In-pipe moving body

Abstract

To increase propulsive force by a telescopic actuator that expands and contracts in a front-rear direction with a change in an internal air pressure with a simple structure.SOLUTION: An in-pipe moving body 11 has a structure capable of being self-propelled within a gas pipe P by being pneumatically driven, and includes a propulsion module 14 that operates so as to be capable of generating propulsive force for moving within the gas pipe P. The propulsion module 14 includes a telescopic actuator 17 that is telescopically deformable in a front-rear direction. The telescopic actuator 17 comprises an elastic tube 21 arranged along a front-rear direction and elastically deformable by adjusting an internal air pressure, and a reverse-wound meshing spring 24 that biases the elastic tube 21 in a contraction direction. The reverse-wound meshing spring 24 is arranged to allow deformation of the elastic tube 21 only in the front-rear direction, and is configured to be capable of restricting a rotational motion of the elastic tube 21 during the deformation.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an in-pipe moving body having a structure that can move like an inchworm inside a tubular body by being driven by air pressure. [Background technology]

[0002] In recent years, countermeasures against the deterioration of social infrastructure have become increasingly important in Japan. This requires preventive maintenance inspections that prevent accidents by detecting abnormalities early and taking prompt action, as well as taking measures before major repairs are required. However, most lifelines are buried under roads, making it unrealistic to occupy roads and excavate them solely for the purpose of inspecting the inside of these pipes. Gas infrastructure, however, is particularly in need of development of inspection technology, as gas pipes buried underground during the period of rapid economic growth have aged and become aged pipes. Gas infrastructure inspections require an inspection device that can detect the internal condition of gas pipes without shutting off the gas supply or excavating roads. The inventors have already proposed an in-pipe mobile vehicle for pipe inspection (see Patent Document 1).

[0003] This intra-pipe moving body is inserted into a gas pipe from an open section of the outdoor gas pipe and is pneumatically driven to move inside the gas pipe like an inchworm. It includes a bending module at the front end that selects the branch direction and a propulsion module that generates propulsion force for moving inside the gas pipe. The propulsion module is composed of a tubular telescopic actuator that can expand and contract in the forward and backward directions due to changes in the internal air pressure, and a pair of balloons provided on both the front and rear sides of the telescopic actuator. Air is supplied to and exhausted from the telescopic actuator and balloons from a ground-based pump through an air supply tube, so the intra-pipe moving body moves inside the gas pipe while pulling the air supply tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-48488 Summary of the Invention [Problem to be solved by the invention]

[0005] The intra-pipe moving body of Patent Document 1 is inserted from outdoors and self-propels itself through the gas pipe while towing the air supply tube by telescopic motion using a telescopic actuator when inspecting the inside of a main or branch pipe buried underground, such as under a road. Here, gas pipes have many bends, branches, and steps. However, if the travel distance of the intra-pipe moving body is sufficiently short, the tension of the air supply tube that needs to be taken into consideration when towing is small. However, when the intra-pipe moving body penetrates deep into the main or branch pipe, friction with the pipe wall in the many curved sections and long, straight pipes increases the tension of the air supply tube. Therefore, the telescopic actuator of Patent Document 1 may not provide enough propulsion force to move the intra-pipe moving body while towing the air supply tube.

[0006] The present invention was devised with an eye on these problems, and its purpose is to provide an in-pipe moving body with a simple structure that can increase the propulsive force generated by an extendable actuator that extends and contracts in the forward and backward directions in response to changes in the internal air pressure. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention is mainly an in-pipe moving body having a structure that can self-propel within a tubular body by air pressure drive, and includes a propulsion module that operates to generate propulsion force for moving within the pipe, the propulsion module having an extension actuator that is arranged to be able to expand and contract in the front-to-back direction, the extension actuator having an elastic tube that is arranged along the front-to-back direction and can elastically deform by adjusting the air pressure inside, and a biasing member that biases the elastic tube in the contraction direction, the biasing member being arranged to allow deformation of the elastic tube only in the front-to-back direction, and being configured to be able to restrict the rotational movement of the elastic tube during said deformation.

