JP2016200530A - Roundness measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a total inspection without requiring an alignment operation and to allow even a work such as a pipe-like work to be measured in a roundness measurement device.SOLUTION: A roundness measurement device 1 includes a reference axis A which extends in the direction of an axial line Wb of an inner peripheral surface Wa formed in a cylindrical surface shape of a work W to be measured. The roundness measurement device 1 includes: light irradiation means 2 for radially radiating light for illuminating a region Wa1 at a predetermined position in a direction of the reference axis A in the inner peripheral surface Wa; imaging means 3 for imaging the inner peripheral surface Wa so as to form image data; and computation means 4 for calculating a roundness of the inner peripheral surface Wa on the basis of the image data. In the roundness measurement device 1, the light irradiation means 2 illuminating the inner peripheral surface Wa moves in the inner side of the inner peripheral surface Wa along the direction of the reference axis A, and the imaging means 3 moves. The light irradiation means 2 and the imaging means 3 move while maintaining a constant distance between them due to connection effected by a coupling member 8.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for improving a roundness measuring apparatus that measures the roundness of an inner peripheral surface of a workpiece to be measured.

  For example, as a roundness measuring device for measuring the roundness of the inner peripheral surface of the workpiece to be measured, the workpiece is rotated, the distance between the rotation center axis of the workpiece to be measured and the inner peripheral surface is measured, A device that calculates the roundness from the result is known (for example, see Patent Document 1).

  In this type of roundness measuring device, in order to improve the measurement accuracy of roundness, it is possible to accurately align the rotation center axis of the workpiece to be measured and the axis of the inner peripheral surface of the workpiece to be measured. Although essential, this alignment process is very time consuming and labor intensive. Therefore, it has been difficult to perform a total inspection of the roundness of a large number of workpieces.

  On the other hand, for example, Patent Document 2 proposes a roundness measuring apparatus that measures the roundness of the inner peripheral surface without rotating the workpiece to be measured. The roundness measuring apparatus includes a light irradiation unit for illuminating an inner peripheral surface of a workpiece to be measured, an imaging unit that images the inner peripheral surface to form image data, and the inner periphery based on the image data. Computing means for computing the roundness of the surface.

JP 2009-257887 A JP 2008-209380 A

  However, the inner surface of the workpiece to be measured of the roundness measuring device of Patent Document 2 must have a bottomed cylindrical surface shape. This is because the roundness measuring device makes the irradiated light as a straight beam having a diameter smaller than the inner diameter of the workpiece to be measured, incident on the inner surface of the workpiece to be measured, and reflected by the bottom surface. It is because it images. Therefore, this roundness measuring apparatus cannot measure a pipe-shaped workpiece having a cylindrical inner surface without a bottom surface. Moreover, since this roundness measuring apparatus captures an image of light reflected from the bottom surface, it can only measure the roundness around the opening on the inner peripheral surface of the workpiece to be measured. For this reason, this roundness measuring apparatus cannot measure the roundness, cylindricity, and concentricity of the inner circumference of the work to be measured. That is, the roundness measuring device of Patent Document 2 still leaves room for improvement as a roundness measuring device.

  In view of the above circumstances, an object of the present invention is to make it possible to perform a complete inspection in a roundness measuring device without requiring an alignment operation, and to make it possible to measure even a workpiece such as a pipe.

  The roundness measuring apparatus according to the present invention, which was created to solve the above-mentioned problems, includes a light irradiation means for illuminating the cylindrical inner peripheral surface of the workpiece to be measured, and an image obtained by imaging the inner peripheral surface. A reference axis extending in the direction of the axis of the inner peripheral surface in a roundness measuring apparatus comprising imaging means for forming data and a calculating means for calculating the roundness of the inner peripheral surface based on the image data A first moving means for moving the light irradiation means illuminating the inner peripheral surface along the direction of the reference axis on the inner side of the inner peripheral surface, and the imaging along the direction of the reference axis A second moving means for moving the means, and the light irradiating means and the imaging means are configured to move while maintaining a certain distance. Here, the “reference axis extending in the direction of the axis of the inner peripheral surface” includes a reference axis inclined with respect to the direction of the axis of the inner peripheral surface (hereinafter the same). The definition and display of roundness conform to JIS B 0621: 1984.

