buckling structure

Abstract

To provide a bending structure which can achieve decrease of an outer diameter or increase of an inner diameter of a second member which covers an outer periphery of a first member.SOLUTION: A bending structure includes: a first member 11 which may bend and extend; a second member 13 which covers an outer periphery of the first member 11 and may bend and extend with the first member 11; recessed parts 23 provided at an inner periphery of the second member 13; and wires 9 each of which is held between the first member 11 and the second member 13 while at least partially entering the recessed part 23 in a radial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a bending structure that realizes a joint function of a robot or the like. [Background technology]

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

[0003] The bending structure of Patent Document 1 includes an elastic member as a first member and a flexible member as a second member that covers the outer periphery of the elastic member. This bending structure bends in response to the tension of the drive wire.

[0004] The drive wire is guided by passing through insertion holes provided in the multiple wave washers that make up the flexible member, and its displacement in the circumferential direction is restricted, thereby preventing malfunction of the bending structure.

[0005] However, in this configuration, it is necessary to ensure a certain radial width inside and outside the insertion hole of the wave washer, which means that in conventional bending structures, there are limitations to reducing the outer diameter or increasing the inner diameter of the flexible member.

[0006] This problem is not limited to bending structures having flexible members made of wave washers, but occurs widely in bending structures that guide cord-like members such as drive wires through insertion holes or the like. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-172001 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved was that there was a limit to how small the outer diameter or how large the inner diameter of the second member that covers the outer periphery of the first member could be. [Means for solving the problem]

[0009] The present invention provides A bending structure that realizes a bending / extending joint function of a manipulator, etc., Provided is a bending structure comprising: a first member capable of bending and extending; a second member covering the outer periphery of the first member and capable of bending and extending together with the first member; a recess provided radially in at least one of the first member and the second member; and a cord-like member held between the first member and the second member with at least a portion of the cord-like member inserted radially into the recess, and manipulated for the bending and extending. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce the outer diameter and increase the inner diameter of the second member that covers the outer periphery of the first member. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a front view showing a bending structure according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view partially showing a bent portion of the bent structure of FIG. [Figure 3] FIG. 3 is a plan view showing a bending portion of the bending structure of FIG. [Figure 4] FIG. 4 is a plan view showing a bending portion of a bending structure according to Example 2 of the present invention. [Figure 5] FIG. 5 is a plan view showing a bending portion of a bending structure according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The objective of reducing the outer diameter and increasing the inner diameter of the second member that covers the outer periphery of the first member is achieved by providing a recess in at least one of the first member and the second member into which at least a portion of the cord-like member can be inserted.

[0013] That is, the bending structure (1) includes a first member (11), a second member (13), a recess (23), and a cord-like member (9). The first member (11) is capable of bending and extending. The second member (13) covers the outer periphery of the first member (11) and is capable of bending and extending together with the first member (11). The recess (23) is provided in the radial direction in at least one of the first member (11) and the second member (13). The cord-like member (9) is held between the first member (11) and the second member (13) with at least a portion of the cord-like member (9) fitted into the recess (23) in the radial direction.

[0014] At least one of the first member (11) and the second member (13) may be formed in a cylindrical shape, and the recess (23) may be a groove provided in at least one of the first member (11) and the second member (13) formed in a cylindrical shape.

[0015] When the recesses (23) are formed as grooves, the second member (13) may be cylindrical with a plurality of wave washers (19) joined together in the axial direction, and the recesses (23) may be provided in each of the wave washers (19) that are continuous in the axial direction.

[0016] The recess 23 may accommodate and hold a plurality of cord-like members 9. In this case, the cord-like members 9 in the recess 23 may be arranged along the circumferential direction according to the shape of the recess 23. [Example]

[0017] [Bending structure] FIG. 1 is a front view showing a bending structure according to Example 1 of the present invention, FIG. 2 is a cross-sectional view showing a part of a bending portion of the bending structure, and FIG. 3 is a plan view showing the bending portion of the bending structure.

