JP6677409B2 - Moving body - Google Patents

Description

  The present invention relates to a moving body using fluid pressure.

  Endoscopes for observing the inside of a body and catheters for administering a drug solution and discharging a body fluid are known as important medical devices. Since all of these instruments are used by being inserted into a thin tube in the body, the size in the radial direction is limited, and it is difficult to incorporate a complicated mechanism. For this reason, such devices do not have their own propulsion, and thus, in the past, medical practitioners had to apply force from the outside to push or pull them into the body.

  In recent years, active catheters and active endoscopes have been developed. For example, Patent Documents 1 to 3 disclose a tube self-propelled device using air pressure, an endoscope propulsion device, and a tube insertion device.

JP 2009-240713 A JP 2012-81130 A JP-A-5-293077

  The devices described in Patent Literatures 1 and 2 have a plurality of telescopic units or balloons in an axial direction, that is, a propulsion direction, and have a common point in that a propulsion force is generated by their deformation. However, in order to individually deform a plurality of telescopic units / balloons, it is necessary to independently control the air pressure for each telescopic unit / balloon, and thus a plurality of air tubes are required. This has been a barrier to miniaturization.

  A mobile body that can be propelled in a pipe is expected to be used not only in the body but also in a pipe such as a gas pipe or a complicated narrow terrain.

  The present invention has been made in such a situation, and one of exemplary purposes of one embodiment of the present invention is to provide a moving object having a simple structure.

  One embodiment of the present invention relates to a moving object. The moving body is an inner tube that is closed at one end and receives an externally controllable pressure at the other end, and a telescopic member that expands in the radial direction by pressurization and contracts in the axial direction. And a telescopic member forming a plurality of chambers in the directions. The inner tube has at least one opening for each chamber. Assuming that the axial length of the chamber-chamber is L and the total area of at least one opening corresponding to the chamber-chamber is S, the ratio S / L of each of the plurality of chamber-chambers is different.

  According to this aspect, by controlling the pressure of one system supplied to the other end of the inner tube, the plurality of chambers can be expanded and contracted at different timings according to the magnitude of the ratio S / L. Thus, the moving body can be deformed like an earthworm to generate a propulsive force.

  The elastic member may be tubular, and the inner tube may be inserted into the elastic member. The inner wall of the expandable member and the outer wall of the inner tube may be in close contact with each other at the boundary between each of the plurality of chambers.

  The length L may be shorter at the tip, and the area S may be larger at the tip. As a result, a large propulsive force in the distal direction can be obtained.

The inner tube may have an openable / closable valve that separates an upstream portion and a downstream portion for each of the second and subsequent chambers from the tip, and openings may be provided in the upstream portion and the downstream portion, respectively.
Thus, the direction in which the propulsive force is generated can be switched according to the opening and closing of the valve.

The inner tube may be switchable between a state in which the area S is larger in the front end chamber-chamber and a state in which the area S is larger in the rear end chamber-chamber.
Thus, the direction in which the propulsive force is generated can be switched.

  Any combination of the above components is also effective as an aspect of the present invention.

  According to an embodiment of the present invention, a moving object having a simple structure can be provided.

FIG. 1A is a cross-sectional view of a moving body according to the first embodiment, and FIG. 1B is an external view thereof. FIGS. 2A to 2G are diagrams for explaining the operation of the moving object in FIG. FIGS. 3A to 3G are diagrams illustrating the operation of another moving object. FIGS. 4A to 4C are diagrams showing design examples of the area S _i and the length L _i . FIGS. 5A to 5C are diagrams illustrating a design example of the area S when S ₁ > S ₂ > S ₃ . 6A to 6D are diagrams illustrating a method of manufacturing a moving body. FIGS. 7A to 7C are cross-sectional views of a moving object according to the second embodiment. It is sectional drawing which shows an example of a valve and its control mechanism. FIGS. 9A and 9B are cross-sectional views of a moving object according to the third embodiment.

  Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and the repeated description will be omitted as appropriate. In addition, the embodiments do not limit the invention, but are exemplifications, and all features and combinations described in the embodiments are not necessarily essential to the invention.

(First Embodiment)
FIG. 1A is a cross-sectional view of the moving body 1 according to the first embodiment, and FIG. 1B is an external view thereof. The moving body 1 is a flexible linear actuator, and is propelled while deforming like an earthworm. The moving body 1 includes a telescopic member 10 and an inner tube 20. The dimensions of each member shown in the drawings are appropriately enlarged or reduced for easy understanding and simplified explanation.

