Patent Publication Number: US-11654265-B2

Title: Connection structure and guide wire having the connection structure

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation of application Ser. No. 15/425,149 filed on Feb. 6, 2017, which in turn is a Continuation of PCT/JP2016/077176 filed on Sep. 14, 2016. The disclosure of the prior applications is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     The disclosed embodiments relate to a medical device. Specifically, the disclosed embodiments relate to a connection structure for connecting two metal bodies, and a guide wire having the connection structure. 
     To date, various connection structures for connecting two metal bodies have been proposed, in particular for forming a flexible connected portion. 
     For example, Japanese Patent Application Laid-Open No. 2000-145660 describes a flexible shaft (a connection structure) in which an axial part is connected to a coupling through a bendable part comprising a coiled spring, the coiled spring being a multi-thread coiled spring (see, e.g.,  FIG.  1   ). The coiled spring serves as a connected portion. This enables the connected portion to be flexible. 
     However, the flexible shaft described in Japanese Patent Application Laid-Open No. 2000-145660 has the following disadvantage: the axial part is connected to the coupling through the entire circumference of the coiled spring, and thus the flexible shaft may be somewhat difficult to bend due to the repulsive force of the coiled spring. Further, if the axial part and the coupling comprise dissimilar metals, this dissimilarity needs to be taken into account when a connected portion is formed. 
     Moreover, such a connection structure may potentially be used in a medical device, in particular a guide wire which is used inside a complicatedly winding blood vessel. 
     SUMMARY 
     The disclosed embodiments were derived to address the above problems. An object of the disclosed embodiments is to provide a connection structure for connecting two metal bodies in which the flexibility of a connected portion can be further improved, and in particular an appropriate connection can be provided even when the metal bodies are made of dissimilar metals. 
     In order to achieve the above object, a connection structure between a first metal body formed of a first metal and a second metal body formed of a second metal includes a multi-thread coil formed by winding first element wires comprising the first metal and second element wires comprising the second metal. The multi-thread coil is arranged between the first metal body and the second metal body, and the first metal body is connected to the first element wires of the multi-thread coil, and the second metal body is connected to the second element wires of the multi-thread coil. This can improve the flexibility of a connected portion formed by the multi-thread coil. 
     The first element wires and the second element wires may be adjacently wound one by one, so that the first element wires and the second element wires are alternately disposed. The first element wires are connected to the first body so as to sandwich the second element wires, and the second element wires are connected to the second metal body so as to sandwich the first element wires. This can prevent distortion of the shape of the multi-thread coil as much as possible, and can improve the flexibility of the connected portion. 
     The first metal may be a stainless steel alloy, and the second metal may be a nickel-titanium alloy. The connection structure can improve the flexibility of the connected portion, and can also provide an appropriate connection even though dissimilar metals are used that would otherwise be difficult to directly connect. 
     The connection structure may be used in a guide wire, for example. The guide wire may comprise a core shaft, and a coil body covering a front end of the core shaft. The connection structure connects portions of the core shaft together at a connected portion, thereby improving the flexibility of the connected portion of the core shaft and allowing the guide wire to easily follow a winding blood vessel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a side view of a connection structure according to the disclosed embodiments. 
         FIG.  2    shows a cross-sectional side view of the connection structure shown in  FIG.  1   . 
         FIG.  3    shows a cross-sectional view along line A-A in  FIG.  1   . 
         FIG.  4    shows a cross-sectional view along line B-B in  FIG.  1   . 
         FIG.  5    shows a side view of a connection structure according to the disclosed embodiments. 
         FIG.  6    shows a cross-sectional side view of the connection structure shown in  FIG.  5   . 
         FIG.  7    shows a schematic side view of a guide wire according to the disclosed embodiments. 
         FIG.  8    shows a schematic cross-sectional side view of the guide wire shown in  FIG.  7   . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Below, embodiments of the present invention will be described with reference to the drawings. 
       FIG.  1    shows a side view of a connection structure  1  according to the disclosed embodiments,  FIG.  2    shows a cross-sectional side view of the connection structure  1 ,  FIG.  3    shows a cross-sectional view along line A-A in  FIG.  1   , and  FIG.  4    shows a cross-sectional view along line B-B in  FIG.  1   . 
