JP2017072546A - Inner diameter measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inner diameter measurement device that can highly accurately measure an inner diameter of an opening part without need for positioning a measurement head to the opening part using a positioning guide.SOLUTION: An inner diameter measurement device 1 of the present invention comprises, more specifically, a data processing unit 24 that puts together, as one data group, many measurement values measured by a measurement head 15 as causing a mirror angle variable device 18 to change a laser irradiation angle so as to be across an axis orthogonal direction orthogonal to a rotation axis of the measurement head 15; acquires the data group every a unit rotation angle, respectively as causing a rotation drive unit 7 to rotate the measurement head 15; selects each minimum value from each data group, respectively; and calculates an inner diameter of an opening part 2 on the basis of the plurality of minimum values. The opening part 2 can thus be accurately measured without requiring a positioning guide for positioning the measurement head 15 with respect to the opening part 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inner diameter measuring device for measuring the inner diameter of a circular opening.

  A conventional inner diameter measuring device generally includes a measuring head for measuring the distance to the inner wall surface of the opening, a positioning guide for positioning the measuring head with respect to the opening, and the measuring head with respect to the inner wall surface of the opening. And a rotation drive unit that relatively rotates. Then, after positioning the measurement head with respect to the opening by the positioning guide, the distance from the measurement head to the inner wall surface of the opening is measured at a plurality of locations while rotating the measurement head by the rotation drive unit. The center point in the radial direction of the opening and its inner diameter are calculated from the measured values. Therefore, the positioning guide aligns the sensor reference point located on the rotation axis of the measurement head with the substantially radial center point of the opening, and also tilts the axial direction (rotation axis) of the measurement head with respect to the axial direction of the opening. Are provided to correct. The positioning guide is formed in a cylindrical shape so as to surround the outer periphery of the measuring head, and has an outer diameter slightly smaller than the inner diameter of the opening. Then, when positioning the measurement head with respect to the opening by the positioning guide, the measurement head is positioned with respect to the opening while being mounted on the outer periphery of the measurement head and inserted into the opening.

  However, since the conventional inner diameter measuring device needs to have a positioning guide corresponding to the inner diameter of the opening, the positioning guide or the entire measuring head must be replaced every time an opening having a different inner diameter is measured. , Work efficiency cannot be achieved. Further, since the positioning guide is inserted into the opening while contacting the inner wall surface to position the measuring head relative to the opening, the positioning guide may damage the inner wall surface of the opening. Measures to prevent it are necessary. In addition, the outer wall surface of the positioning guide may be worn or damaged, and an appropriate clearance cannot be maintained between the outer wall surface of the positioning guide and the inner wall surface of the opening, allowing excessive tilting of the measuring head. As a result, the reliability of the measured value decreases.

  Therefore, as a conventional technique for measuring the inner diameter of an opening without providing a positioning guide, Patent Document 1 discloses a distance sensor that irradiates a measurement target with a laser, detects reflected light, and calculates a distance to a measurement point. , Integrating a separation unit that separates light from the distance sensor into a plurality of units, a rotating unit that relatively rotates the distance sensor and the measurement target, and a measurement result of distances to a plurality of measurement points obtained from the distance sensor There is disclosed a shape measuring device that includes a data processing unit and calculates an inclination angle of a measuring device based on measurement results of a plurality of cross sections having different depth directions of the tube body, thereby calculating an inner diameter of the tube body.

JP2015-17811A

  However, the shape measuring apparatus according to Patent Document 1 has the following problems. In this shape measuring device, the center points O1 and O2 of each cross-sectional shape are calculated from the measurement results of a plurality of cross-sections having different depth directions, and the inclination of the central axis of the inner surface shape measuring device is calculated based on the calculation results. θ is calculated, and finally the inner diameter of the tube is calculated by correcting the angle with respect to actual measurement data. For this reason, since this calculation method requires a plurality of calculation processes, there is a possibility that an error may increase, and it is difficult to accurately measure the inner diameter of the tube body.

