JPH0749953B2 - U-tube size measuring method and device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for measuring the size of a curved pipe portion of a U-shaped pipe.

[Conventional technology]

U-shaped tubes are used in heat exchangers of plants such as nuclear power plants and thermal power plants. In this U-shaped pipe, there is a problem that the pipe is stressed by the bending strain generated when the pipe is processed into a U-shape and the cross-sectional shape is deformed. It is required to control the quality of products by measuring the outer surface curvature of the curved portion with high accuracy.

As a conventional method and apparatus for measuring outer diameter and roundness, there is a method using a linear gauge 8 as shown in FIG. FIG. 13 is a schematic diagram showing a method for measuring the outer diameter and roundness of the U-shaped tube 7 by the linear gauge 8. The measurement with the linear gauge 8 is to measure the outer diameter of the U-shaped tube 7 by sandwiching the flat U-shaped tube 7 with two holding members (not shown) and measuring the distance between the holding members. Yes, U
The horizontal and vertical outer diameters of the character tube 7 are measured. The linear gauge 8 is provided so as to be rotatable around the turning center O along the curved portion of the U-shaped tube 7 in the direction indicated by the arrow in the drawing.

The operator measures the outer diameters of the U-shaped pipe 7 in the horizontal direction and the vertical direction by the linear gauge 8 as described above by continuously rotating the linear gauge 8 in the arrow direction.

The roundness of the U-shaped tube 7 is as follows (1) from the measurement result of this outer diameter.
It is obtained as shown in the formula.

The outer surface curvature of the U-shaped tube was measured by an operator using an R gauge.

[Problems to be Solved by the Invention]

In the measurement with the linear gauge 8 as described above, the swivel center O of the measuring device has a slight deviation from the bending center of the U-shaped tube 7, so that in the horizontal measurement, the gripping direction of the gripping member. Is deviated from the direction of the axial cross section of the U-shaped tube 7, and thus an error occurs in the measured value, and also when the holding member of the linear gauge 8 is worn, the measured value also has an error. Further, the U-shaped tube may be damaged due to the contact between the holding member and the U-shaped tube 7.

Further, regarding the calculation of the roundness, since the roundness is calculated only by the measurement results in the two directions, that is, the horizontal direction and the vertical direction, if the roundness is defective in the directions other than the two directions, It was undetectable.

Since the outer surface curvature is measured by an operator using an R gauge, there is a problem that there are individual differences in measurement, measurement accuracy is poor, and reproducibility is poor.

The present invention has been made in view of the above circumstances, and uses a non-contact type distance detector to measure the outer diameter while rotating the distance detector along the curved portion of the U-shaped tube. Provided are a U-shaped tube dimension measuring method and apparatus capable of measuring various dimensions of the U-shaped tube with high accuracy by correcting based on a deviation amount of a turning center with respect to a bending center of the U-shaped tube. The purpose is to

[Means for Solving the Problems]

A dimension measuring method of a U-shaped tube according to the present invention is a U-shaped tube for measuring various dimensions of a curved section of the U-shaped tube by rotating a non-contact type distance detector along the curved section of the U-shaped tube. In the dimension measuring method, the deviation amount of the turning center of the distance detector with respect to the bending center of the U-shaped tube is obtained, and the measurement result is corrected by the deviation amount.

The U-shaped tube dimension measuring device according to the present invention is a U-shaped tube dimension measuring apparatus for measuring various dimensions of a curved portion of the U-shaped tube by a non-contact type distance detector. Turning means for turning the distance detector along the section, turning means for turning the distance detector around the tube axis of the U-shaped tube, and the U-shaped tube based on the measurement results obtained by using these means. And a computing unit that corrects the measurement result based on the deviation amount of the turning center of the turning unit with respect to the bending center.

[Action]

According to the first aspect of the present invention, when measuring various dimensions of the curved portion of the U-shaped tube, the deviation amount of the turning center of the distance detector with respect to the bending center of the U-shaped tube is measured from the turning center. The distance to the pipe axis of is measured at a plurality of points in the curved portion, the position of the bending center is obtained from these measurement results, and the deflection center of the swivel center with respect to the bending center of the U-shaped pipe obtained by
The measurement result that should suppress the measurement error caused by the deviation amount is corrected.

