wire rod (3) having a predetermined length on the tip side is the coating material (4). The coated electric wire (2) exposed from the above, the conductor crimping portion (11) for crimping the wire rod (3), the coated crimping portion (12) for crimping the covering material (4), and the conductor crimping portion (11). ) And the coating crimping portion (12), each having a transition portion (15) formed so as to expose a part of the coating material (4) and a part of the wire rod (3) to the outside. The wire rod (3) includes a terminal and a food-proof material (40r, 40s) formed so as to cover the wire rod (3) exposed at the transition portion (15), and the wire rod (3) is composed of a plurality of strands (3a). The food-preventing ingredients (40r, 40s) are present on the inner peripheral side of the outer peripheral side wire (3ag) exposed to the outside in the transition portion (15) and the outer peripheral side wire (3ag). It is characterized in that it is formed so as to cover at least a part of the region between the wire (3ai) on the peripheral side and the outside of the wire (3ag) on the outer peripheral side.

In the present invention, the food-proof material (40r, 40s) is a portion of the inner peripheral side strands (3ai) having a spatial connection with the external space where the outer peripheral side strands (3ag) are exposed. It is characterized in that it is formed so as to cover.

In the present invention, the food-proof material (40r, 40s) is in a state in which the strands (3ag) on the outer peripheral side permeate into the gaps between the plurality of strands (3a) having a spatial connection with the exposed external space. It is characterized in that it is formed of.

In the present invention, the food-proof material (40r, 40s) covers the peeled end surface (4a) of the covering material (4) from above so that the height from the surface of the covering material (4) is 0.01 mm or more. It is characterized in that it is formed in.

In the present invention, the food-proof material (40r, 40s) is characterized in that the height of the coating material (4) from the surface is lower than that of the surface of the coating pressure-bonding portion (12).

In the present invention, the surface of the food-proof material (40r, 40s) is harder than the pencil hardness 6B based on the scratch hardness (pencil method) test method specified by JIS K 5600-5-4: 1999. do.

In the present invention, the surface of the food-proof material (40r, 40s) is harder than the pencil hardness of 6B in the first half after being immersed in a sodium hydroxide solution having a pH of 10 for 24 hours.

In the present invention, the food-proof material (40r, 40s) is made of a photocurable resin.

In the present invention, the food-proof material (40r, 40s) is characterized in that the viscosity at an outside air temperature of 20 ° C. is 500 [mPa · s] or less.

In the present invention, the permeation distance (40r, 40s) representing the distance between the plurality of strands (3a) from the front end side to the rear end side of the covering material (4). It is characterized in that L) is 1 mm or more.

According to the electric wire with a terminal of the present invention, the corrosion resistance to the core wire exposed at the transition portion provided between the conductor crimping portion and the covering crimping portion in the open barrel type terminal can be improved as compared with the conventional case.

It is an external perspective view which shows the whole structure of the electric wire with a terminal which concerns on embodiment. It is a vertical cross-sectional view which shows the sealing structure of the resin with respect to the core wire of a transition part in embodiment. In the embodiment, it is a vertical cross-sectional view showing a state of penetration of the resin into the inner core wire and a cross-sectional view corresponding to the AA'cross section of the vertical cross-sectional view. It is a vertical cross-sectional view which shows the state which the resin does not permeate with respect to the inner core wire in embodiment, and the cross-sectional view which corresponds to the AA'cross section of the vertical cross-sectional view. It is a vertical cross-sectional view which shows the coating thickness of the food-proof material (resin) which covers the coating stripping edge in embodiment, and the cross-sectional view corresponding to AA'cross section of the vertical cross-sectional view. It is a vertical cross-sectional view which shows the other structure of the food-proof material (resin) which covers the coating stripping edge in embodiment. It is a chart (T1) which shows the test result of the anticorrosion test according to the coating thickness of the anticorrosive ingredient (resin) in embodiment. It is a figure which provides the explanation of the pencil hardness test method which measures the hardness of the food-proof material in embodiment by the pencil hardness. It is a chart (T2) which shows the test result corresponding to the type of food protection of the pencil hardness test in embodiment. It is a chart (T3) which shows the test result of an Example and a comparative example corresponding to an Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the embodiments described below are merely examples, and various forms can be taken within the scope of the present invention.

<Structure of electric wire with terminal>
FIG. 1 is a schematic perspective view showing an electric wire 1 with a terminal according to the first embodiment. FIG. 1 (A) is an exploded perspective view before the coated electric wire 2 and the terminal 5 are crimp-connected, and FIG. 1 (B) is from the base end side after the coated electric wire 2 and the terminal 5 are crimp-connected. It is a whole perspective view as seen.

In FIG. 1, the extending direction along the axis CL of the covered electric wire 2 is defined as the “X direction”. Further, the crimping side of the terminal 5 with respect to the covered electric wire 2 is defined as "arrow X1 side (rear end side)", and the non-crimping side is defined as "arrow X2 side (tip side)".

