Hollow twisted strand

Abstract

To provide a hollow twisted strand 2 that can contribute to torque transmission properties of equipment.SOLUTION: A hollow twisted strand 2 has a first layer 4 and a second layer 6. The second layer 6 is located outside the first layer 4. The first layer 4 is formed by twisting three or more first element wires 10. The second layer 6 is formed by twisting three or more second element wires 12. In the first layer 4, a side surface of the first element wire 10 in front contacts a side surface of the first element wire 10 at the back. In the second layer 6, the side surface of the second element wire 12 in front contacts the side surface of the second element wire 12 at the back.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] This specification discloses a hollow stranded wire suitable for medical devices and the like. [Background technology]

[0002] Medical devices that are inserted into body cavities, such as guidewires, are required to have flexibility, responsiveness, torque transmission, pushability, etc. JP2019-107326A discloses a hollow stranded wire suitable for medical devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP2019-107326A Summary of the Invention [Problem to be solved by the invention]

[0004] In medical devices using conventional hollow stranded wires, torque transmission is insufficient. The applicant's intention is to provide a hollow stranded wire that can contribute to the torque transmission of various devices such as medical devices. [Means for solving the problem]

[0005] The hollow stranded wire disclosed in this specification has a first layer formed by twisting three or more first strands, and a second layer formed by twisting three or more second strands and located outside or inside the first layer. Each first strand has an inner surface, an outer surface, a front side surface, and a rear side surface. The front side surface or the rear side surface is inclined with respect to the radial direction of the hollow stranded wire. The front side surface of the rear first strand abuts on the rear side surface of the front first strand. Effect of the Invention

[0006] When one end of this hollow stranded wire is rotated, a time lag in rotation is unlikely to occur. A device using this hollow stranded wire has excellent torque transmission properties. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a front view showing a part of a hollow stranded wire according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view along the longitudinal direction of the hollow strand of FIG. [Diagram 3] FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged view of a portion indicated by an arrow IV in FIG. [Diagram 5] 5 is a perspective view showing a part of a first wire of the hollow stranded wire of FIG. [Figure 6] FIG. 6 is an enlarged cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 8] FIG. 8 is a cross-sectional view showing a part of a hollow stranded wire according to another embodiment. [Figure 9] FIG. 9 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 10] FIG. 10 is a cross-sectional view showing a part of a hollow stranded wire according to still another embodiment. [Figure 11] 11 is a perspective view showing a part of a first wire of the hollow stranded wire of FIG. [Figure 12] FIG. 12 is an enlarged cross-sectional view taken along line XII-XII in FIG. [Figure 13] FIG. 13 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 14] FIG. 14 is a cross-sectional view showing a part of a hollow stranded wire according to still another embodiment. [Figure 15] FIG. 15 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 16]FIG. 16 is a cross-sectional view showing a part of a hollow stranded wire according to still another embodiment. [Figure 17] FIG. 17 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 18] FIG. 18 is a cross-sectional view showing a part of a hollow stranded wire according to still another embodiment. [Figure 19] FIG. 19 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 20] FIG. 20 is a front view showing a portion of a hollow stranded wire according to still another embodiment. [Figure 21] FIG. 21 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 22] FIG. 22 is an enlarged view showing a part of the hollow stranded wire of FIG. [Figure 23] FIG. 23 is a perspective view showing an apparatus for evaluating the torque transmissibility of the hollow stranded wire of FIG. [Figure 24] FIG. 24 is a graph showing an example of the measurement results obtained by the device of FIG. [Diagram 25] FIG. 25 is a front view showing an apparatus for evaluating the pushability of the hollow strand of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, preferred embodiments will be described in detail with reference to the drawings as appropriate.

[0009] [First embodiment] A hollow stranded wire 2 is shown in Figures 1-4. The hollow stranded wire 2 is made of a metal material. A preferred metal is stainless steel. The hollow stranded wire 2 is long. In Figure 1, arrow X indicates the axial direction of the hollow stranded wire 2, and arrow Y indicates the radial direction of the hollow stranded wire 2. In Figure 1, the right side is the front of the hollow stranded wire 2, and the left side is the rear of the hollow stranded wire 2. The hollow stranded wire 2 can be cut to a predetermined length and used as a part of a medical device. Torque applied to one end of the hollow stranded wire 2 is transmitted to the other end.

[0010] This hollow stranded wire 2 has a first layer 4 and a second layer 6. The second layer 6 is located outside the first layer 4. The first layer 4 is formed by twisting a plurality of first elemental wires 10. The second layer 6 is formed by twisting a plurality of second elemental wires 12.

[0011] As shown in Figures 1 and 2, the first wires 10 are twisted clockwise toward the front, and the second wires 12 are twisted counterclockwise toward the front. In other words, the twist direction of the second wires 12 is opposite to that of the first wires 10. In this specification, the twist direction of the first wires 10 is referred to as the "Z direction", and the twist direction of the second wires 12 is referred to as the "S direction". The first wires 10 may be twisted in the "S direction", and the second wires 12 may be twisted in the "Z direction". The first wires 10 may be twisted in the "S direction", and the second wires 12 may be twisted in the "S direction". The first wires 10 may be twisted in the "Z direction", and the second wires 12 may be twisted in the "Z direction".

[0012] The first strand 10 is shown in Figures 5-7. As shown in Figure 5, the first strand 10 is long. As shown in Figure 6, the cross section of the first strand 10 is generally a parallelogram. The second strand 12 also has the shape shown in Figures 5-7. In other words, Figure 5 is also a perspective view showing the second strand 12, and Figures 6 and 7 are also cross-sectional views showing the second strand 12. The cross-sectional shape of the second strand 12 may be different from the cross-sectional shape of the first strand 10.

[0013] The first wire 10 has an inner surface 14, an outer surface 16, a front side surface 18, and a rear side surface 20. In the cross section of FIG. 6, the outer surface 16 is generally parallel to the inner surface 14. Furthermore, the rear side surface 20 is generally parallel to the front side surface 18. In FIG. 6, an arrow La indicates the length of the first wire 10. This length La is also the length of the inner surface 14 and the length of the outer surface 16. In FIG. 6, an arrow T indicates the thickness of the first wire 10. The ratio (La / T) of the length La to the thickness T is preferably 1.0 or more, more preferably 1.5 or more, and particularly preferably 1.8 or more. This ratio (La / T) is preferably 10.0 or less.

[0014] In Fig. 7, the right side is the front of the hollow stranded wire 2, the left side is the rear of the hollow stranded wire 2, the upper side is the radially outer side of the hollow stranded wire 2, and the lower side is the radially inner side of the hollow stranded wire 2. Fig. 7 shows two first strands 10 belonging to the first layer 4. Specifically, the front first strand 10a and the rear first strand 10b are shown. The distance from the axis line CL (see Figs. 1 and 2) to the first strand 10b is equal to the distance from the axis line CL to the first strand 10a.

