JPH08216876A - In-pipe traveling device - Google Patents

Abstract

PURPOSE: To provide an in-pipe traveling device that is travelable in a state that the whole device keeps a stable attitude in a pipeline as in stableness. CONSTITUTION: This device is provided with an inertial body 1 and two piezoelectric elements 21 and 2b being connected to this inertial body and expansibly deformed by way of the impression and release of voltage. In this in-pipe traveling device, traveling by means of inertly driving the inertial body 1 with these piezoelectric elements 2a and 2b, each two of pins 4a, 4b and 4c, 4d in contact with a pipe wall each is installed in both ends in front and in the rear of the device, and these two by two pins 4a, 4b and 4c, 4d are symmetrically installed with one another to the center shaft. Since two by two pins are installed in both front and rear ends at the symmetrical position, these pins come to contact with the inner surface of a diametral part of a pipeline, whereby this device can be kept in a stable attitude, and thus even in the case of movements, this device can be kept in the stable attitude.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-pipe moving device capable of self-propelling inside an industrial pipe or a living body pipe by utilizing inertial force.

[0002]

2. Description of the Related Art Recently, as a device for inspecting a flaw in a pipe having an inner diameter of several mm, which is used in a nuclear power plant or the like,
Micro inspection machines have been developed. This type of microinspection machine has an outer diameter of several mm and is formed in a size that allows it to move freely in the pipe, and has a sensor for inspecting the inside of the pipe at the tip, and a drive unit after that. There is. The drive unit is configured by connecting a piezoelectric element that expands and contracts by applying and releasing a voltage to the inertial body, for example, a laminated piezoelectric body, and moves in a path using the inertia of the inertial body due to the expansion and contraction of the piezoelectric element. It is like this.

That is, a passage-type tube moving device utilizing such inertial force is disclosed in Japanese Patent Laid-Open No. 4-176770, and when the drive voltage applied to the piezoelectric element is controlled, the piezoelectric element expands and contracts. However, by restricting either one of the expansion and contraction movements by the inertia of the inertial body, the entire apparatus is moved, and such movement is repeated so that the tube itself travels.

[0004]

However, in the conventional in-pipe moving device disclosed in the above publication, a moving body that receives the frictional force in the pipe is provided at one end of the piezoelectric element that expands and contracts, and the other end is moved from the moving body. An inertial body with a small mass is provided,
The entire moving device has a structure supported by the moving body. Therefore, the entire device has a structure with one end support,
Since the self-standing is unstable and the contact area of the moving body with the pipe wall is large, there is a problem that the movement is unstable due to the influence of the surface of the pipe wall.

Further, when the passage of the pipe is bent, it is difficult to smoothly change the tip of the moving device in the bending direction. The present invention has been made in view of the above circumstances, and an object thereof is to provide an in-pipe moving device capable of moving in a stable state with the entire device maintaining a stable posture in the pipe. is there.

[0006]

According to a first aspect of the present invention, there is provided an inertial body and a piezoelectric element which is connected to the inertial body and expands and contracts by applying and releasing a voltage. In an intra-tube moving device that moves by inertial drive, two front and rear end portions of the device are provided with two legs each in contact with a pipe wall, and these two legs are provided symmetrically with respect to a central axis. The in-pipe moving device is characterized in that

According to the second aspect of the invention, the total of four legs in front and rear are
The in-pipe moving device according to claim 1, wherein the in-pipe moving device is provided on a plane passing through the central axis. The invention of claim 3 is the in-pipe moving device according to claim 1, wherein the front foot and the rear foot are provided so as to be rotatable relative to each other about the central axis.

The invention according to claim 4 is characterized in that a piezoelectric element, which operates so that when one extends, the other contracts, is connected to both ends of the inertial body, respectively. It is the in-pipe moving device described.

[0009]

According to the first aspect of the present invention, since two feet are provided at each of the front and rear ends of the apparatus at symmetrical positions, the feet come into contact with the inner surface of the diameter portion of the pipe. Therefore, the posture of the device can be maintained in a stable state in the pipe, and the device can be kept in a stable posture even when moving forward or backward.

