Flexible drive shaft

Abstract

To provide a flexible drive shaft 2 that can stably rotate in a device.SOLUTION: The flexible drive shaft 2 comprises a main shaft 4, a plurality of retainers 6, and a plurality of rotors 8. The main shaft 4 comprises a first coil 10 and a second coil 12. Each of the retainers 6 is fixed to the main shaft 4. Each of the rotors 8 is attached to the main shaft 4 via the retainers 6. The rotors 8 wholly protrude from an outer peripheral surface of the main shaft 4. The rotors 8 have a spherical shape. The rotors 8 are partially exposed from the retainers 6. The rotors 8 can rotate with respect to the retainers 6.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present specification discloses a flexible drive shaft that can be included in a medical device or the like used for examining or treating a living body. [Background technology]

[0002] An intravascular ultrasound catheter has a sheath, a hollow flexible drive shaft passed through the sheath, a cable passed through the drive shaft, a transducer fixed to the tip of the drive shaft, and a drive (motor) fixed to the base end of the drive shaft. The drive shaft is rotated by the driving force of the motor, and the rotation of the drive shaft rotates the transducer. The transducer rotates while moving backward within the blood vessel. The transducer emits an ultrasound signal and receives a reflected signal of this ultrasound signal. This reflected signal is transmitted by the cable. Continuous images of the blood vessel cross section are obtained from this reflected signal. An example of an intravascular ultrasound catheter is disclosed in JP 2017-515600 A. This catheter includes a drive shaft with a lubricating coating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special publication 2017-515600 Summary of the Invention [Problem to be solved by the invention]

[0004] The sheath and drive shaft bend inside the blood vessel. This bending causes localized friction between the inner surface of the sheath and the drive shaft in the catheter. This friction causes variations in the rotational speed of the tip of the drive shaft and the transducer, and promotes vibration of the rotation axis. This friction can lead to a decrease in the resolution of the acquired image and an increase in positional error of the acquired image (the difference between the positional information of the tissue slice being acquired and the acquired image).

[0005] Variations in the rotational speed of a flexible drive shaft due to local friction also occur in various medical devices other than catheters. Variations in rotational speed also occur in devices other than medical devices.

[0006] It is the applicant's intention to provide a flexible drive shaft that can rotate stably in a device. [Means for solving the problem]

[0007] The flexible drive shaft disclosed in this specification is Hollow main shaft and Multiple rotors attached to this main shaft Each rotor protrudes from the outer circumferential surface of the main shaft. [Effects of the Invention]

[0008] In this flexible drive shaft, the rotor reduces friction between the drive shaft and other components, making it less susceptible to variations in rotational speed caused by friction. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view showing a portion of a flexible drive shaft according to one embodiment. [Figure 2] FIG. 2 is an enlarged view of a portion of the flexible drive shaft of FIG. [Figure 3] FIG. 3 is an exploded cross-sectional view taken along line III-III in FIG. [Figure 4] 4 is an enlarged perspective view showing a retainer and a rotor of the flexible drive shaft of FIG. 1. FIG. [Figure 5] FIG. 5 is an enlarged cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a front view showing a part of a flexible drive shaft according to another embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a portion of a flexible drive shaft according to yet another embodiment. [Figure 8] FIG. 8 is a front view showing a portion of a flexible drive shaft according to yet another embodiment. [Figure 9] FIG. 9 is an enlarged view of a portion of the flexible drive shaft of FIG. [Figure 10] 10 is an enlarged perspective view showing the retainer and rotor of the flexible drive shaft of FIG. 8. FIG. [Figure 11] FIG. 11 is an enlarged cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a front view showing a portion of a flexible drive shaft according to yet another embodiment. [Figure 13] FIG. 13 is an enlarged cross-sectional view taken along line XIII-XIII in FIG. [Figure 14] 14 is an exploded perspective view showing a retainer and a rotor of the flexible drive shaft of FIG. 12. FIG. [Figure 15] FIG. 15 is a front view showing a portion of a flexible drive shaft according to yet another embodiment. [Figure 16] FIG. 16 is an enlarged cross-sectional view taken along line XVI-XVI in FIG. [Figure 17] 17 is a perspective view of a portion of the material of the flexible drive shaft of FIG. 15. FIG. [Figure 18]FIG. 18 is an exploded cross-sectional view taken along line XVIII-XVIII in FIG. [Figure 19] FIG. 19 is a front view showing a portion of a flexible drive shaft according to yet another embodiment. [Figure 20] FIG. 20 is an exploded cross-sectional view showing the flexible drive shaft of FIG. [Figure 21] FIG. 21 is a front view showing a portion of a flexible drive shaft according to yet another embodiment. [Figure 22] FIG. 22 is an enlarged view showing the retainer, rotor, and sub-rotor of the flexible drive shaft of FIG. [Figure 23] FIG. 23 is a cross-sectional view taken along line XXIII-XXIII in FIG. [Figure 24] FIG. 24 is a cross-sectional view taken along line XXIV-XXIV in FIG. [Figure 25] 25 is a perspective view showing the body of the retainer of FIG. 22. FIG. [Figure 26] FIG. 26 is an enlarged view showing the rotor and sub-rotor of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred embodiments will be described in detail with reference to the drawings as appropriate.

[0011] [First embodiment] 1-3 show a flexible drive shaft 2. This drive shaft 2 has a main shaft 4, multiple retainers 6, and multiple rotors 8. In FIGS. 1 and 2, the right side is the tip end of the drive shaft 2, and the left side is the base end of the drive shaft 2.