     Note that in order to clearly indicate that a first rod  3  and first metal element wires  9  as described below comprise the same material, and a second rod  5  and second metal element wires  7  as described below comprise the same material, only portions corresponding to the second rod  5  and the second metal wires  7  are shaded in  FIGS.  1  to  4   . 
     As shown in  FIGS.  1  and  2   , the connection structure  1  connects the first rod  3  comprising a stainless steel alloy and the second rod  5  comprising a nickel-titanium alloy. The connection structure  1  is formed of a multi-thread coil  4  formed by winding the first metal element wires  9  comprising the stainless steel alloy and the second metal element wires  7  comprising the nickel-titanium alloy, and is arranged between the first rod  3  and the second rod  5 . 
     The multi-thread coil  4  in  FIGS.  1  to  4    is formed by winding 6 first metal element wires  9  ( 9   a ,  9   b ,  9   c ,  9   d ,  9   e ,  9   f ) and 6 second metal element wires  7  ( 7   a ,  7   b ,  7   c ,  7   d ,  7   e ,  7   f ). The first metal element wires  9  and the second metal element wires  7  are adjacently wound one by one. 
     As shown in  FIG.  3   , the first rod  3  comprising the stainless steel alloy is welded to the first metal element wires  9  ( 9   a ,  9   b ,  9   c ,  9   d ,  9   e ,  9   f ) comprising the stainless steel alloy, but is not welded to the second metal element wires  7  ( 7   a ,  7   b ,  7   c ,  7   d ,  7   e ,  7   f ) comprising the nickel-titanium alloy. 
     Further, with reference to  FIG.  3   , the first metal element wires  9  ( 9   a ,  9   b ,  9   c ,  9   d ,  9   e ,  9   f ) are welded to the first rod  3  so as to sandwich the second metal element wires  7  ( 7   a ,  7   b ,  7   c ,  7   d ,  7   e ,  7   f ) from both sides of each second metal element wire  7  at a connected portion between the first rod  3  and the multi-thread coil  4 . That is, each second metal element wire  7  is contacted on both sides by first metal element wires  9 . 
     On the other hand, the second rod  5  comprising the nickel-titanium alloy is welded to the second metal element wires  7  ( 7   a ,  7   b ,  7   c ,  7   d ,  7   e ,  7   f ) comprising the nickel titanium alloy, but is not welded to the first metal element wires  9  ( 9   a ,  9   b ,  9   c ,  9   d ,  9   e ,  9   f ) comprising the stainless steel alloy, as shown in  FIG.  4   . 
     Moreover, with reference to  FIG.  4   , the second metal element wires  7  ( 7   a ,  7   b ,  7   c ,  7   d ,  7   e ,  7   f ) are welded to the second rod  5  so as to sandwich the first metal element wires  9  ( 9   a ,  9   b ,  9   c ,  9   d ,  9   e ,  9   f ) from both sides of each first metal element wire  9  at a connected portion between the second rod  5  and the multi-thread coil  4 . 
     Note that the multi-thread coil  4  in  FIGS.  1  to  4    is formed by winding a total of 12 metal element wires (6 first metal element wires  9  and 6 second metal element wires  7 ), but the multi-thread coil  4  is not limited to this configuration. The multi-thread coil  4  can contain any number of the first metal element wires  9  and the second metal element wires  7  as long as the total number of each of the first metal element wires  9  and the second metal element wires  7  is 2 or more. However, the first metal element wires  9  and the second metal element wires  7  preferably cover the entire cross-sectional circumferences of the first rod  3  and the second rod  5  where connected. 
     Further, in the connection structure  1  described above, the first rod  3  comprises a stainless steel alloy, and the second rod  5  comprises a nickel-titanium alloy, and the multi-thread coil  4  is formed by winding the first metal element wires  9  comprising the stainless steel alloy and the second metal element wires  7  comprising the nickel-titanium alloy. However, the configuration is not limited to this. 