[0015] In each of the first wires 10, the inner surface 14 is parallel to the axial direction X of the hollow stranded wire 2, and the outer surface 16 is also parallel to the axial direction X. In this first wire 10, the front side surface 18 is inclined with respect to the radial direction Y of the hollow stranded wire 2, and the rear side surface 20 is also inclined with respect to the radial direction Y. The inclination direction of the front side surface 18 or the rear side surface 20 is toward the front, toward the inside in the radial direction (see also FIG. 4). Due to this inclination, the front end 22 of the first wire 10b is located forward of the rear end 24 of the first wire 10a. In other words, in the axial direction X of the hollow stranded wire 2, the position of the first wire 10a and the position of the first wire 10b overlap. In the radial direction of the hollow stranded wire 2, the front end 22 of the first wire 10b is located inside the rear end 24 of the first wire 10a. The front side surface 18 of the first wire 10b abuts against the rear side surface 20 of the first wire 10a. The front side surface 18 of the first wire 10b is in contact with the rear side surface 20 of the first wire 10a over a wide area.

[0016] In this first layer 4, when the hollow stranded wire 2 is rotated, force is sufficiently transmitted between the first wires 10 and the adjacent first wires 10. In this first layer 4, a rotation time lag is unlikely to occur. This hollow stranded wire 2 can contribute to the torque transmissibility of medical devices. As is clear from FIG. 2, the first wires 10 overlap over the entire length of the hollow stranded wire 2. The first layer 4 may include locations where there is no overlap due to manufacturing errors, etc.

[0017] In Fig. 7, arrow L1 indicates the overlap distance between the position of the front first wire 10a and the position of the rear first wire 10b in the axial direction of the hollow stranded wire 2. The ratio of this overlap distance L1 to the length La of the first wire 10 (see Fig. 6) is preferably 1.0% or more and 55% or less. When this ratio is 1.0% or more, the first layer 4 can contribute to torque transmissibility. From this viewpoint, this ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. When this ratio is 55% or less, the hollow stranded wire 2 has excellent flexibility. From this viewpoint, this ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0018] As is clear from Figs. 4 and 7, in the second layer 6 as well, the positions of two adjacent second wires 12 overlap in the axial direction X of the hollow stranded wire 2. The front side surface 18 (see also Fig. 6) of the second wire 12 abuts against the rear side surface 20 of another second wire 12. In the second layer 6, when the hollow stranded wire 2 is rotated, a force is sufficiently transmitted between the second wire 12 and the adjacent second wire 12. In the second layer 6, a time lag in rotation is unlikely to occur. The hollow stranded wire 2 can contribute to the torque transmission of medical devices. In the second layer 6 as well, the ratio of the overlap distance L1 between the second wire 12 and another second wire 12 to the length La of the second wire 12 is preferably 1.0% or more and 55% or less. This ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. This ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0019] In FIG. 7, the arrow α1 indicates the angle of the front side surface 18 with respect to the radial direction Y of the hollow stranded wire 2. As described above, the rear side surface 20 is parallel to the front side surface 18. Therefore, the angle α1 is also the angle of the rear side surface 20 with respect to the radial direction Y of the hollow stranded wire 2. The angle of the rear side surface 20 may be slightly different from the angle α1. The absolute value of the angle α1 is preferably 5° or more. The first layer 4 and the second layer 6, whose absolute value is 5° or more, can contribute to torque transmissibility. From this viewpoint, the absolute value is more preferably 10° or more, and particularly preferably 15° or more. From the viewpoint of the flexibility of the hollow stranded wire 2, the absolute value is preferably 45° or less.

[0020] In this embodiment, there is overlap of the strands in both the first layer 4 and the second layer 6. There may be overlap of the strands only in the first layer 4. There may be overlap of the strands only in the second layer 6.

[0021] In Fig. 1, arrow β1 indicates the twist angle of the first layer 4. The absolute value of twist angle β1 is preferably 85° or less. The first wires 10 having an absolute value of 85° or less can contribute to torque transmissibility and pushability. From this viewpoint, the absolute value is more preferably 82° or less, and particularly preferably 80° or less. The absolute value is preferably 50° or more.

[0022] As shown in FIG. 1 , the first layer 4 is formed by twisting six first wires 10 (101, 102, 103, 104, 105, 106). In other words, the number of threads in the first layer 4 is six. This number of threads is preferably three or more. In the first layer 4 having three or more threads, an angle β1 with a small absolute value can be achieved. From this viewpoint, the number of threads is more preferably five or more, and particularly preferably six or more. The number of threads is preferably 16 or less.

[0023] In Fig. 1, an arrow β2 indicates the twist angle of the second layer 6. The absolute value of twist angle β2 is preferably 85° or less. The second wires 12 having an absolute value of 85° or less can contribute to torque transmissibility and pushability. From this viewpoint, the absolute value is more preferably 82° or less, and particularly preferably 80° or less. The absolute value is preferably 50° or more.

[0024] As shown in FIG. 1 , the second layer 6 is formed by twisting six second wires 12 (121, 122, 123, 124, 125, 126). In other words, the number of threads in the second layer 6 is six. This number of threads is preferably three or more. In the second layer 6 having three or more threads, an angle β2 with a small absolute value can be achieved. From this viewpoint, the number of threads is more preferably five or more, and particularly preferably six or more. The number of threads is preferably 16 or less.

[0025] As described above, the twisting direction of the second wires 12 is opposite to that of the first wires 10. When the hollow stranded wire 2 is rotated counterclockwise, a rotational time lag is unlikely to occur in the first layer 4. Therefore, the first layer 4 contributes to torque transmissibility. When the hollow stranded wire 2 is rotated clockwise, a rotational time lag is unlikely to occur in the second layer 6. Therefore, the second layer 6 contributes to torque transmissibility. The hollow stranded wire 2 has excellent torque transmissibility regardless of the rotation direction.

[0026] The two-dot chain line indicated by the symbol CC in Fig. 3 is the circumscribing circle of the hollow stranded wire 2. The circumscribing circle CC is the smallest circle that can contain the entire cross-sectional contour of the hollow stranded wire 2 inside. The arrow Dc indicates the diameter of the circumscribing circle CC. In this specification, this diameter Dc is referred to as the "outer diameter of the hollow stranded wire." From the viewpoint of facilitating insertion of a medical device using the hollow stranded wire 2 into a body cavity, the outer diameter Dc is preferably 5.0 mm or less, more preferably 3.0 mm or less, and particularly preferably 2.0 mm or less.

[0027] The two-dot chain line indicated by the symbol IC in Fig. 3 is the inscribed circle of the hollow stranded wire 2. The inscribed circle IC is the largest circle that can be drawn inside the cross section of the hollow stranded wire 2. The arrow Di indicates the diameter of this inscribed circle IC. In this specification, this diameter Di is referred to as the "inner diameter of the hollow stranded wire." From the viewpoint of facilitating passage of other members inside, the inner diameter Di is preferably 0.2 mm or more, more preferably 0.5 mm or more, and particularly preferably 1.0 mm or more.

