WO2014010260A1

WO2014010260A1 - X-ray diffraction measurement device and x-ray diffraction measurement system

Info

Publication number: WO2014010260A1
Application number: PCT/JP2013/051603
Authority: WO
Inventors: 洋一丸山
Original assignee: パルステック工業株式会社
Priority date: 2012-07-09
Filing date: 2013-01-25
Publication date: 2014-01-16
Also published as: JP5708582B2; JP2014016220A

Abstract

An x-ray diffraction measurement device houses, in a case (10), an x-ray emitter (20), a mobile and rotatable table (30), an imaging plate (31) which is attached to the table (30), and a laser detection device (50). X-rays are projected from the x-ray emitter (20) at an x-ray measurement object, a diffraction ring is formed upon the image plate (31) by diffracted x-rays which are emitted from the measurement object, the shape of the diffraction ring which is formed upon the imaging plate (31) is read by the laser detection device (50), and residual stress of the measurement object is detected. A front face wall (11) and a bottom face wall (14) of the case (10) intersect, and the x-ray emitter (20) is positioned such that, when the bottom face wall (14) and the front face wall (11) are respectively brought into contact with a horizontal face and a vertical face of an L-shaped measurement object, the x-rays are emitted near a corner part of the horizontal face.

Description

X-ray diffraction measurement device and X-ray diffraction measurement system

The present invention relates to an X-ray diffraction measurement apparatus for irradiating a measurement object with X-rays, forming a diffraction ring on the surface of an imaging plate by X-rays diffracted by the measurement object, and reading the formed diffraction ring, The present invention relates to an X-ray diffraction measurement system that measures a residual stress of an object to be measured using a diffraction ring that includes a diffraction measurement apparatus and is read by an X-ray diffraction measurement apparatus.

Conventionally, the residual stress of a measurement object is often measured by X-ray diffraction. In the field of residual stress measurement, an X-ray diffraction measurement apparatus capable of reducing the size of the apparatus and shortening the X-ray irradiation time is disclosed, for example, in Patent Document 1 below. In this X-ray diffractometer, the measuring device is arranged at a desired position on the rail as a measurement object, and a predetermined incident angle (30 in a plane perpendicular to the upper surface of the rail, including the extending direction of the rail). X-rays radiated on the top surface of the rail at ~ 45 degrees and diffracted on the top surface of the rail (hereinafter, X-rays diffracted by such an object to be measured are referred to as diffracted X-rays) have photosensitivity. Light is received by the imaging plate, and an annular X-ray diffraction image (hereinafter, this annular X-ray diffraction image is simply referred to as a diffraction ring) is formed on the imaging plate. Then, the imaging plate is detached from the measuring device and attached to the diffraction ring reader, and the shape of the diffraction ring formed on the imaging plate is analyzed using the cos α method, and the residual stress in the rail axis direction on the rail upper surface is analyzed. I am trying to calculate.

Japanese Patent Laid-Open No. 2005-241308

In the technical field of residual stress measurement, it is also required to measure the residual stress near the corner of a measurement object having a 90-degree cross-sectional shape, that is, a measurement object having an L-shaped cross-section. In particular, when two iron metal plates are intersected at an angle of 90 degrees and the intersecting portions are joined by welding to produce an iron part or an iron member having an L-shaped cross section, the position near the welded portion, that is, measurement It is required to measure the residual stress near the corner of the object. However, there are the following problems with respect to such a request.

First, if the measurement object is movable, it is possible to irradiate X-rays from any direction. However, if the measurement object is immovable, the diffraction ring shown in the above prior art is used. It is necessary to use a small X-ray diffractometer that is formed to measure the residual stress. However, the X-ray diffractometer shown in the above prior art measures the residual stress in the axial direction of the rail, and is not suitable for measuring the residual stress near the corner. That is, in the conventional X-ray diffraction measurement apparatus, X-rays are not accurately irradiated at a predetermined angle with respect to each surface of the measurement object at positions near the corners of the measurement object. The diffraction ring for measuring the residual stress in the vicinity of the portion cannot be formed on the imaging plate with high accuracy.

The present invention has been made in order to solve the above-mentioned problems, and the purpose of the present invention is to easily irradiate X-rays at a predetermined angle with respect to each surface of the measurement object at positions near the corners of the measurement object. To provide a small X-ray diffraction measuring apparatus that can accurately measure the residual stress near the corner of the object and can be transported to measure the residual stress near the corner of the measurement object that cannot move. It is in. Also provided is an X-ray diffraction measurement apparatus that can form a diffraction ring by X-rays on an imaging plate and can measure the shape of the diffraction ring in the same apparatus without removing the imaging plate on which the diffraction ring is formed. There is also. In the description of each constituent element of the present invention below, in order to facilitate understanding of the present invention, reference numerals of corresponding portions of the embodiments described later are shown in parentheses, but each constituent element of the present invention is described. Should not be construed as limited to the configuration of the corresponding parts indicated by the reference numerals of this embodiment.

In order to achieve the above object, the present invention is characterized in that an X-ray emitter (20) that emits X-rays toward a measurement object and a table (30) in which a through-hole that allows X-rays to pass through is formed in the center. ) And a diffraction ring which is an image of the diffracted light, having a light receiving surface for receiving the X-ray diffracted light diffracted by the measurement object while passing through the X-ray at the center. It has an imaging plate (31) for recording, a laser light source that emits laser light, and a photodetector that receives the laser light. The laser light is emitted to the light receiving surface of the imaging plate, and is emitted from the imaging plate by laser light irradiation. Detector (50) that receives received light and outputs a received light signal corresponding to the received light intensity, a rotation mechanism (47) that rotates the table around the central axis of the through hole, and X-ray emission A moving mechanism (41 to 43) for moving the table between an X-ray emission position where X-rays from the laser beam pass through the table and the imaging plate and a laser beam irradiation position where the imaging plate is irradiated with laser light from the laser detection device ) And a case (10) containing an X-ray emitter, a table, an imaging plate, a laser detector, a rotation mechanism, and a moving mechanism, and the X-ray emitted from the X-ray emitter passes through the case and is measured An X-ray diffraction measurement apparatus that irradiates an object and guides the diffracted X-rays emitted from the measurement object by irradiation of X-rays to the imaging plate through the case, and the case has a flat plate-like shape orthogonal to each other. It has 1 plane wall (14) and 2nd plane wall (11), and the optical axis of the X-rays emitted from the X-ray emitter is orthogonal to the first plane wall and the second plane wall, respectively. X-rays are included so that X-rays are emitted from a direction inclined by a first predetermined angle with respect to the second plane wall at a position near the intersection line of the first plane wall and the second plane wall. An emitter is disposed in the case, and the first plane wall is brought into contact with one plane portion of the pair of plane portions with respect to the measurement object (OB) having a pair of plane portions (hp, vp) orthogonal to each other. In addition, when the second flat wall is brought into contact with the other flat portion of the pair of flat portions, the pair of flat portions is located at a position near the intersection line of the pair of flat portions in the one or other flat portion. The X-ray from the X-ray emitter is emitted from the direction orthogonal to the intersecting line. In this case, the first predetermined angle may be in the range of 35 degrees to 55 degrees.

According to the present invention configured as described above, the X-ray configured as described above can be used even when a measurement object having a pair of plane portions orthogonal to each other, that is, an L-shaped measurement object cannot be easily moved. If the diffraction measuring device is transported and the first flat wall is brought into contact with one flat portion of the pair of flat portions and the second flat wall is brought into contact with the other flat portion of the pair of flat portions, the one Alternatively, the X-ray from the X-ray emitter is irradiated with high accuracy to a position in the vicinity of the intersection line of the pair of plane portions in the other plane portion. In addition, the X-ray emission direction is a direction inclined by a first predetermined angle with respect to the plane portion in contact with the second plane wall and is orthogonal to the intersecting line of the pair of plane portions. Therefore, X-rays can be irradiated to the positions near the corners of the L-shaped measurement object at a predetermined angle with respect to each surface of the measurement object. Thus, according to the present invention, if the shape of the diffraction ring formed on the imaging plate by the X-ray irradiation is read using the light reception signal output from the laser detector, the shape of the read diffraction ring is obtained. Therefore, it is possible to accurately measure the residual stress in the vicinity of the corner of the L-shaped measuring object, which is perpendicular to the intersecting line of the measuring object and parallel to the first plane wall. Become.

Another feature of the present invention is that the case further includes a flat inclined wall (17) that is orthogonal to the first flat wall and is inclined at a second predetermined angle with respect to the second flat wall toward the inside of the case. And when the first flat wall is brought into contact with one flat part of the pair of flat parts of the measurement object and the inclined wall is brought into contact with the other flat part of the pair of flat parts, Alternatively, a plane perpendicular to the first plane wall that includes the optical axis of the X-ray emitted from the X-ray emitter at a position in the vicinity of the intersection line of the pair of plane portions in the other plane portion is the intersection line of the pair of plane portions. X-rays from the X-ray emitter are emitted in a state intersecting at a second predetermined angle with respect to a plane orthogonal to. In this case, the second predetermined angle may be in the range of 20 degrees to 50 degrees.

