JPH08207756A - In-hole self-traveling survey instrument - Google Patents

Abstract

PURPOSE: To provide an in-hole self-traveling inspection instrument that can keep spaces between plural sensors and the inner wall surface of a hole almost constant in spite of the inclination of the inspection instrument in the hole or the bending of the hole. CONSTITUTION: An in-hole self-traveling inspection instrument is provided with a piezoelectric laminated actuator 1 expanded by applied voltage, a weight 2 fixed to one end of the actuator 1, a leg part 3 fixed to the other end of the actuator 1 and brought into contact with the inner wall surface W forming a surrounding hole, sensors 4 held to the actuator 1 or the leg part 3 so as to be provided near the inner wall surface W with which the leg part 3 comes in contact, and a control means for supplying applied voltage to the actuator 1. Since the sensors 4 are provided near the inner wall surface W with which the leg part 3 comes in contact, spaces between the sensors 4 and the inner wall surface W hardly change in spite of a slanting attitude to the hole or the bending of the hole, so that stable sensor output can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting the inside of a pipe or a pipe wall, which is equipped with various kinds of sensors and moves by itself in a hole of a pipe or the like. In-hole self-propelled inspection device suitable for The piping is
In addition to industrial piping, domestic piping for gas and water, nuclear reactor piping, etc., living body pipelines, etc. are also included.

[0002]

2. Description of the Related Art As a conventional self-propelled in-hole inspection device, there is a self-propelled in-pipe device disclosed in Japanese Patent Laid-Open No. 4-176770. As shown in FIG. 10, this has a front end member 102 at the front end and a rear end member 130 at the rear end of a laminated piezoelectric element 101 that can expand and contract in the axial direction by an applied voltage. The balloon 13 provided on the outer peripheral surface of the rear end member 130
1 abuts on a peripheral wall surface W forming a hole and supports an in-hole moving body 100 including a piezoelectric element 101, a front end member 102, and a rear end member 130. Also, the front end member 10
An optical fiber 104 is equipped at the tip of 2 as a sensor.

This in-hole moving device is provided with a control means (not shown), which controls the voltage applied to the piezoelectric element 101, and expands and contracts the piezoelectric element 101 with gradual speed. Accordingly, the difference between the frictional force generated between the balloon 131 and the wall surface W contacting the balloon 131 and the inertial force generated by the front end member 102 due to the expanding and contracting piezoelectric element 101 is used to move forward or backward little by little. be able to.

[0004]

However, following the example of the optical fiber 104, the front end member 1 of the hole moving device described above is used.
If the 02 is equipped with the eddy current type flaw detection sensor 140, the following inconvenience occurs. That is, as shown in FIG. 11, when the in-hole moving body 100 tilts with respect to the hole formed by the inner wall surface W, the plurality of flaw detection sensors 140 mounted on both sides of the front end of the front end member 102 and the inner wall surface W are separated. The intervals become non-uniform and sufficient sensor sensitivity cannot be obtained. Also, as shown in FIG. 12, even if the hole is bent,
The distance between the flaw detection sensor 140 and the inner wall surface W becomes uneven, and the same inconvenience occurs.

Therefore, the present invention provides a self-propelled in-hole inspection device capable of maintaining a substantially constant distance between a plurality of sensors and the inner wall surface of the hole, despite the inclination of the device and the bending of the hole in the hole. Providing is a problem to be solved.

[0006]

In a self-propelled in-hole inspection apparatus having a first structure according to the present invention, a piezoelectric laminated actuator capable of expanding and contracting in the axial direction by an applied voltage and fixedly held at one end of the actuator in the axial direction. A weight, a leg portion fixedly held at the other axial end of the actuator and abutting against an inner wall surface forming a peripheral hole; and an inner wall surface held by the actuator or the leg portion and abutting the leg surface. It is characterized in that it is provided with a sensor provided in the vicinity and a control means for supplying an applied voltage having a controlled waveform to the actuator.

