JP2023077953A - Multi-layer coil structure - Google Patents

Abstract

To provide a multi-layer coil structure that suppresses twist rigidity low without sacrificing a torque force.SOLUTION: A torque coil (a multi-layer coil structure) 10 includes an inner coil 11 formed by spirally winding a metal element wire 111 and an outer coil 12 which is arranged, adhered to an outer periphery of the inner coil 11, and is formed by spirally winding a metal element wire 121. In the torque coil 10, it is preferable that a winding direction of the inner coil 11 and a winding direction of the outer coil 12 are the same and that a winding angle α in a vertical cross sectional direction of the inner coil 11 is larger than a winding angle β in a vertical cross sectional direction of the outer coil 12.SELECTED DRAWING: Figure 2

Description

The present invention relates to multilayer coil structures.

2. Description of the Related Art Conventionally, multilayer coil structures called torque coils and drive shafts, which are disposed inside medical catheters and the like and used to transmit the rotational motion of a handheld operating portion to the distal end portion, are known. For example, U.S. Pat. No. 6,200,400 discloses a hollow coil with an inner coil 40 and an outer coil 42 formed from wound nitinol disposed within a catheter sheath 18 of an acoustic imaging (ultrasound imaging) catheter 10. A drive shaft 16 is disclosed.

Such a multilayer coil structure is rotationally driven by a drive source such as a motor connected to the hand side. The winding direction (twisting direction) of the inner coil is opposite to the winding direction of the outer coil. With such a configuration, when twisting is applied in the circumferential direction and in the direction in which the diameter of the inner coil expands, the diameter of the inner coil expands and the diameter of the outer coil shrinks, increasing the adhesion between the layers. Therefore, the torsional rigidity of the multilayer coil structure is enhanced, and a high torque force is realized.

Japanese Patent Publication No. 09-504214

On the other hand, when such a multi-layer coil structure is used as a drive shaft of a lesion cutting device for scraping a lesion such as a thrombus in a blood vessel with a distal tip, if the torsional rigidity is too high, the distal tip may damage the inside of the blood vessel. There is a possibility that In order to keep the torsional rigidity low, it is conceivable to reduce the number of strands of wire that constitute the inner coil and the outer coil. , there is a problem that it becomes impossible to secure the torque force necessary for cutting the lesion.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-layer coil structure in which torsional rigidity is kept low without sacrificing torque force.

In order to achieve the above object, the present invention provides an inner coil formed by spirally winding a metal wire, and an inner coil disposed in close contact with the outer circumference of the inner coil, and a metal wire wound spirally. and an outer coil, wherein the winding direction of the inner coil is the same as the winding direction of the outer coil (Invention 1).

According to this invention (Invention 1), since the winding direction of the inner coil and the winding direction of the outer coil are the same, the multilayer coil structure is arranged in the circumferential direction and in the direction in which the diameter of the inner coil is reduced. Since both the diameter of the inner coil and the diameter of the outer coil shrink when twisted, the adhesion force between the layers does not suddenly increase, and the torsional stiffness of the multi-layer coil structure is kept low without sacrificing the torque force. be able to.

In the above invention (Invention 1), it is preferable that the winding angle of the inner coil in the vertical cross-sectional direction is larger than the winding angle of the outer coil in the vertical cross-sectional direction (Invention 2).

According to this invention (invention 2), the winding angle of the inner coil is larger than the winding angle of the outer coil, so that the multilayer coil structure is twisted in the circumferential direction and in the direction in which the diameter of the inner coil is reduced. In this case, the amount of change in the diameter of the outer coil becomes larger than the amount of change in the diameter of the inner coil, and the outer coil shrinks more than the inner coil. As a result, the adhesion between the layers of the inner coil and the outer coil is increased, and sufficient torque force and stretch resistance can be obtained. Since the layers are not pressed against each other, the degree of increase in adhesion between the layers is gradual, and a multilayer coil structure with low torsional rigidity can be realized without sacrificing the torque force.