[0012] As shown in Figures 2 and 3, the main shaft 4 has a first coil 10 and a second coil 12. The number of coils is two. The second coil 12 is located outside the first coil 10. As shown in Figure 3, the inner circumferential surface of the second coil 12 abuts against the outer circumferential surface of the first coil 10. The main shaft 4 is hollow.

[0013] The first coil 10 has a plurality of first wires 14. The first coil 10 can be formed by coiling a plurality of straight first wires 14. As is clear from FIG. 3 , in this embodiment, the number of first wires 14 is six. The number of first wires 14 may be five or less, or seven or more. Each first wire 14 is wound clockwise toward the right in FIG. 2 . As is clear from FIG. 3 , the cross-sectional shape of this first wire 14 is non-circular. This cross-sectional shape is generally oval.

[0014] The first coil 10 has a plurality of first gaps 16. Each first gap 16 is located between one first wire 14 and another adjacent first wire 14. The first gaps 16 extend from the outer circumferential surface to the inner circumferential surface of the first coil 10. The first gaps 16 are inclined with respect to the axial direction of the main shaft 4. In other words, the absolute value of the angle of the first gaps 16 with respect to the axial direction is greater than 0° and equal to or less than 90°. The first gaps 16 can contribute to the flexibility of the first coil 10.

[0015] The second coil 12 has a plurality of second wires 18. The second coil 12 can be formed by coiling a plurality of straight second wires 18. As is clear from FIG. 3 , in this embodiment, the number of second wires 18 is six. The number of second wires 18 may be five or less, or seven or more. Each second wire 18 is wound counterclockwise toward the right in FIG. 2 . In other words, the winding direction of the second wires 18 is opposite to the winding direction of the first wires 14. As is clear from FIG. 3 , the cross-sectional shape of this second wire 18 is non-circular. This cross-sectional shape is generally oval.

[0016] The second coil 12 has a plurality of second gaps 20. Each second gap 20 is located between one second wire 18 and another adjacent second wire 18. The second gaps 20 extend from the outer circumferential surface to the inner circumferential surface of the second coil 12. The second gaps 20 are inclined with respect to the axial direction of the main shaft 4. In other words, the absolute value of the angle of the second gaps 20 with respect to the axial direction is greater than 0° and equal to or less than 90°. The second gaps 20 can contribute to the flexibility of the second coil 12.

[0017] When the main shaft 4 rotates counterclockwise due to torque at the base end, a rotational time lag is unlikely to occur in the first coil 10. The first coil 10 can contribute to stabilizing the rotational speed when the main shaft 4 rotates counterclockwise. When the main shaft 4 rotates clockwise due to torque at the base end, a rotational time lag is unlikely to occur in the second coil 12. The second coil 12 can contribute to stabilizing the rotational speed when the main shaft 4 rotates clockwise. The main shaft 4 is unlikely to experience variations in rotational speed regardless of the rotation direction.

[0018] The main shaft 4 may have three or more coils. The main shaft 4 may have a shape other than a coil. An example of the main shaft 4 having a shape other than a coil is a hypotube.

[0019] In this embodiment, the main shaft 4 is made of a metal material. From the viewpoint of strength and corrosion resistance, a preferred metal material is stainless steel.

[0020] Each rotor 8 is attached to the main shaft 4 via a retainer 6, which will be described in detail later. The rotor 8 is located radially outward of the main shaft 4. In other words, the rotor 8 as a whole protrudes from the outer circumferential surface of the main shaft 4. The rotor 8 has a spherical shape. The rotor 8 may also have a disk shape.

[0021] In this embodiment, the rotor 8 is made of a metal material. From the viewpoint of strength and corrosion resistance, a preferred metal material is stainless steel.

[0022] As is clear from Fig. 1, each retainer 6 is spaced apart from the other retainers 6 in the axial direction of the main shaft 4. As shown in Figs. 3 and 4, each retainer 6 has a lower cylinder 22, a base 24, and an upper cylinder 26.

[0023] The lower cylinder 22 has a notch 28. In this embodiment, the contour of the notch 28 is roughly semicircular. The notch 28 abuts against the main shaft 4 (see also FIG. 2). The notch 28 is joined to the second coil 12 by means of welding, brazing, or the like. The retainer 6 is fixed to the main shaft 4 by this joining.

[0024] The base 24 is located between the lower cylinder 22 and the upper cylinder 26. The base 24 is annular. The inner diameter of the base 24 is smaller than the inner diameter of the upper cylinder 26. Furthermore, the inner diameter of the base 24 is smaller than the outer diameter of the rotor 8.

[0025] The upper cylinder 26 has a retainer 30. The retainer 30 has an annular shape. The inner diameter of the retainer 30 is smaller than the outer diameter of the rotor 8.

[0026] As shown in FIG. 3 , the rotor 8 is sandwiched between the base 24 and the retainer 30. In other words, the retainer 6 holds the rotor 8. The rotor 8 can rotate relative to the retainer 6. A portion of the rotor 8 is exposed from the retainer 6. As described above, the retainer 6 is fixed to the main shaft 4. The rotor 8 is attached to the main shaft 4 via the retainer 6. The position of the rotor 8 in the axial and circumferential directions of the flexible drive shaft 2 is fixed. The retainer 6 can have various structures that can rotatably hold the rotor 8 and can be fixed to the main shaft 4.