[0028] In the present invention, the average diameter D of the hollow stranded wire 2 is calculated by the following formula. D = (Dc + Di) / 2 In the present invention, the thickness T of the hollow stranded wire 2 is calculated by the following formula. T = (Dc - Di) / 2

[0029] The ratio (D / T) of the average diameter D to the thickness T is preferably 5 or more and 20 or less. In a hollow stranded wire 2 with a ratio (D / T) of 5 or more, other members can be easily passed through the inside. From this viewpoint, the ratio (D / T) is more preferably 6 or more, and particularly preferably 8 or more. A hollow stranded wire 2 with a ratio (D / T) of 20 or less has excellent pushability. From this viewpoint, the ratio (D / T) is more preferably 18 or less, and particularly preferably 16 or less.

[0030] A typical application of the hollow stranded wire 2 is a guide wire used in catheter examinations. Other applications include the shaft of a catheter for removing blood clots, the shaft of a catheter for IVUS (intravascular ultrasound), a wire for operating devices in an endoscope, and industrial operating parts.

[0031] [Second embodiment] 8 shows a hollow stranded wire 26 according to another embodiment. The hollow stranded wire 26 has a first layer 28 and a second layer 30. The second layer 30 is located outside the first layer 28. The first layer 28 is formed by twisting a plurality of first strands 32. The second layer 30 is formed by twisting a plurality of second strands 34. The configuration of the first layer 28 is the same as that of the first layer 4 shown in FIGS. 1-7.

[0032] 9 shows two second wires 34 belonging to the second layer 30. Specifically, a front second wire 34a and a rear second wire 34b are shown. The distance from the axis line CL to the second wire 34b is equal to the distance from the axis line CL to the second wire 34a. Each second wire 34 has an inner surface 36, an outer surface 38, a front side surface 40, and a rear side surface 42.

[0033] In each second strand 34, the inner surface 36 is parallel to the axial direction X of the hollow strand 26, and the outer surface 38 is also parallel to the axial direction X. In this second strand 34, the front side surface 40 is inclined with respect to the radial direction Y of the hollow strand 26, and the rear side surface 42 is also inclined with respect to the radial direction Y. The inclination direction of the front side surface 40 or the rear side surface 42 is toward the front and radially outward. Due to this inclination, the front end 44 of the second strand 34b is located forward of the rear end 46 of the second strand 34a. In other words, in the axial direction X of the hollow strand 26, the position of the second strand 34a and the position of the second strand 34b overlap. In the radial direction of the hollow strand 26, the front end 44 of the second strand 34b is located outside the rear end 46 of the second strand 34a. The front side surface 40 of the second wire 34b abuts against the rear side surface 42 of the second wire 34a. The front side surface 40 of the second wire 34b is in contact with the rear side surface 42 of the second wire 34a over a wide area.

[0034] In the second layer 30, when the hollow stranded wire 26 is rotated, force is sufficiently transmitted between the second strands 34 and the adjacent second strands 34. In the second layer 30, a rotation time lag is unlikely to occur. The hollow stranded wire 26 can contribute to the torque transmission of medical devices. It is preferable that the second strands 34 overlap over the entire length of the hollow stranded wire 26. The second layer 30 may include portions where there is no overlap due to manufacturing errors or the like.

[0035] 9, arrow L2 indicates the overlap distance between the position of the front second wire 34a and the position of the rear second wire 34b in the axial direction of the hollow stranded wire 26. The ratio of this overlap distance L2 to the length La of the second wire 34 is preferably 1.0% or more and 55% or less. This ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. This ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0036] In FIG. 9, the arrow α2 indicates the angle of the front side surface 40 with respect to the radial direction Y of the hollow stranded wire 26. The rear side surface 42 is parallel to the front side surface 40. Therefore, the angle α2 is also the angle of the rear side surface 42 with respect to the radial direction Y of the hollow stranded wire 26. The angle of the rear side surface 42 may be slightly different from the angle α2. The absolute value of the angle α2 is preferably 5° or more. The second layer 30 having an absolute value of 5° or more can contribute to torque transmissibility. From this viewpoint, the absolute value is more preferably 10° or more, and particularly preferably 15° or more. From the viewpoint of the flexibility of the hollow stranded wire 26, the absolute value is preferably 45° or less.

[0037] 8, in this hollow stranded wire 26, the side surfaces of the first wires 32 are inclined radially inward toward the front, and the side surfaces of the second wires 34 are inclined radially outward toward the front. The inclination direction of the second wires 34 is opposite to the inclination direction of the first wires 32. This hollow stranded wire 26 has excellent torque transmission properties regardless of the rotation direction.

[0038] The twist direction of the first wires 32 may be either the "Z direction" or the "S direction". The twist direction of the second wires 34 may be either the "Z direction" or the "S direction". From the viewpoint of uniform torque transmissibility, it is preferable that the twist direction of the second wires 34 is opposite to the twist direction of the first wires 32.

[0039] [Third embodiment] 10 shows a hollow stranded wire 48 according to yet another embodiment. The hollow stranded wire 48 has a first layer 50 and a second layer 52. The second layer 52 is located outside the first layer 50. The first layer 50 is formed by twisting a plurality of first strands 54. The second layer 52 is formed by twisting a plurality of second strands 56.

[0040] The first strand 54 is shown in Figures 11-13. As shown in Figure 11, the first strand 54 is long. As shown in Figure 12, the cross section of the first strand 54 is generally an isosceles trapezoid. The second strand 56 also has the shape shown in Figures 11-13. In other words, Figure 11 is also a perspective view showing the second strand 56, and Figures 12 and 13 are also cross-sectional views showing the second strand 56. The cross-sectional shape of the second strand 56 may be different from the cross-sectional shape of the first strand 54.

[0041] The first wire 54 has a bottom surface 58, a top surface 60, a front side surface 62, and a rear side surface 64. In the cross section of FIG. 12, the top surface 60 is generally parallel to the bottom surface 58. The rear side surface 64 is not parallel to the front side surface 62. In FIG. 12, an arrow La indicates the length of the first wire 54. This length La is the longer of the bottom surface 58 and the top surface 60.

[0042] In FIG. 13, the right side is the front of the hollow stranded wire 48, the left side is the rear of the hollow stranded wire 48, the upper side is the radially outer side of the hollow stranded wire 48, and the lower side is the radially inner side of the hollow stranded wire 48. FIG. 13 shows two first strands 54 belonging to the first layer 50. Specifically, a front first strand 54a and a rear first strand 54b are shown. In the front first strand 54a, the bottom surface 58 is the inner surface, and the top surface 60 is the outer surface. In the rear first strand 54b, the bottom surface 58 is the outer surface, and the top surface 60 is the inner surface. The distance from the axis line CL (see FIGS. 1 and 2) to the first strand 54b is equal to the distance from the axis line CL to the first strand 54a.

