Flexible tube and bending structure

Abstract

To provide a flexible tube and a bending structure of a medical manipulator excellent in load resistance and bendability while achieving downsizing.SOLUTION: A flexible tube is formed of a plurality of wave washers 17 stacked in an axial direction and whose stacking state is held. The flexible tube includes a body part 15 that is bendable when being expanded or contracted in the axial direction. This can make linearity of a load characteristic of a bending angle and a load high, so that the flexible tube 3 excellent in load resistance and bendability can be obtained while achieving downsizing.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a flexible tube and a bending structure that can be applied to bending portions of medical manipulators such as surgical robots. [Background technology]

[0002] In recent medical treatments, medical manipulators such as robotic forceps for surgical robots and manual forceps have become widespread in order to reduce the burden on both patients and doctors during surgery.

[0003] Medical manipulators, such as robotic forceps and manual forceps, allow doctors to insert an arm together with an endoscopic camera through a small incision in the patient, allowing them to perform surgery with the feeling that they are actually moving the forceps while visually viewing the surgical field through a 3D monitor.

[0004] As such a medical manipulator, there is one, as disclosed in Patent Document 1, in which a bending portion of the arm is provided with a joint function, thereby ensuring a high degree of freedom and enabling more precise surgical operations.

[0005] This medical manipulator uses a coil spring at the bending point of the arm, and the coil spring is bent by pulling a drive wire that runs through the inside.

[0006] The arms of these medical manipulators are expected to be miniaturized to reduce the size of wounds and ease the mental and physical burden on patients, and accordingly, the bending parts used in the arms are also expected to be miniaturized.

[0007] However, in the technology of Patent Document 1, the bending portion is configured by a coil spring, and therefore there is a limit to how much the device can be made smaller due to the need to ensure load resistance and flexibility.

[0008] Such problems exist not only in medical manipulators such as robotic forceps and manual forceps as described above, but also in other medical manipulators such as endoscopic cameras. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-38075 Summary of the Invention [Problem to be solved by the invention]

[0010] The problem to be solved is that there is a limit to ensuring load resistance and flexibility while achieving miniaturization. [Means for solving the problem]

[0011] The present invention is most primarily characterized by a flexible tube through which a drive wire of a medical manipulator passes in an axial direction along an axis, the flexible tube being bent in response to operation of the drive wire, in order to achieve miniaturization while achieving excellent load-bearing capacity and flexibility, the flexible tube comprising a bendable main body having a plurality of wave washers stacked in the axial direction and maintained in a stacked state, each wave washer having a plurality of circumferential peaks that are convex on one side in the axial direction and concave on the other side in the axial direction, valleys between the peaks that are concave on one side in the axial direction and convex on the other side in the axial direction, inclined portions that are located between adjacent peaks and valleys in the circumferential direction and that are inclined in the axial direction so as to extend from the adjacent peaks to the valleys when viewed from the radial outside in normal conditions when not bent, and through portions that are provided only in the inclined portions and through which the drive wire passes in the axial direction. [Effects of the Invention]

