Calibration device and outer diameter measurement method

Abstract

To provide an external diameter measurement device that can associate a measured external diameter about a different radial direction with an axial direction position of a measured body.SOLUTION: An external diameter measurement device 100 comprises: first laser type external diameter meters 1 and 2 for detecting an either end position in a horizontal direction of a measured body P; second laser type external diameter meters 3 and 4 for detecting an either end position in a vertical direction of the measured body; first drive means 5 and 6 that adjust a space distance of the first laser type external diameter meter; second drive means 7 and 8 that adjust a space distance of the second laser type external diameter meter; a velocity sensor 9 that measures a conveyance velocity of the measured body; and computation means 10 that computes an external diameter of the measured body. The computation means is configured to compute an external diameter in the horizontal direction of the measured body on the basis of the either end position in the horizontal direction of the measured body, and compute an external diameter in the vertical direction of the measured body on the basis of the either end position of the measured body, and associate the external diameter in the horizontal direction of the measured body with the axial direction position of the measured body on the basis of the conveyance velocity of the measured body.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a calibration device used for calibrating an outer diameter measuring device that measures the outer diameter of a long object to be measured having a substantially circular cross-section with an outer diameter of 300 mm or more, such as a large-diameter forged pipe, and is axially conveyed, Outer and a method for measuring the outer diameter of an object to be measured using the outer diameter measuring device and the calibration device.

Background Art

[0002] Conventionally, for large-diameter forged pipes with an outer diameter of 300 to 900 mm, it is common for an operator to manually measure the outer diameter using a measuring instrument such as a large caliper in a stationary state. However, manual measurement using a measuring instrument has problems such as the possibility of individual differences among operators and the difficulty of measuring the entire quantity and entire length from the perspective of man-hours.

[0003] For this reason, for example, Patent Document 1 proposes an outer diameter measuring device for a large-diameter pipe using a laser type outer diameter gauge. According to the device described in Patent Document 1, since the outer diameter of a large-diameter pipe during conveyance can be continuously measured, it is possible to measure the entire quantity and entire length. Also, individual differences among operators do not occur.

[0004] However, Patent Document 1 does not disclose or suggest associating the outer diameters measured in different radial directions with the axial position of the large-diameter pipe. If the outer diameters measured in different radial directions are not associated with the axial position, it is not possible to accurately compare the outer diameters in different radial directions at the same axial position. Therefore, with the device described in Patent Document 1, for example, the ellipticity (=(maximum outer diameter - minimum outer diameter) / average outer diameter) cannot be accurately calculated. Furthermore, Patent Document 1 does not disclose or suggest a device for calibrating an outer diameter measuring device.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made to solve the problems of the prior art as described above, and is an apparatus for measuring the outer diameter of a long object to be measured having a substantially circular cross section with an outer diameter of 300 mm or more and being conveyed in the axial direction, and is capable of associating the outer diameters measured in different radial directions with the axial position of the object to be measured. An outer diameter measuring device is provided. 、 An object of the present invention is to provide a calibration device that is used for efficiently calibrating. Further, an object of the present invention is to provide a method for accurately measuring the outer diameter of an object to be measured using the outer diameter measuring device and the calibration device.

[0007] To solve the above problems, the present invention provides A calibration device used for calibrating an outer diameter measuring device, wherein the outer diameter measuring device is An apparatus for measuring the outer diameter of a long measurement object having an outer diameter of 300 mm or more and a substantially circular cross-section that is horizontally conveyed in the axial direction, the apparatus being arranged on both horizontal sides orthogonal to the conveyance direction of the measurement object sandwiching the measurement object, respectively, a pair of first laser type outer diameter gauges for detecting both horizontal end positions of the measurement object, and at positions spaced apart in the conveyance direction of the measurement object with respect to the pair of first laser type outer diameter gauges, arranged on both upper and lower sides sandwiching the measurement object, respectively, a pair of second laser type outer diameter gauges for detecting both upper and lower end positions of the measurement object, first driving means for adjusting the horizontal separation distance of the pair of first laser type outer diameter gauges, second driving means for adjusting the vertical separation distance of the pair of second laser type outer diameter gauges, a speed sensor for measuring the conveyance speed of the measurement object, and arithmetic means for calculating the outer diameter of the measurement object, the second driving means includes an arm to which the lower second laser type outer diameter gauge of the pair of second laser type outer diameter gauges is attached, the arm is stationary at a fixed position without moving in the vertical direction, and the arithmetic means calculates the horizontal outer diameter of the measurement object based on both horizontal end positions of the measurement object detected by the pair of first laser type outer diameter gauges whose horizontal separation distance is adjusted by the first driving means, and based on both upper and lower end positions of the measurement object detected by the pair of second laser type outer diameter gauges whose vertical separation distance is adjusted by the second driving means, calculates the vertical outer diameter of the measurement object, and associates the horizontal outer diameter and the vertical outer diameter of the measurement object with the axial position of the measurement object based on the conveyance speed of the measurement object measured by the speed sensor , the calibration device has a length corresponding to a separation distance in the transport direction of the object to be measured between the first laser type outer diameter gauge and the second laser type outer diameter gauge and extends horizontally, and when calibrating the outer diameter measuring device, a support body arranged such that its longitudinal direction coincides with the transport direction of the object to be measured, a first calibration bar detachably attached to one end of the support body, extending in a horizontal direction orthogonal to the longitudinal direction of the support body, and movable in a horizontal direction orthogonal to the longitudinal direction of the support body with respect to the support body, and a second calibration bar detachably attached to the other end of the support body, extending in the vertical direction, and movable in the vertical direction with respect to the support body, a calibration device is provided.

[0008] According to the present invention Calibrated with a calibration device Examples of the measurement object whose outer diameter is measured by the outer diameter measurement apparatus according to the present invention include large-diameter forged pipes having an outer diameter of 300 to 900 mm, but it is not necessarily limited thereto. As long as it is a long measurement object having an outer diameter of 300 mm or more and a substantially circular cross-section that is conveyed in the axial direction, it can be applied to various measurement objects such as pipes other than forged pipes and solid bars. According to the present invention Calibrated with a calibration deviceAccording to the outer diameter measuring device, both end positions of the object to be measured in the horizontal direction are detected by a pair of first laser-type outer diameter gauges, and the outer diameter of the object to be measured in the horizontal direction is calculated by the calculation means based on the detected both end positions of the object to be measured in the horizontal direction. Similarly, both end positions of the object to be measured in the vertical direction are detected by a pair of second laser-type outer diameter gauges, and the outer diameter of the object to be measured in the vertical direction is calculated by the calculation means based on the detected both end positions of the object to be measured in the vertical direction. Then, the calculation means associates the outer diameter of the object to be measured in the horizontal direction and the outer diameter of the object to be measured in the vertical direction with the axial position of the object to be measured based on the conveyance speed of the object to be measured measured by the speed sensor. Specifically, for example, after the tip (the end on the downstream side in the conveyance direction) of the object to be measured reaches the measurement position of the pair of first laser-type outer diameter gauges and both end positions of the object to be measured in the horizontal direction at the tip of the object to be measured start to be detected by the pair of first laser-type outer diameter gauges (after the calculation means starts calculating the outer diameter of the object to be measured in the horizontal direction), by multiplying the elapsed time by the conveyance speed of the object to be measured measured by the speed sensor, the axial position (distance from the tip) of the object to be measured at the elapsed time can be calculated. It is conceivable to associate the calculated axial position of the object to be measured with the outer diameter of the object to be measured in the horizontal direction calculated at the elapsed time. Similarly, after the tip of the object to be measured reaches the measurement position of the pair of second laser-type outer diameter gauges and both end positions of the object to be measured in the vertical direction at the tip of the object to be measured start to be detected by the pair of second laser-type outer diameter gauges (after the calculation means starts calculating the outer diameter of the object to be measured in the vertical direction), by multiplying the elapsed time by the conveyance speed of the object to be measured measured by the speed sensor, the axial position of the object to be measured at the elapsed time can be calculated. It is conceivable to associate the calculated axial position of the object to be measured with the outer diameter of the object to be measured in the vertical direction calculated at the elapsed time. As described above, according to the Calibrated with a calibration device outer diameter measuring device according to the present invention, it is possible to associate the outer diameters measured in different radial directions of the object to be measured, specifically, the outer diameter of the object to be measured in the horizontal direction and the outer diameter of the object to be measured in the vertical direction, with the axial position of the object to be measured.

