Bent structures and semi-finished products

Abstract

To provide a bent structure which can be easily returned to an extension state, and can improve performance characteristic.SOLUTION: A bent structure 1, in which a multiple flexible body 15 can displace from an extension state to a bent state, comprises: an outer coil spring 23 which constitutes the multiple flexible body 15; an inner coil spring 25 which is located inside the outer coil spring 23, and constitutes a multiple flexible body 25 in such a manner that element wires overlap in a coil radial direction between element wires of the outer coil spring 23; one side receiver component 13 which receives one end of the multiple flexible body 25; and the other side receiver component 14 which receives the other end of the multiple flexible body 15. A close contact state between the element wires of the inner and outer coil springs 25, 23 is set depending on a distance between one side receiver component 13 and the other side receiver component 14.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a bending structure for use in a robot, a manipulator, or the like, and a semi-finished product thereof. [Background technology]

[0002] Some robots, manipulators, actuators, etc. are provided with a bending structure that allows bending and extension. An example of such a bending structure is disclosed in Patent Document 1.

[0003] The bending structure of Patent Document 1 has a double coil structure and is capable of bending and extending. This bending structure is formed by screwing an inner coil section onto the inner periphery of an outer coil section while the outer coil section is stretched, so that the wires of the outer coil section and the inner coil section are in close contact with each other.

[0004] As a result, the bent structure is in a state where an initial tension (a force that constantly tries to bring the coil wires into close contact with each other even when there is no load) is applied. Because this initial tension depends on the structure of the outer coil portion and the inner coil portion, setting a different initial tension requires changing the structure of the outer coil portion and the inner coil portion, which is cumbersome. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-26021 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved is the complicated setting of different initial tensions. [Means for solving the problem]

[0007] The present invention provides a bending structure in which multiple flexible bodies can be bent from an extended state to a bent state, the bending structure comprising: an outer coil spring constituting the multiple flexible bodies; an inner coil spring arranged inside the outer coil spring and constituting the multiple flexible bodies with wires overlapping between the wires of the outer coil spring in a coil radial direction; a one-side support member that supports one side of the multiple flexible bodies; and a other-side support member that supports the other side of the multiple flexible bodies. a plurality of cord-like members, one side of which is fixed to the one-side support member and the other side of which is routed through the other-side support member, for manipulating displacement of the multiple flexible bodies into a bent state; and an operating unit, which is provided on the other side of the cord-like members and which operates displacement of the multiple flexible bodies between an extended state and a bent state by relatively pulling and pulling back the plurality of cord-like members. , The plurality of cord-like members are pulled toward the other-side receiving member without operation of the operating portion, The distance between the one-side support member and the other-side support member Adjust When the multiple flexible bodies are stretched, the wires of the inner coil spring and the outer coil spring are in close contact with each other. of setting vinegar R Closely set part and , Equipped with A flexure structure is provided. [Effects of the Invention]

[0009] According to the present invention, different initial tensions can be easily set by setting the tight contact state between the wires of the inner coil spring and the outer coil spring in accordance with the distance between the one-side receiving member and the other-side receiving member. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing a main part of a manipulator to which a bending structure according to a first embodiment of the present invention is applied. [Figure 2] FIG. 2 is a cross-sectional view of the manipulator of FIG. [Figure 3] FIG. 3 is a schematic diagram showing the main part of FIG. [Figure 4] 4(A) and (B) are conceptual diagrams of the manipulator of FIG. 1, with FIG. 4(A) showing the state before initial tension is applied, and FIG. 4(B) showing the state after initial tension is applied. [Figure 5] 5(A) and (B) are conceptual diagrams of the manipulator of FIG. 1, with FIG. 5(A) showing the extended state and FIG. 5(B) showing the bent state. [Figure 6]Figures 6(A) and (B) show a comparison of the return characteristics of the bending structure from a bent state to an extended state with a comparative example, where Figure 6(A) is a graph showing the overall change, and Figure 6(B) is a graph enlarging the area near the origin of Figure 6(A). [Figure 7] 7(A) and (B) are conceptual diagrams of a manipulator to which a bending structure according to Example 2 of the present invention is applied, with FIG. 7(A) showing the extended state and FIG. 7(B) showing the bent state. [Figure 8] FIG. 8 is a conceptual diagram showing a manipulator to which a bending structure according to a third embodiment of the present invention is applied. [Figure 9] FIG. 9 is a conceptual diagram showing a manipulator to which a bending structure according to a fourth embodiment of the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention achieves the object of easily setting different initial tensions by setting the tight contact state between the wires of the inner coil spring and the outer coil spring in accordance with the distance between the one-side support member and the other-side support member.