[0012] In the present invention, the main body is constructed by stacking multiple wave washers, and each wave washer can bend by expanding and contracting in the axial direction, making it possible to obtain a flexible tube that is compact yet has excellent load-bearing capacity and flexibility. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a robotic forceps using a flexible tube (Example 1). [Figure 2] FIG. 2 is a front view of the robotic forceps of FIG. 1 (Example 1). [Figure 3] FIG. 2 is a cross-sectional view of the robotic forceps of FIG. 1 (Example 1). [Figure 4] FIG. 2 is a perspective view of the robotic forceps of FIG. 1 with a portion thereof omitted (Example 1). [Figure 5] FIG. 5 is a perspective view of the robotic forceps of FIG. 4 with a portion thereof further omitted (Example 1). [Figure 6] FIG. 6 is a side view of the robotic forceps of FIG. 5 (Example 1). [Figure 7] FIG. 5 is a perspective view showing a flexible tube of the robotic forceps of FIG. 4 (Example 1). [Figure 8] FIG. 5A is a side view showing the flexible tube of FIG. 4, and FIG. 5B is an enlarged view of part VIII of FIG. 5A (Example 1). [Figure 9] 1A and 1B are cross-sectional views of a flexible tube, in which (A) shows the tube in a normal state and (B) shows the tube in a bent state (Example 1). [Figure 10] 1 is a graph showing the relationship between the load and the bending angle of a flexible tube (Example 1). [Figure 11] FIG. 10 is a perspective view of a flexible tube (Example 2). [Figure 12] FIG. 12 is a side view of the flexible tube of FIG. 11 (Example 2). [Figure 13] FIG. 12 is a plan view of the flexible tube of FIG. 11 (Example 2). [Figure 14] FIG. 10 is a perspective view of a flexible tube according to a modified example (Example 2). [Figure 15] FIG. 15 is a side view of the flexible tube of FIG. 14 (Example 2). [Figure 16] FIG. 15 is a plan view of the flexible tube of FIG. 14 (Example 2). [Figure 17] FIG. 10 is a front view of a robotic forceps using a bending structure having a flexible tube (Example 3). [Figure 18] FIG. 18 is a cross-sectional view of the robotic forceps of FIG. 17 (Example 3). [Figure 19] FIG. 18 is a side view of the robotic forceps of FIG. 17 with a portion thereof omitted (Example 3). [Figure 20] FIG. 20 is a perspective view of the robotic forceps of FIG. 19 with a portion thereof further omitted (Example 3). [Figure 21] FIG. 21 is a side view of the robotic forceps of FIG. 20 (Example 3). [Figure 22] FIG. 22 is a plan view of the robotic forceps of FIG. 21 (Example 3). [Figure 23] 1A and 1B are cross-sectional views of a bent structure, in which (A) shows the structure in a normal state and (B) shows the structure in a bent state (Example 3). [Figure 24] 10 is a graph showing the relationship between the load and the bending angle of the bending structure (Example 3). [Figure 25] FIG. 11 is a perspective view of a robotic forceps using a bending structure with a portion thereof omitted (Example 4). [Figure 26] FIG. 26 is a side view of the robotic forceps of FIG. 25 (Example 4). [Figure 27] FIG. 26 is a cross-sectional view of the robotic forceps of FIG. 25 (Example 4). [Figure 28] FIG. 10 is a plan view of an elastic member according to a modified example (Example 4). [Figure 29] FIG. 10 is a plan view of an elastic member according to another modified example (Example 4). [Figure 30] FIG. 11 is a perspective view of a robotic forceps using a bending structure with a portion thereof omitted (Example 5). [Figure 31] FIG. 31 is a side view of the robotic forceps of FIG. 30 (Example 5). [Figure 32] FIG. 31 is a cross-sectional view of the robotic forceps of FIG. 30 (Example 5). [Figure 33] FIG. 31 is a perspective view of an elastic member used in the bending structure of FIG. 30 (Example 5). DETAILED DESCRIPTION OF THE INVENTION

[0014] The goal of achieving compactness while also providing excellent load-bearing capacity and flexibility was achieved by using a flexible tube in which the main body is constructed by stacking multiple wave washers, and which can be bent by the expansion and contraction of each wave washer in the axial direction.

[0015] Each wave washer preferably has a plurality of peaks and valleys in the circumferential direction, and the peaks and valleys of adjacent wave washers preferably abut against each other. In this case, the stacked state of the wave washers can be maintained by fixing the peaks and valleys of adjacent wave washers together.

[0016] Preferably, the plurality of wave washers have insertion holes through which the drive wire passes. In this case, the stacked state of the wave washers may be maintained by positioning the drive wire between adjacent wave washers without fixing the peaks and valleys of the adjacent wave washers together.

[0017] Alternatively, a bending structure may be formed by providing an elastic member inside the flexible tube. The elastic member is disposed inside the main body of the flexible tube, has higher axial rigidity than the main body, and is bendable in response to bending of the main body.

[0018] The elastic member may have various shapes, such as a coil spring located at the axial center of the main body, a solid column, or a hollow cylinder. [Example]

[0019] [Structure of robotic forceps] FIG. 1 is a perspective view showing a robotic forceps having a flexible tube according to a first embodiment of the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a cross-sectional view of the same.

[0020] The robotic forceps 1 constitutes the tip of a robotic arm of a surgical robot, which is a medical manipulator, and is an example of a medical manipulator.

[0021] The medical manipulator to which the flexible tube 3 can be applied is not particularly limited as long as it is operated by hand by a doctor or the like, regardless of whether it is attached to a surgical robot or not, and has a bending portion that performs bending operations.

[0022] Therefore, medical manipulators also include endoscopic cameras and manual forceps that are not attached to surgical robots.

