Patent Publication Number: US-9887036-B2

Title: Coil end connecting structure

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese patent application No. 2015-077702, filed on Apr. 6, 2015, the disclosure of which is incorporated herein in its entirety by reference. 
     TECHNICAL FIELD 
     The present invention relates to a coil end connecting structure. 
     BACKGROUND ART 
     It is widely performed to form a coil winding using a flat wire. An end of the coil winding is electrically connected to a cable for connecting to another electric instrument via a tubular end connecting member called a sleeve (crimp contact). As a technique of connecting the end connecting member and the end of the flat wire, there is a technical content as disclosed, for example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-319157). In Patent Document 1, the end of the flat wire is deformed into a V-shape and the end in the V-shape is inserted into an inner cylinder part of the sleeve. After the insertion, pressure is applied on the sleeve to crash the sleeve to thereby electrically and mechanically connect the end of the flat wire and the sleeve. 
     SUMMARY OF INVENTION 
     Technical Problem 
     Incidentally, in the case of deforming the end into the V-shape and inserting the end into the inner cylinder part as in Patent Document 1, there is a problem as follows. More specifically, the size of the sleeve is determined depending on required current. At this time, the required size of the sleeve is determined from the dimension of the cable for connecting to another electric instrument. At this time, it is generally advantageous to use a sleeve having a small diameter from among selectable sleeves in terms of costs and space saving and so on. However, there is a limit in bending the end of the flat wire into the V-shape in accordance with the sleeve having the small diameter, and therefore it is inevitable to use a sleeve larger in diameter than the sleeve required in terms of current in order to accommodate the end in the V-shape in the inner cylinder part. 
     On the other hand, the tensile strength of a joint portion is specified by JIS C2085 regarding a sleeve having each size, and the cross-sectional area satisfying the tensile strength is indicated from a crimp contact manufacturer. However, as the diameter of the sleeve increases, the cross-sectional area of a conductor portion required for the inner cylinder part also increases. For this reason, the required cross-sectional area of the conductor portion cannot be satisfied only by folding the end into the V-shape, and at present, another additional conductor portion is sometimes inserted into the inner cylinder part to secure the cross-sectional area. In this case, the need of the other conductor portion accordingly requires not only cost and but also man-hour. 
     The present invention has been made in consideration of the problem, and its object is to provide a coil end connecting structure capable of realizing necessary and sufficient connection without increasing the size of an end connecting member for connecting an end of a flat wire. 
     Solution to Problem 
     To solve the above problem, the present invention is a coil end connecting structure for connecting a coil end extending from a coil winding part formed by winding a flat wire, the coil end connecting structure including: a narrow-width part which is formed by forming a cut part made by cutting out the coil end part on a tip side at least on one side in a width direction thereof; an end connecting member which includes a cylinder body part in a cylindrical shape and in which the narrow-width part is inserted in an inner cylinder part of the cylinder body part; and a crimp part which crimps the cylinder body part to electrically connect the narrow-width part and the end connecting member. 
     Further, in another aspect of the coil end connecting structure of the present invention, it is preferable, in addition to the above invention, that the cut parts are provided on both sides in the width direction of the narrow-width part. 
     Furthermore, in another aspect of the coil end connecting structure of the present invention, it is preferable, in addition to the above invention, that an inner projecting part projecting to an inside of the inner cylinder part is formed at a middle portion in a longitudinal direction of the end connecting member, by denting an outer peripheral surface of the cylinder body part toward the inner cylinder part side, and that the narrow-width part is provided to have a length equal to or smaller than a length of the inner projecting part, and a stepped part of the narrow-width part comes into contact with an end surface of the end connecting member. 
     Furthermore, in another aspect of the coil end connecting structure of the present invention, it is preferable, in addition to the above invention, that between the stepped part and a side surface of the narrow-width part, a curved surface part is provided which smoothly connects the stepped part and the side surface of the narrow-width part. 
     Furthermore, in another aspect of the coil end connecting structure of the present invention, it is preferable, in addition to the above invention, that the narrow-width part is provided with a folded part, and the folded part is folded back toward a root side of the narrow-width part. 
     Advantageous Effects of Invention 
     According to the present invention, a coil end connecting structure becomes capable of realizing necessary and sufficient connection without increasing the size of an end connecting member for connecting an end of a flat wire. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating the entire winding structure having a coil end connecting structure according to one embodiment of the present invention. 