[0043] In each of the first strands 54, the bottom surface 58 is parallel to the axial direction X of the hollow strand 48, and the top surface 60 is also parallel to the axial direction X. In each of the first strands 54, the front side surface 62 is inclined with respect to the radial direction Y of the hollow strand 48, and the rear side surface 64 is also inclined with respect to the radial direction Y. The front side surface 62 of the front first layer 50a is inclined radially inward toward the front. The rear side surface 64 of the front first layer 50a is inclined radially outward toward the front. The front side surface 62 of the rear first layer 50b is inclined radially outward toward the front. The rear side surface 64 of the rear first layer 50b is inclined radially inward toward the front. In the axial direction X of the hollow strand 48, the positions of the first strands 54a and the first strands 54b overlap each other. A front side surface 62 of the first wire 54b abuts against a rear side surface 64 of the first wire 54a. The front side surface 62 of the first wire 54b is in contact with the rear side surface 64 of the first wire 54a over a wide area.

[0044] In this first layer 50, when the hollow stranded wire 48 is rotated, force is sufficiently transmitted between the first strands 54 and the adjacent first strands 54. A rotational time lag is unlikely to occur in this first layer 50. This hollow stranded wire 48 can contribute to the torque transmissibility of a medical device.

[0045] In Fig. 13, an arrow L3 indicates the overlap distance between the position of the front first wires 54a and the position of the rear first wires 54b in the axial direction of the hollow stranded wire 48. The ratio of this overlap distance L3 to the length La of the first wires 54 is preferably 1.0% or more and 30% or less. The first layer 50 having this ratio of 1.0% or more can contribute to torque transmissibility. From this viewpoint, this ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. The hollow stranded wire 48 having this ratio of 30% or less has excellent flexibility. From this viewpoint, this ratio is more preferably 25% or less, and particularly preferably 20% or less.

[0046] As is clear from Figs. 10 and 13, in the second layer 52 as well, the positions of two adjacent second wires 56 overlap in the axial direction X of the hollow stranded wire 48. A front side surface 62 (see also Fig. 12) of the second wire 56 abuts against a rear side surface 64 of another second wire 56. In the second layer 52, when the hollow stranded wire 48 is rotated, a force is sufficiently transmitted between the second wire 56 and the adjacent second wire 56. In the second layer 52, a time lag in rotation is unlikely to occur. The hollow stranded wire 48 can contribute to the torque transmission of the medical device. In the second layer 52 as well, the ratio of the overlap distance L3 between the second wire 56 and the other second wire 56 to the length La of the second wire 56 is preferably 1.0% or more and 30% or less. This ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. This ratio is more preferably 25% or less, and particularly preferably 20% or less.

[0047] In FIG. 13, the arrow α3 indicates the angle of the front side surface 62 of the front first wire 54a with respect to the radial direction Y of the hollow stranded wire 48. As described above, the cross-sectional shape of the first wire 54 is an isosceles trapezoid. Therefore, the inclination direction of the rear side surface 64 of the front first wire 54a is opposite to the inclination direction of the front side surface 62 of the front first wire 54a. The inclination direction of the front side surface 62 of the rear first wire 54b is opposite to the inclination direction of the front side surface 62 of the front first wire 54a. The inclination direction of the rear side surface 64 of the rear first wire 54b is the same as the inclination direction of the front side surface 62 of the front first wire 54a. The absolute value of the angle of the rear side surface 64 of the front first wire 54a with respect to the radial direction Y of the hollow stranded wire 48 is the same as the absolute value of the angle α3. The absolute value of the angle of the front side surface 62 of the rear first strand 54b with respect to the radial direction Y of the hollow strand 48 is the same as the absolute value of the angle α3. The absolute value of the angle of the rear side surface 64 of the rear first strand 54b with respect to the radial direction Y of the hollow strand 48 is the same as the absolute value of the angle α3. These absolute values ​​may differ from each other to some extent. The absolute value of the angle α3 is preferably 5° or more. The first layer 50 and the second layer 52, whose absolute value is 5° or more, can contribute to torque transmissibility. From this viewpoint, the absolute value is more preferably 10° or more, and particularly preferably 15° or more. From the viewpoint of the flexibility of the hollow strand 48, the absolute value is preferably 30° or less.

[0048] The twist direction of the first wires 54 may be either the "Z direction" or the "S direction". The twist direction of the second wires 56 may be either the "Z direction" or the "S direction". From the viewpoint of uniform torque transmissibility, it is preferable that the twist direction of the second wires 56 is opposite to the twist direction of the first wires 54.

[0049] [Fourth embodiment] 14 shows a hollow stranded wire 66 according to yet another embodiment. The hollow stranded wire 66 has a first layer 68 and a second layer 70. The second layer 70 is located outside the first layer 68. The first layer 68 is formed by twisting a plurality of first strands 72a and a plurality of other first strands 72b. The second layer 70 is formed by twisting a plurality of second strands 74a and a plurality of other second strands 74b.

[0050] FIG. 15 shows a part of the first layer 68. Specifically, a first strand 72a and another first strand 72b are shown in this figure. The shape of the first strand 72a is the same as the strand 10 shown in FIGS. 5 and 6. The first strand 72a has a generally parallelogram cross-sectional shape. The shape of the first strand 72b is the same as the strand 54 shown in FIGS. 11 and 12. The first strand 72b has a generally isosceles trapezoid cross-sectional shape. As is clear from FIG. 14, the cross-sectional shape of the second strand 74a is the same as the cross-sectional shape of the first strand 72a, and the cross-sectional shape of the second strand 74b is the same as the cross-sectional shape of the second strand 74a. In other words, FIG. 15 is also a cross-sectional view showing the second layer 70.

[0051] The first wire 72a has an inner surface 76, an outer surface 78, a front side surface 80, and a rear side surface 82. The other first wire 72b has a bottom surface 84, a top surface 86, a front side surface 88, and a rear side surface 90. The side surface 82 of the first wire 72a abuts against a side surface 88 of the other first wire 72b. The side surface 82 of the first wire 72a abuts against a side surface 88 of the other first wire 72b over a wide area. In the axial direction X of the hollow strand 66, the first wire 72a and the first wire 72b overlap each other.

[0052] In this first layer 68, when the hollow stranded wire 66 is rotated, force is sufficiently transmitted between the strand and the adjacent strands. A rotation time lag is unlikely to occur in this first layer 68. This hollow stranded wire 66 can contribute to the torque transmission of a medical device.

[0053] In Fig. 15, an arrow L4 indicates the overlap distance between the position of a first wire 72a and the position of another first wire 72b in the axial direction of the hollow stranded wire 66. The ratio of this overlap distance L4 to the length La of the first wire 72a is preferably 1.0% or more and 30% or less. The first layer 68 having this ratio of 1.0% or more can contribute to torque transmissibility. From this viewpoint, this ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. The hollow stranded wire 66 having this ratio of 30% or less has excellent flexibility. From this viewpoint, this ratio is more preferably 25% or less, and particularly preferably 20% or less.