A second embodiment of the self-propelled in-hole inspection device of the present invention is
In the first configuration, further, the leg portion includes a base member fixed to the actuator and a plurality of clamp legs whose one end is supported by the base member, and the sensor includes
It is disposed near the inner wall surface that is supported by the base member and abuts the clamp legs. In the hole self-propelled inspection device of the 3rd structure of this invention, in the said 1st structure, the said leg part is further equipped with the base member fixed to the said actuator, and the some clamp leg which one end was supported by this base member. And the sensor is supported on the other end of the clamp leg.

A fourth embodiment of the self-propelled in-hole inspection device of the present invention is
In the first structure, the leg portion is further made of a spring elastic material. In the hole self-propelled inspection device of the fifth configuration of the present invention, the sensor is an eddy current flaw detection sensor in the first configuration. In the hole self-propelled inspecting device of the sixth configuration of the present invention, in the first configuration, the sensor is further brought into contact with the inner wall surface by an abutting surface formed by a convex curved surface. Here, it is also possible to adopt a configuration in which the sensor is in contact with the inner wall surface by a protrusion such as a small protrusion having a convex curved surface.

[0009]

In the self-propelled in-hole inspection apparatus of the first structure according to the present invention, the control means controls the voltage applied to the piezoelectric laminated actuator, and the actuator is gradually expanded and contracted. Inertia force that causes weight,
By utilizing the difference between the leg portion and the frictional force generated between the leg portion and the inner wall surface contacting the leg portion, the leg portion can be moved forward or backward little by little.

At this time, even if the device is tilted with respect to the hole or the hole is bent, since the sensor is provided in the vicinity of the inner wall surface with which the leg portion abuts, the distance between the sensor and the inner wall surface of the hole is large. Changes little and remains almost constant. As a result, the sensitivity of the sensor for inspecting the wall surface or the inside of the wall surface can be kept constant. In the hole self-propelled inspection device of the second configuration of the present invention, since the plurality of clamp legs contact the inner wall surface of the hole,
The legs can be stably supported on the axial center of the hole, and
It is possible to cope with a change in the inner diameter of the hole to some extent.

In the in-hole self-propelled inspection device of the third structure of the present invention, since the sensor is supported on the tip of the clamp leg,
The tip of the sensor contacts the inner wall surface of the hole to support the leg.
As a result, there is an effect that the distance between the tip of the sensor and the inner wall surface does not change, and there is almost no change in sensor sensitivity. In the in-hole self-propelled inspection device of the fourth structure of the present invention, since the leg portion is in contact with the inner wall surface of the hole with spring elasticity, the contact force is kept substantially constant regardless of a slight change in the inner diameter of the hole. . As a result, it becomes possible to cope with a change in the inner diameter of the hole to some extent. Further, it becomes possible to manufacture the legs with a simple and highly reliable structure without bearings or sliding parts.

The hole self-propelled inspection device of the fifth structure of the present invention is equipped with an eddy current type flaw detection sensor, so that the distance between the sensor and the inner wall surface of the hole can be kept substantially constant. The effect can be sufficiently exerted, and the sensitivity of the flaw detection sensor, which is weak against the change in the interval, can be kept constant. Sixth of the present invention
In the in-hole self-propelled inspection device having the configuration, since the contact surface of the sensor has a convex curved surface, even if the leg portion is inclined with respect to the inner wall surface of the hole, the sensor contact is made by point contact or line contact. The contact surface and the inner wall surface of the hole are in contact with each other, and the distance therebetween does not change. as a result,
The effect that even more stable sensor sensitivity is obtained is produced. This effect can be obtained in the same manner by means of providing a small protrusion on the contact portion of the sensor.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. (Structure of First Embodiment) As shown in FIG. 1, a self-propelled in-hole inspection apparatus as a first embodiment of the present invention includes a piezoelectric laminated actuator 1, a weight 2 fixedly held at the tip thereof, and an actuator 1. The in-hole moving body 10 having the leg portion 3 fixedly held at the rear end is provided. The moving body 10 is equipped with two sensors 4 on the leg portion 3. Further, the in-hole self-propelled inspection apparatus of this embodiment is provided with a control means (not shown) for supplying an applied voltage having a waveform controlled by the electric wire (not shown) to the actuator 1 outside the hole.

