Crimp terminal, electric wire with crimp terminal, and medical device sensor

Provided is a crimp terminal including an electric wire connector connectable to an electric wire. The electric wire connector includes a body, a plurality of first crimping pieces extending from a first end of the body, and at least one second crimping piece extending from a second end thereof. The first and second crimping pieces are alternately arranged while being displaced from each other. When the crimping pieces are crimped to connect a core wire of the electric wire, a clearance between one first crimping piece and the second crimping piece formed at a position closest to an insulating member of the electric wire is larger than a clearance between a remaining first crimping piece and the second crimping piece formed at another position. Also provided are an electric wire with the crimp terminal, and a medical device sensor including the electric wire with the crimp terminal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application Nos. 2017-126232 and 2018-032268, filed Jun. 28, 2017, and Feb. 26, 2018, respectively, the disclosures of which are hereby incorporated in their entirety by reference.

FIELD OF THE INVENTION

The present invention relates to a crimp terminal connectable to an electric wire having a core wire made of conductive fibers, an electric wire with the crimp terminal, and a medical device sensor that includes the electric wire with the crimp terminal.

BACKGROUND OF THE INVENTION

A conventionally known crimp terminal includes a plurality of crimping pieces alternately arranged while being displaced from each other in a lengthwise direction to crimp a connected portion of an electric wire (see JP 2010-073346 A). Specifically, the crimp terminal includes, as shown inFIG. 13, a terminal connector101to which a mating terminal or the like is connected, and an electric wire connector102that is continuously formed with the terminal connector101and to which an electric wire is connected (crimped).

The electric wire connector102includes a bottom section1021extending in the same direction as that in which the core wire is arranged (a first direction), a plurality of first side crimping pieces1022extending from a first side edge in a second direction orthogonal to the first direction of the bottom section1021, and a plurality of second side crimping pieces1023extending from a second side edge in the second direction of the bottom section1021. The first side crimping pieces1022and the second side crimping pieces1023are alternately arranged while being displaced from each other in the first direction.

In the crimp terminal100, the core wire exposed in a tip portion of the electric wire is arranged on the bottom section1021, and the first side crimping pieces1022and the second side crimping pieces1023are crimped to embrace the core wire, which causes the core wire to be press-contacted to the bottom section1021(seeFIG. 14). The electric wire is connected to the crimp terminal in this way.

The electric wire connector102of the crimp terminal100configured as above has a larger area of contact between the core wire and the crimping pieces than an electric wire connector in which pairs of crimping pieces1022A and1023A, each of which is arranged at the same position in the first direction, are arranged at intervals in the first direction, as shown inFIG. 15. This configuration sufficiently provides a force to retain the electric wire by the electric wire connector102, or in other words, causes the crimped electric wire to be pulled out of the electric wire connector102when the electric wire is pulled in a pulling direction (i.e. pull-out strength), under the conditions where the crimping pieces are crimped with a reduced force.

Thus, the crimp terminal100can be used for an electric wire having a core wire made of soft metal, such as an aluminum wire, i.e. an electric wire that is likely to be broken with an increased crimping force.

In recent years, there have been some cases where an electric wire having a core wire made not of metal but of conductive fibers such as carbon fibers must be used due to restrictions imposed in certain applications thereof.

When such an electric wire is connected to the crimp terminal, the conductive fibers therein are less likely to be internally stressed at the time of applying pressures. Therefore, in order to obtain a retaining force at a portion to which such an electric wire is connected, crimping must be made with a greater pressing force than the case where the electric wire having the metal core wire that is more likely to be internally stressed is connected. Moreover, for such an electric wire, extremely thin conductive fibers (for example, about several micrometers) are used. Therefore, even if the abovementioned crimp terminal100is used, the conductive fibers are still likely to be broken at the time of crimping the crimping pieces1022,1023; thus, the crimp terminal100connected to the electric wire fails to obtain sufficient pull-out strength.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a crimp terminal capable of securing sufficient pull-out strength when an electric wire having a core wire made of conductive fibers is crimped to an electric wire connector, an electric wire with the crimp terminal, and a medical device sensor that includes the electric wire with the crimp terminal.