[0009] Note that according to the present invention Calibrated with a calibration deviceAccording to the outer diameter measuring device, since it is provided with first driving means for adjusting the horizontal separation distance between a pair of first laser type outer diameter gauges and second driving means for adjusting the vertical separation distance between a pair of second laser type outer diameter gauges, it is possible to detect the horizontal end positions of the object to be measured with a pair of first laser type outer diameter gauges and detect the vertical end positions of the object to be measured with a pair of second laser type outer diameter gauges. Accordingly, it is possible to adjust the horizontal separation distance between a pair of first laser type outer diameter gauges and the vertical separation distance between a pair of second laser type outer diameter gauges according to the outer diameter (nominal diameter) of the object to be measured to be measured. For this reason, even for an object to be measured with a wide range of outer diameters, such as a large diameter forged pipe with an outer diameter of 300 to 900 mm, it is possible to measure the outer diameter in the horizontal direction and the outer diameter in the vertical direction.

[0011] According to the calibration device of the present invention, when calibrating the outer diameter measuring device, the support is arranged such that its longitudinal direction coincides with the conveying direction of the object to be measured. For this reason, the first calibration bar attached to one end of the support and extending in the horizontal direction orthogonal to the longitudinal direction of the support extends in the horizontal direction orthogonal to the conveying direction of the object to be measured when calibrating the outer diameter measuring device. Therefore, it is possible to detect both ends of the first calibration bar with a pair of first laser type outer diameter gauges and calculate the length of the first calibration bar by the arithmetic means. Then, it is possible to calibrate the outer diameter measuring device so that the calculated length of the first calibration bar matches the true length of the first calibration bar. On the other hand, the second calibration bar attached to the other end of the support and extending in the vertical direction also extends in the vertical direction when calibrating the outer diameter measuring device. Therefore, it is possible to detect both ends of the second calibration bar with a pair of second laser type outer diameter gauges and calculate the length of the second calibration bar by the arithmetic means. Then, it is possible to calibrate the outer diameter measuring device so that the calculated length of the second calibration bar matches the true length of the second calibration bar. And since the support has a length corresponding to the separation distance in the transport direction of the object to be measured between the first laser type outer diameter gauge and the second laser type outer diameter gauge, the separation distance between the first calibration bar and the second calibration bar also becomes a distance corresponding to the separation distance between the first laser type outer diameter gauge and the second laser type outer diameter gauge. For this reason, without changing the arrangement position of the calibration device, using the calibration device arranged at the same position, both ends of the first calibration bar can be detected by a pair of first laser type outer diameter gauges, and at the same time, both ends of the second calibration bar can be detected by a pair of second laser type outer diameter gauges. That is, without changing the arrangement position of the calibration device, an outer diameter measuring device equipped with a pair of first laser type outer diameter gauges and a pair of second laser type outer diameter gauges can be calibrated. Also, conventionally, when calibrating an outer diameter measuring device, it is common to use a calibration sample having a substantially circular cross section similar to that of the object to be measured. However, since a calibration sample having an outer diameter of 300 mm or more has a large weight, it is not easy to carry. On the other hand, in the calibration device according to the present invention, since a narrow thin plate-like member can be used as the first calibration bar and the second calibration bar, even if its length is 300 mm or more, the weight is smaller than that of the above-mentioned calibration sample, and it is easy to carry. As described above, since the calibration device according to the present invention does not need to change the arrangement position and is also easy to carry, it is possible to efficiently calibrate the outer diameter measuring device.

[0012] Note that according to the calibration device of the present invention, since the first calibration bar and the second calibration bar are detachably attached to the ends of the support, for example, by repeatedly performing calibration by replacing them with first calibration bars and second calibration bars having different lengths, it is possible to improve the calibration accuracy. Further, according to the calibration device of the present invention, the first calibration bar is movable in a horizontal direction perpendicular to the longitudinal direction of the support with respect to the support. That is, when calibrating the outer diameter measuring device, the first calibration bar is movable in a horizontal direction perpendicular to the conveyance direction of the object to be measured. Therefore, by moving the first calibration bar, the positions of both ends of the first calibration bar detected by the pair of first laser type outer diameter gauges can be changed. If the object to be measured has a horizontal bend or meandering during conveyance, even if there is no variation in the horizontal outer diameter of the object to be measured, the horizontal end positions of the object to be measured will vary. Therefore, by changing the positions of both ends of the first calibration bar and repeating the calibration, it is possible to reduce the influence of the horizontal bend or meandering of the object to be measured. Similarly, according to the calibration device of the present invention, the second calibration bar is movable in the vertical direction with respect to the support. That is, when calibrating the outer diameter measuring device, the second calibration bar is movable in the vertical direction. Therefore, by moving the second calibration bar, the positions of both ends of the second calibration bar detected by the pair of second laser type outer diameter gauges can be changed. If the object to be measured has a vertical bend, even if there is no variation in the vertical outer diameter of the object to be measured, the vertical end positions of the object to be measured will vary. Therefore, by changing the positions of both ends of the second calibration bar and repeating the calibration, it is possible to reduce the influence of the vertical bend of the object to be measured.

[0013] Furthermore, in order to solve the above problems, the present invention provides Outer A method for measuring the outer diameter of a long object to be measured having a substantially circular cross-section with an outer diameter of 300 mm or more and conveyed in the axial direction, using an outer diameter measuring device, comprising The outer diameter measuring device is arranged on both horizontal sides perpendicular to the conveying direction of the object to be measured with the object to be measured sandwiched therebetween, and includes a pair of first laser type outer diameter gauges for detecting both end positions in the horizontal direction of the object to be measured. A pair of second laser type outer diameter gauges are arranged on both upper and lower sides with the object to be measured sandwiched therebetween at positions spaced apart from the pair of first laser type outer diameter gauges in the conveying direction of the object to be measured, for detecting both end positions in the vertical direction of the object to be measured. First driving means for adjusting the horizontal separation distance of the pair of first laser type outer diameter gauges, second driving means for adjusting the vertical separation distance of the pair of second laser type outer diameter gauges, a speed sensor for measuring the conveying speed of the object to be measured, and arithmetic means for calculating the outer diameter of the object to be measured. The second driving means includes an arm to which the lower second laser type outer diameter gauge of the pair of second laser type outer diameter gauges is attached, and the arm is stationary at a fixed position without moving in the vertical direction. The arithmetic means calculates the outer diameter in the horizontal direction of the object to be measured based on both end positions in the horizontal direction of the object to be measured detected by the pair of first laser type outer diameter gauges whose horizontal separation distance is adjusted by the first driving means, and calculates the outer diameter in the vertical direction of the object to be measured based on both end positions in the vertical direction of the object to be measured detected by the pair of second laser type outer diameter gauges whose vertical separation distance is adjusted by the second driving means. Based on the conveying speed of the object to be measured measured by the speed sensor, the outer diameter in the horizontal direction and the outer diameter in the vertical direction of the object to be measured are associated with the axial position of the object to be measured. The method is A calibration step of calibrating the outer diameter measuring device using the calibration device, and a measurement step of measuring the outer diameter of the object to be measured using the outer diameter measuring device after calibration in the calibration step, wherein in the calibration step, as the first calibration bar and the second calibration bar, when bars having lengths corresponding to the maximum outer diameter of the object to be measured are respectively attached to the support, the lengths of the first calibration bar and the second calibration bar measured by the outer diameter measuring device respectively match the true lengths of the first calibration bar and the second calibration bar, and as the first calibration bar and the second calibration bar, when bars having lengths corresponding to the minimum outer diameter of the object to be measured are respectively attached to the support, the lengths of the first calibration bar and the second calibration bar measured by the outer diameter measuring device respectively match the true lengths of the first calibration bar and the second calibration bar, and the outer diameter measuring device is calibrated. An outer diameter measuring method is provided.