  According to this configuration, since the roundness of the inner peripheral surface is calculated based on the image data of the inner peripheral surface, there is no need to rotate the workpiece to be measured. Therefore, an axis alignment operation can be made unnecessary. Accordingly, since the time required for measuring the roundness can be shortened, it is possible to inspect all the workpieces to be measured.

  Also, the light irradiation means illuminating the inner peripheral surface moves inside the inner peripheral surface, and the light irradiation means and the imaging means move while maintaining a certain distance. The degree can be measured. Also, the cylindricity and coaxiality can be measured.

  Further, if the inner peripheral surface where the roundness is to be measured falls within the field of view of the imaging means, the roundness is measured no matter where the axis of the workpiece to be measured is located in the direction perpendicular to the reference axis. be able to. Therefore, it is not necessary to position the workpiece to be measured in a direction perpendicular to the reference axis with high accuracy.

  In the above configuration, when viewed in a direction along the reference axis, the light irradiation unit may simultaneously irradiate light radially.

  With this configuration, the image data of the inner peripheral surface can be obtained in a shorter time than when the light irradiation means scans the light and irradiates the inner peripheral surface.

  In the above configuration, a connecting member that connects the light irradiation unit and the imaging unit may be provided, and the second moving unit may also serve as the first moving unit.

  If it is this structure, since a light irradiation means and an imaging means can maintain a fixed distance and a 2nd moving means can serve as a 1st moving means with a connection member, manufacturing cost can be reduced. In addition, it is easy to introduce the light irradiation unit from the opening at one end of the inner peripheral surface to the inside of the inner peripheral surface while maintaining a certain distance from the imaging unit. Therefore, even in the case of a workpiece to be measured in which one end of the inner peripheral surface is closed, the roundness can be easily measured.

  In the above configuration, the calculation means may correct the roundness based on an inclination angle of the axis with respect to the reference axis.

  With this configuration, the roundness can be accurately measured even when the axis of the inner peripheral surface is inclined with respect to the reference axis.

  In the above configuration, the calculation means may calculate the tilt angle based on a position of the axis on a different plane among the planes perpendicular to the reference axis.

  With this configuration, the tilt angle can be easily calculated.

  In the above configuration, the calculation unit may calculate the position of the axis with respect to the position on the vertical plane with respect to the reference axis with reference to the position of the axis of the cylindrical inner peripheral surface of the master work. .

  With this configuration, the roundness can be measured more accurately.

  As described above, according to the present invention, in the roundness measuring device, it is possible to perform a complete inspection without requiring an alignment operation, and it is also possible to measure a workpiece such as a pipe without contact. In addition to roundness, inner diameter, cylindricity, and coaxiality can be measured simultaneously.

It is a general | schematic fragmentary sectional side view which shows the roundness measuring apparatus which concerns on embodiment of this invention. (A) is a schematic plan view of the periphery of the light irradiation means, and (B) is a schematic side view of the periphery of the light irradiation means. It is the schematic which shows the image data formed by an imaging means, When (A) is not inclined with respect to a reference axis with respect to the axis of a to-be-measured workpiece, (B) is an axis of a to-be-measured workpiece with a reference axis It is a case where it inclines with respect to. It is the schematic which shows the state where the shadow of the connection member appeared in image data, (A) is a case where there are three connection members, (B) is a case where there are four connection members. It is the schematic which shows the example of a two-dimensional display of the deviation by a display means. It is a schematic longitudinal cross-sectional view which shows the state in which the axis line of the to-be-measured workpiece is inclined with respect to the reference axis. It is a table | surface which shows the specific example of the value of a coordinate. It is a graph of the data of FIG. It is the schematic which shows the example of a three-dimensional display of the deviation or radius by a display means.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic partial cross-sectional side view showing a roundness measuring apparatus 1 according to an embodiment of the present invention. A workpiece W measured by the roundness measuring device 1 has a cylindrical inner peripheral surface Wa. The workpiece W to be measured is arranged such that the axis Wb of the inner peripheral surface Wa is in the vertical direction. In the present embodiment, the workpiece W to be measured is a circular tubular body. However, as long as it has a cylindrical inner peripheral surface, for example, the outer surface may have a polygonal cross section.