The crimp terminal according to the present invention includes: an electric wire connector connectable to an electric wire having a core wire sheathed with an insulating member, the electric wire connector including: a body extending in a first direction that coincides with an extending direction of a portion of the electric wire to which the electric wire connector is connected; a plurality of first crimping pieces extending from a first end in a second direction orthogonal to the first direction of the body; and at least one second crimping piece extending from a second end in the second direction of the body, wherein the plurality of first crimping pieces and the at least one second crimping piece are alternately arranged while being displaced from each other in the first direction, and configured to be crimped to embrace the core wire exposed in a leading end portion of the electric wire so that the core wire is press-contacted to the body, and wherein, when the plurality of first crimping pieces and the at least one second crimping piece are crimped to connect the core wire to the electric wire connector, a first clearance in the first direction between one of the plurality of first crimping pieces and the at least one second crimping piece, the first clearance being formed at a position closest in the first direction to the insulating member of the electric wire, is larger than a second clearance in the first direction between a remaining one of the plurality of first crimping pieces and the at least one second crimping piece, the second clearance being formed at another position in the first direction.

The crimp terminal may be configured such that the first clearance has such a distance that the one of the plurality of first crimping pieces and the at least one second crimping piece having their edges expanding as a result of crimping are not in contact with each other.

The crimp terminal may be configured such that each of the plurality of first crimping pieces has a distal end portion, a proximal end portion, and an edge extending in a direction crossing the second direction between the distal end portion and the proximal end portion of each of the plurality of first crimping pieces, and that the at least one second crimping piece has a distal end portion, a proximal end portion, and an edge extending in a direction crossing the second direction between the distal end portion and the proximal end portion of the at least one second crimping piece.

An electric wire with a crimp terminal according to the present invention includes: any one of the abovementioned crimp terminals; and an electric wire configured to be connected to the electric wire connector of the crimp terminal, wherein the core wire is constituted by conductive fibers.

A medical device sensor according to the present invention includes: a medical sensor body; an output electric wire extending from the medical sensor body; and any one of the abovementioned crimp terminals, wherein the output electric wire is connected to the electric wire connector of the crimp terminal, and the output electric wire has a core wire constituted by conductive fibers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, an embodiment of a crimp terminal according to the present invention will be described with reference toFIG. 1toFIG. 9. The crimp terminal of this embodiment is a connector terminal. More specifically, the crimp terminal is a female connector terminal to which a male connector terminal pin (a mating terminal pin) is connected (fitted). An electric wire having a core wire made of conductive fibers is connectable to the connector terminal.

As shown inFIG. 1toFIG. 4, the connector terminal1includes an electric wire connector2to which an electric wire is connectable. The connector terminal1also includes an electric connector3that is conductive to the electric wire connector2and to which a mating terminal pin P (seeFIG. 8) is detachably connected. The connector terminal1of this embodiment is formed of a conductive metal sheet that is stamped out into a specific shape (seeFIG. 4) and then bent into a tubular shape with an axis parallel to a centerline C1as a central axis C. The connector terminal1is formed of phosphor bronze, but may also be formed of brass, nickel silver, plated stainless steel, or the like. Hereinafter, in a direction of the central axis C, an electric connector3side (the left side inFIG. 3) is referred to as a front side, and an electric wire connector2side (the right side inFIG. 3) is referred to as a rear side.

The electric wire connector2includes a plate-shaped body21, a plurality of conductive crimping pieces22extending from the body21, and at least a pair of sheathed part crimping pieces23extending from a portion of the body21closer to the rear side thereof than the conductive crimping pieces22. In the connector terminal1before it is bent as aforementioned (i.e., it is in the state shown inFIG. 4: hereinafter referred to as “flat plate-shaped connector terminal1”), the conductive crimping pieces22and the sheathed part crimping pieces23are portions extending from both ends in a width direction of the body21(i.e., a direction orthogonal to the centerline C1) toward the outside thereof in the width direction.

The body21is a portion extending in the direction of the central axis C and having a U-shape in a cross section taken in a direction orthogonal to the central axis C.

The plurality of conductive crimping pieces22are crimped to embrace the core wire (a conductor) exposed in a leading end portion of the electric wire so that the core wire is press-contacted to the body21. In the electric wire connector2of the flat plate-shaped connector terminal1(hereinafter referred to simply as “flat plate-shaped electric wire connector2”), as shown inFIG. 5, the plurality of conductive crimping pieces22are constituted by a plurality of first crimping pieces221extending from a first end in the width direction of the body21(i.e., the left end inFIG. 5) and at least one second crimping piece222extending from a second end in the width direction of the same (i.e., the right end inFIG. 5). The plurality of first crimping pieces221and the at least one second crimping piece222alternately extend while being displaced from each other in the direction of the centerline C1(i.e., they are alternately arranged). The electric wire connector2of this embodiment includes two first crimping pieces221and two second crimping pieces222.

