In-pipe moving robot

Abstract

An object of the present invention is to provide an in-pipe moving robot that can surely pass through a bent portion of a pipe. The in-pipe moving robot 1 includes a robot body 10 having at least three telescopic units 11, and a tip posture maintaining unit 20 having a tip body portion 21 that constitutes the tip of the in-pipe moving robot 1, and a pair of elastic bodies 22 and 23 that protrude radially outward from the outer peripheral surface of the tip body portion 21 and are arranged at intervals in the axial direction. The in-pipe moving robot 1 is characterized by having an elastically deformable elastic connection portion 40 provided between the tip posture maintaining unit 20 and the robot body 10.

Description

Technical Field

[0001] The present invention relates to an in-pipe moving robot that moves inside a pipe.

Background Art

[0002] For example, there is known an in-pipe moving robot configured to move inside a meandering pipe such as an air duct for an air conditioner provided in an office building, a factory, a detached house, etc. (see, for example, Patent Document 1). Such an in-pipe moving robot is used for various applications such as cleaning the inside of the pipe and inspecting the inside of the pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As an in-pipe moving robot, there is one provided with a robot body having at least three expansion and contraction units that expand in the radial direction and contract in the axial direction when fluids are respectively supplied, and configured to move inside the pipe by the at least three expansion and contraction units performing peristaltic motion in a predetermined pattern. In such an in-pipe moving robot, in order to be able to smoothly pass through the bent portion of the pipe, it is common to provide a tapered tip portion at the front end of the robot body via a compression spring.

[0005] However, even in a configuration where a tapered tip portion is provided at the front end of the robot body via a compression spring, if there is a step such as a connection portion of an elbow that forms the bent portion on the inner peripheral surface of the bent portion of the pipe, there is a risk that the tip portion will be caught by the step and the in-pipe moving robot will not be able to move forward.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide an in-pipe moving robot capable of reliably passing through a bent portion of a pipe.

Means for Solving the Problems

[0007] The in-pipe moving robot of the present invention includes a robot body having at least three expansion and contraction units that expand in the radial direction and contract in the axial direction when fluid is supplied thereto, and is configured to move inside a pipe by the expansion and contraction units performing peristaltic motion in a predetermined pattern. The in-pipe moving robot includes a tip main body portion that constitutes the tip of the in-pipe moving robot, and a pair of elastic bodies that are each annular in a schematic annular shape centered on the axis of the tip main body portion or have an outer periphery in a regular polygonal shape, project radially outward from the outer peripheral surface of the tip main body portion, and are arranged at intervals in the axial direction. The in-pipe moving robot also includes an elastically deformable elastic connection portion provided between the tip attitude maintaining portion and the robot body. An angular restraint joint portion provided between the elastic connection portion and the robot body, enabling the tip attitude maintaining portion to be bent with respect to the robot body at an angle of less than 90 degrees. It is characterized by having the above. The in-pipe moving robot of the present invention includes a robot body having at least three expansion and contraction units that expand in the radial direction and contract in the axial direction when fluid is supplied respectively. The in-pipe moving robot is configured to move inside a pipe by the expansion and contraction units performing peristaltic motion in a predetermined pattern. The in-pipe moving robot has a tip main body portion constituting the tip of the in-pipe moving robot, a tip attitude maintaining portion having a pair of elastic bodies that are each substantially annular centered on the axis of the tip main body portion or annular with an outer periphery that is a regular polygon, project radially outward from the outer peripheral surface of the tip main body portion, and are spaced apart from each other in the axial direction, and an elastically deformable elastic connection portion provided between the tip attitude maintaining portion and the robot body. A protruding portion that protrudes forward of the pair of elastic bodies of the tip main body portion is housed within a range of a virtual spherical surface that the outer peripheral ends of the pair of elastic bodies each circumscribe over the entire circumference. The in-pipe moving robot of the present invention includes a robot body having at least three expansion and contraction units that expand in the radial direction and contract in the axial direction when fluid is supplied respectively. The in-pipe moving robot is configured to move inside a pipe by the expansion and contraction units performing peristaltic motion in a predetermined pattern. The in-pipe moving robot has a tip main body portion constituting the tip of the in-pipe moving robot, a tip attitude maintaining portion having a pair of elastic bodies that are each substantially annular centered on the axis of the tip main body portion or annular with an outer periphery that is a regular polygon, project radially outward from the outer peripheral surface of the tip main body portion, and are spaced apart from each other in the axial direction, and an elastically deformable elastic connection portion provided between the tip attitude maintaining portion and the robot body. The elastic body on the rear side is more flexible than the elastic body on the front side.

[0011] In the in-pipe moving robot of the present invention, in the above configuration, it is preferable that a camera is provided on the axis of a protruding portion that protrudes forward of the pair of elastic bodies of the tip main body portion.

[0012] In the in-pipe moving robot of the present invention, in the above configuration, it includes an inner cylindrical body formed in a cylindrical shape having elasticity, and an outer cylindrical body formed in a cylindrical shape having elasticity and disposed overlapping the outside of the inner cylindrical body. It has a cover configured such that the frictional resistance generated between the inner cylindrical body and the outer cylindrical body is smaller than the frictional resistance generated between the outer cylindrical body and the inner surface of the pipe, and it is preferable that the cover covers the angle regulating joint portion.

Effects of the Invention

[0013] According to the present invention, it is possible to provide an in-pipe moving robot that can surely pass through a bent portion of a pipe.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

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Figure 8

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Figure 11

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Figure 14

Embodiments for Carrying out the Invention

[0015] Hereinafter, the in-pipe moving robot of the present invention will be exemplified and described in detail with reference to the drawings.

[0016] The in-pipe moving robot 1 according to the first embodiment of the present invention shown in FIG. 1 is configured to move inside a bent tube such as an air duct for an air conditioner provided in, for example, an office building, a factory, a detached house, etc.

[0017] The in-pipe moving robot 1 has a robot body 10, a tip attitude maintaining unit 20, an angle restricting joint unit 30, and an elastic connection unit 40.

[0018] The robot body 10, which is also called an earthworm-type robot, a peristaltic robot, etc., has an elongated form extending along the axis O. The robot body 10 can move inside the tube in the axial direction, that is, in the direction along the axis O. That is, the robot body 10 can move forward inside the tube. Note that the robot body 10 may be configured to be able to move forward and backward inside the tube.

[0019] The robot body 10 includes at least three telescopic units 11 as a drive source for moving inside the tube. In the present embodiment, the robot body 10 includes seven telescopic units 11 (only four telescopic units 11 are shown in FIG. 1). Note that the number of telescopic units 11 can be appropriately changed as long as the robot body 10 includes at least three telescopic units 11.