  The roundness measuring apparatus 1 is based on the light irradiation means 2 for illuminating the inner peripheral surface Wa of the workpiece W to be measured, the imaging means 3 for imaging the inner peripheral surface Wa to form image data, and the image data. A calculating means 4 for calculating the roundness of the inner peripheral surface Wa, a moving means 5 as a second moving means for moving the imaging means 3, and a supporting means 6 for supporting the workpiece W to be measured. The display means 7 for displaying the roundness calculated by the calculation means 4 is a main component.

  Moreover, the roundness measuring device 1 includes a reference axis A that extends in the direction of the axis Wb of the inner peripheral surface Wa. The reference axis A is a virtual axis that serves as a reference when measuring roundness, and corresponds to a Z-axis of coordinates described later. The (extending) direction of the reference axis A is the vertical direction.

  The moving unit 5 is configured such that the moving unit 5b moves along the guide unit 5a by being controlled by a control unit (not shown). For example, the moving unit 5 is configured by a single-axis robot or the like. The light irradiation means 2 and the imaging means 3 are connected by a connecting member 8, and the imaging means 3 is fixed to the moving part 5b. By the connection of the connecting member 8, the moving means 5 also serves as a first moving means for moving the light irradiation means 2.

  At the time of measuring roundness or the like, the light irradiating means illuminates the inner peripheral surface Wa along the direction of the reference axis A on the inner side of the inner peripheral surface Wa by moving the moving portion 5b along the guide portion 5a. 2 moves. Then, the imaging unit 3 moves along the direction of the reference axis A while maintaining a certain distance from the light irradiation unit 2.

  The supporting means 6 such as a mounting table is formed with a recess 6a on which the workpiece W to be measured is mounted. The recess 6a has a circular and flat bottom surface (support surface 6b) that supports the lower end surface Wc of the workpiece W to be measured, and a cylindrical side surface 6c that positions the workpiece W to be measured. The support surface 6b is a surface perpendicular to the reference axis A, and the center of the support surface 6b is on the reference axis A.

  Note that it is very difficult to align the axis Wb of the workpiece W to be measured with the center of the support surface 6b. This is because, in order to increase productivity, it is necessary to provide a gap G between the side surface 6c of the recess 6a and the outer peripheral surface of the workpiece W to facilitate the installation work of the workpiece W to be measured. is there.

  When measuring roundness or the like, the light irradiation means 2 irradiates the inner circumferential surface Wa with the light L. More specifically, the light irradiation means 2 emits light L along a direction perpendicular to the reference axis A in a direction from the reference axis A toward the inner peripheral surface Wa. Therefore, the light L is irradiated only on a portion (inner peripheral surface Wa1) at a predetermined position in the reference axis A direction on the inner peripheral surface Wa. The light L is laser light in the present embodiment, but is not limited to this as long as it can be imaged by the imaging means 3.

  As shown in FIG. 2A, when viewed in a direction along the reference axis A, the light irradiation means 2 simultaneously irradiates the light L radially in all directions. Further, as shown in FIG. 2B, the light irradiation means 2 includes a laser beam emitting unit 2a, a prism 2b that reflects the laser beam La emitted from the laser beam emitting unit 2a, and a laser beam emitting unit 2a. It has a colorless and transparent cylindrical body 2c for connecting the prism 2b.