Further, according to claim 2 of the present invention, the outer diameter of the U-shaped pipe can be measured from multiple directions by rotating the distance detector about the tube axis by the rotating means.
By swiveling along the curved portion of the U-shaped pipe, it is possible to measure at an appropriate length pitch over the entire length of the curved portion. By obtaining the deviation amount and correcting the measurement result by geometric calculation, the error in the measurement result due to the deviation amount is reduced.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the drawings illustrating the embodiments. FIG. 1 is a schematic plan view showing a principle of a dimension measuring method of a U-shaped tube according to the present invention in which a U-shaped tube is laid flat, and FIG. It is the side view seen from the pipe axis direction of the character tube 7.

In the figure, 10 is a light emitter 10 that emits light having a linear irradiation range.
1 and a light receiver 102 formed by arranging linear diode arrays (not shown) in parallel with each other so as to oppose the irradiation range of the light emitter 101 and the juxtaposed range of the linear diode array which is the light reception range of the light receiver 102. The distance detector is provided, and the object to be measured is positioned so as to intersect the irradiation range between them, and the distance (width) of the shadow projected by the object to be measured on the light receiver 102 is detected. . The distance detector 10 is designed to horizontally swing around the turning center O ₁ along the curved portion of the U-shaped tube 7 placed flat in a non-contact state with the U-shaped tube 7. The turning center O ₁ is arranged so as to coincide with the bending center O ₂ of the U-shaped tube 7.

To measure the outer diameter of the U-shaped tube 7 by the distance detector 10, the distance detector 10 is arranged such that the light emitter 101 and the light receiver 102 face each other in the vertical direction. The turning is performed at a plurality of curved portions of the U-shaped pipe 7.

Next, a method of measuring the outer diameter of the U-shaped tube 7 by the distance detector 10 will be described. In FIG. 2, the distance detector 10 is a light emitter 10.
It is provided so that the direction in which 1 and the light receiver 102 face each other is the vertical direction, and light is emitted from the light emitter 101 toward the light receiver 102. Further, the distance detector 10 is provided so as not to contact the curved portion of the U-shaped tube 7. The light emitted from the light emitter 101 is partially blocked by the U-shaped tube 7 located between the light emitter 101 and the light receiver 102, and is received by the light receiver 102. In the light receiver 102, the outer diameter of the U-shaped tube 7 can be obtained by detecting the radial projection distance D _n of the U-shaped tube 7 on the light receiving surface.

When the outer diameter of the U-shaped pipe 7 is measured by such a distance detector 10, the turning center O _{1 with} respect to the bending center O ₂ of the U-shaped pipe 7 is measured.
Deviation causes a measurement error. In the present invention a method to eliminate the measurement errors, bent to detect the position of the center O _2, obtains a deviation amount with respect to the turning center O ₁ of the bending center O _2, the outer diameter on the basis of the result Correct the measured value.

Next, a method of correcting the outer diameter will be described. In the figure
E _n is the edge length from the outermost end of the light receiver 102 at the position farthest from the turning center O ₁ in the distance detector 10 to the projected end of the U-shaped tube 7, and R ₀ is the turning center O ₁ from the above. Receiver 102
It is the length to the end of.

Using the above parameters, the U-shaped tube 7 from the turning center O ₁
The length R _n to the tube axis is calculated by the following equation (2).

Considering a coordinate system with the turning center O ₁ as the origin, the direction in which the straight pipe portion of the U-shaped pipe 7 extends is the x-axis, and the direction orthogonal to the x-axis at the origin is the y-axis, the coordinates are If the angle at which the line segment connecting the above measurement point and O ₁ intersects the y-axis is θ _n , the coordinates of the measurement point by the detector 10 represented by R _n and θ _n are as follows (3), It becomes x _n , y _n shown in the equation (4).

x _n = R _n × sin θ _n (3) y _n = R _n × cos θ _n (4) FIG. 3 is a diagram showing a method of calculating the bending center O ₂ of the curved portion of the U-shaped pipe 7. The middle P _{1 to} P ₉ are obtained by measuring E _n and D _n of the curved portion of the U-shaped tube 7 at, for example, 9 points, and based on the results, coordinated by the method as described above.

