CN110074819B

CN110074819B - Transmission shaft of intravascular ultrasonic catheter transducer

Info

Publication number: CN110074819B
Application number: CN201910459596.4A
Authority: CN
Inventors: 陈丽丽; 胡文城; 李连波
Original assignee: Shenzhen Insight Med Co ltd; Insight Lifetech Co Ltd
Current assignee: Shenzhen Insight Med Co ltd; Insight Lifetech Co Ltd
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2022-03-25
Anticipated expiration: 2039-05-29
Also published as: CN110074819A; CN114533124A

Abstract

The present disclosure relates to a transmission shaft of an intravascular ultrasound catheter transducer, which is characterized by comprising: an inner layer structure, which is formed as a first spring structure braided by braided wires, and the pitch of the first spring structure is from The distal end to the proximal end gradually increases; and the outer layer structure covers the inner layer structure, the outer layer structure is formed as a second spring structure, and the pitch of the second spring structure gradually increases from the distal end to the proximal end, the first The pitch of the two-spring structure is more sparse than the pitch of the first-spring structure. In this case, the mechanical properties of the inner structure and the outer structure of the drive shaft are complementary, so that the flexibility of the drive shaft can be improved while the stress response capability and torque transmission capability of the drive shaft can be enhanced, which helps to avoid the occurrence of Uneven rotation artifact, while improving the twist control performance on the long-range control of the intravascular ultrasound catheter, improving the overall maneuverability, effectively reducing the operation time, and providing medical services more efficiently.

Description

Transmission shaft of intravascular ultrasonic catheter transducer

Technical Field

The present disclosure relates to a drive shaft for an intravascular ultrasound catheter transducer.

Background

The IVUS system, also known as an intravascular ultrasound imaging system, is mainly composed of an IVUS catheter, an IVUS retraction system, and an IVUS host system. In practice, an IVUS catheter containing a miniature ultrasound transducer and its drive shaft is typically advanced to the vascular lesion via a radial or femoral artery puncture. The tube core of the catheter acquires the sectional structure information of the lumen and the wall of the blood vessel through the miniature ultrasonic transducer at the front end of the tube core in the retracting process, then the imaging is carried out on a host system, the image processing is carried out, and finally the transverse section and the longitudinal section of the lumen and the wall of the blood vessel in a specific range are respectively displayed in the form of images.

During the detection imaging of a blood vessel by an ultrasonic transducer, it is generally required that the drive shaft of the ultrasonic transducer be kept rotating rapidly and, at the same time, be retracted at a uniform speed. In order to safely pass through blood vessels with variable path curves and intersections, the transmission shaft is often required to have better flexibility, and simultaneously have larger torque transmission capacity and more sensitive stress response capacity. However, the transmission shaft applied in the current market generally needs not to have larger torque transmission capability but too large rigidity, does not move smoothly in the blood vessel, easily causes blood vessel damage, needs not to have better flexibility but smaller torque transmission capability or has slower stress response, causes the rotating and withdrawing speeds of the ultrasonic transducer to deviate from the preset value, generates uneven rotation artifacts, and brings the risk of longer operation time consumption or poorer imaging quality to the clinical application of the intravascular ultrasonic imaging.

Disclosure of Invention

The present disclosure has been made in view of the above-mentioned state of the art, and an object thereof is to provide a drive shaft of an intravascular ultrasound catheter transducer which has excellent flexibility and excellent stress response capability and torque transmission capability.

To this end, the present disclosure provides a drive shaft (or simply "drive shaft" in this application) for an intravascular ultrasound catheter transducer that is composed of two layers of different structures. Wherein the drive shaft comprises a proximal portion and a distal portion having an ultrasonic catheter transducer, comprising: an inner layer structure formed as a first spring structure woven from a braided wire, the first spring structure having a pitch that gradually increases from the distal end to the proximal end; and an outer layer structure covering the inner layer structure, the outer layer structure being formed as a second spring structure, and a pitch of the second spring structure gradually increasing from the distal end to the proximal end, the pitch of the second spring structure being sparser than the pitch of the first spring structure.

In the present disclosure, an intravascular ultrasound transducer drive shaft includes two layers of tubes separated into an inner layer structure and an outer layer structure, both of which include spring structures whose pitch can be gradually varied, and the pitch of the spring structures of the outer layer is more sparse than that of the inner layer. Under the condition, the mechanical properties of the inner layer structure and the outer layer structure of the transmission shaft are complementary, so that the flexibility of the transmission shaft is improved, the stress response capability and the moment transmission capability of the transmission shaft are enhanced, and the intravascular ultrasonic imaging quality is improved.

