JP7407994B2 - Pipe inner surface inspection method - Google Patents

Description

The present invention relates to a tube inner surface inspection method.

When measuring the inner diameter of the tube, a laser type measuring device can be used. Since measurement can be performed in a non-contact manner by using a laser, it is possible to eliminate the labor of centering work, position adjustment work, etc. that is required in contact-type measurement methods. In particular, the inner surface of the socket of an earthquake-resistant pipe has complex irregularities due to its structure, and the inner diameter is measured directly by a worker using a micrometer, etc., but this is inefficient and is prone to measurement errors. Because of this problem, there is a need for the development of a laser-type inner diameter measuring means.

As laser-type inner diameter measuring devices, there are, for example, devices disclosed in Patent Documents 1 to 3.

Japanese Patent Application Publication No. 04-16303 Japanese Patent Application Publication No. 2011-196899 Japanese Patent Application Publication No. 2000-105106

However, all of the conventional techniques have problems regarding the time required to measure the inner diameter. For example, the inner diameter inspection device disclosed in Patent Document 2 uses a reflector to change the direction of laser light emitted parallel to the tube axis in a direction perpendicular to the tube axis, but it can only measure one point on the inner surface of the tube. . Therefore, there is a problem that the inspection time is long.

One aspect of the present invention is to provide a pipe inner surface inspection method that can measure the inner diameter of a pipe socket more efficiently than conventional techniques, targeting a wide range of measurement targets along the pipe axis direction. do.

In order to solve the above-mentioned problems, a tube inner surface inspection method according to one aspect of the present invention is a tube inner surface inspection method for inspecting the inner surface of a tube in which an uneven shape is formed on the inner surface of a socket. The optical path of the emitted band-shaped laser beam that gradually becomes wider along the traveling direction of the laser beam is changed by a reflector provided inside the tube so that it travels in the direction toward the inner surface of the socket of the tube. a first step of spreading the laser beam whose optical path has been changed in the first step along the tube axis on the inner surface of the socket of the tube to be wider than the groove width of one annular groove included in the uneven shape; The method includes a second step of measuring the inner surface shape of the region by receiving the reflected light that is irradiated onto a region having at least the width and reflected by the light receiving section.

In the tube inner surface inspection method according to one aspect of the present invention, in the above structure, a first arrangement step of arranging an optical path changing section including the reflector at a predetermined first position inside the tube; a first rotation step of rotating the optical path changing section disposed at a first position around an axis parallel to the tube axis of the tube; and after the first rotation step, the optical path changing section is rotated around an axis parallel to the tube axis of the tube; a second positioning step of moving the optical path changing unit located at the second position along the axis to a predetermined second position; and a rotation direction in the first rotation step about an axis parallel to the tube axis. a second rotation step of rotating in the opposite direction, and in each step of the first rotation step and the second rotation step, the first step and the second step are repeated in this order a predetermined number of times. It may be.

In the pipe inner surface inspection method according to one aspect of the present invention, in the above structure, the direction in which the laser light modified by the reflection plate in the first step advances is approximately perpendicular to the inner surface of the socket of the pipe. It may be in the same direction.

According to one aspect of the present invention, by irradiating a relatively wide range with laser light along the axial direction of the pipe, the inner surface of the socket of the pipe can be inspected over a wide range. For example, since the inner diameter of the tube can be measured over a wide range along the tube axis, the inner shape of the tube can be quickly inspected.

1 is a diagram of a tube inner surface inspection device according to an embodiment of the present invention viewed from a certain angle; for convenience of explanation, the tube is a cross-sectional view along the tube axis direction; FIG. FIG. 2 is a view of the tube inner surface inspection apparatus shown in FIG. 1 when viewed from a direction rotated by 90 degrees with respect to the optical axis of a laser beam emitted from a light emitting section included in the tube inner surface inspection apparatus. This is a view of the reflection plate included in the tube inner surface inspection device shown in FIG. FIG. 3 is a diagram showing an optical path from irradiation to an inner surface, reflection, and reception by a reflection plate. In the tube inner surface inspection device shown in FIG. 2, the laser beam emitted from the light emitting section included in the tube inner surface inspection device is irradiated onto the inner surface of the tube, reflected, and is a diagram showing the optical path until the light is received by the light receiving section. be. FIG. 2 is a diagram schematically explaining a method of measuring the inner diameter of a tube using the tube inner surface inspection device according to an embodiment of the present invention. FIG. 2 is a diagram schematically explaining a method of measuring the inner diameter of a tube using the tube inner surface inspection device according to an embodiment of the present invention. FIG. 2 is a graph of actual measurement data when the inner surface shape of a tube is measured by the tube inner surface inspection device according to an embodiment of the present invention.

