JPH0743119A - Tube size measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain the dimensions such as the inner diameter of a pipe with a simple structure and with high accuracy. A laser displacement meter 2 having a long lift-off equal to or larger than a radius of a tube body 1 is used, and a laser beam Ba emitted from the laser displacement meter in a tube axis direction is reflected by a reflector 3 in a radial direction.
The laser beam Bb is rotated around the laser reflection point A by the rotating mechanism 4 while being reflected by the laser beam Bb to irradiate the inner surface of the pipe as a laser beam Bb, thereby rotating the laser beam Bb in the pipe circumferential direction at substantially the center of the pipe body. The coordinates on the pipe circumference are obtained for each constant rotation angle of the reflector, and the dimensions such as the inner diameter, the circumference, and the roundness are obtained by the arithmetic unit 20 from these coordinates. Also,
Lift-off adjustment mechanism 6 for adjusting the distance between the laser displacement meter and the reflector
It is possible to adjust the length of the lift-off in accordance with the pipe diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type dimension measuring device for measuring dimensions such as an inner diameter, a circumferential length and a roundness of a pipe such as a pipe.

[0002]

2. Description of the Related Art Conventionally, as a non-contact type device for measuring the inner diameter of a tubular body such as a steel pipe, for example, Japanese Patent Laid-Open No. 4-160303
The measuring device is equipped with a laser displacement meter mounted on an arm that can be inserted in the axial direction of the tube body, and the laser beam emitted from the laser displacement meter in the axial direction of the tube is armed. The light is refracted by 90 degrees in the radial direction by a prism or the like provided at the tip to irradiate the inner surface of the tube. When measuring the inner diameter, move the arm in the radial direction of the tube so that the surface to be measured is located within the measurable range of the laser displacement meter, and while rotating the tube, measure the inner surface and the laser displacement meter. Measure the distance between them to measure the inner diameter of the tube. In this case, the distance between the laser displacement meter and the prism is constant, and the slide mechanism for sliding the arm in the radial direction, for example, the vertical direction, in order to position the surface to be measured within the measurable range of the laser displacement meter. Is provided. In addition, in order to correspond to the inner diameter measurement of a large-diameter pipe,
Arms with the laser displacement meter and prism arranged and fixed as described above are provided in parallel with the tube axes, and a slide mechanism for adjusting the distance between the arms is provided on each arm, and the measured surface is It is designed to be within the measurable range.

[0003]

As described above, since the conventional apparatus measures while rotating the pipe, the deformation of the cross-sectional shape always appears in the same direction due to gravity when the pipe diameter becomes large, It loses its original tube shape. Therefore, the measurement error is large. In addition, the commercially available laser displacement meter has a limitation that the range that can be accurately measured is limited. Therefore, mechanically, each arm must be provided with a slide mechanism, which is complicated and expensive. There is.

However, recently, for example, a long lift-off of 1500 mm (commonly called the distance from the surface to be measured to the detector. Here, the change in distance of the surface to be measured around the irradiation point of the laser beam on the surface to be measured has the best accuracy. A laser displacement meter having an irradiation distance on the optical axis when determining a measurement range that can be measured by is developed and is being used in various fields.

Therefore, according to the present invention, by using the laser displacement meter having such a long lift-off, it is possible to accurately measure the dimensions such as the inner diameter, the peripheral length, the roundness, etc. from the small diameter pipe to the large diameter pipe with a simple mechanism. An object is to provide a measuring device.

[0006]

In order to achieve the above-mentioned object, the present invention comprises a support arm inserted inside a tubular body,
A tube body equipped with a laser displacement meter installed on the support arm for emitting a laser beam in the tube axis direction, and a reflector for reflecting the laser beam in the radial direction and irradiating the inner surface of the tube body. In the dimensional measurement apparatus, the laser displacement meter has a long lift-off equal to or larger than the radius of the tubular body, and is further provided with a rotating mechanism for rotating the reflector around a reflection point of the laser beam. is there.