[0027] FIG. 5 shows two rotors 8. Specifically, FIG. 5 shows a first rotor 8a and a second rotor 8b. As is clear from FIGS. 1 and 5, the first rotor 8a protrudes upward relative to the main shaft 4. The second rotor 8b protrudes downward relative to the main shaft 4. The protruding direction of the second rotor 8b in the circumferential direction of the main shaft 4 is different from the protruding direction of the first rotor 8a. In this embodiment, the angle between the protruding direction of the second rotor 8b and the protruding direction of the first rotor 8a in the circumferential direction of the main shaft 4 is 180°. The specifications of the second rotor 8b, except for the protruding direction, are the same as those of the first rotor 8a.

[0028] In an intravascular ultrasound catheter, a flexible drive shaft 2 is passed through a sheath. In this catheter, a rotor 8 abuts the inner surface of the sheath. Even if the sheath is bent inside the blood vessel, the rotor 8 rotates, allowing the drive shaft 2 to maintain a posture with minimal curvature. Even if the sheath is twisted inside the blood vessel, the rotor 8 rotates, allowing the drive shaft 2 to maintain a posture with minimal twisting. This drive shaft 2 can prevent damage to cables, fibers, etc. passed through it.

[0029] A drive such as a motor is attached to the base of the flexible drive shaft 2. When the drive shaft 2 rotates relative to the sheath, the motor causes the rotor 8 to rotate relative to the retainer 6. The rotation of the rotor 8 reduces the frictional force of the drive shaft 2 relative to the sheath. The rotor 8 enables smooth rotation of the drive shaft 2 relative to the sheath. Even if the sheath is bent or twisted inside the blood vessel, the variation in the rotational speed of the drive shaft 2 is small. This drive shaft 2 can contribute to highly accurate examinations.

[0030] In FIG. 1, arrow Dd represents the apparent outer diameter of flexible drive shaft 2, and arrow Dm represents the outer diameter of main shaft 4. The apparent outer diameter Dd is also shown in FIG. 5. From the viewpoint of suppressing contact between main shaft 4 and the inner surface of the sheath, the apparent outer diameter Dd is preferably 1.2 times or more, more preferably 1.5 times or more, and particularly preferably 1.7 times or more, of the outer diameter Dm. From the viewpoint of compactness of drive shaft 2, the apparent outer diameter Dd is preferably 5.0 times or less, more preferably 3.7 times or less, and particularly preferably 3.5 times or less, of the outer diameter Dm. The apparent outer diameter Dd is the diameter of the smallest circle that can contain the entire drive shaft 2 within its outline in the cross section of FIG. 5.

[0031] 2, the arrow Hi indicates the protruding height of the rotor 8 from the main shaft 4. From the viewpoint of suppressing contact between the main shaft 4 and the inner surface of the sheath, this height Hi is preferably 0.10 mm or more, more preferably 0.20 mm or more, and particularly preferably 0.25 mm or more. From the viewpoint of achieving a sufficiently small apparent outer diameter Do, this height Hi is preferably 3.0 mm or less, more preferably 2.0 mm or less, and particularly preferably 1.5 mm or less.

[0032] 3, arrow Do represents the outer diameter of main shaft 4, and arrow Di represents the inner diameter of main shaft 4. From the viewpoint of stabilizing the rotational speed and the rotation axis of drive shaft 2, the outer diameter Do is preferably 6.0 mm or less, more preferably 4.0 mm or less, and particularly preferably 2.0 mm or less. From the viewpoint of facilitating the passage of cables, fibers, etc. through main shaft 4, the inner diameter Di is preferably 0.15 mm or more, more preferably 0.5 mm or more, and particularly preferably 1.0 mm or more.

[0033] [Second embodiment] Figure 6 shows a flexible drive shaft 32 according to another embodiment. The drive shaft 32 has a main shaft 34, multiple retainers 36, and multiple rotors 38. The main shaft 34 has a first coil 40, a second coil 42, and a third coil 44. The number of coils is three. The second coil 42 is located outside the first coil 40. The third coil 44 is located outside the second coil 42. The main shaft 34 is hollow. The configuration of the drive shaft 32, other than the main shaft 34, is the same as that of the drive shaft 2 shown in Figures 1-5.

[0034] The first coil 40 has a plurality of first wires 46. The first coil 40 can be formed by coiling a plurality of straight first wires 46. Each of the first wires 46 is wound counterclockwise toward the right in FIG. 6. The first coil 40 has a plurality of first gaps 48. Each of the first gaps 48 extends from the outer circumferential surface to the inner circumferential surface of the first coil 40. The first gaps 48 are inclined with respect to the axial direction of the main shaft 34.

[0035] The second coil 42 has a plurality of second wires 50. The second coil 42 can be formed by coiling a plurality of straight second wires 50. Each second wire 50 is wound clockwise toward the right in FIG. 6. In other words, the winding direction of the second wires 50 is opposite to the winding direction of the first wires 46. The second coil 42 has a plurality of second gaps 52. Each second gap 52 extends from the outer circumferential surface to the inner circumferential surface of the second coil 42. The second gaps 52 are inclined with respect to the axial direction of the main shaft 34.