[0023] The robotic forceps 1 of this embodiment is composed of a shaft portion 5, a bending portion 7, and a gripping unit 9.

[0024] The shaft portion 5 is formed, for example, in a cylindrical shape. A drive wire 11 for driving the bending portion 7 and a push-pull cable 13 for driving the gripping unit 9 run through the shaft portion 5. The gripping unit 9 is provided at the tip of the shaft portion 5 via the bending portion 7.

[0025] The drive wire 11 may be any cord-like member, and is not particularly limited to, for example, a twisted wire, a NiTi (nickel titanium) single wire, a piano wire, an articulated rod, a chain, a string, a thread, a rope, etc.

[0026] The bending portion 7 is formed by the flexible tube 3 of this embodiment. The driving wire 11 and the push-pull cable 13 pass through the bending portion 7 (flexible tube 3) in the axial direction, and the bending portion 7 (flexible tube 3) is bendable in response to the operation of the driving wire 11. The axial direction means the direction along the axis of the flexible tube 3, and does not necessarily have to be strictly parallel to the axis, but also includes a direction slightly inclined relative to the axis.

[0027] The push-pull cable 13 is provided at the axial center of the bending portion 7 (flexible tube 3). In this embodiment, four drive wires 11 are provided at 90-degree intervals in the circumferential direction, and each is disposed so as to be biased radially outward relative to the push-pull cable 13. Details of the flexible tube 3 will be described later. The radial direction means the radial direction of the flexible tube 3.

[0028] The gripping unit 9 has a pair of gripping portions 9b pivotally supported so as to be openable and closable on a base portion 9a attached to the tip of the bending portion 7. A driving wire 11 passing through the bending portion 7 is connected to the base portion 9a.

[0029] Therefore, by operating the drive wire 11, the gripping unit 9 can bend the bending portion 7 and orient the gripping portion 9b in a desired direction.

[0030] The gripping portion 9b has a groove 9c that is inclined relative to the axial direction when the gripping portion 9b is closed. A protrusion 9e of a movable piece 9d is slidably engaged with the groove 9c of the gripping portion 9b. The movable piece 9d is arranged axially movable within a through-hole 9f in the base 9a of the gripping unit 9, and is connected to a push-pull cable 13 that passes through the bending portion 7.

[0031] Therefore, the gripping portion 9b is opened and closed by the moving piece 9d moving in the axial direction in response to the forward and backward movement (push-pull movement) of the push-pull cable 13. Note that the driving of the gripping unit 9 that opens and closes the gripping portion 9b is not limited to the push-pull cable 13, and an air tube or multiple drive cables may also be used.

[0032] [Flexible tube structure] Fig. 4 is a perspective view of the robotic forceps 1 of Fig. 1 with some parts omitted. Fig. 5 is a perspective view of the robotic forceps 1 with some parts of Fig. 4 further omitted, Fig. 6 is a side view of the same, Fig. 7 is a perspective view showing the flexible tube 3, Fig. 8(A) is a side view of the same, and Fig. 8(B) is an enlarged view of part VIII of Fig. 8(A). Fig. 9 is a cross-sectional view of the flexible tube 3, with Fig. 9(A) showing it in its normal state and Fig. 9(B) showing it in its bent state. Fig. 8 shows Fig. 7 as viewed from a 45° direction (diagonally downward right of Fig. 7), and Fig. 9 shows a cross-section passing through the insertion hole 17d located in the left-right direction of Fig. 7 as viewed from the front in the depth direction of Fig. 7.

[0033] 1 to 9, the flexible tube 3 serves as the bending portion 7 of the robotic forceps 1 and elastically supports the gripping unit 9 relative to the shaft portion 5. The flexible tube 3 of this embodiment has a main body portion 15 formed with an insertion hole 17d.

[0034] The main body 15 is formed by stacking a plurality of wave washers 17 in the axial direction, and is bendable by the expansion and contraction of each wave washer 17 in the axial direction.

[0035] Each wave washer 17 is formed into an annular shape from metal, ceramics, or the like. In this embodiment, the wave washer 17 is formed into an annular shape from stainless steel, and the radial width between the inner and outer peripheries is constant. The shape, material, etc. of the wave washer 17 can be changed as appropriate depending on the characteristics required of the flexible tube 3.