In the above inventions (inventions 1 and 2), the radial length in the cross section of the metal wire forming the inner coil is 70% of the radial length in the cross section of the metal wire forming the outer coil. The above is preferable (Invention 3).

According to the present invention, it is possible to provide a multilayer coil structure in which torsional rigidity is kept low without sacrificing torque force.

FIG. 4 is an explanatory diagram showing the structure of a torque coil according to one embodiment of the present invention; It is explanatory drawing which shows the structure of the shaft main body which concerns on the same embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing the overall structure of a torque coil 10 according to this embodiment, and FIG. 2 is an explanatory diagram showing the structure of a shaft body 1 in the torque coil 10. As shown in FIG. It should be noted that the present invention is not limited only to the embodiments described below, and the embodiments are merely exemplifications described to explain the technical features of the present invention. Moreover, the shapes and dimensions shown in each drawing are shown only for the purpose of facilitating the understanding of the contents of the present invention, and do not reflect the actual shapes and dimensions correctly.

In this specification, the term "distal end side" means a direction along the axial direction of the shaft body 1 that constitutes the torque coil 10, which is the direction in which the torque coil 10 advances toward the treatment site. “Base end side” means a direction along the axial direction of the shaft body 1 constituting the torque coil 10 and opposite to the tip end side. In addition, the term “distal end” refers to the distal end of any member or site, and the term “basal end” refers to the proximal end of any member or site. Furthermore, the term "distal end" refers to a region of any member or site that includes the distal end and extends from the distal end toward the proximal side to the middle of the member, etc., and the term "proximal end" refers to any part. In a member or region, it refers to a portion that includes the proximal end and extends from the proximal end toward the distal side to the middle of the member or the like. 1 and 2, the left side of the drawing is the "distal side" where the catheter is inserted into the body, and the right side of the drawing is the "proximal side" where it is connected to a driving source such as a motor. ”.

The torque coil 10, as shown in FIG. Prepare. Further, a drive source (not shown) such as a motor for rotationally driving the torque coil 10 is provided via the connector 3 on the base end side of the connector 3 . As shown in FIG. 2, the shaft body 1 in the present embodiment includes an inner coil 11 formed by spirally winding a metal wire 111, and a metal wire 111 disposed in close contact with the outer periphery of the inner coil 11. An outer coil 12 formed by spirally winding 121 has a hollow two-layer coil structure. The shaft body 1 may have at least two layers of the inner coil 11 and the outer coil 12, and may have a multilayer coil structure of three or more layers.

The torque coil 10 is used as a lesion cutting device for scraping a lesion such as a thrombus in a blood vessel. A distal tip 2 is attached to the tip of the shaft body 1 of the torque coil 10 to scrape the lesion by rotating at high speed. It is The tip 2 is a metal member having fine irregularities formed on its outer surface, and is attached to the tip of the shaft body 1 by a known fixing technique such as epoxy resin or adhesive. The shape and material of the tip are not particularly limited as long as they can be rotated at high speed to scrape off the lesion. good. The fine unevenness can be formed by adhering inorganic fine particles such as metal fine particles or diamond to the outer surface of the tip 2 . Depending on the application of the torque coil 10, instead of the tip 2, a coil member made of a material different from that of the shaft body 1 may be joined, or a connecting member such as a medical clip for connecting to an operation object may be joined. Alternatively, the tip of the shaft body 1 may be brazed with a brazing material and cut into a desired shape. The torque coil of the present invention is particularly effective in shafts used in lesion cutting devices that rotate at high speeds of 10,000 rpm or higher, more preferably 50,000 rpm or higher, and even more preferably 100,000 rpm or higher.

A connector 3 for connecting to a driving source such as a motor for rotationally driving the torque coil 10 is attached to the proximal end of the shaft body 1 of the torque coil 10 by a known fixing technique such as epoxy resin or adhesive. ing.

In this embodiment, the outer diameter of the inner coil 11 is set in the range of 0.22 to 0.74 mm, and the inner diameter is set in the range of 0.15 to 0.52 mm. Although the material of the metal wire 111 forming the inner coil 11 is not particularly limited, for example, austenitic stainless steel such as SUS304 and SUS316 is used.