[0020] The telescopic unit 11 is also called an artificial muscle. The telescopic unit 11 includes a cylindrical portion 11a formed in a cylindrical shape centered on the axis O by an elastic body such as various rubbers. Both axial ends of the cylindrical portion 11a are closed. Inside the cylindrical portion 11a, a plurality of fiber bundles (not shown) having high tensile strength are arranged along the axial direction. Thereby, the cylindrical portion 11a can be elastically deformed so as to expand in the radial direction, but the elastic deformation in the direction of extending in the axial direction is restricted. Therefore, when a fluid such as compressed air is supplied inside the cylindrical portion 11a of the telescopic unit 11, it operates so as to contract in the axial direction while expanding in the radial direction. Further, when the fluid is discharged from the inside of the cylindrical portion 11a of the telescopic unit 11, it contracts in the radial direction due to the elastic force of the cylindrical portion 11a and extends in the axial direction to return to the original shape. Each telescopic unit 11 can operate individually in a predetermined pattern.

[0021] Note that the telescopic unit 11 may have various configurations, such as a so-called McKibben type in which the outside of a cylindrical elastic body is covered with fibers knitted in a sleeve shape, as long as it is configured to contract in the axial direction while expanding in the radial direction when a fluid is supplied.

[0022] Adjacent telescopic units 11 are axially connected to each other by a connecting portion 12. In the present embodiment, the connecting portion 12 is a universal joint (flexible joint). Thereby, the robot body 10 can bend at the portion of the connecting portion 12. Therefore, when the robot body 10 moves inside the pipe, even if the pipe is bent, the space between adjacent telescopic units 11 bends at the connecting portion 12, so that it can move along the bent pipe.

[0023] In the present embodiment, a universal joint is used as the connecting portion 12, but it is not limited to this as long as it can connect adjacent telescopic units 11 so as to be bendable.

[0024] A control unit 14 is connected to the robot body 10 via a pipe 13. The control unit 14 can individually supply fluid to the inside (interior) of the cylindrical portion 11a of each telescopic unit 11 in a predetermined pattern via the pipe 13. By supplying fluid in a predetermined pattern from the control unit 14 to the inside of the cylindrical portion 11a of each telescopic unit 11, the plurality of telescopic units 11 perform peristaltic motion in a predetermined pattern, and the robot body 10 can move inside the pipe.

[0025] FIG. 2 shows an example of the peristaltic motion pattern of the plurality of telescopic units 11 when the robot body 10 moves to one axial side inside the pipe 2, that is, when it moves forward toward the left side in FIG. 2.

[0026] First, as shown in FIG. 2(a), the leftmost (frontmost) telescopic unit 11 and the second telescopic unit 11 from the left in FIG. 2 are contracted axially while being expanded radially. The two radially expanded telescopic units 11 are each in contact with the inner peripheral surface of the pipe 2 over the entire circumference. As a result, the robot body 10 is held axially by the two radially expanded telescopic units 11.

[0027] Next, from the state shown in FIG. 2(a), as shown in FIG. 2(b), the leftmost telescopic unit 11 is returned to its original shape, and the third telescopic unit 11 from the left is contracted axially while being expanded radially. At this time, since the second telescopic unit 11 from the left is in contact with the inner peripheral surface of the pipe 2 and its axial position is held, when the leftmost telescopic unit 11 contracts radially and extends axially to return to its original shape, the left end (front end) of the robot body 10 moves to the left from the position shown in FIG. 2(a). Also, since the third telescopic unit 11 from the left contracts axially while expanding radially with the second telescopic unit 11 from the left in contact with the inner peripheral surface of the pipe 2 and its axial position being held, the right end (rear end) of the robot body 10 also moves to the left from the position shown in FIG. 2(a).

[0028] Next, from the state shown in Fig. 2(b), as shown in Fig. 2(c), the second telescopic unit 11 from the left is returned to its original shape, and the fourth telescopic unit 11 from the left is contracted axially while expanding radially. At this time, since the third telescopic unit 11 from the left is in contact with the inner peripheral surface of the tube 2 and its axial position is maintained, when the second telescopic unit 11 from the left contracts radially and extends axially to return to its original shape, the left end (front end) of the robot body 10 moves further to the left from the position shown in Fig. 2(b). Also, since the fourth telescopic unit 11 from the left contracts axially while expanding radially in a state where the third telescopic unit 11 from the left is in contact with the inner peripheral surface of the tube 2 and its axial position is maintained, the right end (rear end) of the robot body 10 also moves further to the left from the position shown in Fig. 2(b).

[0029] Hereinafter, the telescopic unit 11 is operated in the above pattern until reaching the rightmost telescopic unit 11 in the same procedure. Then, when the pattern reaches the rightmost telescopic unit 11, as shown in Fig. 2(d), first go back and operate the telescopic unit 11 in the above pattern.

[0030] In this way, by causing the plurality of telescopic units 11 to perform peristaltic motion in the above pattern, the robot body 10 can move forward inside the tube 2 toward the left in Fig. 2. Also, by operating the plurality of telescopic units 11 in a pattern that is the left - right reverse of the pattern shown in Fig. 2, the robot body 10 can move backward inside the tube 2 toward the right in Fig. 2. That is, the in - tube moving robot 1 can move forward and backward inside the tube 2 when the robot body 10 performs the above operations.

[0031] Note that the peristaltic motion pattern of the plurality of telescopic units 11 in the robot body 10 is not limited to the above, and any other pattern may be used as long as it can move the robot body 10 or the in - tube moving robot 1 forward and backward.

[0032] As shown in FIG. 1, in this embodiment, a plurality of brushes 15 are provided on the robot body 10 at intervals in the axial direction of the robot body 10. More specifically, brushes 15 are provided at both axial ends of each telescopic unit 11. The plurality of brushes 15 each have a substantially annular shape centered on the axis O of the robot body 10. That is, the plurality of brushes 15 are configured such that a large number of hairs protruding radially outward from the outer peripheral surface of the robot body 10 centered on the axis O are arranged over the entire circumference in the circumferential direction centered on the axis O. The large number of hairs constituting the brush 15 are, for example, flexible and elastically deformable ones made of synthetic resin. The outer diameter of the brush 15 is substantially the same as the inner diameter of the pipe 2 that the in-pipe moving robot 1 moves in. The outer diameter of the brush 15 is preferably the same as or slightly larger than the inner diameter of the pipe 2 that the in-pipe moving robot 1 moves in. The brush 15 contacts the inner peripheral surface of the pipe 2 at its outer peripheral end when the in-pipe moving robot 1 moves inside the pipe 2.