[0054] As is clear from Figs. 14 and 15, in the second layer 70 as well, the positions of two adjacent second wires 74 overlap in the axial direction X of the hollow stranded wire 66. The side surface of the second wire 74a abuts against the side surface of another second wire 74b. In the second layer 70, when the hollow stranded wire 66 is rotated, a force is sufficiently transmitted between the second wire 74 and the adjacent second wire 74. In the second layer 70, a time lag in rotation is unlikely to occur. The hollow stranded wire 66 can contribute to the torque transmission of medical devices. In the second layer 70 as well, the ratio of the overlap distance L4 between the second wire 74 and the other second wire 74 to the length La of the second wire 74 is preferably 1.0% or more and 30% or less. This ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. This ratio is more preferably 25% or less, and particularly preferably 20% or less.

[0055] In FIG. 15, the arrow α4 indicates the angle of the front side surface 80 of the front first wire 72a with respect to the radial direction Y of the hollow stranded wire 66. As described above, the cross-sectional shape of the first wire 72a is a parallelogram, and the cross-sectional shape of the first wire 72b is an isosceles trapezoid. Therefore, the inclination direction of the rear side surface 82 of the first wire 72a is the same as the inclination direction of the front side surface 80 of the front first wire 72a. The inclination direction of the front side surface 88 of the first wire 72b is the same as the inclination direction of the front side surface 80 of the front first wire 72a. The inclination direction of the rear side surface 90 of the first wire 72b is opposite to the inclination direction of the front side surface 80 of the front first wire 72a. The absolute value of the angle of the rear side surface 82 of the first wire 72a with respect to the radial direction Y of the hollow stranded wire 66 is the same as the absolute value of the angle α4. The absolute value of the angle of the front side surface 88 of the first strand 72b with respect to the radial direction Y of the hollow strand 66 is the same as the absolute value of the angle α4. The absolute value of the angle of the rear side surface 90 of the rear first strand 72b with respect to the radial direction Y of the hollow strand 66 is the same as the absolute value of the angle α4. These absolute values ​​may differ from each other to some extent. The absolute value of the angle α4 is preferably 5° or more. The first layer 68 and the second layer 70, whose absolute value is 5° or more, can contribute to torque transmissibility. From this viewpoint, the absolute value is more preferably 10° or more, and particularly preferably 15° or more. From the viewpoint of the flexibility of the hollow strand 66, the absolute value is preferably 30° or less.

[0056] The twist direction of the first wires 72 may be either the "Z direction" or the "S direction". The twist direction of the second wires 74 may be either the "Z direction" or the "S direction". From the viewpoint of uniform torque transmissibility, it is preferable that the twist direction of the second wires 74 is opposite to the twist direction of the first wires 72.

[0057] [Fifth embodiment] 16 shows a hollow stranded wire 92 according to yet another embodiment. The hollow stranded wire 92 has a first layer 94 and a second layer 96. The second layer 96 is located outside the first layer 94. The first layer 94 is formed by twisting a plurality of first strands 98a and a plurality of other first strands 98b. The second layer 96 is formed by twisting a plurality of second strands 100a and a plurality of other second strands 100b.

[0058] FIG. 17 shows a part of the first layer 94. Specifically, a first strand 98a and another first strand 98b are shown in this figure. The shape of the first strand 98a is the same as the shape of the strand 10 shown in FIGS. 5 and 6. The first strand 98a has a cross-sectional shape that is generally a parallelogram. The other first strands 98b have a cross-sectional shape that is generally a trapezoid. This trapezoid is not an isosceles trapezoid. As is clear from FIG. 16, the cross-sectional shape of the second strand 100a is the same as the cross-sectional shape of the first strand 98a, and the cross-sectional shape of the second strand 100b is the same as the cross-sectional shape of the first strand 98b. In other words, FIG. 17 is also a cross-sectional view showing the second layer 96.

[0059] The first wire 98a has an inner surface 102, an outer surface 104, a front side surface 106, and a rear side surface 108. The other first wire 98b has a bottom surface 110, a top surface 112, a front side surface 114, and a rear side surface 116. The side surface 108 of the first wire 98a abuts against the side surface 114 of the other first wire 98b. The side surface 108 of the first wire 98a abuts against the side surface 114 of the other first wire 98b over a wide area. In the axial direction X of the hollow stranded wire 92, the first wire 98a and the first wire 98b overlap each other.

[0060] In this first layer 94, when the hollow stranded wire 92 is rotated, force is sufficiently transmitted between the strand and the adjacent strands. A rotation time lag is unlikely to occur in this first layer 94. This hollow stranded wire 92 can contribute to the torque transmission of a medical device.

[0061] In Fig. 17, an arrow L5 indicates the overlap distance between the position of a first wire 98a and the position of another first wire 98b in the axial direction of the hollow stranded wire 92. The ratio of this overlap distance L5 to the length La of the first wire 98a is preferably 1.0% or more and 55% or less. When this ratio is 1.0% or more, the first layer 94 can contribute to torque transmissibility. From this viewpoint, this ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. When this ratio is 55% or less, the hollow stranded wire 92 has excellent flexibility. From this viewpoint, this ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0062] As is clear from Figs. 16 and 17, in the second layer 96 as well, the positions of two adjacent second wires 100 overlap in the axial direction X of the hollow stranded wire 92. The side surface of the second wire 100a abuts against the side surface of another second wire 100b. In the second layer 96, when the hollow stranded wire 92 is rotated, a force is sufficiently transmitted between the second wire 100 and the adjacent second wire 100. In the second layer 96, a time lag in rotation is unlikely to occur. The hollow stranded wire 92 can contribute to the torque transmission of medical devices. In the second layer 96 as well, the ratio of the overlap distance L5 between the second wire 100 and the other second wire 100 to the length La of the second wire 100 is preferably 1.0% or more and 55% or less. This ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. This ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0063] In FIG. 17, the arrow α5 indicates the angle of the front side surface 106 of the front first strand 98a with respect to the radial direction Y of the hollow strand 92. As described above, the cross-sectional shape of the first strand 98a is a parallelogram, and the cross-sectional shape of the first strand 98b is a trapezoid. Therefore, the inclination direction of the rear side surface 108 of the first strand 98a is the same as the inclination direction of the front side surface 106 of the front first strand 98a. The inclination direction of the front side surface 114 of the first strand 98b is the same as the inclination direction of the front side surface 106 of the front first strand 98a. The absolute value of the angle of the rear side surface 108 of the first strand 98a with respect to the radial direction Y of the hollow strand 92 is the same as the absolute value of the angle α5. The absolute value of the angle of the front side surface 114 of the first strand 98b with respect to the radial direction Y of the hollow strand 92 is the same as the absolute value of the angle α5. These absolute values ​​may be slightly different from each other. The absolute value of the angle α5 is preferably 5° or more. The first layer 94 and the second layer 96, whose absolute value is 5° or more, can contribute to torque transmissibility. From this viewpoint, the absolute value is more preferably 10° or more, and particularly preferably 15° or more. From the viewpoint of flexibility of the hollow stranded wire 92, the absolute value is preferably 45° or less.