According to the invention of claim 2, since a total of four front and rear legs are provided on a plane passing through the central axis, the device as a whole rotates to a posture with little resistance when passing through the bending conduit. Instead, it can smoothly pass through the bent portion.

According to the third aspect of the present invention, the front foot and the rear foot out of a total of four front and rear feet are provided so as to be rotatable relative to each other around the central axis, and therefore, pass through the bending conduit. Sometimes, the front foot or the rear foot rotates independently to change into a posture with less resistance, and it is possible to smoothly pass through the bent portion.

According to the fourth aspect of the present invention, piezoelectric elements that act so that when one extends the other contracts are connected to both ends of the inertial body, the path length in one cycle is large, and therefore the moving speed is high. It is possible to eliminate the difference in operation between the case of moving forward and the case of moving backward as soon as possible.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the first embodiment shown in FIGS. FIG. 1 is a half sectional side view showing the entire structure of the in-pipe moving device. In FIG. 1, reference numeral 1 is a weight as an inertial body. The weight 1 is made of a metal having a high specific gravity, such as lead, and actuators capable of abrupt expansion and contraction, that is, piezoelectric elements 2a and 2b that expand and contract when a voltage is applied, are joined to both ends in the front-rear direction. ing. As the piezoelectric elements 2a and 2b of this example, a piezoelectric body (PZT) having a laminated structure composed of several tens of layers is used. These laminated piezoelectric bodies 2
Since a and 2b transmit a sudden expansion and contraction operation to the weight 1 without attenuating, they are firmly bonded or joined.

The weight 1 and the laminated piezoelectric bodies 2a and 2b
Are covered by a shell 3 for protection against disturbances in the pipe. The shell 3 has a bellows-shaped cylindrical shape made of metal in order to secure a heat radiation area and has rigidity. The shell 3 may be expanded / contracted but may not be expanded / contracted. Both ends of the shell 3 have the above-mentioned laminated piezoelectric body 2
The weights 1 of a and 2b are firmly bonded or joined to the front end portion and the rear end portion which are not joined.

Incidentally, the shell 3 and the laminated piezoelectric bodies 2a, 2b
Is arranged so as to prevent short-circuiting between the shell 3 and the electrodes (not shown) of the laminated piezoelectric bodies 2a and 2b, so that the shell 3 and the weight 1 are not in contact with each other except for the bonding portions of these ends. They are arranged so as not to contact (interfere) with each other in order to prevent frictional resistance between them.

Two feet 4a, 4b and 4c, 4d are attached to the front and rear ends of the shell 3, respectively. These feet 4a, 4b and 4c, 4d
Are formed of thin wires made of metal such as SUS, and extend in the front oblique direction and the rear oblique direction, respectively, so that the tip ends contact the inner surface of the pipe wall.

These feet 4a, 4b and 4c, 4d are
The two front legs 4a and 4b are arranged symmetrically with respect to the center line passing through the weight 1 and the laminated piezoelectric bodies 2a and 2b, and the two rear legs 4c and 4d are also the above center lines. They are arranged symmetrically with respect to. In this embodiment,
A total of four legs 4a, 4b and 4c, 4d are on the diameter of the device when viewed from the front of the device, as shown in FIG. 2, ie four legs 4a, 4b and 4c, 4d are piped. The points contacting the inner surface are formed on the same plane passing through the center line.

The laminated piezoelectric bodies 2a and 2b are connected to an arbitrary waveform generator 7 via a wiring 5 and an amplifier 6, respectively. The arbitrary waveform generator 7 can arbitrarily change and set the voltage of the power source 8 to a sawtooth voltage waveform of several kHz as shown in FIG. 3 or FIG.
The voltage waveform selected at is 0 to 100 at the amplifier 6.
It is amplified to V and applied to the laminated piezoelectric bodies 2a and 2b via the wiring 5.