[0033] By providing a plurality of brushes 15 on the robot body 10, when moving inside the pipe 2, the robot body 10 can move along the pipe 2 while being supported at approximately the center of the pipe 2 by the plurality of brushes 15. Also, by providing a plurality of brushes 15 on the robot body 10, when moving inside the pipe 2, the robot body 10 can collect foreign matters (dirt) such as dust adhering to the inner peripheral surface of the pipe 2 with the brushes 15 and clean the inside of the pipe 2.

[0034] Note that in this embodiment, a plurality of brushes 15 are provided on the robot body 10. However, not limited to the brushes 15, other members such as flange-shaped or umbrella-shaped synthetic rubber having a substantially annular shape centered on the axis O of the robot body 10 may be provided. Also, the robot body 10 may be configured such that no plurality of brushes 15 or other members having a substantially annular shape centered on the axis O of the robot body 10 are provided.

[0035] As shown in FIGS. 1 and 3, the tip attitude maintaining unit 20, the angle regulating joint unit 30, and the elastic connecting unit 40 are provided on the forward direction side (the left side in FIG. 3) with respect to the robot main body 10.

[0036] As shown in FIG. 3, the tip attitude maintaining unit 20 has a tip main body portion 21 and a pair of elastic bodies 22 and 23.

[0037] The tip main body portion 21 is a portion that constitutes the tip (front end) on the forward traveling direction side of the in-pipe moving robot 1. That is, the in-pipe moving robot 1 advances inside the pipe 2 with the tip main body portion 21 at the front. The tip main body portion 21 has a columnar body portion 21a centered on the axis O and a dome-shaped protruding portion 21b centered on the axis O that is continuous with the end portion of the body portion 21a on the forward direction side, and has a tapered shape as a whole. Note that the shape of the tip main body portion 21 is not limited to the above shape.

[0038] The pair of elastic bodies 22 and 23 are each configured in a substantially annular shape centered on the axis O or an annular shape with a polygonal outer periphery, protrude radially outward from the outer peripheral surface of the body portion 21a of the tip main body portion 21, and are arranged at intervals in the axial direction. In the present embodiment, the pair of elastic bodies 22 and 23 are each annular (an annular shape with a circular outer periphery) centered on the axis O. The front elastic body 22 is arranged at the front end portion of the body portion 21a of the tip main body portion 21, and the rear elastic body 23 is arranged on the body portion 21a at a predetermined distance rearward from the front elastic body 22. The axial interval between the pair of elastic bodies 22 and 23 may be appropriately set according to the size of the pipe to be moved, the curvature of the bent portion, etc. The pair of elastic bodies 22 and 23 are each elastically deformable in the axial direction and in the radial direction centered on the axis O.

[0039] In this embodiment, the front elastic body 22 and the rear elastic body 23 have the same shape or configuration as each other. More specifically, the pair of elastic bodies 22 and 23 are each an annular brush centered on the axis O of the body portion 21a. That is, the pair of elastic bodies 22 and 23 are each configured such that a number of hairs protruding radially outward from the outer peripheral surface of the body portion 21a toward the outside in the radial direction centered on the axis O are arranged over the entire circumference in the circumferential direction centered on the axis O. The number of hairs constituting the elastic bodies 22 and 23 are, for example, flexible and elastically deformable ones made of synthetic resin or the like. The outer diameters of the elastic bodies 22 and 23 are substantially the same as the inner diameter of the pipe 2 which is the object for the in-pipe moving robot 1 to move. The outer diameters of the elastic bodies 22 and 23 are preferably the same as or slightly larger than the inner diameter of the pipe 2 which is the object for the in-pipe moving robot 1 to move. The elastic bodies 22 and 23 are in contact with the inner peripheral surface of the pipe 2 at their outer peripheral ends when the in-pipe moving robot 1 moves inside the pipe 2.

[0040] The tip attitude maintaining portion 20 is provided with a pair of elastic bodies 22 and 23 spaced apart in the axial direction on the tip main body portion 21, so that when moving inside the pipe 2, it can move along the pipe 2 while being supported at substantially the center of the pipe 2 by the pair of elastic bodies 22 and 23. Further, when a brush is used as the pair of elastic bodies 22 and 23 provided on the tip main body portion 21, the tip attitude maintaining portion 20 can collect foreign matters (dirt) such as dust adhering to the inner peripheral surface of the pipe 2 by the pair of elastic bodies 22 and 23 and clean the inside of the pipe 2 when moving inside the pipe 2.

[0041] In this embodiment, the pair of elastic bodies 22 and 23 are annular centered on the axis O, but not limited to this. As long as the tip attitude maintaining portion 20 can be supported at substantially the center of the pipe 2, for example, it may be configured in a substantially annular shape such as a D shape with a part of the outer periphery slightly cut, or may be configured in an annular shape with a regular polygon outer periphery. Further, in this embodiment, a brush is used as the pair of elastic bodies 22 and 23, but not limited to this. As long as it has an annular form centered on the axis O of the tip main body portion 21, for example, an annular and elastically deformable member such as a flange-shaped or umbrella-shaped synthetic rubber may be provided with other materials or configurations.

[0042] The tip attitude maintaining part 20 preferably has a configuration in which a protruding part 21b protruding forward from a pair of elastic bodies 22 and 23 of the tip main body part 21 is housed within a range of a virtual spherical surface 24 (indicated by a two-dot chain line in FIG. 3) in which the outer peripheral ends 22a and 23a of the pair of elastic bodies 22 and 23 are inscribed over the entire circumference. The virtual spherical surface 24 has a point 24a on the axis O at the center position between the pair of elastic bodies 22 and 23 arranged at intervals along the axis O as the center point, and is a spherical surface in which the outer peripheral ends 22a and 23a of the pair of elastic bodies 22 and 23 are inscribed. The protruding part 21b of the tip main body part 21 is entirely arranged inside the virtual spherical surface 24 without protruding outside the virtual spherical surface 24.

[0043] In the present embodiment, a camera 25 is provided on the axis O of a protruding part 21b that protrudes forward from a pair of elastic bodies 22 and 23 of the tip main body part 21. More specifically, the protruding part 21b is configured as a transparent dome-shaped cover, and the camera 25 is installed on the axis O inside thereof. The camera 25 is directed forward, and when the in-pipe moving robot 1 moves inside the pipe 2, the inside of the pipe 2 on the front side of the tip main body part 21 can be photographed. The camera 25 can be configured to display a photographed image of the inside of the pipe 2 on a monitor arranged outside the pipe 2, for example. By providing such a camera 25, when the in-pipe moving robot 1 moves inside the pipe 2, the state inside the pipe 2 can be confirmed from the photographed image of the camera 25.