[0014] According to the outer diameter measuring method of the present invention, in the calibration step, the outer diameter measuring device is calibrated using the first calibration bar and the second calibration bar having lengths corresponding to the maximum outer diameter of the object to be measured, and the outer diameter measuring device is calibrated using the first calibration bar and the second calibration bar having lengths corresponding to the minimum outer diameter of the object to be measured. In the measurement step, the outer diameter of the object to be measured is measured using the calibrated outer diameter measuring device. Therefore, accurate outer diameter measurement is possible in the range from the minimum outer diameter to the maximum outer diameter of the object to be measured.

Effects of the Invention

[0015] According to the present invention Calibration the device can associate the measured outer diameter in the horizontal direction and the outer diameter in the vertical direction of the object to be measured with the axial position of the object to be measured None It is possible to efficiently calibrate the outer diameter measuring device. Furthermore, according to the outer diameter measuring method of the present invention, it is possible to accurately measure the outer diameter of the object to be measured using the outer diameter measuring device according to the present invention and the calibration device according to the present invention.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0017] Hereinafter, with appropriate reference to the accompanying drawings, an outer diameter measuring device, a calibration device, and an outer diameter measuring method (calibration step) according to an embodiment of the present invention will be described by taking as an example the case where a long measurement object having a substantially circular cross section is a forged pipe with a large diameter (outer diameter of 300 to 900 mm) and is horizontally conveyed in the axial direction while the outer diameter is measured in the conveyance line of the inspection process. Note that each figure is shown for reference, and it should be noted that the dimensions, scales, and shapes of the components shown in each figure may be different from the actual ones.

[0018] <Outer diameter measuring device> First, the outer diameter measuring device according to the present embodiment will be described. FIG. 1 is a diagram schematically showing a schematic configuration of the outer diameter measuring device according to the present embodiment. FIG. 1(a) is a side view showing a schematic configuration of the entire outer diameter measuring device (a view seen from the horizontal direction (X direction) orthogonal to the conveyance direction (Z direction) of the measurement object), FIG. 1(b) is a front view showing an enlarged schematic configuration of the first laser type outer diameter gauge (a view seen from the conveyance direction of the measurement object), and FIG. 1(c) is a front view showing an enlarged schematic configuration of the second laser type outer diameter gauge (a view seen from the conveyance direction of the measurement object). In FIG. 1(a), for the sake of convenience, the illustration of the support parts 5 and 6 shown in FIG. 1(b) and the arms 7 and 8 shown in FIG. 1(c) is omitted. As shown in FIG. 1, the outer diameter measuring device 100 according to the present embodiment is a device for measuring the outer diameter of a measurement object (forged pipe) P that is conveyed in the axial direction (Z direction) by a conveying roller R installed on a conveying line. The device includes a pair of first laser-type outer diameter gauges 1 and 2, a pair of second laser-type outer diameter gauges 3 and 4, a first driving means (only the arms 5 and 6 constituting the first driving means are shown), a second driving means (only the arms 7 and 8 constituting the second driving means are shown), a speed sensor 9, and an arithmetic means 10. Further, the outer diameter measuring device 100 according to the present embodiment includes a photoelectric sensor 11.

[0019] The pair of first laser-type outer diameter gauges 1 and 2 are respectively arranged on both sides in the horizontal direction (X direction) perpendicular to the conveying direction of the measurement object P with the measurement object P sandwiched therebetween, and detect both end positions of the measurement object P in the horizontal direction. The pair of first laser-type outer diameter gauges 1 and 2 are electrically connected to the arithmetic means 10. The first laser-type outer diameter gauge 1 arranged on the left side of FIG. 1(b) includes a light projector 1a and a light receiver 1b that are arranged to face each other in the vertical direction (Y direction) with the left end of the measurement object P sandwiched therebetween. In the example shown in FIG. 1(b), the light projector 1a is arranged on the upper side and the light receiver 1b is arranged on the lower side, but the present invention is not limited to this, and a configuration in which the light projector 1a is arranged on the lower side and the light receiver 1b is arranged on the upper side may also be adopted. The first laser-type outer diameter gauge 2 arranged on the right side of FIG. 1(b) includes a light projector 2a and a light receiver 2b that are arranged to face each other in the vertical direction (Y direction) with the right end of the measurement object P sandwiched therebetween. In the example shown in FIG. 1(b), the light projector 2a is arranged on the upper side and the light receiver 2b is arranged on the lower side, but the present invention is not limited to this, and a configuration in which the light projector 2a is arranged on the lower side and the light receiver 2b is arranged on the upper side may also be adopted. Further, the present invention is not limited to a configuration in which both of the light projectors 1a and 2a are arranged on the same side in the vertical direction, and a configuration in which the light projector 1a is arranged on the upper side and the light projector 2a is arranged on the lower side, or a configuration in which the light projector 1a is arranged on the lower side and the light projector 2a is arranged on the upper side may also be adopted.

[0020] A pair of second laser type outer diameter gauges 3 and 4 are arranged at positions spaced apart in the conveyance direction (X direction) of the object to be measured P with respect to the pair of first laser type outer diameter gauges 1 and 2. In the example shown in Fig. 1(a), the pair of second laser type outer diameter gauges 3 and 4 are arranged at a separation distance L1 on the downstream side in the conveyance direction of the object to be measured P (the right side in Fig. 1(a)). However, the present invention is not limited to this, and a configuration in which the pair of first laser type outer diameter gauges 1 and 2 are arranged on the downstream side in the conveyance direction of the object to be measured with respect to the pair of second laser type outer diameter gauges 3 and 4 can also be adopted. The pair of second laser type outer diameter gauges 3 and 4 are respectively arranged on both sides in the vertical direction (Y direction) sandwiching the object to be measured P, and detect both end positions in the vertical direction of the object to be measured P. The pair of second laser type outer diameter gauges 3 and 4 are electrically connected to the arithmetic means 10. The second laser type outer diameter gauge 3 arranged on the upper side of Fig. 1(c) includes a light projector 3a and a light receiver 3b arranged to face each other in the left-right direction (X direction) sandwiching the upper end of the object to be measured P. In the example shown in Fig. 1(c), the light projector 3a is arranged on the left side and the light receiver 3b is arranged on the right side, but the present invention is not limited to this, and a configuration in which the light projector 3a is arranged on the right side and the light receiver 3b is arranged on the left side can also be adopted. The second laser type outer diameter gauge 4 arranged on the lower side of Fig. 1(c) includes a light projector 4a and a light receiver 4b arranged to face each other in the left-right direction (X direction) sandwiching the lower end of the object to be measured P. In the example shown in Fig. 1(c), the light projector 4a is arranged on the left side and the light receiver 4b is arranged on the right side, but the present invention is not limited to this, and a configuration in which the light projector 4a is arranged on the right side and the light receiver 4b is arranged on the left side can also be adopted. Also, the present invention is not limited to a configuration in which both of the light projectors 3a and 4a are arranged on the same side in the left-right direction, and a configuration in which the light projector 3a is arranged on the left side and the light projector 4a is arranged on the right side, or a configuration in which the light projector 3a is arranged on the right side and the light projector 4a is arranged on the left side can also be adopted.