[0012] That is, the bending structure 1 has multiple flexible bodies 15 that can be bent from an extended state to a bent state, and includes an outer coil spring 23, an inner coil spring 25, a one-side receiving member 13, and an other-side receiving member 14.

[0013] The outer coil spring 23 and the inner coil spring 25 constitute a multiple flexible body 15. The inner coil spring 25 is disposed inside the outer coil spring 23, with the wires of the inner coil spring 25 overlapping in the coil radial direction between the wires of the outer coil spring 23. The one-side receiving member 13 receives one end of the multiple flexible body 15, and the other-side receiving member 14 receives the other end of the multiple flexible body 15. The multiple flexible body 15 sets a tight contact state between the wires of the inner and outer coil springs 23 according to the distance between the one-side receiving member 13 and the other-side receiving member 14.

[0014] In the close contact state, the frictional force between the wires may be set to zero or as small as possible with respect to the restoring force that returns the multiple flexible bodies 15 from the bent state to the extended state.

[0015] The bending structure 1 may include a close contact setting portion 21 that adjusts the gap between the one-side receiving member 13 and the other-side receiving member 14 and sets the close contact state between the wires of the inner coil spring 25 and the outer coil spring 23.

[0016] The close contact setting portion 21 only needs to be able to set the close contact state between the wires of the inner and outer coil springs 23, and its structure can be freely set and realized depending on the application, etc.

[0017] The bending structure 1 is provided with a plurality of cord-like members 19, one side of which is fixed to the one-side support member 13 and the other side of which is routed through the other-side support member 14, for manipulating the displacement of the multiple flexible body 15 to a bent state, and the close contact setting section 21 may also use the cord-like members 19 to set the close contact state.

[0018] In addition, the bending structure 1 is provided with an operating unit 22 provided on the other side of the rope-like member 19, which operates the displacement between the extended state and the bent state of the multiple flexible body 15 by relative pulling and retracting operations between the multiple rope-like members 19, and the close contact setting unit 21 supports the operating unit 22 so that its position can be adjusted in the direction of the extended state of the multiple flexible body 15, and the close contact state may be set by adjusting the position of the operating unit 22 when the multiple flexible body 15 is in the extended state.

[0019] The operating unit 22 is provided with a pulley 29 that is supported on the other side receiving member 14 side and that can be rotated and moved to wrap the cord-like member 19 around the one side receiving member 13, and the close contact setting unit 21 may be provided with a tensioner 31 that adjusts the position of the pulley 29.

[0020] The close contact setting portion 21 comprises a receiving portion 33 provided on the other side of the cord-like member 19, and an elastic body 35 interposed between the other side receiving member 14 and the receiving portion 33, which applies tension to the multiple cord-like members 19 in the extended state of the multiple flexible bodies 15 relative to the one side receiving member 13, and the close contact state may be set by applying tension by the elastic body 35. [Example]

[0021] [Manipulator] FIG. 1 is a perspective view showing the main part of a manipulator according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the same, and FIG. 3 is a schematic view showing the main part of FIG.

[0022] In this embodiment, a manipulator 3 using the bending structure 1 will be described as an example. The manipulator 3 is a medical forceps that is used as forceps attached to a surgical robot, as well as an endoscopic camera not attached to a surgical robot, manual forceps, etc. The bending structure 1 can be applied to robots, manipulators, actuators, etc., and can be applied to anything that requires bending.

[0023] The manipulator 3 is composed of a shaft 5, a bending structure 1, and an end effector 7.

[0024] The shaft 5 is, for example, a cylindrical member. An end effector 7 is supported on the distal end side of the shaft 5 via a bending structure 1. The bending structure 1 will be described later.

[0025] The end effector 7 is a medical forceps, and a pair of gripping parts 7a are pivotally supported by a movable part 13 of the bending structure 1, which will be described later, so as to be able to open and close. A push-pull cable 9, which is passed through the center of the shaft 5 and the bending structure 1, is connected to the end effector 7. The gripping parts 7a are configured to open and close due to axial movement (advance and retreat movement) of this push-pull cable 9. Note that the term "axial direction" simply refers to the direction along the axis of the bending structure 1, and includes not only a direction strictly parallel to the axis but also a slightly inclined direction.