[0044] Note that an illumination device 26 may be provided inside the protruding part 21b so that the inside of the pipe 2 photographed by the camera 25 is illuminated by the light emitted by the illumination device 26. As the illumination device 26, for example, LED illumination can be used.

[0045] The angle restricting joint portion 30 is provided between the tip attitude maintaining portion 20 and the robot body 10. More specifically, the angle restricting joint portion 30 is provided between the elastic connecting portion 40 connected to the rear end portion of the tip attitude maintaining portion 20 and the robot body 10. The angle restricting joint portion 30 is connected so as to be able to bend the tip attitude maintaining portion 20 with respect to the robot body 10 at an angle of less than 90 degrees.

[0046] In the present embodiment, the angle restricting joint portion 30 has a universal joint portion 31 and a stopper portion 32.

[0047] The universal joint portion 31 is a so-called universal joint. The universal joint portion 31 is provided between a front fixing portion 33 fixed to the rear end of the elastic connecting portion 40 and a rear fixing portion 34 fixed to the front end of the robot body 10, and the front fixing portion 33 and the rear fixing portion 34 are rotatable relative to each other about a front rotation axis 35 perpendicular to the axis O, and are connected so as to be rotatable about a rear rotation axis 36 perpendicular to the axis O and the front rotation axis 35.

[0048] The stopper portion 32 is supported by the universal joint portion 31 and provided between the front fixing portion 33 and the rear fixing portion 34. The stopper portion 32 is configured to abut against the front fixing portion 33 when the front fixing portion 33 rotates by a predetermined angle of less than 90 degrees about the front rotation axis 35 with respect to the axis O. Thereby, the rotation angle, that is, the bending angle, of the front fixing portion 33 about the front rotation axis 35 with respect to the axis O is restricted to less than 90 degrees by the stopper portion 32. Further, the stopper portion 32 is configured to abut against the rear fixing portion 34 when the rear fixing portion 34 rotates by a predetermined angle of less than 90 degrees about the rear rotation axis 36 with respect to the axis O. Thereby, the rotation angle, that is, the bending angle, of the rear fixing portion 34 about the rear rotation axis 36 with respect to the axis O is restricted to less than 90 degrees by the stopper portion 32.

[0049] Incidentally, the angle-regulating joint portion 30 may have various configurations as long as it is provided between the tip attitude maintaining portion 20 and the robot body 10 and connects the tip attitude maintaining portion 20 so as to be bendable at an angle of less than 90 degrees with respect to the robot body 10, and is not limited to the configuration including the universal joint portion 31 and the stopper portion 32 described above. Further, a configuration in which the angle-regulating joint portion 30 is not provided may also be adopted.

[0050] The elastic connection portion 40 is provided between the tip attitude maintaining portion 20 and the angle-regulating joint portion 30, and connects the tip attitude maintaining portion 20 and the angle-regulating joint portion 30. When the angle-regulating joint portion 30 is not provided, the elastic connection portion 40 is provided between the tip attitude maintaining portion 20 and the robot body 10, and connects the tip attitude maintaining portion 20 and the robot body 10.

[0051] In the present embodiment, the elastic connection portion 40 is constituted by a compression coil spring extending along the axis O. The elastic connection portion 40 can be elastically deformed so as to contract along the axis O. Further, the elastic connection portion 40 can be elastically deformed flexibly so as to bend with respect to the axis O. Therefore, when the tip attitude maintaining portion 20 approaches the bent portion 2b of the tube 2, the elastic connection portion 40 is elastically deformed so as to bend with respect to the axis O, whereby the tip attitude maintaining portion 20 can bend in the direction along the bent portion 2b with respect to the angle-regulating joint portion 30.

[0052] The elastic connection portion 40 is not limited to the compression coil spring described above, and may be other members such as a rubber tube as long as it is provided between the tip attitude maintaining portion 20 and the angle-regulating joint portion 30 to connect them and can be elastically deformed so as to bend with respect to the axis O between the tip attitude maintaining portion 20 and the angle-regulating joint portion 30.

[0053] As shown in FIG. 4, the in-pipe moving robot 1 according to the present embodiment can surely pass through the bent portion 2b even if the tube 2 through which the in-pipe moving robot 1 moves has a bent portion 2b between a pair of straight portions 2a.

[0054] That is, in the in-pipe moving robot 1 according to the present embodiment, a pair of elastic bodies 22 and 23 arranged at an axial interval are provided on the tip main body portion 21 of the tip posture maintaining portion 20 that is connected or coupled to the robot main body 10 via the elastic connection portion 40 and the angle restricting joint portion 30 and constitutes the tip of the in-pipe moving robot 1. Therefore, for example, even when there is a step 2c (see FIG. 4) at the connection portion between the straight portion 2a and the bent portion 2b of the pipe 2, the tip main body portion 21 is moved along the bent portion 2b of the pipe 2 to make it difficult to catch on the step 2c, etc., and it is possible to suppress the tip main body portion 21 from getting caught on the bent portion 2b of the pipe 2.

[0055] More specifically, as shown in Fig. 5(a), when the tip main body portion 21 of the tip attitude maintaining portion 20 moves along the straight portion 2a of the tube 2, the pair of elastic bodies 22 and 23 contact the inner peripheral surface of the straight portion 2a of the tube 2 respectively, so that the tip main body portion 21 moves inside the tube 2 while maintaining the direction of its axis O parallel to the extending direction of the straight portion 2a of the tube 2. As shown in Fig. 5(b), when the tip attitude maintaining portion 20 advances and the tip main body portion 21 reaches the bent portion 2b from the straight portion 2a of the tube 2, the front elastic body 22 contacts the inner peripheral surface of the bent portion 2b of the tube 2 and the rear elastic body 23 contacts the inner peripheral surface of the straight portion 2a of the tube 2. Therefore, the tip main body portion 21 begins to bend along the bent portion 2b while rotating about the point 24a. At this time, the elastic connecting portion 40 elastically deforms so as to be compressed and bent between the tip main body portion 21 and the angle restricting joint portion 30, so that the rotation of the tip main body portion 21 with respect to the angle restricting joint portion 30 is allowed. As shown in Fig. 5(c), when the tip attitude maintaining portion 20 further advances and the rear elastic body 23 reaches the bent portion 2b, the tip attitude maintaining portion 20 has the pair of elastic bodies 22 and 23 contact the inner peripheral surface of the bent portion 2b of the tube 2 respectively. As shown in Fig. 5(d), the tip main body portion 21 moves inside the tube 2 along the bent portion 2b while rotating about the point 24a. As shown in Fig. 5(e), when the tip attitude maintaining portion 20 further advances and the front elastic body 22 passes through the bent portion 2b and reaches the straight portion 2a, the tip attitude maintaining portion 20 gradually returns to the attitude along the straight portion 2a because the front elastic body 22 contacts the inner peripheral surface of the straight portion 2a of the tube 2 and the rear elastic body 23 contacts the inner peripheral surface of the bent portion 2b of the tube 2. Then, as shown in Fig. 5(f), when the tip attitude maintaining portion 20 further advances and the rear elastic body 23 reaches the straight portion 2a, the pair of elastic bodies 22 and 23 contact the inner peripheral surface of the straight portion 2a of the tube 2 respectively, so that the tip attitude maintaining portion 20 moves inside the tube 2 while maintaining the direction of its axis O parallel to the extending direction of the straight portion 2a of the tube 2.

