Bending structure

Abstract

The objective of this invention is to provide a curved structure that simplifies the structure. The curved structure of this invention includes: an inner cylinder (3) including a first inner coil portion (15) and a first outer coil portion (13), wherein a corresponding coil portion (15a) of the first inner coil portion (15) is fitted into a gap (13b) between adjacent coil portions (13a) of the first outer coil portion (13); an outer cylinder (5) having a gap (21) covering at least a portion of the outer periphery of the inner cylinder (3), including a second inner coil portion (19) and a second outer coil portion (17), wherein a corresponding coil portion (19a) of the second inner coil portion (19) is fitted into a gap (17b) between adjacent coil portions (17a) of the second outer coil portion (17); and a drive line (9a) and a guide line (9b) that are inserted through the gap (21) between the inner cylinder (3) and the outer cylinder (5) in the axial direction and guided thereto.

Description

Technical Field

[0001] The present invention relates to a curved structure for a joint function part of a robot or manipulator. Background Technology

[0002] Robots, manipulators, or actuators may contain joint-like functional parts that are capable of bending and extending. For example, a bending structure, such as that described in Patent Document 1, may be used as such a joint-like functional part.

[0003] The bending structure in Patent Document 1 is constructed by engaging multiple disc elements in a manner that allows them to freely rock back and forth. The bending action of the entire structure is achieved by rocking each disc element.

[0004] A starting cable, acting as a rope-like component, is inserted into and guided into each disc element. The bending action of the bending structure is achieved by stretching the starting cable.

[0005] However, the existing curved structure is complex because it incorporates multiple disk elements and inserts starter cables into each disk element.

[0006] [Existing Technical Documents]

[0007] [Patent Literature]

[0008] Patent Document 1: Japanese Patent Publication No. 2009-538186 Summary of the Invention

[0009] [The problem the invention aims to solve]

[0010] The problem to be solved lies in the complexity of the curved structure.

[0011] [Technical means to solve the problem]

[0012] The most important feature of the curved structure of the present invention is that it includes: an inner cylinder comprising a first inner coil portion and a first outer coil portion, wherein a corresponding coil portion of the first inner coil portion is fitted into a gap between adjacent coil portions of the first outer coil portion; an outer cylinder having a gapped covering at least a portion of the outer periphery of the inner cylinder, comprising a second inner coil portion and a second outer coil portion, wherein a corresponding coil portion of the second inner coil portion is fitted into a gap between adjacent coil portions of the second outer coil portion; and a plurality of cord-like members in the circumferential direction, which are inserted into the gap between the inner cylinder and the outer cylinder and guided along the axial direction.

[0013] [The effects of the invention]

[0014] According to the present invention, a bending structure capable of bending and recovering can be simply realized by arranging a cable-like member used in operations and other processes in the gap between the inner and outer cylinders, including the inner and outer coil sections. Furthermore, compression of the inner and outer cylinders can be prevented before and after bending, thereby stabilizing the posture, and the cable-like member can be reliably guided through the gap between the inner and outer cylinders. Attached Figure Description

[0015] Figure 1 This is a perspective view of the curved structure of Embodiment 1 of the present invention.

[0016] Figure 2 Therefore Figure 1 A three-dimensional cross-sectional view of a portion of a curved structure.

[0017] Figure 3 yes Figure 1 The plan view of the end members of the curved structure is omitted.

[0018] Figure 4 It means Figure 1 Cross-sectional views of the inner and outer cylinders of the curved structure.

[0019] Figure 5 It is a cross-sectional view showing the movement of the inner cylinder.

[0020] Figure 6 This is a plan view of the curved structure of Embodiment 2 of the present invention, omitting the end members.