[0064] The twist direction of the first wires 98 may be either the "Z direction" or the "S direction". The twist direction of the second wires 100 may be either the "Z direction" or the "S direction". From the viewpoint of uniform torque transmissibility, it is preferable that the twist direction of the second wires 100 is opposite to the twist direction of the first wires 98.

[0065] [Sixth embodiment] 18 shows a hollow stranded wire 118 according to yet another embodiment. The hollow stranded wire 118 has a first layer 120 and a second layer 122. The second layer 122 is located outside the first layer 120. The first layer 120 is formed by twisting a plurality of first strands 124. The second layer 122 is formed by twisting a plurality of second strands 126.

[0066] FIG. 19 shows two first wires 124 belonging to the first layer 120. Specifically, a front first wire 124a and a rear first wire 124b are shown. Each first wire 124 has a bottom surface 128, a top surface 130, a front side surface 132, and a rear side surface 134. In the front first wire 124a, the bottom surface 128 is the inner surface, and the top surface 130 is the outer surface. In the rear first wire 124b, the bottom surface 128 is the outer surface, and the top surface 130 is the inner surface. This first wire 124 has a generally trapezoidal cross-sectional shape. This trapezoid is not an isosceles trapezoid. As is clear from FIG. 18, the cross-sectional shape of the second wire 126 is the same as the cross-sectional shape of the first wire 124. In other words, FIG. 19 is also a cross-sectional view showing the second layer 122.

[0067] The side surface 134 of the first strand 124a abuts against the side surface 132 of the other first strand 124b. The side surface 134 of the first strand 124a abuts against the side surface 132 of the other first strand 124b over a wide area. In the axial direction X of the hollow strand 118, the positions of the first strand 124a and the first strand 124b overlap. In this first layer 120, when the hollow strand 118 is rotated, force is sufficiently transmitted between the strand and the adjacent strand. In this first layer 120, a time lag in rotation is unlikely to occur. This hollow strand 118 can contribute to the torque transmission of medical devices.

[0068] In Fig. 19, an arrow L6 indicates the overlap distance between the position of the first wire 124a and the position of the other first wire 124b in the axial direction of the hollow stranded wire 118. The ratio of this overlap distance L6 to the length La of the first wire 124a is preferably 1.0% or more and 55% or less. When this ratio is 1.0% or more, the first layer 120 can contribute to torque transmissibility. From this viewpoint, this ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. When this ratio is 55% or less, the hollow stranded wire 118 has excellent flexibility. From this viewpoint, this ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0069] As is clear from Figs. 18 and 19, in the second layer 122 as well, the positions of two adjacent second wires 126 overlap in the axial direction X of the hollow stranded wire 118. The side surfaces of the second wires 126 come into contact with the side surfaces of the other second wires 126. In the second layer 122, when the hollow stranded wire 118 is rotated, a force is sufficiently transmitted between the second wires 126 and the adjacent second wires 126. In the second layer 122, a time lag in rotation is unlikely to occur. The hollow stranded wire 118 can contribute to the torque transmission of medical devices. In the second layer 122 as well, the ratio of the overlap distance L6 between the second wires 126 and the other second wires 126 to the length La of the second wires 126 is preferably 1.0% or more and 55% or less. This ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. This ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0070] 19, arrow α6 indicates the angle of the side surface of the first wire 124 or the second wire 126 with respect to the radial direction Y of the hollow stranded wire 118. The absolute value of angle α6 is preferably 5° or more. The first layer 120 and the second layer 122, whose absolute value is 5° or more, can contribute to torque transmissibility. From this viewpoint, the absolute value is more preferably 10° or more, and particularly preferably 15° or more. From the viewpoint of flexibility of the hollow stranded wire 118, the absolute value is preferably 45° or less.

[0071] The twist direction of the first wires 124 may be either the "Z direction" or the "S direction". The twist direction of the second wires 126 may be either the "Z direction" or the "S direction". From the viewpoint of uniform torque transmissibility, it is preferable that the twist direction of the second wires 126 is opposite to the twist direction of the first wires 124.

[0072] [Seventh embodiment] 20 and 21 show a hollow stranded wire 136 according to yet another embodiment. The hollow stranded wire 136 has a first layer 138, a second layer 140, and a third layer 142. The second layer 140 is located outside the first layer 138. The third layer 142 is located outside the second layer 140. The first layer 138 is formed by twisting a plurality of first strands 144. The second layer 140 is formed by twisting a plurality of second strands 146. The third layer 142 is formed by twisting a plurality of third strands 148. The configurations of the first layer 138 and the second layer 140 are the same as those of the first layer 4 and the second layer 6 shown in FIG. 1-4, respectively. The cross-sectional shape of each third strand 148 is the same as that of the first strand 144 or the second strand 146.

[0073] 22 shows a front third strand 148a and a rear third strand 148b. The distance from the axis line CL (see FIG. 20) to the third strand 148b is equal to the distance from the axis line CL to the third strand 148a. Each third strand 148 has an inner surface 150, an outer surface 152, a front side surface 154, and a rear side surface 156. In the cross section of FIG. 22, the outer surface 152 is generally parallel to the inner surface 150. Furthermore, the rear side surface 156 is generally parallel to the front side surface 154.

[0074] In each of the third strands 148, the inner surface 150 is parallel to the axial direction X of the hollow stranded wire 136, and the outer surface 152 is also parallel to the axial direction X. In this third strand 148, the front side surface 154 is inclined to the radial direction Y of the hollow stranded wire 136, and the rear side surface 156 is also inclined to the radial direction Y. The inclination direction of the front side surface 154 or the rear side surface 156 is radially inward toward the front. Due to this inclination, the front end 158 of the third strand 148b is located forward of the rear end 160 of the third strand 148a. In other words, in the axial direction X of the hollow stranded wire 136, the position of the third strand 148a and the position of the third strand 148b overlap. The front side surface 154 of the third strand 148b abuts against the rear side surface 156 of the third strand 148a. A front side surface 154 of the third wire 148b contacts a rear side surface 156 of the third wire 148a over a large area.

[0075] In the third layer 142, when the hollow stranded wire 136 is rotated, force is sufficiently transmitted between the third wires 148 and the adjacent third wires 148. A rotation time lag is unlikely to occur in the third layer 142. The hollow stranded wire 136 can contribute to the torque transmissibility of the medical device.

[0076] In Fig. 22, arrow L7 indicates the overlap distance between the position of the front third wire 148a and the position of the rear third wire 148b in the axial direction of the hollow stranded wire 136. The ratio of this overlap distance L7 to the length La of the third wire 148 is preferably 1.0% or more and 55% or less. The third layer 142 having this ratio of 1.0% or more can contribute to torque transmissibility. From this viewpoint, this ratio is more preferably 2.0% or more, and particularly preferably 3.0% or more. The hollow stranded wire 136 having this ratio of 55% or less has excellent flexibility. From this viewpoint, this ratio is more preferably 40% or less, and particularly preferably 30% or less.