[0056] As described above, in the in-pipe moving robot 1 according to this embodiment, a pair of elastic bodies 22 and 23 arranged at an axial interval are provided on the tip main body portion 21 of the tip attitude maintaining portion 20 that is connected or coupled to the robot main body 10 via the elastic connection portion 40 and the angle restricting joint portion 30 to constitute the tip of the in-pipe moving robot 1. When the in-pipe moving robot 1 moves inside the pipe 2, the pair of elastic bodies 22 and 23 come into contact with the inner peripheral surface of the pipe 2 respectively, so that the tip main body portion 21 is guided in a posture along the pipe 2. Therefore, the tip main body portion 21 can smoothly pass through the bent portion 2b of the pipe 2. Further, in the in-pipe moving robot 1 according to this embodiment, as described above, the pair of elastic bodies 22 and 23 come into contact with the inner peripheral surface of the pipe 2 respectively, so that the tip main body portion 21 is guided in a posture along the pipe 2. Thus, it is possible to suppress the tip main body portion 21 from getting caught in the bent portion 2b of the pipe 2 and the elastic connection portion 40 from being elastically deformed to bend in the direction opposite to the bent portion 2b, causing the tip main body portion 21 to jam in the bent portion 2b of the pipe 2.

[0057] Moreover, in the in-pipe moving robot 1 according to this embodiment, when the pair of elastic bodies 22 and 23 are brushes, the tip main body portion 21 smoothly passes through the bent portion 2b of the pipe 2, so that the pair of elastic bodies 22 and 23 provided on the tip main body portion 21 can effectively clean both the outer peripheral side and the inner peripheral side inner surfaces of the bent portion 2b of the pipe 2. Further, when the configuration is such that the camera 25 is provided on the protruding portion 21b, the axis of the camera 25 can be stabilized in a certain direction, and the entire area of the object to be photographed inside the bent portion 2b of the pipe 2 can be photographed by the camera 25.

[0058] Furthermore, in the in-pipe moving robot 1 according to the present embodiment, since the tip main body portion 21 can smoothly pass through the bent portion 2b of the pipe 2, after the tip main body portion 21 is caught by the step 2c between the straight portion 2a and the bent portion 2b of the pipe 2 and the elastic connection portion 40 is compressed, the catching of the tip main body portion 21 by the step 2c is released, and it is possible to suppress the occurrence of an event in which the tip main body portion 21 moves inside the bent portion 2b vigorously by the spring force of the elastic connection portion 40. That is, the tip main body portion 21 can be smoothly passed through the bent portion 2b of the pipe 2 at a predetermined moving speed. As a result, when the pair of elastic bodies 22 and 23 are used as brushes, the inner surfaces on both the outer peripheral side and the inner peripheral side of the bent portion 2b of the pipe 2 can be more effectively cleaned by the pair of elastic bodies 22 and 23 provided on the tip main body portion 21. Further, when the camera 25 is provided on the protruding portion 21b, the inside of the bent portion 2b of the pipe 2 can be photographed by the camera 25 without skipping an image.

[0059] Furthermore, in the in-pipe moving robot 1 according to the present embodiment, since the protruding portion 21b protruding forward of the pair of elastic bodies 22 and 23 of the tip main body portion 21 is housed within the range of the virtual spherical surface 24 with which the outer peripheral ends of the pair of elastic bodies 22 and 23 are inscribed over the entire circumference, it is possible to make it more difficult for the tip main body portion 21 to be caught by the bent portion 2b or the step 2c of the pipe 2.

[0060] That is, as shown in FIG. 5, since the tip main body portion 21 rotates about the point 24a that becomes the center of the virtual spherical surface 24 when moving through the bent portion 2b of the pipe 2, by making the protruding portion 21b fit within the range of the virtual spherical surface 24, when the tip main body portion 21 moves through the bent portion 2b of the pipe 2, it is possible to make it difficult for the protruding portion 21 to contact the inner surface of the bent portion 2b of the pipe 2. As a result, it is possible to more effectively suppress the protruding portion 21 of the tip main body portion 21 from strongly contacting the inner surface of the bent portion 2b of the pipe 2 or being caught by the step 2c between the straight portion 2a and the bent portion 2b. Therefore, the tip main body portion 21 can pass through the bent portion 2b of the pipe 2 more smoothly.

[0061] Furthermore, in the in-pipe moving robot 1 according to the present embodiment, a protruding portion 21b that protrudes forward of the pair of elastic bodies 22 and 23 of the tip main body portion 21 is disposed within a range of a virtual spherical surface 24 that the outer peripheral ends 22a and 23a of the pair of elastic bodies 22 and 23 respectively inscribe over the entire circumference. Therefore, when the tip main body portion 21 moves through the bent portion 2b of the pipe 2, it is possible to prevent the protruding portion 21b from being rubbed against the inner surface of the bent portion 2b and getting damaged. As a result, when the camera 25 is provided inside the transparent protruding portion 21b, the inside of the pipe 2 can be photographed more clearly through the transparent protruding portion 21b by the camera 25.