[0026] The gripping portion 7a may be driven by air, etc. The end effector 7 may also be something other than forceps, such as scissors, a gripping retractor, or a needle driver.

[0027] [Bending structure] The bending structure 1 includes an attachment base 11, a movable part 13, a fixed receiver 14, multiple flexible members 15, a drive wire 19, and a close contact setting part 21. The bending structure 1 is configured to be bendable between an extended state and a bent state. In this embodiment, the movable part 13 is a support member on one side, and the fixed receiver 14 is a support member on the other side.

[0028] Mounting base 11 is configured to pass through double coil spring 16, which is a multiple coil spring that constitutes multiple flexible body 15, and to receive one end of flexible tube 17. Mounting base 11 has fitting portion 11a and head portion 11b, and is a columnar body, particularly a stepped cylindrical body, made of resin, metal, or the like. Fitting portion 11a of mounting base 11 is fitted onto the tip of the end of shaft 5 and attached, and head portion 11b abuts against the edge of shaft 5.

[0029] The mounting base 11 only needs to be able to receive one end of the flexible tube 17 and be connected to the end of the shaft 5, and the material, shape and structure can be freely set depending on the equipment to which the bending structure 1 is applied.

[0030] The fixed receiver 14 receives the other side of the double coil spring 16, and is fitted and fixed within the end of the shaft 5. The fixed receiver 14 may also be fixed to the shaft 5 by other methods, such as welding.

[0031] The fixed receiver 14 is abutted against the fitting portion 11a of the mounting base 11 in the axial direction within the shaft 5. The fixed receiver 14 may be disposed with an axial gap from the fitting 11a. The fixed receiver 14 may also be provided integrally with the shaft 5.

[0032] The movable part 13 is a columnar body, particularly a cylindrical body, made of resin, metal, etc. The end effector 7 is attached to the movable part 13.

[0033] The movable part 13 is not limited to a columnar body, but may be a plate-like body or the like, as long as it is a member to which the end effector 7 can be attached. The movable part 13 can be formed in an appropriate shape depending on the equipment to which the bending structure 1 is applied.

[0034] The movable part 13 is connected to the mounting base 11 by the multiple flexible bodies 15. As a result, the movable part 13 constitutes a one-side support member that supports one side of the multiple flexible bodies 15. That is, the other end of the flexible tube 17 is attached to the movable part 13, and one side of the double coil spring 16 is supported thereon.

[0035] In this embodiment, the multiple flexible members 15 are arranged between the mounting base 11 and the fixed receiver 14 and the movable member 13. The multiple flexible members 15 are configured to be bendable between a bent state and an extended state in the axial direction.

[0036] This multiple flexible body 15 allows the movable part 13 to be displaced to a bent position and an extended position relative to the mounting base 11. The bent position is the position where the axis of the movable part 13 intersects with the axial direction and the bending of the bending structure 1 is at its maximum. The extended position is the position where the axis of the movable part 13 is aligned with the axial direction. In the extended position, the axis of the movable part 13 does not need to be strictly aligned with the axial direction, and a slight deviation is also included.

[0037] The multiple flexible body 15 of this embodiment is composed of a double coil spring 16 and a flexible tube 17. However, the flexible tube 17 may be omitted. Also, instead of the double coil spring 16, a multiple coil spring having three or more coils may be used.

[0038] The double coil spring 16 is a double coil that is flexible in the axial direction, and includes an outer coil spring 23 and an inner coil spring 25.

[0039] The outer coil spring 23 and the inner coil spring 25 are compression coil springs having a predetermined gap (pitch) between the wires of the springs. The outer coil spring 23 and the inner coil spring 25 are compressed between the mounting base 11 and the fixed receiver 14 with the inner coil spring 25 positioned inside the outer coil spring 23.

[0040] As a result, the inner coil spring 25 is screwed onto the inside of the outer coil spring 23. In other words, the wires of the outer coil spring 23 and the inner coil spring 25 are set in a close contact state in the extended state of the multiple flexible body 15, depending on the distance between the mounting base 11 and the fixed receiver 14. The wires of the inner coil spring 25 and the outer coil spring 23 are not in contact with each other in the free state (see FIG. 4(A)).