  The imaging means 3 forms an image data by imaging the inner peripheral surface Wa (Wa1) irradiated with the light L, and is constituted by a CCD camera, for example. Note that the center of the field of view of the imaging means 3 is on the reference axis A.

  The light L emitted from the light irradiation means 2 toward the inner peripheral surface Wa (Wa1) hits the inner peripheral surface Wa (Wa1) and is reflected. Therefore, in the image data formed by the imaging unit 3, as shown in FIG. 3A, a bright portion B based on the reflected light is formed in an annular shape.

  The computing means 4 computes the roundness of the inner peripheral surface Wa (Wa1) based on the image data formed by the imaging means 3, and is constituted by, for example, a microcomputer or a personal computer. Next, the calculation method of the calculation means 4 will be described.

  In the image data shown in FIG. 3A, the outer peripheral edge Ba of the bright part B is considered to be a position where the inner peripheral surface Wa (Wa1) actually exists. Therefore, first, the position of the center of gravity of the circle formed by the outer peripheral edge Ba is obtained, and the position of the center of gravity is set as the position of the center C of the circle formed by the outer peripheral edge Ba (center of the inner peripheral surface Wa1). Then, the distance from the position of the center C to the outer peripheral edge Ba (measured value R of the radius) is measured from a predetermined circumferential position (0 °) to 360 ° for each predetermined angle. Then, the difference between the maximum value and the minimum value of the measured radius values R is calculated as the roundness.

  Further, a value obtained by subtracting the design value (reference value) of the radius of the inner peripheral surface Wa from the measured radius measurement value R is calculated as a deviation.

  Note that the actual measured radius R for 360 ° at this time is all recorded and can be used as two-dimensional shape data. This can be used as three-dimensional inner diameter data in consideration of the reference axis A (Z axis) direction.

  By repeating the image data formation by the series of image pickup means 3 and the calculation by the calculation means 4 at a predetermined pitch in the direction of the reference axis A, the roundness and the roundness at every predetermined pitch in the direction of the reference axis A can be obtained. Calculate the deviation. More specifically, each of the portions Wa1, Wa2, Wa3,..., Wa (N-2), Wa (N-1), WaN at predetermined pitches in the reference axis A direction on the inner peripheral surface Wa. Calculate roundness and the like.

  The calculated roundness and deviation are displayed on the display means 7 such as a monitor. When displaying the deviation at a predetermined position in the direction of the reference axis A, for example, as shown in FIG. 5, a perfect circle E as a reference (with zero deviation at all circumferential positions) is drawn. On the other hand, the deviation F for each circumferential position is displayed (two-dimensional display). Furthermore, as shown in FIG. 9, the deviation or the measured radius value R at a position for each predetermined pitch in the direction of the reference axis A can be displayed three-dimensionally as a bird's eye view of a cylinder. In this case, a region Pa having a small deviation (close to a perfect circle), a region Pb having a large deviation (away from the perfect circle), and a region Pc having a deviation between the region Pa and the region Pb may be displayed in different colors. it can. For example, the area Pa can be green, the area Pb can be red, and the area Pc can be yellow.

  In addition, cylindricity that is a three-dimensional roundness is obtained from the roundness of each of the inner peripheral surfaces Wa1, Wa2, Wa3,..., Wa (N-2), Wa (N-1), and WaN. This may be displayed on the display means 7. Further, the centers C (C1, C2, C3... C (N-2), Wa (N-2), Wa (N-1), WaN of the inner peripheral surfaces Wa1, Wa2, Wa3,. The degree of coaxiality can be calculated from C (N−1), CN), and this may be displayed on the display means 7.