In order to adjust the lift-off according to the diameter of the pipe, the distance between the laser displacement meter having a long lift-off and the reflector is relatively changed according to the diameter of the object to be measured, and the length of the lift-off is changed. A lift-off adjustment mechanism for keeping the height constant is provided.

Further, there is provided a size calculation device for calculating coordinates such as an inner diameter of the pipe body by obtaining coordinates on the circumference of the pipe for one rotation for each constant rotation angle of the reflector by the rotating mechanism.

[0009]

The principle of the dimension measurement of the tubular body according to the present invention will be explained with reference to FIG. 1. As shown in FIG. 1A, a laser displacement meter 2 having a lift-off larger than the radius of the tubular body 1 is installed in the central axis of the tubular body 1. A laser beam Ba is emitted from the laser displacement gauge 2 in the axial direction of the tube, and the laser beam Ba is reflected by the reflector 3 by 90 degrees to irradiate the inner surface of the tube body 1 as the laser beam Bb. The distance from the laser reflection point A of 3 to the measurement point P on the inner surface of the tube is measured. Here, when the reflector 3 is rotated about the laser reflection point A by the rotating mechanism 4, the laser beam Bb moves the laser reflection point A of the reflector 3 almost at the center of the tube 1 as shown in FIG. Since the laser beam Bb rotates about the center in the tube circumferential direction, the inner surface of the tube can be scanned by the laser beam Bb. The change in distance of the laser beam Bb at this time is collected as (ri, θi) coordinates of the measurement point Pi for each constant rotation angle of the reflector 3, and the circumference of the tubular body 1 is calculated based on these data for one rotation. Dimension, such as inner diameter, roundness, etc., is calculated by the dimension calculator.

A laser displacement meter 2, a reflector 3 and a tube body 1 are also provided.
The positional relationship with the inner surface of is adjusted in advance so that the distance change of the laser beam Bb when the reflector 3 is rotated is within the displacement measurement range of the laser displacement meter 2. That is, the distance between the laser displacement meter 2 and the reflector 3 is adjusted by the lift-off adjustment mechanism according to the diameter of the pipe to be measured, and the laser displacement meter 2 passes through the reflector 3 and reaches the inner surface of the tubular body 1 on the optical axis. Adjust the distance to match the desired liftoff length. Therefore, the measurement accuracy can be kept good.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing an outline of a pipe dimension measuring apparatus according to an embodiment of the present invention. As shown in the figure, a support arm 12 is provided on a support 11 on a base 10 so that the support arm 12 can be moved up and down by an elevating mechanism 13.
The reflector 3 and its accessory mechanism are installed. Further, the elevating mechanism 13 includes a ball screw 16 which is rotated by an elevating motor 15 installed on the support column 11 and which lifts the supporting base 1 of the supporting arm 12.
The lifting mechanism 13 can move the lifting table 14 and the support arm 12 in the vertical direction. The amount of vertical movement is detected by the encoder 17.

The above laser displacement meter 2 has a long lift-off which is equal to or larger than the radius of the tubular body 1. For example, the lift-off is 1500 mm and the measurement range is centered around the lift-off distance.
I use a 50 mm one. The laser displacement meter 2 is mounted on a movable table 5 which is slidable in the tube axis direction, and is moved in the tube axis direction by a lift-off adjusting mechanism 6. The lift-off adjustment mechanism 6 is a lifting mechanism 13
And a laser displacement meter 2 mounted thereon is moved in the tube axis direction by screwing a ball screw 8 rotated by a drive motor 7 into the moving table 5. You can The amount of movement is detected by the encoder 9. The guide mechanism of the moving table 5 is not shown, but can be a known means.