[0008] In the claims and this specification, the term "front" indicating a position or direction means "front" in the direction of travel of the intra-tube moving body as it moves toward the back of the tubular body, unless otherwise specified, and "rear" means "rear" in the same direction of travel. [Effects of the Invention]

[0009] According to the present invention, when the telescopic actuator contracts to pull an air supply tube or the like following the intra-pipe moving body, a stronger propulsive force can be obtained by utilizing the biasing force of the biasing member provided in the telescopic actuator. Therefore, with a simple structure that simply provides a biasing member, it is possible to move the intra-pipe moving body more smoothly while pulling the air supply tube in a state of increased tension, compared to intra-pipe moving bodies with the inventors' previous structure. Furthermore, the biasing member restricts radial deformation of the elastic tube due to changes in air pressure within the elastic tube, and restricts rotational movement of the elastic tube during elastic deformation, thereby more efficiently improving the propulsive force generated by the telescopic actuator. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a piping inspection device including an in-pipe moving body according to an embodiment of the present invention; [Figure 2] (A) is a schematic diagram of an intra-tube moving body including a schematic cross-sectional view of a propulsion module, (B) is a schematic cross-sectional view of a rear balloon in a direction along line AA of (A), and (C) is a schematic cross-sectional view of a front balloon in a direction along line BB of (A). [Figure 3] FIG. 1A is a schematic front view of a pair of close-coupled coil springs with different winding directions before meshing, and FIG. 1B is a schematic perspective view of a reverse-wound meshing spring after the close-coupled coil springs of FIG. 1A have been meshed. [Figure 4] 10(A) to 10(F) are conceptual diagrams for explaining each operation phase of an intra-pipe moving body. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] 1 shows a schematic diagram of a pipe inspection robot including an in-pipe mobile body according to this embodiment. In this figure, the pipe inspection robot 10 includes an in-pipe mobile body 11 that is pneumatically driven and capable of self-propelling within a tubular gas pipe P, and a power supply unit 12 that is disposed on the ground outside the gas pipe P and supplies and exhausts compressed air as a power source to the in-pipe mobile body 11. The pipe inspection robot 10 of this embodiment is used to collect information about the inside of the gas pipe P while the in-pipe mobile body 11 self-propels within the gas pipe P buried underground, and to monitor conditions such as the occurrence of abnormalities within the gas pipe P from the ground.

[0013] The intra-pipe moving body 11 is structured so that it can move like an inchworm inside the gas pipe P while appropriately contacting a part of it with the inner wall of the gas pipe P by adjusting the supply and exhaust of air using a power supply unit 12. The intra-pipe moving body 11 includes a propulsion module 14 that operates to generate propulsive force for moving inside the gas pipe P, and a bending module 15 that is bendably connected to the front end side of the propulsion module 14.

[0014] The propulsion module 14 is composed of a telescopic actuator 17 that is provided so as to be able to extend and retract in the front-rear direction, and a front balloon 18 and a rear balloon 19 that are connected to the front and rear of the telescopic actuator 17, respectively.

[0015] As shown in FIG. 2(A), the telescopic actuator 17 includes an elastic tube 21 arranged along the front-to-rear direction and elastically deformable by adjusting the air pressure inside, plugs 22 attached so as to be able to close the front and rear open portions of the elastic tube 21, a cover 23 covering the outer surface of the elastic tube 21, and a reverse-wound meshing spring 24 wound around the outer surface of the cover 23 and serving as a biasing member formed by meshing coil springs with different winding directions.

[0016] The elastic tube 21 is made of an elastic body such as rubber, and has formed therein a closed space S into which air can be supplied or discharged by the operation of the power supply unit 12. Therefore, the elastic tube 21 can expand or contract by the operation of the power supply unit 12 pressurizing or depressurizing the air in the closed space S at a predetermined timing.