[0062] In the in-pipe moving robot 1 according to the present embodiment, the rear elastic body 23 can be made more flexible than the front elastic body 22. That is, the rear elastic body 23 can be configured to be more easily elastically deformed in the axial direction with a smaller force than the front elastic body 22. As shown in FIGS. 5(c) and 5(d), when the tip main body portion 21 moves through the bent portion 2b of the pipe 2, the rear elastic body 23 may contact the inner surface on the inner circumferential side of the bent portion 2b more strongly than the front elastic body 22. However, by making the rear elastic body 23 more flexible than the front elastic body 22, it is possible to prevent the rear elastic body 23 from getting caught on the inner surface on the inner circumferential side of the bent portion 2b. In particular, when the bent portion 2b of the pipe 2 is an injection molded product made of resin, there may be protrusions such as burrs formed on the inner surface on the inner circumferential side of the bent portion 2b of the pipe 2. Even in such a case, by making the rear elastic body 23 more flexible than the front elastic body 22, it is possible to prevent the rear elastic body 23 from getting caught on the protrusions on the inner surface on the inner circumferential side of the bent portion 2b. Therefore, the tip main body portion 21 can pass through the bent portion 2b of the pipe 2 more smoothly.

[0063] Furthermore, in the in-pipe moving robot 1 according to the present embodiment, an angle restricting joint portion 30 is provided between the tip main body portion 21 and the robot main body 10 in addition to the elastic connection portion 40. Therefore, when the tip main body portion 21 passes through or after passing through the bent portion 2b of the pipe 2, it is possible to make it difficult for the front end of the robot main body 10 to be caught by the step 2c or protrusion of the bent portion 2b. That is, in the conventional one, even if the tip portion can pass through the step, there is a problem that the front end of the robot main body may be caught by the step next, and the in-pipe moving robot may not be able to move forward. However, in the in-pipe moving robot 1 according to the present embodiment, by having the angle restricting joint portion 30 in addition to the elastic connection portion 40 between the tip main body portion 21 and the robot main body 10, this problem can be suppressed.

[0064] More specifically, as shown in FIG. 6, after the tip main body portion 21 passes through the bent portion 2b of the pipe 2, in addition to the elastic connection portion 40 between the tip main body portion 21 and the robot main body 10, the angle restricting joint portion 30 bends along the bent portion 2b, so that the in-pipe moving robot 1 can smoothly move inside the bent portion 2b between the tip main body portion 21 and the robot main body 10. At this time, the angle restricting joint portion 30 is configured to restrict the bending angle of the tip main body portion 21 with respect to the robot main body 10 to an angle less than 90 degrees by the stopper portion 32 abutting against the front fixing portion 33. Therefore, it is possible to suppress the angle restricting joint portion 30 from bending to an excessive angle of 90 degrees or more and being in a buckled state inside the bent portion 2b. As a result, as shown in FIG. 7, after the tip main body portion 21 passes through the bent portion 2b, the angle restricting joint portion 30 can be pushed into the straight portion 2a without being caught by the step 2c. Therefore, after the tip main body portion 21 passes through the bent portion 2b, the angle restricting joint portion 30 and the robot main body 10 can also smoothly pass through the bent portion 2b.

[0065] Next, based on FIGS. 8, 9, and 10, the in-pipe moving robot 100 according to the second embodiment of the present invention will be described. In FIGS. 8, 9, and 10, members or parts corresponding to the members or parts described above are given the same reference numerals. Also, in the in-pipe moving robot 100 according to the second embodiment, the configurations of the robot body 10, the tip attitude maintaining unit 20, the angle regulating joint unit 30, and the elastic connection unit 40 are basically the same as those of the robot body 10, the tip attitude maintaining unit 20, the angle regulating joint unit 30, and the elastic connection unit 40 of the in-pipe moving robot 1 of the first embodiment, so the description will be omitted again.

[0066] As shown in FIG. 8, the in-pipe moving robot 100 according to the second embodiment is different from the in-pipe moving robot 1 according to the first embodiment in that it has a cover 50 that covers the angle regulating joint unit 30.

[0067] As shown in FIG. 9, the cover 50 has a double structure including an inner cylindrical body 51 and an outer cylindrical body 52. The inner cylindrical body 51 is formed in a cylindrical shape centered on the axis O from a stretchable material and is arranged coaxially with the angle regulating joint unit 30 to cover the entire outside of the angle regulating joint unit 30. The outer cylindrical body 52 is formed in a cylindrical shape with a larger diameter than the inner cylindrical body 51 and coaxially with the inner cylindrical body 51 from a stretchable material, and is arranged to overlap the outside of the inner cylindrical body 51 to cover the entire outside of the inner cylindrical body 51. The outer cylindrical body 52 may be arranged to contact the inner cylindrical body 51, or may be arranged to have a gap between it and the inner cylindrical body 51. The cover 50 is fixed to the angle regulating joint unit 30 using pressing members 53, 54 at the folded-back portions of both ends of the inner cylindrical body 51 and the outer cylindrical body 52. Inclined surfaces 53a, 54a are provided between the outer peripheral surface and the side surface of the pressing members 53, 54.

[0068] Note that the configuration for fixing the cover 50 to the angle regulating joint unit 30 can be appropriately changed, such as directly fixing the ends of the inner cylindrical body 51 and the outer cylindrical body 52 to the front fixing portion 33 and the rear fixing portion 34 using a binding band.

[0069] In this embodiment, the inner cylindrical body 51 and the outer cylindrical body 52 are each composed of a cloth (fabric) woven with nylon fibers in a predetermined pattern, and are each stretchable in the axial direction and in the radial direction centered on the axis O. Since the inner cylindrical body 51 and the outer cylindrical body 52 are each composed of a nylon fabric with relatively low frictional resistance, the frictional resistance generated between the inner cylindrical body 51 and the outer cylindrical body 52 is smaller than the frictional resistance generated between the inner cylindrical body 51 and the angle regulating joint portion 30 and the frictional resistance generated between the outer cylindrical body 52 and the inner surface of the pipe 2. Thus, the cover 50 is configured such that the frictional resistance generated between the inner cylindrical body 51 and the outer cylindrical body 52 is smaller than the frictional resistance generated between the outer cylindrical body 52 and the inner surface of the pipe 2. Note that the cover 50 is not limited to a cloth woven with nylon fibers in a predetermined pattern, and may be composed of other cloth or sheet-like materials as long as it is configured such that the frictional resistance generated between the inner cylindrical body 51 and the outer cylindrical body 52 is smaller than the frictional resistance generated between the outer cylindrical body 52 and the inner surface of the pipe 2.