Hereinafter, one embodiment of the present invention will be described in detail. FIG. 1 is a diagram of a tube inner surface inspection device according to an embodiment of the present invention viewed from a certain angle, and for convenience of explanation, the tube is shown in a cross section along the tube axis direction. FIG. 2 is a view of the tube inner surface inspection apparatus shown in FIG. 1, as viewed from a direction rotated by 90 degrees around the optical axis of a laser beam emitted from a light emitting section included in the tube inner surface inspection apparatus.

The tube inner surface inspection device 1 of this embodiment is a tube inner surface inspection device that inspects the inner surface 110 of the tube 100. Inspecting the inner surface 110 of the tube 100 refers to measuring the inner diameter of the tube 100 and measuring the inner surface shape of the tube 100 based on the value of the inner diameter. An example of the inner surface shape of the pipe 100 is an uneven shape provided on the inner surface of the socket portion 101 of a cast iron pipe.

(Pipe inner surface inspection device)
The tube inner surface inspection device 1 shown in FIG. an optical path changing unit 3 that changes the laser beam toward the inner surface 110 of the tube 100 and irradiates a region A extending along the tube axis 100C, and receives the reflected light of the laser beam reflected from the region A of the inner surface 110; A light receiving section 4 is provided. According to this configuration, the inner surface 110 of the tube 100 can be inspected over a wide range by irradiating a relatively wide range with laser light along the tube axis direction of the tube 100. That is, since the inner diameter of the tube can be measured over a wide range along the tube axis direction, the inner surface shape of the tube can be quickly inspected.

Here, the pipe 100 may be, for example, a ductile cast iron pipe used as a water pipe or the like. Ductile cast iron pipes can be connected to each other by inserting a socket provided at one end of one iron pipe into a socket provided at the other end of another iron pipe. For this connection, the inner surface of the socket of the iron pipe has a stepped part for connection, a stepped part for attaching watertightness means (rubber rings) between the pipes, and an annular groove with an uneven shape. be. The tube 100 to be inspected in this embodiment also has an uneven shape including such an annular groove formed on the inner surface 110 of the socket portion 101.

Note that the tube 100 is supported by a tube support device (not shown). In this embodiment, the tube 100 is supported by a tube support device so that the tube axis 100C is substantially horizontal.

As shown in FIG. 1, the light emitting unit 2 emits a band-shaped laser beam that gradually becomes wider along the direction in which the laser beam travels. This band-shaped laser beam is made by combining a plurality of laser beams with their traveling directions parallel to each other, and each laser beam has the same wavelength. The wavelength is not particularly limited, but blue laser light is preferred. In the following description, a series of optical paths from light emitted from the light emitting unit 2 to being received by the light receiving unit 4 will be divided into four blocks. Specifically, a band-shaped laser beam on the optical path from being emitted from the light emitting unit 2 to entering the optical path changing unit 3 is referred to as 20a. Further, the band-shaped laser beam on the optical path from the time when the laser beam 20a changes its optical path at the optical path changing unit 3 until it is irradiated onto the region A of the inner surface 110 of the tube 100 is designated as 20b. Further, the band-shaped laser beam that is the reflected light on the optical path from being reflected in the area A to entering the optical path changing unit 3 is designated as 20c. The band-shaped laser beam on the optical path from when the reflected light 20c changes its optical path at the optical path changing unit 3 until it is received by the light receiving unit 4 is designated as 20d.

As shown in FIG. 1, the optical path changing unit 3 changes the optical path of the laser beam 20a emitted by the light emitting unit 2 toward the inner surface 110 of the tube 100 while being located inside the tube 100, and changes the optical path of the laser beam 20b to the inner surface 110 of the tube 100. A region A extending along the tube axis on the inner surface of the tube is irradiated. Region A is a region whose length along the tube axis is longer than the length along the tube axis of an irradiation region with a laser beam used in a general technique for irradiating the inner surface of a tube with a laser beam. For example, it is preferable that the length of region A along the tube axis has at least a width (length) wider than the groove width of one annular groove included in the uneven shape.

As shown in FIG. 2, the light receiving section 4 is provided at a position away from the tube axis 100C while the light emitting section 2 is at a position close to the tube axis 100C. The reflected light reflected at the region A of the inner surface 110 of the tube 100, specifically the band-shaped laser light 20d, is received. The light receiving section 4 includes a CMOS image sensor and outputs a signal based on the received laser light. The output signal is acquired by the calculation unit 6. In addition, in FIG. 2, the laser beam 20b that travels toward the inner surface 110 of the tube 100 travels toward the back of the page.