  The present invention has been made in view of the above points, and provides an inner diameter measuring device that can accurately measure the inner diameter of the opening without the need to position the measuring head with respect to the opening using a positioning guide. The purpose is to do.

  In order to solve the above-mentioned problem, the invention of claim 1 is an inner diameter measuring device for measuring the inner diameter of a circular opening, which irradiates a laser toward the inner wall surface of the opening and reflects the reflected light. A measurement head for measuring the distance from the reference point to the inner wall surface by detecting, a rotation driving unit for rotating the measurement head around the rotation axis relative to the inner wall surface of the opening, and the measurement An angle variable device that changes an irradiation angle of a laser irradiated from the reference point located on the rotation axis of the head with respect to an axis orthogonal direction orthogonal to the rotation axis of the measurement head, and laser irradiation by the angle variable device While changing the angle so as to straddle the direction perpendicular to the axis, a large number of measurement values measured by the measurement head are made into one data group, and the measurement head is rotated by the rotation drive unit. A data processing unit that obtains each unit rotation angle, selects a minimum value from each data group, and calculates an inner diameter of the opening based on the plurality of minimum values. It is what.

  In the first aspect of the present invention, in particular, in the data processing unit, the number of laser beams measured by the measurement head while changing the laser irradiation angle across the axis orthogonal direction orthogonal to the rotation axis of the measurement head by the angle variable device. Are obtained for each unit rotation angle of the measuring head, and a minimum value is selected from each data group, and based on the plurality of minimum values, the aperture values of the openings are obtained. The inner diameter can be calculated. This eliminates the need for a positioning guide for positioning the measurement head with respect to the opening, calculates the inclination angle of the axial direction (rotation axis) of the measurement head with respect to the axial direction of the opening, and corrects the angle. Therefore, the inner diameter of the opening can be measured with high accuracy.

FIG. 1 is a schematic diagram of an inner diameter measuring apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a state in which the measuring head of the inner diameter measuring apparatus is arranged in the opening and measures the inner diameter of the opening. FIG. 3 is a schematic diagram showing a distance sensor and a mirror angle varying device of the present inner diameter measuring device. FIG. 4 is a diagram for explaining a method of calculating the inner diameter of the opening in the data processing unit.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to FIGS.
An inner diameter measuring apparatus 1 according to an embodiment of the present invention measures an inner diameter of an opening 2 provided in a workpiece W, as shown in FIG. The workpiece W is formed in a cylindrical shape, and a circular opening 2 along the axial direction is penetrated through a central portion in the radial direction.

  As shown in FIGS. 1 and 2, the inner diameter measuring device 1 includes a mounting table 5 on which a workpiece W is mounted, and a columnar support 6 that extends upward from an end of the mounting table 5. On the side wall of the support 6, a slide rail 8 extending in the vertical direction is projected. A rotation drive unit 7 that rotates the measurement head 15 is connected to the side wall of the support 6 via a slide rail 8. The rotation drive unit 7 can be raised and lowered with respect to the support 6 along the slide rail 8 by driving the lifting device 10. A shaft portion 9 extending downward is connected to the lower end of the rotation driving portion 7. A measuring head 15 is connected to the lower end of the shaft portion 9. The shaft 9 is rotated by the drive of the rotation driving unit 7, and the measurement head 15 is rotated around the rotation axis thereof, that is, the axis of the shaft 9. In the present embodiment, the measurement head 15 is rotated at a set angle pitch (1 ° pitch in the present embodiment) by driving of the rotation driving unit 7. The rotation drive unit 7 includes an angle encoder 16 that detects a relative rotation angle of the measurement head 15 with respect to the inner wall surface 2 a of the opening 2 of the workpiece W. The lifting device 10, the rotation driving unit 7, and the angle encoder 16 are electrically connected to the control unit 25, respectively.