[0036] The third coil 44 has a plurality of third wires 54. The third coil 44 can be formed by coiling a plurality of straight third wires 54. Each third wire 54 is wound counterclockwise toward the right in FIG. 6. In other words, the winding direction of the third wires 54 is opposite to the winding direction of the second wires 50. The third coil 44 has a plurality of third gaps 56. Each third gap 56 extends from the outer circumferential surface to the inner circumferential surface of the third coil 44. The third gaps 56 are inclined with respect to the axial direction of the main shaft 34. A retainer 36 is fixed to the third coil 44.

[0037] When the main shaft 34 rotates clockwise due to torque at the base end, a rotational time lag is unlikely to occur in the first coil 40 and the third coil 44. The first coil 40 and the third coil 44 can contribute to stabilizing the rotational speed when the main shaft 34 rotates clockwise. When the main shaft 34 rotates counterclockwise due to torque at the base end, a rotational time lag is unlikely to occur in the second coil 42. The second coil 42 can contribute to stabilizing the rotational speed when the main shaft 34 rotates counterclockwise. The main shaft 34 is unlikely to experience variations in rotational speed regardless of the rotation direction.

[0038] The main shaft 34 may have four or more coils.

[0039] [Third embodiment] 7 is a cross-sectional view showing a portion of a flexible drive shaft 58 according to yet another embodiment. The drive shaft 58 has a main shaft 60, a plurality of retainers 62, and a plurality of rotors 64.

[0040] FIG. 7 shows a first rotor 64a, a second rotor 64b, and a third rotor 64c. The first rotor 64a protrudes upward relative to the main shaft 60. The second rotor 64b protrudes diagonally downward to the right relative to the main shaft 60. In the circumferential direction of the main shaft 60, the protruding direction of the second rotor 64b differs from the protruding direction of the first rotor 64a. The third rotor 64c protrudes diagonally downward to the left relative to the main shaft 60. In the circumferential direction of the main shaft 60, the protruding direction of the third rotor 64c differs from the protruding direction of the first rotor 64a and also differs from the protruding direction of the second rotor 64b. The angle between the protruding direction of the second rotor 64b and the protruding direction of the first rotor 64a is 120°. The angle between the protruding direction of the third rotor 64c and the protruding direction of the second rotor 64b is 120°. On this drive shaft 58, multiple rotors 64 are arranged at 120° intervals. The specifications of the second rotor 64b, except for the protruding direction, are the same as those of the first rotor 64a. The specifications of the third rotor 64c, except for the protruding direction, are the same as those of the first rotor 64a.

[0041] The specifications of this drive shaft 58 are the same as those of the drive shaft 2 shown in Figures 1-5, except for the protruding direction of the rotor 64 and the retainer 62. The rotor 64 is attached to the main shaft 60 via the retainer 62. The rotor 64 entirely protrudes from the outer circumferential surface of the main shaft 60. The rotor 64 can rotate relative to the retainer 62. This rotation reduces the frictional force of the drive shaft 58 against the sheath, etc. The drive shaft 58 may have the main shaft 34 shown in Figure 6.

[0042] In this flexible drive shaft 58, the apparent outer diameter Dd is preferably at least 1.2 times, more preferably at least 1.5 times, and particularly preferably at least 1.7 times the outer diameter Dm of the main shaft 60. The apparent outer diameter Dd is preferably no more than 5.0 times, more preferably no more than 3.7 times, and particularly preferably no more than 3.5 times the outer diameter Dm.

[0043] In this flexible drive shaft 58, the protruding height of the rotor 64 from the main shaft 60 is preferably 0.10 mm or more, more preferably 0.20 mm or more, and particularly preferably 0.25 mm or more. This height is preferably 3.0 mm or less, more preferably 2.0 mm or less, and particularly preferably 1.5 mm or less.

[0044] The flexible drive shaft 58 may have multiple rotors 64 arranged at 90° intervals. The drive shaft 58 may have multiple rotors 64 arranged at 72° intervals. The drive shaft 58 may have multiple rotors 64 arranged at 60° intervals. The drive shaft 58 may have multiple rotors 64 arranged at 45° intervals. The drive shaft 58 may have multiple rotors 64 arranged at 40° intervals. The drive shaft 58 may have multiple rotors 64 arranged at 36° intervals. The drive shaft 58 may have multiple rotors 64 arranged at 30° intervals. The drive shaft 58 may have multiple rotors 64 arranged randomly in the circumferential direction.

[0045] [Fourth embodiment] 8-11 show yet another embodiment of a flexible drive shaft 66. The drive shaft 66 includes a main shaft 68, a plurality of retainers 70, and a plurality of rotors 72.

[0046] As shown in Figures 10 and 11, each retainer 70 has a lower cylinder 74, a base 76, and an upper cylinder 78. Comparing Figure 11 with Figure 3 makes it clear that the axial length of the lower cylinder 74 is longer than that of the lower cylinder 22 shown in Figure 3. The lower cylinder 74 has a hole 80 through which the main shaft 68 passes. The hole 80 is joined to the main shaft 68 by welding, brazing, or other means. This joining secures the retainer 70 to the main shaft 68. Except for the configuration of the lower cylinder 74, the specifications of the drive shaft 66 are the same as those of the drive shaft 2 shown in Figures 1-5. The rotor 72 is attached to the main shaft 68 via the retainer 70. The rotor 72 generally protrudes from the outer circumferential surface of the main shaft 68. The rotor 72 is rotatable relative to the retainer 70. This rotation reduces friction between the drive shaft 66 and the sheath, etc. The drive shaft 66 may include the main shaft 34 shown in FIG.