Here, the light receiving unit 4 can acquire the reflected light from the area A as height data. The light receiving section 4 uses the height data as an output signal. Thereby, the inner diameter of the tube can be specified by the calculating section 6, which will be described later. Note that the present invention is not limited to this, and the distance from the light receiving unit 4 to a specific position within the area A can be measured based on a well-known distance measurement technique using a laser beam. For example, it can be measured by the arrival flight time of laser light. As another example, the light receiving unit 4 is configured to generate a pattern projection image that captures shadows due to unevenness of the surface shape of the area A, and the distance to the area A is specified from the image. It may be.

Here, the light emitting section 2, the light receiving section 4, and the optical path changing section 3 are attached to an arm section 5 that includes a distal end section 51 that can be inserted into the inside of the tube 100. Specifically, the light emitting section 2 and the light receiving section 4 are arranged at the base 52 of the arm section 5, and the optical path changing section 3 is fixed to the tip section 51. By the arm part 5, the positions of the light emitting part 2, the light receiving part 4, and the optical path changing part 3 can be changed integrally. Since the distances between the two are constant, there is no need to control the positioning of both in the process of inspecting the inner surface of the tube, and the control mechanism can be simplified.

The arm section 5 is fixed to the tip of a robot arm 500, and the position and posture of the arm section 5 are adjusted by driving the robot arm 500. The robot arm 500 adjusts the position of the arm section 5 so that the axis 20L along the traveling direction of the laser beam 20a emitted from the light emitting section 2 is parallel to the tube axis 100C via the arm section 5. . Further, in the process of inspecting the inner surface 110 of the tube 100, the robot arm 500 rotates the arm portion 5 around the tube axis 100C. This will be discussed later. The installation mode of the arm section 5 is not limited to the example shown in FIG. 1 as long as it is provided at a position where it does not block the laser light from the light emitting section 2.

(Details of optical path changing part)
The optical path changing section 3 includes a reflecting plate 31 fixed to the tip end 51 of the arm section 5. The reflecting plate 31 adjusts the optical path by reflecting the laser beam 20a emitted by the light emitting section 2, and also reflects the reflected light 20c so that the reflected light 20c reflected on the inner surface 110 is directed toward the light receiving section 4. Adjust the optical path.

Specifically, as shown in FIG. 1, the optical path changing unit 3 allows the laser beam 20a emitted from the light emitting unit 2 to travel along one of the ends defining the width of the band-shaped laser beam 20a, and to be reflected at the reflecting plate 31 to pass through the tube 100. The optical path that enters the inner surface 110 of the tube 100 is defined as a first optical path (i). If the optical path incident on the tube 110 is the second optical path (ii), the reflecting plate 31 is configured to reflect the inner surface of the tube 100 for both the laser beam traveling in the first optical path (i) and the laser beam traveling in the second optical path (ii). A reflective surface 32 is directed toward the light emitting section 2 and the light receiving section 4 so as to receive and reflect the laser beam 20c reflected by the laser beam 110 and guiding it to the light receiving section 4 . Here, the first optical path (i) is defined at one of both ends defining the width of the band-shaped laser beam 20a in a series of optical paths emitted from the light emitting unit 2 and received by the light receiving unit 4. Further, the second optical path (ii) is defined at the other of the two ends that define the width of the band-shaped laser beam 20a in a series of optical paths emitted from the light emitting unit 2 and received by the light receiving unit 4.

The reflective surface 32 changes the optical path of the band-shaped laser beam 20a emitted from the light emitting section 2. At this time, at the center of the optical axis of the band-shaped laser beam 20a, the optical path is changed to a right angle by the reflective surface 32. At this time, a plane including the width direction of the band-shaped laser beam 20a before being received by the optical path changing unit 3 and a plane including the width direction of the band-shaped laser beam 20b after being reflected by the reflecting surface 32 are the same plane. It is in. This will be explained using FIG. 3.

FIG. 3 shows the reflection plate 31 included in the tube inner surface inspection device 1 shown in FIG. This is a diagram when the laser beam 20a emitted from the light emitting unit 2 included in the tube inner surface inspection device 1 is incident on the reflective surface 32 and reflected to become the laser beam 20b, which is irradiated onto the inner surface 110 of the tube 100. 3 is a diagram illustrating an optical path from reflection to reception by a reflection surface 32 of a reflection plate 31 as reflected light 20c. FIG.