According to another feature of the present invention configured as described above, the first flat wall is brought into contact with one flat portion of the pair of flat portions of the measurement object, and the inclined wall is brought into contact with the other flat portion of the pair of flat portions. If it is brought into contact with the plane part, the optical axis of the X-ray emitted from the X-ray emitter is positioned near the intersection line of the pair of plane parts in one or the other plane part of the L-shaped measurement object. The X-ray from the X-ray emitter is emitted with high accuracy in a state where the plane perpendicular to the first plane wall intersects the plane perpendicular to the intersection line of the pair of plane portions at the second predetermined angle. It will be. Therefore, in this case, not only the residual stress in the direction perpendicular to the intersection line of the pair of plane portions and parallel to the first plane wall, but also the residual stress including the residual stress component in the direction of the intersection line is measured. By calculating using the measured residual stress, the residual stress in the direction of the intersecting line can also be accurately measured.

Further, according to another feature of the present invention, the moving direction of the table by the moving mechanism may be the direction of the intersecting line between the first plane wall and the second plane wall. According to this, the case containing the X-ray emitter, the table, the imaging plate, the laser detection device, the rotation mechanism, and the moving mechanism can be formed in a long shape, and the case can be made into a simple shape, Since the components housed in the can be arranged in a compact manner, the case can be made small.

Further, another feature of the present invention is that the case is provided with a carrying handle (19). According to this, the X-ray diffraction measurement apparatus can be easily transported and moved.

Further, another feature of the present invention is that a diffraction ring erasing means (63) for erasing the diffraction ring formed on the imaging plate is further provided. According to this, the diffraction ring formed on the imaging plate can be easily deleted, and a new diffraction ring can be formed on the imaging plate, and the diffraction ring on the imaging plate by X-ray irradiation can be formed. Formation can be performed easily and repeatedly.

Another feature of the present invention is that, in addition to the X-ray diffraction measuring apparatus, the case has a flat plate-shaped first plane wall and second plane wall orthogonal to each other, and the table is controlled by controlling the rotation mechanism. While rotating and moving the table by controlling the moving mechanism, the laser detection device is controlled to irradiate the light receiving surface of the imaging plate while detecting the irradiation position, and the light reception signal from the laser detection device is input Then, a diffraction ring reading means (91, S200 to S248, S300 to S320) for reading the diffraction ring formed on the imaging plate by processing the detected irradiation position and the received light reception signal, and a pair of orthogonally crossing each other. A measurement object having a plane part is brought into contact with one plane part of the pair of plane parts and the second plane wall is paired with the pair of plane parts. Data representing a diffraction ring formed on the imaging plate by being irradiated with X-rays from the X-ray emitter in contact with the other plane portion, and using the data read by the diffraction ring reading means, Residual stress calculation for calculating the residual stress in the vicinity of the intersecting line of the pair of planar portions in the other planar portion and perpendicular to the intersecting line of the pair of planar portions and parallel to the first planar wall Means (91, S502). According to this, the residual stress in the direction orthogonal to the extending direction of the corner portion in the vicinity of the corner portion of the measurement object having the L shape and parallel to the first plane wall can be obtained with high accuracy.

Furthermore, another feature of the present invention is that the case has a flat first flat wall and a second flat wall that are orthogonal to each other, is orthogonal to the first flat wall, and is inside the case with respect to the second flat wall. In addition to the X-ray diffraction measuring apparatus having a flat inclined wall inclined in the direction at a second predetermined angle, the table is rotated by controlling the rotation mechanism, and the table is moved by controlling the moving mechanism. The laser detection device is controlled to irradiate the light receiving surface of the imaging plate while detecting the irradiation position, and the light receiving signal from the laser detecting device is inputted, and the detected irradiation position and the input light receiving signal are inputted. A diffraction ring reading means (91, S200 to S248, S300 to S320) for reading the diffraction ring formed on the imaging plate by processing, and a pair of planes orthogonal to each other The first plane wall is brought into contact with one plane portion of the pair of plane portions, and the second plane wall is brought into contact with the other plane portion of the pair of plane portions. Data representing a diffraction ring formed on the imaging plate by X-ray irradiation from the line emitter, the data read by the diffraction ring reading means, and the first plane wall on one plane part of the pair of plane parts This is data representing a diffraction ring formed on the imaging plate by X-ray irradiation from the X-ray emitter by bringing the inclined wall into contact with the other flat portion of the pair of flat portions. Using the data read by the ring reading means, the residual stress in the vicinity of the intersection line of the pair of plane portions in the one or other plane portion, which is orthogonal to the intersection line of the pair of plane portions, Residual stress in the direction parallel to the plane wall Residual stress calculation means for calculating the direction of residual stress of the fine the intersection lines in (91, S500 ~ S510) and further comprising a. According to this, it is possible to accurately obtain the extension direction of the corner portion in the vicinity of the corner portion of the measurement object having an L-shape and the residual stress in the direction orthogonal to the extension direction.

(A) is a front view of the X-ray-diffraction measuring apparatus which concerns on one Embodiment of this invention, (B) is a top view of the said X-ray-diffraction measuring apparatus, (C) is the said X-ray-diffraction measuring apparatus. It is a right view. FIG. 2 is a cross-sectional view of the X-ray diffraction measurement device viewed along line 2-2 in FIG. FIG. 3 is a cross-sectional view of the X-ray diffraction measurement device viewed along line 3-3 in FIG. FIG. 4 is a cross-sectional view of the X-ray diffraction measurement apparatus taken along line 4-4 of FIG. 1 is an overall schematic block diagram showing an X-ray diffraction measurement system including an X-ray diffraction measurement apparatus. It is a flowchart which shows the diffraction ring imaging program performed by the controller of FIG. It is a flowchart which shows the first half part of the diffraction ring reading program performed by the controller of FIG. It is a flowchart which shows the latter half part of the said diffraction ring reading program. It is a flowchart which shows the diffraction ring shape detection program performed by the controller of FIG. 6 is a flowchart showing a diffraction ring erasing program executed by the controller of FIG. 5. It is a flowchart which shows the stress calculation program performed by the controller of FIG. (A) is a top view in which an X-ray diffraction measurement device is arranged on the measurement object in the first diffraction ring measurement step, and (B) is an X-ray diffraction on the measurement object in the second diffraction ring measurement step. It is a top view which has arrange | positioned the measuring apparatus. It is a figure for demonstrating the relationship between the movement distance from the movement limit position of an imaging plate, and the radial direction distance (radius) of the irradiation position of the laser beam in an imaging plate. It is explanatory drawing explaining the locus | trajectory of a reading point. It is a graph which shows an example of the light reception curve for demonstrating the peak of signal strength.

An X-ray diffraction measurement apparatus according to an embodiment of the present invention will be described with reference to FIG. 1A is a front view of an X-ray diffraction measurement apparatus according to an embodiment of the present invention, FIG. 1B is a top view of the X-ray diffraction measurement apparatus, and FIG. 1C is the X-ray diffraction apparatus. It is a right view of a diffraction measuring apparatus.

This X-ray diffraction measurement apparatus has a case 10. The case 10 includes a flat front wall 11, a back wall 12, a top wall 13, a bottom wall 14, a left side wall 15, and a right side wall 16 and is formed in a rectangular parallelepiped shape from metal or resin. That is, the front wall 11 and the back wall 12 are parallel, and the front wall 11 and the back wall 12 are orthogonal to the top wall 13, the bottom wall 14, the left side wall 15, and the right side wall 16. The top wall 13 and the bottom wall 14 are also parallel, and the top wall 13 and the bottom wall 14 are orthogonal to the front wall 11, the back wall 12, the left side wall 15, and the right side wall 16. The left side wall 15 and the right side wall 16 are also parallel, and the left side wall 15 and the right side wall 16 are orthogonal to the front wall 11, the back wall 12, the top wall 13, and the bottom wall 14.

An inclined wall 17 is provided at the right end of the front wall 11 and the front end of the right side wall 16 so as to cut a corner portion sandwiched between the front wall 11 and the right side wall 16 relatively large. ing. The inclined wall 17 is a flat plate-like member that is inclined by 30 degrees from the extending direction to the right side at the right end portion of the front wall 11 toward the back wall 12, that is, the inner side of the case 10. That is, the inclined wall 17 intersects the front wall 11 at an angle of 150 degrees and intersects the right side wall 16 at an angle of 120 degrees. The inclined wall 17 intersects the top wall 13 and the bottom wall 14 at an angle of 90 degrees.

At the lower side end of the front wall 11 and the inclined wall 17 and the front side end of the bottom wall 14, a notch 18 is formed by notching a corner portion sandwiched between the front wall 11 and the bottom wall 14. ing. This notch 18 is also a flat member and intersects the front wall 11 and the bottom wall 14 at an angle of 135 degrees. The notch 18 is provided with an oval through-hole 18 a that penetrates the inside and the outside of the case 10 at a position near the inclined wall 17. A handle 19 is attached to the central portion of the top wall 13 so that a human can carry the X-ray diffraction measurement apparatus.