The electric wire 1 with a terminal includes a covered electric wire 2 and a terminal 5. The coated electric wire 2 has a conductive wire rod (hereinafter, also referred to as “core wire”) 3 in which a plurality of strands 3a are bundled, and an insulating coating material 4 that covers the core wire 3. ing.

The core wire 3 is a stranded wire obtained by twisting a plurality of strands 3a. The strand 3a is formed of, for example, a metal material made of aluminum or an aluminum alloy.

The covering material 4 is formed of an insulating substance that covers the core wire 3 from the outside. The covering material 4 is made of, for example, an insulating resin containing polyvinyl chloride (PVC) and cross-linked polyethylene. The coating material 4 may be of any type as long as it is an insulating substance that coats the core wire 3 from the outside.

Further, the tip portion of the covering material 4 on the arrow X2 side forms a peeled end surface 4a along a plane orthogonal to the axis CL. The coated electric wire 2 includes an exposed portion 2a in which only the core wire 3 is exposed from the peeled end surface 4a toward the arrow X2 side, and a covering portion 2b which is the remaining portion excluding the exposed portion 2a. The peeled end face 4a is a boundary surface between the exposed portion 2a and the covering portion 2b, and is an end face generated as a result of cutting and peeling the tip end side of the covering material 4 along a plane orthogonal to the axis CL.

The terminal 5 is an open barrel type female crimping terminal, and includes a crimping portion 10 and a connecting portion 13 for crimping the core wire 3 and the covering material 4. The terminal 5 is not limited to the female crimp terminal, and may be a male crimp terminal. Further, the terminal 5 includes a transition portion (transition portion) 14 that mechanically and electrically connects the crimping portion 10 and the connecting portion 13. That is, the terminal 5 has a structure in which the crimping portion 10, the connecting portion 13, and the transition portion 14 are integrated. The terminal 5 is made of a copper alloy strip such as brass whose surface is tin-plated (Sn-plated).

The connecting portion 13 is formed of a hollow square columnar shape, and includes an elastic contact piece 13a that comes into contact with an insertion tab included in a male crimp terminal (not shown) and receives the insertion of the insertion tab.

The crimping portion 10 includes a conductor crimping portion 11 (wire barrel portion) and a covering crimping portion 12 (insulation barrel portion). Further, the crimping portion 10 includes a transition portion (transition portion) 15 having a predetermined length that mechanically and electrically connects the conductor crimping portion 11 and the covering crimping portion 12. In order to distinguish the above-mentioned transition section 14 from the transition section 15, the transition section 14 will be referred to as a front transition section 14 and the transition section 15 will be referred to as a rear transition section 15.

The conductor crimping portion 11 is a portion for crimping the exposed portion 2a (exposed portion of the core wire 3) of the covered electric wire 2. The conductor crimping portion 11 includes crimping pieces 11a and 11b having a shape in which the upper part is opened substantially in a U shape in a cross section orthogonal to the X direction. The crimp pieces 11a and 11b are formed so as to be bent inward so as to face each other when crimping the covered electric wire 2 to the exposed portion 2a. Thus, the exposed portion 2a (core wire 3) of the coated electric wire 2 is crimped to the terminal 5 at the conductor crimping portion 11 by the crimping pieces 11a and 11b (FIG. 1 (B)).

The coated crimping portion 12 is a portion for crimping the coated portion 2b of the coated electric wire 2. The coating crimping portion 12 includes crimping pieces 12a and 12b having a shape in which the upper part is opened substantially in a U shape in a cross section orthogonal to the X direction. The crimping pieces 12a and 12b are formed so as to be bent inward so as to face each other when crimping the coated electric wire 2 to the covering portion 2b. Thus, the coated portion 2b of the coated electric wire 2 is crimped to the terminal 5 at the coated crimping portion 12 by the crimping pieces 12a and 12b (FIG. 1 (B)).

After the conductor crimping portion 11 crimps the covered electric wire 2 to the exposed portion 2a (core wire 3), the tip surface 11f is formed on the arrow X2 side (tip side) of the conductor crimping portion 11, and the arrow X1 side (rear end side). ) Is formed with a rear end surface 11r.

The tip surface 11f is an end face of the conductor crimping portion 11 on the arrow X2 side (tip side) (hereinafter, also referred to as “tip portion”) along a plane orthogonal to the X direction. The rear end surface 11r is an end surface of the conductor crimping portion 11 on the arrow X1 side (rear end side) (hereinafter, also referred to as “rear end portion”), which is substantially along a plane orthogonal to the X direction. be. However, the rear end surface 11r is slightly inclined toward the arrow X2 as a whole due to the crimping force of the conductor crimping portion 11 against the exposed portion 2a of the covered electric wire 2. Incidentally, the rear end portion including the rear end surface 11r of the conductor crimping portion 11 is a so-called "bell mouth".