In FIGS. 2 and 3, the incident position at which the laser beam on the first optical path (i) of the band-shaped laser beam 20a emitted from the light emitting unit 2 is incident on the reflective surface 32 is indicated by P1. Further, the incident position at which the laser beam on the second optical path (ii) of the band-shaped laser beam 20a emitted from the light emitting unit 2 is incident on the reflective surface 32 is indicated by P2. The laser beams incident on the incident positions P1 and P2 are reflected and have their optical paths changed, travel toward the inner surface 110 of the tube 100 as laser beams 20b, and are irradiated onto the inner surface 110 (area A). In order to change the optical path in this way, the reflective surface 32 is configured such that the incident position P2 side of the laser beam on the reflective surface 32 in the second optical path (ii) is at the back of the tube (the insertion port side), and the laser beam in the first optical path (i) is The direction from the incident position P1 side to the incident position P2 side of the laser beam on the reflecting surface 32 is inclined with respect to the axis 20L along the traveling direction of the laser beam 20a emitted from the light emitting part 2.

The laser beam 20b irradiated onto the area A on the inner surface 110 of the tube 100 is diffusely reflected on the inner surface 110 and becomes reflected light 20c. Here, the reflected light 20c has a predetermined inclination angle with respect to the laser light 20b incident on the area A. The predetermined inclination angle is, for example, 24.2°. In this embodiment, this can be achieved by using a laser beam with a directivity that generates reflected light having an angle of 24.2 degrees with respect to the laser beam 20b incident on the area A. . That is, when the laser beam of the first optical path (i) of the band-shaped laser beam 20b is irradiated to the area A, the reflected light (reflected light 20c, which is the band-shaped laser beam) having an angle of 24.2° with respect to the laser beam This becomes the first optical path (i)) of the laser beam. Moreover, when the laser beam of the second optical path (ii) of the band-shaped laser beam 20b is irradiated to the area A, the reflected light (the band-shaped reflected light 20c) having an angle of 24.2° with respect to the laser beam This becomes the second optical path (ii)) of the laser beam. Note that the angle of inclination of the reflected light 20c with respect to the laser beam 20b may be within a certain range, and is not limited to the pinpoint value of 24.2° as described above, for example. That is, 24.2° may be the average value or median value of the tilt angle, and does not mean that the laser beam has a directivity tilted at a pinpoint angle.

The reflected light 20c from the area A shown in FIGS. 2 and 3 is again received by the reflective surface 32, reflected, and directed toward the light receiving section 4. In FIGS. 2 and 3, P1r indicates the incident position at which the laser beam on the first optical path (i) of the band-shaped laser beam, which is the reflected light 20c, enters the reflective surface 32, and the laser beam on the second optical path (ii) The incident position of the light incident on the reflective surface 32 is indicated by P2r.

The laser beam 20d reflected on the reflective surface 32 toward the light receiving section 4 is received by the light receiving section 4. The details of the optical path changing section 3 have been described above. The inventors of the present invention guided the band-shaped laser beam used in this embodiment to area A on the inner surface of the tube to irradiate it, and guided the reflected light from area A to the outside of the tube to reach the light receiving section 4. After much effort and effort to receive the light, the optical path changing section 3 having the above-mentioned configuration was realized.

The calculation unit 6 specifies the inner diameter of the tube based on the output signal of the light receiving unit 4 and the position information of the light emitting unit 2. Note that the position information of the light emitting section 2 can be replaced by the position information of the arm section 5. To explain only the first optical path (i) of the band-shaped laser beam emitted from the light emitting part 2, from the optical path length of the first optical path from the light emitting part to the light receiving part and the position information of the light emitting part 2, It is possible to specify the inner diameter (radius) of the tube at the position (one location in area A) irradiated with the laser light of the first optical path. Moreover, if only the second optical path (ii) of the band-shaped laser beam emitted from the light emitting part 2 is explained, the optical path length of the second optical path from the light emitting part to the light receiving part and the position information of the light emitting part 2 will be explained. From this, it is possible to specify the inner diameter (radius) of the tube at the position (one location in area A) irradiated with the laser light of the second optical path. The calculation unit 6 can specify the inner diameter (radius) of the tube 100 at once for the entire area A by performing similar processing over the entire width of the band-shaped laser.

In this embodiment, by using the optical path changing unit 3 (reflector plate 31), it is possible to realize a mechanism for introducing a band-shaped laser beam emitted outside the tube into the spatially restricted interior of the tube 100. , and the band-shaped laser beam can be irradiated onto a region A extending along the tube axis. Further, by using the optical path changing section 3 (reflector plate 31), the optical path of the reflected light reflected from the area A can be changed toward the outside of the tube. This makes it possible to inspect the inner surface of the tube using a device that irradiates a band-shaped laser beam and identifies the shape of the surface of the irradiated area based on the reflected light from the irradiated area.

In addition, by being able to specify the inner diameter of area A at once in this way, it is possible to repeat measurements while changing the irradiation position along the tube axis using a so-called single laser beam that is not configured in a band shape. The inner diameter measurement speed is dramatically improved compared to the conventional method. This is advantageous in situations where it is necessary to quickly measure the inner diameter of a tube, such as on a production line for manufacturing tubes.