[0018] The bending structure 1 is applied to a joint function part of various medical and industrial equipment such as a manipulator, a robot, and an actuator. The joint function part is an apparatus, mechanism, device, etc. that functions as a flexing / extending joint.

[0019] Flexion and extension refer to flexion and extension in the axial direction. The axial direction is the direction along the axis of the bending structure 1, but it does not need to be interpreted strictly and also includes a direction slightly inclined relative to the axis of the bending structure 1.

[0020] The bending structure 1 includes a base portion 3, a movable portion 5, a bending portion 7, and a wire 9 as a cord-like member.

[0021] The base 3 and the movable part 5 are each a columnar body, for example, a cylindrical body, made of an appropriate material such as metal, resin, etc. Note that the base 3 and the movable part 5 are not limited to columnar bodies and may have an appropriate shape depending on the device to which the bending structure 1 is applied, etc.

[0022] The movable portion 5 is supported by the base portion 3 through a bending portion 7 and is movable in the axial direction.

[0023] The bending portion 7 includes a first member 11 and a second member 13 .

[0024] The first member 11 is a member that can be bent and extended. The first member 11 functions as a core material and suppresses compression of the bending portion 7 in the axial direction.

[0025] The first member 11 of this embodiment has a cylindrical double coil structure and is made up of an inner coil portion 15 and an outer coil portion 17. This first member 11 is capable of elastically bending and extending, and is also capable of withstanding axial compression.

[0026] The first member 11 can be, for example, a single tightly coiled coil, a resin cylindrical body, or any other flexible cylindrical body that can withstand axial compression. The first member 11 does not need to have elasticity as long as it has the flexibility to bend and stretch.

[0027] Furthermore, the first member 11 may be a member that can be compressed in the axial direction, such as a compression coil spring, as long as it can suppress compression between the base portion 3 and the movable portion 5 to some extent.

[0028] In this embodiment, the inner and outer coil portions 15 and 17 are each a coil spring having elasticity that allows bending in the axial direction. The material of the inner and outer coil portions 15 and 17 may be an appropriate material such as metal or resin depending on the device to which the bending structure 1 is applied. The cross-sectional shape of the wire of the inner and outer coil portions 15 and 17 is circular with the same wire diameter, but it can also be semicircular, elliptical, or the like. The cross-sectional shapes and wire diameters of the inner and outer coil portions 15 and 17 may be different from each other.

[0029] The inner coil portion 15 has a smaller central diameter than the outer coil portion 17, and is threaded into the outer coil portion 17. As a result, the winding portions 15a of the inner coil portion 15 fit between the adjacent winding portions 17a of the outer coil portion 17. This fit is maintained not only when the first member 11 is straight but also when it is bent, making it possible to suppress axial compression of the bent portion 7.

[0030] The central diameter of the inner and outer coil portions 15 and 17 is constant from one end to the other in the axial direction, but it can also be changed in the axial direction.

[0031] When the first member 11 having such a double coil structure is bent, the gap between adjacent windings 17a of the outer coil portion 17 becomes smaller on the inside of the bend, and the gap between adjacent windings 17b of the outer coil portion 17 becomes larger on the outside of the bend.

[0032] As a result, the length of the first member 11 at the axial center when the outer coil portion 17 is bent does not change compared to when it is straight. Therefore, when the first member 11 is used to guide a flexible member such as a push-pull cable on its inner peripheral side so that the flexible member can move in the axial direction, the path length of the flexible member can be kept constant.

[0033] The second member 13 covers the outer periphery of the first member 11 and is a member that can bend and extend together with the first member 11. In this embodiment, the second member 13 is configured to have a cylindrical shape as a whole by stacking a plurality of wave washers 19 in the axial direction. The second member 13 is bendable due to the elastic deformation of the wave washers 19.

[0034] The second member 13 can be configured with a double coil structure, a bellows, or other cylindrical body, etc. The second member 13 may also be a compression coil spring, etc.