The inner coil 11 is formed by spirally winding a plurality of metal wires 111, and is formed so that there is no gap between adjacent metal wires 111 in the axial direction of the inner coil 11. . In this embodiment, the inner coil 11 is formed by spirally winding 2 or more and 18 or less metal wires. In the case of a round wire, it means the diameter of the metal wire 111) is set in the range of 0.03 to 0.11 mm.

In this embodiment, the outer diameter of the outer coil 12 is set in the range of 0.3 to 1.0 mm, and the inner diameter is set in the range of 0.22 to 0.74 mm. Since the outer coil 12 is arranged in close contact with the outer circumference of the inner coil 11 , the inner diameter of the outer coil 12 is set to be substantially equal to or slightly larger than the outer diameter of the inner coil 11 . Although the material of the metal wire 121 forming the outer coil 12 is not particularly limited, for example, austenitic stainless steel such as SUS304 and SUS316 is used. Metal wire 111 forming inner coil 11 and metal wire 121 forming outer coil 12 are preferably made of the same material.

The outer coil 12 is formed by spirally winding a plurality of metal wires 121, and is formed so that there is no gap between adjacent metal wires 121 in the axial direction of the outer coil 12. . In this embodiment, the outer coil 12 is formed by spirally winding 2 or more and 18 or less metal wires. In the case of a round wire, it means the diameter of the metal wire 121) is set in the range of 0.04 to 0.13 mm.

In the present embodiment, both the metal wire 111 forming the inner coil 11 and the metal wire 121 forming the outer coil 12 are round wires having a substantially circular cross section, but they are not particularly limited to this. Instead, it may be a round wire with an elliptical cross section, or a flat wire with a substantially rectangular cross section.

In the shaft body 1, as shown in FIG. 2, the outer coil 12 is arranged on the outer circumference of the inner coil 11 so that the winding direction of the inner coil 11 and the winding direction of the outer coil 12 are the same. there is Thus, when the shaft body 1 is twisted in its circumferential direction and in the direction in which the diameter of the inner coil 11 is reduced, both the diameter of the inner coil 11 and the diameter of the outer coil 12 are reduced.

Here, in the torque coil 10, when the shaft body 1 is twisted in the circumferential direction and in the direction in which the diameter of the inner coil 11 shrinks, the amount of change in the diameter of the outer coil 12 is larger than the amount of change in the diameter of the inner coil 11. configured to grow. Specifically, as shown in FIG. 2, the winding angle α of the inner coil 11 in the longitudinal cross-sectional direction and the winding angle β of the outer coil 12 in the longitudinal cross-sectional direction are different from each other. The winding angle α in the longitudinal cross-sectional direction is set to be larger than the winding angle β in the longitudinal cross-sectional direction of the outer coil 12 . Thus, the winding angle α of the inner coil 11 is larger than the winding angle β of the outer coil 12 (that is, the twist angle of the inner coil 11 is higher than the twist angle of the outer coil 12). Thus, when the shaft body 1 is twisted in its circumferential direction and in the direction in which the diameter of the inner coil 11 is reduced, the amount of change in the diameter of the outer coil 12 becomes larger than the amount of change in the diameter of the inner coil 11. .

The relationship between the winding angle α of the inner coil 11 in the longitudinal cross-sectional direction and the winding angle β of the outer coil 12 in the longitudinal cross-sectional direction is determined by the metal wires 111 and 121 forming the inner coil 11 and the outer coil 12, respectively. It is determined by a combination of wire diameter and thread number settings. For example, if the diameter of the wire forming the coil is fixed, the more the number of coil threads, the smaller the winding angle in the longitudinal cross-sectional direction of the coil. The winding angle in the longitudinal cross-sectional direction increases. In addition, if the number of coil threads is fixed, the larger the diameter of the wire forming the coil, the smaller the winding angle in the longitudinal cross-sectional direction of the coil, and the smaller the diameter of the wire forming the coil. As the thickness increases, the winding angle in the vertical cross-sectional direction of the coil increases.