Out of the two first crimping pieces221, one (front side) first crimping piece221A has a chevron shape. Specifically, in the flat plate-shaped electric wire connector2, the one first crimping piece221A has a front side edge2214A extending in the width direction of the body21(i.e., a direction orthogonal to the centerline C1) from the first end in the width direction. Also, in the flat plate-shaped electric wire connector2, a rear side edge2215A extends in a direction crossing the width direction of the body21, specifically, in the direction away from the centerline C1as it advances toward the front side, from the first end in the width direction. That is, in the flat plate-shaped electric wire connector2, the front side of the one first crimping piece221A has the edge2214A between a distal end2211A and a proximal end2212A that extends in the width direction, and the rear side of the one first crimping piece221A has the edge2215A between the distal end (distal end portion)2211A and a proximal end (proximal end portion)2213A that extends in the direction crossing the width direction.

Out of the two first crimping pieces221, the other (rear side) first crimping piece221B also has a chevron shape. Specifically, in the flat plate-shaped electric wire connector2, the other first crimping piece221B has a front side edge2214B extending in a direction crossing the width direction of the body21, specifically, in the direction away from the centerline C1as it advances toward the rear side, from the first end in the width direction. Also, in the flat plate-shaped electric wire connector2, a rear side edge2215B extends in the direction crossing the width direction of the body21, specifically, in the direction away from the centerline C1as it advances toward the front side, from the first end in the width direction. That is, in the flat plate-shaped electric wire connector2, the front side of the other first crimping piece221B has the edge2214B between a distal end (distal end portion)2211B and a proximal end (proximal end portion)2212B that extends in the direction crossing the width direction, and the rear side of the other first crimping piece221B has the edge2215B between the distal end (distal end portion)2211B and a proximal end (proximal end portion)2213B that extends in the direction crossing the width direction.

The rear side proximal end2213A of the one first crimping piece221A and the front side proximal end2212B of the other first crimping piece221B coincide with each other in the direction of the centerline C1.

Out of the two second crimping pieces222, one (front side) second crimping piece222A has a chevron shape. Specifically, in the flat plate-shaped electric wire connector2, the one second crimping piece222A has a front side edge2224A extending in a direction crossing the width direction of the body21, specifically, in the direction away from the centerline C1as it advances toward the rear side, from the second end in the width direction. Also, in the flat plate-shaped electric wire connector2, a rear side edge2225A extends in a direction crossing the width direction of the body21, specifically, in the direction away from the centerline C1as it advances toward the front side, from the second end in the width direction. That is, in the flat plate-shaped electric wire connector2, the front side of the one second crimping piece222A has the edge2224A between a distal end (distal end portion)2221A and a proximal end (proximal end portion)2222A that extends in the direction crossing the width direction, and the rear side of the one second crimping piece222A has the edge2225A between the distal end (distal end portion)2221A and a proximal end (proximal end portion)2223A that extends in the direction crossing the width direction.

Out of the two second crimping pieces222, the other (rear side) second crimping piece222B also has a chevron shape. Specifically, in the flat plate-shaped electric wire connector2, the other second crimping piece222B has a front side edge2224B extending in the direction crossing the width direction of the body21, specifically, in the direction away from the centerline C1as it advances toward the rear side, from the second end in the width direction. Also, in the flat plate-shaped electric wire connector2, a rear side edge2225B extends in the width direction of the body21from the second end in the width direction. That is, in the flat plate-shaped electric wire connector2, the front side of the other second crimping piece222B has the edge2224B between a distal end (distal end portion)2221B and a proximal end (proximal end portion)2222B that extends in the direction crossing the width direction, and the rear side of the other second crimping piece222B has the edge2225B between the distal end2221B and a proximal end2223B that extends in the width direction.

The rear side proximal end2223A of the one second crimping piece222A and the front side proximal end2222B of the other second crimping piece222B coincide with each other in the direction of the centerline C1.

As to the crimping pieces221A,221B,222A, and222B of the flat plate-shaped electric wire connector2, a height dimension (a dimension in the width direction) of the other second crimping piece222B from the body21is smaller than the height dimensions of the remaining crimping pieces221A,221B, and222A. Note that the remaining crimping pieces221A,221B, and222A have the same height dimension.