[0017] The cover 23 is disposed between the outer peripheral surface of the elastic tube 21 and the reverse-wound meshing spring 24, and is formed of an expandable material (such as nylon) that prevents the elastic tube 21 from getting caught in the gaps of the reverse-wound meshing spring 24 due to deformation of the elastic tube 21. This makes it possible to prevent interference with the reverse-wound meshing spring 24 when the elastic tube 21 expands or contracts.

[0018] 3, the reverse-wound meshing spring 24 is formed by alternately meshing one winding of a pair of close-coupled coil springs 24A, 24B (see FIG. 3(A)), one wound clockwise and the other wound counterclockwise, with the springs wound in opposite directions. The reverse-wound meshing spring 24 (see FIG. 3(B)) after meshing has a total length slightly longer than the sum of the lengths of the close-coupled coil springs 24A, 24B in an unbiased state, and is initially fixed to the outer circumferential sides of the elastic tube 21 and the cover 23 so as not to move relative to each other in an extended biased state of the close-coupled coil springs 24A, 24B.

[0019] According to the above configuration, when the elastic tube 21 expands due to the supply of compressed air, the elastic tube 21 is deformed so that its radial elastic deformation is restricted by the reverse-wound meshing spring 24 wound around its outer periphery, and it expands only in the axial direction, and the telescopic actuator 17 as a whole expands in the front-to-rear direction (axial direction) from a predetermined reference length. Then, when the elastic tube 21 contracts from this expanded state due to the discharge of compressed air, the telescopic actuator 17 contracts in the axial direction as a whole due to the elastic recovery of the elastic tube 21 and the restoring force of the reverse-wound meshing spring 24, and returns to the reference length. Note that when the power supply unit 12 maintains the pressure in the closed space S inside the elastic tube 21, the length of the telescopic actuator 17 at that time is maintained.

[0020] Furthermore, by using the reverse-wound meshing spring 24 as the biasing member, rather than a simple coil spring, the rotational movement around the axis of the telescopic actuator 17 when it is extended or retracted is restricted. That is, if a coil spring with only one winding direction is used, an external force acts in the radial direction of the coil spring due to the expansion of the elastic tube 21 inside the coil spring. This external force causes the telescopic actuator 17 to rotate along the winding direction of the coil spring, making the intra-pipe mover 11 prone to twisting as a whole and preventing smooth movement. In this regard, by using the reverse-wound meshing spring 24 formed by meshing the close-contact coil springs 24A, 24B with mutually different winding directions, the rotation of the close-contact coil springs 24A, 24B when the elastic tube 21 is expanded is offset, restricting the twisting of the intra-pipe mover 11 when it moves.

[0021] As shown in Figure 2, the front balloon 18 and the rear balloon 19 each comprise an elastic tube 26 made of an elastic material such as rubber that can be elastically deformed by adjusting the air pressure inside, plugs 27 attached so as to be able to close the front and rear open portions of the elastic tube 26, and a casing tube 28 that is disposed in the center of the interior space of the elastic tube 26 and that restricts the bending radius to prevent bending due to external forces. These balloons 18, 19 can be expanded and contracted overall in both the radial and axial directions of the elastic tube 26 by pressurizing or depressurizing the air in the internal closed space S outside the casing tube 28 within the elastic tube 26 at a predetermined timing by the power supply unit 12. As will be described later, air is supplied to and discharged from the front balloon 18 and the rear balloon 19 at mutually independent timings.

[0022] A connecting shaft 29 passes through the front part of the closed space S of the expansion and contraction actuator 17 configured as described above, near the center of the inside of the front balloon 18, and the connecting shaft 29 is connected to the bending module 15 in front of the front balloon 18.

[0023] The propulsion module 14 configured as described above sequentially repeats the six operating phases of the in-pipe moving body 11 shown in Figure 4 as one cycle, making it possible to move the in-pipe moving body 11 forward toward the depths of the gas pipe P, with the bending module 15 side at the forefront, as follows.