In order to be disposed in a spatially restricted pipe, the reflecting plate 31 has a right-angled trapezoidal reflecting surface 32 that tapers toward the back of the pipe. Note that the shape is not limited to this, and the reflective surface may have a square or rectangular shape.

Here, since area A is an area that extends along the tube axis direction and is not an area that extends along the inner circumference of the tube, so that it is possible to measure multiple locations along the inner circumferential surface, The light emitting section 2, the optical path changing section 3, and the light receiving section 4 can rotate integrally around an axis parallel to the tube axis 100C of the tube 100. This is achieved by the arm unit 5 being driven by the robot arm 500 and rotating integrally around an axis parallel to the tube axis 100C of the tube 100 (which may be the same as the tube axis 100C). be done.

(Applications other than inner diameter measurement)
Since the tube inner surface inspection device 1 of this embodiment can measure the inner diameter over the entire region A, it is also possible to measure the shape of the inner surface 110 of the region A. In other words, the width and depth of the uneven groove provided in the socket 101 of the tube 100 can be measured. Based on this measurement, it is possible to inspect whether or not the concavo-convex shape is formed with an appropriate size on the manufacturing line of the tube 100.

(Pipe inner surface inspection method)
The tube inner surface inspection method according to the present embodiment is a tube inner surface inspection method for inspecting the inner surface of a tube, in which a band-shaped laser beam 20a that is emitted from the light emitting section 2 and gradually becomes wider along the traveling direction of the laser beam. A first step of changing the optical path toward the inner surface 110 of the tube 100, and irradiating a region A extending along the tube axis on the inner surface 110 of the tube 100 with the laser beam 20b whose optical path has been changed in the first step. The method includes a second step of receiving the reflected light 20c by the light receiving section 4 and measuring the inner surface shape of the area A. According to this method, the inner surface 110 of the tube 100 can be inspected over a wide range by irradiating the laser beam over a relatively wide range along the tube axis direction of the tube 100. That is, since the inner diameter of the tube can be measured over a wide range along the tube axis direction, the inner surface shape of the tube can be quickly inspected.

As a pre-step to the first step, the tube 100 shown in FIG. 1, the light emitting section 2, and the light receiving section 4 are positioned. As an example, the tube support device is equipped with a positioning device that positions the tube by contacting the tube end. In this example, after the tube is temporarily supported by the tube support device, the position of the tube is moved so that the tube end contacts the positioning machine. To move the tube, a moving mechanism provided in the tube support device is used. By determining the position of the tube in this manner, the positional relationship between the tube 100, the light emitting section 2, and the light receiving section 4 becomes constant, and the arm section 5 can be placed at an accurate position by the robot arm 500. Thereby, the inner diameter of the pipe 100 can also be accurately measured by the calculation unit 6.

Below, an example of a tube inner surface inspection method in which a plurality of different locations along the inner circumferential surface of the tube 100 are irradiated with a band-shaped laser beam 20b and the inner surface shape is measured at each location will be described in FIGS. 4 and 5. Explain using.

FIG. 4 is a flow diagram showing an example of a tube inner surface inspection method. 5 is a diagram schematically showing the inside of the tube 100 when the tube axis 100C is arranged in the left-right direction in the drawing, and the right side in FIG. FIG. 4 is a plan view of the tube end portion viewed from outside the tube through section 4;

In the example of FIG. 4, a first arrangement step S1 of arranging the optical path changing section 3 at a predetermined first position inside the tube 100 and a first arrangement step S1 of arranging the optical path changing section 3 at a predetermined first position inside the tube 100 are performed. A first rotation step S2 of rotating around an axis parallel to the axis 100C, and a second arrangement step S3 of moving the optical path changing unit 3 to a predetermined second position along the tube axis 100C after the first rotation step S2. and a second rotation step S4 in which the optical path changing unit 3 disposed at a predetermined second position is rotated about an axis parallel to the tube axis 100 in a direction opposite to the rotation direction in the first rotation step S2. include. In each step of the first rotation step S2 and the second rotation step S4, the above-mentioned first step and second step are repeated a predetermined number of times in this order.

Prior to the first arrangement step S1, the tube 100 described above, the light emitting section 2, the light receiving section 4, and the optical path changing section 3 (robot arm 500 (FIGS. 1 and 2)) are positioned. Thereby, by moving the robot arm 500 according to a predetermined program, the optical path changing unit 3 can be placed at a predetermined position.