[0041] This compression applies a pressure to the double coil spring 16. The pressure is a force that constantly forces the wires of the inner and outer coil springs 25, 23 to come into close contact with each other.

[0042] In this embodiment, the initial tension in the close contact state is set so that the frictional force between the wires is small relative to the restoring force that returns the multiple flexible body 15 from a bent state to an extended state. In particular, in this embodiment, the frictional force between the wires in the close contact state is set to be close to zero.

[0043] In this embodiment, the restoring force of the multiple flexible bodies 15 and the frictional force between the wires are set to enable the bending structure 1 to return from a bent state to an extended state. Insofar as this is the case, it is not necessary to set the frictional force to zero.

[0044] However, the initial tension can be appropriately set by the close contact setting unit 21 depending on the equipment to which the bending structure 1 is applied.

[0045] The inner coil spring 25 has a smaller coil diameter than the outer coil spring 23 and is threadedly fitted to the inside of the outer coil spring 23. The coil diameters of the outer coil spring 23 and the inner coil spring 25 are constant from one end to the other in the axial direction. However, the coil diameter of the outer coil spring 23 can also be changed in the axial direction.

[0046] The outer coil spring 23 has a plurality of gaps separating adjacent windings in the axial direction. The windings of the inner coil spring 25 fit into these gaps from the inside. Due to this fit, the outer periphery of the wire of the inner coil spring 25 overlaps with the wire of the outer coil spring 23 in the coil radial direction.

[0047] The materials of both the outer coil spring 23 and the inner coil spring 25 can be metal, resin, or the like. The cross-sectional shape of the wire of the outer coil spring 23 and the inner coil spring 25 is circular. However, the cross-sectional shape of the outer coil spring 23 and the inner coil spring 25 is not limited to circular and may be rectangular, elliptical, or the like. The wire diameters of the outer coil spring 23 and the inner coil spring 25 may be different.

[0048] The flexible tube 17 forms the outer periphery of the multiple flexible body 15. Therefore, the flexible tube 17 contains the double coil spring 16. One end of the flexible tube 17 is connected to the movable part 13, and the other end of the flexible tube 17 is connected to the mounting base 11.

[0049] In this embodiment, the flexible tube 17 is made of a bellows. However, the flexible tube 17 may also be made of a plurality of stacked wave washers joined together by welding or the like, or may be made of a coil spring or other cylindrical body. In other words, the flexible tube 17 is not particularly limited as long as it has an elastic tubular shape.

[0050] The multiple flexible body 15 of this embodiment has a restoring force from a bent state to an extended state due to the cooperative elasticity of the flexible tube 17 and the double coil spring 16. When the flexible tube 17 is omitted, the restoring force is due to the elasticity of the double coil spring 16. Note that when the flexible tube 17 is provided, the double coil spring 16 may be configured not to generate a restoring force as the multiple flexible body 15.

[0051] The bending of the multiple flexible body 15 is performed by drive wires 19. The drive wires 19 are cord-like members made of metal or the like, and in this embodiment, are provided at four locations around the circumference of the bending structure 1, at 90-degree intervals. The drive wires 19 that face each other in the radial direction of the bending structure 1 form a pair. Therefore, in this embodiment, two pairs of drive wires 19 are provided.

[0052] However, it is possible to omit one pair of drive wires 19, and the bending structure 1 may be provided with a plurality of drive wires 19. For example, three drive wires 19 may be provided. In this case, it is preferable that the drive wires 19 are arranged every 120 degrees in the circumferential direction. The drive wires 19 can be cord-like members such as twisted wires, NiTi (nickel titanium) single wires, piano wires, articulated rods, chains, strings, threads, ropes, etc.

[0053] These drive wires 19 are adapted to bend the bending structure 1 when pulled in the axial direction, and are directly or indirectly connected to an operating mechanism (not shown) so as to be operated in the axial direction.

[0054] Note that operating in the axial direction means pulling and retracting the pair of drive wires 19 relative to one another in the axial direction. In this embodiment, when one of the pair of drive wires 19 is pulled toward the mounting base 11 relative to the movable part 13, the other is pulled back toward the movable part 13. Note that the drive wires 19 may be configured to be pulled independently of one another.

[0055] One side of each of the pair of drive wires 19 serves as a fixed portion 27 fixed to the movable portion 13. Any fixing means may be used for the fixed portion 27.