         FIG. 2  is an enlarged plan view illustrating a tip side of a coil end part in the coil end connecting structure in  FIG. 1 . 
         FIG. 3  is a perspective view illustrating the configuration of a sleeve in the coil end connecting structure in  FIG. 1 . 
         FIG. 4  is a front cross-sectional view illustrating a state that the sleeve in the coil end connecting structure in  FIG. 1  is cut at a middle in its longitudinal direction. 
         FIG. 5  relates to a modification example of this embodiment and is a plan view illustrating a configuration in which a narrow-width part is provided so that its axial direction is diagonal with respect to an axial direction of a flat wire. 
         FIG. 6  relates to a modification example of this embodiment and is a plan view illustrating a configuration in which the narrow-width part deviates toward any one side in the width direction. 
         FIG. 7  relates to a modification example of this embodiment and is a plan view illustrating a configuration in which the narrow-width part is slightly wider on its tip side than on its root side. 
         FIG. 8  relates to a modification example of this embodiment and is a plan view illustrating a configuration in which curved surface parts are provided between stepped parts and side surfaces of the narrow-width part; 
         FIG. 9  relates to a modification example of this embodiment and is a plan view for explaining a solving technique when a cross-sectional area of the narrow-width part is insufficient, and is a plan view illustrating a state before a folded part is formed at the narrow-width part. 
         FIG. 10  relates to a modification example of this embodiment and is a plan view illustrating a state after the folded part is formed at the narrow-width part from the state in  FIG. 9 . 
         FIG. 11  is a side view of the configuration in  FIG. 10 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a connecting structure  11  of a coil winding  10  according to one embodiment of the present invention will be described based on the drawings. 
     &lt;Regarding a Winding Structure Having a Coil End Connecting Structure&gt; 
       FIG. 1  is a perspective view illustrating the whole of a winding structure  10  having the coil end connecting structure  11 . As illustrated in  FIG. 1 , the winding structure  10  in this embodiment includes, as main components, a coil winding part  20  and a sleeve  40 . 
     Further, the coil end connecting structure  11  has an end portion extending part  32  extending from the coil winding part  20 , and the sleeve  40  attached to the end portion extending part  32 . Hereinafter, those components will be sequentially described. 
     The coil winding part  20  is formed by winding a flat wire  30 . The flat wire  30  is a conducting wire having a rectangular cross section, and its surface is covered by an insulating coating such as enamel or the like. In  FIG. 1 , the shape of the coil winding part  20  in a plan view is a rounded corner rectangle. However, as the shape of the coil winding part  20 , various shapes such as a circular shape, elliptical shape, rectangular shape and so on in a plan view are employable. 
     Here, as illustrated in  FIG. 1 , from the coil winding part  20 , a coil end part  32  made by extending a part of the flat wire  30  exists. In other words, the coil end part  32  is a portion of the flat wire  30  which does not form the coil winding part  20 . 
       FIG. 2  is an enlarged plan view illustrating a tip side of the coil end part  32 . As illustrated in  FIG. 2 , on the tip side of the coil end part  32 , a narrow-width part  33  is provided. The narrow-width part  33  is formed by providing cut parts  34  made by cutting out the coil end part  32  on both sides in the width direction. More specifically, the narrow-width part  33  is provided such that it is smaller in width dimension than the other portion of the flat wire  30  by an amount corresponding to the existence of the cut parts  34  that are portions made by punching the coil end part  32 . 
     In crimp joining, when the narrow-width part  33  is stuck into the later-described sleeve  40  and a later-described crimp part  44  is further formed, the narrow-width part  33  and the sleeve  40  need to come into mechanical contact with each other without the insulating coating intervening therebetween, and thereby secure electrical conduction between them. Two surfaces of the narrow-width part  33  other than the cut parts  34  are peeled off in advance or after performing the present invention, but provision of the cut parts  34  makes it possible to eliminate the need for the peeling process of the above two surfaces. 
     Note that a portion of the flat wire  30  having a width dimension other than that of the narrow-width part  33  is sometimes called a main wire part  31 . 