The actuator 1 is a well-known element having a structure in which a large number of piezoelectric elements, the thickness of which changes with applied voltage, are inserted by inserting electrodes, and the actuator 1 expands and contracts in the axial direction when the applied voltage changes. The weight 2 is a highly rigid and sturdy metal weight (mass body), and is composed of a hemispherical head 20 fixed to the tip of the actuator 1 at the central portion on the plane side and an outer peripheral portion on the same plane side. Hollow cylindrical body 2 extending in the direction of the leg 3
It consists of 1. The body portion 21 is formed to have a length that does not come into contact with the leg portion 3 even if the actuator 1 is fully contracted, and increases the mass of the weight 2 without biasing the center of gravity to the front so much that movement by the actuator 1 is prevented. Making it easy. Further, the body portion 21 covers and protects most of the actuator 1, and at the same time, a proper gap is formed between the body portion 21 and the leg portion 3 to help the actuator 1 to naturally radiate heat. However, when it is desired to protect and isolate the internal space of the body 21 from the external environment, the gap between the body 21 and the leg 3 may be airtightly connected by a bellows or a rubber elastic film.

The leg portion 3 is composed of a base member 30 fixed to the rear end of the actuator 1 and four clamp legs 31 whose one end is supported by the base member 30. The base member 30 is a rectangular parallelepiped member made of a light alloy, and supports the clamp leg 31 and the sensor 4. The clamp leg 31 is a wire-shaped member made of a spring alloy and has one end fixedly supported by the base member 30 and the other end extending rearward and contacting the inner wall surface W of the hole at a shallow angle. The four clamp legs 31 are not opened 90 degrees at a time, but are extended by inserting the sensor 4 described later as a set of two, and come into contact with the inner wall surface W in the vicinity of the sensor 4 so that the moving body 10 is fixed. It supports the inner wall surface W of the hole.

The sensor 4 is a well-known eddy current type flaw detection sensor, the main part of which is composed of a bobbin and a coil. The sensor 4 is supported by metal pipes 43 protruding rearward from both ends of the rear end face of the base member 31 and is fixedly held at a position sandwiched by the pair of clamp legs 31 described above. . The axis of the coil of the sensor 4 is oriented substantially perpendicular to the inner wall surface W of the hole, and its detection end face faces the inner wall surface W with a slight distance. In addition, pipe 4
An electric wire for driving the sensor 4 and transmitting a measurement signal is arranged in the wiring 3, and is connected to a measurement recording device outside the hole by an electric wire (not shown) that crawls in the hole.

The above is the structure of the moving body 10 equipped with the sensor 4, and the moving body 10 and the control means for supplying the applied voltage for driving the moving body 10 constitute the self-propelled in-hole inspection apparatus of this embodiment. There is. The role of the moving body 10 is to carry the sensor 4 to an appropriate position in the hole and to make the sensor 4 face or abut on the inner wall surface W at an appropriate angle and distance. Therefore, as described above, the electric cable (not shown) is connected to the moving body 10 and is connected to the control means and the measurement recording device outside the hole.

(Effects of Embodiment 1) In the hole self-propelled inspection apparatus of this embodiment, the voltage applied to the actuator 1 is controlled by the control means, and the actuator 1 is gradually expanded and contracted. The inertial force that causes the weight 2 and
By utilizing the difference between the frictional force generated between the leg portion 3 and the inner wall surface W with which the leg portion 3 abuts, the leg portion 3 can be gradually moved forward or backward.