  The elastic member 10 expands in the radial direction by pressurization from the inside, and contracts in the axial direction. As the elastic member 10 having such properties, a McKibben-type pneumatic rubber artificial muscle or a tube having a similar structure can be used. The material of the tube is not particularly limited, but for example, a tube made of silicone rubber can be used.

  One end (also referred to as a tip) 22 of the inner tube 20 is closed. The control unit 2 is connected to the other end (also referred to as a rear end) 24 of the inner tube 20 so that the pressure (flow rate and direction of air) at the rear end 24 can be controlled from the outside. For example, the control unit 2 may include a pneumatic pump or a compressor, and a pressure control valve.

  The elastic member 10 forms a plurality of chambers 40_1 to 40_N in the axial direction outside the inner tube 20. The chamber-chamber 40_1 is located at the forefront, and the chamber-chamber 40_N is located at the rearmost end. FIG. 1 illustrates N = 3, but N is arbitrary.

  For example, the elastic member 10 is tubular, and the inner tube 20 is inserted into the elastic member 10. The inner wall of the elastic member 10 and the outer wall of the inner tube 20 are in close contact with each other at the boundary between the plurality of chambers 40_1 to 40_3. For example, the moving body 1 may include an annular restraining member 50 that presses the elastic member 10 from the outside in the radial direction. As the restraining member 50, a thread, a string, rubber, a metal wire, or the like can be used, and its material is not particularly limited. Alternatively, the inner wall of the elastic member 10 and the outer wall of the inner tube 20 may be bonded or welded at the boundary of the adjacent chamber-chamber 40.

  The inner tube 20 has at least one opening 26_i for each chamber-chamber 40_i (i = 1, 2,... N). Here, one opening 26 is provided for each chamber-chamber 40 in order to simplify the explanation for facilitating understanding. The flow path 21 inside the inner tube 20 communicates with the corresponding chamber 40_i via the opening 26_i.

i-th chamber - when the total area of the at least one opening corresponding to the chamber 40_i 26_I and _{S i,} a plurality of chambers - - axial length _{L i} of the chamber 40_i, that chamber ratio in each chamber 40_i _{S i} / _Li are different. Preferably, the ratio S _i / L _i varies monotonically in the axial direction.

  The above is the configuration of the moving body 1. Subsequently, the operation will be described.

1. S _i / L _i ≧ S _j / L _j (i <j)
2A to 2G are diagrams for explaining the operation of the moving body 1 in FIG. For the two chambers 40_i, 40_j (i <j), it is assumed that S _i / L _i ≧ S _j / L _j is satisfied. The moving body 1 propels the inside of the pipeline 100 rightward. FIG. 2A shows an initial state. When the inner tube 20 is pressurized by the control unit 2, air flows into the chamber 40 through the opening 26 of the inner tube 20. Assuming that the air pressure inside the inner tube 20 is constant, the flow rate of the air flowing into each chamber-chamber 40 is proportional to the area S of the opening 26 corresponding to the chamber-chamber 40. The rate of expansion of the chamber-chamber 40 is proportional to its flow rate per unit volume. Assuming that the inner diameter of the elastic member 10 is uniform, the volume of each chamber is proportional to the axial length L. Therefore, each of the chambers 40_i expands at an expansion speed corresponding to the ratio S _i / L _i .

That is, as shown in FIG. 2B, the chamber-chamber 40_1 on the tip end 22 side having the large ratio S _i / L _i expands first. The expanded chamber-chamber 40_1 comes into contact with the inner wall 102 of the conduit 100, so that the position in the propulsion direction (axial direction) is fixed. When the chamber-chamber 40_1 expands, the length of the chamber-chamber 40_1 becomes shorter due to the property of the elastic member 10, and the succeeding chamber-chambers 40_2 and 40_3 are drawn forward. When the pressurization is further continued, as shown in FIG. 2C, the second chamber-chamber 40_2 expands, its length becomes shorter, and the succeeding chamber-chamber 40_3 is drawn forward. Then, as shown in FIG. 2D, all the chambers 40_1 to 40_3 are in an expanded state.