The winding angle α in the vertical cross-sectional direction of the inner coil 11 can be appropriately adjusted for the purpose of controlling the adhesion force with the outer coil 12. For example, it is preferably 10 degrees or more and 89 degrees or less. It is particularly preferable from the viewpoint of keeping the torsional rigidity low without sacrificing the torque force. In addition, the winding angle β of the outer coil 12 in the longitudinal cross-sectional direction is preferably 10 degrees or more and 89 degrees or less, and preferably 60 degrees or more and 80 degrees or less, for the purpose of controlling the adhesion force with the inner coil 11. is particularly preferable from the viewpoint of keeping torsional rigidity low without sacrificing torque force. At this time, the angle difference (α−β) between the winding angle α in the longitudinal cross-sectional direction of the inner coil 11 and the winding angle β in the longitudinal cross-sectional direction of the outer coil 12 is, for example, −79 degrees or more and +79 degrees or less. It's okay. In particular, from the viewpoint of keeping the torsional rigidity low without sacrificing the torque force, the winding angle α in the longitudinal cross-sectional direction of the inner coil 11 is the same as or the winding angle β in the longitudinal cross-sectional direction of the outer coil 12. It is preferably larger than β, and the angle difference (α−β) is more preferably 0 degree or less, and more preferably −1 degree or less. Further, from the viewpoint of keeping the torsional rigidity low without sacrificing the torque force, the angle difference (α-β) is preferably -20 degrees or more, more preferably -10 degrees or more, and particularly preferably -5 degrees or more.

In this embodiment, the diameter of the metal wire 111 forming the inner coil 11 is preferably 70% or more of the diameter of the metal wire 121 forming the outer coil 12 . When the diameter of the metal wire 111 forming the inner coil 11 is significantly smaller than the diameter of the metal wire 121 forming the outer coil 12, the metal wire 111 of the inner coil 11 and the metal wire 121 of the outer coil 12 are separated from each other. The difference in the rigidity of the shaft body 1 becomes large, and it becomes difficult to maintain the coil shape.

In a conventional torque coil in which the winding directions of the inner coil and the outer coil are opposite, when the twist is applied in the circumferential direction and in the direction in which the diameter of the inner coil expands, the diameter of the inner coil expands and the diameter of the outer coil expands. Since the contraction increases the adhesion between the layers, the torsional rigidity is enhanced and a high torque force is realized. On the other hand, in the torque coil 10 described above, the winding direction of the inner coil 11 and the winding direction of the outer coil 12 are the same, and the shaft body 1 is rotated in the circumferential direction and the direction in which the diameter of the inner coil 11 is reduced. Since the diameter of the inner coil 11 and the diameter of the outer coil 12 both shrink when twisted, the adhesion between the layers does not suddenly increase, and the torsional rigidity of the torque coil 11 is reduced without sacrificing the torque force. It can be suppressed.

In particular, if the winding angle α of the inner coil 11 is larger than the winding angle β of the outer coil 12, when the shaft body 1 is twisted in its circumferential direction and in the direction in which the diameter of the inner coil 11 shrinks, The amount of change in the diameter of the coil 12 becomes larger than the amount of change in the diameter of the inner coil 11, and the outer coil 12 contracts more than the inner coil 11. Therefore, when the shaft body 1 is twisted, the inner coil 11 and The adhesion between the layers of the outer coil 12 is increased, and sufficient torque and elongation resistance can be obtained. On the other hand, when the shaft body 1 is twisted, the outer coil 12 and the inner coil 11 do not press against each other unlike the conventional torque coil, so the degree of increase in the adhesion between the layers is moderate. As a result, the torsional rigidity of the torque coil 11 can be kept low without sacrificing the torque force.