At this time, even if the moving body 10 is tilted with respect to the hole as shown in FIG. 2 or the hole is bent as shown in FIG. 3, the sensor 4 has an inner wall surface against which the clamp leg 31 abuts. Since it is provided in the vicinity of W, the distance between the sensor 4 and the inner wall surface W of the hole hardly changes and is kept substantially constant.
As a result, there is an effect that the sensitivity of the sensor 4, which is an eddy current flaw detection sensor for inspecting the inside of the inner wall surface W, can be kept constant.

Since the plurality of clamp legs 31 have spring elasticity and come into contact with the inner wall surface W of the hole, the leg portion 3 can be stably supported near the axial center of the hole, and the inner diameter of the hole can be reduced. You will be able to respond to changes to some extent. Further, the leg portion 3 has an effect that it has a simple and highly reliable structure. (Embodiment 2) The self-propelled in-hole inspection apparatus of this embodiment is equipped with an eddy current flaw detection sensor 4 at the tip of the clamp leg 32, as shown in FIG.

Here, the piezoelectric laminated actuator 1, the weight 2, the base member 30 and the clamp leg 32 forming the leg portion 3, and the sensor 4 constitute the in-hole moving body 10 in the above-described embodiment. The same as 1. However, in this embodiment, the support structure of the leg 3 and the sensor 4 is different. That is, the leg portion 3 is composed of a base member 30 made of a light alloy having a regular polygonal column shape, and a plurality of clamp legs 32 each having one end bonded and fixed to a hole formed in the rear end surface of all corner portions thereof. It Each clamp leg 32 is a pipe-shaped member made of a spring alloy, and the sensor 4 is provided at the other end.
It is supported with the contact surface of the detection end facing the inner wall surface W of the hole. In the holes, the contact surfaces of all the sensors 4 are in contact with the inner wall surface W of the holes with a light pressing force due to the elastic force of each clamp leg 32.

Therefore, the movable body 10 of the in-hole self-propelled inspection apparatus of this embodiment moves forward or backward to move in the hole according to the same operation principle as in the first embodiment, and the inner wall surface of the hole to be inspected for the sensor 4 is moved. It can be brought into contact with the W portion. At this time, even if the moving body 10 is inclined with respect to the hole as shown in FIG. 5 or the hole is bent as shown in FIG. 6, the sensor 4 remains in contact with the inner wall surface W. , The distance between the sensor 4 and the inner wall surface W of the hole does not change and is kept constant. As a result, there is an effect that the sensitivity of the eddy current type flaw detection sensor 4 can be kept constant.

Further, in this embodiment, in addition to producing the same effect as that of the first embodiment, the clamp leg 32 also serves as a support member of the sensor 4, so that the structure is simpler, and the inside of the hole is lightweight and has high performance and few failures. There is also an advantage that a self-propelled inspection device can be provided. The clamp leg 32 may be formed of a strip-shaped member made of a plate material made of a spring alloy, and the spring constant may be lowered to allow the sensor 4 to be supported more flexibly. According to this configuration, there is an effect that the change in the hole diameter can be more flexibly dealt with. in this case,
The leg portion 3 including the clamp leg 32 is set to the ground side, and one output signal line is output from each sensor 4 and the sensor 4
Are grouped into a single cable at the center where
It is recommended to lead to the measurement recording device outside the hole.

(Modification) In the second embodiment described above, the shape of the contact surface where the eddy current type flaw detection sensor 4 contacts the inner wall surface W of the hole is not dared to mention. Therefore, it is common sense to make the contact surface flat as in the case of an ordinary sensor, but it is possible to obtain more stable sensor sensitivity by devising the shape of the contact surface.