[0056] Each drive wire 19 extends from the fixed portion 27 along the axial direction, passes through the flexible tube 17, the mounting base 11 and the fixed receiver 14, and is routed at the other end through the inside of the shaft 5.

[0057] Each of the pair of drive wires 19 is connected via a pulley 29 .

[0058] The pulley 29 is supported inside the shaft 5 on the fixed receiver 14 side. This pulley 29 is linked to and operable by an operating mechanism (not shown). The drive wire 19 is pulled and pulled back by operating the pulley 29. The pulley 29 can also be supported by an operating mechanism or the like outside the shaft 5. It is also possible to omit the pulley 29 and connect each drive wire 19 to the operating mechanism.

[0059] The close contact setting unit 21 adjusts the gap between the movable unit 13 and the fixed receiver 14 when the multiple flexible bodies 15 are in an extended state, and compresses the double coil spring 16 to set a close contact state between the wires of the inner and outer coil springs 25, 23. This adjusts or sets the initial tension of the double coil spring 16.

[0060] Furthermore, in this embodiment, the initial tension of the double coil spring 16 can basically be set simply by attaching the mounting base 11 to the shaft 5. Therefore, if there is no need to adjust the gap between the movable part 13 and the fixed receiver 14, the close contact setting part 21 can be omitted. In this case, the tensioner 31, which will be described later, is omitted.

[0061] The close contact setting section 21 of this embodiment includes a plurality of cord-like members, namely, drive wires 19 and pulleys 29. As described above, one side of the drive wire 19 is fixed to the movable section 13, and the other side is routed through the fixed receiver 14, and is configured to control the displacement of the multiple flexible body 15 to a bent state. The fixed receiver 14 may have a recess or a through-hole through which the other side of the drive wire 19 passes.

[0062] The close contact setting section 21 uses the drive wire 19 in common to set the close contact state between the wires of the inner and outer coil springs 25, 23. This allows the structure to be simplified.

[0063] The pulley 29 is supported so that its position in the axial direction can be adjusted when the multiple flexible body 15 is in an extended state. By adjusting the position of the pulley 29 of this operating unit 22 when the multiple flexible body 15 is in an extended state, a tight contact state between the wires of the inner and outer coil springs 25, 23 can be established.

[0064] When the position of the pulley 29 is adjusted, the relationship between the pulley 29 and the operating mechanism is also adjusted. In a structure in which the pulley 29 is supported by the operating mechanism, the position of the operating mechanism may be supported so as to be adjustable. In a case in which the pulley 29 is omitted and each drive wire 19 is connected to the operating mechanism, the position of the operating mechanism may be adjustable.

[0065] The close contact setting unit 21 is provided with a tensioner 31 that adjusts the position of the pulley 29. The tensioner 31 adjusts the position of the pulley 29 to set the close contact state between the wires of the inner and outer coil springs 25, 23.

[0066] [Proximity Settings] 4(A) and (B) are conceptual diagrams of the manipulator of FIG. 1, with FIG. 4(A) showing the state before initial tension is applied, and FIG. 4(B) showing the state after initial tension is applied.

[0067] As shown in FIGS. 4(A) and 4(B), a semi-finished product of the bending structure 1 before the application of initial tension is attached to the end of the shaft 5, and an initial tension is applied to the double coil spring 16.

[0068] As shown in Fig. 4(A), the semi-finished product of the bending structure 1 includes an outer coil spring 23, an inner coil spring 25, and a movable part 13. In this semi-finished product of the bending structure 1, the inner coil spring 25 and the outer coil spring 23 of the double coil spring 16 are sparse, and gaps exist between the wires in the axial direction.

[0069] That is, the wires of the inner coil spring 25 and the outer coil spring 23 are not in close contact with each other, and the wires of the inner coil spring 25 overlap in the coil radial direction of the outer coil spring 23. Note that in the semi-finished product of the bent structure 1, the wires of the inner coil spring 25 and the outer coil spring 23 may be in close contact with each other.

[0070] In this state, the end of double coil spring 16 passing through mounting base 11 is brought into contact with fixed receiver 14, and fitting portion 11a of mounting base 11 is joined to the end of shaft 5. This reduces the gap between movable portion 13 and fixed receiver 14, compressing double coil spring 16.