The rear transition portion 15 (FIG. 1A) is a portion where an upper portion is opened between the rear end surface 11r of the conductor crimping portion 11 and the front end surface 12f of the covering crimping portion 12. The rear transition portion 15 is composed of a crimping piece 11a, 11b of the conductor crimping portion 11 and a concave step portion lower than the crimping pieces 12a, 12b of the covering crimping portion 12. The rear transition portion 15 has edge portions 15a and 15b of side wall portions arranged in parallel with each other along the axis CL, and the end edges 15a and 15b form a step portion of the rear transition portion 15.

After the core wire 3 of the covered electric wire 2 is crimped by the conductor crimping portion 11, the front electric wire opening 14s is formed in the front transition portion 14. The front electric wire opening 14s is a portion surrounded by the front end surface 11f of the conductor crimping portion 11, the rear end surface 13r of the connecting portion 13, and the end edges 14a and 14b of the front transition portion 14.

As shown in FIG. 2, in the front wire opening 14s, the tip surfaces 3m of the plurality of core wires 3 (exposed portions 2a) in the coated wire 2 are exposed from the tip surface 11f of the conductor crimping portion 11.

In the front electric wire opening 14s, the tip surface 3m of the core wire 3 (exposed portion 2a) of the covered electric wire 2 and the crimping pieces 11a and 11b of the conductor crimping portion 11 are formed in a state of being covered with the resin 40f as a food-proof material. ing. The presence of the resin 40f prevents the intrusion of the electrolytic solution and the like from the outside into the core wire 3. Here, as the resin 40f, for example, any one of silicon-based, acrylic-based, urethane-based, polyamide-based, epoxy-based, fluorine-based, polyvinyl butyral-based, phenol-based, polyimide-based, acrylic rubber-based, and the like can be photocurable. A resin material having can be used as a main component.

Further, after the covering portion 2b of the coated electric wire 2 is crimped by the covering crimping portion 12, the rear electric wire opening portion 15s is formed in the rear transition portion 15. The rear electric wire opening 15s is a portion surrounded by the rear end surface 11r of the conductor crimping portion 11, the front end surface 12f of the covering crimping portion 12, and the end edges 15a and 15b of the rear transition portion 15. That is, the rear electric wire opening 15s is formed so as to expose a part of the core wire 3 (exposed portion 2a) and a part of the covering portion 2b (tip portion) with the peeled end surface 4a of the covering material 4 as a boundary. It is an opening part.

In the rear electric wire opening 15s, the core wire 3 (exposed portion 2a) partially exposed from between the rear end surface 11r of the conductor crimping portion 11 and the peeled end surface 4a of the covering portion 2b of the coated electric wire 2 is used as a food-proof material. It is sealed with the resin 40r and the resin 40s. Here, the resin 40r is formed so as to cover the core wire 3 before the resin 40s, and then the resin 40s is formed so as to cover the resin 40r from above.

The resin 40r removes a part of the core wire 3 exposed in the rear electric wire opening 15s from the outside between the rear end surface 11r of the conductor crimping portion 11 in the rear electric wire opening 15s and the peeled end surface 4a of the covering portion 2b. It is formed to cover.

The resin 40r can be composed mainly of a resin material having the same photocurability as the resin 40f. However, the resin 40r has a lower viscosity before curing than the resin 40f, and the viscosity is 500 mPa · s or less at an outside air temperature of 20 ° C. Practically, the viscosity of the resin 40r is preferably about 100 mPa · s based on the permeation distance L corresponding to the wettability. However, the present invention is not limited to this, and the characteristics of the resin 40f and the characteristics of the resin 40r may be the same.

The resin 40f sealed in the front electric wire opening 14s and the resin 40s sealed in the rear electric wire opening 15s have the same characteristics, but the resins 40f and 40s and the resin 40r have different characteristics. There is. However, the present invention is not limited to this, and the characteristics of the resins 40f and 40s and the characteristics of the resin 40r may be the same.

As described above, the resin 40r has a viscosity of about 100 mPa · s, which is lower than the viscosity of the resin used in Reference 1 (500 mPa · s or more) and is excellent in wettability. Therefore, as shown in FIGS. 3A and 3B, the resin 40r enters the gap between the plurality of strands 3a in the core wire 3 by a capillary phenomenon, and is indicated by an arrow from the peeled end surface 4a on the tip end side of the covering portion 2b. It is formed in a state where it has penetrated into the wire 3a by the penetration distance L toward the X1 side (rear end side). The permeation distance L is a distance at which the resin 40r permeates between the strands 3a toward the arrow X1 side (rear end side).