Subsequently, the control unit 2 switches the inner tube 20 to a reduced pressure state. Then, as shown in FIG. 2E, the chamber-chamber 40_1 on the tip end 22 side having a large ratio S _i / L _i contracts first. When the chamber-chamber 40_1 contracts, the length of the chamber-chamber 40_1 becomes longer due to the property of the elastic member 10, and the chamber-chamber 40_1 is extended in the axial direction. When the pressure is further reduced, the second chamber-chamber 40_2 contracts as shown in FIG. 2 (f), its length becomes longer, and the chamber-chambers 40_1 and 40_2 are extended in the axial direction. When the pressure is further reduced, the third chamber-chamber 40_3 contracts as shown in FIG. 2 (g), its length becomes longer, and the chamber-chambers 40_1 to 40_3 are extended in the axial direction. By repeating pressurization and depressurization by the control unit 2, the operations in FIGS. 2A to 2G are repeated, and the moving body 1 is propelled rightward, that is, toward the tip end 22.

  In addition, here, for clarity, the state in which the chambers 40_1 to 40_3 expand and contract in order is shown. May be expanded, and conversely, while the chamber-chamber 40_1 is contracted, the chamber-chambers 40_2, 40_3 may also contract.

2. S _i / L _i ≦ S _j / L _j (i <j)
FIGS. 3A to 3G are diagrams illustrating the operation of another moving body 1. Here, S _i / L _i ≦ S _j / L _j holds for the two chamber-chambers 40 — _i and 40 — j that satisfy i <j. In this case, the order of expansion and contraction of the plurality of chambers / chambers 40 is opposite to the order shown in FIGS. Thereby, the moving body 1 is propelled to the left, that is, to the rear end 24 side.

The above is the operation of the mobile unit 1. According to the moving body 1, by giving a gradient to the ratio S _i / L _i , only the pressure of one system to the inner tube 20 is controlled, and the plurality of chambers 40 _ 1 to 40 _ 3 are sequentially expanded and expanded. The moving body 1 can be deformed like an earthworm, thereby generating a propulsive force.

  Further, as described in FIGS. 2 and 3, the direction of the propulsion force can be designed according to the direction of the gradient. Further, the propulsion force and the propulsion speed can be designed based on the area S of the opening 26 and the length L of the space. Furthermore, in the moving body 1, the plurality of chambers 40 can be controlled by one system of air pressure source, and the cost and size can be significantly reduced as compared with the conventional moving body.

FIGS. 4A to 4C are diagrams showing design examples of the area S _i and the length L _i . Figure 4 (a), the length _L 1 ~L ₃ are _equal, are made up is _{S 1> S 2> S 3} .

In FIG. 4B, the areas S _{1 to} S ₃ are equal, and L ₁ <L ₂ <L ₃ holds. In FIG. 4C, S ₁ > S ₂ > S ₃ and L ₁ <L ₂ <L ₃ hold. When the traveling direction is reversed, the direction of the inequality sign may be reversed.

FIGS. 5A to 5C are diagrams illustrating a design example of the area S when S ₁ > S ₂ > S ₃ . In FIG. 5A, one opening having a different area is provided in each chamber-chamber 40. In FIG. 5B, different numbers of openings of the same size are provided. In FIG. 5C, different numbers of openings of different sizes are provided. Alternatively, as shown in FIG. 6A described later, a plurality of openings of different sizes may be provided in the same number.

  Subsequently, an example of a specific method for manufacturing the moving body 1 will be described. FIGS. 6A to 6D are diagrams illustrating a method of manufacturing the moving body 1. As shown in FIG. 6A, a plurality of openings 26_1 to 26_3 are formed in the inner tube 20. For example, the opening 26 may be formed using a needle-shaped device.

  An example of a method for manufacturing the elastic member 10 will be described with reference to FIG. Silicon (for example, Ecoflex00-50: registered trademark) 14 is applied to the surface while rotating the carbon tube 12 to produce a silicon tube. Then, the yarn 16 is wound around the surface of the silicon tube so as to form a mesh structure like McKibben. Then, the silicon 14 is impregnated into the yarn 16 to reduce the pressure (negative pressure), and the silicon 14 is coated on the yarn 16 and cured. As the elastic member 10, commercially available McKibben-type artificial muscle rubber may be used.