     For example, the first rod  3  may comprise a cobalt-chromium alloy, and the second rod  5  may comprise a nickel-titanium alloy, and the multi-thread coil  4  may be formed by winding the first metal element wires  9  comprising the cobalt-chromium alloy and the second metal element wires  7  comprising the nickel-titanium alloy. Alternatively, the first rod  3  may comprise a stainless steel alloy, and the second rod  5  may comprise a cobalt-chromium alloy, and the multi-thread coil  4  may be formed by winding the first metal element wires  9  comprising the stainless steel alloy and the second metal element wires  7  comprising the cobalt-chromium alloy. 
     In the connection structure  1  shown in  FIGS.  1  to  4   , the multi-thread coil  4  formed by winding the first element wires  9  comprising the first metal and the second element wires  7  comprising the second metal is arranged between the first rod  3  comprising the first metal such as a stainless steel alloy and the second rod  5  comprising the second metal such as a nickel-titanium alloy. Additionally, the first rod  3  is not connected to the second metal element wires  7  of the multi-thread coil  4 , but is connected to the first metal element wires  9  of the multi-thread coil  4 , and the second rod  5  is not connected to the first metal element wires  9  of the multi-thread coil  4 , but is connected to the second metal element wires  7  of the multi-thread coil  4 . This can improve the flexibility of the connected portion formed by the multi-thread coil. 
     Further, in the connection structure  1  according to  FIGS.  1  to  4   , the multi-thread coil  4  comprises the first metal element wires  9  and the second metal element wires  7  adjacently wound one by one, and the first metal element wires  9  are connected to the first rod  3  so as to sandwich the second metal element wires  7 , and the second metal element wires  7  are connected to the second rod  5  so as to sandwich the first metal element wires  9 . This can prevent distortion of the shape of the multi-thread coil  4  as much as possible, and can improve the flexibility of the connected portion  1 . 
     Moreover, the connection structure  1  can improve the flexibility of the connected portion, and can also provide an appropriate connection even when dissimilar metals are used such as a stainless steel alloy and a nickel titanium alloy, which are difficult to directly connect to each other. 
       FIG.  5    shows a side view of a connection structure  21  according to the disclosed embodiments, and  FIG.  6    shows a cross-sectional side view of the connection structure  21 . 
     Note that in order to clearly indicate that a third rod  23  and third metal element wires  29  as described below comprise the same material, and a fourth rod  25  and fourth metal element wires  27  as described below comprise the same material, only portions corresponding to the fourth rod  25  and the fourth metal wires  27  are shaded in  FIGS.  5  and  6   . 
     As shown in  FIGS.  5  and  6   , the connection structure  21  connects the third rod  23  comprising a stainless steel alloy to the fourth rod  25  comprising a nickel-titanium alloy. The connection structure  21  is formed of a multi-thread coil  24  formed by winding the third metal element wires  29  comprising the stainless alloy and the fourth metal element wires  27  comprising the nickel-titanium alloy, and is arranged between the third rod  23  and the fourth rod  25 . 
     The multi-thread coil  24  in  FIGS.  5  and  6    is formed by winding 6 third metal element wires  29  ( 29   a ,  29   b ,  29   c ,  29   d ,  29   e ,  29   f ) and  6  fourth metal element wires  27  ( 27   a ,  27   b ,  27   c ,  27   d ,  27   e ,  27   f ). Unlike the multi-thread coil  4 , the multi-thread coil  24  comprises the third metal element wires  29  and the fourth metal element wires  27  adjacently wound two at a time. 
     The third rod  23  comprising the stainless steel alloy is welded to the third metal element wires  29  ( 29   a ,  29   b ,  29   c ,  29   d ,  29   e ,  29   f ) comprising the stainless steel alloy, but is not welded to the fourth metal element wires  27  ( 27   a ,  27   b ,  27   c ,  27   d ,  27   e ,  27   f ) comprising the nickel titanium alloy, as in the multi-thread coil  4 . 
     Further, the third metal element wires  29  ( 29   a ,  29   b ,  29   c ,  29   d ,  29   e ,  29   f ) are welded to the third rod  23  so as to sandwich two of the fourth metal element wires  27  ( 27   a ,  27   b ,  27   c ,  27   d ,  27   e ,  27   f ) from both sides of the pair of fourth metal element wires  27  at a connected portion between the third rod  23  and the multi-thread coil  24 . 