Next, the internal configuration of the X-ray diffraction measurement apparatus accommodated in the case 10 will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the X-ray diffraction measurement apparatus taken along line 2-2 in FIG. 1, and FIG. 3 is a cross-sectional view of the X-ray diffraction measurement apparatus taken along line 3-3 in FIG. is there. FIG. 4 is a cross-sectional view of the X-ray diffraction measurement apparatus taken along line 4-4 of FIG.

The X-ray diffraction measurement apparatus includes an X-ray emitter 20 that emits X-rays, a table 30 for mounting an imaging plate 31 on which a diffraction ring is formed by diffracted X-rays, and a table driving mechanism that rotates and moves the table 30. 40 and a laser detector 50 for measuring a diffraction ring formed on the imaging plate 31 are accommodated in the case 10.

The X-ray emitter 20 is formed in a long shape and extends in the left-right direction at a position near the corner where the back wall 12 and the top wall 13 in the case 10 intersect, and is fixed to the case 10 by a fixing member (not shown). It is fixed and emits X-rays upon receiving a high voltage supplied from a high voltage power supply 95 described later. This X-ray has a position in the vicinity of the intersection of the back wall 12 and the top wall 13 in a plane parallel to the right side wall 16 located slightly to the left of the left and right position where the front wall 11 and the inclined wall 17 intersect. The light is emitted in a direction that forms an angle of 45 degrees with respect to the front wall 11 and the bottom wall 14 from the upper position on the straight line that connects the rear position slightly with respect to the intersection position of the front wall 11 and the bottom wall 14. Is done. On the optical axis of the X-ray, a through hole 18a formed in the notch 18 described above is provided, and this X-ray is emitted from the inside of the case 10 to the outside through the through hole 18a. That is, when the case 10 is placed on the measurement object OB with the bottom wall 14 of the case 10 being in contact with the upper surface of the measurement object OB, the optical axis of the X-ray emitted from the X-ray emitter 20 is measured. The incident angle to the object OB (angle formed by the optical axis of the X-ray and the normal line of the measurement object OB) is 45 degrees. Further, the X-ray emitter 20 includes a cooling device (not shown).

When forming the diffraction ring by irradiating the measurement object OB with X-rays, as shown in FIG. 3, the front wall 11 is brought into contact with the vertical surface vp of the measurement object OB having an L-shaped cross section, When the case 10 is positioned so that the bottom wall 14 is in contact with the horizontal plane hp, the X-ray is in a position on the horizontal plane hp close to the vertical plane vp in a plane orthogonal to the vertical plane vp and the horizontal plane hp. Since it is necessary to irradiate, the optical axis of the X-ray emitted from the X-ray irradiator 20 is in a plane parallel to the right side wall 16 (that is, in a plane orthogonal to the front wall 11 and the bottom wall 14), and It is necessary to set the X-ray emission direction accurately so that the X-ray is irradiated to the position on the back wall 12 side slightly from the intersection line between the front wall 11 and the bottom wall 14.

The table driving mechanism 40 is fixed in the case 10 by a fixing member (not shown), and includes a moving stage 41 below the X-ray emitter 20. The moving stage 41 can be moved in a direction parallel to the front wall 11, the back wall 12, the top wall 13, and the bottom wall 14, that is, in a direction perpendicular to the left side wall 15 and the right side wall 16 by the feed motor 42 and the screw rod 43. It has become. The feed motor 42 is fixed in the table driving mechanism 40 and cannot move with respect to the case 10. The screw rod 43 extends in a direction perpendicular to the optical axis of the X-ray emitted from the X-ray emitter 20, and one end thereof is connected to the output shaft of the feed motor 42. The other end portion of the screw rod 43 is rotatably supported by a bearing portion 44 provided in the table drive mechanism 40. Further, the moving stage 41 is sandwiched between a pair of opposed plate-

like guides

45, 45 fixed in the table driving mechanism 40, respectively, and can move along the axial direction of the screw rod 43. ing. That is, when the feed motor 42 is driven forward or backward, the rotational motion of the feed motor 42 is converted into the linear motion of the moving stage 41. An encoder 42 a is incorporated in the feed motor 42. The encoder 42a outputs a pulse train signal that alternately switches between a high level and a low level each time the feed motor 42 rotates by a predetermined minute rotation angle.

The upper ends of the pair of guides 45 are connected by a plate-like upper wall 46. A through hole 46 a is provided in the upper wall 46, and the distal end portion of the emission port 21 of the X-ray emitter 20 is inserted into the through hole 46 a. The positions of the X-ray emitter 20 and the moving stage 41 are set so that the tip of the emission port 21 of the X-ray emitter 20 does not contact the moving stage 41.

Also, a spindle motor 47 is assembled to the moving stage 41. In the spindle motor 47, an encoder 47a similar to the encoder 42a is incorporated. That is, the encoder 47a outputs a pulse train signal that alternately switches between a high level and a low level each time the spindle motor 47 rotates by a predetermined minute rotation angle. Furthermore, the encoder 47a outputs an index signal that switches from a low level to a high level for a predetermined short period of time each time the spindle motor 47 rotates once.

The table 30 is formed in a circular shape and is fixed to the tip of the output shaft of the spindle motor 47. The center axis of the table 30 coincides with the center axis of the output shaft of the spindle motor 47. The table 30 has a protruding portion 32 that protrudes downward from the central portion of the lower surface, and a thread is formed on the outer peripheral surface of the protruding portion 32. The central axis of the protruding portion 32 coincides with the central axis of the output shaft of the spindle motor 47. An imaging plate 31 is attached to the lower surface of the table 30. The imaging plate 31 is a circular plastic film whose surface is coated with a phosphor. A through hole 31a is provided in the center of the imaging plate 31, and the imaging plate 31 is fixed by screwing a nut-shaped fixture 33 into the protruding part 32 by passing the protruding part 32 through the through hole 31a. It is sandwiched and fixed between the tool 33 and the table 30. The fixture 33 is a cylindrical member, and a thread corresponding to the thread of the protrusion 32 is formed on the inner peripheral surface.

The imaging plate 31 is driven by the feed motor 42 and moves together with the moving stage 41, the spindle motor 47 and the table 30 from the origin position to the diffraction ring imaging position for imaging the diffraction ring. The imaging plate 31 is driven by the feed motor 42 while being rotated by the spindle motor 47, and is driven by the feed motor 42 to read the imaged diffraction ring together with the moving stage 41, the spindle motor 47 and the table 30, and in the diffraction ring reading region. It moves in the diffractive ring erasing region that erases the diffractive ring. In the movement of the imaging plate 31 in this case, the front wall 11, the back wall 12, the top wall 13, and the center axis of the imaging plate 31 include the optical axis of the X-ray emitted from the X-ray emitter 20. It moves in a direction orthogonal to the optical axis of the X-ray while being maintained in a plane orthogonal to the bottom wall 14, that is, in a plane parallel to the left side wall 15 and the right side wall 16.

Further, the moving stage 41, the output shaft of the spindle motor 47, the table 30, the imaging plate 31, and the fixture 33 are provided with through holes through which the X-rays emitted from the X-ray emitter 20 pass. The center axis of these through holes and the rotation axis of the table 30 are coincident. That is, when the central axis of these through holes and the optical axis of the X-ray emitted from the X-ray emitter 20 coincide, the X-ray is irradiated onto the measurement object OB. Thus, the position of the imaging plate 31 when irradiating the measurement object OB with X-rays is the diffraction ring imaging position.

Below the feed motor 42, a light receiving sensor 35 (for example, an X-ray CCD) for detecting the distance between the measurement object OB and the imaging plate 31 is assembled by a fixing member (not shown). The light receiving sensor 35 includes a plurality of light receiving elements that receive X-rays reflected by the measurement object OB, and is sufficiently separated from the measurement object OB and the imaging plate 31 toward the feed motor 42 side. Thus, when the imaging plate 31 is at the diffraction ring imaging position, the light receiving sensor 35 can directly receive the X-ray reflected by the measurement object OB. The light receiving position of the X-ray on the light receiving surface of the light receiving sensor 35 corresponds to the height of the measurement object OB. In other words, this corresponds to the distance between the imaging plate 31 and the measurement object OB. The light receiving sensor 35 outputs a light receiving signal received by each light receiving element.

The laser detection device 50 detects the intensity of light incident from the imaging plate 31 by irradiating the imaging plate 31 that images the diffraction ring with laser light. The laser detector 50 is sufficiently separated from the through hole 18 a provided in the notch 18 and the imaging plate 31 at the diffraction ring imaging position toward the feed motor 42. That is, when the imaging plate 31 is at the diffraction ring imaging position, the X-ray diffracted by the measurement object OB is not blocked by the laser detection device 50.