These select any three measurement points from the measurement point P ₁ to P _9, form a triangle connecting these three measurement points. In this way, N triangles obtained by combining arbitrary 3 measurement points are formed, and the center point (X _N , Y) of the circle circumscribing these triangles is formed.
_N ) ie the bending center O ₂ is calculated for each triangle.
Since there are variations in the _N (X _N , Y _N ) data obtained as a result, these are averaged as in the following equation (5). The calculation results δ _x and δ _y are the deviation amounts of the bending center O ₂ with respect to the turning center O _{1 in} the x-axis direction and the y-axis direction. In other words, δ _x and δ _y are the coordinates of the bending center O ₂ in the x, y coordinate system.

When the displacement amounts δ _x and δ _y are obtained in this way, the displacement center δ _x and δ _y can be measured from the bending center O ₂ at any measurement point of the U-shaped pipe 7 and the turning center. The measurement angle deviation α from the case of measurement from O ₁ is obtained.

FIG. 4 is a diagram showing a method for correcting the outer diameter. In the figure, 71 is the outer circumference of the axial cross section of the curved portion of the U-shaped pipe 7 at any place, and 72
Is a distance detector having a turning center O ₁ as described above.
With 10, the origin of the axis O ₄ of the U-shaped tube 7 is the x ′ axis which is the direction toward the bending center O ₂ and the y ′ axis which is the direction orthogonal to this, and the x ′, y ′ coordinate system. With respect to the rotation center O ₃ which has a displacement amount of X ′ in the x ′ axis direction and Y ′ in the y ′ axis direction.
It is the outer circumference of the U-shaped pipe 7 measured around it.

When the outer diameter is measured by irradiating the distance detector 10 with respect to the x ′ axis by the angle θ ₁ and irradiating light from the direction indicated by the white arrow in the figure, the light receiver 102 having the light receiving width W is used. The outer diameter measured by the deviation of the bending center from the turning center O ₁
The projected distances D and _N are points F and G at both ends in the direction in which the linear diode array of the light receiver 102 extends. The measured value is the deviation amount of the bending center O ₂ with respect to the turning center O ₁ . The error caused is included. Therefore, the measured value of the outer diameter is corrected and calculated using the deviation amount.

This correction method is shown below. First, the deviation amount RG of the rotation center O _{3 with} respect to the axial center O ₄ of the U-shaped tube 7 is determined by the X ′, Y ′ and θ ₁
Is calculated using the following equation (6).

R _G = (X ′ _X tan θ ₁ + Y ′) × cos θ ₁ (6) Next, the length A from the rotation center O ₃ to one end of the light receiving surface of the distance detector 10 and the edge length _En Using the deviation amount R _G , the length R _L from the axis O ₄ to the point F is calculated by the following equation (7).

R _L = (A−E _n −R _G ) / cos θ ₄ (7) where θ ₄ is a line connecting the straight line parallel to the light receiving surface of the light receiver 102 from the F point and the axis O ₄ to the F point. And the angle formed by the line segment connecting point F and O ₄ with the y ′ axis is θ
_Set to ₃ . Further, an intersection of a line parallel to the x ′ axis extending from the point F toward the outer circumference 71 and the axial cross section 71 is defined as a point H. The length RD ₁ between the axis O ₄ and the point H is the radius of the U-shaped tube 7 that does not include an error due to the deviation amount between the turning center O ₁ and the bending center O ₂ , and similarly to the above G The length RD ₂ between the intersection I and the axis O ₄ of the line 71 parallel to the x ′ axis extending from the point to the outer circumference 71 and the outer circumference 71 is obtained, and the above RD ₁ is added to this to correct the length. The outer diameter DD is required.

If the angle formed by the RD ₁ and the y ′ axis is θ ₂ , then RD ₁ is obtained by the following equation (8).

RD ₁ = R _L × cos θ ₃ / cos θ ₂ (8) Further, RD ₂ is obtained in the same manner as RD _1, and since RD ₁ and RD ₂ are radii respectively, the corrected outer diameter DD is (9) below. It is calculated as the sum of RD ₁ and RD ₂ as shown in the equation.