  The measurement head 15 includes a small-diameter head portion 15a located on the upper side and a large-diameter head portion 15b located on the lower side with a larger diameter than the small-diameter head portion 15a. Naturally, the large-diameter head portion 15b has a smaller diameter than the opening 2 of the workpiece W. Referring also to FIG. 3, in the measuring head 15, a laser is irradiated from the outer wall surface of the large-diameter head portion 15 b toward the inner wall surface 2 a of the opening 2 of the workpiece W, and the reflected light is detected. A distance sensor 17 for measuring a distance from a reference point (black point in FIG. 2, FIG. 3 and point O1 in FIG. 4) located on the rotation axis of the measuring head 15 to the inner wall surface 2a, and a laser emitted from the distance sensor 17 And a mirror angle varying device 18 that is an angle varying device that changes an irradiation angle with respect to an axis orthogonal direction (radial direction) orthogonal to the rotation axis (axial direction) of the measuring head 15.

  As shown in FIG. 3, the distance sensor 17 includes a light projecting / receiving unit 20 that measures the distance to the surface to be measured by detecting the reflected light from the surface to be measured by irradiating the laser. The mirror angle varying device 18 is disposed away from the light projecting / receiving unit 20 and directs the laser from the light projecting / receiving unit 20 from the outer wall surface of the large-diameter head unit 15b of the measuring head 15 to the inner wall surface 2a of the opening 2 of the workpiece W. A galvanometer mirror 21 that is bent in this manner, and a variable angle main body 19 that swings the galvanometer mirror 21 within a range of a predetermined angle around a bending point (black point in FIG. 3) with the galvanometer mirror 21 of the laser. . Then, the laser from the light projecting / receiving unit 20 of the distance sensor 17 is bent by the galvano mirror 21 and irradiated toward the inner wall surface 2a of the opening 2 of the workpiece W, and the reflected light from the inner wall surface 2a is projected and received. By detecting at 20, the projection point that becomes the reference point of the laser located on the rotation axis of the measuring head 15, that is, the bending point of the laser with the galvanometer mirror 21 (the black point in FIGS. 2 and 3 and the point in FIG. 4). The distance from O1) to the inner wall surface 2a of the opening 2 of the workpiece W is measured. In the present embodiment, the light projecting / receiving unit 20 that is the distance sensor 17 is disposed in the measurement head 15, but may be disposed outside the measurement head 15.

  The mirror angle varying device 18 is configured so that the galvano mirror 21 is bent by a variable angle main body 19 from a reference angle (an angle at which the laser bending angle from the light projecting / receiving unit 20 is 90 °) to the laser galvano mirror 21 (see FIG. 3), the laser beam from the light projecting / receiving unit 20 is bent by the galvano mirror 21 to the axis orthogonal direction orthogonal to the rotation axis of the measuring head 15 by swinging in a predetermined direction within a range of ± α °. And configured to be irradiated with an inclination within a range of ± α °. The swing angle α ° needs to be set larger than the estimated value of the inclination angle θ of the measuring head 15 in the axial direction (rotating axis) with respect to the axial direction of the opening 2. The distance sensor 17 (projecting / receiving unit 20) and the mirror angle varying device 18 (angle varying main body 19) are electrically connected to the control unit 25, respectively. The control unit 25 controls starting and stopping of each component device.

  The light projecting / receiving unit 20 of the distance sensor 17 is electrically connected to the data processing unit 24. The data processing unit 24 calculates the radial center point O2 of the opening 2 of the workpiece W and its inner diameter based on the measurement result from the distance sensor 17. The calculation method will be described in detail later.

Next, the operation of the inner diameter measuring apparatus 1 according to the embodiment of the present invention will be described.
First, the workpiece W is positioned and mounted on the mounting table 5 of the inner diameter measuring apparatus 1 so that the opening 2 faces upward. In the following description, it is assumed that the axial direction (rotating axis) of the measuring head 15 is inclined at an inclination angle θ with respect to the axial direction of the opening 2 of the workpiece W.