     Here, since the existence of the cut parts  34  at the coil end part  32 , stepped parts  35  are provided at the coil end part  32 . The stepped parts  35  are end surface portions of the main wire part  31  facing the cut parts  34 . The stepped parts  35  are configured such that an opening end portion of the sleeve  40  can come into contact therewith. However, when the narrow-width part  33  is long in length, the opening end portion of the sleeve  40  does not, any longer, come into contact with the stepped parts  35 . 
       FIG. 3  is a perspective view illustrating the configuration of the sleeve  40 .  FIG. 4  is a front cross-sectional view illustrating the state that the sleeve  40  is cut at the middle in its longitudinal direction. As illustrated in  FIG. 3  and  FIG. 4 , the sleeve  40  made of metal includes a cylinder body part  41  in a cylindrical shape, and the cylinder body part  41  is provided with an inner cylinder part  42  in a pore shape. Note that the sleeve  40  corresponds to an end connecting member. 
     At a middle portion in the longitudinal direction of the sleeve  40 , an inner projecting part  43  is provided which is made by denting an outer peripheral surface of the cylinder body part  41  toward the inner cylinder part  42  side. The inner projecting part  43  is provided to project to the inside of the inner cylinder part  42 . Therefore, when the narrow-width part  33  is stuck into the inner cylinder part  42  from its opening on one end side and the length of the narrow-width part  33  is longer than the length from the opening on the one end side of the inner cylinder part  42  to the inner projecting part  43 , the inner projecting part  43  prevents the narrow-width part  33  from being further stuck thereinto. 
     Further, in this embodiment, on the outer peripheral surface of the cylinder body part  41 , the crimp part  44  as illustrated in  FIG. 1  is provided. The crimp part  44  is a portion for electrically connecting the narrow-width part  33  and the sleeve  40 , and when the narrow-width part  33  is stuck into the inner cylinder part  42  of the cylinder body part  41  and, in this state, a predetermined region of the cylinder body part  41  closer to the opening on the one end side than the inner projecting part  43  is deformed to be crashed, side surfaces  33   a  of the narrow-width part  33  and the sleeve  40  come into mechanical contact with each other. This makes a state that the electrical conduction is secured between the sleeve  40  and the narrow-width part  33 . 
     Note that from an opening on the other end side of the inner cylinder part  42 , a cable to be connected to a not-illustrated electric instrument is stuck. Besides, the electrical connection to an external electric instrument using a crimp contact may be enabled by sticking the crimp contact into the opening on the other end side of the inner cylinder part  42 . 
     &lt;Regarding a Method of Manufacturing the Coil End Connecting Structure&gt; 
     In the case of forming the above coil end connecting structure  11 , the coil end part  32  of the flat wire  30  is punched on the tip side to form the cut parts  34 . This forms the narrow-width part  33 . Then, the narrow-width part  33  is inserted into the inner cylinder part  42 , and thereafter, the outer peripheral surface of the sleeve  40  in which the narrow-width part  33  is inserted is crashed to form the crimp part  44 . Thus, the coil end connecting structure  11  as illustrated in  FIG. 1  is formed. 
     &lt;Regarding the Dimensional Relationship Between the Sleeve and Narrow-Width Part&gt; 
     In the above-described sleeve  40 , the cross-sectional area of a conductor to be stuck into the inner cylinder part  42  is specified by JIS and the like according to its diameter. For example, it is specified that for a sleeve  40  having a large diameter, a conductor to be stuck into the inner cylinder part  42  needs to have a large cross-sectional area, whereas, conversely, for a sleeve  40  having a small diameter, a conductor to be stuck into the inner cylinder part  42  may have a small cross-sectional area. Under such a limit, it is advantageous in terms of costs and space saving to use a sleeve  40  having a diameter as small as possible as far as the specification of a working current is satisfied to make do with the small cross-sectional area of the conductor. 
     Incidentally, in a conventional configuration, a coil end part is deformed into a V-shape as disclosed in Patent Document 1 and the deformed coil end part is inserted into an inner cylinder part. In this case, there is a limit to deform a flat wire into the V-shape. Therefore, a sleeve larger in diameter than a sleeve having a diameter calculated from the requirements of the working current is to be used. However, with such a sleeve having a larger diameter, the cross-sectional area required by the sleeve having the diameter is not satisfied, and therefore it is necessary to additionally insert another connecting member into the inner cylinder part. 