In addition, in the propeller shaft according to the present disclosure, an adhesive is optionally disposed between the inner layer structure and the outer layer structure. This improves the reliability of the connection between the inner layer structure and the outer layer structure.

In the propeller shaft according to the present disclosure, the young's modulus of the first spring structure may be larger than the young's modulus of the second spring structure. Under the condition, the torque transfer capacity and the stress response capacity of the first spring structure are better, the flexibility of the second spring structure is better, and the mechanical properties of the inner layer structure and the outer layer structure of the transmission shaft are complementary, so that the flexibility of the transmission shaft can be improved, and the stress response capacity and the torque transfer capacity of the transmission shaft are enhanced.

In addition, in the propeller shaft according to the present disclosure, optionally, a wall thickness of the inner layer structure is larger than a wall thickness of the outer layer structure. This can further improve the stress response capability and the torque transmission capability of the propeller shaft.

In addition, in the propeller shaft according to the present disclosure, the braided wire may be made of a metal wire or a polymer wire. In this case, the strength of the inner layer structure is improved, so that the stress response capability and the moment transmission capability of the propeller shaft can be further improved.

In addition, in the propeller shaft according to the present disclosure, optionally, the metal wire is made of at least one selected from a steel alloy, a nickel-titanium alloy, a copper alloy, a cobalt-chromium alloy, pure platinum, pure gold, or pure tungsten. This can further improve the stress response capability and the torque transmission capability of the propeller shaft.

In the propeller shaft according to the present disclosure, the polymer filaments may be made of at least one selected from nylon, silicone rubber, polyurethane, polyether ether ketone (PEEK), and Liquid crystal polymer (Liquid crystal polymer). This can further improve the stress response capability and the torque transmission capability of the propeller shaft.

In addition, in the propeller shaft according to the present disclosure, optionally, the first spring structure is formed by weaving at least one strand of the braided wire. Thereby, the flexibility, stress response capability and torque transmission capability of the propeller shaft can be further improved.

In addition, in the propeller shaft according to the present disclosure, a protective layer covering the outer layer structure may be optionally further included. This can reduce damage to the blood vessel by the propeller shaft.

In addition, in the propeller shaft according to the present disclosure, optionally, the braided wire is a flat wire. Therefore, the stress response capability and the moment transmission capability of the transmission shaft can be improved, and the reduction of the outer diameter of the transmission shaft is facilitated.

Drawings

Fig. 1 is a schematic view showing an application of a propeller shaft according to an embodiment of the present disclosure.

Fig. 2 is a schematic structural view showing a propeller shaft according to the present embodiment.

Fig. 3 is a partially enlarged view showing a drive shaft according to the present embodiment near a distal end.

Fig. 4 is a schematic diagram showing an inner layer structure according to the present embodiment.

Fig. 5 is a schematic diagram showing the outer layer structure according to the present embodiment.

Fig. 6 is a partial cross-sectional view showing a propeller shaft including a protective layer according to the present embodiment.

Description of the symbols:

1 … drive shaft, 11 … proximal end, 12 … distal end, 13 … inner layer structure, 131 … first spring structure, 1311 … braided wire, 14 … outer layer structure, 141 … second spring structure, 15 … protective layer, 2 … retraction device, 3 … ultrasonic probe, 31 … ultrasonic transducer.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals, and redundant description thereof is omitted. The drawings are schematic and the ratio of the dimensions of the components and the shapes of the components may be different from the actual ones.

In the following description, the description is made in the manner of using subtitles for convenience of description, but these subtitles merely play a role of cue and are not intended to limit the contents described under the subtitles to the subject matter of the subtitles.

In the present embodiment, both end portions of the drive shaft 1 may be referred to as a proximal end 11 and a distal end 12, respectively. In this embodiment, the proximal end 11 may be connected to a withdrawal device 2 arranged outside the body. In this embodiment, the distal end 12 may be connected to an ultrasound probe 3 including an ultrasound transducer 31. In this case, the distal end 12 and the ultrasonic probe 3 are placed in the blood vessel, the drive shaft 1 carries the ultrasonic probe 3 to be uniformly retracted and rotated by the retracting device 2, and the ultrasonic transducer 31 detects the structure in the blood vessel, so that ultrasonic imaging of the inside of the blood vessel can be obtained.