[0021] The light projector 1a of the first laser type outer diameter gauge 1 is composed of a laser light source and a scanning optical system such as mirrors and lenses, and projects laser scanning light (in FIG. 1, dot-shaped hatching is applied to the laser scanning light) scanned in the X direction toward the light receiver 1b. The light receiver 1b is composed of a condensing optical system such as a lens and a light receiving element, and receives the laser scanning light that has reached the light receiver 1b without being blocked by the object P to be measured among the laser scanning light projected from the light projector 1a and converts it into an electrical signal. Then, the first laser type outer diameter gauge 1 outputs a value obtained by converting the scanning time of the laser scanning light received by the light receiver 1b (not blocked by the object P to be measured) into a length (the length L shown in FIG. 1(b)) XL ) to the arithmetic means 10 as the left end position of the object P to be measured. Note that the present invention is not limited to this, and conversely, a configuration may be adopted in which a value obtained by converting the scanning time of the laser scanning light not received by the light receiver 1b (blocked by the object P to be measured) into a length is output to the arithmetic means 10 as the left end position of the object P to be measured.

[0022] The light projectors 2a of the second laser type outer diameter gauge 2, the light projectors 3a of the second laser type outer diameter gauge 3, and the light projectors 4a of the second laser type outer diameter gauge 4 also have the same configuration as the light projector 1a of the first laser type outer diameter gauge 1, and the light receivers 2b of the second laser type outer diameter gauge 2, the light receivers 3b of the second laser type outer diameter gauge 3, and the light receivers 4b of the second laser type outer diameter gauge 4 also have the same configuration as the light receiver 1b of the first laser type outer diameter gauge 1. The scanning direction of the laser scanning light projected from the light projector 3a of the second laser type outer diameter gauge 3 and the light projector 4a of the second laser type outer diameter gauge 4 is the Y direction. Then, the second laser type outer diameter gauge 2 outputs a value obtained by converting the scanning time of the laser scanning light received by the light receiver 2b (not blocked by the object P to be measured) into a length (the length L shown in FIG. 1(b)) XR ) to the arithmetic means 10 as the right end position of the object P to be measured. However, the present invention is not limited to this, and conversely, a configuration may be adopted in which a value obtained by converting the scanning time of the laser scanning light not received by the light receiver 2b into a length is output to the arithmetic means 10 as the left end position of the object P to be measured. The second laser type outer diameter gauge 3 outputs a value obtained by converting the scanning time of the laser scanning light received by the light receiver 3b (not blocked by the object P to be measured) into a length (the length L shown in FIG. 1(c))YU ) is output to the arithmetic means 10 as the upper end position of the object P to be measured. However, it is not limited to this. Conversely, it is also possible to adopt a configuration in which a value obtained by converting the scanning time of the laser scanning light not received by the light receiver 3b into length is output to the arithmetic means 10 as the upper end position of the object P to be measured. The second laser type outer diameter gauge 4 outputs a value obtained by converting the scanning time of the laser scanning light received by the light receiver 4b (not blocked by the object P to be measured) into length (the length L shown in Fig. 1(c)) YL ) is output to the arithmetic means 10 as the lower end position of the object P to be measured. However, it is not limited to this. Conversely, it is also possible to adopt a configuration in which a value obtained by converting the scanning time of the laser scanning light not received by the light receiver 4b into length is output to the arithmetic means 10 as the lower end position of the object P to be measured.

[0023] The first driving means adjusts the separation distance in the horizontal direction (X direction) between the pair of first laser type outer diameter gauges 1 and 2. Specifically, the first driving means of the present embodiment includes an arm 5 to which the first laser type outer diameter gauge 1 (light projector 1a, light receiver 1b) is attached, and an arm 6 to which the first laser type outer diameter gauge 2 (light projector 2a, light receiver 2b) is attached. Further, the first driving means includes, for example, a servo motor (not shown) and a linear guide (not shown) extending in the horizontal direction (X direction). In the first driving means having the above configuration, by driving the servo motor, the arms 5 and 6 move horizontally along the linear guide. As a result, the first laser type outer diameter gauge 1 attached to the arm 5 also moves horizontally together with the arm 5. Similarly, the first laser type outer diameter gauge 2 attached to the arm 6 also moves horizontally together with the arm 6. The first driving means adjusts the separation distance in the horizontal direction between the pair of first laser type outer diameter gauges 1 and 2 by controlling the horizontal movement amount of each of the arms 5 and 6. Note that the horizontal movement amount of each of the arms 5 and 6 (the horizontal movement amount of the first laser type outer diameter gauges 1 and 2) controlled by the first driving means is output from the first driving means to the arithmetic means 10. However, the first driving means is not limited to the above configuration, and various configurations can be adopted as long as the horizontal separation distance between the pair of first laser type outer diameter gauges 1 and 2 can be adjusted.

[0024] The second driving means adjusts the vertical (Y-direction) separation distance between the pair of second laser type outer diameter gauges 3 and 4. Specifically, the second driving means of the present embodiment includes an arm 7 to which the second laser type outer diameter gauge 3 (light projector 3a, light receiver 3b) is attached, and an arm 8 to which the second laser type outer diameter gauge 4 (light projector 4a, light receiver 4b) is attached. Further, the second driving means includes, for example, a servo motor (not shown) and a linear guide (not shown) extending in the vertical direction (Y-direction). In the second driving means having the above configuration, by driving the servo motor, the arm 7 moves in the vertical direction along the linear guide. As a result, the second laser type outer diameter gauge 3 attached to the arm 7 also moves in the vertical direction together with the arm 7. On the other hand, in the present embodiment, the arm 8 does not move in the vertical direction and remains stationary at a fixed position. Therefore, the second laser type outer diameter gauge 4 attached to the arm 8 also does not move in the vertical direction. This is because even if the outer diameter of the object to be measured P changes, the object to be measured P is supported by the conveying roller R and there is no significant change in the lower end position of the object to be measured P, so there is no need to move it. The second driving means adjusts the vertical separation distance between the pair of second laser type outer diameter gauges 3 and 4 by controlling the vertical movement amount of the arm 7. Note that the vertical movement amount of the arm 7 (the vertical movement amount of the second laser type outer diameter gauge 3) controlled by the second driving means is output from the second driving means to the arithmetic means 10. However, the second driving means is not limited to the above configuration, and various configurations can be adopted as long as the vertical separation distance between the pair of second laser type outer diameter gauges 3 and 4 can be adjusted.