Next, the laser detector 50 will be described. The laser detection device 50 includes a laser light source 51, a collimating lens 52, a reflecting mirror 53, a polarizing beam splitter 54, a quarter wavelength plate 55, and an objective lens 56, as indicated by broken lines in FIG. The laser light source 51 emits laser light that irradiates the imaging plate 31. The collimating lens 52 converts the laser light emitted from the laser light source 51 into parallel light. The reflecting mirror 53 reflects the laser light converted into parallel light by the collimating lens 52 toward the polarizing beam splitter 54. The polarization beam splitter 54 transmits most of the laser light incident from the reflecting mirror 53 (for example, 95%) as it is and guides it to the quarter-wave plate 55. The quarter wave plate 55 converts the laser light incident from the polarization beam splitter 54 from linearly polarized light to circularly polarized light. The objective lens 56 focuses the laser light incident from the quarter wavelength plate 55 on the surface of the imaging plate 31. The optical axis of the laser light emitted from the objective lens 56 is a plane orthogonal to the front wall 11, the back wall 12, the top wall 13, and the bottom wall 14 including the optical axis of the X-ray emitted from the X-ray emitter 20. It is in a plane parallel to the inner side, that is, the left side wall 15 and the right side wall 16 and is parallel to the optical axis of the X-ray, that is, a direction perpendicular to the moving direction of the moving stage 41.

A focus actuator 57 is assembled to the objective lens 56. The focus actuator 57 is an actuator that moves the objective lens 56 in the optical axis direction of the laser light. The objective lens 56 is located at the center of the movable range when the focus actuator 57 is not energized.

When the laser beam condensed by the objective lens 56 is irradiated onto the surface of the imaging plate 31 where the diffraction ring is imaged, a photo-stimulated luminescence phenomenon occurs. That is, after imaging the diffraction ring, when the imaging plate 31 is irradiated with laser light, the phosphor of the imaging plate 31 is light corresponding to the intensity of the diffracted X-ray, and light having a wavelength shorter than the wavelength of the laser light. To emit. The reflected light of the laser beam irradiated and reflected on the imaging plate 31 and the light emitted from the phosphor pass through the objective lens 56 and the quarter wavelength plate 55 and are reflected by the polarization beam splitter 54. In the reflection direction of the polarization beam splitter 54, a condensing lens 58, a cylindrical lens 59, and a photodetector 60 are provided. The condensing lens 58 condenses the light incident from the polarization beam splitter 54 on the cylindrical lens 59. The cylindrical lens 59 causes astigmatism in the transmitted light. The photodetector 60 is constituted by a four-divided light receiving element composed of four light receiving elements of the same square shape divided by dividing lines, and the light incident on the light receiving areas A, B, C, and D arranged in the clockwise direction. A detection signal having a magnitude proportional to the intensity is output as a light reception signal (a, b, c, d).

Further, the laser detection device 50 includes a condenser lens 61 and a photodetector 62. The condensing lens 61 condenses the laser light that is a part of the laser light emitted from the laser light source 51 and reflected without passing through the polarization beam splitter 54 on the light receiving surface of the photodetector 62. The photodetector 62 is a light receiving element that outputs a light reception signal corresponding to the intensity of light collected on the light receiving surface. Therefore, the photodetector 62 outputs a light reception signal corresponding to the intensity of the laser light emitted from the laser light source 51.

Also, an LED 63 is provided adjacent to the objective lens 56. The LED 63 emits visible light and erases the diffraction ring imaged on the imaging plate 31.

The case 10 also includes an electric control device 70 that is connected to the X-ray emitter 20, the table drive mechanism 40, and the laser detection device 50 to control the operation thereof and to input detection signals. ing. The electric control device 70 will be described with reference to FIG. The electric control device 70 surrounded by a two-dot chain line in FIG. 5 is housed in the case 10 as indicated by a two-dot chain line in FIGS. However, in FIG.2 and FIG.4, the connection line of the electric control apparatus 70, the X-ray emitter 20, the table drive mechanism 40, and the laser detection apparatus 50 is abbreviate | omitted. In FIG. 5, the case 10 is omitted.

The electric control device 70 includes a circuit described below. The X-ray control circuit 71 is controlled by a controller 91 that configures a computer device 90 to be described later, and a driving current supplied to the X-ray emitter 20 so that X-rays with a certain intensity are emitted from the X-ray emitter 20. And control the drive voltage. The X-ray control circuit 71 also controls a drive signal supplied to the cooling device built in the X-ray emitter 20. Thereby, the temperature of the X-ray emitter 20 is kept constant. The X-ray emitter 20 is supplied with a high voltage from a high voltage power supply 95, but the high voltage power supply 95 is not included in the electric control device 70.

A position detection circuit 72 and a feed motor control circuit 73 are connected to the encoder 42a in the feed motor 42, and a feed motor control circuit 73 is connected to the feed motor 42. The position detection circuit 72 and the feed motor control circuit 73 start to operate in response to a command from the controller 91. Immediately after the start of measurement, the feed motor control circuit 73 drives the feed motor 42 to move the moving stage 41 to the feed motor 42 side. When the pulse signal output from the encoder 42a is not input, the position detection circuit 72 outputs a signal indicating that the movement stage 41 has reached the movement limit position to the feed motor control circuit 73, and sets the count value to “0”. Set to. When the feed motor control circuit 73 receives a signal indicating that the movement limit position has been reached from the position detection circuit 72, the feed motor control circuit 73 stops outputting the drive signal to the feed motor 42. The above movement limit position is set as the origin position of the moving stage 41. Therefore, the position detection circuit 72 outputs a position signal representing “0” when the moving stage 41 moves to the left in FIG. 5 and reaches the movement limit position, and the movement stage 41 moves to the right from the movement limit position. When moving to, a signal representing the movement distance x from the movement limit position is output as a position signal.

When the feed motor control circuit 73 receives a set value indicating the position of the moving stage 41 from the controller 91, the feed motor control circuit 73 drives the feed motor 42 in the forward or reverse direction according to the set value. The position detection circuit 72 counts the number of pulses of the pulse signal output from the encoder 42a. Then, the position detection circuit 72 calculates the current position of the movement stage 41 (movement distance x from the movement limit position) using the counted number of pulses, and outputs it to the controller 91 and the feed motor control circuit 73. The feed motor control circuit 73 drives the feed motor 42 until the current position of the moving stage 41 input from the position detection circuit 72 matches the position of the moving destination input from the controller 91.

Further, the feed motor control circuit 73 inputs a set value indicating the moving speed of the moving stage 41 from the controller 91. Then, the moving speed of the moving stage 41 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 42a, so that the calculated moving speed of the moving stage 41 becomes the moving speed input from the controller 91. The feed motor 42 is driven.

A spindle motor control circuit 74 and a rotation angle detection circuit 75 are connected to the encoder 47a in the spindle motor 47, and a spindle motor control circuit 74 is connected to the spindle motor 47. The spindle motor control circuit 74 and the rotation angle detection circuit 75 start to operate in response to a command from the controller 91. The spindle motor control circuit 74 inputs a setting value representing the rotational speed of the spindle motor 47 from the controller 91. Then, the rotational speed of the spindle motor 47 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 47a, and the drive signal is input to the spindle so that the calculated rotational speed becomes the rotational speed input from the controller 91. The motor 47 is supplied. The rotation angle detection circuit 75 counts the number of pulses of the pulse train signal output from the encoder 47a, calculates the rotation angle of the spindle motor 47, that is, the rotation angle θp of the imaging plate 31 using the count value, and sends it to the controller 91. Output. Then, when the rotation angle detection circuit 75 receives the index signal output from the encoder 47a, the rotation angle detection circuit 75 sets the count value to “0”. That is, the position where the index signal is input is the reference position with a rotation angle of 0 degree.

A sensor signal extraction circuit 76 is connected to the light receiving sensor 35. The sensor signal extraction circuit 76 starts to operate in response to a command from the controller 91, detects the peak position of the light receiving signal on the light receiving surface of the light receiving sensor 35 using the light receiving signal input from the light receiving sensor 35, and corresponds to the peak position. A light receiving position signal representing the received light receiving position is output to the controller 91.

A laser drive circuit 77 is connected to the laser light source 51 and the photodetector 62. The laser drive circuit 77 is controlled by the controller 91, receives the light reception signal output from the photodetector 62, and controls the drive signal output to the laser light source 51 so that the intensity of the light reception signal becomes a predetermined intensity. Thereby, the intensity of the laser light applied to the imaging plate 31 is kept constant.

The LED drive circuit 84 is connected to the LED 63. The LED drive circuit 84 is controlled by the controller 91 and supplies a drive signal for generating visible light having a predetermined intensity to the LED 63.