In some examples, the drive shaft 1 and the ultrasound probe 3 may be disposed inside a sheath (not shown). In this case, the sheath covers the drive shaft 1 and the ultrasonic probe 3 in the blood vessel, and the drive shaft 1 and the ultrasonic probe 3 are retracted and rotated in the sheath, so that the retraction and rotation of the drive shaft 1 can be made smoother, and it is helpful to protect the blood vessel from being damaged by the drive shaft 1 or the ultrasonic probe 3.

In some examples, the sheath may be made of at least one of a rubber-plastic material and a resin. Specifically, in some examples, the sheath may be made of at least one material selected from ethylene-vinyl acetate copolymer (EVA), polyetheretherketone, polyethylene, linear low density polyethylene. This can further improve the smoothness of the retraction and rotational movement of the propeller shaft 1, and contribute to protecting the blood vessel from being damaged by the propeller shaft 1 or the ultrasonic probe 3.

Fig. 2 is a schematic structural view showing a propeller shaft according to the present embodiment. Fig. 3 is a partially enlarged view showing a drive shaft according to the present embodiment near a distal end.

In the present embodiment, the transmission shaft 1 may include an inner layer structure 13 and an outer layer structure 14, the inner layer structure 13 may be formed as a first spring structure 131 woven by a weaving wire 1311, a pitch of the first spring structure 131 may gradually increase from the distal end 12 to the proximal end 11, the outer layer structure 14 may cover the inner layer structure 13, the outer layer structure 14 may be formed as a second spring structure 141, a pitch of the second spring structure 141 may gradually increase from the distal end 12 to the proximal end 11, and a pitch of the second spring structure 141 may be sparser than a pitch of the first spring structure 131.

In this case, the mechanical properties of the inner layer structure 13 and the outer layer structure 14 of the transmission shaft 1 are complementary, so that the flexibility of the transmission shaft 1 can be improved, the stress response capability and the moment transmission capability of the transmission shaft 1 can be enhanced, and the intravascular ultrasonic imaging quality can be improved. In addition, the mechanical properties of the inner layer structure 13 and the outer layer structure 14 of the transmission shaft 1 are complementary, so that kinks or other harmful deformations generated when the transmission shaft 1 moves in blood vessels can be reduced, the operation time can be shortened, and the quality of intravascular ultrasonic imaging can be improved.

In the present embodiment, an adhesive may be disposed between the inner layer structure 13 and the outer layer structure 14. Thereby, the reliability of the connection of the inner layer structure 13 and the outer layer structure 14 can be improved.

In some examples, the adhesive may be provided only at both ends of the propeller shaft 1 between the inner layer structure 13 and the outer layer structure 14. This improves the reliability of the connection between the inner layer structure 13 and the outer layer structure 14, reduces the influence of the adhesive on the performance of the inner layer structure 13 or the outer layer structure 14, and reduces the weight of the propeller shaft 1.

In some examples, the adhesive between the inner layer structure 13 and the outer layer structure 14 may be selected from at least one of epoxy and UV light-curing glue. This can further improve the reliability of the connection between the inner layer structure 13 and the outer layer structure 14.

In other examples, the inner layer structure 13 and the outer layer structure 14 may be joined together by brazing. Thereby, the reliability of the connection of the inner layer structure 13 and the outer layer structure 14 can be improved.

In other examples, the inner layer structure 13 and the outer layer structure 14 may be connected together by mechanical clamping.

In other examples, no adhesive may be required between the inner layer structure 13 and the outer layer structure 14, and the inner layer structure 13 and the outer layer structure 14 may be connected by snapping or rubbing against each other.

In the present embodiment, the young's modulus of the first spring structure 131 may be greater than the young's modulus of the second spring structure 141. In this case, the torque transmission capability and the stress response capability of the first spring structure 131 are better, the flexibility of the second spring structure 141 is better, and the mechanical properties of the inner layer structure 13 and the outer layer structure 14 of the propeller shaft 1 are complementary, so that the flexibility of the propeller shaft 1 can be improved, and the stress response capability and the torque transmission capability of the propeller shaft 1 can be enhanced.