[0071] As a result, as shown in Figure 4(B), double coil spring 16 is compressed in accordance with the gap between movable part 13 and fixed receiver 14, and the wires of inner coil spring 25 and outer coil spring 23 come into close contact with each other. As a result, initial tension is applied to double coil spring 16.

[0072] In addition, in the semi-finished product of the bending structure 1, when the wires of the inner coil spring 25 and the outer coil spring 23 are in close contact with each other, an initial tension is applied and adjusted by compressing the double coil spring 16 according to the distance between the movable part 13 and the fixed receiving body 14.

[0073] If further adjustment of the initial tension is required in this state, the close contact setting unit 21 adjusts the gap between the fixed receiver 14 and the movable unit 13 while the double coil spring 16 is in an extended state. In other words, the position of the movable unit 13 is adjusted by pulling the pulley 29 with the tensioner 31. This adjustment further compresses the double coil spring 16, adjusting the close contact between the wires of the inner and outer coil springs 25, 23.

[0074] Therefore, in this embodiment, it is possible to apply a highly accurate initial tension to the double coil spring 16. If it is desired to adjust the initial tension beyond the settable range of the close contact setting portion 21, the position of the fixed receiver 14 can be changed.

[0075] When the mounting base 11 abuts against the fixed receiving body 14, the wires of the inner and outer coil springs 25, 23 are just about to come into close contact, and from this state, the position of the pulley 29 can be further adjusted to set the close contact state.

[0076] Alternatively, a gap may be provided between the mounting base 14 and the fixed receiving body 14, and the wires of the inner and outer coil springs 25, 23 may be brought into close contact with each other by adjusting the position of the pulley 29.

[0077] In this way, in this embodiment, the tight contact state between the wires of the inner coil spring 25 and the outer coil spring 23 can be set according to the distance between the movable part 13 and the fixed receiving body 14, and different initial tensions can be easily set.

[0078] [Operation] 5(A) and (B) are conceptual diagrams of the manipulator of FIG. 1, with FIG. 5(A) showing the extended state and FIG. 5(B) showing the bent state.

[0079] When an operator such as a doctor operates the manipulator 3, the bending structure 1 is bent by pulling any one of the drive wires 19. The bending structure 1 can be bent in all directions by pulling different pairs of drive wires 19 in combination. This allows the end effector 7 to be oriented in a desired direction.

[0080] After bending the bending structure 1, the friction force between the wires of the inner coil spring 25 and the outer coil spring 23 is set to be smaller than the restoring force of the double coil spring 16, so that the bending structure 1 can be reliably restored.

[0081] Figures 6(A) and (B) show a comparison of the return characteristics of the bending structure from a bent state to an extended state with a comparative example, where Figure 6(A) is a graph showing the overall change, and Figure 6(B) is a graph enlarging the area near the origin of Figure 6(A).

[0082] In Figure 6, Example (1N) is an example in which a load of 1N per drive wire 19 is applied in the axial direction to double coil spring 16 of an example in which there are gaps between the wires as in Figure 4(A), and the close contact load between the wires is nearly zero, resulting in a close contact state. Example (3N) is an example in which a load of 3N per drive wire 19 is applied in the axial direction to double coil spring 16 of an example in which the close contact load between the wires is nearly zero, resulting in a close contact state, when a load of 1N per drive wire 19 is applied in the axial direction.

[0083] In Figure 6, Comparative Example (1N) is an example in which a load of 1N per drive wire is applied in the axial direction to a double coil spring in which an inner coil spring and an outer coil spring are screwed together and each spring is made of a tension coil with no gaps between the wires. Comparative Example (3N) is an example in which a load of 3N per drive wire is applied in the axial direction to a double coil spring in which an inner coil spring and an outer coil spring are screwed together and each spring is made of a tension coil.

[0084] These springs were attached to φ5 forceps, and a bending load was applied to displace them from an extended state to a flexed state. The load was then removed to compare whether or not they returned to the original extended state.

[0085] In Figure 6, the vertical axis represents the displacement of the end effector, and the horizontal axis represents the bending angle of the bending structure 1. For the same spring, two lines are displayed, one above the other; the upper line represents the change data from the extended state to the bent state, and the lower line represents the restoration data from the bent state to the extended state.

[0086] As shown in Figure 6(B), in the comparative examples (1N) and (3N), even after the bending load was removed, the interlinear friction exceeded the restoring force during the return to the extended state, and neither of the bending angles returned to the origin of zero.