     The case of bending the coil end part into the V-shape and inserting it into the inner cylinder part of the sleeve as in the conventional configuration, requires labor and costs in bending the coil end part into the V-shape and sticking the other connecting member into the inner cylinder part. 
     In contrast, this embodiment employs a configuration that the narrow-width part  33  having a small width dimension is stuck into the inner cylinder part  42  of the sleeve  40 . The case of sticking the narrow-width part  33  into the inner cylinder part  42  as described above only requires a sleeve  40  having a diameter small by an amount corresponding to the small width dimension of the narrow-width part  33 . 
     Here, the case of bending the coil end part into the V-shape and the case of providing the cut parts  34  on the tip side of the coil end part  32  to form the narrow-width part  33  are compared with each other. Then, for example, in the case of forming the narrow-width part  33 , it is easy to double the aspect ratio by halving the width dimension of the narrow-width part  33  or the like (namely, it is easy to double the ratio of the cross-sectional area of the conductor in the cross-sectional area of the inner cylinder part  42 ). However, in the case of bending into the V-shape, it is not easy to rapidly increase the ratio of the cross-sectional area of the conductor in the cross-sectional area of the inner cylinder part  42 . 
     In contrast to the above, in this embodiment, the diameter of the sleeve  40  decreases, whereas the aspect ratio of the narrow-width part  33  increases, so that the ratio of the narrow-width part  33  being a conductor portion in the cross-sectional area of the inner cylinder part  42  rapidly increases. This eliminates the need to insert, into the inner cylinder part  42 , the additional connecting member which may be necessary when embodying the configuration of Patent Document 1. 
     Note that the narrow-width part  33  is not limited to the configuration illustrated in  FIG. 2 . For example, the narrow-width part  33  may be provided so that its axial direction is diagonal to the axial direction of the flat wire  30  as illustrated in  FIG. 5 . Further, the narrow-width part  33  may deviate toward any one side in the width direction as illustrated in  FIG. 6 , and a configuration in which the cut part  34  does not exist on one side in the width direction may be employed. 
     Further, the narrow-width part  33  may be provided such that it is slightly wider on its tip side than on its root side as illustrated in  FIG. 7 . In this case, the narrow-width part  33  on the tip side can be made to function as a pulling-out preventer when it is stuck into the inner cylinder part  42 . 
     Further, a configuration in which curved surface parts  36  smoothly connecting the stepped parts  35  and the side surfaces  33   a  of the narrow-width part  33  are provided between them as illustrated in  FIG. 8  can also be employed. In the case of providing the curved surface parts  36 , it becomes possible to prevent places where stress concentrates from being formed between the stepped parts  35  and the narrow-width parts  33 . 
     Incidentally, the formation of the cut parts  34  on the tip side of the coil end part  32  may lead to the cross-sectional area of the narrow-width part  33  still insufficient to the diameter of the sleeve  40  in the case where the narrow-width part  33  is formed. In this case, once the cut parts  34  are formed to form the narrow-width part  33 , the aspect ratio increases. Therefore, it becomes difficult to perform processing by bending the coil end part  32  into the V-shape to introduce it into the inner cylinder part  42  or the like. 
     In this case, the problem of the insufficient cross-sectional area can be solved as follows. 
       FIG. 9  is a plan view for explaining a solving technique when the cross-sectional area of the narrow-width part  33  is insufficient, and is a plan view illustrating a state before a folded part  33   b  is formed at the narrow-width part  33 . Further,  FIG. 10  is a plan view illustrating a state after the folded part  33   b  is formed at the narrow-width part  33  from the state in  FIG. 9 .  FIG. 11  is a side view of the configuration of  FIG. 10 . As illustrated in  FIG. 9 , a length L 1  of the narrow-width part  33  is provided to be sufficiently longer than a length L 2  from the opening end portion to the inner projecting part  43  in the inner cylinder part  42 . 
     With respect to the narrow-width part  33  having the length L 1  being the sufficient length, the narrow-width part  33  on the tip side is folded back toward the main wire part  31  to form the folded part  33   b  as illustrated in  FIG. 10  and  FIG. 11 . In other words, on the tip side of the narrow-width part  33 , the folded part  33   b  is provided. In this event, in the narrow-width part  33 , the length from its root to a curved region of the folded part  33   b  being the tip portion in the longitudinal direction is longer than the above-described length L 2 , and the cross-sectional area is secured over the entire length of the inserted part. 