[0024] First, in the first phase of Fig. 4(A), the rear balloon 19 on the left side of the figure is pressurized and inflated, and is pressed against the inner wall of the gas pipe P, thereby engaging with the inner wall. Meanwhile, the front balloon 18 on the right side of the figure is depressurized and in its most deflated state, and is in an unlocked state where it is not in contact with the inner wall of the gas pipe P. Furthermore, the telescopic actuator 17 is depressurized and in the state of the shortest reference length.

[0025] From this state, in the second phase of the figure (B), the expansion actuator 17 of the reference length is pressurized and expands in the axial direction. At this time, the rear balloon 19 is maintained in the locked state with its internal pressure maintained, while the front balloon 18 is maintained in the unlocked state, so the expansion actuator 17 expands forward.

[0026] Next, in the third phase shown in Fig. 1C, the front balloon 18 is pressurized and changes to the state of being locked to the inner wall. At this time, the expansion / contraction actuator 17 and the rear balloon 19 are maintained in the same state as in the second phase.

[0027] Furthermore, in the fourth phase shown in Fig. 1(D), the rear balloon 19 is depressurized and deflated, and the engagement with the inner wall is released, resulting in the aforementioned unlocked state. At this time, the expansion / contraction actuator 17 and the front balloon 18 are maintained in the same state as in the third phase.

[0028] Then, in the fifth phase of the figure (E), the expansion actuator 17 is decompressed and contracts, and its elasticity and the restoring force of the reverse-wound meshing spring 24 (see Figure 1, etc.) cause it to return to its original standard length. At this time, since the front balloon 18 is maintained in the locked state while the rear balloon 19 is maintained in the unlocked state, the expansion actuator 17 contracts forward.

[0029] From this state, in the sixth phase of FIG. 1(F), the front balloon 18 is depressurized again to the unlocked state as shown by the solid line in the figure, and then returns to the first phase in which the rear balloon 19 is pressurized while the state of the expansion / contraction actuator 17 is maintained, and the above phases are repeated. Such operation in the sixth phase is applied when the intra-pipe movable body 11 moves in a gas pipe P extending horizontally (horizontal pipe). On the other hand, the operation in the sixth phase when the intra-pipe movable body 11 moves in a gas pipe P extending vertically (vertical pipe) is set differently from when moving in a horizontal pipe to prevent the intra-pipe movable body 11 from falling inside the gas pipe due to gravity. That is, when moving in the vertical pipe, the front balloon 18 and the rear balloon 19 are pressurized, and the front balloon 18 and the rear balloon 19 are each set to the locked state as shown by the dashed line in the figure. Then, while the state of the expansion / contraction actuator 17 is maintained, the process returns to the first phase in which the front balloon 18 is decompressed, and the above-mentioned phases are repeated.

[0030] If the above-described operation phases are performed in reverse order, the intra-pipe mover 11 moves in the gas pipe P in the direction opposite to that described above, and the intra-pipe mover 11 can move backward.

[0031] The bending module 15 (see FIG. 1) is powered by the air supply and exhaust from the power supply unit 12 (see FIG. 1) and is equipped with an underactuated mechanism that enables bending in any direction relative to the propulsion module 14. Specifically, as shown in FIG. 2(A), the bending module 15 is composed of a rocket-shaped tip 15A that narrows toward the front end and three pneumatic cylinders 15B that bend the tip 15A relative to the propulsion module 14, and the branching direction is selected by bending the tip 15A by driving the pneumatic cylinders 15B. Although not shown, a camera capable of photographing the space inside the gas pipe in front of the intra-pipe moving body 11 is disposed on the tip 15A, and image data acquired by the camera is transmitted to the outside.

[0032] As shown in FIG. 1, the power supply section 12 includes a pump unit 31 that supplies and exhausts air, and a control section 32 that controls the supply and exhaust of air by the pump unit 31.