  As described above, the roundness measuring apparatus 1 calculates the roundness and the deviation for each predetermined pitch in the direction of the reference axis A, but the predetermined pitch can be arbitrarily fine. For example, if the deviation is accurately measured to form plane shape data, and the plane shape data is three-dimensionalized at a 1/100 mm pitch, three-dimensional shape data can be obtained. It can be applied as an original shape measuring instrument. Of course, even in this case, the measurement pitch is not limited to 1/100 mm pitch, and may be further reduced to 1/1000 mm pitch and 1/10000 mm pitch, or vice versa. It can be measured by pitch.

  In order to stabilize the positional relationship between the light irradiation means 2 and the imaging means 3, it is preferable to arrange three or more connecting members 8 at equal intervals in the circumferential direction of the reference axis A. However, when the connecting member 8 is made of a non-transparent material, the reflected light from the inner circumferential surface Wa is blocked, and therefore, as shown in FIG. S occurs. As shown in FIG. 4A, when three connecting members 8 are arranged at equal intervals in the circumferential direction, three radii cannot be measured due to the lack S of the bright part B. The diameter D cannot be obtained.

  On the other hand, as shown in FIG. 4B, when four connecting members 8 are arranged at equal intervals in the circumferential direction, the radius that cannot be measured due to the lack S of the bright portion B is Although four radii that cannot be measured correspond to two diameters D, the number of diameters D that cannot be obtained is two. Therefore, when it is assumed that the roundness measuring apparatus 1 determines the diameter D, it is preferable that four connecting members 8 are arranged at equal intervals in the circumferential direction. Here, for the sake of easy understanding, the description has been made assuming that one radius cannot be measured by one missing portion S of the bright portion B. Strictly speaking, the size and the radius of the missing portion S are changed every time. The number of radii that cannot be measured differs depending on whether the measurement is performed.

  By the way, if the axis Wb of the inner peripheral surface Wa of the workpiece W to be measured is coaxial or parallel to the reference axis A, theoretically, an accurate roundness can be obtained by the above-described calculation, but as shown in FIG. When the axis Wb of the inner peripheral surface Wa is inclined with respect to the reference axis A, an accurate roundness cannot be obtained only by the above calculation.

  This is because the roundness of the inner peripheral surface Wa has to be measured in a cross section in a direction perpendicular to the axis Wb of the inner peripheral surface Wa of the workpiece W to be measured, whereas the roundness measuring device 1 measures it. This is because the roundness of the inner peripheral surface Wa is measured based on a cross section (image data) in a direction perpendicular to the reference axis A.

  For this reason, when it is detected that the axis Wb of the inner peripheral surface Wa is tilted with respect to the reference axis A, the calculation means 4 determines the axis Wb of the inner peripheral surface Wa with respect to the reference axis A. The roundness may be corrected based on the inclination angle θ.

  The fact that the axis Wb of the inner peripheral surface Wa is inclined with respect to the reference axis A can be detected from the result of obtaining the coaxiality. For example, in FIG. 6, the inclination angle θ between the reference axis A and the straight line connecting the two points of the center C1 of the inner peripheral surface Wa1 and the center CN of the inner peripheral surface WaN is the reference axis of the axis Wb of the inner peripheral surface Wa. Detected as slope with respect to A.

  A method for correcting the roundness based on the inclination angle θ of the axis Wb of the inner peripheral surface Wa with respect to the reference axis A will be described below with a specific example.

  As a specific example, consider a case where the level (height) in the direction of the reference axis A is measured at a predetermined pitch (here, 1 mm) between 0 mm and 400 mm.

  First, the master work MW is measured. The master workpiece MW is a workpiece formed for correction, and the inner circumferential surface Wa has a substantially circular cross section, and the axis Wb is substantially perpendicular to the lower end surface Wc. ing. The calculation means 4 calculates | requires the position of the center C of the cross section of the internal peripheral surface Wa of the master workpiece MW for every 1 mm between 0 mm-400 mm of the direction of the reference axis A similarly to the above.