In the flat plate-shaped electric wire connector2, the meeting point between the two first crimping pieces221A and221B (the position at which the proximal end2213A of the one first crimping piece221A coincides with the proximal end2212B of the other first crimping piece221B) and the distal end2221A of the one second crimping piece222A are located at the same position with respect to the direction of the centerline C1. In contrast, the distal end2211B of the other first crimping piece221B and a meeting point between the two second crimping pieces222A and222B (the position at which the proximal end2223A of the one second crimping piece222A coincides with the proximal end2222B of the other second crimping piece222B) are located at different positions with respect to the direction of the centerline C1. Specifically, the distal end2211B of the first crimping piece221B is located closer to the front side than the meeting point between the two second crimping pieces222A and222B.

When the crimping pieces221A,221B,222A, and222B configured as above are crimped so as to embrace a core wire90of an electric wire9, as shown inFIG. 6, a clearance in the direction of the central axis C between the first crimping piece221B and the second crimping piece222B, both of which are formed on the rearmost side (the position close to an insulation sheathed member91of the electric wire9), specifically, the clearance in the direction of the central axis C (a first clearance α), is larger than a clearance between each of the first crimping pieces221A and221B and the second crimping piece222A (the clearance in the direction of the central axis C: a second clearance ß). More specifically, each of the first clearance α and the second clearances ß is a clearance between points (intersections) at which the opposing edges of the adjacent first crimping pieces221A and221B and the adjacent second crimping pieces222A and222B cross a virtual line parallel to the central axis C, the virtual line passing through the crimping pieces221A,221B,222A, and222B in the state of being crimped (seeFIG. 6). In the connector terminal1of this embodiment, the clearance between the other first crimping piece221B and the other second crimping piece222B (the first clearance α) is larger than the clearance between the other first crimping piece221B and the one second crimping piece222A (the second clearance ß) and the clearance between the one first crimping piece221A and the one second crimping piece222A (the second clearance ß).

The first clearance α has such a distance that the first crimping piece221B and the second crimping piece222B having their edges expanding as a result of crimping are not in contact with each other. A more specific description is provided below.

When the crimping pieces221A,221B,222A, and222B are crimped, the edges of the crimping pieces221A,221B,222A, and222B expand compared to their initial state (i.e., the state before they are crimped: see the broken line in the partially enlarged view inFIG. 7), as shown in the cross section inFIG. 7. Further, there are some cases where the crimping pieces221A,221B,222A, and222B after being crimped are slightly displaced, for example, in the direction of the central axis C from estimated positions, depending on the conditions of the core wire90, the electric wire9, and the like at the time of being crimped. The first clearance α is set to such a dimension that the other first crimping piece221B and the other second crimping piece222B are not in contact with each other even if the abovementioned expansion, displacement, or the like occurs. As described above, the other first crimping piece221B and the other second crimping piece222B have such a shape as to form the first clearance α when being crimped. The first clearance α of this embodiment is made to be wider as it advances to the rear side (seeFIG. 6).

Returning toFIG. 1toFIG. 6, the at least a pair of sheathed part crimping pieces23are configured to be crimped to have an insulation sheathed portion of the electric wire9near the exposed core wire90sandwiched between the body21and the at least a pair of sheathed part crimping pieces23. The electric wire connector2of this embodiment includes a pair of sheathed part crimping pieces23. In the flat plate-shaped electric wire connector2, the pair of sheathed part crimping pieces23respectively extend toward the outside in the width direction from portions adjacent to and rearward of the conductive crimping pieces22in the direction of the centerline C1. The sheathed part crimping piece23on a first side in the width direction and the sheathed part crimping piece23on a second side therein are both located at the same position with respect to the direction of the centerline C1.

In the flat plate-shaped connector terminal1that includes the body21, the conductive crimping pieces22, and the sheathed part crimping pieces23, the electric wire connector2is formed with the body21bent to be curved (seeFIG. 1).

The electric connector3includes an electric connector body31continuously provided with the body21, and three or more (three in this embodiment) elastic contact pieces32arranged at intervals around the central axis C. The electric connector3is conductively connected (fitted) to the mating terminal pin P (seeFIG. 8) when the mating terminal pin P is inserted into an area A (seeFIG. 2) surrounded by the three or more elastic contact pieces32.

The electric connector body31includes a tubular portion311surrounding the central axis C, and a stopper piece312extending from the rear end of the tubular portion311toward the central axis C. The electric connector body31also includes terminal side engagement portions313that extend outwardly from the tubular portion311and are engageable with a connector housing in the case where the connector terminal1is housed in the connector housing.

The tubular portion311is a portion inside which a leading end portion of the mating terminal pin P is positioned (i.e. the area surrounded by the tubular portion311) when the mating terminal pin P is fitted to the connector terminal1(seeFIG. 8). The tubular portion311is formed with a rectangular plate portion of the flat plate-shaped connector terminal1having a shape elongated in a direction orthogonal to the centerline C1, the rectangular plate portion being entirely curved into a tubular shape so as to make the central axis C as the center and having the edges in its longitudinal direction of the rectangular plate portion opposed to each other.