[0033] Although detailed structure of the pump unit 31 is not shown, it is composed of equipment such as a pump and a control valve that enables the supply and exhaust of air to the propulsion module 14 and the bending module 15 through an air supply tube 34 connected to the intra-pipe moving body 11.

[0034] As shown in Figure 2, the air supply tube 34 is configured to be able to supply and exhaust air independently to each of the closed spaces S (see Figure 2) of the telescopic actuator 17, the front balloon 18 and the rear balloon 19, and to each of the air pressure cylinders 15B, and is pulled as the intra-pipe moving body 11 moves. In the same figure, for convenience, the air supply tubes 34 are designated as air supply tubes 34A, three of which (some not shown) are connected to each pneumatic cylinder 15B, two of which (some not shown) are connected to the closed space S of the front balloon 18, and one of which (some not shown) is connected to the closed space S of the telescopic actuator 17 and is designated as air supply tube 34C, and one of which (one not shown) is connected to the closed space S of the rear balloon 19 and is designated as air supply tube 34D. 2(B), inside the rear balloon 19, the air supply tubes 34A to 34C pass through the internal space of the casing tube 28, while the open end of the air supply tube 34D is disposed outside the casing tube 28. Also, as shown in FIG. 2(C), inside the front balloon 18, the connecting shaft 29 and the air supply tube 34A pass through the internal space of the casing tube 28, while the open end of the air supply tube 34B is disposed outside the casing tube 28.

[0035] The control unit 32 is composed of a computer consisting of an arithmetic processing unit such as a CPU and storage devices such as memory and a hard disk, and by controlling the operation of the pump unit 31, it controls the operation of the intra-pipe moving body 11 while adjusting the supply and discharge of air to the propulsion module 14 and the bending module 15.

[0036] According to the above embodiment, the reverse-wound interlocking spring 24 is used for the telescopic actuator 17, which expands and contracts by adjusting the internal air pressure. This allows the spring to exert a stronger restoring force during contraction than a coil spring with the same wire diameter, inner diameter, overall length, and material, and also suppresses the rotational movement of the telescopic actuator 17 during radial deformation of the spring.

[0037] The biasing member applied to the telescopic actuator 17 is not limited to the form of the above embodiment, as long as it is arranged to allow deformation of the elastic tube 21 only in the forward and backward directions and is configured to be able to regulate the rotational movement of the elastic tube 21 when it is deformed.

[0038] In addition, in the above embodiment, an embodiment has been illustrated and described in which the intra-pipe moving body 11 is moved within the gas pipe P for the purpose of inspecting the inside of the gas pipe P, but the present invention is not limited to this and can also be applied to systems for remotely checking the condition of the internal space of other tubular bodies, including other pipes and tunnels.

[0039] Furthermore, the configuration of each part of the device in the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as they provide substantially the same effect. [Explanation of symbols]

[0040] 11 In-pipe moving body 14 Propulsion Module 17 Telescopic Actuator 21 Elastic tube 23 Cover 24 Reverse-wound meshing spring (biasing member) 24A Close Coil Spring 24B close coil spring P Gas pipe (tubular body)

Claims

1. An in-pipe moving body having a structure capable of self-propelling within a tubular body by air pressure drive, a propulsion module operable to generate a propulsive force for movement within the pipe; the propulsion module includes a telescopic actuator that is capable of expanding and contracting in the front-rear direction; The telescopic actuator is an in-pipe moving body characterized by comprising an elastic tube arranged along the front-to-rear direction and elastically deformable by adjusting the air pressure inside, and a biasing member wound around the outer periphery of the elastic tube and formed by alternately meshing coil springs with opposite winding directions.

2. 2. The intra-pipe moving body according to claim 1, wherein the telescopic actuator further comprises a cover disposed between the outer surface of the elastic tube and the biasing member, the cover preventing the elastic tube from getting caught in the biasing member when the elastic tube is deformed.

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