Here, the permeation distance L can be defined according to the theoretical formula of capillaries (Lucas washburn's formula). According to this theoretical formula, it is generally understood that if the viscosity η of the resin 40r is lowered, the permeation distance L becomes longer, and if the viscosity η is increased, the permeation distance L becomes shorter.

By the way, as shown in FIGS. 4A and 4B, in the plurality of strands 3a in the core wire 3, the plurality of strands (8 in this case) on the outer peripheral side exposed in the rear wire opening 15s. (Hereinafter, this is also referred to as "outer peripheral side strand".) 3ag and a plurality of (three in this case) strands existing on the inner peripheral side of the strand 3ag (hereinafter, this is referred to as "inner peripheral side strand". There is a gap between the 3ai and the inner peripheral side strands 3ai. Among these gaps, a closed gap (hereinafter, referred to as "sealed gap") DS having no spatial connection with the space where the resin 40r covering the outer peripheral side of the outer peripheral side wire 3ag exists. There may be a plurality of them inside the outer peripheral side strand 3ag.

Since such a closed gap DS is not spatially connected to the space where the resin 40r exists, even a resin 40r having a low viscosity does not permeate into the closed space DS and remains as a void. However, this is fine. This is because the closed gap DS is a void in which an electrolytic solution or the like from the outside cannot enter.

In other words, the resin 40r is formed in a gap (region) between the outer peripheral side strand 3ag exposed to the outside and the inner peripheral side strand 3ai existing on the inner peripheral side of the outer peripheral side strand 3ag. Of the inner peripheral side strands 3ai, the outer peripheral side strands 3ag are formed so as to cover a portion having a spatial connection with the space (outer space) where the exposed resin 40r exists. Further, the resin 40r is not only a portion having a spatial connection with the external space, but also a plurality of outer peripheral side strands having a spatial connection with the space where the external resin 40r with exposed outer peripheral side strands 3ag exists. It is formed in a state of penetrating into the gap between 3ag and the inner peripheral side strand 3ai.

On the other hand, the resin 40s (see FIG. 2) covers the resin 40r, the peeled end surface 4a of the coating portion 2b, and the surface (outer peripheral surface) of the coating portion 2b from above, and the resin 40s is the crimping piece 12a. It is formed so as to reach the tip surface 12f.

Further, as shown in FIG. 5, the resin 40s has a height from the surface (outer peripheral surface) when the surface (outer peripheral surface) of the covering portion 2b is covered from above, that is, when the covering portion 2b is peeled off. The thickness (hereinafter, also referred to as “coating thickness”) th in the vicinity of the peeled end face 4a is formed to be at least 0.01 mm or more. However, the height of the resin 40s (coating thickness th) is formed lower than the surface of the crimping piece 12a.

By the way, the case where the resin 40s is formed so as to reach the tip surface 12f of the crimping piece 12a has been described, but the present invention is not limited to this, and for example, as shown in FIG. 6, the resin 40s is Although the resin 40r, the peeled end surface 4a of the covering portion 2b, and the outer peripheral surface of the covering portion 2b are covered from above, the resin 40s may not reach the tip surface 12f of the crimping piece 12a.

The resin 40s is used to cover the resin 40r, and can be composed mainly of a resin material having photocurability like the resin 40f. In this case, the viscosity of the resin 40s is 500 mPa · s or less at an outside air temperature of 20 ° C., but is higher than the viscosity γ (100 mPa · s) of the resin 40r, and the resin 40s and the resin 40f have the same viscosity. However, the viscosity of the resin 40s and the viscosity of the resin 40f do not necessarily have to be the same.

<Resin coating procedure>
Subsequently, the procedure for forming the resins 40f, 40r, and 40s used as food-proof materials will be described. As shown in FIG. 2, the core wire 3 (exposed portion 2a) exposed between the rear end surface 11r of the conductor crimping portion 11 and the peeled end surface 4a of the covering portion 2b of the coated electric wire 2 in the rear electric wire opening 15s. A predetermined amount of resin 40r having a viscosity of γ (100 mPa · s) is added dropwise from above.

After that, it waits until a predetermined elapsed time t (s) elapses. During this time, the gap between the outer peripheral side strands 3ag and the inner peripheral side strands 3ai and the gap between the strands 3a having a spatial connection with the space where the resin 40r exists is concerned. The resin 40r permeates. However, at this time, the resin 40r does not penetrate into the closed space DS. After the elapsed time t (s) has elapsed, the resin 40r is cured by irradiating the resin 40r with UV (Ultra Violet) light from the ultraviolet curing device. This is the first food-proof coating on the core wire 3. Here, as the curing treatment of the resin 40r, it is assumed that UV light having an ^{exposure amount of 3000 mj / cm 2 is irradiated at the same position as the dropping position of the resin 40r.}

In this case, the outer peripheral side strand 3ag is directly irradiated with UV light, but the inner peripheral side strand 3ai is not irradiated with UV light, so that the inner peripheral side strand 3ai is transparent to UV light. It is possible to raise and cure. However, the present invention is not limited to this, and the inner peripheral side strand 3ai may be heated and thermoset. In short, if not only the resin 40r covering the outer peripheral side wire 3ag but also the resin 40r penetrating into the gap of the inner peripheral side wire 3ai can be surely cured, the inner peripheral side wire 3ai can be used. On the other hand, a hybrid curing method in which moisture curing or two-component curing is used in combination may be adopted.