Furthermore, the torque coil 10 described above can control the torsional rigidity of the torque coil 10 by adjusting the angle difference between the winding angle α of the inner coil 11 and the winding angle β of the outer coil 12 . For example, the larger the angle difference between the winding angle α of the inner coil 11 and the winding angle β of the outer coil 12, the more the outer coil 12 shrinks than the inner coil 11. The adhesion between the layers of the inner coil 11 and the outer coil 12 is increased when the coil is folded, and the torsional rigidity can be increased. The flexibility of the torque coil 10 is also controlled by adjusting the number (number of threads) of the metal wires 111 forming the inner coil 11 and the number (number of threads) of the metal wires 121 forming the outer coil 12. You can also

Although the torque coil (multilayer coil structure) according to the present invention has been described above with reference to the drawings, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the shape, length, diameter, etc. of the inner coil 11 and the outer coil 12 constituting the torque coil 1 may be appropriately designed according to the purpose of use, the position of use, and the like. Further, a lead wire or the like may be inserted inside the shaft body 1, or a member other than the inner coil 11 and the outer coil 12, such as a reinforcing member or an X-ray opaque marker, may be provided in the shaft body 1. may have been

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

In order to verify that the torque coil according to the present invention can keep the torsional rigidity low without sacrificing the torque force, the inner coil is a multi-strand coil formed by spirally winding a plurality of metal wires. and an outer coil, which is a multi-strand coil formed by spirally winding a plurality of metal wires, arranged in close contact with the outer circumference of the inner coil, and a plurality of test torque coils are manufactured, and the motor and A torque sensor was used to measure the maximum torque force and torsional rigidity.

All test torque coils were made of SUS304, and a plurality of test torque coils were produced by changing the wire diameter and the number of strands of the inner and outer coils. Table 1 shows the structures of the inner coil and the outer coil of the manufactured test torque coil.

In Examples 1 and 2 in Table 1, the inner coil and the outer coil are wound in the same direction, and in Comparative Example 1, the inner coil and the outer coil are wound in opposite directions. In addition, the pitch in Table 1 means the length of one cycle of the wound wire.

Subsequently, the test torque coils of each example and comparative example thus prepared were attached to a guide wire transfer characteristic measuring instrument PT-1950GHS (manufactured by Protech Co., Ltd.) equipped with a motor and a torque sensor, and rotated in the forward direction by the motor. The torsion rigidity and the maximum torque force of the test torque coils of each example and comparative example were measured. The measurement was performed three times for each example and comparative example, and the average value was calculated as the measurement result. Table 2 shows the measurement results.

Furthermore, a three-point bending test was performed on the manufactured test torque coils of each example and comparative example to measure the bending rigidity of each test torque coil of each example and comparative example. The 3-point bending test was performed using a testing device (model: AUTOGRAPH AGS-X 10N) manufactured by Shimadzu Corporation, setting the distance between fulcrums at 5 mm and the test speed at 5 mm/min. The measurement was performed three times for each example and comparative example, and the average value was calculated as the measurement result. Table 3 shows the measurement results.

According to the measurement results shown in Table 2, in Examples 1 and 2, the torsional rigidity can be kept low without sacrificing the torque force. Compared with Comparative Example 1, it can be seen that the torque force can be significantly improved.

Further, according to the measurement results shown in Table 3, it can be seen that the flexural rigidity of Examples 1 and 2 is higher than that of Comparative Example 1.

10 torque coil (multilayer coil structure)
REFERENCE SIGNS LIST 1 shaft body 11 inner coil 12 outer coil 2 distal tip 3 connector

Claims (3)

an inner coil formed by spirally winding a metal wire;
an outer coil arranged in close contact with the outer periphery of the inner coil and formed by spirally winding a metal wire,
A multilayer coil structure, wherein the winding direction of the inner coil and the winding direction of the outer coil are the same. 2. The multilayer coil structure according to claim 1, wherein the winding angle of the inner coil in the longitudinal cross-sectional direction is larger than the winding angle of the outer coil in the longitudinal cross-sectional direction. 3. The metal wire forming the inner coil according to claim 1, wherein the radial length in the cross section of the metal wire forming the inner coil is 70% or more of the radial length in the cross section of the metal wire forming the outer coil. multilayer coil structure.

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