In the first arrangement step S1, the optical path changing section 3 is arranged at a predetermined first position within the tube 100. This will be explained using FIG. 5, for example. The left side of FIG. 5 shows how the optical path changing unit 3 is arranged at the first position 100A within the tube 100. The light emitting unit 2, the light receiving unit 4, and the optical path changing unit 3 are separated by a predetermined length (for example, 100 mm), and the distance from the center position of the reflective surface 32 of the optical path changing unit 3 to the reference position is a predetermined distance. (for example, 100 mm). Note that the reference position indicates the design dimension and can be changed to the + side or the - side.

In the first rotation step S2, the optical path changing unit 3 placed at the first position 100A in the first placement step S1 is rotated about the tube axis 100C of the tube 100. This can be realized by rotating the arm portion 5 around the tube axis 100C. The right side of FIG. 5 shows the position of the optical path changing unit 3 from 0° along the inner circumference of the tube 100 centering on the tube axis 100C, assuming that the arrangement of the optical path changing unit 3 shown on the left side of FIG. 5 is 0°. It is specified within a 360° range. Note that the optical path changing unit 3 may rotate around the tube axis 100C of the tube 100, but as long as it is parallel to the tube axis 100C of the tube 100, it does not have to be coaxial with the tube axis 100C of the tube 100. Good too. By accurately specifying the positional relationship between the arm section 5 and the tube 100, the inner diameter can be accurately measured even if the rotation center of the optical path changing section 3 is shifted from the tube axis 100C of the tube 100. Further, for example, when the nominal diameter of the tube is large, it is necessary to adjust the position of the light receiving section 2 in the radial direction of the tube. To cope with such a case, it is also possible to provide a mechanism for adjusting the position of the light receiving section 2 (arm section 5) in the radial direction of the tube. For example, a robot arm may be used to adjust the position of the light receiving section 2 (arm section 5) in the radial direction of the tube.

In the first rotation step S2, the optical path changing unit 3 starts rotating from the 0° position, and rotates the optical path changing unit 3 counterclockwise in the order of 90°, 180°, and 270° as shown on the right side of FIG. Rotate.

Moreover, in the first rotation step S2, the optical path changing unit 3 is rotated intermittently. In one example, as shown on the right side of FIG. 5, the rotation of the arm portion 5 is temporarily stopped at each of the 0° position, 90° position, 180° position, and 270° position. In other words, the robot arm pauses rotation every 90 degrees of rotation. Then, during the temporary stop, the above-mentioned first step and second step are performed using the optical path changing section 3.

Taking the 0° position as an example, the optical path of the band-shaped laser beam 20a that is emitted from the light emitting unit 2 at the 0° position in the first step and gradually becomes wider along the traveling direction of the laser beam is as follows. , the optical path is changed toward the 0° position of the inner surface 110 of the tube 100 by the optical path changing unit 3 located at the 0° position. Then, in the second step, the laser beam is irradiated onto a region A extending along the tube axis at the 0° position of the inner surface 110 of the tube 100 and reflected, and the reflected light 20d whose optical path is changed by the optical path changing section 3 is generated. , the light is received by the light receiving section 4, and the inner surface shape of the area A is measured.

These first and second steps are also performed at the 90° position, the 180° position, and the 270° position. In the first rotation step S2, the rotation may be terminated (stopped) when the rotation reaches the 270° position.

Through the above steps up to the first rotation step S2, the inner diameter of the tube 100 can be determined as follows;
Inner diameter of the tube between “0° position” and “180° position” =
Light reception result of the light receiving section at the position of R+0° + Light receiving result of the light receiving section at the position of 180°
Inner diameter of tube between “90° position” and “270° position” =
Result of light reception by the light receiver at the position R+90° Result of light reception by the light receiver at the position +270° Note that R in the formula is the rotational diameter R of the arm portion 5 shown on the right side of FIG.

Note that the position at which the rotation of the optical path changing unit 3 is temporarily stopped is not limited to the illustrated example. Further, the number of times of temporary stopping can be appropriately set to two or more times, preferably four or more times as illustrated on the right side of FIG. As illustrated on the right side of FIG. 5, two positions (for example, 0° position and 180° position) that are symmetrical (180°) about the tube axis 100C are considered as one set, and multiple sets are arranged in the rotation direction. Just set it accordingly. When the rotation angle of the arm part 5 is controlled to be temporarily stopped every 60°, the rotation angle of the arm part 5 is controlled to be temporarily stopped at every 60°, the 0° position, the 60° position, the 120° position, the 180° position, the 240° position, and the 300° position. The rotation may be temporarily stopped at a certain position, and the above-described first step and second step may be performed at each position.