[0035] Each wave washer 19 is formed in an annular shape. Between axially adjacent wave washers 19, the peaks 19a of one wave washer 19 abut against the valleys 19b of the other wave washer 19. These abutting peaks 19a and valleys 19b are joined by an appropriate means such as welding or adhesive.

[0036] A plurality of flat washers 21, which have a smaller deformation amount than the wave washer 19, are attached to both axial ends of the second member 13. The base part 3 and the movable part 5 are connected to both ends of the second member 13 via these flat washers 21. This connection is performed by an appropriate means such as welding. The flat washers 21 may be omitted.

[0037] The second member 13 has a plurality of recesses 23 formed in the radial direction, each of which guides the wire 9. The radial direction refers to a direction along the diameter of the bending structure 1, but also includes a direction slightly inclined relative to the diameter of the bending structure 1.

[0038] The multiple recesses 23 are arranged at equal circumferential intervals on the inner circumference of the second member 13. In this embodiment, the recesses 23 are provided every 90 degrees in the circumferential direction. However, the number of recesses 23 can be changed, such as every 60 degrees, 120 degrees, or 180 degrees in the circumferential direction. Furthermore, the intervals between the multiple recesses 23 do not have to be equal and may vary. The circumferential direction refers to the direction along the outer periphery of the bending structure 1.

[0039] These recesses 23 are provided in each of the axially consecutive wave washers 19. Therefore, the recesses 23 thin the wave washers 19 in the radial direction, and reduce the rigidity of the wave washers 19 and the second member 13.

[0040] In this embodiment, recesses 23 are provided in all of the wave washers 19 and flat washers 21 that are continuous in the axial direction. However, recesses 23 may be provided in only some of the wave washers 19. Therefore, recesses 23 can be provided in part or the entire axial direction of the second member 13. When recesses 23 are provided in part of the axial direction of the second member 13, the inner diameter of the wave washers that do not have recesses 23 can be made larger than the inner diameter of the wave washers 19 that have recesses 23.

[0041] The corresponding recesses 23 between the wave washers 19 communicate with each other in the axial direction, and as a whole form a recessed line along the axial direction provided on the inner periphery of the cylindrical second member 13.

[0042] However, the corresponding recesses 23 between the wave washers 19 may be offset in the circumferential direction to form a spiral recess as a whole.

[0043] Each recess 23 opens at the inner periphery of the wave washer 19 of the second member 13 and faces between the first member 11 and the second member 13. In a plan view, the recess 23 of this embodiment is composed of a straight portion 23a on the inner periphery along the radial direction and a semicircular portion 23b on the outer periphery that is continuous with the straight portion 23a.

[0044] It is sufficient that at least a portion of the recess 23 is concave in the radial direction, and the entire recess 23 does not need to be concave in the radial direction. Therefore, the entire recess 23 may be provided in a direction inclined relative to the radial direction.

[0045] Furthermore, since the recess 23 only needs to be provided in at least one of the first member 11 and the second member 13, it is possible to provide it not only on the inner circumference of the second member 13, but also on the outer circumference of the first member 11 or on both the outer circumference of the first member 11 and the inner circumference of the second member 13.

[0046] When recesses are provided on both the outer periphery of the first member 11 and the inner periphery of the second member 13, the recesses of the first member 11 and the second member 13 may face each other radially to form a single recess, or the recesses of the first member 11 and the second member 13 may be offset circumferentially to form a single recess.

[0047] The tip of the wire 9 is attached to the movable part 5, passes through the bending part 7, and has its base connected to an operating mechanism or the like (not shown). When the wire 9 is pulled in the axial direction, the movable part 5 is driven to bend the bending structure 1.

[0048] In this embodiment, a plurality of wires 9 are provided, and by pulling one or more of them, it is possible to bend the bending portion 1 in all directions of 360° in a plan view. The number of wires 9 for driving the movable portion 5 can be set appropriately depending on the bending operation required of the bending structure 1.