An amplifying circuit 78 is connected to the photodetector 60. The amplification circuit 78 amplifies the light reception signals (a, b, c, d) output from the photodetector 60 with the same amplification factor to generate light reception signals (a ′, b ′, c ′, d ′), Output to the focus error signal generation circuit 79 and the SUM signal generation circuit 80. In this embodiment, focus servo control based on the astigmatism method is used. The focus error signal generation circuit 79 generates a focus error signal by calculation using the amplified light reception signals (a ′, b ′, c ′, d ′). That is, the focus error signal generation circuit 79 calculates (a ′ + c ′) − (b ′ + d ′) and outputs the calculation result to the focus servo circuit 81 as a focus error signal. The focus error signal (a ′ + c ′) − (b ′ + d ′) represents the amount of deviation of the focal position of the laser beam from the surface of the imaging plate 31.

The focus servo circuit 81 is controlled by the controller 91, generates a focus servo signal based on the focus error signal, and outputs the focus servo signal to the drive circuit 82. The drive circuit 82 drives the focus actuator 57 according to the focus servo signal to displace the objective lens 56 in the optical axis direction of the laser light. In this case, the focus servo signal is generated so that the value of the focus error signal (a ′ + c ′) − (b ′ + d ′) is always a constant value (for example, zero), so that the laser is applied to the surface of the imaging plate 31. The light can be continuously collected.

The SUM signal generation circuit 80 adds the received light signals (a ′, b ′, c ′, d ′) to generate a SUM signal (a ′ + b ′ + c ′ + d ′) and outputs it to the A / D conversion circuit 83. To do. The intensity of the SUM signal corresponds to the intensity of the laser beam reflected by the imaging plate 31 and the intensity of the light generated by the stimulated emission, but the intensity of the laser beam reflected by the imaging plate 31 is substantially constant. Therefore, the intensity of the SUM signal corresponds to the intensity of light generated by the stimulated light emission. That is, the intensity of the SUM signal corresponds to the intensity of the diffracted X-ray incident on the imaging plate 31. The A / D conversion circuit 83 is controlled by the controller 91, receives the SUM signal from the SUM signal generation circuit 80, converts the instantaneous value of the input SUM signal into digital data, and outputs the digital data to the controller 91.

The computer device 90 includes a controller 91, an input device 92, and a display device 93. The controller 91 is an electronic control unit mainly including a microcomputer including a CPU, a ROM, a RAM, a mass storage device, and the like, and executes various programs shown in FIGS. 6 to 10 stored in the mass storage device. . The input device 92 is connected to the controller 91 and is used by the measurer to input various parameters, work instructions, and the like. The display device 93 visually informs the measurer of various setting conditions, operating conditions, measurement results, and the like. The high voltage power source 95 supplies a high voltage for X-ray emission to the X-ray emitter 20. In the present embodiment, the case 10 and various devices incorporated in the case 10 are referred to as an X-ray diffraction measurement device, and a computer device 90 and a high-voltage power supply 95 added to the X-ray diffraction measurement device X This is called a line diffraction measurement system.

Next, a procedure for measuring the residual stress of the measurement object OB using this X-ray diffraction measurement system will be described. The measurement object OB is formed in an L shape with a cross section having an angle of 90 degrees, as indicated by a two-dot chain line in FIG. 3 and a solid line in FIG. The measurement object OB has a horizontal plane hp and a vertical plane vp that form an angle of 90 degrees. This type of measuring object OB is an iron part or iron member having an L-shaped cross section in which two iron metal plates are intersected at an angle of 90 degrees and the intersecting portion is joined by welding. However, the present invention is not limited to the case where two metal plates are joined by welding, but an iron part or an iron member formed into a L-shaped cross section having a 90-degree cross section by a die, a bending process, or the like. Also applies. Here, the residual stress to be measured is the residual stress in the vicinity of the corner of the horizontal plane hp, which is perpendicular to the vertical plane vp, that is, perpendicular to the extending direction of the corner and parallel to the horizontal plane hp. The residual stress in the direction (hereinafter referred to as the X direction) and the residual stress in the direction parallel to the vertical plane vp and the horizontal plane hp, that is, the direction parallel to the extending direction of the corner (hereinafter referred to as the Y direction). Hereinafter, the residual stress in the X direction in this plane stress state is σx, and the residual stress in the Y direction is σy. Moreover, let τxy be the residual stress of shear in this plane stress state.

In order to measure the residual stress σx in the X direction and the residual stress σy in the Y direction, it is necessary to measure the first and second diffraction rings by the first and second diffraction ring measurement steps, respectively. In the first diffraction ring measurement step, as shown in FIG. 11A, the bottom wall 14 is brought into contact with the horizontal plane hp of the measurement object OB and the case 10 is placed on the horizontal plane hp, and the front wall 11 is brought into contact with the vertical plane vp. Thereby, in this case, the X-ray has an angle of 45 degrees with respect to the horizontal plane hp, that is, an incident angle 45 in a plane orthogonal to the horizontal plane hp and the vertical plane vp, as indicated by a one-dot chain arrow in the figure. The horizontal plane hp is irradiated from the X direction at a degree. Further, in the second diffraction ring measurement step, as shown in FIG. 11B, the bottom wall 14 is brought into contact with the horizontal plane hp of the measurement object OB and the case 10 is placed on the horizontal plane hp, The inclined wall 17 is brought into contact with the vertical surface vp. Thereby, in this case, the X-ray is 45 degrees with respect to the horizontal plane hp within a plane perpendicular to the horizontal plane hp and 60 degrees with respect to the vertical plane vp, as indicated by a dashed line arrow in the figure. The horizontal plane hp is irradiated from a direction at an angle of 45 degrees with respect to the horizontal plane hp in a plane parallel to a direction that forms an angle of 30 degrees with the X direction on the horizontal plane hp and perpendicular to the horizontal plane hp.

In the first and second diffraction ring measurement steps, a diffraction ring imaging step for forming a diffraction ring on the imaging plate 31, a diffraction ring reading step for reading the diffraction ring formed on the imaging plate 31, A diffraction ring shape detecting step for detecting the shape and a diffraction ring erasing step for erasing the diffraction ring formed on the imaging plate 31 are performed. In the stress calculation process, residual stresses σx and σy in the X direction and the Y direction are calculated using the shapes of the two diffraction rings detected in the first and second diffraction ring measurement processes.

Hereinafter, the first and second diffraction ring measurement steps and the stress calculation step including the diffraction ring imaging step, the diffraction ring reading step, the diffraction ring shape detection step, and the diffraction ring elimination step will be described in detail.

First, the first diffraction ring measurement step will be described. The measurer carries the diffraction ring measurement device with the handle 19 and moves the bottom wall 14 of the measurement object OB as shown in FIG. The case 10 is placed on the horizontal plane hp in contact with the horizontal plane hp, and the front wall 11 is in contact with the vertical plane vp. Then, the high voltage power supply 95 is connected to the X-ray emitter 20 and the computer device 90 is connected to the electric control device 70. Then, the measurer inputs the material (for example, iron) of the measurement object OB using the input device 92 and instructs the start of measurement of the residual stress. Thereby, the controller 91 starts execution of the diffraction ring imaging program shown in FIG.

The diffraction ring imaging program is started in step S100 of FIG. 6, and the controller 91 controls the spindle motor control circuit 74 to rotate the imaging plate 31 at a low speed and inputs an index signal from the encoder 47a in step S102. At that time, the rotation of the imaging plate 31 is stopped. Thereby, at the start of measurement, the rotation angle of the imaging plate 31 is set to 0 degree. Next, the controller 91 starts the operation of the position detection circuit 72 in step S104, controls the feed motor control circuit 73 in step S106, and starts the operation of the feed motor 42. Thus, the operation of the feed motor 42 is stopped, and the imaging plate 31 is moved to the diffraction ring imaging position.

Next, the controller 91 starts the operation of the sensor signal extraction circuit 76 in step S108. Next, in step S110, the controller 91 controls the X-ray control circuit 71 to cause the X-ray emitter 20 to start emitting X-rays. Thereby, X-rays are irradiated onto the measurement object OB, and the X-rays reflected on the surface of the measurement object OB are received by the light receiving sensor 35. Next, in step S112, the controller 91 inputs a light reception position signal from the sensor signal extraction circuit 76, and calculates the distance L between the imaging plate 31 and the measurement object OB using the input light reception position signal. Note that the calculated distance L is stored in a memory because it is used by processing to be described later. In step S114, the controller 91 determines whether or not the calculated distance L is within a predetermined reference range. If the distance L is not within the reference range, it is determined as “No”, and in step S116, the X-ray control circuit 71 is controlled to stop the irradiation of the measurement object OB with X-rays.

Then, in step S118, the controller 91 displays on the display device 93 that the set of the X-ray diffraction measurement device is inappropriate. In step S128, the execution of the diffraction ring imaging program ends. In this case, the measurer resets the X-ray diffraction measurement device again, and then instructs the start of measurement again using the input device 92. Since the time required from the above steps S110 to S116 is very short, the diffractive ring is not imaged on the imaging plate 31. Even when the light receiving sensor 35 does not receive the X-ray reflected by the measurement object OB, a message that the set of the X-ray diffraction measurement device is inappropriate is displayed in step S118. Also in this case, the measurer resets the X-ray diffraction measurement apparatus. Then, in response to the measurement start instruction, the processes of steps S102 to S114 described above are executed again, and the processes are repeated until the distance L is within a predetermined reference range. However, when the processes of steps S102 to S114 are repeatedly executed as described above, the processes of steps S102 to S108 are substantially unnecessary.