The operation of the in-pipe moving device configured as described above will be described. FIG. 4 shows a case where the in-pipe moving device moves inside the pipe 10 from left to right in the drawing. The arbitrary waveform generator 7 generates a voltage having a sawtooth waveform of several kHz which rises gently and is instantly returned to 0 or negative as shown in FIG. It is amplified and applied to the laminated piezoelectric bodies 2a and 2b.
At this time, a negative rising voltage is applied to the front laminated piezoelectric body 2a, and a positive rising voltage is applied to the rear laminated piezoelectric body 2b. Then, as shown in FIGS. 4A to 4C, the front laminated piezoelectric body 2a contracts slowly and the rear laminated piezoelectric body 2b slowly extends. In this case, the distance L between the front legs 4a, 4b and the rear legs 4c, 4d does not change, and therefore the length of the shell 3 does not change, so that only the weight 1 moves to the right.

FIG. 4 (B) shows a state in which the weight 1 is being moved to the right, and the dimension a from the initial position shown in FIG. 4 (A).
(4-C) shows the state in which the weight 1 has moved to the far right, and is the state in which the weight b has moved further from the position shown in (4-B). Therefore,
The state shown in (4-C) shows a state in which the weight 1 has moved by a dimension a + b from the initial position shown in (4-A).

After such movement of the weight 1, the applied voltage is suddenly returned to the original value. Then, the contracted front laminated piezoelectric body 2a
Abruptly expands to the original length, and the expanded laminated piezoelectric body 2b at the rear part abruptly contracts to the original length. At this time, the inertial force (resting force) of the weight 1 is applied to each foot 4a, 4b and 4c, 4d.
The weight 1 does not move and the distance L between the front legs 4a and 4b and the rear legs 4c and 4d does not change because the static friction force between the inner surface of the pipe 10 and the inner surface of the pipe 10 is not changed. Since this does not change, the legs 4a, 4b and 4c, 4d slide on the inner surface of the pipe 10 and the entire apparatus advances as shown in (4-D) of FIG.

In this case, the legs 4a, 4b and 4
Since there is some frictional resistance between c and 4d and the inner surface of the pipe 10, the weight 1 returns by a minute amount δ. Therefore, as described above, when one cycle of the voltage having a sawtooth waveform that gradually rises and is instantly restored is applied, the entire apparatus moves forward by a distance corresponding to the dimension X = a + b-δ. . After that, if the sawtooth waveform voltage is applied for a plurality of cycles, the operation is returned according to the number of cycles, and thus the in-pipe moving device passes through the pipe 10 from left to right sequentially.

On the contrary, when moving the inside of the pipe 10 from the right side to the left side of the drawing by the in-pipe moving device of the first embodiment, the positive and negative of the voltage applied to the laminated piezoelectric bodies 2a and 2b are changed. Reverse. That is, although not shown, a positive and slow rising voltage is applied to the front laminated piezoelectric body 2a,
In addition, a negative slow rising voltage is applied to the rear laminated piezoelectric material 2b. Then, contrary to the case shown in FIGS. 4 (A) to 4 (C), the laminated piezoelectric body 2a in the front portion is reversed.
Is slowly extended and the laminated piezoelectric body 2b at the rear portion is slowly contracted, whereby the weight 1 moves to the left.

When the applied voltage is suddenly returned to the original value after the movement of the weight 1, the stretched front laminated piezoelectric material 2a is rapidly contracted to the original length, and the contracted rear laminated piezoelectric material 2b is contracted. Rapidly expands to the original length, and at this time, due to the inertial force (resting force) of the weight 1, the legs 4a, 4b and 4c, 4d are connected to the pipe 10
It slides on the inner surface of and moves to the left. Therefore, in this case, the pipe moving device passes through the pipe 10 from right to left.

If the structure of the front laminated piezoelectric body 2a and the rear laminated piezoelectric body 2b are made the same, the path length when the in-tube moving device moves to the right side and the path length when moving to the left side. It is possible to make the distances the same, and it is possible to eliminate the difference between the forward and backward movements.