[0047] In this flexible drive shaft 66, the apparent outer diameter Dd is preferably at least 1.2 times, more preferably at least 1.5 times, and particularly preferably at least 1.7 times the outer diameter Dm of the main shaft 68. The apparent outer diameter Dd is preferably no more than 5.0 times, more preferably no more than 3.7 times, and particularly preferably no more than 3.5 times the outer diameter Dm.

[0048] In this flexible drive shaft 66, the protruding height of the rotor 72 from the main shaft 68 is preferably 0.10 mm or more, more preferably 0.20 mm or more, and particularly preferably 0.25 mm or more. This height is preferably 3.0 mm or less, more preferably 2.0 mm or less, and particularly preferably 1.5 mm or less.

[0049] [Fifth embodiment] 12 and 13 show a flexible drive shaft 82 according to yet another embodiment. This drive shaft 82 has a main shaft 84, a plurality of retainers 86, and a plurality of rotors 88. The configuration of the main shaft 84 is the same as that of the main shaft 4 shown in FIGS. 2 and 3. Each retainer 86 is spaced apart from the other retainers 86 in the axial direction of the main shaft 84.

[0050] As shown in Figure 14, the retainer 86 has a body 90 and a pair of side plates 92. The body 90 has a hole 94 and a pair of chambers 96. The side plates 92 have a hole 93. As shown in Figure 13, the main shaft 84 passes through the hole 94. This hole 94 is joined to the main shaft 84 by means of welding, brazing, or the like. The retainer 86 is fixed to the main shaft 84 by this joining.

[0051] Each chamber 96 is open to the outside. The chamber 96 has an undercut shape. A plurality of rotors 88 are housed in the chamber 96. In the present embodiment, each chamber 96 houses four rotors 88. Each rotor 88 has a spherical shape. A portion of the rotor 88 is exposed from the retainer 86. Since the rotor 88 is sandwiched between a pair of side plates 92, the position of the rotor 88 in the axial and circumferential directions of the flexible drive shaft 82 is fixed. The rotors 88 are attached to the main shaft 84 via the retainer 86. The chamber 96 may have a shape that allows the rotors 88 to be spaced apart from adjacent rotors 88.

[0052] The rotor 88 generally protrudes from the outer circumferential surface of the main shaft 84. The direction in which the rotor 88 housed in one chamber 96 protrudes is different from the direction in which the rotor 88 housed in the other chamber 96 protrudes. The rotor 88 can rotate relative to the retainer 86. This rotation reduces the frictional force of the drive shaft 82 against the sheath, etc. The drive shaft 82 may have the main shaft 34 shown in FIG. 6.

[0053] In this flexible drive shaft 82, the apparent outer diameter Dd is preferably at least 1.2 times, more preferably at least 1.5 times, and particularly preferably at least 1.7 times the outer diameter Dm of the main shaft 84. The apparent outer diameter Dd is preferably no more than 5.0 times, more preferably no more than 3.7 times, and particularly preferably no more than 3.5 times the outer diameter Dm.

[0054] In this flexible drive shaft 82, the protruding height of the rotor 88 from the main shaft 84 is preferably 0.10 mm or more, more preferably 0.20 mm or more, and particularly preferably 0.25 mm or more. This height is preferably 3.0 mm or less, more preferably 2.0 mm or less, and particularly preferably 1.5 mm or less.

[0055] [Sixth embodiment] 15 and 16 show a flexible drive shaft 98 according to yet another embodiment. The drive shaft 98 includes a main shaft 100, multiple retainers 102, and multiple rotors 104. The main shaft 100 includes a first coil 106 and a second coil 108. The second coil 108 is located outside the first coil 106. The first coil 106 includes multiple first strands 110. The first coil 106 can be formed by coiling multiple straight first strands 110. The second coil 108 includes multiple second strands 112. The second coil 108 can be formed by coiling multiple straight second strands 112. The second strands 112 include second strands 112a with rails 114, which will be described later, and second strands 112b without rails 114.

[0056] 3 and 4. The retainers 102 are joined to the second wires 112. The retainers 102 are spaced apart from each other in the axial and circumferential directions of the main shaft 100.

[0057] Each rotor 104 has a spherical shape. The rotor 104 is smaller than the rotor 8 shown in Figures 3 and 4. The rotor 104 is held by a retainer 102. The rotor 104 entirely protrudes from the outer circumferential surface of the main shaft 100.

[0058] 16 , the drive shaft 98 has multiple rotors 104 arranged at 90° intervals. The flexible drive shaft 98 may have multiple rotors 104 arranged at 180° intervals, multiple rotors 104 arranged at 120° intervals, multiple rotors 104 arranged at 72° intervals, multiple rotors 104 arranged at 60° intervals, multiple rotors 104 arranged at 45° intervals, multiple rotors 104 arranged at 40° intervals, multiple rotors 104 arranged at 36° intervals, or multiple rotors 104 arranged at 30° intervals. The drive shaft 98 may also have multiple rotors 104 arranged randomly in the circumferential direction.

[0059] 17 and 18 show a straight second wire 112a. This second wire 112 has a base 116 and a rail 114. The rail 114 protrudes from the base 116. The rail 114 is located at the center of the second wire 112 in the width direction. The rail 114 extends along the length of the second wire 112.