[0021] [Explanation of Symbols]

[0022] 1: Bending structure

[0023] 3: Inner cylinder

[0024] 5: Outer cylinder

[0025] 7a, 7b: End components

[0026] 9a: Drive wire (cable-like component)

[0027] 9b: Guide line (cable-like component)

[0028] 11: Flexible tube (flexible component)

[0029] 13: First outer coil section

[0030] 13a: Volume

[0031] 15: First inner coil section

[0032] 15a: Volume

[0033] 17: Second outer coil section

[0034] 17a: Volume

[0035] 19: Second inner coil section

[0036] 19a: Volume

[0037] 21: Gap

[0038] 23: First through hole

[0039] 25: Second insertion hole Detailed Implementation

[0040] The structure of the curved structure is simplified by placing a cable-like member in the gap between the inner and outer cylinders, including the inner and outer coil sections.

[0041] That is, the curved structure (1) includes an inner cylinder (3), an outer cylinder (5), and cable-like members (9a, 9b). The inner cylinder (3) includes a first inner coil portion (15) and a first outer coil portion (13), with a corresponding coil portion (15a) of the first inner coil portion (15) fitting into a gap (13b) between adjacent coil portions (13a) of the first outer coil portion (13). The outer cylinder (5) covers at least a portion of the outer periphery of the inner cylinder (3) with a gap (21), including a second inner coil portion (19) and a second outer coil portion (17), with a corresponding coil portion (19a) of the second inner coil portion (19) fitting into a gap (17b) between adjacent coil portions (17a) of the second outer coil portion (17). The cable-like members (9a, 9b) are inserted through the gap (21) between the inner cylinder (3) and the outer cylinder (5) along the axial direction and are guided.

[0042] The curved structure (1) may include end members (7a, 7b) installed at both ends of either or both of the outer cylinder (5) and the inner cylinder (3), with the cable-like members (9a, 9b) inserted into the first through hole (23).

[0043] Alternatively, the curved structure (1) may include a flexible member (11) inserted into a first inner coil portion (15) of the inner cylinder (3), and the end members (7a, 7b) include a second insertion hole (25) through which the flexible member (11) is inserted.

[0044] The cable-like members (9a, 9b) may include: a driving cable-like member (9a) for driving the other end member (7b) relative to one of the end members (7a); and a guiding cable-like member (9b) disposed on both sides of the driving cable-like member (9a) in the circumferential direction to define the path of the driving cable-like member (9a).

[0045] Either or both of the drive cable member (9a) and the guide cable member (9b) can be set as the power path.

[0046] Alternatively, in the curved structure (1), the first inner and outer coil portions (15, 13) of the inner cylinder (3) and the second inner and outer coil portions (19, 17) of the outer cylinder (5) can be wound in opposite directions.

[0047] [Example 1]

[0048] [Bent Structure]

[0049] Figure 1 This is a perspective view showing the curved structure of Embodiment 1 of the present invention. Figure 2 It represents a three-dimensional cross-sectional view with the same part as the cross section. Figure 3 It is a plan view of a curved structure with the end members omitted. Figure 4 It is a cross-sectional view showing the inner and outer cylinders of a curved structure.

[0050] The bending structure 1 of this embodiment is applied to the joint function parts of various machines such as manipulators, robots, and actuators for medical or industrial use. It can cause relative displacement of the machine side components connected to both sides through bending and stretching movements.

[0051] The curved structure 1 includes an inner cylinder 3, an outer cylinder 5, end members 7a and 7b, a driving line 9a and a guiding line 9b as cable-like members, and a flexible tube 11 as a flexible member.

[0052] The inner cylinder 3 is a double coil that can be elastically bent and restored relative to the axial direction, including a first outer coil portion 13 and a first inner coil portion 15.

[0053] The first outer coil portion 13 and the first inner coil portion 15 each include a resilient coil spring. The material of both the first outer coil portion 13 and the first inner coil portion 15 can be metal or resin, etc. Furthermore, the cross-sectional shape of the bare wire in the first outer coil portion 13 and the first inner coil portion 15 is circular. However, the cross-sectional shape is not limited to a circle; it can also be semi-circular or elliptical, etc. Additionally, the cross-sectional shape, wire diameter, material, etc., of the first outer coil portion 13 and the first inner coil portion 15 can differ from each other.