DD = RD ₁ + RD ₂ (9) The above method is the outer diameter correction method.
_{When 1} is θ ₁ = 0 ° (when the direction in which the light emitter 101 and the light receiver 102 of the distance detector 10 face each other is horizontal), the measured value D _n is taken as the measured value of the outer diameter. In the case of 0 ° <θ ₁ <90 °, the corrected outer diameter is used as the measured value, and θ
= 90 ° (when the light emitting device 101 and the light receiving device 102 of the distance detector 10 face each other in the vertical direction), as shown in FIG.
Using the measurement angle deviation α caused by the deviation amount between the turning center O ₁ and the bending center O ₂ , D _n × 1 / cos α is taken as the measured value of the outer diameter.

The roundness is measured at a predetermined position around the pipe axis of the U-shaped pipe 7, and the maximum value DD _MAX and the minimum value DD are calculated from the outer diameter value DD corrected as described above.
Calculate _{MIN according} to the following equation (10).

Next, a method of calculating the outer surface curvature will be described. FIG. 5 is a diagram showing a method for obtaining the outer surface curvature. From the rotation center O ₃ outer surface Q ₁ ~
R up to Q ₅ as a function of detector 10 rotation angle θ ₁
It is expressed by (θ ₁ ), which allows Q _{1 with} respect to the rotation center O ₃
The coordinates (X, Y) of ~ Q ₅ are calculated by the following equation (11).

X = R (θ ₁ ) sin θ ₁ , Y = R (θ ₁ ) cos θ ₁ (11) Of the (X, Y) coordinates thus obtained, any 3
Select points to form a triangle S. In this way, the radius RR of the circle circumscribing the N triangles obtained by combining any three measurement points is calculated, and the average value of the radius RR is given in (12) below.
It is calculated according to the formula, and as a result, the outer surface curvature within the range of the rotation angle θ ₁ is obtained.

However, N: number of triangles Next, the configuration of an apparatus for realizing the dimension measurement of the U-shaped tube according to the above-described principle will be described.

FIG. 6 is a front view of a U-shaped tube dimension measuring device according to the present invention, and FIG. 7 is a side view thereof. The dimension measuring device of the U-shaped tube is a box-shaped base 3 provided with wheels 31, 31, 31, 31 for moving the device and pedestals 32, 32, 32, 32 for fixing on the lower surface, and the base. U-tube fixing portion 4 which is disposed on the upper surface of U-tube 3 and horizontally mounts and fixes the U-tube 7, and in the same manner as the U-shaped tube fixing portion 4 on the upper surface of the base 3. A measuring unit 1 which is disposed and moves along the curved portion of the U-shaped tube 7 fixed as described above and automatically measures the outer diameter of the curved portion by a distance detector 10 using light. To be done.

The U-shaped tube fixing part 4 has a columnar shape standing on the base 3 and a support plate 44 for supporting the U-shaped tube 7 on the upper ends of the columns 41, and the measuring part 1 is arranged in the longitudinal direction thereof. It is installed so that it faces in the direction indicated. At both ends of the support plate 44 in the longitudinal direction, in order to mount and fix the U-shaped tube 7 so that the bending direction of the U-shaped tube 7 is horizontal to the upper surface of the base 3, the U-shaped tube 7 is opposed to each other. A pipe holder 45 for holding the U-shaped pipe 7 from above and below by the tightening force of the screw 43 for holding the pipe holding members 42, 42 each having a groove with an arcuate cross-section for inserting the both straight pipe portions of the U-shaped pipe 7. , 45 is U
The character tube 7 is arranged so that the direction in which the straight tube portion extends extends toward the measuring unit 1 and is fixed.

In the U-shaped pipe fixing portion 4, the pipe holders 45, 45 are provided.
Thus, the inspection U-shaped tube 7 is fixed so that the curved portion of the U-shaped tube 7 faces the measuring section 1.

Next, the configuration of the measuring unit 1 will be described. Reference numeral 17 denotes a support base that supports the main components of the measuring unit 1 such as the detector turning motor 16 and the distance detector 10. The support 17 is attached to the upper surface of the base 3, and a slide bearing is used on the upper surface of the base 3, and the feed handle 151 is adjusted to adjust the U-shaped tube 7 to the upper surface of the base 3. A first slide base 15 which slides in the pipe axis direction of the straight pipe portion is provided. Similarly, a slight bearing is used on the first slide base 15, and the first slide base 15 is adjusted by adjusting the feed handle 141.
Second slide base 14 that slides in a direction orthogonal to the sliding direction of
Is provided.