On the other hand, when the distance L is within the predetermined reference range at the time of the determination process in step S114, the controller 91 determines “Yes” in step S114, proceeds to step S120, and outputs a sensor signal extraction circuit. The operation of 76 is stopped. The controller 91 starts time measurement in step S122, and determines in step S124 whether or not a predetermined set time for forming a diffraction ring by X-rays on the imaging plate 31 has elapsed. If the predetermined set time has not elapsed since the start of time measurement, it is determined as “No” in step S124, and the determination process is continued. That is, the controller 91 stands by until a predetermined set time elapses from the start of time measurement. Then, when a predetermined set time has elapsed from the start of time measurement, the controller 91 determines “Yes” in step S124, and controls the X-ray control circuit 71 in step S126 to control the X-ray emitted by the X-ray emitter 20. The irradiation of the line is stopped, and the execution of the diffraction ring imaging program is terminated in step S128.

Thereby, in this state, a diffraction ring by diffraction X-rays from the measurement object OB is imaged on the imaging plate 31. In this case, a diffraction ring is formed on the imaging plate 31 by the X-rays irradiated to the horizontal plane hp from the X direction at an incident angle of 45 degrees in a plane orthogonal to the horizontal plane hp and the vertical plane vp.

After execution of the diffraction ring imaging program, the controller 91 starts execution of the diffraction ring reading program of FIGS. 7A and 7B. In this case, the controller 91 also starts executing the diffraction ring shape detection program of FIG. 8 in parallel with the execution of the diffraction ring reading program. The execution of the diffraction ring reading program is started in step S200 of FIG. 7A, and the controller 91 calculates the diffraction ring reference radius R0 in step S202. The diffraction ring reference radius R0 is the radius of the diffraction ring when the residual stress of the measurement object OB is “0”. The diffraction ring reference radius R0 depends on the material of the measurement object OB and the distance L from the imaging plate 31 to the measurement object OB. That is, since the residual stress is “0”, the diffraction angle θx is determined by the material (in this embodiment, iron). Since the distance L and the diffraction ring reference radius R0 are in a proportional relationship, if the diffraction angle θx is stored in advance for each material, the diffraction ring reference radius R0 is calculated by the calculation of R0 = L · tan (θx). it can. The calculated diffraction ring reference radius R0 is stored in the memory.

After the processing in step S202, the controller 91 instructs the feed motor control circuit 73 to move the imaging plate 31 to the reading start position in the diffraction ring reading region in step S204. The feed motor control circuit 73 drives and controls the feed motor 42 in cooperation with the position detection circuit 72 to move the imaging plate 31 to the reading start position. When the imaging plate 31 is in the reading start position, the center of the objective lens 56, that is, the irradiation position of the laser beam is located at a position smaller than the calculated diffraction ring reference radius R0 by a predetermined distance α. The predetermined distance α is a distance that is slightly larger than the distance at which the radius of the imaged diffraction ring may deviate from the diffraction ring reference radius R0. Thereby, the measurement of the diffraction ring is started sufficiently from the inside of the diffraction ring by the processing described later, and the diffraction ring is reliably detected.

Here, the position signal from the position detection circuit 72 indicating the movement distance x from the movement limit position of the moving stage 41 to the right in FIG. 5 and the irradiation position of the laser beam from the center of the imaging plate 31 (center of the objective lens 56). The relationship with the distance to the position (that is, the radius r of the irradiation position of the laser beam) will be described. In the state where the moving stage 41, that is, the imaging plate 31 is at the movement limit position, the distance from the center of the imaging plate 31 to the center position of the objective lens 56 is Rx, as shown in FIG. In this case, the objective lens 56 is leftward in FIG. 5 from the center position of the imaging plate 31, and the distance Rx is measured in advance and stored in the controller 91. On the other hand, as shown in FIG. 12B, when the imaging plate 31 is moved from the movement limit position to the right in FIG. 5 by the distance x, the radius r of the irradiation position of the laser beam is represented by r = x + Rx. . In this case, since the distance x is indicated by the position signal output from the position detection circuit 72 as described above, the radius r of the irradiation position of the laser beam is the position output from the position detection circuit 72 in future processing. The value Rx stored in advance is added to the distance x represented by the signal.

As described above, when the imaging plate 31 is moved to the reading start position, as shown in FIG. 12C, the irradiation position of the laser beam is on the inner side by a predetermined distance α from the diffraction ring reference radius R0. The radius r in this case should be equal to the distance R0-α. Therefore, the distance x for moving the imaging plate 31 from the drive limit position to the right in FIG. 5 is equal to x = R0−α−Rx. That is, in the movement process to the reading start position in step S204, the table 30 is moved to the right in FIG. 5 by the distance x (= R0−α−Rx) represented by the position signal output from the position detection circuit 72. Just move to.

Next, in step S206, the controller 91 instructs the spindle motor control circuit 74 to rotate the imaging plate 31 at a predetermined constant rotational speed. The spindle motor control circuit 74 controls the rotation of the spindle motor 47 so that the imaging plate 31 rotates at the specified constant rotation speed while calculating the rotation speed using the pulse signal from the encoder 47a. Therefore, the imaging plate 31 starts to rotate at the predetermined constant rotation speed. Next, in step S208, the controller 91 controls the laser driving circuit 77 to start irradiation of the imaging plate 31 with laser light from the laser light source 51.

Next, in step S210, the controller 91 instructs the focus servo circuit 81 to start focus servo control. Accordingly, the focus servo circuit 81 starts focus servo control by driving and controlling the focus actuator 57 via the drive circuit 82 using the focus error signal from the amplifier circuit 78 and the focus error signal generation circuit 79. . As a result, the objective lens 56 is driven and controlled in the optical axis direction so that the focus of the laser light is on the surface of the imaging plate 31. After the process of step S210, the controller 91 starts the operation of the rotation angle detection circuit 75 and the A / D conversion circuit 83 in step S212. As a result, the rotation angle detection circuit 75 starts outputting the rotation angle θp from the reference position of the spindle motor 47 (imaging plate 31) to the controller 91, and the A / D conversion circuit 83 digital data of the instantaneous value of the SUM signal. Starts to be output to the controller 91.

Next, the controller 91 instructs the feed motor control circuit 73 to start and move the imaging plate 31 in step S214. The feed motor control circuit 73 drives and controls the feed motor 42 to move the imaging plate 31 from the reading start position to the bearing portion 44 side (right direction in FIG. 5) at a constant speed. Thereby, the irradiation position of the laser light starts to move relative to the imaging plate 31 at a constant speed from the inside to the outside by a predetermined distance α from the diffraction ring reference radius R0. In this state, the irradiation position of the laser beam is relatively spirally rotated on the imaging plate 31 by the processing in steps S206 and S214.

After the process of step S214, the controller 91 initially sets the values of the circumferential direction number n and the radial direction number m to “1” in step S216. The circumferential direction number n is an integer that changes from “1” to the maximum value N, each representing a circumferential position obtained by equally dividing N rotations (predetermined large values) in one rotation of the imaging plate 31. The radial direction number m represents a radial position from the inside toward the outside of the imaging plate 31 and is a value that increases by “1” from “1” every time the imaging plate 31 rotates once. The circumferential direction number n and the radial direction number m indicate a reading point P (n, m) that moves spirally on the imaging plate 31 as shown in FIG.

Next, in step S218, the controller 91 determines whether or not the rotation angle detection circuit 75 has input an index signal from the encoder 47a. If the rotation angle detection circuit 75 has not input the index signal, the controller 91 determines “No” in step S218 and continues to execute the determination process in step S218 repeatedly. When the rotation angle detection circuit 75 inputs the index signal, the controller 91 determines “Yes” in step S218, and takes in the current rotation angle θp of the imaging plate 31 from the rotation angle detection circuit 75 in step S220. .

In step S222, the controller 91 calculates the difference between the current rotation angle θp and the rotation angle (n−1) · θo specified by the variable n (in this case, n = 1 and “0”). It is determined whether or not the absolute value | θp− (n−1) · θo | is less than a predetermined allowable value. In this case, θo is a predetermined value stored in advance by dividing 360 degrees by the maximum value N of the circumferential direction number n. If the absolute value | θp− (n−1) · θo | is not less than the predetermined allowable value, the controller 91 makes a “No” determination in step S222 to repeatedly execute the processes in steps S220 and S222. That is, the controller 91 stands by until the current rotation angle θp substantially matches the predetermined rotation angle (n−1) · θo. When the current rotation angle θp substantially coincides with the predetermined rotation angle (n−1) · θo, the controller 91 determines “Yes”, that is, the absolute value | θp− (n−1) · θo | Is less than the predetermined allowable value, the process proceeds to step S224.