A reflector 3 installed facing the laser displacement meter 2 has a function of reflecting a laser beam emitted from the laser displacement meter 2 in the axial direction of the tube by 90 degrees in a radial direction. And so on. The reflector 3 is rotated about the reflection point A by the rotating mechanism 4, and the pulse generator 18 outputs a pulse signal at every constant rotation angle of the reflector 3 and every one rotation. . That is, the pulse generator 18 of the rotating mechanism 4 outputs a signal that generates one pulse each time the reflector 3 rotates 0.1 degree and a rotation angle signal of 2 bits in total that generates one pulse each rotation. , These signals are sent to the size calculator 20. The dimension calculation device 20 will be described later.

In this measuring apparatus, a support arm 12 is inserted into the tube body 1, a laser displacement meter 2 is adjusted by an elevating mechanism 13 so as to be located on substantially the central axis of the tube body 1, and a laser beam is also used. The position of the laser displacement meter 2 is adjusted by the lift-off adjustment mechanism 6 so that the sum La + Lb of the distances of Ba and Bb matches the lift-off length of the laser displacement meter 2. For example, when the measurement target is a small diameter tube, the laser displacement meter 2 is moved to the right side in FIG. 2, and the reflector 3 and the laser displacement meter 2 are moved.
A predetermined lift-off length is adjusted by increasing the distance La between and. In the case of a large diameter tube, the laser displacement meter 2 may be moved to the opposite left side. The positioning of the laser displacement meter 2 is performed by the control unit provided in the dimension calculation device 20.
It is automatically set according to the nominal diameter of. After a while,
A laser beam is emitted from the laser displacement meter 2 to start measurement.

The laser beam Ba emitted from the laser displacement meter 2 in the axial direction of the tube is reflected 90 degrees in the radial direction by the reflector 3 to become a laser beam Bb, which is applied to the inner surface of the tube 1. The laser beam Bb is reflected on the inner surface of the tubular body 1, and the reflected light is reflected again by the reflector 3 and received by the laser displacement meter 2, and the distance La of the laser beam Ba and the laser beam Bb are received.
The distance on the optical axis from the laser displacement meter 2 to the inner surface of the tubular body 1 is measured. Then, when the reflector 3 is rotated in the tube circumferential direction by the rotating mechanism 4, the laser beam Bb rotates in the tube circumferential direction of the tube body 1 around the reflection point A of the laser beam Ba at the reflector 3. From the pulse generator 18 of the rotating mechanism 4, a signal for generating one pulse for each rotation angle of 0.1 degree and a rotation angle signal of 2 bits in total for generating one pulse for each rotation are sent to the dimension calculation device 20. . The dimension calculation device 20 takes in the measurement signal of the laser displacement meter 2 each time the above-described rotation accuracy signal is input at every 0.1 degree, and performs the dimension calculation of the tubular body 1 every time the reflector 3 makes one rotation. .

Here, the internal configuration of the dimension calculation device 20 is as shown in FIG. In FIG. 3, 21 is a rotation angle interruption unit, 22 is a pulse counter, 23 is an interruption unit, 24 is an A / D conversion unit, 25 is a calculation unit, 26 is a setting unit, 27 is a control unit, and 28 is an output unit. . A signal of one pulse is input to the rotation angle interruption unit 21 from the pulse generator 18 of the rotation mechanism 4 every time the reflector 3 rotates by 0.1 degree, and the count value of the pulse counter 22 and the A / D ratio are input by this pulse signal. The calculation value of the laser displacement meter 2 of the conversion unit 24 is read by the calculation unit 25 and stored as coordinate data (r, θ) on the coordinate system having the laser reflection point A of the reflector 3 as the origin. This is repeated until the interrupt pulse signal is input from the pulse transmitter 18 to the interrupt unit 23, the reflector 3 makes one rotation, and the next interrupt pulse signal is input. When the interrupt pulse signal is input to the interrupt unit 23, the arithmetic unit 25 initializes the pulse counter 22 to perform moving average processing of the coordinate data for the rotation angle of 0 to 360 degrees of the reflector 3, that is, for one rotation. Then, the inner circumference length calculation, the inner diameter calculation, and the roundness calculation of the tube body 1 are performed. The nominal diameter of the tubular body 1 to be dimension-measured is input to the setting unit 26 from the outside by a keyboard, for example, and this value is sent to the calculation unit 25 and the control unit 27. The control unit 27 outputs a drive command to the drive motor 7 for positioning the laser displacement meter 2 based on the nominal diameter information of the tubular body 1, and the reflection point A of the reflector 3 is located substantially at the center of the tubular body 1. A height adjustment command is output to the lifting motor 15. The dimension calculation result of the calculation unit 25 is sent to the output unit 28 and output to the recorder or printer.