[0087] In contrast to this, in both Example (1N) and Example (3N), the interlinear friction was lower than the restoring force until the knee returned to the extended state, and the bending angle returned to the origin of zero.

[0088] Therefore, in this embodiment, by setting the wires in a tight contact state so that the frictional force between the wires is small and opposes the restoring force that returns the multiple flexible body 15 from a bent state to an extended state, the multiple flexible body 15 that has been bent can be reliably restored to the origin of the extended state.

[0089] Furthermore, since the initial load can be ignored even during times other than the restoration time, this contributes to the compression resistance of the double coil spring 16. [Example]

[0090] 7(A) and (B) are conceptual diagrams of a manipulator to which a bending structure according to Example 2 of the present invention is applied, with Fig. 7(A) showing the extended state and Fig. 7(B) showing the bent state. Note that in Example 2, components corresponding to those in Example 1 are assigned the same reference numerals and redundant explanations will be omitted.

[0091] The close contact setting portion 21 of the second embodiment includes a receiving portion 33 provided on the other side of the drive wire 19, and a compression coil spring 35 as an elastic body interposed between the fixed receiving body 14 and the receiving portion 33. The receiving portion 33 is connected to the drive wire 19 by crimping.

[0092] The compression coil springs 35 are fitted to the plurality of drive wires 19. Each compression coil spring 35 applies tension to the plurality of drive wires 19 relative to the movable part 13 when the multiple flexible body 15 is in an extended state.

[0093] Therefore, tension can be applied to the plurality of drive wires 19 by setting the load of the compression coil spring 35, and the inner and outer coil springs 25, 23 can be set in a tightly contacted state.

[0094] The compression coil spring 35 as an elastic body can be made of metal, resin, or the like, and can have an appropriate shape depending on the elastic coefficient, etc. When the elastic body is made of rubber, it may be in the shape of a column, a tube, or the like.

[0095] The compression coil spring 35 is configured to be arranged in parallel to the drive wire 19 so as to exert an elastic force in the axial direction. "Parallel" here means that the compression coil spring 35 is arranged so that the axial direction and the direction in which the elastic force acts are parallel. However, strict parallelism in both directions is not necessary, and a case in which one of the directions is slightly inclined relative to the other is also included in the "parallel" category.

[0096] The axial dimension of each compression coil spring 35 in a free state is set to be larger than the axial dimension between the receiving portion 33 and the mounting base 11. Therefore, each compression coil spring 35 is compressed in accordance with the dimensional difference between the receiving portion 33 and the mounting base 11. Due to this compression, a load is applied to each compression coil spring 35, and tension corresponding to the load is applied to the drive wire 19.

[0097] Therefore, in the second embodiment as well, the tight contact state between the inner and outer coil springs 25, 23 can be established by setting the load of the compression coil spring 35, and the same effects as those in the first embodiment can be obtained.

[0098] The operating force for compressing the compression coil spring 35 coaxial with the outer wire 19 can be assisted by the elastic force of the expanding compression coil spring 35 coaxial with the inner wire 19. This prevents an increase in the overall operating force required to bend the bending structure 1, making it easier to bend the bending structure 1. [Example]

[0099] 8 is a conceptual diagram showing a manipulator to which a bending structure according to Example 3 of the present invention is applied. In Example 3, the same reference numerals are used to designate components corresponding to those in Example 2, and redundant explanations will be omitted.

[0100] The close contact setting portion 21 of the present embodiment 3 uses a single elastic compression coil spring 21 for the pair of drive wires 19 of the bending structure 1. Specifically, a support member 37 is provided that spans between the receiving portions 33 of the pair of drive wires 19, and the elastic body 21 is interposed between the support member 37 and the fixed receiving body 14. The rest is the same as in the embodiment 2.

[0101] The support member 37 is a plate-like body provided between the receiving portions 33 of the paired drive wires 19. The drive wires 19 are inserted through the support member 37. The support member 37 is pressed against the receiving portions 33 by a compression coil spring 21. The support member 37 can also be formed integrally with the receiving portions 33.

[0102] In the third embodiment, the same effects as those in the second embodiment can be achieved. [Example]

[0103] 9 is a conceptual diagram showing a manipulator to which a bending structure according to Example 4 of the present invention is applied. In Example 4, the same reference numerals are used to designate components corresponding to those in Example 1, and redundant explanations will be omitted.