[0077] In FIG. 22, the arrow α7 indicates the angle of the front side surface 154 with respect to the radial direction Y of the hollow stranded wire 136. As described above, the rear side surface 156 is parallel to the front side surface 154. Therefore, the angle α7 is also the angle of the rear side surface 156 with respect to the radial direction Y of the hollow stranded wire 136. The angle of the rear side surface 156 may be slightly different from the angle α7. The absolute value of the angle α7 is preferably 5° or more. The third layer 142 having an absolute value of 5° or more can contribute to torque transmissibility. From this viewpoint, the absolute value is more preferably 10° or more, and particularly preferably 15° or more. From the viewpoint of the flexibility of the hollow stranded wire 136, the absolute value is preferably 45° or less.

[0078] In this embodiment, the cross-sectional shape of the second wires 146 is congruent with the cross-sectional shape of the first wires 144, and the cross-sectional shape of the third wires 148 is also congruent with the cross-sectional shape of the first wires 144. The hollow stranded wire 136 may have second wires 146 whose cross-sectional shape is different from the cross-sectional shape of the first wires 144. The hollow stranded wire 136 may have third wires 148 whose cross-sectional shape is different from the cross-sectional shape of the first wires 144.

[0079] As shown in FIG. 20 , the twist direction of the first wires 144 is the “Z direction”, the twist direction of the second wires 146 is the “S direction”, and the twist direction of the third wires 148 is the “Z direction”. The twist direction of the second wires 146 is opposite to the twist direction of the first wires 144, and the twist direction of the third wires 148 is the same as the twist direction of the first wires 144. This hollow stranded wire 136 has excellent torque transmission properties regardless of the rotation direction. The twist direction of the second wires 146 may be the same as the twist direction of the first wires 144. The twist direction of the third wires 148 may be opposite to the twist direction of the first wires 144. The hollow stranded wire 136 may have four or more layers. EXAMPLES

[0080] The effects of the hollow stranded wire according to the examples will be explained below, but the scope of the present specification should not be construed as being limited based on the description of these examples.

[0081] [Experiment 1] [Example 1] A wire was obtained by drawing and rolling the steel material made of SUS304 using a die. The cross-sectional shape of the wire was a parallelogram. Six wires were twisted on a core wire to form a first layer. The twist direction of the first layer was the Z direction. The absolute value of the twist angle of the first layer was 75°. Six wires were twisted on the first layer to form a second layer. The twist direction of the second layer was the S direction. The absolute value of the twist angle of the second layer was 75°. A strand made of these wires was subjected to a post-heat treatment. The strand was cut to a predetermined length. The core was removed from the strand to obtain a hollow strand of Example 1. The outer diameter Dc of the hollow strand was 1.30 mm and the inner diameter Di of the hollow strand was 1.00 mm. Each of the wires in the hollow strand had a cross-sectional shape shown in FIG. 7. The absolute value of the angle α (α1) of the side surface of this wire with respect to the radial direction Y of the hollow strand was 85°.

[0082] [Examples 2-5 and Comparative Example 1] The hollow stranded wires of Examples 2-5 and Comparative Example 1 were obtained in the same manner as in Example 1, except that strands having different shapes were used.

[0083] [Torque transmission] The torque transmissibility is evaluated by the difference between the rotation angle at the base end side and the rotation angle at the tip end side when the base end side of the hollow stranded wire is rotated. As shown in FIG. 23, a rigid pipe 168 having a double spiral portion 162, a first straight portion 164, and a second straight portion 166 is prepared. The diameter of the double spiral portion 162 is 200 mm. A hollow stranded wire 170 is passed through this rigid pipe 168. A rotational force is applied to the base end side 172 of the hollow stranded wire 170 in the direction shown by the arrow A2 in FIG. 23. As a result, the tip side 174 of the hollow stranded wire 170 rotates as shown by the arrow A3. The rotation angles of the base end side 172 and the tip side 174 are measured simultaneously.

[0084] FIG. 24 is a graph showing the results of the rotation tracking measured by the method of FIG. 23. The two-dot chain line in the graph is a straight line indicating that the difference between the rotation angle of the base end side 172 and the rotation angle of the tip end side 174 is zero in the entire measurement angle range (the input rotation angle range from 0° to about 720°). The difference between the rotation angle of the base end side 172 and the rotation angle of the tip end side 174 of the hollow stranded wire 170 being measured is represented as the difference in the vertical axis direction between the two-dot chain line in the figure and the measurement value curve. The maximum value of the rotation angle difference measured in the input rotation angle range from 0° to 720° is a value that correlates with torque transmissibility. The maximum value of the angle difference of the hollow stranded wire 170 is shown as an index in Tables 1 and 2 below. A hollow stranded wire with a small index has excellent torque transmissibility.

[0085] [Pushability] As shown in Fig. 25, the vicinity of a first end 178 of a hollow strand 176 was fixed by a chuck 180. The distance from this chuck 180 to a second end 182 of the hollow strand 176 was 100 mm. The hollow strand 176 curved under its own weight, and the second end 182 moved downward. This movement distance L was measured. This movement distance L is shown as an index in Tables 1 and 2 below. A hollow strand 176 with a small index has high rigidity. A hollow strand 176 with a small index has excellent pushability.

[0086] [Table 1]

[0087] [Table 2]

[0088] As shown in Tables 1 and 2, the hollow stranded wires of the respective Examples are excellent in rotational followability and pushability. From these evaluation results, the superiority of the present invention is clear.

[0089] [Experiment 2] [Example 6] The steel material, made of SUS304, was subjected to wire drawing using a special die and rolling to obtain a strand. The cross-sectional shape of this strand was a parallelogram. Eight strands were twisted on a core wire to form a first layer. The twist direction of this first layer was the Z direction. The absolute value of the twist angle of this first layer was 67°. Eight strands were twisted on this first layer to form a second layer. The twist direction of this second layer was the S direction. The absolute value of the twist angle of this second layer was 67°. Eight strands were twisted on this second layer to form a third layer. The twist direction of this third layer was the Z direction. The absolute value of the twist angle of this third layer was 67°. A strand made of these strands was subjected to post-heat treatment. This strand was cut to a predetermined length. The core was removed from this strand to obtain a hollow strand of Example 3. The hollow strand had an outer diameter Dc of 1.77 mm and an inner diameter Di of 1.50 mm. Each strand of the hollow strand had a cross-sectional shape shown in Fig. 7. The absolute value of the angle α (α1) of the side surface of this strand with respect to the radial direction Y of the hollow strand was 85°.

[0090] [Example 7 and Comparative Example 2] The hollow stranded wires of Example 7 and Comparative Example 2 were obtained in the same manner as in Example 1, except that wires having different shapes were used.

[0091] [Torque transmission] The torque transmission properties of the hollow stranded wire were evaluated in the same manner as in Experiment 1. The results are shown in Table 3 below.