In the above embodiments, the tube has not been rotated. Therefore, the rotating laser beam Bb is blocked by the support arm 12, and a part of the inner surface of the tube where measurement cannot be performed occurs. However, by minimizing the angle at which the laser beam Bb is blocked in the structural design of the support arm 12, it does not matter if the inner diameter of the tubular body does not change suddenly. It is also possible to slightly rotate the tubular body to cover the non-measurable region. Further, the present invention can be applied to a rotating pipe even if the cross-section is deformed by gravity. For example, the welded pipe is gently rotating in a spiral shape, and the inner diameter of the pipe end can be measured by this measuring device in a short time.

[0018]

As described above, according to the present invention, a laser displacement meter having a long lift-off equal to or larger than the radius of the tube is used, and a laser beam emitted from the laser displacement meter in the tube axis direction is reflected by a reflector in the radial direction. Moreover, since the reflector is rotated around the laser reflection point by the rotating mechanism, the inner surface of the tube can be scanned in the tube circumferential direction by the laser beam rotating near the center of the tube. , Simple and accurate measurement data can be obtained.

Since the distance between the laser displacement meter and the reflector can be adjusted by the lift-off adjusting mechanism, it is possible to easily cope with small-diameter pipes to large-diameter pipes. Further, since the distance on the optical axis of the laser beam can be adjusted to a predetermined lift-off length by this lift-off adjustment mechanism, high measurement accuracy can be obtained regardless of the tube aperture.

Since the coordinates on the pipe circumference are obtained for each constant rotation angle of the reflector, the measured value distribution corresponds to the actual shape of the inner surface of the pipe, and the measured value distribution is used to determine the inner diameter, the circumference, and the true circle. It is possible to accurately calculate dimensions such as degrees.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of dimension measurement according to the present invention.

FIG. 2 is a schematic diagram showing an embodiment of the present invention.

FIG. 3 is a functional block diagram of the dimension calculation device in FIG.

[Explanation of symbols]

 1 Tube 2 Laser Displacement Meter 3 Reflector 4 Rotation Mechanism 6 Lift-off Adjustment Mechanism 12 Support Arm 13 Lifting Mechanism 20 Dimension Calculator

Claims (3)

[Claims] 1. A support arm inserted into the inside of the tubular body,
A tube body equipped with a laser displacement meter installed on the support arm for emitting a laser beam in the tube axis direction, and a reflector for reflecting the laser beam in the radial direction and irradiating the inner surface of the tube body. The laser displacement meter has a long lift-off equal to or larger than the radius of the tubular body, and further comprises a rotating mechanism for rotating the reflector about a reflection point of the laser beam. Measuring device. 2. A lift-off adjusting mechanism is provided, which relatively changes the distance between the laser displacement meter having the long lift-off and the reflector according to the diameter of the object to be measured, and keeps the lift-off length constant. The pipe size measuring apparatus according to claim 1. 3. A dimension calculation device for calculating a dimension such as an inner diameter of the pipe body by obtaining coordinates on the circumference of the pipe for one rotation for each constant rotation angle of the reflector by the rotating mechanism. The dimensional measurement device for a pipe according to claim 1.