[0025] The speed sensor 9 measures the conveyance speed of the object P to be measured. Specifically, the speed sensor of the present embodiment includes a first photoelectric sensor 91 and a second photoelectric sensor 92 disposed on the downstream side in the conveyance direction of the object P to be measured with respect to the first photoelectric sensor 91 (the right side in FIG. 1(a)). Further, the arithmetic means 10 also constitutes a part of the speed sensor 9. The first photoelectric sensor 91 is a transmissive photoelectric sensor including a laser light source 9a and a light receiving element 9b that are disposed to face each other in the vertical direction (Y direction) across the conveyance line along which the object P to be measured is conveyed. However, the arrangement of the laser light source 9a and the light receiving element 9b is not limited thereto, and a configuration in which they are disposed to face each other in the horizontal direction (X direction) across the conveyance line may also be adopted. Similarly, the second photoelectric sensor 92 is a transmissive photoelectric sensor including a laser light source 9c and a light receiving element 9d that are disposed to face each other in the vertical direction (Y direction) across the conveyance line along which the object P to be measured is conveyed. However, the arrangement of the laser light source 9c and the light receiving element 9d is not limited thereto, and a configuration in which they are disposed to face each other in the horizontal direction (X direction) across the conveyance line may also be adopted. The light receiving element 9b of the first photoelectric sensor 91 and the light receiving element 9d of the second photoelectric sensor 92 are electrically connected to the arithmetic means 10.

[0026] When the tip (the downstream end in the conveyance direction) of the object P to be measured has not reached the position where the first photoelectric sensor 91 is disposed, the laser light projected from the laser light source 9a of the first photoelectric sensor 91 is received by the light receiving element 9b. When the tip of the object P to be measured reaches the position where the first photoelectric sensor 91 is disposed, the laser light projected from the laser light source 9a of the first photoelectric sensor 91 is blocked by the object P and is no longer received by the light receiving element 9b. Therefore, the electrical signal output from the light receiving element 9b switches from on to off at the timing when the tip of the object P to be measured reaches the position where the first photoelectric sensor 91 is disposed. Similarly, when the tip of the object P to be measured has not reached the position where the second photoelectric sensor 92 is disposed, the laser light projected from the laser light source 9c of the second photoelectric sensor 92 is received by the light receiving element 9d. When the tip of the object P to be measured reaches the position where the second photoelectric sensor 92 is disposed, the laser light projected from the laser light source 9c of the second photoelectric sensor 92 is blocked by the object P to be measured and is no longer received by the light receiving element 9d. For this reason, the electrical signal output from the light receiving element 9d switches from on to off at the timing when the tip of the object P to be measured reaches the position where the second photoelectric sensor 92 is disposed.

[0027] The arithmetic means 10 functioning as a part of the speed sensor 9 detects the time difference in the timing at which the electrical signals output from the light receiving elements 9b and 9d switch from on to off, and divides the separation distance L2 in the conveyance direction (Z direction) of the object P to be measured between the first photoelectric sensor 91 and the second photoelectric sensor 92 by the detected time difference, thereby calculating the conveyance speed of the object P to be measured. Note that the speed sensor 9 is not limited to the above configuration, and various configurations such as a combination of reflection-type photoelectric sensors and a laser Doppler velocimeter can be adopted as long as the conveyance speed of the object P to be measured can be measured.

[0028] The photoelectric sensor 11 is a transmissive photoelectric sensor including a laser light source 11a and a light receiving element 11b that are disposed to face each other in the vertical direction (Y direction) with the conveyance line along which the object P to be measured is conveyed interposed therebetween. However, the arrangement of the laser light source 11a and the light receiving element 11b is not limited to this, and a configuration in which they are disposed to face each other in the horizontal direction (X direction) with the conveyance line interposed therebetween can also be adopted. The light receiving element 11b of the photoelectric sensor 11 is electrically connected to the arithmetic means 10. After the tip of the object P to be measured reaches the position where the photoelectric sensor 11 is disposed, and before the rear end (the end on the upstream side in the conveyance direction) of the object P to be measured passes through, the laser light projected from the laser light source 11a of the photoelectric sensor 11 is blocked by the object P to be measured and is not received by the light receiving element 11b. However, when the rear end of the object P to be measured passes through the position where the photoelectric sensor 11 is disposed, the laser light projected from the laser light source 11a of the photoelectric sensor 11 comes to be received by the light receiving element 11b. For this reason, the electric signal output from the light receiving element 11b switches from off to on at the timing when the rear end of the object P to be measured passes through the position where the photoelectric sensor 11 is disposed. The photoelectric sensor 11 is used when the arithmetic means 10 stores the outer diameter of the object P to be measured (the outer diameter associated with the axial position of the object P to be measured) calculated by the arithmetic means 10, as will be described later. Specifically, the arithmetic means 10 stores the outer diameter of the object P to be measured calculated as will be described later at the timing when the electric signal output from the light receiving element 11b of the photoelectric sensor 11 switches from off to on.

[0029] The arithmetic means 10 calculates the outer diameter of the object P to be measured. Specifically, the arithmetic means 10 is based on the positions of both ends in the horizontal direction of the object P to be measured (the length L as the left end position XL and the length L as the right end position XR ) detected by a pair of first laser type outside diameter gauges 1 and 2 whose separation distance in the horizontal direction is adjusted by the first driving means (adjusted to a separation distance at which both end positions of the object P to be measured in the horizontal direction can be detected), and calculates the outer diameter OD X of the object P to be measured in the horizontal direction. More specifically, as shown in FIG. 1(b), when detecting the left end position of the object P to be measured, if the first laser type outside diameter gauge 1 is in a state of having moved by a length ΔLL XL in the horizontal direction from the horizontal reference position B1, this length ΔLL XL (the amount of movement in the horizontal direction) is input from the first driving means to the arithmetic means 10. Also, when detecting the right end position of the object P to be measured, if the first laser type outside diameter gauge 2 is in a state of having moved by a length ΔLL XR in the horizontal direction from the horizontal reference position B2, this length ΔLLXR (Horizontal movement amount) is input from the first driving means to the arithmetic means 10. And the arithmetic means 10 has a horizontal separation distance LL between a reference position B1, which is a fixed value, and a reference position B2 X0 stored in advance. Using these parameters, the arithmetic means 10 calculates the outer diameter OD in the horizontal direction of the object P to be measured X by the following formula (1). OD X =(LL X0 +ΔLL XL +ΔLL XR )-(L XL +L XR ) ···(1)

[0030] Also, the arithmetic means 10 calculates the outer diameter OD in the vertical direction of the object P to be measured based on the vertical end positions (length L as the upper end position YU , length L as the lower end position YL ) of the object P to be measured detected by a pair of second laser type outer diameter gauges 3 and 4 whose vertical separation distance is adjusted by the second driving means (adjusted to a separation distance at which both the upper and lower end positions of the object P to be measured can be detected). Y Specifically, as shown in Fig. 1(c), when detecting the upper end position of the object P to be measured, assuming that the second laser type outer diameter gauge 3 has moved by a length ΔLL in the vertical direction from the vertical reference position B3, this length ΔLL YU (vertical movement amount) is input from the second driving means to the arithmetic means 10. And the arithmetic means 10 has a vertical separation distance LL between a reference position B3, which is a fixed value, and the second laser type outer diameter gauge 4 (the lower end position of the laser scanning light projected from the light projector 4a of the second laser type outer diameter gauge 4) stored in advance. Using these parameters, the arithmetic means 10 calculates the outer diameter OD in the vertical direction of the object P to be measured YU by the following formula (2). Y0 is Y calculated. OD Y =(LL Y0 +ΔLL YU )-(L YU +L YL ) ···(2)