[0054] The first inner coil portion 15 has a smaller center diameter than the first outer coil portion 13 and is screwed into the first outer coil portion 13. Furthermore, the center diameters of the first outer coil portion 13 and the first inner coil portion 15 are fixed from one end to the other in the axial direction. However, the center diameter of the first outer coil portion 13 can also vary in the axial direction.

[0055] The first outer coil portion 13 includes a plurality of gaps 13b, which are multiple gaps that separate adjacent coil portions 13a in the axial direction. The corresponding coil portion 15a of the first inner coil portion 15 is fitted into the plurality of gaps 13b from the inside. Through this fitting, the coil portion 15a of the first inner coil portion 15 comes into contact with both the coil portion 13a of the adjacent first outer coil portion 13.

[0056] On the other hand, the first inner coil portion 15 includes a spacing 15b, which is a plurality of gaps that separate adjacent coil portions 15a in the axial direction. The corresponding coil portion 13a of the first outer coil portion 13 is fitted into the plurality of spacings 15b from the outside. Through this fitting, the coil portion 13a of the first outer coil portion 13 comes into contact with both the coil portion 15a of the adjacent first inner coil portion 15.

[0057] Therefore, the axial compression of the inner cylinder 3 is restricted.

[0058] Like the inner cylinder 3, the outer cylinder 5 is a double coil that can be freely and elastically bent and recovered relative to the axial direction, including a second outer coil portion 17 and a second inner coil portion 19. The outer cylinder 5 covers the outer periphery of the inner cylinder 3 with a gap 21. Furthermore, when the outer cylinder 5 is shorter than the inner cylinder 3, it partially covers the inner cylinder 3 in the axial direction. Therefore, the outer cylinder 5 can be a structure that covers at least a portion of the outer periphery of the inner cylinder 3 with a gap 21.

[0059] The gap 21 is divided between the second inner coil portion 19 of the outer cylinder 5 and the first outer coil portion 13 of the inner cylinder 3 in the radial direction. The radial dimension of the gap 21 is set to be slightly larger than the diameter of the drive wire 9a and the guide wire 9b.

[0060] Therefore, the inner cylinder 3 and the outer cylinder 5 function as guides for the drive line 9a and the guide line 9b, respectively. Furthermore, the radial dimension of the gap 21 can be appropriately set within the range necessary to ensure its function as a guide for the drive line 9a and the guide line 9b.

[0061] The second outer coil portion 17 and the second inner coil portion 19 of the outer cylinder 5 are constructed in the same manner as the first outer coil portion 13 and the first inner coil portion 15 of the inner cylinder 3. However, the winding direction of the outer cylinder 5 can be set to either the same as or opposite to the winding direction of the inner cylinder 3.

[0062] When the winding directions of the inner cylinder 3 and the outer cylinder 5 are set to opposite (reverse winding), the inner cylinder 3 and the outer cylinder 5 can resist the reverse torsion respectively, thereby improving the overall torsional rigidity of the bending structure 1.

[0063] Similar to the first outer coil portion 13 and the first inner coil portion 15 of the inner cylinder 3, the second outer coil portion 17 and the second inner coil portion 19 include elastic coil springs, which may be formed of metal or resin. The cross-sectional shape of the bare wire in the second outer coil portion 17 and the second inner coil portion 19 is circular, but not limited to circular. In addition, the cross-sectional shape, material, wire diameter, etc. of the second inner coil portion 19 and the second outer coil portion 17 may be different from each other.

[0064] The second inner coil portion 19 has a smaller center diameter than the second outer coil portion 17 and is screwed into the second outer coil portion 17. The center diameters of the second outer coil portion 17 and the second inner coil portion 19 are fixed from one end to the other in the axial direction, but can also vary in the axial direction.

[0065] The second outer coil portion 17 includes a plurality of spacings 17b, which separate adjacent coil portions 17a in the axial direction. The corresponding coil portion 19a of the second inner coil portion 19 is fitted into the plurality of spacings 17b from the inside. Through this fitting, the coil portion 19a of the second inner coil portion 19 and the adjacent coil portion 17a of the second outer coil portion 17 come into contact.