In step S224, the controller 91 takes the SUM signal from the A / D conversion circuit 83 and stores it in the memory as the signal intensity S (n, m) of the reading point P (n, m). Further, in this step S224, the position signal from the position detection circuit 72 is taken, the radius r is calculated by adding the predetermined distance Rx to the distance x represented by the position signal, and the reading point P (n, m ) Radius r (n, m) and stored in the memory in correspondence with the signal intensity S (n, m). Thereby, the signal intensity S (n, m) representing the intensity of the stimulated emission from the reading point P (n, m) of the imaging plate 31, that is, the intensity of the X-ray diffracted light with respect to the reading point P (n, m), It is stored in memory with a radius r (n, m) representing the radius of the read point P (n, m).

Next, in step S226, the controller 91 determines whether or not the stored signal intensity S (n, m) is equal to or greater than a predetermined reference value. If the signal intensity S (n, m) is greater than or equal to the predetermined reference value, the controller 91 determines “Yes” in step S226 and proceeds to step S230. On the other hand, if the signal strength S (n, m) is smaller than the predetermined reference value, the controller 91 determines “No” in step S226, and in step S228, the stored signal strength S (n, m). After erasing m) and radius r (n, m), the process proceeds to step S230. The signal intensity S (n, m) and the radius r (n, m) are erased when the signal intensity S (n, m) smaller than a predetermined reference value is detected as the peak position of the diffraction X-ray intensity in the radial direction of the diffraction ring. This is because it is unnecessary.

In step S230, the controller 91 adds “1” to the circumferential direction number n. In step S232, the controller 91 determines whether the variable n is larger than a value N representing the number of reading points P (n, m) per round, that is, whether the imaging plate 31 has made one rotation. . In this case, since n = 2 and the circumferential direction number n is equal to or less than the value N, the controller 91 determines “No” in step S232 and returns to step S220.

Then, the processes in steps S220 to S232 described above are repeated until the circumferential direction number n becomes larger than the value N. By repeating the steps S220 to S232, the signal intensity S (n, m) and radius r () for each predetermined angle θo corresponding to the rotation angles 0, θo, 2 · θo (N−1) · θo, respectively. n, m) is stored in the memory. However, also in this case, if the signal strength S (n, m) is smaller than a predetermined reference value by the processing in steps S226 and S228, the signal strength S (n, m) and the radius r (n, m) stored in the memory are stored. m) is erased.

When the circumferential direction number n becomes larger than the value N by the circulation process in steps S220 to S232, the controller 91 determines “Yes” in step S232, and in step S234, the diffractive ring shape to be described later. The presence or absence of an end command by the detection program is determined. If there is no end command yet, the controller 91 determines “No” in step S234, adds “1” to the radial direction number m in step S236 (in this case, m = 2), and step In S228, the circumferential direction number n is returned to "1". Then, the controller 91 executes the processing of steps S218 to S232 described above to read the reading point P corresponding to the rotation angles 0, θo, 2 · θo (N−1) · θo at the next radial position. The signal strength S (n, m) and radius r (n, m) for (n, m) are stored in the memory.

Then, until the end command is given, the processing in steps S218 to S238 is performed to increase the radial direction number m (= 1, 2, 3,...) Sequentially increasing by “1” and each radial direction number m. Corresponding to the reading point P (n, m) specified by the circumferential direction number n (= 1 to N) corresponding to the rotation angles 0, θo, 2 · θo (N-1) · θo, respectively. The signal strength S (n, m) and the radius r (n, m) are sequentially stored in the memory. Also in this case, if the signal strength S (n, m) is smaller than a predetermined reference value, the signal strength S (n, m) and the radius r (n, m) stored in the memory are deleted.

Then, when there is an instruction to end the diffraction ring shape detection program, the controller 91 determines “Yes” in step S234 and proceeds to step S240 in FIG. 7B. Here, a diffraction ring shape detection program executed in parallel with the diffraction ring reading program will be described.

Execution of the diffraction ring shape detection program is started in step S300 of FIG. 8, and the controller 91 initially sets the circumferential direction number n to “1” in step S302. The circumferential direction number n indicates the circumferential position for each predetermined angle θo as in the case of the diffraction ring reading program, but is independent of the circumferential direction number n used in the diffraction ring reading program. is there.

After the process of step S302, the controller 91 determines in step S304 whether a peak radius rp (n) described later in detail exists, that is, whether the peak radius rp (n) has been detected. In this case, at the peak radius rp (n), the rotation angle of the detected peak radius is represented by the circumferential direction number n. If the peak radius rp (n) has already been detected, the controller 91 determines “Yes” in step S304, adds “1” to the circumferential direction number n in step S306, and then proceeds to step S308. It is determined whether or not the direction number n is greater than a predetermined number. The predetermined number in this case is also a value N representing the number of measurement positions in one round. If the circumferential direction number n is less than or equal to the predetermined number, the controller 91 determines “No” in step S308 and returns to step S304.

On the other hand, if the peak radius rp (n) is not detected, the controller 91 determines “No” in step S304, and stores the signal intensity S (() stored in step S310 by the process of step S224 in FIG. 7A. It is determined whether the number of (n, m) is greater than or equal to a predetermined number. If the number of the signal strengths S (n, m) is not equal to or greater than the predetermined number, the controller 91 determines “No” in step S310 and executes the processes of steps S306 and S308 described above to execute step S304 or step S304. Return to S302. This is because the determination processing in step S310 is useless even if the peak detection processing described later is executed when the number of signal strengths S (n, m) is small. Note that the signal strength S (n, m) erased by the process of step S228 in FIG. 7 is not counted as the stored signal strength S (n, m).

On the other hand, when the number of the stored signal strengths S (n, m) is equal to or larger than the predetermined number, the controller 91 determines “Yes” in step S310 and determines the presence or absence of a peak in step S312. To do. That is, the presence / absence of a peak in the value of the SUM signal is determined using all the radii r (n, m) and the signal strength S (n, m) at the circumferential position designated by the circumferential number n. Specifically, as shown in FIG. 14, all the radii r (n, m) at the circumferential position designated by the circumferential direction number n are taken on the horizontal axis and corresponded to the radius r (n, m). Whether the signal intensity S (n, m) has a peak in the light receiving curve with the signal intensity S (n, m) on the vertical axis, that is, has the signal intensity S (n, m) decreased after increasing? It is good to judge. If there is no peak, the controller 91 determines “No” in step S312, performs the processes of steps S306 and S308 described above, and returns to step S304 or step S302.

As described above, while the steps S302 to S312 are repeatedly executed, the radius r (n, m) and the signal intensity S (n, m) are further increased by the processing of the diffraction ring reading program executed in parallel. It is taken in and stored in memory one after another. Therefore, the peak is detected in step S312, and when detected, the controller 91 determines “Yes” in step S312, and in step S314, the peak radius r (n, m). ) As a peak radius rp (n). Next, in step S316, the controller 91 determines whether or not the number of acquired peak radii rp (n) is greater than or equal to a predetermined number. The predetermined number in this case is also a value N representing the number of measurement positions in one round. If the number of acquired peak radii rp (n) is smaller than the predetermined number, the controller 91 determines “No” in step S316, executes the processes of steps S306 and S308 described above, and executes step S304 or step S306. Return to S302.

By repeating the processing of steps S302 to S316 in this way, the number of acquired peak radii rp (n) increases and reaches a predetermined number, that is, at all reading points P (n, m) in the circumferential direction. When the peak radius rp (n) is acquired, the controller 91 determines “Yes” in step S316, and outputs an end command indicating the end of diffraction ring shape detection in step S318. Then, the controller 91 ends the execution of the diffraction ring shape detection program in step S320. By detecting the peak radius rp (n) at all the reading points P (n, m) in the circumferential direction, the shape of the diffraction ring is detected. The peak radius rp (n) (n = 1 to N) in the first diffraction ring measurement step is a first measurement value representing the shape of the diffraction ring used in the stress calculation step described later.

Here, we will return to the explanation of the diffraction ring reading program in FIGS. 7A and 7B. When the end command is output as described above, the controller 91 determines “Yes” in step S234 in FIG. 7A, and stops the focus servo control for the focus servo circuit 81 in step S240 in FIG. 7B. To stop the focus servo control. Next, the controller 91 controls the laser drive circuit 77 to stop the laser light irradiation by the laser light source 51 in step S242. Further, the controller 91 stops the operation of the A / D conversion circuit 83 and the rotation angle detection circuit 75 in step S244, and controls the feed motor control circuit 73 to stop the operation of the feed motor 42 in step S246. As a result, the imaging plate 31 is stopped, and the execution of the diffraction ring shape detection program is terminated in step S248. In this state, the operation of the position detection circuit 72 and the rotation of the imaging plate 31 are continued as before.