[0036] Each wave washer 17 has a plurality of peaks 17a in the circumferential direction, and a valley 17b between adjacent peaks 17a. The wave washer 17 of this embodiment has two peaks 17a that face each other in the radial direction, and two valleys 17b that face each other in the radial direction between the peaks 17a. Therefore, in this embodiment, the peaks 17a and the valleys 17b are alternately arranged every 90 degrees in the circumferential direction.

[0037] The number of peaks 17a and valleys 17b can be changed as appropriate depending on the characteristics required of the flexible tube 3.

[0038] The peaks 17a and valleys 17b are curved in opposite arcs in the axial direction and are provided from the outer periphery to the inner periphery of the wave washer 17. Between adjacent wave washers 17 in the axial direction, the peaks 17a of one wave washer 17 abut against the valleys 17b of the other wave washer. The expansion and contraction of these peaks 17a and valleys 17b allows each wave washer 17 to elastically expand and contract in the axial direction.

[0039] The abutting peaks 17a and valleys 17b are fixed by suitable means such as welding, adhesive, etc. This allows the main body 15 of the flexible tube 3 to be maintained in a stacked state.

[0040] It should be noted that even if the abutting peaks 17a and valleys 17b are not fixed, the stacked state of the wave washers 17 can be maintained by inserting the drive wire 11 into an insertion hole 17d, which will be described later.

[0041] The peaks 17a and valleys 17b do not have to be in contact with each other, and may be in contact with the inclined portions 17c, for example, slightly offset from each other in the circumferential direction.

[0042] In each wave washer 17, the peaks 17a and valleys 17b are connected by inclined portions 17c. The inclined portions 17c are inclined radially and slightly twisted between the inner and outer peripheries. An insertion hole 17d is provided in the inclined portions 17c as a through-hole. The curvature radii of the peaks 17a and valleys 17b, the inclination angle and twist of the inclined portions 17c, etc. can be changed as appropriate depending on the characteristics required of the flexible tube 3.

[0043] A plurality of insertion holes 17d are provided in each inclined portion 17c in the circumferential direction of the main body portion 15. In this embodiment, four drive wires 11 are provided at 90-degree intervals in the circumferential direction, and accordingly, four insertion holes 17d are provided at 90-degree intervals in the circumferential direction of each inclined portion 17c. However, the number of insertion holes 17d can be changed depending on the number of drive wires 11.

[0044] Between the inclined portions 17c of the wave washers 17 adjacent in the axial direction, the insertion holes 17d communicate with each other in the axial direction, and the drive wire 11 is inserted through these communicating insertion holes 17d. This insertion allows the flexible tube 3 to function as a guide that passes the drive wire 11 in the axial direction as a through portion and holds it in a predetermined position.

[0045] Instead of the insertion hole 17d, the through-portion may be a notch or recess that is recessed radially from the outer or inner periphery of the main body 15 of the flexible tube 3. Therefore, the driving wire 11 can be passed through the flexible tube 3 in the axial direction while being aligned with the through-portion, such as a recess on the inner or outer periphery.

[0046] Each insertion hole 17d is located at the middle of the radial width of the wave washer 17. However, the insertion holes 17d may be biased radially inward or outward from the middle of the radial width. The radial distance of each insertion hole 17d from the axis of the main body 15 can be set appropriately depending on the characteristics of the flexible tube 3, and may be, for example, constant or not constant.

[0047] The shape of the insertion hole 17d is substantially circular and is larger than the diameter of the drive wire 11. This difference in diameter allows the inclination and displacement of the inclined portion 17c. Note that the shape of the insertion hole 17d is not limited to a circle and may be other shapes such as a rectangle.

[0048] The main body 15 is provided between the first and second connecting portions 19 and 21. The first and second connecting portions 19 and 21 respectively constitute the tip of the shaft portion 5 of the robotic forceps 1 and a part of the base portion 9a of the grasping unit 9, and are cylindrical and made of resin, metal, or the like.

[0049] The drive wire 11 is inserted in the axial direction through a through hole (not shown) in the first coupling part 19. The tip of the drive wire 11 is fixed in a fixing hole (not shown) in the second coupling part 21. A cable insertion hole 19b is provided in the axial center of the first coupling part 19, and the push-pull cable 13 is inserted through this cable insertion hole 19b.