  As shown in FIG. 6C, the inner tube 20 is inserted into the elastic member 10. Then, as shown in phrase 6 (d), the restricting member 50 is attached so that the elastic member 10 is in close contact with the inner tube 20 at each boundary of the plurality of chambers-chambers 40. For example, the restraining member 50 may be a nylon fiber, a polyamide-based synthetic fiber, or a metal wire such as a wire or a piano wire.

  The above is the method of manufacturing the moving body 1. The prototype of the moving body 1 manufactured by the present inventor by this manufacturing method had a weight of 2.5 g, a length of 18.5 cm, an inner diameter of the elastic member 10 of 2 mm, and an outer diameter of 4 mm. With this prototype, propulsion in a conduit with an inner diameter of 6 mm to 8 mm has been confirmed, and a moving speed of 8 mm / sec (50 cm / min) has been obtained, making it practical for medical use including active catheters. Is high.

  In this prototype, the expansion member 10 could not expand sufficiently in the conduit 100 having an inner diameter smaller than 6 mm, and a reduction in propulsion force was observed. In other words, the diameter of the elastic member 10 may be optimized in consideration of the inner diameter of the conduit 100.

(Second embodiment)
In the first embodiment, the ratio S / L is fixed, so that the traveling direction is constant. In the second embodiment, a configuration in which the traveling direction can be switched will be described.

  FIGS. 7A to 7C are cross-sectional views of a moving body 1a according to the second embodiment. The inner tube 20a has openable / closable valves 66_2 to 66_3 that partition the upstream portion 62 and the downstream portion 64 in the chambers 40_2 to 40_3 (40_N). In the chambers 40_2 to 40_3, the inner tube 20a is provided with openings 68 and 70 in the upstream portion 62 and the downstream portion 64, respectively.

FIG. 7B shows a state where the valves 66_2 and 66_3 are open. The state where the valves 66_2 and 66_3 are open is equivalent to the inner tube 20 of FIG. In each of the chambers 40_2 (40_3), the total area of the openings 68 upstream and downstream of the valve 66_2 (66_3) is an effective opening area S ₂ (S ₃ ). Therefore, S ₁ > S ₂ > S ₃ holds, and the moving body is propelled in the direction of the tip end 22 as shown in FIG.

  FIG. 7C shows a state where the valves 66_2 and 66_3 are closed. In the pressurized state, air flows into the chamber-chamber 40_3 from the opening 68 in the chamber-chamber 40_3. Thereby, the chamber-chamber 40_3 starts to expand first. When the expansion is completed and the pressure in the chamber-chamber 40_3 increases, air flows from the opening 70 into the flow path 21 of the inner tube 20.

  Subsequently, air flows into the chamber-chamber 40_2 from the opening 68. Thereby, the chamber-chamber 40_2 starts to expand. When the expansion is completed and the pressure in the chamber-chamber 40_2 increases, air flows into the flow path 21 of the inner tube 20 from the opening 70.

  Subsequently, air flows into the chamber-chamber 40_1 from the opening 26_1. Thereby, the chamber-chamber 40_1 starts to expand.

  After all the chambers 40_1 to 40_3 have expanded, decompression is started at the rear end 24. As a result, the size is reduced in the order of the chambers 40_3, 40_2, and 40_1. Thus, the expansion and contraction of the plurality of chambers 40 are controlled in the same order as in FIGS. 3A to 3G, so that the moving body can be retracted.

  As described above, according to the moving body 1a according to the second embodiment, the traveling direction can be switched by controlling the states of the valves 66_2 and 66_3.

  FIG. 8 is a sectional view showing an example of the valve 66 and its control mechanism. The channel 21 has a large diameter at a portion corresponding to the valve 66. The valve 66 includes a valve element (also referred to as a stopper) 72 in the thick portion 23. The valve body 72 may be a sphere (ball), and the diameter of the valve body 72 is smaller than the inside diameter of the portion 23 and larger than the inside diameter of the flow path 21. The boundary between the portion 23 and the flow path 21 corresponds to a valve seat. The valve bodies 72 of the plurality of valves 66 are connected by a connecting member 74, and the connecting member 74 is drawn out from the rear end 24 of the inner tube 20a. The connecting member 74 may be a string, a thread, or a metal wire.