The stopper piece312is configured to stop the leading end of the mating terminal pin P from moving further into the inside of the connector terminal1(toward the rear side of the connector terminal1) when the mating terminal pin P is fitted to the connector terminal1. That is, the stopper piece312is configured to abut the leading end of the mating terminal pin P when the mating terminal pin P moving along the central axis C enters the tubular portion311to thereby prevent the leading end of the mating terminal pin P from moving further into the inside of the connector terminal1.

The stopper piece312is formed with a portion extending in the direction of the centerline C1from the rear side end edge of the flat plate-shaped tubular portion311shown inFIG. 4, the portion being bent toward the central axis C in the state where the tubular portion311is in a tubular shape. In the electric connector3of this embodiment, a plurality of stopper pieces312are arranged at intervals in a circumferential direction of the tubular portion311.

The terminal side engagement portions313are portions that engage with a connector housing5(seeFIG. 10) in the case where the connector terminal1is housed in the connector housing5. The terminal side engagement portions313project from the tubular portion311and are inclined with respect to the central axis C so as to be away from the central axis C as they advance toward the rear side.

The three elastic contact pieces32extend along the central axis C, are pressed by the mating terminal pin P when the mating terminal pin P is inserted along the central axis C into the area A surrounded by the elastic contact pieces32, and are thereby elastically deformed. The elastic contact pieces32are arranged at intervals from each other on the circumference of a circle with the central axis C as the center. A specific configuration of each of the elastic contact pieces32is described as follows.

The elastic contact pieces32are elastically-deformable plate-shaped portions that extend from the electric connector body31toward the front side, and are arranged at equal intervals around the central axis C, with their main surfaces (i.e., surfaces orthogonal to a thickness direction thereof)32A directed to the central axis C. Each of the elastic contact pieces32has two bent portions (a first bent portion321and a second bent portion322) arranged at an interval from each other in the direction of the central axis C. Hereinafter, a portion of the elastic contact piece32rearward of the first bent portion321is referred to as a base portion323, a portion thereof between the first bent portion321and the second bent portion322is referred to as a contact portion324, and a portion thereof forward of the second bent portion322is referred to as a leading end portion325.

The base portion323is inclined with respect to the central axis C so as to be away from the central axis C as it advances from the contact portion324toward the rear side (seeFIG. 3).

The contact portion324is a portion that is in contact (conduction) with the mating terminal pin P when the mating terminal pin P is inserted along the central axis C into the area A surrounded by the three elastic contact pieces32(seeFIG. 8). The contact portion324is deflectable. Specifically, the contact portion324extends along the central axis C and is curved in such a direction as to project toward the central axis C. With this curving, an inscribed circle y (seeFIG. 2) that is centered at the central axis C and tangent to a portion of each of the contact portions324closest to the central axis C is made smaller than the outer circumference of the mating terminal pin P. This configuration causes the contact portions324to be pressed in a direction away from the central axis C by the mating terminal pin P that is inserted into the area A surrounded by the elastic contact pieces32.

The leading end portion325extends from a front end of the contact portion324(the edge on the opposite side to the base portion323) and is positioned outward of the contact portion324in a direction orthogonal to the central axis C. Specifically, the leading end portion325is inclined with respect to the central axis C so as to be away from the central axis C as it advances from the contact portion324toward the front side (seeFIG. 3).

The connector terminal1configured as above is used by, for example, being connected to the leading end of the electric wire9having the core wire90made of conductive fibers such as carbon fibers, as shown inFIG. 6. Specifically, the connector terminal1is connected to the electric wire9as follows. Note that in the electric wire9of this embodiment, the core wire90is formed of carbon fibers of several micrometers in diameter that are bundled together.

The electric wire9is connected to the electric wire connector2of the connector terminal1. Specifically, the end portion of the electric wire9with the core wire90exposed is placed on the body21of the electric wire connector2. Subsequently, the conductive crimping pieces22(the first crimping pieces221and the second crimping pieces222) are crimped to embrace the core wire90, which causes the core wire90to be press-contacted to the body21. At this time, crimping is performed so that the rear side (the lower side inFIG. 6) edge of the other second crimping piece222B is not pressed by a crimping jig and thereby not fully laid on (i.e. is slightly raised from) the core wire90side. Then, the sheathed part crimping pieces23are crimped to sandwich the insulated portion of the electric wire9between the sheathed part crimping pieces23and the body21. The connector terminal1is thus connected to the electric wire.