     On the other hand, the fourth rod  25  comprising the nickel-titanium alloy is welded to the fourth metal element wires  27  ( 27   a ,  27   b ,  27   c ,  27   d ,  27   e ,  27   f ) comprising the nickel titanium alloy, but is not welded to the third metal element wires  29  ( 29   a ,  29   b ,  29   c ,  29   d ,  29   e ,  29   f ) comprising the stainless steel alloy, as in the multi-thread coil  4 . 
     Further, the fourth metal element wires  27  ( 27   a ,  27   b ,  27   c ,  27   d ,  27   e ,  27   f ) are welded to the fourth rod  25  so as to sandwich two of the third metal element wires  29  ( 29   a ,  29   b ,  29   c ,  29   d ,  29   e ,  29   f ) from both sides of the pair of third metal element wires  29  at a connected portion between the fourth rod  25  and the multi-thread coil  24 . 
     Note that in the multi-thread coil  24 , two of the third metal element wires  29  ( 29   a ,  29   b ,  29   c ,  29   d ,  29   e ,  29   f ) are paired, and two of the fourth metal element wires  27  ( 27   a ,  27   b ,  27   c ,  27   d ,  27   e ,  27   f ) are paired, but the configuration is not limited to this. Three of the third metal element wires  29  ( 29   a ,  29   b ,  29   c ,  29   d ,  29   e ,  29   f ) may be bundled, and three of the fourth metal element wires  27  ( 27   a ,  27   b ,  27   c ,  27   d ,  27   e ,  27   f ) may be bundled. However, the third metal element wires  29  and the fourth metal element wires  27  preferably cover the entire cross-sectional circumferences of the third rod  23  and the fourth rod  25  where connected. 
     Further, in the connection structure  21  described above, the third rod  23  comprises a stainless steel alloy, and the fourth rod  25  comprises a nickel-titanium alloy, and the multi-thread coil  24  is formed by winding the third metal element wires  29  comprising the stainless steel alloy and the fourth metal element wires  27  comprising the nickel-titanium alloy. However, the configuration is not limited to this. 
     For example, the third rod  23  may comprise a cobalt-chromium alloy, and the fourth rod  25  may comprise a nickel-titanium alloy, and the multi-thread coil  24  may be formed by winding the third metal element wires  29  comprising the cobalt-chromium alloy and the fourth metal element wires  27  comprising the nickel-titanium alloy. Alternatively, the third rod  23  may comprise a stainless steel alloy, and the fourth rod  25  may comprise a cobalt-chromium alloy, and the multi-thread coil  24  may be formed by winding the third metal element wires  29  comprising the stainless steel alloy and the fourth metal element wires  27  comprising the cobalt-chromium alloy. 
     In the connection structure  21  shown in  FIGS.  5  and  6   , the multi-thread coil  24  formed by winding the third metal element wires  29  comprising the first metal and the fourth metal element wires  27  comprising the second metal is arranged between the third rod  23  comprising the first metal such as a stainless steel alloy and the fourth rod  25  comprising the second metal such as a nickel-titanium alloy. Additionally, the third rod  23  is connected to only the third metal element wires  29  of the multi-thread coil  24 , and the fourth rod  25  is connected to only the fourth metal element wires  27  of the multi-thread coil  24 . This can improve the flexibility of a connected portion formed by the multi-thread coil  24 . 
     Moreover, the connection structure  21  can improve the flexibility of the connected portion, and can also provide an appropriate connection even when dissimilar metals are used such as a stainless steel alloy and a nickel-titanium alloy, which are difficult to directly connect to each other. 
       FIG.  7    shows a schematic side view of a guide wire  40  according to the disclosed embodiments, and  FIG.  8    shows a schematic cross-sectional side view of the guide wire  40 . 
     Note that in order to clearly indicate that a first cylinder portion  33   a , a first tapered portion  33   b , a second cylinder portion  33   c , a second tapered portion  33   d , a third cylinder portion  33   e , and fifth metal element wires  39  of a core shaft  33  as described below all comprise the same material, and that a fourth cylinder portion  33   g  and sixth metal element wires  37  of the core shaft  33  as described below all comprise the same material, only portions corresponding the fourth cylinder portion  33   g  and the sixth metal element wires  37  of the core shaft  33  are shaded in  FIGS.  7  and  8   . 