[0060] 17 and 18 also show the retainer 102 and the rotor 104. Multiple retainers 102 are positioned spaced apart from one another in the longitudinal direction of the second strand 112. Each retainer 102 has a lower cylinder 118, a base 120, and an upper cylinder 122. The lower cylinder 118 has a notch 124. In this embodiment, the outline of the notch 124 is generally rectangular. This notch 124 fits into the rail 114. The retainer 102 is joined to the second strand 112 by means of welding, brazing, or the like. The base 120 is positioned between the lower cylinder 118 and the upper cylinder 122. This base 120 is annular. The inner diameter of this base 120 is smaller than the inner diameter of the upper cylinder 122. Furthermore, the inner diameter of this base 120 is smaller than the outer diameter of the rotor 104. The upper cylinder 122 has a retainer 126. The retainer 126 is annular in shape. The inner diameter of the retainer 126 is smaller than the outer diameter of the rotor 104. The rotor 104 is sandwiched between the base 120 and the retainer 126.

[0061] The drive shaft 98 shown in FIGS. 17 and 18 can be obtained by coiling the second strands 112a to which the retainers 102 are attached together with the second strands 112b to which the retainers 102 are not attached. Retainers 102 may be attached to all of the second strands 112 to be coiled. Alternatively, multiple second strands 112 to which no retainers 102 are attached may be coiled to obtain the second coil 108, and then the retainers 102 may be attached to the second strands 112a. The second strands 112 to which no retainers 102 are attached may have rails 114.

[0062] In this drive shaft 98, a rotor 104 is attached to a main shaft 100 via a retainer 102. The rotor 104 can rotate relative to the retainer 102. This rotation reduces the frictional force of the drive shaft 98 against the sheath, etc. The drive shaft 98 may have the main shaft 34 shown in FIG. 6.

[0063] The apparent outer diameter Dd of this flexible drive shaft 98 is preferably at least 1.2 times, more preferably at least 1.3 times, and particularly preferably at least 1.5 times the outer diameter Dm of the main shaft 100. The apparent outer diameter Dd is preferably no more than 3.0 times, more preferably no more than 2.5 times, and particularly preferably no more than 2.0 times the outer diameter Dm.

[0064] In this flexible drive shaft 98, the protruding height of the rotor 104 from the main shaft 100 is preferably 0.10 mm or more, more preferably 0.20 mm or more, and particularly preferably 0.25 mm or more. This height is preferably 1.5 mm or less, more preferably 1.0 mm or less, and particularly preferably 0.5 mm or less.

[0065] [Seventh embodiment] FIG. 19 shows a flexible drive shaft 128 according to yet another embodiment. The drive shaft 128 includes a main shaft 130, multiple retainers 132, and multiple rotors 134. The main shaft 130 includes a first coil 136 and a second coil 138. The second coil 138 is located outside the first coil 136. The first coil 136 includes multiple first strands 140. The first coil 136 can be formed by coiling multiple straight first strands 140. The second coil 138 includes multiple second strands 142. The second coil 138 can be formed by coiling multiple straight second strands 142. The second strands 142 include second strands 142a having grooves 144, which will be described later, and second strands 142b without grooves 144.

[0066] 3 and 4. The retainers 132 are joined to the second wires 142a. The retainers 132 are spaced apart from each other in the axial and circumferential directions of the main shaft 130.

[0067] Each rotor 134 has a spherical shape. The rotors 134 are smaller than the rotor 8 shown in Figures 3 and 4. The rotors 134 are held by a retainer 132. The rotors 134 generally protrude from the outer circumferential surface of the main shaft 130.

[0068] 20 shows the second wire 142a. This second wire 142a has a groove 144. The groove 144 is located in the center of the width of the second wire 142a. The groove 144 extends along the length of the second wire 142a.

[0069] FIG. 20 also shows the retainer 132 and the rotor 134. The retainer 132 has a lower cylinder 146, a base 148, and an upper cylinder 150. The lower cylinder 146 has a foot 152. The foot 152 is fitted into the groove 144. The retainer 132 is joined to the second strand 142a by means of welding, brazing, or the like. The base 148 is located between the lower cylinder 146 and the upper cylinder 150. The base 148 is annular. The inner diameter of the base 148 is smaller than the inner diameter of the upper cylinder 150. Furthermore, the inner diameter of the base 148 is smaller than the outer diameter of the rotor 134. The upper cylinder 150 has a presser foot 154. The presser foot 175 is annular in shape. The inner diameter of the presser foot 154 is smaller than the outer diameter of the rotor 134. The rotor 134 is sandwiched between a base 148 and a retainer 154 .

[0070] The drive shaft 128 shown in FIG. 19 can be obtained by coiling the second wire 142a to which the retainer 132 is attached together with the second wire 142b to which the retainer 132 is not attached. Retainers 132 may be attached to all of the second wires 142 to be coiled. Alternatively, multiple second wires 142 to which no retainer 132 is attached may be coiled to obtain the second coil 138, and then the retainer 132 may be attached to the second wire 142a. The second wire 142 to which no retainer 132 is attached may have a groove 144.

[0071] The configuration of this drive shaft 128 is the same as that of the drive shaft 98 shown in FIGS. 15-18 except for the fitting structure between the retainer 132 and the second wire 142. In this drive shaft 128, the rotor 134 is attached to the main shaft 130 via the retainer 132. The rotor 134 can rotate relative to the retainer 132. This rotation reduces the frictional force of the drive shaft 128 against the sheath, etc. The drive shaft 128 may have the main shaft 34 shown in FIG. 6.