[0031] Then, based on the conveyance speed of the object P to be measured measured (calculated) as described above, the arithmetic means 10 determines the outer diameter OD in the horizontal direction of the object P to be measured X and the outer diameter OD in the vertical direction Y and associates them with the axial position of the object P to be measured. Specifically, in the arithmetic means 10 of the present embodiment, after the tip of the object P to be measured reaches the measurement positions of the pair of first laser type outer diameter gauges 1 and 2, and both end positions in the horizontal direction at the tip of the object P to be measured start to be detected by the pair of first laser type outer diameter gauges 1 and 2 (after the arithmetic means 10 starts calculating the outer diameter OD in the horizontal direction of the object P to be measured X ), the arithmetic means 10 multiplies the elapsed time by the conveyance speed of the object P to be measured measured by the speed sensor 9 to calculate the axial position (distance from the tip) of the object P to be measured at the elapsed time. Then, the arithmetic means 10 associates the calculated axial position of the object P to be measured with the outer diameter OD in the horizontal direction of the object P to be measured calculated at the elapsed time X . Similarly, in the arithmetic means 10 of the present embodiment, after the tip of the object P to be measured reaches the measurement positions of the pair of second laser type outer diameter gauges 3 and 4, and both end positions in the vertical direction at the tip of the object P to be measured start to be detected by the pair of second laser type outer diameter gauges 3 and 4 (after the arithmetic means 10 starts calculating the outer diameter OD in the vertical direction of the object P to be measured Y ), the arithmetic means 10 multiplies the elapsed time by the conveyance speed of the object P to be measured measured by the speed sensor 9 to calculate the axial position of the object P to be measured at the elapsed time. Then, the arithmetic means 10 associates the calculated axial position of the object P to be measured with the outer diameter OD in the vertical direction of the object P to be measured calculated at the elapsed time Y . The arithmetic means 10 stores the outer diameter OD in the horizontal direction of the object P to be measured and the outer diameter OD in the vertical direction of the object P to be measured associated with the axial position of the object P to be measured as described above X and the outer diameter OD in the vertical direction Y .

[0032] According to the outer diameter measuring device 100 according to the present embodiment described above, the outer diameters measured in different radial directions of the object P to be measured, specifically, the outer diameter OD in the horizontal direction of the measured object P to be measured X and the outer diameter OD in the vertical directionY It is possible to associate with the axial position of the object P to be measured. In the conveying line of the inspection process of the forged pipe, the outer diameter OD in the horizontal direction of the object P to be measured X and the outer diameter OD in the vertical direction Y Among them, in most cases, one of them becomes the maximum outer diameter and the other becomes the minimum outer diameter. Therefore, even if the outer diameter across the entire circumference of the object P to be measured is not measured, the difference between the outer diameter OD in the horizontal direction and the outer diameter OD in the vertical direction at the same axial position of the object P to be measured is divided by the average value of the two, and the ellipticity can be accurately calculated. X and the outer diameter OD in the vertical direction Y By dividing the difference between the two by the average value of the two, the ellipticity can be accurately calculated. Further, according to the outer diameter measuring device 100 according to the present embodiment, since it includes a first driving means for adjusting the horizontal separation distance between the pair of first laser type outer diameter gauges 1 and 2 and a second driving means for adjusting the vertical separation distance between the pair of second laser type outer diameter gauges 3 and 4, the horizontal both end positions of the object P to be measured can be detected by the pair of first laser type outer diameter gauges 1 and 2, and the vertical both end positions of the object P to be measured can be detected by the pair of second laser type outer diameter gauges 3 and 4. Therefore, according to the outer diameter (nominal diameter) of the object P to be measured, it is possible to adjust the horizontal separation distance between the pair of first laser type outer diameter gauges 1 and 2 and the vertical separation distance between the pair of second laser type outer diameter gauges 3 and 4. For this reason, even for a forged pipe with an outer diameter ranging from 300 to 900 mm like the object P to be measured in the present embodiment, the outer diameter OD in the horizontal direction X and the outer diameter OD in the vertical direction Y can be measured.

[0033] <Calibration device> Next, the calibration device according to the present embodiment used for calibrating the outer diameter measuring device 100 will be described. FIG. 2 is a diagram schematically showing a schematic configuration of the calibration device according to the present embodiment. FIG. 2(a) is a plan view of the calibration device (viewed from the vertical direction (Y direction)) showing the arrangement state when calibrating the outer diameter measuring device 100, and FIG. 2(b) is a side view of the calibration device (viewed from the horizontal direction (X direction) orthogonal to the transport direction (Z direction) of the object to be measured P) showing the arrangement state when calibrating the outer diameter measuring device 100, and FIG. 2(c) is a front view of the calibration device (viewed from the transport direction of the object to be measured P) showing the arrangement state when calibrating the outer diameter measuring device 100. As shown in FIG. 2, the calibration device 200 according to the present embodiment includes a support 21, a first calibration bar 22, and a second calibration bar 23. Further, the calibration device 200 according to the present embodiment includes a base 24 and a support column 25.

[0034] The support 21 extends in the horizontal direction and is arranged such that its longitudinal direction coincides with the transport direction (Z direction) of the object to be measured P when calibrating the outer diameter measuring device 100. Further, the support 21 is arranged such that the center position of the support 21 in the X direction coincides with the center position of the transport line of the object to be measured P in the X direction. The support 21 has a length L3 corresponding to the separation distance L1 (see FIG. 1(a)) between the first laser type outer diameter gauges 1 and 2 and the second laser type outer diameter gauges 3 and 4. That is, the length L3 of the support 21 is a value equivalent to the separation distance L1 between the first laser type outer diameter gauges 1 and 2 and the second laser type outer diameter gauges 3 and 4. The support 21 of the present embodiment has a cylindrical shape, and cutouts with a rectangular cross-section are formed at both ends thereof. The support 21 of the present embodiment is supported by a pair of support columns 25 erected on the base 24.

[0035] The first calibration bar 22 is detachably attached to one end of the support 21 (in the arrangement state when calibrating the outer diameter measuring device 100, it is the end on the upstream side in the conveyance direction of the object P to be measured), and extends in the horizontal direction (X direction) orthogonal to the longitudinal direction (Z direction) of the support 21. Specifically, the first calibration bar 22 of the present embodiment is a thin plate member having a rectangular cross section and a narrow width (small dimension in the Z direction), and is attached by being fitted into a rectangular notch formed at one end of the support 21 with a clearance. Since the first calibration bar 22 is attached to one end of the support 21 with a clearance, it is movable in the horizontal direction (X direction) orthogonal to the longitudinal direction of the support 21 with respect to the support 21.

[0036] The second calibration bar 23 is detachably attached to the other end of the support 21 (in the arrangement state when calibrating the outer diameter measuring device 100, it is the end on the downstream side in the conveyance direction of the object P to be measured), and extends in the vertical direction (Y direction). Specifically, the second calibration bar 23 of the present embodiment is a thin plate member having a rectangular cross section and a narrow width (small dimension in the X direction), and is attached by being fitted into a rectangular notch formed at the other end of the support 21 with a clearance. Since the second calibration bar 23 is attached to the other end of the support 21 with a clearance, it is movable in the vertical direction (Y direction) with respect to the support 21. Note that the second calibration bar 23 is fixed to the support 21 at a predetermined position in the vertical direction by a detachable fixture (not shown) so as not to fall due to its own weight. When moving the second calibration bar 23 in the vertical direction, the fixture is removed.

[0037] According to the calibration device 200 according to this embodiment, both ends of the first calibration bar 22 can be detected by a pair of first laser type outer diameter gauges 1 and 2, and the length of the first calibration bar 22 can be calculated by the calculation means 10. Then, the outer diameter measuring device 100 can be calibrated so that the calculated length of the first calibration bar 22 matches the true length of the first calibration bar 22. Further, both ends of the second calibration bar 23 can be detected by a pair of second laser type outer diameter gauges 3 and 4, and the length of the second calibration bar 23 can be calculated by the calculation means 10. Then, the outer diameter measuring device 100 can be calibrated so that the calculated length of the second calibration bar 23 matches the true length of the second calibration bar 23. In addition, as the calibration of the outer diameter measuring device 100, for example, the scanning time of the laser scanning light received by the light receivers 1b and 2b of the first laser type outer diameter gauges 1 and 2 is converted into the length L XL , L XR When converting, the adjustment of the correspondence relationship between the scanning time and the length, and the horizontal movement amount (length ΔLL XL , ΔLL XR ) of the pair of first laser type outer diameter gauges 1 and 2 input from the first driving means to the calculation means 10 when adjusting the horizontal separation distance of the pair of first laser type outer diameter gauges 1 and 2 by the first driving means. The adjustment of the correction amount for correcting the error of, etc., the horizontal outer diameter OD of the object to be measured P calculated by the above formula (1) X The adjustment of the parameters that affect is performed. The same applies to the second laser type outer diameter gauges 3 and 4.