[0050] [Flexible tube operation] When a doctor operates the robotic forceps 1, the flexible tube 3 serving as the bending portion 7 bends at the movable side located on the gripping unit 9 side relative to the fixed side located on the shaft portion 5 side by pulling any one of the drive wires 11. By pulling several drive wires 11 in combination, the flexible tube 3 can be bent in all directions, 360 degrees.

[0051] When one of the drive wires 11 is pulled and bent, the peaks 17a and valleys 17b of the flexible tube 3 are compressed on the inner side of the bend relative to the neutral axis, and the peaks 17a and valleys 17b of the flexible tube 3 are stretched on the outer side of the bend, as shown in Fig. 9(B). By deforming in this manner, the inclined portions 17c through which the manipulated drive wire 11 is inserted come closer to each other, and the flexible tube 3 is bent as a whole.

[0052] Furthermore, when bending, the flexible tube 3 maintains the driving wire 11 at an appropriate position by passing it through the insertion hole 17d, so that the flexible tube 3 can be stably and accurately bent in response to the doctor's operation.

[0053] [Load-bearing capacity and flexibility] FIG. 10 is a graph showing the relationship between the load and the bending angle of the flexible tube 3 according to the first embodiment.

[0054] FIG. 10 plots the load when the flexible tube 3 is bent from a bending angle of 0 degrees to 90 degrees.

[0055] As shown in FIG. 10, the load characteristics of the load and flexion angle show high linearity of the increase in load relative to the increase in flexion angle from 0° to 90°.

[0056] Therefore, the flexible tube 3 of this embodiment has excellent load resistance and flexibility.

[0057] [Effects of Example 1] As described above, the flexible tube 3 of this embodiment is made up of a plurality of wave washers 17 that are stacked in the axial direction and maintained in that stacked state, and has a main body portion 15 that can be bent by expanding and contracting in the axial direction.

[0058] As a result, in this embodiment, the linearity of the load characteristics between the bending angle and the load can be increased, and a flexible tube 3 that is compact and has excellent load resistance and flexibility can be obtained.

[0059] As a result, the flexible tube 3 can be stably and accurately bent in response to the operation of the doctor.

[0060] Each wave washer 17 has a plurality of peaks 17a and valleys 17b between the peaks 17a in the circumferential direction, and the peaks 17a and valleys 17b of adjacent wave washers 17 abut against each other.

[0061] Therefore, in the flexible tube 3 of this embodiment, the bending operation can be reliably performed by the expansion and contraction of the peaks 17a and valleys 17b.

[0062] Furthermore, in this embodiment, the peaks 17a and valleys 17b of adjacent wave washers 17 are fixed together, so that the stacked state of the wave washers 17 with their peaks 17a and valleys 17b in contact can be reliably maintained, and the flexible tube 3 can be more reliably bent.

[0063] Furthermore, in this embodiment, since the contacting peaks 17a and valleys 17b are fixed to each other, it is possible to provide excellent torsional rigidity.

[0064] Furthermore, in this embodiment, since the multiple wave washers 17 have insertion holes 17d through which the drive wire 11 is inserted, the main body 15 can be used as a guide for the drive wire 11, holding the drive wire 11 in an appropriate position and enabling more stable and accurate bending operations. [Example]

[0065] Fig. 11 is a perspective view showing a flexible tube according to a second embodiment of the present invention, Fig. 12 is a side view of the same, and Fig. 13 is a plan view of the same. In the second embodiment, the same reference numerals are used to designate components corresponding to those in the first embodiment, and redundant explanations will be omitted.

[0066] The flexible tube 3 of this embodiment is different from that of the first embodiment in that the planar shape of the wave washer 17 of the main body 15 is changed. The other parts have the same shape as the first embodiment.

[0067] Each wave washer 17 of the main body 15 has a regular octagonal outer periphery. The peaks 17a and valleys 17b are provided from the middle of the corresponding sides of the regular octagon to the inner periphery. The inner periphery of the wave washer 17 has a circular shape, similar to that of the first embodiment.

[0068] FIG. 14 is a perspective view showing a flexible tube 3 according to a modified example, FIG. 15 is a side view of the same, and FIG. 16 is a plan view of the same.

[0069] In the modified flexible tube 3, the outer periphery of each wave washer 17 of the main body 15 also has a regular octagonal shape. However, the peaks 17a and valleys 17b are provided from the corners of the corresponding regular octagon to the inner periphery.