In the example of FIG. 4, further, after the first rotation step S2, a second placement step S3 is performed in which the optical path changing unit 3 is moved toward the back of the tube to a predetermined second position along the tube axis 100C. FIG. 6 is a diagram showing a state in which the optical path changing unit 3 is placed at a predetermined second position 100B within the tube 100. Note that movement from the first position 100A (FIG. 5) to the second position 100B can be realized by moving the arm portion 5 in a direction parallel to the tube axis 100C. The first rotation step S2 described above ends the rotation at the 270° position shown on the right side of FIG. Therefore, the second arrangement step S3 is performed in a state where the optical path changing section 3 is located at a position of 270 degrees. When the second arrangement step S3 is completed, a second rotation step S4 is performed.

In the second rotation step S4, the optical path changing unit 3 located at the second position 100B shown on the left side of FIG. 6 is rotated about the tube axis 100C of the tube 100. The rotation mechanism is the same as the first rotation step S2, but differs in that the rotation direction is opposite to that of the first rotation step S2. That is, in the second rotation step S4, the rotation of the optical path changing unit 3 is started from the 270° position, and the optical path changing unit 3 is rotated clockwise in the order of the 180° position, the 90° position, and the 0° position. It is rotated in the direction of the arrow shown on the right side of FIG. 6, and the rotation is temporarily stopped at each position similarly to the first rotation step S2. Then, during the temporary stop, the above-mentioned first step and second step are performed using the optical path changing section 3. Since this has been explained in the first rotation step S2, the explanation will be omitted.

In the above second rotation step S4, when the light receiving result is obtained from the light receiving section at the final 0° position, the robot arm moves the optical path changing section 3 out of the tube via the arm section 5. At this time, with the optical path changing part 3 at the 0° position, the optical path changing part 3 pulled out to the outside of the tube along the tube axis 100C is moved from the tube end of the new tube placed at a predetermined position again. By being inserted into the tube along the tube axis, the first placement step S1 can be started without unnecessary movement. This allows the arm portion to be moved efficiently when inspecting the inner surface of the tube midway through the tube manufacturing line, contributing to improved inspection efficiency.

By measuring the inner diameter of the tube at multiple locations along the tube axis (first position and second position) as described above, the inner diameter can be continuously obtained over a wide range along the tube axis, and the inner diameter By connecting the values along the tube axis direction, the shape of the inner surface of the tube can be measured. FIG. 7 shows a profile of the shape of the inner surface of the tube obtained by connecting the inner diameter values along the tube axis direction in this manner. In FIG. 7, the inner surface of the socket of the cast iron pipe described above was inspected, and the uneven shape provided on the inner surface is clearly shown on the profile. By using this profile data, it is possible to measure the depth and width of the annular groove forming the uneven shape. Therefore, it is also possible to inspect whether the inner surface of the socket part is formed as designed.

Note that one aspect of the present invention is a tube inner surface inspection device for inspecting the inner surface of a tube, which includes: a light emitting section that emits a band-shaped laser beam that gradually becomes wider along the direction in which the laser beam travels; and the light emitting section emitting light. an optical path changing unit that changes the optical path of the laser beam toward the inner surface of the tube and irradiates the laser beam to a region spread along the tube axis on the inner surface of the tube; A tube inner surface inspection device includes a light receiving section that receives reflected light of the laser beam.

According to the above configuration, the inner surface of the tube can be inspected over a wide range by irradiating the laser beam over a relatively wide range along the axial direction of the tube. For example, since the inner diameter of the tube can be measured over a wide range along the tube axis, the inner shape of the tube can be quickly inspected.

In the tube inner surface inspection device according to one aspect of the present invention, in the above configuration, the arm section includes a distal end section that can be inserted into the inside of the tube, and the optical path changing section is a reflective tube fixed to the distal end section. The reflecting plate adjusts the optical path by reflecting the laser light emitted by the light emitting section, and also directs the reflected light so that the reflected light reflected on the inner surface is directed toward the light receiving section. The light emitting section and the light receiving section may be arranged at a base of the arm section.

According to the above configuration, since the distance between the reflecting plate and the light emitting part and the distance between the reflecting plate and the light receiving part are each constant, there is no need to control the positioning of both in the inner surface inspection process. The control mechanism can be simplified.

In the pipe inner surface inspection device according to one aspect of the present invention, in the above configuration, the band-shaped laser light is emitted from the light emitting part, travels along one of both ends defining the width, is reflected on the reflector plate, and is reflected on the tube A first optical path is defined as an optical path that enters the inner surface of the tube, and is emitted from the light emitting part, travels through the other of the two ends that define the width of the band-shaped laser beam, is reflected by the reflector, and enters the inner surface of the tube. When the optical path is a second optical path, the reflecting plate receives and reflects the laser beam reflected on the inner surface of the tube for both the laser beam traveling in the first optical path and the laser beam traveling in the second optical path. , a reflective surface may be oriented toward the light emitting section and the light receiving section so as to guide the light to the light receiving section.