[0049] The wire 9 is guided by the recess 23 at the bent portion 7, and its displacement in the circumferential direction is restricted. That is, the wire 9 is held between the first member 11 and the second member 13 with at least a portion of the wire 9 fitted into the recess 23 in the radial direction.

[0050] By guiding the wire 9 in this way using the recess 23 facing between the first member 11 and the second member 13, it is possible to increase the inner diameter while keeping the outer diameter of the second member 13 the same, or to decrease the outer diameter while keeping the inner diameter of the second member 13 the same, compared to the case of conventional insertion holes.

[0051] The wire 9 in this embodiment has a circular cross-sectional shape, and the entire circle is fitted into the recess 23. The radial gap S between the first member 11 and the second member 13 is formed to be smaller than the diameter of the wire 9, and circumferential displacement of the wire 9 fitted into the recess 23 is suppressed.

[0052] It is sufficient that the wire 9 is pushed into the recess 23 at least a little in the radial direction so as to suppress displacement in the circumferential direction. Therefore, the recess 23 may have an appropriate shape according to the amount of insertion of the wire 9. Furthermore, as long as the recess 23 can suppress displacement in the circumferential direction, the cross-sectional shape of the wire 9 may be elliptical, rectangular, or the like.

[0053] The wire 9 preferably has flexibility to the extent that it does not hinder the bending and extension of the bending structure 1. The wire 9 can also be made of metal with an insulating coating to form a current path. The cord-like member is not limited to the wire 9, and can be a twisted wire, a solid wire, a piano wire, an articulated rod, a chain, a string, a thread, a rope, or the like.

[0054] [Operation etc.] In the bending structure 1 of this embodiment, an operator can pull any one or more wires 9 to direct the movable part 5 in a desired direction.

[0055] At this time, the wire 9 is held between the first member 11 and the second member 13 with a portion of the wire 9 inserted into the recess 23, so that circumferential displacement is restricted. As a result, the wire 9 is pulled at an appropriate position, which prevents malfunction of the bending structure 1 and stabilizes its operation.

[0056] When the wire 9 is pulled and the bending structure 1 is bent, the length of the center of the first member 11 does not change, so the path length of the member passing through the inside and the operation of the bending structure 1 become more stable.

[0057] Furthermore, before and after bending, the corresponding winding portions 15a of the inner coil portion 15 continue to fit between adjacent winding portions 17a of the outer coil portion 17 of the first member 11, thereby suppressing axial compression of the bending structure 1 and making the path length of the member passing through the interior and the operation of the bending structure 1 more stable.

[0058] The second member 13 bends together with the first member 11 due to the elastic deformation of the wave washers 19. At this time, the rigidity of each wave washer 19 of the second member 13 is reduced by the recesses 23, so that the bending structure can be bent with a smaller force.

[0059] [Effects of Example 1] As described above, the bending structure 1 of this embodiment comprises a first member 11 that can bend and extend, a second member 13 that covers the outer periphery of the first member 11 and can bend and extend together with the first member 11, a recess 23 provided on the inner periphery of the second member 13, and a wire 9 held between the first member 11 and the second member 13 with at least a portion of the wire 9 radially inserted into the recess 23.

[0060] Therefore, in the bending structure 1, the wire 9 is guided by the recess 23, thereby stabilizing operation. Moreover, in the bending structure 1, the outer diameter of the second member 13 that covers the outer periphery of the first member 11 can be made smaller and the inner diameter can be made larger, compared to when the wire 9 is guided by a conventional insertion hole.

[0061] Furthermore, in the bending structure 1, the recess 23 can reduce the rigidity of the second member 13, and the bending structure can be bent with a smaller force.

[0062] The recess 23 is a groove provided on the inner periphery of the second member 13 formed in a cylindrical shape, and therefore the wire 9 can be guided reliably.