In this embodiment, the wall thickness of the inner layer structure 13 may be greater than the wall thickness of the outer layer structure 14. This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

In the present embodiment, the pitch of the second spring structures 141 may be more sparse than the pitch of the first spring structures 131. In this case, the young's modulus of the second spring structure 141 is larger than that of the first spring structure 131, so that the stress response capability and the moment transmission capability of the propeller shaft 1 can be further improved.

In some examples, the helical directions of the first and

second spring structures

131 and 141 may be opposite. So that the stress response capability and the moment transmission capability of the propeller shaft 1 can be further improved.

In other examples, the helical directions of the first and

second spring structures

131 and 141 may be the same.

(inner layer Structure)

In the present embodiment, the inner layer structure 13 may be formed as the first spring structure 131 woven by the braided wire 1311.

In this embodiment, the pitch of the first spring structure 131 may gradually decrease from the proximal end 11 to the distal end 12. In some examples, as shown in fig. 4, the pitch of the first spring structure 131 from the proximal end 11 to the distal end 12 may include P1a, P1b, and P1c in that order, with P1a being greater than P1b and P1b being greater than P1 c. In this case, on the one hand, the first spring structure 131 has a larger young's modulus at a portion near the proximal end 11, so that the stress response capability and the moment transmission capability of the transmission shaft 1 can be improved, i.e., the transmission shaft 1 can sensitively and accurately transmit the retracting and rotating motion of the retracting device 2 to the ultrasonic probe 3; on the other hand, the first spring structure 131 has a smaller young's modulus at a portion near the distal end 12, so that the flexibility of the propeller shaft 1 can be improved, that is, the propeller shaft 1 can be smartly and smoothly moved in a blood vessel having a complicated and varied path.

In some examples, the change in pitch of the first spring structures 131 may be continuously gradual. This can further improve the flexibility, stress response capability, and torque transmission capability of the propeller shaft 1, and can reduce stress concentration in the propeller shaft 1.

In other examples, the pitch of the first spring structure 131 may vary stepwise. Thereby, the flexibility, the stress response capability and the moment transmission capability of the propeller shaft 1 can be further improved, and the pitch of the first spring structure 131 can be conveniently set and manufactured.

In this embodiment, the first spring structure 131 may be woven from at least one strand of braid wire 1311. Thereby, the flexibility, the stress response capability, and the torque transmission capability of the propeller shaft 1 can be further improved.

In some examples, the first spring structure 131 may be braided from 6 to 9 strands of braided wire 1311. Thereby, the flexibility, the stress response capability, and the torque transmission capability of the propeller shaft 1 can be further improved.

In other examples, the first spring structure 131 may be braided from 16 to 32 strands of braided wire 1311. Thereby, the flexibility, the stress response capability, and the torque transmission capability of the propeller shaft 1 can be further improved.

In some examples, the number of strands of braided wire 1311 comprising first spring structure 131 may vary from proximal end 11 to distal end 12. Thereby, the flexibility, the stress response capability, and the torque transmission capability of the propeller shaft 1 can be further improved.

In some examples, the number of strands of braided wire 1311 comprising first spring structure 131 may decrease from proximal end 11 to distal end 12. Thereby, the flexibility, the stress response capability, and the torque transmission capability of the propeller shaft 1 can be further improved.

In some examples, the braided wire 1311 may be a flat wire. This improves the stress response capability and the torque transmission capability of the propeller shaft 1, and contributes to reducing the outer diameter of the propeller shaft 1.

In other examples, the cross-section of the braided wire 1311 perpendicular to the direction of extension may be substantially circular. However, the present embodiment is not limited to this, and the cross-sectional shape of the braided wire 1311 may be substantially square, oval, other regular shapes, or irregular shapes.

In the present embodiment, the braided wire 1311 may be made of a metal wire or a polymer wire. In this case, the strength of the inner layer structure 13 is improved, so that the stress response capability and the moment transmission capability of the propeller shaft 1 can be further improved.

In some examples, the wires comprising braided wire 1311 may be made from at least one selected from steel alloys, nickel titanium alloys, copper alloys, cobalt chromium alloys, pure platinum, pure gold yellow, or pure tungsten. This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

In some examples, the Polymer filaments constituting the braided wire 1311 may be made of at least one selected from nylon, silicone rubber, polyurethane, polyether ether ketone (PEEK), or Liquid Crystal Polymer (Liquid Crystal Polymer). This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

In some examples, the wires making up the braided wire 1311 may be made of a steel alloy, as is preferred.