  Next, the lifting device 10 is driven by a signal from the control unit 25, and the measuring head 15 is inserted into a predetermined position in the opening 2 of the workpiece W. Subsequently, the laser is emitted from the distance sensor 17 of the measuring head 15 toward the inner wall surface 2 a of the opening 2 of the workpiece W by a signal from the control unit 25. Subsequently, the variable angle main body 19 is driven by a signal from the control unit 25, and the galvano mirror 21 is swung from -α ° to + α ° (or + α ° to -α °). While changing the laser irradiation angle from −α ° to + α ° (or + α ° to −α °) so as to cross the axis orthogonal direction orthogonal to the rotation axis of the measurement head 15, the distance sensor 17 causes the measurement head 15 to move. A number of distances from the projection point (black point in FIGS. 2 and 3 and point O1 in FIG. 4), which is the reference point of the laser located on the rotation axis, to the inner wall surface 2a of the opening 2 of the workpiece W are measured. The measured many measured values are transmitted to the data processing unit 24 as one data group.

Next, when the control unit 25 detects the end of the measurement at this position, the rotation drive unit 7 is driven by the signal from the control unit 25 and the measurement head 15 rotates relative to the inner wall surface 2 a of the opening 2. To do. Subsequently, when the angle encoder 16 detects the rotation angle of the measurement head 15, for example, a rotation angle of 1 °, the detection signal is transmitted to the rotation drive unit 7 via the control unit 25, and the rotation of the measurement head 15 is temporarily stopped. To do. Subsequently, the angle variable main body 19 is driven again by a signal from the control unit 25, and the galvano mirror 21 is swung from -α ° to + α ° (or + α ° to -α °), so that the galvano mirror 21 is driven. The measurement head is measured by the distance sensor 17 while changing the laser irradiation angle from −α ° to + α ° (or + α ° to −α °) so as to straddle the axis orthogonal direction orthogonal to the rotation axis of the measurement head 15. A number of distances from the 15 laser projection points (reference points) to the inner wall surface 2a of the opening 2 of the workpiece W are measured. The measured many measured values are transmitted to the data processing unit 24 as one data group.
Thereafter, the measurement operation described above is repeated for each unit rotation angle, for example, every rotation angle of 1 °, while rotating the measurement head 15 once.

  That is, the rotation angle of the laser from the galvanometer mirror 21 is determined by driving the variable angle main body 19 for each unit rotation angle, for example, every rotation angle of 1 °, while rotating the measurement head 15. The distance sensor 17 changes the workpiece from the laser projection point (reference point) of the measuring head 15 while changing from -α ° to + α ° (or + α ° to -α °) so as to straddle the direction perpendicular to the axis perpendicular to the workpiece. A number of distances to the inner wall surface 2a of the W opening 2 are measured. Then, data groups (360 pieces) measured at every rotation angle of 1 ° are transmitted to the data processing unit 24, respectively.

  Referring to FIG. 4, the data processing unit 24 acquires 360 data groups measured for each unit rotation angle (rotation angle 1 °) when the measurement head 15 is rotated once (360 °). From the 360 data group, the minimum value of the distance from the projection point (point O1 in FIG. 4) which is the laser reference point of the measuring head 15 to the inner wall surface 2a of the opening 2 of the workpiece W ( L1, L2... L359, L360) are selected. Subsequently, the projection point O1 corresponding to each of the selected 360 minimum values (L1, L2,... L359, L360), that is, the minimum values (L1, L2,... L359, L360) is defined as the origin. Based on 360 coordinates (X1, Y1), (X2, Y2)... (X359, Y359), (X360, Y360), the measurement trajectory A cross-sectional shape along the radial direction of the opening 2 is obtained, and the radial center point O2 and the inner diameter of the opening 2 of the workpiece W are calculated. As a result, the projection point O1, which is the laser reference point of the measuring head 15, does not coincide with the radial center point O2 of the opening 2 of the workpiece W, and the axial direction (rotating axis) of the measuring head 15 is the opening 2 of the opening 2. Even if it is inclined at an inclination angle θ with respect to the axial direction, the radial center point O2 of the opening 2 of the workpiece W and its inner diameter can be accurately measured.