In the in-tube moving device having the above-mentioned configuration, the arbitrary waveform generator 7 selects another voltage waveform different from that shown in FIG. 3 and applies the voltage waveform to the laminated piezoelectric bodies 2a and 2b to move it forward and backward by another operation. You can also That is, FIG.
Shows a voltage waveform of a sawtooth waveform generated by the arbitrary waveform generator 7 that instantly rises and is gradually returned to 0 or negative. FIG. 6 uses this voltage waveform to move the in-pipe moving device forward. It is explanatory drawing which shows the case where it is made.

That is, the sawtooth voltage of FIG. 5 generated by the arbitrary waveform generator 7 is amplified by the amplifier 6, and the laminated piezoelectric material 2 is obtained.
It is applied to a and 2b. At this time, the laminated piezoelectric body 2a in the front part
A positive abrupt rising voltage is applied to, and a negative abrupt rising voltage is applied to the rear laminated piezoelectric material 2b.
Then, as shown in FIGS. 6-A to 6-B, the front laminated piezoelectric body 2a expands rapidly and the rear laminated piezoelectric body 2b contracts rapidly.

At this time, the inertial force (static force) of the weight 1 is
The weight 1 does not move because it is set to be larger than the static frictional force between each foot 4a, 4b and 4c, 4d and the inner surface of the pipe 10, and the front feet 4a, 4b and the rear feet 4c, 4d.
Since the distance L does not change and the length of the shell 3 does not change, the legs 4a, 4b and 4c, 4d slide on the inner surface of the pipe 10 and the entire apparatus is moved as shown in Fig. 6-B. Move forward (forward distance X).

After that, the voltages applied to the laminated piezoelectric bodies 2a and 2b are slowly returned. Then, the front laminated piezoelectric body 2a contracts slowly, and the rear laminated piezoelectric body 2b slowly expands. In this case, the front legs 4a, 4b and the rear legs 4
Since the distance L of c and 4d does not change and therefore the length of the shell 3 does not change, only the weight 1 moves to the right as shown in FIGS. 6-C and 6-D.

FIG. 6-C shows a state in which the weight 1 is moving to the right side, when the weight 1 is moved from the position shown in FIG. 6-B by the dimension a, and FIG. 6-D shows the weight. 1 shows a state when 1 is moved to the neutral position, and is a state in which it is further moved by the dimension b from the position shown in (6-C). Therefore,
The state shown in (6-D) shows a state in which the weight 1 has moved by a dimension a + b from the initial position shown in (6-A).
The in-pipe moving device moves forward a distance corresponding to X = a + b.

Such a passage is repeated for each cycle, and the pipe moving device sequentially advances the pipe 10 from left to right according to the number of cycles. On the contrary, when the in-pipe moving device is moved from the right side to the left side of the pipe 10, the positive and negative voltages applied to the laminated piezoelectric bodies 2a and 2b shown in FIG. A negative abrupt rising voltage is applied to the laminated piezoelectric body 2a, and a positive abrupt rising voltage is applied to the rear laminated piezoelectric body 2b. Then, contrary to the case shown in FIGS. 6-A and 6-B, the front laminated piezoelectric body 2a contracts sharply and the rear laminated piezoelectric body 2b rapidly expands, whereby the weight is reduced. 1 moves to the left. At this time, the weight 1 is moved by the inertial force (static force) of the weight 1.
Does not move, each leg 4a, 4b and 4c, 4d and the pipe 10
The inner surface of the device slides and the entire device moves backward in the direction opposite to that in (6-B).

After that, when the applied voltage is slowly returned to the original value, the contracted front laminated piezoelectric material 2a slowly expands to the original length and the expanded rear laminated piezoelectric material 2b.
Contracts slowly to its original length, and therefore the weight 1 moves to the neutral position between the front laminated piezoelectric body 2a and the rear laminated piezoelectric body 2b.

By repeating such an operation, the pipe moving device can move from the right side to the left side of the pipe 10. In this case also, since the front laminated piezoelectric body 2a and the rear laminated piezoelectric body 2b have the same structure, the path length when the in-tube moving device moves to the right side and the path length when moving to the left side. It is possible to make the distances the same, and it is possible to eliminate the difference between the forward and backward movements.