[0038] According to the calibration device 200 according to the present embodiment, since the support 21 has a length L3 corresponding to the separation distance L1 in the transport direction of the object P to be measured between the first laser type outer diameter gauges 1 and 2 and the second laser type outer diameter gauges 3 and 4, the separation distance between the first calibration bar 22 and the second calibration bar 23 is also a distance corresponding to the separation distance L1 between the first laser type outer diameter gauges 1 and 2 and the second laser type outer diameter gauges 3 and 4. Therefore, without changing the arrangement position of the calibration device 200, using the calibration device 200 arranged at the same position, both ends of the first calibration bar 22 can be detected by the pair of first laser type outer diameter gauges 1 and 2, and at the same time, both ends of the second calibration bar 23 can be detected by the pair of second laser type outer diameter gauges 3 and 4. That is, without changing the arrangement position of the calibration device 200, the outer diameter measuring device 100 including the pair of first laser type outer diameter gauges 1 and 2 and the pair of second laser type outer diameter gauges 3 and 4 can be calibrated. Further, since the calibration device 200 according to the present embodiment uses narrow plate-like members as the first calibration bar 22 and the second calibration bar 23, it has a small weight and is easy to carry. As described above, since the calibration device 200 according to the present embodiment does not need to change its arrangement position and is easy to carry, it is possible to efficiently calibrate the outer diameter measuring device 100.

[0039] Further, according to the calibration device 200 according to the present embodiment, by moving the first calibration bar 22, the positions of both ends of the first calibration bar 22 detected by the pair of first laser type outer diameter gauges 1 and 2 can be changed. In other words, it is possible to simulate the horizontal bending or meandering during conveyance that may occur in the object P to be measured. Therefore, by changing the positions of both ends of the first calibration bar 22 and repeating the calibration, it is possible to reduce the influence of the horizontal bending and meandering of the object P to be measured. Similarly, according to the calibration device 200 according to the present embodiment, by moving the second calibration bar 23, the positions of both ends of the second calibration bar 23 detected by the pair of second laser type outer diameter gauges 3 and 4 can be changed. In other words, it is possible to simulate the vertical bending that may occur in the object P to be measured. Therefore, by changing the positions of both ends of the second calibration bar 23 and repeating the calibration, it is possible to reduce the influence of the vertical bending of the object P to be measured.

[0040] <Outer diameter measurement method (calibration step)> The outer diameter measurement method according to this embodiment is a method for measuring the outer diameter of the object to be measured P using the outer diameter measurement device 100 according to this embodiment, and includes a calibration step of calibrating the outer diameter measurement device 100 using the calibration device 200 according to this embodiment, and a measurement step of measuring the outer diameter of the object to be measured P using the outer diameter measurement device 100 after calibration in the calibration step. Hereinafter, the calibration step will be described.

[0041] FIG. 3 is a front view schematically showing a state in which the calibration step is being executed (a view seen from the conveyance direction (Z direction) of the object to be measured P). As shown in FIG. 3(a), in the calibration step, as the first calibration bar 22 and the second calibration bar 23, bars having lengths corresponding to the maximum outer diameter of the object to be measured P (900 mm in this embodiment) (in FIG. 3(a), the first calibration bar 22a having a length corresponding to the maximum outer diameter is shown as the "first calibration bar 22a", and the second calibration bar 23a having a length corresponding to the maximum outer diameter is shown as the "second calibration bar 23a") are respectively attached to the support 21. Then, the outer diameter measurement device 100 is calibrated so that the lengths of the first calibration bar 22a measured using the first laser-type outer diameter gauges 1 and 2 of the outer diameter measurement device 100 and the second calibration bar 23a measured using the second laser-type outer diameter gauges 3 and 4 match the true lengths of the first calibration bar 22a and the second calibration bar 23a (900 mm in this embodiment), respectively. Next, as shown in FIG. 3(b), after removing the first calibration bar 22a and the second calibration bar 23a from the support 21, as the first calibration bar 22 and the second calibration bar 23, bars having lengths corresponding to the minimum outer diameter of the object P to be measured (300 mm in this embodiment) (in FIG. 3(b), the first calibration bar 22 having a length corresponding to the minimum outer diameter is shown as the "first calibration bar 22b", and the second calibration bar 23 having a length corresponding to the minimum outer diameter is shown as the "second calibration bar 23b") are respectively attached to the support 21. Then, the outer diameter measuring device 100 is calibrated so that the lengths of the first calibration bar 22b measured using the first laser type outer diameter gauges 1 and 2 of the outer diameter measuring device 100 and the second calibration bar 23b measured using the second laser type outer diameter gauges 3 and 4 respectively match the true lengths of the first calibration bar 22b and the second calibration bar 23b (300 mm in this embodiment).

[0042] In the above description, the procedure of calibrating the outer diameter measuring device 100 using the first calibration bar 22a and the second calibration bar 23a and then calibrating the outer diameter measuring device 100 using the first calibration bar 22b and the second calibration bar 23b has been described, but it is not limited to this. It is also possible to adopt a procedure of calibrating the outer diameter measuring device 100 using the first calibration bar 22b and the second calibration bar 23b and then calibrating the outer diameter measuring device 100 using the first calibration bar 22a and the second calibration bar 23a.

[0043] According to the outer diameter measuring method according to this embodiment, in the calibration step, the outer diameter measuring device 100 is calibrated using the first calibration bar 22a and the second calibration bar 23a having lengths corresponding to the maximum outer diameter of the object P to be measured, and the outer diameter measuring device 100 is calibrated using the first calibration bar 22b and the second calibration bar 23b having lengths corresponding to the minimum outer diameter of the object P to be measured. In the measurement step, the outer diameter of the object P to be measured is measured using the calibrated outer diameter measuring device 100. Therefore, accurate outer diameter measurement is possible in the range from the minimum outer diameter to the maximum outer diameter of the object P to be measured.

[0044] FIG. 4 is a diagram showing an example of measurement results using the outer diameter measuring device 100 according to the present embodiment after calibration. FIG. 4(a) shows the outer diameter OD in the horizontal direction of the object P to be measured (nominal diameter 318.5 mm). X This is an example of the result of measuring the outer diameter OD in the vertical direction of the same object P to be measured as in FIG. 4(a), and FIG. 4(c) is an example of the result of measuring the lengths of the first calibration bar 22b and the second calibration bar 23b (true length 300 mm). Y This is an example of the result of measuring the outer diameter OD in the vertical direction of the same object P to be measured as in FIG. 4(a), and FIG. 4(c) is an example of the result of measuring the lengths of the first calibration bar 22b and the second calibration bar 23b (true length 300 mm).