[0070] In this embodiment and the modified example, the same effects as those of the first embodiment can be achieved. [Example]

[0071] Fig. 17 is a front view showing robotic forceps using a bending structure having a flexible tube according to Example 3 of the present invention, Fig. 18 is a cross-sectional view of the same, Fig. 19 is a side view of the robotic forceps in Fig. 17 with a portion thereof omitted, Fig. 20 is a perspective view of the robotic forceps with a further portion thereof omitted, Fig. 21 is a side view of the same, and Fig. 22 is a plan view of the same. Fig. 23 is a cross-sectional view of the bending structure, with Fig. 23(A) showing the bending structure in a normal state and Fig. 23(B) showing the bending structure in a bent state. Note that in Example 3, components corresponding to those in Example 1 are designated by the same reference numerals, and redundant explanations will be omitted.

[0072] In this embodiment, a bending structure 25 is configured by disposing an elastic member 23 inside the flexible tube 3 of the first embodiment.

[0073] The elastic member 23 is a metal coil spring, particularly a close-contact coil spring. A close-contact coil spring is a coil spring in which the coils are in close contact with each other in a free state. However, a non-close-contact coil spring having gaps between the coils in a free state can also be used as the elastic member 23.

[0074] In the elastic member 23 of this embodiment, the cross section of the wire of the coil spring is circular, but the cross section of the wire of the coil spring may be other shapes such as rectangular or elliptical.

[0075] The elastic member 23 is disposed at the axial center of the flexible tube 3, and has a cable insertion hole 23a defined on the inner periphery thereof for inserting the push-pull cable 13. The outer periphery of the elastic member 23 has a gap with respect to the inner periphery of the flexible tube 3.

[0076] In the axial direction, the elastic member 23 stretches over at least the entire area of ​​the main body 15 of the flexible tube 3, and has a higher rigidity against compression than the flexible tube 3. This makes it possible for the elastic member 23 to prevent the flexible tube 3 from being inadvertently compressed in the axial direction.

[0077] Furthermore, the elastic member 23 is bendable in accordance with the flexible tube 3, and has the function of adjusting the load characteristics of the flexible tube 3 in accordance with the load characteristics in the bending direction.

[0078] FIG. 24 is a graph showing the relationship between the load and the bending angle of the bending structure 25 according to Example 3 and the comparative example.

[0079] As a comparative example, the relationship between the load and the bending angle of the flexible tube 3 of Example 1 is shown. In Example 3, similar to Example 1, the bending structure 25 is bent from 0 degrees to 90 degrees, and the load when the bending angle returns to 0 degrees is plotted.

[0080] As shown in FIG. 24, Example 3 has high linearity and is excellent in load resistance and flexibility.

[0081] As described above, the bending structure 25 of this embodiment is arranged within the main body portion 15 of the flexible tube 3, and is equipped with an elastic member 23 that has higher axial rigidity than the main body portion 15 and can bend in response to the bending of the flexible tube 3.

[0082] Therefore, the bending structure 25 of this embodiment can prevent the flexible tube 3 from being compressed inadvertently.

[0083] Therefore, if the flexible tube 3 is inadvertently compressed, the behavior of the bending portion 7 due to the operation of the drive wire 11 may become unstable, but in this embodiment, such unstable behavior can be suppressed. Furthermore, since the path length does not change even when bending, the operation of the gripping unit 9 is stable.

[0084] Furthermore, the bending structure 25 of this embodiment can adjust the load characteristics of the flexible tube 3 by adjusting the load characteristics of the elastic member 23 in the bending direction.

[0085] In addition, this embodiment also has the same effects as the first embodiment.

[0086] The elastic member 23 can also be applied to the second embodiment. [Example]

[0087] Fig. 25 is a perspective view with a portion thereof omitted of a robotic forceps using a bending structure according to Example 4 of the present invention, Fig. 26 is a side view of the same, and Fig. 27 is a cross-sectional view of the same. Note that in Example 4, the same reference numerals are used to designate components corresponding to those in Example 3, and redundant explanations will be omitted.

[0088] The bending structure 3 of this embodiment has a solid columnar elastic member 23. The rest of the structure is the same as that of the third embodiment.

[0089] That is, the elastic member 23 is formed into a solid column shape from an elastic material such as rubber, etc. This gives the elastic member 23 a higher axial rigidity than the main body 15 of the flexible tube 3 and allows it to bend in response to bending of the flexible tube 3.