Further, the in-pipe moving device having the above-mentioned structure can smoothly proceed while changing the traveling direction by itself when advancing along a curved pipe path. That is, FIG. 7 shows the operation in the case of traveling along the curved conduit 12. (7-A) is a state in which the plane including the contact points between the four legs 4a, 4b and 4c, 4d of the intra-tube moving device and the tube wall is flush with the bending direction of the bending conduit 12. In this case, when the in-pipe moving device reaches the bent portion of the duct 12 in this state, the frictional resistance between one of the front legs 2a or 2b and the bent pipe wall increases. If the forward movement is continued as it is, the in-pipe moving device rotates to the right or the left (rotates) as shown in (7-B) in an attempt to reduce the resistance applied to one of the front legs 2a or 2b.
Will be done.

As a result, the in-pipe moving device spirally rotates in the bending conduit 12, and the four legs 4a, 4b and 4c, 4d come into contact with the pipe wall as shown in FIG. 7C. The plane including the points is in a posture perpendicular to the bending direction of the bending conduit 12,
As a result, the posture is such that there is little frictional resistance, and the robot moves forward in this state.

This is the above-mentioned four legs 4a, 4b and 4
This is possible because c and 4d are arranged in the same plane. Therefore, with such a configuration, it is possible to smoothly proceed while changing the direction of the bent conduit 12 by itself.

For this reason, if a flaw detection sensor (not shown) is attached to the above-mentioned in-pipe moving device, the flaw detection sensor can be moved forward or backward in the pipe in accordance with the forward or backward movement of the in-pipe moving device. It is possible to inspect the inner surface of the pipe for scratches. Moreover, the laminated piezoelectric body 2
A and 2b can be made small, and a micro inspection machine having an outer diameter of 6 mm and a length of about 20 mm can be manufactured.

FIG. 8 and FIG. 9 are views of a pipe moving device showing a second embodiment of the present invention. In this example,
Radiating fins 6a and 6b are attached to the front laminated piezoelectric body 2a and the rear laminated piezoelectric body 2b, respectively. Generally, the laminated piezoelectric material has a property of generating heat by the expansion and contraction action by applying and releasing a voltage. Therefore, the radiation fins 2 are provided at the end portions of the front laminated piezoelectric material 2a and the rear laminated piezoelectric material 2b, respectively.
0a and 20b are attached, these radiation fins 2
Since the heat is radiated by the heat radiating action of 0a and 20b, the temperature rise of the laminated piezoelectric material can be suppressed, and the life characteristics are improved.

10 and 11 show a third embodiment of the present invention. This in-pipe moving device is an example in which at least one of the front legs 4a, 4b and the rear legs 4c, 4d is rotatably attached to the shell 3 by the support shafts 30, 30. With this configuration, when the frictional resistance is applied to one of the front legs 4a and 4b at the bending portion when advancing along the bending duct 12 as shown in FIG. 7, the entire intra-tube moving device rotates spirally (rotates). Without doing so, only the front legs 4a, 4b rotate and take a vertical posture with respect to the plane including the bending direction, and the bending portion can be smoothly advanced. In addition, hind legs 4c and 4d
Even when the human body approaches the bent portion, only the rear legs 4c and 4d rotate to be in a posture with less friction.

FIG. 12 shows a fourth embodiment of the present invention. In this embodiment, the piezoelectric element, that is, the laminated piezoelectric body 2 is bonded to only one end of the weight 1. That is, in the first to third embodiments, the in-tube moving device having the structure in which the laminated piezoelectric bodies 2a and 2b are joined to the front and rear of the weight 1 has been described, but the fourth embodiment shown in FIG. 1 has a structure in which the laminated piezoelectric body 2 is joined to one end of the laminated body 1. One end of a shell 3 is joined to the end of the laminated piezoelectric body 2, and the other end of the shell 3 is separated from the weight 1. Two front legs 4a and 4b are attached to the front end of the shell 3, and two rear legs 4c and 4d are attached to the rear end of the shell 3.