According to the above configuration, the reflective surface of the reflector plate allows the band-shaped laser beam to be irradiated over a relatively wide range along the tube axis direction of the tube, and the inner surface of the tube is irradiated over a wide range and reflected. Laser light can be received by the light receiving section.

In the tube inner surface inspection device according to one aspect of the present invention, in the above configuration, the tube inner surface inspection device may further include a calculation section that specifies the inner diameter of the tube using the position of the light emitting section and the light reception result of the light receiving section. good.

According to the above configuration, the inner diameter of the tube can be evaluated.

In the tube inner surface inspection device according to one aspect of the present invention, in the above configuration, the light emitting section, the optical path changing section, and the light receiving section are integrally rotated about an axis parallel to the tube axis of the tube. It may be rotatable.

According to the above configuration, the entire inner circumference of the tube can be measured.

Further, in order to solve the above-mentioned problems, a tube inner surface inspection method according to one aspect of the present invention is a tube inner surface inspection method for inspecting the inner surface of a tube. a first step of changing the optical path of a band-shaped laser beam that gradually becomes wider along the tube axis toward the inner surface of the tube; The method includes a second step of measuring the inner surface shape of the region by receiving the reflected light that has been irradiated onto the expanded region and reflected by the light receiving section.

According to the above configuration, the inner surface of the tube can be inspected over a wide range by irradiating the laser beam over a relatively wide range along the axial direction of the tube. For example, since the inner diameter of the tube can be measured over a wide range along the tube axis, the inner shape of the tube can be quickly inspected.

In the pipe inner surface inspection method according to one aspect of the present invention, in the above structure, the first step is to change the optical path of the band-shaped laser beam emitted from the light emitting part by an optical path changing part, and the inside of the pipe The surface inspection method includes a first arranging step of arranging the optical path changing section at a predetermined first position inside the tube; a first rotation step of rotating around an axis parallel to the tube; a second positioning step of moving the optical path changing section to a predetermined second position along the tube axis after the first rotation step; a second rotation step of rotating the optical path changing section disposed at a second position of the optical path changing section around an axis parallel to the tube axis in a direction opposite to the rotation direction in the first rotation step; In each of the one rotation step and the second rotation step, the first step and the second step may be repeated a predetermined number of times in this order.

According to the above configuration, since the rotation direction of the first rotation step and the rotation direction of the second rotation step are opposite to each other, it is possible to avoid a situation in which the wiring connected to the light receiving section etc. becomes tangled due to rotation. can.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims.

1 Pipe inner surface inspection device 2 Light emitting unit 3 Optical path changing unit 4 Light receiving unit 5 Arm unit 6 Computing units 20a, 20b, 20c, 20d Band-shaped laser beams 20c, 20d Reflected light 31 Reflecting plate 32 Reflecting surface 51 Tip 52 Base 100, 100C Pipe shaft 100A 1st position 101 Socket part (socket)
110 Inner surface 500 Robot arm S1 First placement process S2 First rotation process S3 Second placement process S4 Second rotation process (i) First optical path (ii) Second optical path

Claims (3)

A tube inner surface inspection method for inspecting the inner surface of a tube in which an uneven shape is formed on the inner surface of a socket,
A band-shaped laser beam emitted from a light emitting part that gradually becomes wider along the direction of travel of the laser beam is guided along an optical path toward the inner surface of the socket of the tube by a reflector provided inside the tube. The first step of changing the
Spreading the laser beam whose optical path has been changed in the first step along the tube axis on the inner surface of the socket of the tube to a region having at least a width wider than the groove width of one annular groove included in the uneven shape. A method for inspecting an inner surface of a tube, comprising: a second step of receiving reflected light that has been irradiated and reflected by a light receiving section, and measuring the inner surface shape of the region. a first arranging step of arranging an optical path changing section including the reflector at a predetermined first position inside the tube;
a first rotation step of rotating the optical path changing unit disposed at the predetermined first position about an axis parallel to the tube axis of the tube;
a second positioning step of moving the optical path changing unit to a predetermined second position along the tube axis after the first rotation step;
a second rotation step of rotating the optical path changing unit disposed at the predetermined second position about an axis parallel to the tube axis in a direction opposite to the rotation direction in the first rotation step;
including;
2. The tube inner surface inspection method according to claim 1, wherein in each of the first rotation step and the second rotation step, the first step and the second step are repeated in this order a predetermined number of times. The tube inner surface according to claim 1, wherein the direction in which the laser light modified by the reflector in the first step advances is substantially perpendicular to the inner surface of the tube socket. Inspection method.

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