  In the present embodiment, the measurement head 15 is rotated once (360 °) to calculate the radial center point O2 of the opening 2 of the workpiece W and its inner diameter, which is the best mode. The head 15 is rotated 180 °, the minimum value is selected from each of the 180 data groups, and the radial center point O2 of the opening 2 of the workpiece W and the inner diameter thereof are determined based on the selected 180 minimum values. You may make it calculate.

  As described above, the inner diameter measuring apparatus 1 according to the embodiment of the present invention, in particular, the measuring head 15 of the laser irradiated from the projection point O1, which is the reference point located on the rotation axis of the measuring head 15. The mirror angle varying device 18 that changes the irradiation angle with respect to the axis orthogonal direction (radial direction) orthogonal to the rotation axis (axial direction) of the laser, and the laser irradiation angle by the mirror angle varying device 18 is set as the rotation axis of the measuring head 15. A large number of measurement values measured by the measurement head 15 are changed into one data group while changing so as to cross the orthogonal axis orthogonal directions, and the data group is converted into a unit while the measurement head 15 is rotated by the rotation drive unit 7. A data processing unit 24 that obtains each rotation angle, selects a minimum value from each data group, and calculates the inner diameter of the opening 2 based on the plurality of minimum values. .

  Thereby, in the inner diameter measuring apparatus 1 according to the embodiment of the present invention, the positioning head is not used to position the measuring head 15 with respect to the opening 2 of the workpiece W, and as a result, the laser reference of the measuring head 15 is obtained. The light projecting point O1, which is a point, does not coincide with the radial center point O2 of the opening 2 of the workpiece W, and the axial direction (rotating axis) of the measuring head 15 is inclined at an inclination angle θ with respect to the axial direction of the opening 2. Even in this case, the radial center point O2 of the opening 2 of the workpiece W and the inner diameter thereof can be measured with high accuracy. As described above, the inner diameter measuring apparatus 1 according to the embodiment of the present invention does not require a positioning guide for positioning the measuring head 15 with respect to the opening 2 of the workpiece W, and therefore measures the openings 2 having different inner diameters. It is not necessary to replace the positioning guide or the entire measuring head each time, and the work efficiency can be improved.

  In addition, since the inner diameter measuring apparatus 1 according to the embodiment of the present invention does not require a positioning guide, damage to the inner wall surface of the opening 2 due to the positioning guide can be prevented, and the outer wall surface of the positioning guide can be prevented. The problem of positioning failure of the measuring head 15 due to wear or damage can be solved. Furthermore, in the inner diameter measuring apparatus 1 according to the embodiment of the present invention, the inclination angle θ of the axial direction (rotating axis) of the measuring head 15 with respect to the axial direction of the opening 2 of the workpiece W is calculated and angle correction is performed. Thus, the measurement error of the inner diameter of the opening 2 can be kept to a minimum.

  DESCRIPTION OF SYMBOLS 1 Inner diameter measuring device, 2 Opening part, 2a Inner wall surface, 7 Rotation drive part, 15 Measuring head, 17 Distance sensor, 18 Mirror angle variable apparatus (angle variable apparatus), 24 Data processing part

Claims (1)

An inner diameter measuring device for measuring the inner diameter of a circular opening,
A measuring head that measures the distance from the reference point to the inner wall surface by irradiating a laser toward the inner wall surface of the opening and detecting the reflected light;
A rotation drive unit for rotating the measurement head around its rotation axis relative to the inner wall surface of the opening;
An angle variable device that changes an irradiation angle of a laser irradiated from the reference point located on the rotation axis of the measurement head with respect to an axis orthogonal direction orthogonal to the rotation axis of the measurement head;
While changing the laser irradiation angle by the angle variable device so as to straddle the direction perpendicular to the axis, a large number of measurement values measured by the measurement head are used as one data group, and the data group is used as the measurement head. A data processing unit that obtains each unit rotation angle while rotating by the rotation driving unit, selects a minimum value from each data group, and calculates an inner diameter of the opening based on the plurality of minimum values When,
An inner diameter measuring device comprising:

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