[0090] In this embodiment, since the solid columnar elastic member 23 is located at the axial center of the flexible tube 3, the gripping unit 9 may be driven by a plurality of drive wires or the like instead of the push-pull cable 13.

[0091] FIG. 28 is a plan view showing an elastic member 23 according to a modified example, and FIG. 29 is a plan view showing an elastic member 23 according to another modified example.

[0092] 28, a radially recessed groove 23b is provided on the outer periphery of a solid columnar elastic member 23. Groove 23b is provided along elastic member 23 in the axial direction and guides drive wire 24, which is used in place of push-pull cable 13, for driving grip portion 9.

[0093] The number and arrangement of the drive wires 24 are changed as appropriate depending on the structure of the grip portion 9, and the number and arrangement of the grooves 23b are also changed as appropriate accordingly.

[0094] 29, a concave slit 23c is provided in the radial direction from the outer periphery to near the axial center of a solid columnar elastic member 23. The slit 23c is provided along the axial direction of the elastic member 23, and guides the push-pull cable 13 at the axial center of the elastic member 23.

[0095] As shown by the two-dot chain line, the slit 23c may be configured so that the diameter from the outer periphery of the elastic member 23 to just before the axial center is slightly narrower than the diameter of the push-pull cable 13, and the diameter at the axial center is the same as that of the push-pull cable 13. The slit 23c may also be provided beyond the axial center of the elastic member 23.

[0096] The fourth embodiment and the modified example thereof can also achieve the same effects as those of the third embodiment. [Example]

[0097] Fig. 30 is a perspective view showing a bending structure according to Example 5 of the present invention, Fig. 31 is a side view of the same, and Fig. 32 is a cross-sectional view of the same. Fig. 33 is a perspective view showing an elastic member of the bending structure of Fig. 30. In Example 5, the same reference numerals are used to designate components corresponding to those in Example 3, and redundant explanations will be omitted.

[0098] The bending structure 3 of this embodiment has a hollow cylindrical elastic member 23. The rest of the structure is the same as that of the third embodiment.

[0099] The elastic member 23 is made of a superelastic alloy and is configured with end tube portions 27a, 27b, a ring portion 29, tube coupling portions 31a, 31b, and a tube slit 33. The superelastic alloy may be a titanium-based alloy such as a NiTi alloy (nickel-titanium alloy) or GUM METAL (registered trademark), a Cu-Al-Mn alloy (copper-based alloy), or an Fe-Mn-Al alloy (iron-based alloy).

[0100] The cylindrical end portions 27a and 27b are ring-shaped and provided at both ends, and a plurality of ring portions 29 are positioned between the cylindrical end portions 27a and 27b.

[0101] The multiple ring portions 29 are arranged in parallel and at equal intervals in the axial direction. The axial width of the ring portions 29 is constant in this embodiment. However, the axial width of the ring portions 29 can also be gradually reduced from the fixed side located on the shaft portion 5 side toward the movable side located on the gripping unit 9 side.

[0102] Adjacent ring portions 21 are joined at a portion in the circumferential direction by tube joining portions 31a, 31b. Ring portions 29 at both ends are joined to end cylindrical portions 27a, 27b by tube joining portions 31a, 31b.

[0103] The tube connecting portions 31a, 31b are provided integrally with the ring portion 29, and connect the ring portions 29 adjacent in the axial direction at two circumferential locations that are radially opposed to each other.

[0104] In each ring portion 29, the tube coupling portions 31a, 31b located on one axial side (base end side) and the tube coupling portions 31a, 31b located on the other axial side (tip end side) are arranged circumferentially offset by 180 / N degrees.

[0105] The misalignment between the tube coupling portions 31a and 31b here refers to the misalignment between the center lines of the tube coupling portions 31a and 31b (the same applies hereinafter). N is an integer equal to or greater than 2. In this embodiment, N=2, and the tube coupling portions 31a and 31b are arranged with a 90-degree misalignment.

[0106] The offset between the tube connecting portions 31a and 31b can be set to 60 degrees or the like, but it is preferable to set it to 90 degrees. This is because it reduces the number of ring portions 29 required to bend the flexible tube 3, thereby making it possible to make the overall length compact.

[0107] Each of the tube coupling portions 31a, 31b has a rectangular plate shape extending in the axial direction and has a slight curvature corresponding to the ring portion 29. The circumferential width of the tube coupling portions 31a, 31b is constant in this embodiment, but it is also possible to gradually decrease the width from the fixed side located on the shaft portion 5 side toward the movable side located on the gripping unit 9 side.