[0070] As shown in FIG. 10, when the in-pipe moving robot 100 according to the second embodiment passes through the bent portion 2b of the pipe 2, the angle regulating joint portion 30 advances in a bent state, and thus the cover 50 covering the angle regulating joint portion 30 is strongly pressed against the inner surface on the outer peripheral side of the pipe 2. At this time, since the cover 50 has a double structure including the inner cylindrical body 51 and the outer cylindrical body 52, even if the outer cylindrical body 52 is strongly pressed against the inner surface on the outer peripheral side of the pipe 2 and cannot slide forward on the inner surface of the pipe 2 due to the frictional resistance therebetween, as the outer cylindrical body 52 extends in the axial direction and the inner cylindrical body 51 pressed against the outer cylindrical body 52 by the angle regulating joint portion 30 slides relative to the outer cylindrical body 52, the angle regulating joint portion 30 can slightly advance inside the pipe 2. Then, by the driving force due to this slight advancement, the outer cylindrical body 52 is caused to slide in the forward direction relative to the inner surface of the pipe 2, and the in-pipe moving robot 100 can be advanced inside the pipe 2.

[0071] As described above, in the in-pipe moving robot 100 according to the second embodiment, since it is configured to have the cover 50 that covers the angle regulating joint portion 30, even when the angle regulating joint portion 30 is strongly pressed against the inside of the pipe 2 when the in-pipe moving robot 100 passes through the bent portion 2b of the pipe 2, the in-pipe moving robot 100 can be surely advanced.

[0072] Further, since the inclined surface 53a is provided on the front pressing member 53 for fixing the cover 50, the pressing member 53 can overcome the step 2c at the inclined surface 53a, and the in-pipe moving robot 100 can be advanced more surely.

[0073] Next, based on FIGS. 11 and 12, the in-pipe moving robot 200 according to the third embodiment of the present invention will be described. In FIGS. 10 and 11, the members or portions corresponding to the members or portions described above are denoted by the same reference numerals. In the in-pipe moving robot 200 according to the third embodiment, the configurations of the robot body 10, the tip attitude maintaining portion 20, and the elastic connection portion 40 are basically the same as those of the robot body 10, the tip attitude maintaining portion 20, and the elastic connection portion 40 of the in-pipe moving robot 1 according to the first embodiment, and thus the description thereof will be omitted.

[0074] As shown in FIG. 11, the in-pipe moving robot 200 according to the third embodiment is different from the in-pipe moving robot 1 according to the first embodiment in that the angle regulating joint portion 30 has a stopper position changing device 60 that changes the axial position of the stopper portion 32.

[0075] In this embodiment, the stopper position changing device 60 includes an air cylinder 61 and a connecting body 62 fixed to the rod 61a of the air cylinder 61. The connecting body 62 is connected to the stopper portion 32, and the stopper portion 32 is configured to move integrally with the connecting body 62. The stopper position changing device 60 can stepwise change the position of the stopper portion 32 by the operation of the air cylinder 61 to a position closer to the front fixing portion 33 shown in Fig. 12(a), a position farther from the front fixing portion 33 than the position closest to the front fixing portion 33 shown in Fig. 12(b), and a position farthest from the front fixing portion 33 shown in Fig. 12(c). Thus, by changing the position of the stopper portion 32 by the stopper position changing device 60, the distance between the stopper portion 32 and the front fixing portion 33 can be changed, and the bending angle of the angle restricting joint portion 30 can be changed to a plurality of angles less than 90 degrees according to the shape of the bent portion 2b of the pipe 2.

[0076] Note that the position of the stopper portion 32 changed by the stopper position changing device 60 is not limited to the above three positions and can be set as appropriate.

[0077] The stopper position changing device 60 can determine, in a control device (not shown), the bending angle of the bent portion 2b based on the captured image inside the pipe 2 captured by the camera 25, and automatically control the operation of the air cylinder 61 by the control device so that the stopper portion 32 is at a position corresponding to the bent portion 2b of the pipe 2.

[0078] Alternatively, the stopper position changing device 60 may be configured to manually operate the connecting body 62 so that the stopper portion 32 is at a position corresponding to the bent portion 2b of the pipe 2 without using the air cylinder 61. In this case, the connecting body 62 may be manually operated before inserting the in-pipe moving robot 1 into the pipe 2.

[0079] Next, based on FIGS. 13 and 14, the in-duct mobile robot 300 according to the fourth embodiment of the present invention will be described. In FIGS. 13 and 14, members or portions corresponding to the members or portions described above are denoted by the same reference numerals. Further, in the in-duct mobile robot 300 according to the fourth embodiment, the configurations of the robot body 10, the angle restricting joint portion 30, and the elastic connection portion 40 are basically the same as those of the robot body 10, the angle restricting joint portion 30, and the elastic connection portion 40 of the in-duct mobile robot 1 according to the first embodiment. Therefore, repeated description will be omitted.

[0080] As shown in FIG. 13, the in-duct mobile robot 300 according to the fourth embodiment is different from the in-duct mobile robot 1 according to the first embodiment in that the tip attitude maintaining portion 20 has an intermediate elastic body 27 between the front elastic body 22 and the rear elastic body 23 in addition to the front elastic body 22 and the rear elastic body 23 on the front side. More specifically, in the in-duct mobile robot 300 according to the fourth embodiment, the front elastic body 22 is disposed at the front end of the tip main body portion 21, the rear elastic body 23 is disposed at the rear end of the tip main body portion 21, and an intermediate elastic body 27 is disposed between the front elastic body 22 and the rear elastic body 23 with a space from both the front elastic body 22 and the rear elastic body 23. The outer diameter of the intermediate elastic body 27 is the same as those of the elastic bodies 22 and 23.

[0081] In the in-pipe moving robot 300 according to the fourth embodiment, as shown in FIG. 14(a), when the tip main body portion 21 of the tip attitude maintaining portion 20 moves along the straight portion 2a of the pipe 2, the pair of elastic bodies 22, 23 and the elastic body 27 are respectively in contact with the inner peripheral surface of the straight portion 2a of the pipe 2, so that the tip main body portion 21 moves inside the pipe 2 while maintaining the direction of its axis O parallel to the extending direction of the straight portion 2a of the pipe 2. As shown in FIG. 14(b), when the tip attitude maintaining portion 20 advances and the tip main body portion 21 reaches the bent portion 2b from the straight portion 2a of the pipe 2, the front elastic body 22 contacts the inner peripheral surface of the bent portion 2b of the pipe 2, and the tip main body portion 21 starts to bend along the bent portion 2b while rotating about the point 24a. Then, as shown in FIGS. 14(c) and 14(d), when the tip attitude maintaining portion 20 further advances, the intermediate elastic body 27 catches on the inner surface on the inner peripheral side of the bent portion 2b of the pipe 2, and the rotation of the tip main body portion 21 about the point 24a is promoted. As shown in FIG. 14(e), when the tip attitude maintaining portion 20 further advances and the front elastic body 22 passes through the bent portion 2b and reaches the straight portion 2a, the catching of the intermediate elastic body 27 on the inner surface on the inner peripheral side of the bent portion 2b is released, and the tip attitude maintaining portion 20 gradually returns to the attitude along the straight portion 2a when the front elastic body 22 contacts the inner peripheral surface of the straight portion 2a of the pipe 2 and the rear elastic body 23 contacts the inner peripheral surface of the bent portion 2b of the pipe 2. Then, as shown in FIG. 14(f), when the tip attitude maintaining portion 20 further advances and the rear elastic body 23 reaches the straight portion 2a, the pair of elastic bodies 22, 23 and the elastic body 27 are respectively in contact with the inner peripheral surface of the straight portion 2a of the pipe 2, and the tip attitude maintaining portion 20 moves inside the pipe 2 while maintaining the direction of its axis O parallel to the extending direction of the straight portion 2a of the pipe 2.