[0104] In the fourth embodiment, the elastic body is a tension coil spring 21, which is provided between the support portion 39 of the shaft 5 and the receiving portion 33 of the drive wire 19. Specifically, the shaft 5 has support portions 39 that are positioned opposite each other in the axial direction, sandwiching the receiving portion 33 of each drive wire 19. Since the fixed receiver 14 is fixed to the shaft 5, the support portions 39 are also provided on the fixed receiver 14. The tension coil spring 21 is interposed between the support portions 39 and the receiving portion 33.

[0105] In the fourth embodiment, the pulley 29 is omitted, and the receiving portion 33 is connected to the operating mechanism.

[0106] Therefore, the tension of the drive wire 19 can be set by setting the load of the tension coil spring 21. This tension can set the inner and outer coil springs 25, 23 in a tightly packed state, and the same effects as those of the first embodiment can be obtained.

[0107] However, a pulley 29 may be provided as in the first embodiment. The rest is the same as the first embodiment.

[0108] The support portion 39 can be provided at the end of the shaft 5 or inside the shaft 5. The shape of the support portion 39 may be any shape that can support the tension coil spring 21. [Explanation of symbols]

[0109] 1 Bent structure 5 shaft 11 Mounting base 13 Movable part (one side receiving member) 14 Fixed receiver (other side receiver member) 15 Multiple flexible bodies 16 Double coil spring 17 Flexible tube 19 Drive wire (cord-like member) 21 Close Setting Section 22 Control section 23 Outer coil spring 25 Inner coil spring

Claims

1. A bending structure in which multiple flexible bodies can bend from an extended state to a bent state, an outer coil spring constituting the multiple flexible body; an inner coil spring arranged inside the outer coil spring, with wires overlapping between the wires of the outer coil spring in a coil radial direction to form the multiple flexible body; a one-side receiving member for receiving one side of the multiple flexible bodies; an other-side receiving member that receives the other side of the multiple flexible bodies; a plurality of cord-like members, one side of which is fixed to the one-side support member and the other side of which is routed through the other-side support member, for manipulating the displacement of the multiple flexible bodies into a bent state; an operating unit provided on the other side of the cord-like member for operating the displacement of the multiple flexible bodies between the extended state and the bent state by performing a relative pulling and pulling back operation between the plurality of cord-like members; a close contact setting unit that pulls the plurality of cord-like members toward the other-side receiving member without operating the operating unit, adjusts the gap between the one-side receiving member and the other-side receiving member, and sets a close contact state between the wires of the inner coil spring and the outer coil spring in the stretched state of the multiple flexible body; A bending structure comprising:

2. 2. The bending structure of claim 1, In the close contact state, the frictional force between the wires is reduced relative to the restoring force of the multiple flexible bodies returning from the bent state to the extended state. bending structure.

3. 2. The bending structure of claim 1, The operating unit is supported so that its position can be adjusted in the direction of the extension state of the multiple flexible bodies; the close contact state is set by adjusting the position of the operation unit in the extended state of the multiple flexible bodies. bending structure.

4. The bending structure of claim 3, the operating portion includes a pulley that is supported on the other-side receiving member side and that is rotatably operable and movable to loop the cord-like member around the one-side receiving member, The close setting unit includes a tensioner that adjusts the position of the pulley. bending structure.

5. 2. The bending structure of claim 1, the close contact setting portion includes a receiving portion provided on the other side of the cord-like member, and an elastic body interposed between the other side receiving member and the receiving portion, and applying tension to the multiple cord-like members in a stretched state of the multiple flexible bodies relative to the one side receiving member, The close contact state is established by applying the tension by the elastic body. bending structure.

6. The bent structure according to any one of claims 1 to 5, a flexible tube having one end connected to the one side receiving member, containing the inner coil spring and the outer coil spring, and constituting the multiple flexible body together with the inner coil spring and the outer coil spring; an attachment base connected to the other end of the flexible tube and passing through the inner coil spring and the outer coil spring together with the flexible tube; Equipped with The other-side receiving member is fixed within the end of the hollow shaft, the close contact setting portion connects the mounting base to an end of the hollow shaft and moves it, and the other-side receiving member receives the other ends of the inner coil spring and the outer coil spring, thereby setting the close contact state. bending structure.

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