[0072] The apparent outer diameter Dd of this flexible drive shaft 128 is preferably at least 1.2 times, more preferably at least 1.3 times, and particularly preferably at least 1.5 times the outer diameter Dm of the main shaft 130. The apparent outer diameter Dd is preferably no more than 3.0 times, more preferably no more than 2.5 times, and particularly preferably no more than 2.0 times the outer diameter Dm.

[0073] In this flexible drive shaft 128, the protruding height of the rotor 134 from the main shaft 130 is preferably 0.10 mm or more, more preferably 0.20 mm or more, and particularly preferably 0.25 mm or more. This height is preferably 1.5 mm or less, more preferably 1.0 mm or less, and particularly preferably 0.5 mm or less.

[0074] [Eighth embodiment] 21 shows a flexible drive shaft 156 according to yet another embodiment. This drive shaft 156 has a main shaft 158, multiple retainers 160, multiple rotors 162, and multiple sub-rotors 164. The configuration of the main shaft 158 ​​is the same as that of the main shaft 4 shown in FIGS. 2 and 3.

[0075] Each retainer 160 is spaced apart from the other retainers 160 in the axial direction of the main shaft 158. As shown in Figures 22 and 23, this retainer 160 has a body 166 and an end cover 168. The end cover 168 is joined to the body 166. The end cover 168 has a hole 170.

[0076] As shown in Figures 24 and 25, the body 166 has a hole 172 and four chambers 174. As shown in Figure 24, the main shaft 158 ​​passes through the hole 172. The retainer 160 is fixed to this main shaft 158. Fixing can be achieved by means of welding, brazing, or the like. The four chambers 174 are arranged at 90° intervals in the circumferential direction.

[0077] Each chamber 174 has a main chamber 176 and a sub-chamber 178. As shown in FIG. 23, in this embodiment, the main chamber 176 houses three rotors 162, and the sub-chamber 178 houses two sub-rotors 164. The circumferential positions of these five rotors 162, 164 are the same. As shown in FIG. 23, each rotor 162 is spaced apart from the other rotors 162 in the axial direction. Each sub-rotor 164 abuts against two rotors 162.

[0078] FIG. 26 shows rotors 162 and sub-rotors 164. When rightmost rotor 162a rotates in the direction indicated by arrow A1, friction with sub-rotor 164a rotates in the direction indicated by arrow A2. Friction with sub-rotor 164a rotates rotor 162b in the direction indicated by arrow A1. Friction with sub-rotor 164b rotates sub-rotor 164b in the direction indicated by arrow A2. Friction with sub-rotor 164b rotates rotor 162c in the direction indicated by arrow A1. In this operating wire, the three rotors 162 can rotate smoothly in the same direction. This rotation reduces the frictional force of drive shaft 156 against the sheath, etc. The drive shaft 156 may have the main shaft 34 shown in FIG. 6.

[0079] In this flexible drive shaft 156, the apparent outer diameter Dd is preferably at least 1.2 times, more preferably at least 1.5 times, and particularly preferably at least 1.7 times the outer diameter Dm of the main shaft 158. The apparent outer diameter Dd is preferably no more than 5.0 times, more preferably no more than 3.7 times, and particularly preferably no more than 3.5 times the outer diameter Dm.

[0080] In this flexible drive shaft 156, the protruding height of the rotor 162 from the main shaft 158 ​​is preferably 0.10 mm or more, more preferably 0.20 mm or more, and particularly preferably 0.25 mm or more. This height is preferably 3.0 mm or less, more preferably 2.0 mm or less, and particularly preferably 1.5 mm or less.

[0081] [Applications of each flexible drive shaft] Each of the flexible drive shafts described above is suitable for various medical devices. This medical device includes a sheath, a flexible drive shaft threaded through the sheath, and a drive fixed to the flexible drive shaft. Examples of medical devices include intravascular devices such as guidewires and catheters, endoscopic devices, and laparoscopic surgery devices such as forceps for laparoscopic surgery. This drive shaft is also suitable for robotic components such as arms and hands. This drive shaft is also suitable for motion assist devices such as power-assisted suits, welfare devices such as prosthetic arms and legs, and nursing care devices such as nursing assistance robots. This drive shaft is also suitable for components such as narrow-path traveling robots, pipeline traveling robots, rescue robots, pipe inspection robots, and underfloor inspection robots.

[0082] [Disclosure items] Each of the following sections discloses a preferred embodiment.

[0083] [Item 1] Hollow main shaft and Multiple rotors attached to this main shaft It is equipped with A flexible drive shaft, wherein each rotor protrudes from the outer circumferential surface of the main shaft.

[0084] [Item 2] Further comprising a plurality of retainers; Each retainer is spaced apart from the other retainers, Item 2. The flexible drive shaft according to item 1, wherein the rotor is attached to the main shaft via the retainer.

[0085] [Item 3] The retainer has a chamber extending along the axial direction of the main wire, The chamber accommodates a first rotor, a second rotor, and a sub-rotor; the second rotor is spaced apart from the first rotor, the sub rotor is located between the first rotor and the second rotor in the axial direction of the main wire, 3. The flexible drive shaft according to item 2, wherein the sub-rotor abuts against the first rotor and also abuts against the second rotor.

[0086] [Item 4] a first rotor and a second rotor, 3. The flexible drive shaft according to item 1 or 2, wherein the protruding direction of the second rotor is different from the protruding direction of the first rotor in the circumferential direction of the main shaft.