  FIG. 8 shows a state in which the valve 66 is open by a solid line. When the connecting member 74 pulled out from the rear end 24 of the inner tube 20a is pulled leftward, the valve body 72 moves to a position indicated by a dashed line. Thus, the flow path 21 is closed by the valve body 72, and the valve 66 is closed.

  According to the configuration of FIG. 8, the opening and closing of the plurality of valves 66 can be mechanically and easily controlled from the outside. The structure of the valve is not particularly limited, and a known valve structure can be adopted.

(Third embodiment)
FIGS. 9A and 9B are cross-sectional views of moving bodies 1b and 1c according to the third embodiment. These mobile 1b, 1c, like the second embodiment, but may be traveling direction switching, a plurality of chambers for its - the area _S 1 to S ₃ of the opening of the chamber 40_1～40_3 26_1～26_3 , Can be physically changed. The inner tube 20b is specifically, an opening area S is the tip of the chamber - the higher chamber 40_1 larger state _{(S 1> S 2> S} 3), the chamber of the rear end - as chamber 40_N larger state _(S 3> S ₂ > S ₁ ).

  The inner tubes 20b and 20c have a two-layer structure having an inner tube 80 and an outer tube 82. The inner tube 80 is slidable inside the outer tube 82. An opening 84 is provided in the inner tube 80, and an opening 86 is provided in the outer tube 82, and at least one of their positions, sizes, and shapes is different. The overlap between the openings 84 and 86 forms the opening 26.

  In FIG. 9A, the inner tube 80 is slidable in the length direction (axial direction), and the area of the opening 26 changes according to the sliding, so that the inner tube 80 can be switched between forward and backward.

  In FIG. 9B, openings 84a and 84b having different sizes are formed on the upper side and the lower side of the inner tube 80, respectively. The outer tube 82 is rotatable in the circumferential direction, and its opening 86 can be switched between a state of overlapping with the opening 84a and a state of overlapping with the opening 84b, and can switch between forward and backward in accordance with the rotation. it can. The relationship between the inner tube 80 and the outer tube 82 is relative, and the outer tube 82 may be moved relative to the inner tube 80, or the inner tube 80 may be moved relative to the outer tube 82.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and that such modifications are also within the scope of the present invention. is there. Hereinafter, such modifications will be described.

  In some embodiments described above, the moving body 1 is configured by the combination of the tubular elastic member 10 and the inner tube 20, but the present invention is not limited thereto. The elastic member 10 may be constituted by a plurality of members physically divided for each chamber-chamber 40.

  Although the present invention has been described using specific terms based on the embodiments, the embodiments are merely illustrative of the principles and applications of the present invention, and the embodiments are defined in the appended claims. Many modifications and changes in arrangement may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Moving body, 2 ... Control part, 10 ... Telescopic member, 12 ... Carbon tube, 14 ... Silicon, 20 ... Inner tube, 21 ... Flow path, 22 ... Tip, 24 ... Rear end, 26 ... Opening, 40 ... Chamber -Chamber, 50 ... restraint member, 62 ... upstream part, 64 ... downstream part, 66 ... valve, 68, 70 ... opening, 72 ... valve body, 80 ... inner pipe, 82 ... outer pipe.

Claims (5)

One end is closed, and the other end receives an externally controllable pressure at the other end,
A telescopic member that expands in the radial direction by pressurization and contracts in the axial direction, the telescopic member forming a plurality of chambers in the axial direction outside the inner tube;
With
The inner tube has at least one opening for each chamber-chamber.
Assuming that the axial length of the chamber-chamber is L and the total area of the at least one opening corresponding to the chamber-chamber is S, the ratio S / L of each of the plurality of chamber-chambers is A moving object characterized by being larger in a chamber . The elastic member is tubular, the inner tube is inserted into the elastic member,
2. The moving body according to claim 1, wherein an inner wall of the elastic member and an outer wall of the inner tube are in close contact with each other at a boundary between the plurality of chambers. 3.   The moving body according to claim 1, wherein the length L is shorter at the front end, and the area S is larger at the front end.   The inner tube has an openable / closable valve for separating an upstream portion and a downstream portion for each of the second and subsequent chambers from the tip, and the opening is provided in each of the upstream portion and the downstream portion. The moving body according to claim 1.   4. The inner tube according to claim 1, wherein the inner tube is switchable between a state in which the area S is larger in the front chamber-chamber and a state in which the area S is larger in the rear chamber-chamber. 5. Moving body.

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