At this stage, the height from the surface when the surface (outer peripheral surface) of the covering portion 2b is covered with the resin 40r from above, that is, the coating thickness th in the vicinity of the peeled end surface 4a at the time of peeling of the covering portion 2b is determined. It is not formed to be 0.01 mm or more. Therefore, for example, a predetermined amount of the resin 40s having a viscosity γ (500 mPa · s) or less different from that of the resin 40r is dropped from above the resin 40r formed in the rear electric wire opening 15s, and at the same time, UV light from the ultraviolet curing device is irradiated. This cures the resin 40s. Here, the viscosity γ of the resin 40s is set to a viscosity different from that of the resin 40r, but the same viscosity as that of the resin 40r may be used. The coating thickness th in the vicinity of the peeled end surface 4a at the time of peeling of the coating portion 2b can be adjusted by adjusting the viscosity γ of the resin 40s, the amount of dropping, the irradiation timing of UV light, and the like.

As a result, the height (coating thickness) th of the resin 40s formed in the vicinity of the peeled end surface 4a at the time of peeling of the covering portion 2b from the surface (outer peripheral surface) of the coating portion 2b is formed to be 0.01 mm or more. It will be. This is the second food-proof coating on the core wire 3.

After that, in the front electric wire opening 14s, the resin 40f is dropped so as to cover the tip surface 3m of the core wire 3 (exposed portion 2a) of the covered electric wire 2 and the crimping pieces 11a and 11b of the conductor crimping portion 11, and at the same time, the ultraviolet curing device. The resin 40f is cured by irradiating with UV light from the above. This is the third food-proof coating on the core wire 3. However, the resin 40f can be dropped and cured at the same time as the resin 40s, which is the second food-proof coating.

<Action and effect>
As described above, in the electric wire 1 with terminals, not only the outer peripheral side wire 3ag exposed in the rear electric wire opening 15s but also the periphery of the inner peripheral side wire 3ai inside the wire 1 is covered with the resin 40r. Since it is coated, the anticorrosion property can be remarkably improved as compared with the conventional case.

As a result, for example, when pinholes are formed in the resins 40r and 40s and electrolyzed water or the like infiltrates through the pinholes 40, even if electrolytic corrosion occurs in the outer peripheral side strands 3ag, the inner peripheral side strands 3ai It is possible to prevent the occurrence of electrolytic corrosion and guarantee the function as an electric wire.

Further, the electric wire 1 with a terminal has a viscosity of 500 mPa from above the resin 40r while being easily permeated to the periphery of the inner peripheral side wire 3ai by the resin 40r having a viscosity γ (100 mPa · s) having excellent wet spread. The surface of the coating portion 2b can be covered with a coating thickness th of 0.01 mm or more with the resin 40s of s or less.

As a result, since the electric wire 1 with terminals has a double coating structure made of the resin 40s and the resin 40r, the risk of deterioration of corrosion resistance due to tearing of the food-proof ingredients (resin 40s and resin 40r) can be significantly reduced. can. However, since the coating thickness th of the resin 40s is formed lower than the surface of the crimping piece 12a, there is no interference when inserting the terminal into the connector housing, and the resin 40s protrudes upward from the coating crimping portion 12. It is also possible to prevent the resin 40s from peeling off due to being caught by another member.

The resin 40s is formed so as to cover the surfaces of the resin 40r and the covering portion 2b and reach the tip surface 12f of the crimping piece 12a. In this case, the bonding between the resin 40s and the crimping piece 12a of the terminal 5 made of a copper alloy strip such as brass is stronger than the bonding between the resin 40s and the covering portion 2b made of PVC or the like. The risk of the resin 40s peeling from the surfaces of the resin 40r and the coating portion 2b can be reduced as compared with the structure in which the resin 40s does not reach the tip surface 12f of the crimping piece 12a (see FIG. 6).

<Anti-corrosion test>
In the electric wire 1 with a terminal having such a configuration, for example, an electric wire having a wire size in which the cross-sectional area of the core wire 3 is 0.75 sq is used, and an anticorrosion test (in this case, a salt spray test and a salt spray test) according to the coating thickness th of the resin 40s. The test results after the moist heat test) are shown in Table T1 of FIG.