[0066] On the other hand, the second inner coil portion 19 includes a plurality of gaps 19b, which are multiple gaps that separate adjacent coil portions 19a in the axial direction. The corresponding coil portion 17a of the second outer coil portion 17 is fitted into the plurality of gaps 19b from the outside. Through this fitting, the coil portion 17a of the second outer coil portion 17 comes into contact with both the coil portion 19a of the adjacent second inner coil portion 19.

[0067] As a result, the axial compression of the outer cylinder 5 is restricted.

[0068] End members 7a and 7b are cylindrical and contain metal or the like. Alternatively, end members 7a and 7b may also be other shapes such as prismatic. These end members 7a and 7b are installed at the axial ends of the outer cylinder 5 by appropriate fixing methods such as welding. Furthermore, end members 7a and 7b may also be installed at the axial ends of the inner cylinder 3 or at the axial ends of both the inner cylinder 3 and the outer cylinder 5.

[0069] The end members 7a and 7b can be installed on either the second inner coil portion 19 or the second outer coil portion 17 in the outer cylinder 5. In this embodiment, the end members 7a and 7b are installed on the second outer coil portion 17.

[0070] The first through hole 23 and the second through hole 25 are disposed through the end member 7a and the end member 7b along the axial direction. The first through hole 23 is connected in the axial direction to the gap 21 between the inner cylinder 3 and the outer cylinder 5, so as to allow the drive wire 9a and the guide wire 9b to be inserted.

[0071] The second insertion hole 25 is axially connected to the interior of the inner cylinder 3, allowing the flexible tube 11 to be inserted. In this embodiment, the second insertion hole 25 is located at the axial center of the end member 7a and the end member 7b, and is formed with a circular cross-section.

[0072] The end members 7a and 7b are respectively mounted on the machine-side members that are relatively displaced by the bending structure 1. For example, one end member 7a is mounted on the front end of the machine-side member, and the other end member 7b is mounted on the base end of the machine-side member. These end members 7a and 7b may also be omitted. In this case, both ends of the outer cylinder 5 can be directly mounted on the machine-side members.

[0073] The drive line 9a and guide line 9b are drive cable-like members and guide cable-like members containing metal or the like. The drive line 9a and guide line 9b have a degree of flexibility that does not hinder the bending and recovery of the bending structure 1.

[0074] The cross-sectional shape of the drive wire 9a and the guide wire 9b is set to be the same as the first insertion hole 23 as a circle. In addition, it can also be set to different shapes such as ellipse or rectangle. As long as the drive wire 9a and the guide wire 9b are cable-like components, they can be made of stranded wire, NiTi (nickel-titanium) single wire, piano wire, multi-joint rod, chain, belt, yarn, rope, etc.

[0075] Furthermore, the guide line 9b is not limited to metal or the like, but can also be formed of resin. Moreover, the guide line 9b does not have to be a cable-like component; it can also be a columnar or rod-like component.

[0076] The drive line 9a and guide line 9b are inserted through the gap 21 between the inner cylinder 3 and the outer cylinder 5 along the axial direction and are guided. In this embodiment, multiple drive lines 9a and guide lines 9b are provided at specific intervals in the circumferential direction. In addition, the drive line 9a is guided in a straight line along the axial direction, or it can be guided in a spiral shape around the axis.

[0077] The ends 27 of the drive cable 9a and the guide cable 9b are inserted through the first through holes 23 of the end members 7a and 7b and pulled out to the outside. The ends 27 pulled out from one end member 7a are prevented from detaching by end treatment.

[0078] The drive line 9a can drive the other end member 7b relative to one end member 7a. That is, the drive line 9a is directly or indirectly connected to the operating mechanism (not shown) and operated along the axial direction by bending the bending structure 1 by being pulled along the axial direction.

[0079] Furthermore, "operation along the axial direction" means moving the drive line 9a forward and backward in the axial direction. The number of drive lines 9a can be appropriately set according to the bending action of the bending structure 1.