[0087] [Item 5] 5. The flexible drive shaft according to any one of items 1 to 4, wherein the rotor has a spherical shape.

[0088] [Item 6] 6. The flexible drive shaft according to any one of items 1 to 5, wherein the rotor protrudes from the main shaft by a height of 0.10 mm or more.

[0089] [Item 7] 7. The flexible drive shaft according to any one of items 1 to 6, having an apparent outer diameter that is 5.0 times or less the outer diameter of the main shaft.

[0090] [Item 8] 8. A flexible drive shaft according to any one of items 1 to 7, wherein the main shaft has a plurality of gaps, each gap being inclined with respect to the axial direction of the main shaft.

[0091] [Item 9] Item 9. The flexible drive shaft according to item 8, wherein the main shaft has a coil.

[0092] [Item 10] Item 10. The flexible drive shaft according to item 9, wherein the main shaft includes a first coil and a second coil located outside the first coil and having a winding direction different from the winding direction of the first coil.

[0093] [Item 11] 11. The flexible drive shaft according to any one of items 1 to 10, wherein the material of the main shaft is stainless steel.

[0094] [Item 12] a sheath, a flexible drive shaft passing through the sheath, and a drive fixed to the flexible drive shaft; The flexible drive shaft is Hollow main shaft and Multiple rotors attached to this main shaft It has A medical device wherein each rotor protrudes from an outer circumferential surface of the main shaft. [Industrial Applicability]

[0095] The flexible drive shaft described above is suitable for a variety of devices that require the transmission of drive force. [Explanation of symbols]

[0096] 2. Flexible drive shaft 4. Main shaft 6. Retainer 8. Rotor 10. First coil 12 Second coil 14...first strand 16. First gap 18...Second wire 20...Second gap 22...Lower cylinder 24···Pedestal 26...Upper tube 28 Notch 30... Press 32 Flexible drive shaft 34 Main shaft 36 Retainer 38 Rotor 40 First coil 42 Second coil 44 Third coil 46...first strand 48 First Gap 50...Second strand 52...Second gap 54...Third wire 56...Third Gap 58 Flexible drive shaft 60 Main shaft 62 Retainer 64···Rotor 66 Flexible drive shaft 68 Main shaft 70 Retainer 72 Rotor 74...lower tube 76···Pedestal 78...Upper tube 80...hole 82 Flexible drive shaft 84 Main shaft 86 Retainer 88 Rotor 90...Body 92 Side plate 93...hole 94...hole 96 Chamber 98 Flexible drive shaft 100···Main shaft 102 Retainer 104 Rotor 106 First coil 108 Second coil 110...First strand 112...Second wire 114···Rail 116···Base 118...lower tube 120···Base 122...upper cylinder 124...Notch 126···Press 128 Flexible drive shaft 130 Main shaft 132 Retainer 134 Rotor 136 First coil 138 Second coil 140...First strand 142...Second wire 144...Groove 146...Lower tube 148···Pedestal 150...Upper tube 152 feet 154...Press 156 Flexible drive shaft 158···Main shaft 160···Retainer 162 Rotor 164 Sub-rotor 166···Body 168···End cover 170...hole 172...hole 174 Chamber 176 Main Chamber 178 Sub-chamber

Claims

1. Hollow main shaft and Multiple rotors attached to this main shaft It is equipped with A flexible drive shaft, wherein each rotor protrudes from the outer circumferential surface of the main shaft.

2. Further comprising a plurality of retainers; Each retainer is spaced apart from the other retainers, 2. The flexible drive shaft according to claim 1, wherein the rotor is attached to the main shaft via the retainer.

3. The retainer has a chamber extending along the axial direction of the main wire, The chamber accommodates a first rotor, a second rotor, and a sub-rotor; the second rotor is spaced apart from the first rotor, the sub rotor is located between the first rotor and the second rotor in the axial direction of the main wire, 3. The flexible drive shaft according to claim 2, wherein the sub-rotor abuts the first rotor and abuts the second rotor.

4. a first rotor and a second rotor, 3. The flexible drive shaft according to claim 1, wherein a protruding direction of the second rotor is different from a protruding direction of the first rotor in the circumferential direction of the main shaft.

5. 3. The flexible drive shaft of claim 1, wherein the rotor has a spherical shape.

6. 3. The flexible drive shaft according to claim 1, wherein the rotor protrudes from the main shaft by a height of 0.10 mm or more.

7. 3. The flexible drive shaft according to claim 1, having an apparent outer diameter that is 5.0 times or less the outer diameter of the main shaft.

8. 3. The flexible drive shaft according to claim 1, wherein the main shaft has a plurality of gaps, each gap being inclined relative to the axial direction of the main shaft.

9. The flexible drive shaft of claim 7 wherein the main shaft comprises a coil.

10. 9. The flexible drive shaft of claim 8, wherein the main shaft includes a first coil and a second coil located outside the first coil and having a winding direction different from that of the first coil.

11. 3. The flexible drive shaft according to claim 1, wherein the main shaft is made of stainless steel.

12. a sheath, a flexible drive shaft passing through the sheath, and a drive fixed to the flexible drive shaft; The flexible drive shaft is Hollow main shaft and Multiple rotors attached to this main shaft It has A medical device wherein each rotor protrudes from an outer circumferential surface of the main shaft.

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