In the salt spray test, the electric wire 1 with a terminal is inserted into a cavity (not shown) to be inserted into the terminal, the covered electric wire 2 side is arranged so as to face the ceiling, and the terminal 5 side faces the ground, and the cavity floats in the air. The salt spray test was carried out with the device set in the test device as described above. The condition of the salt water spray test was an example in which 5% by mass of salt water was adjusted to 35 ° C., the salt water was atomized and sprayed continuously for 96 hours.

In the moisture resistance test, the sample (electric wire 1 with terminals) after the salt spray test was set in the moisture resistance test tank and the moisture resistance test was performed. The condition of the moisture resistance test is an example of a case where the sample is left continuously for 96 hours in a moisture resistance test tank having a humidity heat of 80 ± 5 ° C. and a relative humidity of 90 to 95% so that falling water droplets do not adhere to the sample. do.

After that, using the so-called four-terminal method, the covering material 4 is peeled off at the connection portion 13 of the terminal 5 to which the core wire 3 is not attached in the electric wire 1 with terminals and on the arrow X1 side (rear end side) of the covering crimping portion 12. The electrical resistance between the exposed core wire 3 and the portion of the core wire 3 was measured. The measurement of electrical resistance by this four-terminal method is performed in advance before the anticorrosion test (salt spray test and moist heat test), and the resistance value of the electrical resistance before the anticorrosion test and the measurement of the electrical resistance after the anticorrosion test are measured. The change from the value was evaluated.

In this case, if the resistance fluctuation value of the electrical resistance is 3.0 mΩ or less, it is evaluated as "pass (○)", and if the resistance value fluctuation exceeds 3.0 mΩ, it is evaluated as "fail (×)". .. Here, "pass" means that the anticorrosion property is maintained, and "failure" means that the anticorrosion property is impaired. As a result, it was found that if the coating thickness th of the resin 40s is 0.01 mm or more, the anticorrosion property of the terminal-attached electric wire 1 is not impaired in the anticorrosion test (salt spray test and moist heat test).

<Pencil hardness test>
In addition, in the electric wire 1 with terminals, the type of food-proof material (resin 40s) is based on the pencil hardness test method specified in JIS K 5600-5-4: 1999 (general paint test method: scratch hardness (pencil method)). The configuration of the pencil hardness test device 50 when measuring the hardness of the corresponding surface is shown in FIG. 8, and the test results are shown in Table T2 of FIG.

The pencil hardness test device 50 includes a main body 51 having wheels 52 and a pencil 53 attached to the main body 51. The main body 51 is a traveling body that holds the pencil 53 so as to maintain a predetermined angle and travels at a predetermined speed via the wheels 52. The pencil 53 has a core portion 53s, and when the main body portion 51 runs while being pressed against the coating surface (surface) of the resin 40s of the electric wire 1 with terminals, the coating surface of the resin 40s is scratched (damaged). It is used to attach.

Table T2 shows the pencil hardness results according to the pencil hardness (6B (soft), 5B, 4B, ..., 4H, 5H, 6H (hard)) of the core portion 53s in which the coating surface of the resin 40s is not damaged. Table T2 also shows the trauma evaluation and the anticorrosion test evaluation at that time. In this case, for example, if the core portion 53s is 5H but there is no damage, it is expressed as “5H”, and if the core portion 53s has a pencil hardness of 6B and there is damage, it is expressed as “6B ×”.

The trauma evaluation for the resin 40s subjected to the pencil hardness test is performed based on the result of visually confirming the trauma of the resin 40s when the following operations are performed in the initial state immediately after coating the resin 40s. Specifically, it is evaluated whether or not the coating surface of the food-proof material (resin 40s) is damaged when the electric wire 1 with a terminal is repeatedly inserted and removed from the connector housing three times. The confirmation is by visual confirmation with a microscope. The result is "○" when there is no trauma, and "×" when there is trauma.

Further, as an evaluation of the anticorrosion test for the resin 40s subjected to the pencil hardness test, the anticorrosion test (salt spray test and moist heat test) as described above was performed on the electric wire 1 with a terminal after coating with the antifood material (resin 40s). Evaluate "pass (○)" or "fail (x)" after going.

In the pencil hardness test apparatus 50, the pencil hardness test was carried out on the terminal-attached electric wire 1 in the initial state as it was, and the state after the terminal-attached electric wire 1 was immersed in a sodium hydroxide solution having a pH of 10 for 24 hours (hereinafter,). , This is also referred to as “the state after immersion in the solution”), and the test results for each type of the resin 40s, which is a food-proof material, were detected separately from the case where the pencil hardness test was carried out.

As a result, when a solvent-type adhesive resin of type A resin 40s (Asec Co., Ltd .: AS-9339) was used for the electric wire 1 with terminals, a pencil hardness test was performed with a pencil whose core 53s had a pencil hardness of 6B. When it was broken, it was found that the coated surface of the resin 40s was damaged in both the initial state and the state after immersion in the solution. In addition, it was found that both the trauma evaluation and the anticorrosion test evaluation were unsuccessful (x).