[0045] In FIG. 4(a), the measured values of the outer diameter OD at each axial position from the tip of the object P to be measured are plotted as "○", and the errors (the differences from the outer diameters manually measured using measuring instruments) are plotted as "□". Also, in FIG. 4(b), the measured values of the outer diameter OD at each axial position from the tip of the object P to be measured are plotted as "○", and the errors (the differences from the outer diameters manually measured using measuring instruments) are plotted as "■". X In FIG. 4(a), the measured values of the outer diameter OD at each axial position from the tip of the object P to be measured are plotted as "○", and the errors (the differences from the outer diameters manually measured using measuring instruments) are plotted as "□". Also, in FIG. 4(b), the measured values of the outer diameter OD at each axial position from the tip of the object P to be measured are plotted as "○", and the errors (the differences from the outer diameters manually measured using measuring instruments) are plotted as "■". Y In FIG. 4(a), the measured values of the outer diameter OD at each axial position from the tip of the object P to be measured are plotted as "○", and the errors (the differences from the outer diameters manually measured using measuring instruments) are plotted as "□". Also, in FIG. 4(b), the measured values of the outer diameter OD at each axial position from the tip of the object P to be measured are plotted as "○", and the errors (the differences from the outer diameters manually measured using measuring instruments) are plotted as "■". As can be seen from FIGS. 4(a) and 4(b), when the outer diameter measuring device 100 according to the present embodiment is used, the error is within ±0.15 mm, and it can be seen that the outer diameter of the object P to be measured can be accurately measured.

[0046] The horizontal axis in FIG. 4(c) indicates the amount of deviation from a predetermined reference position of the first calibration bar 22b and the second calibration bar 23b. For the first calibration bar 22b, it means the amount of deviation in the horizontal direction (X direction), and for the second calibration bar 23b, it means the amount of deviation in the vertical direction (Y direction). In FIG. 4(c), the error (the difference from the true length of 300 mm) of the measured value of the length of the first calibration bar 22b when shifted by each amount of deviation is plotted as "□", and the error (the difference from the true length of 300 mm) of the measured value of the length of the second calibration bar 23b is plotted as "■". As can be seen from FIG. 4(c), when the outer diameter measuring device 100 according to the present embodiment is used, the error is within ±0.1 mm, and it can be seen that even if the object P to be measured has a bend of about ±30 mm in the horizontal direction or the vertical direction from the reference position or a meandering during conveyance, the outer diameter of the object P to be measured can be accurately measured.

Description of Reference Numerals

[0047] 1, 2... First laser type outer diameter gauge 3, 4... Second laser type outer diameter gauge 5, 6... Arm (first driving means) 7, 8... Arm (second driving means) 9... Speed sensor 10... Calculation means 100... Outer diameter measuring device 200... Calibration device P... Object to be measured

Claims

A calibration device used for calibrating an outer diameter measuring device, wherein the outer diameter measuring device is a device for measuring the outer diameter of a long measurement object having an outer diameter of 300 mm or more and having a substantially circular cross-section and being horizontally conveyed in the axial direction, a pair of first laser-type outer diameter gauges respectively arranged on both horizontal sides orthogonal to the conveyance direction of the measurement object with the measurement object sandwiched therebetween, for detecting both end positions of the measurement object in the horizontal direction; a pair of second laser-type outer diameter gauges respectively arranged on both upper and lower sides sandwiching the measurement object at positions spaced apart from the pair of first laser-type outer diameter gauges in the conveyance direction of the measurement object, for detecting both end positions of the measurement object in the vertical direction; first driving means for adjusting the horizontal separation distance between the pair of first laser-type outer diameter gauges; second driving means for adjusting the vertical separation distance between the pair of second laser-type outer diameter gauges; a speed sensor for measuring the conveyance speed of the measurement object; and arithmetic means for calculating the outer diameter of the measurement object, and is provided with: the second driving means includes an arm to which the lower second laser-type outer diameter gauge of the pair of second laser-type outer diameter gauges is attached, and the arm is stationary at a fixed position without moving in the vertical direction; the arithmetic means calculates the outer diameter of the measurement object in the horizontal direction based on both end positions of the measurement object in the horizontal direction detected by the pair of first laser-type outer diameter gauges whose horizontal separation distance has been adjusted by the first driving means, and calculates the outer diameter of the measurement object in the vertical direction based on both end positions of the measurement object in the vertical direction detected by the pair of second laser-type outer diameter gauges whose vertical separation distance has been adjusted by the second driving means, and associates the outer diameter of the measurement object in the horizontal direction and the outer diameter in the vertical direction with the axial position of the measurement object based on the conveyance speed of the measurement object measured by the speed sensor; the calibration device having a length corresponding to the separation distance in the transport direction of the object to be measured between the first laser type outer diameter gauge and the second laser type outer diameter gauge, extending horizontally, and when calibrating the outer diameter measuring device, being arranged such that the longitudinal direction coincides with the transport direction of the object to be measured; a support body, detachably attached to one end of the support body, extending horizontally in a direction orthogonal to the longitudinal direction of the support body, and a first calibration bar movable in a horizontal direction orthogonal to the longitudinal direction of the support body with respect to the support body; detachably attached to the other end of the support body, extending in the vertical direction, and a second calibration bar movable in the vertical direction with respect to the support body, comprising: A calibration device. A method for measuring the outer diameter of a long object to be measured having an outer diameter of 300 mm or more and having a substantially circular cross-section transported in the axial direction using an outer diameter measuring device, The outer diameter measuring device is A pair of first laser type outer diameter gauges respectively arranged on both horizontal sides orthogonal to the transport direction of the object to be measured sandwiching the object to be measured, for detecting both end positions in the horizontal direction of the object to be measured; At positions separated from the pair of first laser type outer diameter gauges in the transport direction of the object to be measured, a pair of second laser type outer diameter gauges respectively arranged on both upper and lower sides sandwiching the object to be measured, for detecting both end positions in the vertical direction of the object to be measured; First driving means for adjusting the horizontal separation distance of the pair of first laser type outer diameter gauges; Second driving means for adjusting the vertical separation distance of the pair of second laser type outer diameter gauges; A speed sensor for measuring the transport speed of the object to be measured; Calculating means for calculating the outer diameter of the object to be measured, comprising: The second driving means includes an arm to which the lower second laser type outer diameter gauge of the pair of second laser type outer diameter gauges is attached, and the arm is stationary at a fixed position without moving in the vertical direction. The arithmetic means calculates the outer diameter of the object to be measured in the horizontal direction based on the positions of both ends of the object to be measured in the horizontal direction detected by the pair of first laser type outer diameter gauges whose separation distance in the horizontal direction is adjusted by the first driving means, and calculates the outer diameter of the object to be measured in the vertical direction based on the positions of both ends of the object to be measured in the vertical direction detected by the pair of second laser type outer diameter gauges whose separation distance in the vertical direction is adjusted by the second driving means. Based on the conveyance speed of the object to be measured measured by the speed sensor, the outer diameter of the object to be measured in the horizontal direction and the outer diameter in the vertical direction are associated with the axial position of the object to be measured. The method includes: a calibration step of calibrating the outer diameter measuring device using the calibration device according to claim 1; a measuring step of measuring the outer diameter of the object to be measured using the outer diameter measuring device after calibration in the calibration step. In the calibration step, when bars having lengths corresponding to the maximum outer diameter of the object to be measured are respectively attached to the support as the first calibration bar and the second calibration bar, the lengths of the first calibration bar and the second calibration bar measured by the outer diameter measuring device match the true lengths of the first calibration bar and the second calibration bar respectively, and when bars having lengths corresponding to the minimum outer diameter of the object to be measured are respectively attached to the support as the first calibration bar and the second calibration bar, the outer diameter measuring device is calibrated so that the lengths of the first calibration bar and the second calibration bar measured by the outer diameter measuring device match the true lengths of the first calibration bar and the second calibration bar respectively. Outer diameter measuring method.

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