Even in the case of such a structure, the laminated piezoelectric material 2
Is contracted or extended rapidly, the inertial force of the weight 1 does not move the weight 1 but the shell 3 moves forward or backward,
When the above-mentioned laminated piezoelectric body 2 slowly expands or contracts, the shell 3 does not move due to the friction between the legs 4a, 4b and 4c, 4d and the tube wall, and the weight 1 moves. Therefore, it is possible to go forward or backward. Although the shell 3 is used in the first to third embodiments, the shell 3 is used in these embodiments.
May be omitted.

[0042]

As described above, according to the first aspect of the present invention, two feet provided at each of the front and rear ends of the device come into contact with the inner surface of the diameter portion of the pipe, so that the posture of the device is maintained. The stable state can be maintained in the pipe, and the device can be maintained in a stable posture even when moving forward or backward.

According to the second aspect of the invention, since the total of four legs are provided on the plane passing through the central axis, the entire device rotates to change to a posture with less resistance when passing through the bending conduit, It can smoothly pass through the bent portion.

According to the third aspect of the present invention, the front foot and the rear foot out of the total of four front and rear feet are rotatably provided around the central axis. The legs of the lower part or the legs of the rear part rotate independently to change to a posture with less resistance, and can smoothly pass through the bent portion.

According to the invention of claim 4, since the piezoelectric elements are connected to both ends of the inertial body, the path length in one cycle becomes large as compared with the case where one piezoelectric element is used, and therefore the moving speed is increased. It becomes faster, and it is possible to eliminate the difference in operation between the case of moving forward and the case of moving backward.

[Brief description of drawings]

FIG. 1 is a partially sectional side view of an in-pipe moving device showing a first embodiment of the present invention.

FIG. 2 is a partially sectional front view of the in-pipe moving device.

FIG. 3 is a voltage waveform diagram showing one kind of sawtooth voltage waveform selected by the arbitrary waveform generator of the embodiment.

FIG. 4 is a view showing an action when a voltage of the same waveform is applied to advance the intra-tube moving device, and FIGS.
The figure is explanatory drawing shown in order of operation.

FIG. 5 is a voltage waveform diagram showing another type of sawtooth voltage waveform selected by the arbitrary waveform generator.

FIG. 6 is a view showing an action when the intra-tube moving device is moved forward by applying a voltage having the same waveform, and (6-A) to (6-D).
The figure is an explanatory view showing the order of operation.

FIG. 7 is an explanatory view showing an operation when the intra-pipe moving device advances along a bent pipe path, and FIGS. 7 (A) to 7 (C) are operation diagrams.

FIG. 8 is a side view, partly in section, of a moving device in a tube showing a second embodiment of the present invention.

FIG. 9 is a partially sectional front view of the in-pipe moving device.

FIG. 10 is a cross-sectional view of a pipe moving device showing a third embodiment of the present invention.

FIG. 11 is a front view of the in-pipe moving device.

FIG. 12 is a sectional view of a pipe moving device showing a fourth embodiment of the present invention.

[Explanation of Codes] 1 ... Weight (inertial body) 2a, 2b ... Laminated piezoelectric body 3 ... Shell 4a, 4b ... Front foot 4c, 4d ... Rear foot 7 ... Arbitrary waveform generator 8 ... Power supply 10 ... Piping 12 ... Bending conduit 20a, 20b ... Radiating fin 30 ... Spindle

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI technical display area // G02B 23/24 B62D 57/02 J

Claims (4)

[Claims] 1. An inertial body, and a piezoelectric element that is connected to the inertial body and expands and contracts by applying and releasing a voltage,
In the intra-tube moving device that moves by inertially driving the inertial body with this piezoelectric element, two feet that come into contact with the tube wall are provided at the front and rear ends of the device, and these two feet are An in-pipe moving device, which is provided symmetrically with respect to a central axis. 2. The in-pipe moving device according to claim 1, wherein a total of four front and rear legs are provided on a plane passing through the central axis. 3. The in-pipe moving device according to claim 1, wherein the front foot and the rear foot are provided so as to be rotatable relative to each other about a central axis. 4. The in-pipe moving device according to claim 1, further comprising piezoelectric elements which are connected to both ends of the inertial body so that when the other extends, the other contracts. .