[0108] When the circumferential width of the tube coupling portions 31 a, 31 b is gradually reduced toward the movable side, the axial width of the ring portion 29 may be made smaller than the circumferential width of the largest tube coupling portion 31 a, 31 b. In this case, it is preferable that the circumferential width of the smallest tube coupling portion 31 a, 31 b and the axial width of the ring portion 29 are the same.

[0109] Both axial ends of the tube coupling portions 31a, 31b transition to the ring portion 29 via the arc portions 35. This provides a tangential continuity between the tube coupling portions 31a, 31b and the ring portion 29.

[0110] In the radial direction of the ring portion 29, there is no step between the inner periphery and the outer periphery of the tube coupling portions 31a, 31b and the ring portion 29. However, it is also possible to form the tube coupling portions 31a, 31b so that they are thicker or thinner than the ring portion 29 and have a step.

[0111] The tube coupling portions 31a and 31b bend so that one circumferential side is compressed and the other side is expanded around the neutral axis, thereby enabling bending of the flexible tube 3. In this embodiment, the tube coupling portions 31a and 31b, which are offset by 90 degrees in the circumferential direction, bend, allowing bending in two different intersecting directions.

[0112] Tube slits 33 are provided on both circumferential sides of each of the tube coupling portions 31a, 31b to allow bending of the flexible tube 3 due to bending of the tube coupling portions 31a, 31b.

[0113] That is, the tube slits 33 are defined on both circumferential sides of the tube coupling portions 31a, 31b between axially adjacent ring portions 29. Each tube slit 33 has a rectangular shape with rounded corners according to the shapes of the ring portions 29 and the tube coupling portions 31a, 31b.

[0114] With this configuration, the elastic member 23 of this embodiment has a higher axial rigidity than the main body 15 of the flexible tube 3 and is bendable in response to bending of the flexible tube 3.

[0115] Therefore, the fifth embodiment can also achieve the same effects as the third embodiment.

[0116] Furthermore, in Example 5, the elastic member 23 made of a superelastic alloy is formed by connecting multiple ring portions 29 in the axial direction by tube connecting portions 31 a, 31 b, and is configured so that bending is possible by bending the tube connecting portions 31 a, 31 b, thereby achieving a compact structure with excellent load resistance and flexibility. Based on this characteristic, in this example, the characteristics of the entire bending structure 25 can be improved.

[0117] Furthermore, the elastic member 23 can have excellent torsional rigidity by connecting the ring portions 29 with the tube connecting portions 31a and 31b, thereby improving the torsional rigidity of the bending structure 25 in this embodiment. [Explanation of symbols]

[0118] 1 Robotic forceps (medical manipulator) 3 Flexible Tube 11 Drive wire 15 Main body 17 Wave Washer 17a Mountain 17b Tanibe 17c Slope 17d Insertion hole 23 Elastic member 25 Bent structure

Claims

1. A flexible tube through which a drive wire of a medical manipulator passes in an axial direction along an axis and which is bent in response to operation of the drive wire, a bendable main body having a plurality of wave washers stacked in the axial direction and maintained in a stacked state; Each wave washer includes a plurality of circumferentially extending peaks that are convex on one side in the axial direction and concave on the other side in the axial direction, valleys between the peaks that are concave on one side in the axial direction and convex on the other side in the axial direction, inclined portions that are located between adjacent peaks and valleys in the circumferential direction and that are inclined so as to extend from the adjacent peaks to the valleys with respect to the axial direction when viewed from the outside in the radial direction in a normal state when not bent, and through portions that are provided only in the inclined portions and through which the drive wire is passed in the axial direction. A flexible tube characterized by:

2. The flexible tube according to claim 1, The adjacent wave washers are fixed to each other at the abutting peaks and valleys. A flexible tube characterized by:

3. The flexible tube according to claim 1 or 2, The through portion is an insertion hole. A flexible tube characterized by:

4. A bending structure including the flexible tube according to any one of claims 1 to 3, an elastic member disposed within the main body portion and having a higher rigidity in the axial direction than the main body portion and capable of bending in response to bending of the flexible tube; A bent structure characterized by:

5. 5. The bending structure according to claim 4, The elastic member is a coil spring, a solid columnar body, or a hollow cylindrical body located at the axial center of the main body. A bent structure characterized by:

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