(outer layer Structure)

In this embodiment, the pitch of the second spring structure 141 may gradually decrease from the proximal end 11 to the distal end 12. In some examples, as shown in fig. 5, the pitch of the second spring structure 141 from the proximal end 11 to the distal end 12 may include P2a, P2b, and P2c in order, with P2a being greater than P2b and P2b being greater than P2 c. In this case, on the one hand, the second spring structure 141 has a larger young's modulus at a portion near the proximal end 11, so that the stress response capability and the moment transmission capability of the transmission shaft 1 can be improved, i.e., the transmission shaft 1 can sensitively and accurately transmit the retracting and rotating motion of the retracting device 2 to the ultrasonic probe 3; on the other hand, the second spring structure 141 has a smaller young's modulus at a portion near the distal end 12, so that the flexibility of the propeller shaft 1 can be improved, that is, the propeller shaft 1 can be smartly and smoothly moved in a blood vessel having a complicated and varied path.

In some examples, the change in pitch of the second spring structure 141 may be continuously gradual. This can further improve the flexibility, stress response capability, and torque transmission capability of the propeller shaft 1, and can reduce stress concentration in the propeller shaft 1.

In other examples, the pitch of the second spring structure 141 may vary stepwise. Thereby, the flexibility, the stress response capability, and the torque transmission capability of the propeller shaft 1 can be further improved.

In some examples, the material comprising the second spring structure 141 may be selected from at least one of a steel alloy, a nickel-titanium alloy, a copper alloy, a cobalt-chromium alloy, pure platinum, pure gold, or pure tungsten. This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

In some examples, the material constituting the second spring structure 141 may be selected from at least one of nylon, silicone rubber, polyurethane, Polyetheretherketone (PEEK), or Liquid Crystal Polymer (Liquid Crystal Polymer). This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

In some examples, the second spring structure 141 may be preferably made of a steel alloy.

In some examples, a cross-section of the second spring structure 141 perpendicular to the extending direction may be substantially circular. This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

In other examples, the second spring structure 141 may be formed from a flat wire. This improves the stress response capability and the torque transmission capability of the propeller shaft 1, and contributes to reducing the outer diameter of the propeller shaft 1.

In other examples, the cross section of the second spring structure 141 perpendicular to the extending direction may also be substantially elliptical, square, other regular shapes or irregular shapes.

In some examples, the second spring structure 141 may be formed by a coil of spring wire.

In other examples, the second spring structure 141 may also be formed from a multi-strand spring wire spiral. This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

(protective layer)

In the present embodiment, the propeller shaft 1 may further include a protective layer 15 covering the outer layer structure 14. This can reduce damage to the blood vessel by the propeller shaft 1. In addition, the retraction and rotation of the drive shaft 1 can be smoother, and the blood vessel can be protected from being damaged or contaminated by the drive shaft 1.

In some examples, the material of the protective layer 15 may be biocompatible. This can reduce the harmful effect of the propeller shaft 1 on the blood vessel.

In some examples, the protective layer 15 may have a smooth outer wall. This can reduce friction between the propeller shaft 1 and the surrounding environment.

In some examples, the material of the protective layer 15 may be selected from at least one of polyimide, polystyrene, polyurethane, latex, and silicone. Thereby, the smoothness of the retraction and rotation movement of the propeller shaft 1 can be further improved, and it is helpful to protect the blood vessel from being damaged or contaminated by the propeller shaft 1.

In some examples, an adhesive may be disposed between the protective layer 15 and the outer layer structure 14. Thereby, the reliability of the connection of the protective layer 15 and the outer layer structure 14 can be improved.

In some examples, the adhesive may be provided only at both ends of the drive shaft 1 between the protective layer 15 and the outer layer structure 14. This improves the reliability of the connection between the protective layer 15 and the outer layer structure 14, reduces the influence of the adhesive on the performance of the protective layer 15 or the outer layer structure 14, and reduces the weight of the propeller shaft 1.

In some examples, the adhesive between the protective layer 15 and the outer layer structure 14 may be selected from UV curable glues. Thereby, the reliability of the connection of the protective layer 15 and the outer layer structure 14 can be improved.

In some examples, the protective layer 15 may be wrapped around the outer structure 14 by its own elasticity for attachment purposes. Thereby, the reliability of the connection of the protective layer 15 and the outer layer structure 14 can be improved.

In other examples, a tight connection between the protective layer 15 and the outer layer structure 14 may not be required, and relative sliding or movement may be permitted between the protective layer 15 and the outer layer structure 14.