[0080] Guide lines 9b are disposed on both sides of each drive line 9a in the circumferential direction, thereby limiting the path of the drive lines 9a. Guide lines 9b also limit the circumferential offset of the drive lines 9a. In this embodiment, by using guide lines 9b and drive lines 9a to mutually limit each other's circumferential offset, the path of the drive lines 9a is thus limited.

[0081] Furthermore, the guide wire 9b can also function as the drive wire 9a. Alternatively, the guide wire 9b can be omitted. Furthermore, one or both of the drive wire 9a and the guide wire 9b can be used as the power supply path. Additionally, the inner cylinder 3 can also be used as the power supply path.

[0082] The flexible tube 11 is a cylindrical component formed of resin or the like, inserted into the first inner coil portion 15 of the inner cylinder 3. The flexible tube 11 possesses flexibility sufficient to allow for bending and recovery of the bending structure 1. The end of the flexible tube 11 is inserted through the second insertion holes 25 of the end members 7a and 7b and pulled out to the outside. Alternatively, as a cable-like component, it may be possible to omit the drive and guide components and only provide a component for conducting electricity.

[0083] The flexible tube 11 is fitted into the second through hole 25 at its end. Thus, the inner cylinder 3 can be positioned relative to the end members 7a and 7b via the flexible tube 11. Furthermore, the positioning reference can be either the end member 7a or the end member 7b. The outer cylinder 5 is positioned by mounting it onto the end members 7a and 7b.

[0084] Therefore, in this embodiment, the inner cylinder 3 and the outer cylinder 5 are positioned using end members 7a and 7b, thereby accurately dividing the gap 21 for the insertion of the drive line 9a and the guide line 9b.

[0085] An air pipe or push-pull cable, or other driving component for driving an end effector, is inserted through the inside of the flexible tube 11. Alternatively, the flexible tube 11 may be omitted, and a driving component such as an air pipe or push-pull cable, or other flexible component, may be used as the flexible component. The flexible tube 11 or the flexible component itself may also be omitted.

[0086] [action]

[0087] Figure 5 This is a cross-sectional view of the inner cylinder 3 during bending. Furthermore, the bending of the outer cylinder 5 is the same as that of the inner cylinder 3, therefore refer to... Figure 5 Therefore, in Figure 5 In the middle, the symbol for the outer cylinder 5 is indicated by parentheses.

[0088] The curved structure 1 in this embodiment is as follows: Figure 4 As shown, when straight and unbent (extended), the corresponding roll 15a of the first inner coil portion 15 is fitted between the adjacent rolls 13a of the first outer coil portion 13 of the inner cylinder 3. The corresponding roll 19a of the second inner coil portion 19 of the outer cylinder 5 is also fitted between the adjacent rolls 17a of the second outer coil portion 17.

[0089] Therefore, in the bending structure 1, even if compressive force in the axial direction is applied, compression of the first inner coil portion 15 and the first outer coil portion 13 of the inner cylinder 3 and the second inner coil portion 19 and the second outer coil portion 17 of the outer cylinder 5 can be prevented, and overall compression can also be prevented. By preventing compression in the above manner, the length of the central portion remains unchanged, and the posture is stable.

[0090] Furthermore, when the inner cylinder 3 and the outer cylinder 5 are wound in opposite directions, the inner cylinder 3 and the outer cylinder 5 can resist the torsion in the opposite direction. Therefore, even if the force in the torsional direction is applied, the overall torsion is suppressed, and the posture is stable.

[0091] As described above, the bending structure 1 has high resistance to compression or torsion and stable posture, thus a stable gap 21 between the inner cylinder 3 and the outer cylinder 5 can be obtained, and the drive line 9a and the guide line 9b can be reliably guided through the gap 21.

[0092] The bending structure 1 is bent by the operator pulling out any one of the drive lines 9a. By pulling out different pairs of drive lines 9a in combination, it can be bent in all directions (360 degrees). Through this bending, the machine using the bending structure 1, such as the end effector of the operator, can be pointed in the desired direction.