The material of the core wire90of the electric wire9connected to the connector terminal1is not limited to carbon fibers. The core wire90may be of; resin fibers with metal filler; plated fibers such as polyester fibers, carbon fibers, or the like that are metal plated; and conductive fibers such as fibers of polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyanilines, polyacenes, polythiophene vinylenes, and a copolymer of two or more of these polymers. That is, according to the connector terminal1of this embodiment, the electric wire9in the electric wire connector2obtain sufficient pull-out strength even in the case where the core wire90is constituted by bundles of such conductive fibers as carbon fibers that are extremely thin and not internally stressed at the time of crimping. The electric wire connector2can also obtain sufficient pull-out strength even in the case where the core wire90is constituted by other conductive fibers. The connector terminal1is also connectable to an electric wire having a metal core wire.

The connector terminal1may also be used, for example, for medical device sensors or the like. The medical device sensor of this embodiment is, for example, an electrocardiographic electrode10as shown inFIG. 9. The electrocardiographic electrode10includes an electrode body11that is attached to, for example, the skin of a chest of a medical examinee or the like, an output electric wire12extending from the electrode body11, and the connector terminal1connected to a leading end of the output electric wire12. Note that the connector terminal1may be used, for example, while being housed in the connector housing5shown inFIG. 10, or the like.

According to the connector terminal1configured as above, the clearance between the first crimping piece221B and the second crimping piece222B (the first clearance α) that is formed at the position closest in the direction of the central axis C to the insulation sheathed member91of the electric wire9is large when the electric wire9in which the core wire90is constituted by the conductive fibers is connected to the connector terminal1(the electric wire connector2) by crimping the conductive crimping pieces22(the first crimping pieces221and the second crimping pieces222), as shown inFIG. 6. This configuration suppresses the conductive fibers from being broken at the aforementioned portion, thereby obtaining sufficient pull-out strength. A more specific description is provided below.

If the clearance between the first crimping piece221and the second crimping piece222is small when the conductive crimping pieces22are crimped to connect the electric wire9to the connector terminal1, the conductive fibers are likely to be broken between the first crimping piece221and the second crimping piece222(along the boundary therebetween) as a result of, for example, biting of the conductive fibers between the first crimping piece221and the second crimping piece222at the time of crimping. Even if the conductive fibers are broken at another position between the first crimping piece221A or221B and the second crimping piece222A, sufficient pull-out strength of the conductive fibers is obtained by prevention of the conductive fibers from being broken between the other first crimping piece221B and the other second crimping piece222B at the time of crimping. Therefore, sufficient pull-out strength is obtained through the configuration having the first clearance α wider than the second clearance ß (specifically, making the first clearance α wide enough to avoid breaking the conductive fibers due to the biting or the like) to suppress the breakage at the position of the clearance α.

Even if the breakage occurs at a position where any of the second clearances8is formed, sufficient electric conduction is realized between the electric wire9(the core wire90) and the connector terminal1as long as the first crimping pieces221A and221B and the second crimping piece222A are strongly crimped to firmly embrace the core wire90.

In the connector terminal1of this embodiment, the first clearance (the clearance between the other first crimping piece221B and the other second crimping piece222B) a has such a distance that the other first crimping piece221B and the other second crimping piece222B having their edges expanding as a result of crimping are not in contact with each other, in the state where the electric wire9is connected to the connector terminal1(i.e., in the state where the crimping pieces221A,221B,222A, and222B are crimped). Thus, the breakage of the conductive fibers is more reliably suppressed at a position (boundary) between the first crimping piece221B and the second crimping piece222B, the position being located closest in the direction of the central axis C to the insulation sheathed member91of the electric wire9. This consequently secures sufficient pull-out strength more reliably.

In the connector terminal1of this embodiment, for example, each of an edge between the distal end2211B and the proximal end2212B of the first crimping piece221B and an edge between the distal end2221A and the proximal end2222B of the second crimping piece222A extends in a direction crossing the width direction of the body21.

According to such a configuration, in the state where the crimping pieces221B and222A are crimped, the edges of the crimping pieces221B and222A come into contact with the conductive fibers (the conductive fibers constituting the core wire90) so as to cross them diagonally. This configuration increases the area of contact of the crimping pieces with the conductive fibers compared to the case where these edges are in contact with the conductive fibers so as to cross them orthogonally (in the width direction of the body21), which as a result further suppresses the conductive fibers from being broken along the edges.