The second slide base 14 is provided with a circular hole for mounting a turning motor 16 described later, and the turning motor 16 is horizontally mounted on the upper surfaces of the first slide base 15 and the support base 17. A hole having a larger diameter than this circular hole is opened so that the hole can be moved to.

In the circular hole of the second slide base 14, the detector turning motor 16 is arranged so that the rotary shaft 161 of the detector turning motor 16 is vertically positioned.
It is attached by penetrating the upper surfaces of the slide base 15 and the support base 17. An end of a turning arm 12 for turning the distance detector 10 in a horizontal direction is attached to a rotation shaft 161 of the detector turning motor 16 so as to be horizontally turnable. That is, the first slide base 15 and the second slide base 14 adjust the position of the rotary shaft 161 which is the rotary shaft of the rotary arm 12.

The revolving arm 12 is positioned above the support arm 122 attached to the rotation shaft 161, and a slide bearing is used so that the revolving arm 12 can slide in the revolving radius direction of the support arm 122. The slide arm 121 provided and the slide arm 12 with respect to the support arm 122
The slide position adjusting member 123 is attached to the slide arm 121 to adjust the relative position of 1 and fixes the slide arm 121 to the support arm 122 by screwing the screw 124.
The turning radius of the turning arm 12 can be adjusted by the slide position adjusting member 123.

Further, a lower part of a detector mounting plate 111 for mounting the distance detector 10 is attached to a side surface of an end portion of the slide arm 121 on the side opposite to the side where the rotating arm 161 is attached, of the revolving arm 12. On one surface of the upper portion of the detector mounting plate 111, the distance detector 10 is attached at a position facing the U-shaped tube 7 attached to the U-shaped tube fixing portion 4 as described above.

The distance detector 10 has an external appearance such that a groove 103 having a U-shaped cross section is formed so as to penetrate from one surface to an opposite surface of the rectangular parallelepiped, and the light emitter 101 is provided on one surface of the opposed surface of the groove 103.
And a light receiver 102 on the other surface, and the groove portion 1
Position the curved part of the U-shaped tube 7 at 03, and aim at the light emitter 10
The light is emitted from 1, the light is received by the light receiver 102, and the outer diameter of the tube is measured by detecting the length of the shadow generated on the light receiving surface of the light receiver 102 when the light is blocked by the tube.

The distance detector 10 is provided with a mounting member 114 having a U-shaped cutout at the center on one of both side surfaces having the groove 103, and the mounting member 114 is opposite to the surface mounted on the distance detector 10. A gear 113 having a cutout portion similar to this is mounted on the surface. Further, a guide ring 112 having a discontinuous portion in the width dimension of the U-shaped notch is attached to the surface of the gear 113 opposite to the surface on which the attachment member 114 is attached.

The mounting member 114, the gear 113, and the guide ring 112 are mounted so that their respective cutouts communicate with the groove 103 of the distance detector 10. And the guide ring 112
The surface opposite to the surface on which the gear 113 is attached is attached to the detector attachment plate 111. On the detector mounting plate 111, the detector rotating motor 11 that drives the gear 113 is mounted on the surface opposite to the surface on which the guide ring 112 is mounted. A small gear (not shown) that meshes with the gear 113 is attached to the rotation shaft of the detector rotation motor 11, and the gear 113 is rotated by the rotation of the rotation shaft to move the distance detector 10 around the rotation center of the gear 113. It is designed to be rotated. That is, when the curved portion of the U-shaped pipe 7 is positioned in the groove 103 of the detector 10, the distance detector 10 is provided around this pipe axis.
Rotates.

At the time of measurement by the U-shaped tube dimension measuring device configured as described above, the U-shaped tube 7 is fixed to the U-shaped tube fixing portion 4 such that its curved portion enters the groove 103 of the distance detector 10, Next, the first slide base 14 and the second slide base 15 of the measuring unit 1 adjust the turning center of the distance detector 10 so as to be substantially equal to the bending center of the U-shaped pipe 7, and the slide position adjusting member 123 detects the distance. The turning radius of the device 10 is adjusted so that the distance detector 10 can turn along the curved portion of the U-shaped tube 7 in a non-contact state. Then, the detection angle is changed by changing the rotation state of the distance detector 10 by driving the detector rotating motor 11, and the distance detector 10 is moved by the driving of the detector rotating motor 16 to bend the U-shaped tube 7. Distance detector while turning along
Measure the U-tube 7 by 10.