  Specifically, as shown in FIG. 7, the reference axis A is the Z axis of coordinates, and the position (Xm, Ym) of the center C of the transverse section (cross section perpendicular to the Z axis) of the inner peripheral surface Wa is calculated. And remember. For easy understanding, in this specific example, the coordinates (Xm, Ym) of the center C of the cross section of the inner peripheral surface Wa of the master work MW are all (0.00, 0.00).

  Next, the workpiece W to be measured is measured. The calculation means 4 is the position of the center C of the transverse section (cross section perpendicular to the Z axis) of the inner peripheral surface Wa of the workpiece W to be measured, in the same manner as described above, every 1 mm between 0 mm and 400 mm in the direction of the reference axis A. Ask for.

  Then, a value obtained by subtracting the XY coordinate value (0.00, 0.00) of the center C of the master workpiece MW from the obtained XY coordinate value of the center C is calculated, and the coordinates of the center C of the workpiece W to be measured are calculated. Store as (Xw, Yw).

  In other words, here, the calculation means 4 has the axis Wb (the inner circumferential surface Wa of the workpiece W to be measured with respect to the position on the vertical plane (the XY coordinate plane or a plane parallel thereto) with respect to the reference axis A (Z axis). The position (Xw, Yw) of the center C) is calculated on the basis of the position (Xm, Ym) of the axis Wb (center C) of the cylindrical inner peripheral surface Wa in the master work MW.

  As shown in FIG. 7, when Z = 0, (Xw, Yw) = (− 1.00,0.00), and when Z = 400, (Xw, Yw) = (1.00,0.00 ). Since Z = 0 and Z = 400 and the value of Yw is 0.00, the axis Wb of the workpiece W to be measured is inclined with respect to the reference axis A (Z axis) on the XZ coordinate plane. FIG. 8 shows the calculation result as a graph. As can be understood from FIG. 8, when the inclination angle of the axis Wb with respect to the reference axis A (Z axis) is θ, tan θ = 2.00 / 400, and therefore the inclination angle θ = arctan (2.00 / 400). The inclination angle θ is calculated from this equation.

In other words, here, the calculation means 4 has the axis Wb (center C) of the workpiece W to be measured on a different plane in the plane perpendicular to the reference axis A (Z axis) (the XY coordinate plane or a plane parallel thereto). That is, the inclination angle θ is calculated based on the position (Xw, Yw).

  When the axis Wb of the workpiece W to be measured is inclined with respect to the reference axis A (Z axis) on the XZ coordinate plane, the workpiece W to be measured formed by the imaging means 3 as shown in FIG. The bright portion B of the image data on the inner circumferential surface Wa is an elliptical shape having a long axis in the X-axis direction. As can be seen from the relationship shown in FIG. 6, if the radius in the X-axis direction to be obtained is Rr, the relationship is Rr = Ra × cos θ with respect to the radius Ra in the X-axis direction calculated based on the image. The radius Rr is obtained from the angle θ and the radius Ra. The roundness can be obtained from the radius Rr in the same manner as described above. As a result, the calculation means 4 corrects the roundness based on the inclination angle θ of the axis Wb of the workpiece W to be measured with respect to the reference axis A (Z axis).

  The roundness measuring apparatus 1 configured as described above can enjoy the following effects.

  Since the roundness and the like of the inner peripheral surfaces Wa1, Wa2,... WaN are calculated based on the image data of the reflected light around the inner peripheral surfaces Wa1, Wa2,. There is no need to rotate W. Therefore, an axis alignment operation can be made unnecessary. And the light irradiation means 2 moves inside the inner peripheral surface Wa, and can capture an image of reflected light from each part of the inner peripheral surfaces Wa1, Wa2,... Thereby, the roundness can be measured based on this image, and further, the cylindricity and the coaxiality which can be said to be a three-dimensional version of the roundness can be measured. Moreover, since the light irradiation means 2 and the imaging means 3 move, maintaining a fixed distance, the image of the internal peripheral surface Wa imaged with the imaging means 3 becomes a fixed magnitude | size. That is, there is no change in the size of the image due to a change in the distance between the light irradiation means 2 and the imaging means 3. Further, by correcting the roundness based on the inclination angle θ of the axis Wb of the inner peripheral surface Wa with respect to the reference axis A, the measurement accuracy of the roundness is improved.