Further, when the type B resin 40s (Toagosei Co., Ltd .: 911P3), which is an instant adhesive type, is used for the electric wire 1 with terminals, when the pencil hardness test is performed with a pencil whose core portion 53s has a pencil hardness of 6B. It was found that there was no damage in the initial state, but there was damage in the state after immersion in the solution. In addition, it was found that the trauma evaluation passed (○), but the anticorrosion test evaluation failed (×).

Further, when the type C resin 40s (ThreeBond Co., Ltd .: 3006D), which is an ultraviolet curable resin, is used for the electric wire 1 with terminals, when the pencil hardness test is performed with a pencil whose core portion 53s has a pencil hardness of 3B. It was found that there was no damage in the initial state, and when the pencil hardness test was performed with a pencil having a core portion 53s having a pencil hardness of 2B, there was no damage even in the state after immersion in the solution. In addition, it was found that both the trauma evaluation and the anticorrosion test evaluation passed (○).

Further, when a type D resin 40s (Harves Co., Ltd .: Durasurf DS-3230C), which is a water-repellent resin, is used for the electric wire 1 with a terminal, a pencil hardness test is performed with a pencil whose core 53s has a pencil hardness of 6B. When it was broken, it was found that there was no damage in the initial state, and when the pencil hardness test was performed with a pencil whose core portion 53s had a pencil hardness of 3H, there was no damage even in the state after immersion in the solution. In addition, it was found that both the trauma evaluation and the anticorrosion test evaluation passed (○).

Finally, when a type E resin 40s (Ultra Tech International, Inc .: Ultra-Ever Dry), which is a water-repellent resin, is used for the electric wire 1 with a terminal, the core 53s is a pencil with a pencil hardness of 3B and a pencil hardness. When the test was performed, it was found that there was no damage in the initial state, and when the pencil hardness test was performed with a pencil having a core portion 53s having a pencil hardness of 5H, there was no damage even in the state after immersion in the solution. In addition, it was found that both the trauma evaluation and the anticorrosion test evaluation passed (○).

That is, with respect to the resins 40s of types C, D, and E, the surface of the resin 40s was not damaged by the pencil 53 having a pencil hardness of 6B in both the initial state and the state after immersion in the solution. Therefore, it was found that when the resin 40s of the types C, D, and E was used, the pencil hardness of 6B was always satisfied. Therefore, if a resin 40s harder than the pencil hardness 6B is used as a reference for the hardness of the resin 40s, the risk of the resin 40s peeling off from the surfaces of the resin 40r and the coating portion 2b can be reduced.

<Viscosity of food-proof ingredients>
The reason why the viscosity γ of the food-proof material (resin 40r) is set to 500 mPa · s or less at an outside air temperature of 20 ° C. will be described below according to Examples and Comparative Examples. Specifically, the height of 1 mm above the core wire 3 (exposed portion 2a) exposed between the rear end surface 11r of the conductor crimping portion 11 in the electric wire 1 with terminals and the peeled end surface 4a of the covering portion 2b of the coated electric wire 2. Only 5 mg of a resin 40r having a viscosity γ is dropped from the position. Here, the cross-sectional area of the core wire 3 is 0.75 sq. Then, after 1 second has passed, the curing treatment is performed with UV light, and then 1 day (24 hours) later, the permeation distance permeated from the peeled end surface 4a of the covering portion 2b to the inside of the wire 3a to the arrow X1 side (rear end side). L was measured.

In Examples 1 to 3, when the number of samples is n (n = 10), all the test results of the above-mentioned anticorrosion test (salt spray test and moist heat test) are passed (○), partially rejected (Δ), and all. It was evaluated as a failure (x).

In Example 1, when the resin 40r had a viscosity γ (100 mPa · S), the permeation distance L for all the samples was 2 mm or more, and the results of the anticorrosion test (salt spray test and moist heat test) were also passed in all the samples ( ○). Here, the permeation distance L is the result of rounding off the decimal point or less.

In Example 2, when the resin 40r had a viscosity of γ (200 mPa · S), the permeation distance L for all the samples was 1 mm or more, and the results of the anticorrosion test (salt spray test and moist heat test) also passed in all the samples ( ○).

In Example 3, when the resin 40r had a viscosity γ (500 mPa · S), the permeation distance L for all the samples was 1 mm or more, and the results of the anticorrosion test (salt spray test and moist heat test) were also passed in all the samples ( ○).

On the other hand, in Comparative Example 1, the permeation distance L when the resin 40r having a viscosity γ (700 mPa · s) was dropped was 0 mm, and the result of the anticorrosion test was that 8 out of 10 samples were partially unacceptable. It passed (△).