FIG. 8 is a block diagram regarding the measurement when the measurement is performed using the above-described U-shaped tube dimension measuring device. In the figure, 5 is a measurement control unit for controlling the drive of the detector turning motor 11 and the detector turning motor 16, and 6 is a data processing unit for processing the measured data. 53 is a sequencer in which a sequence is set in which the distance detector 10 is moved by driving the detector rotation motor 11 and the detection rotation motor 16 in the measurement procedure by the distance detector 10, that is, in the dimension measurement. The output terminal is connected to the input terminal of the measurement controller 50 that controls the turning motor driving device 51 and the turning motor driving device 52.

The measurement controller 50 sequentially reads the measurement procedure from the sequencer 53 and outputs a control signal to the turning motor drive device 51 and the turning motor drive device 52 to move the distance detector 10 according to the measurement procedure. The turning motor driving device 51 and the turning motor driving device 52 perform drive control of the detector turning motor 11 and the detector turning motor 16 based on the input control signal.

In the data processing unit 6, the input side terminal of the correction arithmetic unit 60 is connected to the output side terminal of the receiver 102,
The measurement data detected by the receiver 102 is input to the correction calculation device 60. The correction calculation device 60 corrects the input measurement data to calculate the outer diameter, further calculates the outer surface curvature and the circularity, and outputs the calculation result to the printer and the X-axis.
The data is output to an output device 61 such as a Y plotter, and similarly to a storage device 62 such as a floppy disk.

Next, the overall work procedure in the case of actually measuring the dimensions of the U-shaped pipe 7 using the apparatus having the above-described configuration will be described based on the flowchart shown in FIG.

First, a predetermined number of measurement points on the curved portion of the U-shaped tube 7 are determined. Then, the outer diameter of one place is measured around the pipe axis at a predetermined pitch over the entire circumference, and when this is completed, the outer diameter is moved along the curved portion of the U-shaped pipe 7 and the same outer diameter is measured. This measurement is U
The measurement is completed over the entire curved portion of the character tube 7 (step 1).

Subsequently, based on the data obtained by the measurement in the correction calculation device 60, as described above, the length R _n from the turning center O ₁ to the tube axis and the turning angle θ _n determine the bending center O of the U-shaped tube. The coordinates of ₂ are calculated (step 2).

Next, the deviation amounts δx, δy on the coordinates of the bending center O ₂ and the turning center O ₁ calculated in step 2 and the measurement angle deviation α are calculated (step 3), and the deviation amounts δx, δy and The measured value of the outer diameter is corrected and calculated based on the measured angle deviation α (step 4).

Then, the maximum value and the minimum value of the outer diameter value corrected in step 4 are obtained, and the roundness is calculated (step 5).

Further, in step 6, as described above, the outer surface curvature of the tube axis cross section is calculated based on the measurement result of the distance from the rotation center O ₃ of the detector on the circumference of each measurement point (step 6).
The results of the above measurement and calculation are output to the output device 61 and the storage device 62, and the measurement work is completed.

Hereinafter, as described above, the calculation methods will be individually described according to the flowcharts showing the procedure.

FIG. 10 is a flowchart showing the procedure for calculating the deviation amount of the bending center O ₂ with respect to the turning center O ₁ , and in step 1, the distance detector 10 measures each part of the U-shaped pipe. From these measurement results, the edge length En, the outer diameter Dn, and the
Parameters such as the length R ₀ up to the tip of 102 are calculated (step 2).

Next, the length Rn from the turning center O ₁ to the pipe axis of the U-shaped pipe 7 is calculated from the above parameters, and x, y coordinates of each measurement point of the curved portion of the U-shaped pipe 7 are calculated from the Rn ( Step 3). Then, the average value of the center points of the circumscribed circles of the triangles connecting these measurement points is calculated, and the calculation result is set as the bending center O ₂ of the U-shaped pipe 7 (step 4). After the above calculation is executed, each calculation result is output to the output device 61 and the storage device 62. (Step 5).

FIG. 11 is a flow chart showing the procedure for correcting the outer diameter and calculating the roundness. In the correction calculation device 60, the measurement result as described above is read from the memory (step 1), and the displacement amount RG of the axial center O ₄ of the tube and the rotation center O ₃ of the detector 10 at each measurement point is calculated ( Step 2).