In the electric wire9to which the connector terminal1configured as above is connected (i.e., the electric wire with the connector terminal), the electric wire9in the electric wire connector2of the connector terminal1obtains sufficient pull-out strength even if the electric wire9having the core wire90constituted by conductive fibers is press-contacted to the electric wire connector2.

That is, in the case where the connector terminal1is used for the medical device sensor10, the electric wire9in the electric wire connector2of the connector terminal1obtains sufficient pull-out strength even if an electric wire having a core wire constituted by conductive fibers is used in the medical device sensor10as an output electric wire.

It is a matter of course that the crimp terminal, the electric wire with the crimp terminal, and the medical device sensor of the present invention are not limited to the aforementioned embodiment, but various modifications can be made without departing from the gist of the present invention. For example, a configuration of an embodiment may be added to a configuration of another embodiment, and part of a configuration of an embodiment may be replaced by a configuration of another embodiment. Further, part of a configuration of an embodiment may be deleted.

In the connector terminal1of the aforementioned embodiment, the conductive crimping pieces22are constituted by the two first crimping pieces221and the two second crimping pieces222, without limitation thereto. The conductive crimping pieces22may be constituted by two or more first crimping pieces221and at least one second crimping piece222. The two or more first crimping pieces221and the at least one second crimping piece222are alternately arranged while being displaced from each other in the direction of the central axis C.

A specific configuration of the electric connector3of the crimp terminal is not limited to the aforementioned embodiment. The electric connector3of the crimp terminal (the connector terminal)1of the aforementioned embodiment is configured to retain the mating terminal pin P using three or more elastic contact pieces32, without limitation thereto. The electric connector3may be configured to be connected to the mating terminal by a fastener member, soldering, or the like.

The connector terminal1may be housed in a connector housing to configure a connector. An example of the configuration of the connector is described as follows.

As shown inFIG. 10toFIG. 12, the connector housing5includes a terminal housing portion6in which the connector terminal1is housed, and a terminal insertion port7through which the mating terminal pin P is inserted. The connector housing5also has a rear end opening8through which the connector terminal1is inserted. A more specific description is provided below. Hereinafter, in the direction of the central axis C, the terminal insertion port7side is referred to as a front side, and the rear end opening8side is referred to as a rear side.

The connector housing5has a tubular shape having the central axis C, and is formed of an insulating resin. The connector housing5has an inner surface50. The inner surface50defines a space (a housing space) S in which the connector terminal1is housed. The terminal housing portion6of this embodiment has the inner surface50and the housing space S. The terminal insertion port7is configured to communicate the housing space S with the outside in the direction of the central axis C at the front end of the connector housing5. The rear end opening8is configured to communicate the housing space S with the outside in the direction of the central axis C at the rear end of the connector housing5.

The inner surface50of this embodiment defines a circular or substantially circular cross section at every position in the direction of the central axis C (cross section in a surface direction orthogonal to the central axis C of the inner surface50). The inner surface50defines a plurality of portions having different diameters. Specifically, the inner surface50has, in order from the front side to the rear side, a first portion51having a smallest diameter, a second portion52having a greater diameter than the first portion51, and a third portion53having a greater diameter than the second portion52(having a greatest diameter). The first portion51and the second portion52are connected to each other through a first reduced diameter portion54that has a diameter reduced as it advances toward the front side. The second portion52and the third portion53are connected to each other through a second reduced diameter portion55that has a diameter reduced as it advances toward the front side. The portions51to55that are defined by the inner surface50share the same central axis.

The first portion51, the first reduced diameter portion54, and the second portion52are configured to enclose the electric connector3through the inner surface50. The second portion52has a housing side engagement portion521configured to engage with the terminal side engagement portions313at a position corresponding to the terminal side engagement portions313of the electric connector3(specifically, the electric connector body31). The housing side engagement portion521of this embodiment is defined by partial reduction of the diameter of the inner surface50, which is provided in the direction of the central axis C, that is, a portion projecting toward the central axis C, and is provided at a position adjacent to (continuous with) the second reduced diameter portion55in the direction of the central axis C. A boundary portion56between the first portion51and the first reduced diameter portion54abuts the base portions323of the elastic contact pieces32from the outside thereof (specifically, the outside in the radial direction of the inner surface50). That is, the boundary portion56supports the base portions323from the outside.

The rear end portion of the third portion53defines the rear end opening8that is formed in the rear end portion of the connector housing5. The housing space S of the connector housing5and the outside space communicate with each other through the rear end opening8.