Further, in Comparative Example 2, the permeation distance L when the resin 40r having a viscosity γ (1,100 mPa · s) was dropped was 0 mm, and the result of the anticorrosion test was that 6 out of 10 samples passed or partially failed. It became (△).

Further, in Comparative Example 3, the permeation distance L when the resin 40r having a viscosity γ (10,000 mPa · s) was dropped was 0 mm, and the result of the anticorrosion test was that 0 out of 10 samples passed (all failed). ×).

As described above, it was found that the anticorrosion stability of Comparative Examples 1 to 3 was significantly inferior to that of Examples 1 to 3. However, in Comparative Examples 1 to 3, it is considered possible to improve the anticorrosion stability by increasing the number of coating points of the resin 40r and setting the elapsed time until the curing treatment to be longer than 1 second, but the time. Will be required and productivity will decrease. Therefore, when the viscosity γ of the resin 40r is 500 mPa · s or less as in Examples 1 to 3, the resin 40r can penetrate into the core wire 3 and stable corrosion resistance can be realized.

<Other embodiments>
In the above-described embodiment, the case where the resin 40s is formed on the resin 40r has been described, but the present invention is not limited to this, and the viscosity γ of the resin 40r and the elapsed time until UV curing is performed. Considering t (s), if the resin 40r can be permeated around the inner peripheral side wire 3ai with only the resin 40r and the coating thickness th can be realized, the resin 40s need not be formed.

Further, in the above-described embodiment, the case where the resin 40s having a viscosity of 500 mPa · s or less, which is different from the resin 40r having a viscosity of 100 mPa · s, is used has been described. The viscosity of the resin 40s applied the third time may be 500 mPa · s or more.

1 Wire with terminal 2 Covered wire 3 Wire (core wire)
3a Wire 3ag Outer wire 3ai Inner peripheral wire 5 Terminal 4 Coating material 4a Peeling end face 5 Terminal 10 Crimping part 11 Conductor crimping part 11f Rear end surface 12 Covering crimping part 12f Tip surface 13 Connection part 14 Front transition part 15 Rear Transition part 40f, 40r, 40s Resin 50 Pencil hardness tester 51 Body part 52 Wheel 53 Pencil

Claims (11)

A coated electric wire in which a conductive wire is coated with an insulating coating material and the wire rod having a predetermined length is exposed from the coating material on the tip side.
A part of the covering material and a part of the wire are externally formed between the conductor crimping portion for crimping the wire, the covering crimping portion for crimping the covering material, and the conductor crimping portion and the covering crimping portion. A terminal having a transition portion formed to be exposed,
It is provided with a food-proof material formed so as to cover the wire rod exposed at the transition portion.
The wire is composed of a plurality of strands.
The food-preventing material includes at least a part of the region between the outer peripheral side wire exposed to the outside at the transition portion and the inner peripheral side wire existing on the inner peripheral side of the outer peripheral side wire. It is formed so as to cover the outside of the wire on the outer peripheral side.
The wire rod is sealed with the first resin and the second resin as the food-preventing material, and the second resin is formed so as to cover the first resin.
Terminal with wire distal end of said wire, characterized in that the second resin and the viscosity at ambient temperature 20 ° C. is covered with the third resin is the same. The claim is characterized in that the food-preventing material is formed so as to cover a portion of the inner peripheral side wire having a spatial connection with the exposed external space. The electric wire with a terminal according to 1. Claim 1 or 2 is characterized in that the food-preventing material is formed in a state in which the wires on the outer peripheral side permeate into the gaps between the plurality of wires having a spatial connection with the exposed external space. Wire with terminal described in. Any of claims 1 to 3, wherein the food-preventing material covers the peeled end face of the covering material from above and is formed so that the height from the surface of the covering material is 0.01 mm or more. Electric wire with terminal described in item 1. The electric wire with a terminal according to claim 4, wherein the food-preventing material has a height from the surface of the coating material lower than that of the surface of the coating crimping portion. Any one of claims 1 to 5, wherein the surface of the food-proof material is harder than the pencil hardness 6B based on the scratch hardness (pencil method) test method specified by JIS K 5600-5-4: 1999. Wires with terminals as described in the section. The electric wire with a terminal according to claim 6, wherein the surface of the food-proof material is harder than the pencil hardness 6B after being immersed in a sodium hydroxide solution having a pH of 10 for 24 hours. The electric wire with a terminal according to any one of claims 1 to 7, wherein the food-proof material is made of a photocurable resin. The electric wire with a terminal according to any one of claims 1 to 8, wherein the food-proof material has a viscosity of 500 [mPa · s] or less at an outside air temperature of 20 ° C. 1. The electric wire with terminal described in item 1. The electric wire with a terminal according to any one of claims 1 to 9, wherein the viscosity of the second resin is 500 [mPa · s] or less at an outside air temperature of 20 ° C.

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