Then, from the deviation amount RG, the edge length En, and the length A from the rotation center O ₃ to the light receiving end of the light receiver 102, the radius of the tube RD ₁ which does not include the error from the axis O ₄ , RD ₂ are calculated (step 3), these radii are added, and the corrected outer diameter value DD is calculated (step 4).

Next, the maximum and minimum values (DD _MAX , DD _MIN ) are extracted from the corrected outer diameter value DD calculated in step 4 (step 5), and the difference is divided by the nominal outer diameter to determine the roundness. Calculate (step 6). The above calculation results are output to the output device 61 and the storage device 62 (step 7).

FIG. 12 is a flowchart showing the procedure for calculating the outer surface curvature of the circumferential portion of the axial section of the U-shaped pipe 7. In the correction arithmetic unit 60, the above-mentioned measurement results are read from the memory (step 1), and the measurement points on the circumference are coordinated with the rotation center O ₃ as the origin (step 2).

Next, the radius RR of the circumscribed circle of the triangle connecting the coordinated measurement points
Is calculated arbitrarily (step 3), and these radii ▲ ▼
Are averaged to calculate the outer surface curvature RR (step 4). The above calculation results are output to the output device 61 and the storage device 62 (step 5).

Using the method and apparatus of the present invention as described above, the actual
As a result of measuring the outer diameter of a U-shaped pipe having a radius of 22.23 mm, a roundness of 6% or less, and an outer surface curvature of 8.0 mm or less, a measurement error of ± 0.05 mm or more occurred in the conventional device, but the measurement was performed by the method and device of the present invention. As a result, the measurement error was suppressed to ± 0.03 mm or less.

〔effect〕

As described above in detail, in the present invention, a non-contact type distance detector is used, and the outer diameter is measured while turning the same along the curved portion of the U-shaped pipe. The present invention has an excellent effect such that it is possible to measure various dimensions of the curved portion of the U-shaped tube with high accuracy by correcting the position based on the deviation amount of the turning center from the bending center.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing the principle of a U-shaped tube dimension measuring method according to the present invention, FIG. 2 is a side view of a non-contact type distance detector, and FIG. 3 is a bending center of the U-shaped tube. Figure showing the calculation method of
FIG. 4 is a diagram showing a method for correcting the outer diameter, FIG. 5 is a diagram showing a method for obtaining the outer surface curvature, FIG. 6 is a front view of a U-shaped tube dimension measuring device, FIG. 7 is a side view thereof, and FIG. FIG. 8 is a block diagram thereof, FIG. 9 is a flow chart of the entire work procedure when measuring the dimensions of the U-shaped pipe 7, and FIG. 10 is a flow chart of the procedure of calculating the deviation amount of the bending center with respect to the turning center. Figure is a flow chart showing the procedure for correcting the outer diameter and calculating the roundness. Figure 12 is a flow chart showing the procedure for calculating the outer surface curvature of the circumference of the axial cross section of the U-shaped tube. Figure 13 is the conventional linear It is a figure which shows the measuring method of the outer diameter and roundness of a U-shaped pipe by a gauge. 1 ... Measuring part, 4 ... U-tube fixed part, 7 ... U-tube 10 ... Distance detector, 11 ... Detector rotation motor 16 ... Detector rotation motor, 60 ... Correction calculation device

Claims (2)

[Claims] 1. A dimension measuring method for a U-shaped pipe, wherein a non-contact type distance detector is swung along a curved portion of the U-shaped tube to measure various dimensions of the curved portion of the U-shaped tube. A dimension measuring method for a U-shaped tube, comprising: obtaining a deviation amount of a turning center of a distance detector with respect to a bending center of the character tube, and correcting a measurement result by the deviation amount. 2. A U-shaped tube dimension measuring device for measuring various dimensions of a curved portion of a U-shaped tube by a non-contact type distance detector, wherein the distance detector is swung along the curved portion of the U-shaped tube. Turning means for turning, a turning means for turning the distance detector around the tube axis of the U-tube, and a turning center of the turning means with respect to the bending center of the U-tube from the measurement results obtained by using these means. And a calculation means for correcting the measurement result based on the deviation amount by geometrical calculation, and a U-shaped tube dimension measuring device.