That is, as shown in FIG. 7, the sensor 4 of the second embodiment comprises a bobbin 42 supported by the clamp leg 32 and a coil 41 wound around the bobbin 42. At the other end of the coil 41, a member made of a soft magnetic material that is connected to the bobbin 42 forms a contact surface 40 and contacts the inner wall surface W of the hole. Here, as shown in FIG.
Is formed as a convex curved spherical surface, the contact surface 40 continues to contact the inner wall surface W at its center even when the moving body of the in-hole self-propelled inspection device is tilted with respect to the hole. Therefore, there is almost no change in the sensor sensitivity, and more stable measurement can be performed.

Also, as shown in FIG. 8, a small projection 44 having a hemispherical tip is provided at the center of the tip of the sensor 4,
Since the contact surface is formed by the convex curved surface, the sensitivity does not change due to the posture change, and stable measurement can be performed. Further, as shown in FIG. 9, even if the tip of the small protrusion 45 provided at the tip of the sensor 4 is not round, if the diameter of the small protrusion 45 is sufficiently smaller than the diameter of the sensor 4, the same effect can be obtained. You can

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing the configuration of an in-hole self-propelled inspection device according to a first embodiment.

FIG. 2 is a side view showing the in-hole self-propelled inspection device according to the first embodiment tilted with respect to the hole.

FIG. 3 is a side view showing the in-hole self-propelled inspection device according to the first embodiment in a bent hole.

FIG. 4 is a partial cross-sectional side view showing the configuration of the in-hole self-propelled inspection device according to the second embodiment.

FIG. 5 is a side view showing an in-hole self-propelled inspection device according to a second embodiment tilted with respect to the hole.

FIG. 6 is a side view showing the in-hole self-propelled inspection device according to the second embodiment in a bent hole.

FIG. 7 is a side view showing a shape of a sensor that abuts an inner wall surface of a hole.

FIG. 8 is a side view of a sensor having a small protrusion that abuts the inner wall surface of the hole.

FIG. 9 is a side view of a sensor having a small protrusion of another shape that abuts the inner wall surface of the hole.

FIG. 10 is a partial cross-sectional side view showing the configuration of a conventional in-hole self-propelled inspection device.

FIG. 11 is a side view showing a conventional self-propelled in-hole inspection device tilted with respect to a hole.

FIG. 12 is a side view of a prior art self-propelled in-hole inspection device in a bent hole.

[Explanation of symbols]

10: In-hole moving body 1: Piezoelectric laminated actuator
2: Weight 3: Leg part 30: Base member 31, 32: Clamp leg 4: Sensor 40: Contact surface 41, 42: Small protrusion
43: Pipe W: Inner wall surface (of hole)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G21C 17/003 17/08

Claims (6)

[Claims] 1. A piezoelectric laminated actuator capable of expanding and contracting in an axial direction by an applied voltage, a weight fixedly held at one axial end of the actuator, and a peripheral hole fixedly held at another axial end of the actuator. A leg portion that abuts an inner wall surface of the actuator, a sensor that is held by the actuator or that is provided near the inner wall surface that abuts the leg portion, and an applied voltage of a waveform controlled by the actuator. An in-hole self-propelled inspection device comprising: a supply control unit. 2. The leg portion includes a base member fixed to the actuator and a plurality of clamp legs whose one end is supported by the base member, and the sensor is supported by the base member and the clamp legs are The self-propelled in-hole inspection device according to claim 1, wherein the self-propelled in-hole inspection device is disposed in the vicinity of the abutting inner wall surface. 3. The leg portion includes a base member fixed to the actuator and a plurality of clamp legs whose one end is supported by the base member, and the sensor is supported on the other end of the clamp leg. The self-propelled in-hole inspection device according to claim 1. 4. The in-hole self-propelled inspection device according to claim 1, wherein the leg portion is formed of a spring elastic material. 5. The hole self-propelled inspection apparatus according to claim 1, wherein the sensor is an eddy current flaw detection sensor. 6. The in-hole self-propelled inspection device according to claim 1, wherein the sensor is in contact with the inner wall surface by an abutting surface formed of a convex curved surface.