In the present embodiment, the structures of the inner layer structure 13 and the outer layer structure 14 may be interchanged. That is, the inner layer structure 13 may be formed as the second spring structure 141, the pitch of the second spring structure 141 may gradually increase from the distal end 12 to the proximal end 11, the outer layer structure 14 may cover the inner layer structure 13, the outer layer structure 14 may be formed as the first spring structure 131 woven by the braided wire 1311, the pitch of the first spring structure 131 may gradually increase from the distal end 12 to the proximal end 11, and the pitch of the second spring structure 141 may be sparser than the pitch of the first spring structure 131. In this case, the mechanical properties of the inner layer structure 13 and the outer layer structure 14 of the transmission shaft 1 are complementary, so that the flexibility of the transmission shaft 1 can be improved, the stress response capability and the moment transmission capability of the transmission shaft 1 can be enhanced, and the intravascular ultrasonic imaging quality can be improved. In addition, the mechanical properties of the inner layer structure 13 and the outer layer structure 14 of the transmission shaft 1 are complementary, so that kinks or other harmful deformations generated when the transmission shaft 1 moves in blood vessels can be reduced, the operation time can be shortened, and the quality of intravascular ultrasonic imaging can be improved.

In this embodiment, the propeller shaft 1 may also include more spring structures. Thereby, the stress response capability and the torque transmission capability of the propeller shaft 1 can be further enhanced.

In some examples, the drive shaft 1 may include a third spring structure. In some examples, the third spring structure may be disposed outside of the outer layer structure 14. In other examples, a third spring structure is disposed between the outer layer structure 14 and the inner layer structure 13. In other examples, the third spring structure is disposed inside the inner structure 13. Thereby, the stress response capability and the torque transmission capability of the propeller shaft 1 can be further enhanced.

In some examples, the pitch of the third spring structure may gradually increase from the distal end 12 to the proximal end 11. Thereby, the flexibility, the stress response capability, and the torque transmission capability of the propeller shaft 1 can be further improved.

In some examples, the third spring structure may be braided from braid wire 1311.

In some examples, the third spring structure may be formed by a coil of spring wire.

In other examples, the third spring structure may also be formed by a multi-strand spring wire spiral. This can further improve the stress response capability and the torque transmission capability of the propeller shaft 1.

While the present disclosure has been described in detail above with reference to the drawings and the embodiments, it should be understood that the above description does not limit the present disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from the true spirit and scope of the disclosure, which fall within the scope of the disclosure.

Claims

1. a drive shaft of an intravascular ultrasound catheter transducer, the drive shaft comprises a proximal portion connecting a retraction device and a distal portion with an ultrasound catheter transducer, characterized in that:

include:

an inner layer structure formed as a first spring structure woven from a braided wire, the pitch of the first spring structure gradually increasing from the distal end portion to the proximal end portion; and

an outer layer structure covering the inner layer structure, the outer layer structure being formed as a second spring structure and the pitch of the second spring structure gradually increasing from the distal end portion to the proximal end portion , the pitch of the second spring structure is more sparse than the pitch of the first spring structure.

2. The transmission shaft as claimed in claim 1, wherein:

Between the inner layer structure and the outer layer structure, an adhesive is arranged.

3. The transmission shaft as claimed in claim 1, wherein:

The Young's modulus of the first spring structure is greater than the Young's modulus of the second spring structure.

4. The transmission shaft as claimed in claim 1, wherein:

The wall thickness of the inner layer structure is greater than the wall thickness of the outer layer structure.

5. The transmission shaft as claimed in claim 1, wherein:

The braided wire is made of metal wire or polymer wire.

6. The transmission shaft as claimed in claim 5, characterized in that:

The metal wire is made of at least one selected from steel alloys, nickel-titanium alloys, copper alloys, cobalt-chromium alloys, pure platinum, pure gold or pure tungsten.

7. The transmission shaft as claimed in claim 5, characterized in that:

The polymer silk is made of at least one selected from nylon, silicone rubber, polyurethane, polyetheretherketone (PEEK) or liquid crystal polymer.

8. The transmission shaft as claimed in claim 1, wherein:

The first spring structure is woven from at least one strand of the braided wire.

9. The transmission shaft as claimed in claim 1, wherein:

Also included is a protective layer covering the outer structure.

10. The transmission shaft of claim 1, wherein:

The braided wire is flat wire.