[0063] The second member 13 is cylindrical and has a plurality of wave washers 19 stacked in the axial direction, and the recesses 23 are provided in the wave washers 19 that are continuous in the axial direction.

[0064] Therefore, in this embodiment, the recess 23 can be easily formed in the wave washer 19 by pressing or the like, and by stacking wave washers 19 having the recess 23, the groove-shaped recess 23 can be easily formed at the desired position in the axial direction of the second member 13. [Example]

[0065] 4 is a plan view showing a bending structure according to Example 2 of the present invention. In Example 2, the same reference numerals are used to designate components corresponding to those in Example 1, and redundant explanations will be omitted.

[0066] In this embodiment, the recesses 23 are provided in the first member 11. Therefore, the second member is formed by laminating annular wave washers 19 that do not have the recesses 23. The rest is the same as in the first embodiment.

[0067] The first member 11 is a cylindrical flexible member and has a plurality of recesses 23 on its outer periphery. The recesses 23 are set according to the cross-sectional shape of the first member 11. In this embodiment, the recesses 23 are formed by the concave curved surface of the first member 11. Adjacent to the recesses 23, the first member 11 is provided with a protrusion 25 made of a convex curved surface. A gap S smaller than the diameter of the wire 9 is formed between the protrusion 25 and the inner periphery of the second member 13.

[0068] In Example 2, the same effects as those of Example 1 can be achieved. In addition, in the example, since the recess 23 is provided in the first member 11, the radial width of the second member 13 can be freely set, and the outer diameter of the second member 13 can be reduced or the inner diameter can be increased. [Example]

[0069] 5 is a plan view showing a bending structure according to Example 3 of the present invention. In Example 3, the same reference numerals are used to designate components corresponding to those in Example 1, and redundant explanations will be omitted.

[0070] In this embodiment, a recess 23 is provided in the second member 13, and a plurality of wires 9 are housed and held in this recess 23. The rest is the same as in the first embodiment.

[0071] Each recess 23 has a fan-shaped recess, and the wires 9 are arranged along the circumferential direction according to the shape of the recess 23.

[0072] The recess 23 in this embodiment accommodates two wires 9 arranged along the circumferential direction, and is designed to fit a portion of these wires 9 in the radial direction, approximately half of the radial direction in this embodiment.

[0073] The plurality of wires 9 in each recess 23 are a combination of a plurality of operation wires for operating the movable portion 5, or a combination of the operation wires 9 and their guide wires or current path wires.

[0074] In the third embodiment, the recess 23 is larger than in the first embodiment, and the function of the bending structure 1 can be improved by the plurality of wires 9. In addition, the third embodiment can also achieve the same effects as the first embodiment. [Explanation of symbols]

[0075] 1 Bent structure 9 Wire (cord-like member) 11 First member 13 Second member 19 Wave washer 23 Recess

Claims

1. A bending structure that realizes a bending / extending joint function of a manipulator or the like, a first member capable of bending and extending; a second member that covers the outer periphery of the first member and is capable of bending and extending together with the first member; a recess provided radially in at least one of the first member and the second member; a cord-like member that is held between the first member and the second member in a state where at least a portion of the cord-like member is inserted into the recess in the radial direction and that is operated for the bending and extension; A bending structure comprising:

2. 2. The bending structure according to claim 1, At least one of the first member and the second member is formed in a cylindrical shape, The recess is a recess provided in at least one of the first member and the second member, which are formed in a cylindrical shape. bending structure.

3. The bent structure according to claim 1 or 2, the second member is a cylindrical member in which a plurality of wave washers are stacked in the axial direction, The recess is provided in a wave washer that is continuous in the axial direction. bending structure.

4. The bent structure according to any one of claims 1 to 3, The recess accommodates and holds a plurality of cord-like members. bending structure.

5. 5. The bending structure according to claim 4, The plurality of cord-like members in the recess are arranged along a circumferential direction according to the shape of the recess. bending structure.

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