[0093] After pulling out any of the drive cables 9a, as follows Figure 5 As shown, on the inner side of the bend, the distances 13b and 17b between adjacent coil portions 13a and 17a of the first outer coil portion 13 and the second outer coil portion 17 of the inner cylinder 3 and the outer cylinder 5 decrease, while on the outer side of the bend, the distances 13b and 17b between adjacent coil portions 13a and 17a of the first outer coil portion 13 and the second outer coil portion 17 of the inner cylinder 3 and the outer cylinder 5 increase. Therefore, the length of the center portion of the inner cylinder 3 remains unchanged during bending, resulting in a stable posture.

[0094] At this time, the first inner coil portion 15 and the second inner coil portion 19 of the inner cylinder 3 and the outer cylinder 5 are extruded outwards in a curved manner. The extrusion of the first inner coil portion 15 and the second inner coil portion 19 is permitted by the increased spacing 13b between the adjacent coil portions 13a and 17a of the first outer coil portion 13 and the second outer coil portion 17 of the inner cylinder 3 and the outer cylinder 5 on the curved outer side. Therefore, the bending operation can be performed smoothly.

[0095] Furthermore, during bending, the corresponding roll portions 15a and 19a of the first inner coil portion 15 and the second inner coil portion 19 are continuously fitted between the adjacent roll portions 13a and 17a of the first outer coil portion 13 and the second outer coil portion 17 of the inner cylinder 3 and the outer cylinder 5.

[0096] Therefore, similar to the straight form, axial compression of the curved structure 1 is suppressed, and in this respect, variation in the length of the central portion is also suppressed, resulting in a stable posture. Thus, a stable gap 21 between the inner cylinder 3 and the outer cylinder 5 can be obtained, and the drive line 9a and guide line 9b can be reliably guided through the gap 21.

[0097] In addition, when the second inner coil portion 19 of the outer cylinder 5 is extruded, the gap 21 between the inner cylinder 3 and the outer cylinder 5 becomes smaller on the inner side of the bend, and the gap 21 between the inner cylinder 3 and the outer cylinder 5 becomes larger on the outer side of the bend.

[0098] After bending, both the inner cylinder 3 and the outer cylinder 5 reliably return to their straight, uncompressed state before bending, where the first inner coil portion 15 and the second inner coil portion 19 are fitted between the adjacent coil portions 13a and 17a of the first outer coil portion 13 and the second outer coil portion 17. Therefore, the drive wire 9a and the guide wire 9b can be reliably guided through the gap 21 between the inner cylinder 3 and the outer cylinder 5 in the same manner as before bending.

[0099] [Effect of Example 1]

[0100] As described above, this embodiment includes: an inner cylinder 3, comprising a first inner coil portion 15 and a first outer coil portion 13, wherein the corresponding roll portion 15a of the first inner coil portion 15 is fitted into the gap 13b between adjacent roll portions 13a of the first outer coil portion 13; an outer cylinder 5, having a gap 21 covering the outer periphery of the inner cylinder 3, comprising a second inner coil portion 19 and a second outer coil portion 17, wherein the corresponding roll portion 19a of the second inner coil portion 19 is fitted into the gap 17b between adjacent roll portions 17a of the second outer coil portion 17; and a plurality of drive lines 9a and guide lines 9b in the circumferential direction, which are inserted through the gap 21 between the inner cylinder 3 and the outer cylinder 5 in the axial direction and guided thereto.

[0101] Therefore, in this embodiment, by simply placing the drive wire 9a and the guide wire 9b in the gap 21 between the inner cylinder 3 and the outer cylinder 5, which includes the outer coil section 13, the inner coil section 15, the outer coil section 17, and the inner coil section 19, a simple structure can be achieved that allows the bent structure 1 to be bent and restored by the operation of the drive wire 9a.

[0102] Furthermore, in the bending structure 1 of this embodiment, compression of the inner cylinder 3 and the outer cylinder 5 can be prevented before and after bending. Therefore, the drive line 9a and the guide line 9b can be reliably guided through the gap 21 between the inner cylinder 3 and the outer cylinder 5, thereby stabilizing the operation based on the drive line 9a.