[0082] Thus, in the in-pipe moving robot 300 according to the fourth embodiment, the tip attitude maintaining portion 20 is configured to have an intermediate elastic body 27 between the front elastic body 22 and the rear elastic body 23 in addition to the front elastic body 22 and the rear elastic body 23, so that the tip attitude maintaining portion 20 can pass through the bent portion 2b more smoothly. As a result, the in-pipe moving robot 300 can more reliably pass through the bent portion 2b of the pipe 2.

[0083] In the in-pipe moving robot 300 according to the fourth embodiment, while the front elastic body 22 and the rear elastic body 23 are made to have the same hardness or flexibility as each other, it is preferable that the intermediate elastic body 27 is configured to elastically deform more flexibly than the front elastic body 22 and the rear elastic body 23. Thereby, as shown in FIGS. 14(c) and 14(d), when the intermediate elastic body 27 is caught on the inner surface on the inner circumferential side of the bent portion 2b of the pipe 2, the rotation about the point 24a of the tip main body portion 21 is promoted while the intermediate elastic body 27 can surely pass through the bent portion 2b, so that the in-pipe moving robot 300 can more surely pass through the bent portion 2b.

[0084] Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

[0085] For example, in the first embodiment, the tip main body portion 21 of the tip attitude maintaining portion 20 is configured to have the protruding portion 21b, but the tip main body portion 21 may not be provided.

Explanation of Reference Numerals

[0086] 1 In-pipe moving robot 2 Pipe 2a Straight portion 2b Bent portion 2c Step 10 Robot main body 11 Telescopic unit 12 Connecting portion 13 Pipe 14 Control unit 15 Brush 20 Tip attitude maintaining portion 21 Tip main body portion 21a Trunk portion 21b Protruding portion 22 Elastic body 23 Elastic body 24 Virtual spherical surface 24a Point 25 Camera 26 Lighting device 27 Elastomer 30 Angle-regulating joint part 31 Universal joint part 32 Stopper part 33 Front fixing part 34 Rear fixing part 35 Front rotation axis 36 Rear rotation axis 40 Elastic connection part 50 Cover 51 Inner cylindrical body 52 Outer cylindrical body 53 Pressing member 53a Inclined surface 54 Pressing member 54a Inclined surface 60 Stopper position changing device 61 Air cylinder 61a Rod 62 Connecting body 100 In-pipe moving robot 200 In-pipe moving robot 300 In-pipe moving robot O Axis

Claims

1. An in-pipe mobile robot comprising a robot body having at least three telescopic units each of which expands in a radial direction and contracts in an axial direction when a fluid is supplied thereto, the telescopic units moving in a predetermined pattern by peristaltic motion to move inside the pipe, a tip body portion constituting the tip of the intra-pipe mobile robot; and a tip attitude maintaining unit having a pair of elastic bodies each of which is roughly circular around the axis of the tip body portion or annular with an outer periphery having a regular polygonal shape, protruding radially outward from an outer periphery of the tip body portion and disposed at a distance from each other in the axial direction; an elastically deformable elastic connection portion provided between the tip attitude maintaining portion and the robot main body; and an angle control joint portion provided between the elastic connection portion and the robot body, which enables the tip attitude maintenance portion to be bent at an angle of less than 90 degrees relative to the robot body.

2. An in-pipe mobile robot comprising a robot body having at least three telescopic units each of which expands in a radial direction and contracts in an axial direction when a fluid is supplied thereto, the telescopic units moving in a predetermined pattern by peristaltic motion to move inside the pipe, a tip body portion constituting the tip of the intra-pipe mobile robot; and a tip attitude maintaining unit having a pair of elastic bodies each of which is roughly circular around the axis of the tip body portion or annular with an outer periphery having a regular polygonal shape, protruding radially outward from an outer periphery of the tip body portion and disposed at a distance from each other in the axial direction; an elastic connection part that is elastically deformable and is provided between the tip attitude maintaining part and the robot main body, an inner-pipe mobile robot, characterized in that a protruding portion of the tip main body portion that protrudes forward beyond the pair of elastic bodies is contained within the range of an imaginary spherical surface inscribed over the entire circumference of each of the outer peripheral ends of the pair of elastic bodies.

3. An in-pipe mobile robot comprising a robot body having at least three telescopic units each of which expands in a radial direction and contracts in an axial direction when a fluid is supplied thereto, the telescopic units moving in a predetermined pattern by peristaltic motion to move inside the pipe, a tip body portion constituting the tip of the intra-pipe mobile robot; and a tip attitude maintaining unit having a pair of elastic bodies each of which is roughly circular around the axis of the tip body portion or annular with an outer periphery having a regular polygonal shape, protruding radially outward from an outer periphery of the tip body portion and disposed at a distance from each other in the axial direction; an elastic connection part that is elastically deformable and is provided between the tip attitude maintaining part and the robot main body, 13. An intra-pipe mobile robot, wherein the elastic body on the rear side is softer than the elastic body on the front side.

4. 4. The intra-pipe mobile robot according to claim 1, further comprising a camera provided on the axis of a protruding portion of the tip main body that protrudes forward beyond the pair of elastic bodies.

5. 2. The intra-pipe mobile robot according to claim 1, comprising an inner cylindrical body formed into a cylindrical shape having elasticity, and an outer cylindrical body formed into a cylindrical shape having elasticity and arranged on the outside of the inner cylindrical body, and having a cover configured so that the frictional resistance generated between the inner cylindrical body and the outer cylindrical body is smaller than the frictional resistance generated between the outer cylindrical body and the inner surface of the pipe, and the cover covers the angle restricting joint portion.

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