[0092] [Pushability] The pushability of the hollow stranded wire was evaluated in the same manner as in Experiment 1. The results are shown in Table 3 below.

[0093] [Table 3]

[0094] As shown in Table 3, the hollow stranded wires of the respective Examples are excellent in rotational followability and pushability. From these evaluation results, the superiority of the present invention is clear.

[0095] [Disclosure items] Each of the following sections discloses a preferred embodiment.

[0096] [Item 1] a first layer formed by twisting three or more first wires; A hollow stranded wire including a second layer formed by twisting three or more second wires and positioned on the outside or inside of the first layer, Each of the first strands has an inner surface, an outer surface, a front side surface, and a rear side surface; The front side surface or the rear side surface is inclined with respect to a radial direction of the hollow strand, A hollow strand in which the front side surface of the rear first wire abuts the rear side surface of the front first wire.

[0097] [Item 2] 2. The hollow strand according to claim 1, wherein the inner surface and the outer surface are parallel to an axial direction of the hollow strand.

[0098] [Item 3] 3. The hollow strand according to item 1 or 2, wherein an angle of the front side surface or the rear side surface with respect to a radial direction of the hollow strand is 5° or more.

[0099] [Item 4] Each second strand has an inner surface, an outer surface, a front side surface, and a rear side surface; The front side surface or the rear side surface is inclined with respect to a radial direction of the hollow strand, 4. The hollow strand according to any one of items 1 to 3, wherein a front side surface of the rear second strand abuts a rear side surface of the front second strand.

[0100] [Item 5] 5. The hollow strand according to item 4, wherein the inner surface and the outer surface of the second wire are parallel to an axial direction of the hollow strand.

[0101] [Item 6] 6. The hollow strand according to item 4 or 5, wherein an angle of the front side surface or the rear side surface of the second strand with respect to a radial direction of the hollow strand is 5° or more.

[0102] [Item 7] 7. The hollow strand according to any one of items 4 to 6, wherein a direction of inclination of the front side surface or the rear side surface of the second strand is opposite to a direction of inclination of the front side surface or the rear side surface of the first strand.

[0103] [Item 8] 8. The hollow stranded wire according to any one of items 1 to 7, wherein the second wires are twisted in a direction opposite to the direction in which the first wires are twisted.

[0104] [Item 9] 9. The hollow strand according to any one of items 1 to 8, wherein the first strands have a twist angle of 85° or less, and the second strands have a twist angle of 85° or less.

[0105] [Item 10] 10. The hollow stranded wire according to any one of items 1 to 9, further comprising a third layer formed by twisting three or more third wires and positioned on the outside or inside of the first layer and the second layer.

[0106] [Item 11] Each third strand has an inner surface, an outer surface, a front side surface, and a rear side surface; The front side surface or the rear side surface is inclined with respect to a radial direction of the hollow strand, Item 11. The hollow strand according to item 10, wherein a rear side surface of the front third strand abuts against a front side surface of the rear third strand.

[0107] [Item 12] the second layer is positioned outside the first layer, the third layer is positioned outside the second layer, The second wire is twisted in a direction opposite to the direction of twist of the first wire, Item 12. The hollow strand according to item 10 or 11, wherein the third wires are twisted in the same direction as the first wires. [Industrial Applicability]

[0108] The hollow stranded wire described above is suitable for various medical devices. This hollow stranded wire is also suitable for applications other than medical devices. [Explanation of symbols]

[0109] 2...Hollow stranded wire 4...First layer 6...Second layer 10...first strand 10a: First front wire 10b: Rear first wire 12...Second wire 12a: Second front wire 12b: Rear second wire 14. Inner surface 16. Outer surface 18 Front side surface 20 Rear side surface 26...Hollow stranded wire 28...first layer 30...Second layer 32...first strand 34...Second wire 34a: Second front wire 34b: Rear second wire 36 Inner surface 38 Outer surface 40···Front side surface 42 Rear side surface 48...Hollow stranded wire 50...first layer 52...Second layer 54...first strand 56...Second wire 58 Bottom Surface 60···Top Surface 62 Front side surface 64 Rear side surface 66...Hollow stranded wire 68...first layer 70...Second layer 72...first strand 74...Second wire 92...Hollow stranded wire 94...first layer 96...Second layer 98...first strand 100...Second strand 118...Hollow stranded wire 120...first layer 122...Second layer 124...first strand 126...Second wire 136...Hollow stranded wire 138...first layer 140...Second layer 142...Third layer 144...first strand 146...Second strand 148...Third wire

Claims

1. a first layer formed by twisting three or more first wires; A hollow stranded wire including a second layer formed by twisting three or more second wires and positioned on the outside or inside of the first layer, Each of the first strands has an inner surface, an outer surface, a front side surface, and a rear side surface; The front side surface or the rear side surface is inclined with respect to a radial direction of the hollow strand, A hollow strand in which the front side surface of the rear first wire abuts the rear side surface of the front first wire.

2. 2. The hollow strand of claim 1, wherein the inner surface and the outer surface are parallel to an axial direction of the hollow strand.

3. 3. The hollow strand according to claim 1, wherein the front side surface or the rear side surface forms an angle of 5 degrees or more with respect to a radial direction of the hollow strand.

4. Each second strand has an inner surface, an outer surface, a front side surface, and a rear side surface; The front side surface or the rear side surface is inclined with respect to a radial direction of the hollow strand, 3. The hollow strand according to claim 1 or 2, wherein a front side surface of the rear second strand abuts against a rear side surface of the front second strand.

5. The hollow strand of claim 4 , wherein the inner surface and the outer surface of the second strand are parallel to an axial direction of the hollow strand.

6. 5. The hollow strand according to claim 4, wherein an angle of the front side surface or the rear side surface of the second strand with respect to a radial direction of the hollow strand is 5 degrees or more.

7. 5. The hollow strand according to claim 4, wherein a direction of inclination of the front side surface or the rear side surface of the second strand is opposite to a direction of inclination of the front side surface or the rear side surface of the first strand.

8. 3. The hollow strand according to claim 1, wherein the second wires are twisted in a direction opposite to the direction in which the first wires are twisted.

9. 3. The hollow stranded wire according to claim 1, wherein the first strands have a twist angle of 85° or less, and the second strands have a twist angle of 85° or less.

10. 3. The hollow stranded wire according to claim 1 or 2, further comprising a third layer formed by twisting three or more third wires and positioned on the outside or inside of the first layer and the second layer.

11. Each third strand has an inner surface, an outer surface, a front side surface, and a rear side surface; The front side surface or the rear side surface is inclined with respect to a radial direction of the hollow strand, 11. The hollow strand according to claim 10, wherein a front side surface of the rear third strand position abuts a rear side surface of the front third strand position.

12. the second layer is positioned outside the first layer, the third layer is positioned outside the second layer, The second wire is twisted in a direction opposite to the direction of twist of the first wire, The hollow strand according to claim 10 , wherein the third strands are twisted in the same direction as the first strands.

Images