  Further, if the inner circumferential surface Wa whose roundness is to be measured falls within the field of view of the imaging means 3, no matter where the axis Wb of the workpiece W to be measured is located in the direction perpendicular to the reference axis A, Circularity can be measured. Therefore, it is not necessary to position the workpiece W in a direction perpendicular to the reference axis A with high accuracy.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical idea. For example, in the above embodiment, the workpiece W to be measured is arranged so that the axis Wb is in the vertical direction, and the light irradiation means 2 and the imaging means 3 move along the vertical direction. The measurement workpiece W may be arranged so that the axis Wb is in the horizontal direction, and the light irradiation means 2 and the imaging means 3 may be moved along the horizontal direction.

  Moreover, in the said embodiment, although the light irradiation means 2 and the imaging means 3 maintained the fixed distance by the connection by the connection member 8, even if it is not connected, the light irradiation means 2 and the imaging means 3 are constant. It is sufficient if the distance can be maintained. For example, apart from the moving means 5 (second moving means) for moving the imaging means 3, a first moving means for moving the light irradiation means 2 is provided, and the light irradiation means 2 and the imaging means 3 are respectively covered. It may be introduced from the opening on the opposite side of the measurement workpiece W and moved in synchronization with the measurement.

  Moreover, you may make the positional relationship of the laser beam emission part 2a and the prism 2b in the light irradiation means 2 of the said embodiment reverse.

  Moreover, in the said embodiment, when the calculating means 4 correct | amends roundness based on inclination-angle (theta), the position (Xw, Yw) of the to-be-measured workpiece W is based on the position (Xm, Ym) of the master workpiece MW. Was calculated. However, the present invention is not limited to this, and the position (Xw, Yw) of the workpiece W to be measured is determined as the master workpiece MW even when the calculation means 4 does not correct the roundness based on the inclination angle θ. The position (Xm, Ym) may be used as a reference.

DESCRIPTION OF SYMBOLS 1 Roundness measuring apparatus 2 Light irradiation means 3 Imaging means 4 Calculation means 5 Moving means A Reference axis L Light MW Master work W Work to be measured Wa Inner peripheral surface Wb Axis line θ Inclination angle

Claims (6)

Light irradiation means for illuminating the cylindrical inner peripheral surface of the workpiece to be measured, imaging means for imaging the inner peripheral surface to form image data, and a perfect circle on the inner peripheral surface based on the image data In a roundness measuring device provided with a calculation means for calculating the degree,
A reference axis extending in the direction of the axis of the inner peripheral surface;
A first moving means for moving the light irradiation means illuminating the inner peripheral surface along the direction of the reference axis on the inner side of the inner peripheral surface;
Second moving means for moving the imaging means along the direction of the reference axis,
An apparatus for measuring roundness, wherein the light irradiation means and the imaging means are configured to move while maintaining a certain distance.   The roundness measuring device according to claim 1, wherein when viewed in a direction along the reference axis, the light irradiation unit simultaneously emits light radially.   The roundness measuring apparatus according to claim 1, wherein a connecting member that connects the light irradiation unit and the imaging unit is provided, and the second moving unit also serves as the first moving unit.   The roundness measurement apparatus according to claim 1, wherein the calculation unit corrects the roundness based on an inclination angle of the axis with respect to the reference axis.   5. The roundness measuring apparatus according to claim 4, wherein the calculation unit calculates the inclination angle based on a position of the axis on a different plane among the planes perpendicular to the reference axis.   The calculation means calculates the position of the axis with respect to the position on the vertical plane with respect to the reference axis with reference to the position of the axis of the cylindrical inner peripheral surface of the master work. The roundness measuring apparatus according to any one of?