     The folded part  33   b  is inserted into the inner cylinder part  42  in addition to the narrow-width part  33  as described above, whereby the conductor to be stuck into the inner cylinder part  42  is the narrow-width part  33  and the folded part  33   b . This makes it possible to increase the cross-sectional area of the conductor to be stuck into the inner cylinder part  42 , and thereby provide the same effect as that in the case of inserting the additional connecting member in Patent Document 1. 
     &lt;Regarding Effect&gt; 
     According to the coil end connecting structure  11  in the above configuration, the flat wire  30  is cut out at least on one side in its width direction to form the cut part  34  to thereby form the narrow-width part  33 . Then, the narrow-width part  33  is inserted into the inner cylinder part  42  of the sleeve  40 , and thereafter the outer peripheral surface of the sleeve  40  is crashed to form the crimp part  44 . Thus, since the narrow-width part  33  small in width dimension is inserted into the inner cylinder part  42 , the diameter of the sleeve  40  can be small. 
     Further, while the diameter of the sleeve  40  decreases, the aspect ratio of the narrow-width part  33  increases. Therefore, the ratio of the narrow-width part  33  being a conductor portion in the cross-sectional area of the inner cylinder part  42  increases. This eliminates the need to insert, into the inner cylinder part  42 , the additional connecting member which may be necessary in Patent Document 1. 
     Further, it is unnecessary to deform the coil end part  32  into the V-shape and it becomes unnecessary to insert the additional connecting member into the inner cylinder part  42 , unlike the conventional configuration. Therefore, the labor such as bending the coil end part into the V-shape and sticking the additional connecting member into the inner cylinder part can be omitted to reduce the man-hour. 
     Further, the cut parts  34  are provided on both sides in the width direction of the narrow-width part  33  in this embodiment. This can prevent the sleeve  40  from deviating toward any one side in the width direction with respect to the flat wire  30  when the narrow-width part  33  is inserted into the inner cylinder part  42  of the sleeve  40 . 
     Further, in this embodiment, the inner projecting part  43  projecting to the inside of the inner cylinder part  42  is formed at the middle portion in the longitudinal direction of the sleeve  40 , by denting the outer peripheral surface of the cylinder body part  41  toward the inner cylinder part  42  side. Further, the narrow-width part  33  is provided to have a length equal to or smaller than that of the inner projecting part  43 , and the stepped parts  35  of the narrow-width part  33  come into contact with the end surface of the sleeve  40 . Therefore, by bringing the stepped parts  35  into contact with the end surface of the sleeve  40 , the narrow-width part  33  can be accurately positioned with respect to the sleeve  40 . 
     Further, between the stepped parts  35  and the side surfaces  33   a  of the narrow-width part  33 , the curved surface parts  36  smoothly connecting them are provided in this embodiment. Therefore, it is possible to prevent places where stress concentrates from being formed between the stepped parts  35  and the narrow-width parts  33 . 
     Further, the folded part  33   b  is provided at the narrow-width part  33 , and the folded part  33   b  is folded back toward the root side of the narrow-width part  33  in this embodiment. Therefore, even when the cross-sectional area of only the narrow-width part  33  is insufficient with respect to the sleeve  40 , a sufficient cross-sectional area with respect to the sleeve  40  can be secured by inserting also the folded part  33   b  into the inner cylinder part  42 . In other words, the cross-sectional area of the conductor portion can be increased to be double with respect to the inner diameter of the inner cylinder part  42 , thereby making it possible to rapidly increase the required cross-sectional area of the conductor portion. 
     Modification Example 
     One embodiment of the present invention has been described above, and the present invention is variously modified other than the above. Hereinafter, they will be described. 
     In the above-described embodiment, a not-illustrated cable of electric instrument to be stuck into the inner cylinder part  42  from its opening on the other end side is not included as the coil end connecting structure  11 . However, the cable may be included in the concept of the coil end connecting structure  11 . 
     Further, regarding the end connecting member, the case where a sleeve in an entirely cylindrical shape is used is described in the above-described embodiment. However, the end connecting member is not limited to the sleeve in an entirely cylindrical shape. For example, a crimp contact may be used as the end connecting member. 
     Further, the winding structure  10  is not particularly referred to in this embodiment. However, the winding structure  10  may constitute, for example, a reactor, and may be constitute a transformer or the like.