[0103] In addition, the curved structure 1 of this embodiment is installed at both ends of the outer cylinder 5, including end members 7a and end members 7b through which the drive line 9a and the guide line 9b are respectively inserted into the first insertion hole 23.

[0104] Therefore, the bending structure 1 can position the drive line 9a and the guide line 9b at both ends, and can guide the drive line 9a and the guide line 9b more reliably.

[0105] In addition, the bending structure 1 of this embodiment includes a flexible tube 11 inserted into the first inner coil portion 15 of the inner cylinder 3, and the end members 7a and 7b include a second insertion hole 25 for inserting the flexible tube 11 into the axial portion.

[0106] Therefore, in this embodiment, it can be used as a path for inserting the flexible tube 11 into the first inner coil portion 15 of the inner cylinder 3. Furthermore, by positioning the inner cylinder 3 to the end members 7a and 7b via the flexible tube 11, and by positioning the outer cylinder 5 to the end members 7a and 7b through installation, the bending action can be smoothly performed by reliably positioning the inner cylinder 3 and the outer cylinder 5. Moreover, the gap 21 between the inner cylinder 3 and the outer cylinder 5 can be accurately defined, and the drive line 9a and the guide line 9b can be guided more reliably.

[0107] In addition, in this embodiment, when the first inner coil portion 15 and the first outer coil portion 13 of the inner cylinder 3 and the second inner coil portion 19 and the second outer coil portion 17 of the outer cylinder 5 are wound in opposite directions, the inner cylinder 3 and the outer cylinder 5 can resist torsion in different directions, thereby improving the overall torsional rigidity.

[0108] [Example 2]

[0109] Figure 6 This is a plan view of the curved structure of Embodiment 2 of the present invention, omitting the end members. Furthermore, in Embodiment 2, the same symbols used for the structures corresponding to Embodiment 1 are omitted, and repeated descriptions are omitted.

[0110] In Example 2, the centers of the inner cylinder 3 and the outer cylinder 5 are offset. Otherwise, it is the same as in Example 1.

[0111] In this embodiment, the centers O and O' of the inner cylinder 3 and the outer cylinder 5 are staggered, with the gap 21 in one of the staggered directions being narrower than the other. The gap 21 in one of the staggered directions is so narrow that the drive line 9a cannot be configured. Furthermore, the drive line 9a is configured only in the gap 21 on the other side of the staggered direction.

[0112] Therefore, in Embodiment 2, miniaturization (smaller diameter) can be achieved by omitting the drive line 9a. Otherwise, Embodiment 2 can also achieve the same effect as Embodiment 1.

Claims

1. A curved structure, comprising: The inner cylinder includes a first inner coil portion and a first outer coil portion, wherein the corresponding coil portion of the first inner coil portion is fitted into the gap between adjacent coil portions of the first outer coil portion; The outer cylinder has a gap covering at least a portion of the outer periphery of the inner cylinder, including a second inner coil portion and a second outer coil portion, wherein a corresponding roll portion of the second inner coil portion is fitted into the gap between adjacent roll portions of the second outer coil portion; A cable-like member is inserted along the axial direction through the gap between the inner cylinder and the outer cylinder and is guided therethrough. A flexible component is inserted into the first inner coil portion of the inner cylinder; and The end member includes a first through hole for inserting the cable-like member and a second through hole for inserting the flexible member. The end member is installed at both ends of either or both of the outer cylinder and the inner cylinder. The flexible member is fitted into the second through hole at its end, thereby positioning the inner cylinder relative to the end member via the flexible member.

2. The bending structure according to claim 1, wherein... The cord-like member includes: A drive cable-like member for driving the other end member relative to one end member; And a guide cable-like member is provided on both sides of the drive cable-like member in the circumferential direction to limit the path of the drive cable-like member.

3. The bending structure according to claim 2, wherein... Either or both of the drive cable member and the guide cable member are energized paths.

4. The bending structure according to claim 1, wherein... The first inner and outer coil sections of the inner cylinder and the second inner and outer coil sections of the outer cylinder are wound in opposite directions.

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