     As shown in  FIGS.  7  and  8   , a guide wire  40  comprises the core shaft  33  and a coil body  48  covering a distal (front) end of the core shaft  33 . 
     The coil body  48  is a single-thread coil body comprising a stainless steel alloy. 
     The core shaft  33  comprises, as listed from its distal end, the first cylinder portion  33   a , the first tapered portion  33   b , the second cylinder portion  33   c , the second tapered portion  33   d , the third cylinder portion  33   e , the fourth cylinder portion  33   g , a multi-thread coil body  33   f , and the fourth cylinder portion  33   g.    
     Here, the first cylinder portion  33   a , the first tapered portion  33   b , the second cylinder portion  33   c , the second tapered portion  33   d , and the third cylinder portion  33   e  form an elongated metal rod body with a round cross-section comprising a stainless steel alloy, and the fourth cylinder portion  33   g  is an elongated metal rod body with a round cross-section comprising a nickel-titanium alloy. 
     Further, the multi-thread coil  33   f  is formed by winding 6 fifth metal element wires  39  ( 39   a ,  39   b ,  39   c ,  39   d ,  39   e ,  39   f ) and 6 sixth metal element wires  37  ( 37   a ,  37   b ,  37   c ,  37   d ,  37   e ,  37   f ). 
     The coil body  48  is a single-thread coil body comprising the stainless steel alloy. A distal end of the coil body  48  is brazed to a distal end of the first cylinder portion  33   a  of the core shaft  33  to form a front brazing portion  42 . 
     Further, a proximal end part of the coil body  48  is brazed to the second cylinder portion  33   c  of the core shaft  33  to form a proximal end brazing portion  46 , and an intermediate part (a middle part) of the coil body  48  is brazed to the first tapered portion  33   b  of the core shaft  33  to form a middle brazing portion  44 . 
     Further, in the multi-thread coil  33   f , the fifth metal element wires  39  and the sixth metal element wires  37  are adjacently wound one by one. 
     The third cylinder portion  33   e  comprising the stainless steel alloy is welded to the fifth metal element wires  39  ( 39   a ,  39   b ,  39   c ,  39   d ,  39   e , and  39   f ) comprising the stainless steel alloy of the multi-thread coil  33   f , but is not welded to the sixth metal element wires  37  ( 37   a ,  37   b ,  37   c ,  37   d ,  37   e ,  37   f ) comprising the nickel-titanium alloy of the multi-thread coil  33   f.    
     Further, the fifth metal element wires  39  ( 39   a ,  39   b ,  39   c ,  39   d ,  39   e ,  39   f ) are welded to the third cylinder portion  33   e  so as to sandwich the sixth metal element wires  37  ( 37   a ,  37   b ,  37   c ,  37   d ,  37   e ,  37   f ) from both sides of each sixth metal element wire  37  at a connected portion of the third cylinder portion  33   e  and the multi-thread coil  33   f.    
     On the other hand, the fourth cylinder portion  33   g  comprising the nickel-titanium alloy is welded to the sixth metal element wires  37  ( 37   a ,  37   b ,  37   c ,  37   d ,  37   e ,  37   f ) comprising the nickel-titanium alloy of the multi-thread coil  33   f , but is not welded to the fifth metal element wires  39  ( 39   a ,  39   b ,  39   c ,  39   d ,  39   e ,  39   f ) comprising the stainless steel alloy of the multi-thread coil  33   f.    
     Further, the sixth metal element wires  37  ( 37   a ,  37   b ,  37   c ,  37   d ,  37   e ,  37   f ) are welded to the fourth cylinder portion  33   g  so as to sandwich the fifth metal element wires  39  ( 39   a ,  39   b ,  39   c ,  39   d ,  39   e ,  39   f ) from both sides of each fifth metal element wire  39  at a connected portion of the fourth cylinder portion  33   g  and the multi-thread coil  33   f.    