The connector housing5has a projecting portion70that projects from the first portion51at a certain position in the direction of the central axis C toward the central axis C. The projecting portion70of this embodiment is a wall portion (a front end wall portion) that defines the terminal insertion port7at the front end of the connector housing5. That is, the projecting portion70projects from the end edge on the front end side of the first portion51toward the central axis C. The projecting portion70is provided at a position at which it abuts the leading end portions325of the connector terminal1housed in the connector housing5as a result of the insertion of the mating terminal pin P through the terminal insertion port7into the connector housing5, which causes the contact portions324pressed by the mating terminal pin P to be elastically deformed from a curved form to a flat form. A more specific description is provided below.

In the state before the mating terminal pin P is inserted (the initial state), the contact portions324of the elastic contact pieces32are curved to project toward the central axis C. When the mating terminal pin P is inserted through the terminal insertion port7in the direction of the central axis C in this state, the mating terminal pin P, as it advances toward the rear side, presses the contact portions324of the elastic contact pieces32radially outward of the inner surface50, since the inscribed circle y (seeFIG. 2) is smaller than the outer circumference of the mating terminal pin P. That is, the contact portions324of the elastic contact pieces32are subjected to a pressing force of the mating terminal pin P exerted radially outward of the inner surface50.

At this time, the rear ends of the contact portions324are restricted from moving since they are connected to the base portions323that extend from the electric connector body31engaging with the connector housing5and that are supported by the boundary portion56from the outside in the radial direction of the inner surface50. Thus, the front end edges of the contact portions324subjected to the pressing force move toward the terminal insertion port7, which thereby elastically deforms the contact portions324to make their curvature small. When the mating terminal pin P is fully inserted, the contact portions324are deformed from the curved form to the flat form along the mating terminal pin P.

When the contact portions324are elastically deformed to have the flat form, the leading end portions325are restricted by the first portion51from moving radially outward of the inner surface50, but move toward the front end (the terminal insertion port7side) while being in contact with the first portion51since they are capable of moving along the first portion51. That is, the leading end portions325slide (move while sliding) toward the terminal insertion port7with respect to the first portion51. When the contact portions324are elastically deformed to have the flat form to conform to the mating terminal pin P (seeFIG. 12), the leading end portions325having slid toward the terminal insertion port7with respect to the first portion51abut the projecting portion70. In the state where the contact portions324have been elastically deformed to have the flat form as aforementioned, the entire areas of the contact portions324in the direction of the central axis C are in contact with the mating terminal pin P.

As a result, in the connector (the connector housing5with the connector terminal1housed therein), a sufficient force for retaining the mating terminal pin P is obtained by a retaining force resulting from an elastic restoring force of the elastic contact pieces32(the pressing force applied to the mating terminal pin P) and a frictional force resulting from the contact between the contact portions324and the mating terminal pin P through the entire areas of the contact portions324in the direction of the central axis C, that is, in the insertion direction (force against the mating terminal pin P that is being pulled out). In addition, the connector configured as above requires a smaller elastic restoring force (the pressing force of the elastic contact pieces32applied to the mating terminal pin P) than in the case where a force for retaining the mating terminal pin P is obtained only by the elastic restoring force. This enables ease of inserting the mating terminal pin P into the connector.

That is, while a mating terminal pin is hard to be inserted into a connector that is configured to obtain a force for retaining the mating terminal pin using only the elastic restoring force of elastic contact pieces, the aforementioned connector is configured to obtain the force for retaining the mating terminal pin P using the frictional force in addition to the elastic restoring force, which, as a result, enables both ease of inserting the mating terminal pin P into the connector and obtaining a sufficient force for retaining the mating terminal pin P that has been inserted.

The medical device sensor of the aforementioned embodiment is an electrocardiographic electrode, without limitation thereto. The medical device sensor may be, for example, a blood pressure sensor, an SpO2 (arterial oxygen saturation) sensor, an expiration sensor, and the like.

The connector terminal1is connectable to an electric wire that is used for a variety of devices, not limited to the medical device sensor, and that has a core wire made of conductive fibers.

The crimp terminal, the electric wire with the crimp terminal, and the medical device sensor of this embodiment are as described above, but the present invention is not limited to the aforementioned embodiment, and the design can be appropriately modified within the scope intended by the present invention. The operational advantages of the present invention are also not limited to the foregoing embodiments. That is, the embodiments disclosed herein should be construed in all respects as illustrative but not limiting. The scope of the present invention is not indicated by the foregoing description but by the scope of the claims. Further, the scope of the present invention is intended to include all the modifications equivalent in the sense and the scope of the claims.