     Note that the multi-thread coil  33   f  shown in  FIGS.  7  and  8    is formed by winding a total of 12 metal element wires (6 fifth metal element wires  39  and 6 sixth metal element wires  37 , but the multi-thread coil  33   f  is not limited to this configuration. The multi-thread coil  33   f  can contain any number of the fifth metal element wires  39  and the sixth metal element wires  37  as long as the total number of each of the fifth metal element wires  39  and the sixth metal element wires  37  is 2 or more. However, the fifth metal element wires  39  and the sixth metal element wires  37  preferably cover the entire cross-sectional circumferences of the third cylinder portion  33   e  and the fourth cylinder portion  33   g  of the core shaft  33  where connected. 
     Further, in the guide wire  40  shown in  FIGS.  7  and  8   , the third cylinder portion  33   e  of the core shaft  33  comprises a stainless steel alloy, and the fourth cylinder portion  33   g  of the core shaft  33  comprises a nickel-titanium alloy, and the multi-thread coil  33   f  is formed by winding the fifth metal element wires  39  comprising the stainless steel alloy and the sixth metal element wires  37  comprising the nickel-titanium alloy. However, the configuration is not limited to this. 
     For example, the third cylinder portion  33   e  of the core shaft  33  may comprise a cobalt-chromium alloy, and the fourth cylinder portion  33   g  of the core shaft  33  may comprise a nickel-titanium alloy, and the multi-thread coil  33   f  may be formed by winding the fifth metal element wires  39  comprising the cobalt-chromium alloy and the sixth metal element wires  37  comprising the nickel-titanium alloy. Alternatively, the third cylinder portion  33   e  of the core shaft  33  may comprise a stainless steel alloy, and the fourth cylinder portion  33   g  of the core shaft  33  may comprise a cobalt-chromium alloy, and the multi-thread coil  33   f  may be formed by winding the fifth metal element wires  39  comprising the stainless steel alloy and the sixth metal element wires  37  comprising the cobalt-chromium alloy. 
     In the guide wire  40  shown in  FIGS.  7  and  8   , the multi-thread coil  33   f  formed by winding the fifth metal element wires  39  comprising the first metal and the sixth metal element wires  37  comprising the second metal is arranged between the third cylinder portion  33   e  of the core shaft  33  comprising the first metal such as a stainless steel alloy and the fourth cylinder portion  33   g  comprising the second metal such as a nickel titanium alloy. Additionally, the third cylinder portion  33   e  of the core shaft  33  is connected to only the fifth metal element wires  39  of the multi-thread coil  33   f , and the fourth cylinder portion  33   g  is connected to only the sixth metal element wires  37  of the multi-thread coil  33   f  This can improve the flexibility of the connected portion formed by the multi-thread coil  33   f , enabling the guide wire  40  to easily follow along a winding blood vessel. 
     Further, in the guide wire  40  shown in  FIGS.  7  and  8   , the multi-thread coil  33   f  comprises the fifth metal element wires  39  and the sixth metal element wires  37  adjacently wound one by one, and the fifth metal element wires  39  are connected to the third cylinder portion  33   e  of the core shaft  33  so as to sandwich the sixth metal element wires  37 , and the sixth metal element wires  37  are connected to the fourth cylinder portion  33   g  so as to sandwich the fifth metal element wires  39 . This can prevent distortion of the shape of the multi-thread coil  33   f  as much as possible, and can also improve the flexibility of the connected portion. 
     Note that as described above, an example is presented where a connection structure corresponding to the connection structure  1  is used in the guide wire  40 , but the configuration is not limited to this. The connection structure  24  may also be used in a guide wire. In that case, the advantageous effects of the connection structure  24  will be manifested therein. 
     Guide wires according to the disclosed embodiments are described above, but the present invention shall not be limited to the above examples. Various modifications can be made to the above-described examples without departing from the spirit of the present invention. 
     For example, the metal element wires  7 ,  9 ,  27 ,  29 ,  37 ,  39  of the multi-thread coil  4 ,  24 ,  33   f  are welded to the rod bodies  3 ,  5 ,  23 ,  25  or the elongated metal rod bodies forming the core shaft  33  in the embodiments described above, but they may be connected by a method other than welding. However, welding is preferred considering that metals can be easily connected.