Next, the controller 91 executes the diffraction ring elimination program shown in FIG. Execution of the diffraction ring erasure program is started in step S400, and the controller 91 instructs the feed motor control circuit 73 to move the imaging plate 31 to the erasure start position in the diffraction ring erasure region in step S402. To do. The feed motor control circuit 73 drives and controls the feed motor 42 in cooperation with the position detection circuit 72 to move the imaging plate 31 to the erase start position. When the imaging plate 31 is at the erasing start position, the center of the visible light output from the LED 63 is located at a position smaller than the calculated diffraction ring reference radius R0 by a predetermined distance γ. Specifically, this position is output from the position detection circuit 72 when the distance from the center of the imaging plate 31 to the center of the visible light of the LED is Ry ′ in a state where the imaging plate 31 is at the drive limit position. This is the position where the position becomes R0-γ-Ry ′. Note that the predetermined distance γ is slightly larger than the predetermined distance α and is a position shifted with a margin from the radius of the imaged diffraction ring. Thereby, the imaged diffraction ring is surely erased by a process described later.

Next, in step S404, the controller 91 controls the LED drive circuit 84 to start irradiating the imaging plate 31 with visible light by the LED 63. Next, the controller 91 instructs the feed motor control circuit 73 to start and move the imaging plate 31 in step S406. The feed motor control circuit 73 drives and controls the feed motor 42 to move the imaging plate 31 from the erase start position to the bearing portion 44 side (right direction in FIG. 5) at a constant speed. Thereby, visible light from the LED 63 starts moving at a constant speed from the inner side to the outer side by a predetermined distance γ (γ> α) from the diffraction ring reference radius R 0 while rotating in the imaging plate 31.

After the process of step S406, the controller 91 inputs a position signal indicating the position of the imaging plate 31 from the position detection circuit 72 in step S408, and in step S410, the current position of the imaging plate 31 indicates the erase end position. Determine if it has exceeded. This end position is a position larger than the diffraction ring reference radius R0 by a predetermined distance γ. Specifically, the position output from the position detection circuit 72 is a position where R0 + γ−Ry ′. Then, until the current position of the imaging plate 31 exceeds the erasure end position, the controller 91 determines “No” in step S410, and repeatedly executes the processes of steps S408 and S410. Thereby, visible light from the LED 63 is irradiated from the diffraction ring reference radius R0 to the rotating imaging plate 31 from the inner side by a predetermined distance γ to the outer side by a predetermined distance γ, so that the diffraction formed by the diffracted X-rays. The ring is gradually erased from the inside.

If the current position of the imaging plate 31 exceeds the erasing end position, the controller 91 determines “Yes” in step S410, and stops the movement of the imaging plate 31 in the feed motor control circuit 73 in step S412. In step S414, the LED drive circuit 84 is instructed to stop the irradiation of visible light by the LED 63. Accordingly, the feed motor control circuit 73 stops the movement of the imaging plate 31 by stopping the operation of the feed motor 42. The LED drive circuit 84 stops the irradiation of visible light from the LED 63. In this state, the imaged diffraction ring is completely erased.

After the process of step S414, the controller 91 stops the operation of the position detection circuit 72 in step S416, and instructs the spindle motor control circuit 74 to stop the rotation of the imaging plate 31 in step S418. In response to this instruction, the spindle motor control circuit 74 stops the operation of the spindle motor 47 and stops the rotation of the imaging plate 31. After stopping the rotation of the imaging plate 31, the controller 91 ends the execution of the diffraction ring erasure program in step S420. When the execution of the diffraction ring erasing program is completed, the first diffraction ring measurement step is completed.

Next, the second diffractive ring measuring step will be described. The measurer moves the diffractive ring measuring apparatus by holding the handle 19 and moves the bottom wall 14 to the measuring object OB as shown in FIG. The inclined wall 17 is brought into contact with the vertical plane vp in a state in which the case 10 is placed on the horizontal plane hp in contact with the horizontal plane hp. Then, the measurer uses the input device 92 to instruct the start of residual stress measurement. Thereby, the controller 91 starts execution of the diffraction ring imaging program shown in FIG. Thereafter, the controller 91 executes the diffraction ring reading program shown in FIGS. 7A and 7B and the diffraction ring shape detection program shown in FIG. 8 in parallel, and also executes the diffraction ring elimination program shown in FIG. .

Also in this case, by executing the diffraction ring imaging program, a diffraction ring by diffraction X-rays from the measurement object OB is imaged on the imaging plate 31. In this case, the diffraction ring is orthogonal to the horizontal plane hp and is perpendicular to the vertical plane vp. 45 degrees with respect to the horizontal plane hp in the plane that forms 60 degrees, that is, with respect to the horizontal plane hp in a plane that is parallel to the direction that forms an angle of 30 degrees with the X direction in the horizontal plane hp and that is perpendicular to the horizontal plane hp. A diffraction ring is formed on the imaging plate 31 by X-rays irradiated to the horizontal plane hp from the direction of an angle of 45 degrees. The shape of the diffraction ring formed on the imaging plate 31 is detected by executing the diffraction ring reading program and the diffraction ring shape detection program. That is, the peak radii rp (n) at all the reading points P (n, m) in the circumferential direction are acquired. The peak radius rp (n) (n = 1 to N) in the second diffraction ring measurement step is a second measurement value representing the shape of the diffraction ring used in the stress calculation step described later. Thereafter, the diffraction ring imaged on the imaging plate 31 is completely erased by irradiation of visible light from the LED 63 by executing the diffraction ring erasing program. Then, when the execution of the diffraction ring erasing program is completed, the second diffraction ring measurement process ends.

Next, the stress calculation process will be described. The measurer instructs the controller 91 to execute the stress calculation program using the input device 92. The stress calculation program is shown in FIG. 10, and the controller 91 starts execution of the stress calculation program in step S500. After starting execution of the stress calculation program, the controller 91 in step S502, the peak radius rp (n) (n = 1 to N), that is, using the peak radius rp (n) (n = 1 to N) and the corresponding rotation angle (n−1) θo (n = 1 to N) at an incident angle of 45 degrees. The residual stress σx in the X direction described above due to the X-rays incident on the horizontal plane hp of the measurement object OB from the X direction is calculated using the cos α method. Next, in step S504, the controller 91 determines the peak radius rp (n) (n = 1 to N) as the first measured value and the corresponding rotation angle (n−1) θo (n = 1 to N), the above-described shear residual stress τxy caused by the X-ray incident on the horizontal plane hp of the measurement object OB from the X direction at an incident angle of 45 degrees is calculated using the cos α method.

Further, in step S506, the controller 91 uses the peak radius rp (n) (n = 1 to N) representing the shape of the diffraction ring, which is the second measurement value detected in the second diffraction ring measurement step. That is, using the peak radius rp (n) (n = 1 to N) and the corresponding rotation angle (n−1) θo (n = 1 to N), in the direction forming the angle θ with the X direction on the horizontal plane hp. A cos α method is used to calculate the residual stress σθ in the direction that forms an angle of θ with the X direction in the XY plane by X-rays that are incident on the horizontal plane hp at an angle of 45 degrees in a plane that is parallel and perpendicular to the horizontal plane hp calculate. In this embodiment, θ is an angle of the inclined wall 17 with respect to the front wall 11 and is 30 degrees. Regarding the calculation of residual stresses σx, τxy, σθ (σ30) by the cos α method, for example, Japanese Patent Application Laid-Open No. 2005-241308 and non-patent document “X-ray Evaluation of Residual Stress: Basics and Applications” (2006) July 29
Since it is a well-known technical matter described on page 317 and page 318 of Yokendo Co., Ltd.), detailed explanation is omitted.

After the process of step S506, the controller 91 calculates the residual stress σy in the Y direction described above using the residual stress σx, τxy, σθ (σ30) in step S508.

Here, the relationship between the residual stresses σx, τxy, σy and the residual stress σθ will be described. When the plane stress state as described above is represented by a tensor, it is represented by the following formula 1.

Since the residual stress in the direction inclined by the angle θ from the X direction obtained by coordinate conversion of the tensor expressed by the equation 1 by Cauchy's theorem is equal to the calculated residual stress σθ, the following equation 2 is established.

Then, the equation 2 is transformed as the following equation 3, and the residual stress σy is expressed as the following equation 4 using the residual stresses σx, τxy, σy, σθ.

Returning to the description of step S508 in FIG. 10 again, the angle θ is 30 degrees in the present embodiment. Therefore, in step S508, 30 degrees is substituted for the angle θ in the equation 4, and the step Substituting the residual stress σx, τxy, σθ (σ30) calculated in S502 to S506, the residual stress σy is calculated. After calculating the residual stress σy, the controller 91 ends the execution of the stress calculation program in step S510. When the execution of the stress calculation program ends, the stress calculation process ends.

Thus, according to the above-described embodiment, X-rays can be easily irradiated at a predetermined angle to the vicinity of the corner of the measurement object OB having the L-shaped cross section, and the vicinity of the corner of the horizontal plane hp of the measurement object OB. Since the residual stress σx in the X direction, the residual stress σy in the Y direction, and the residual stress τxy in the shear direction can be measured, the position near the corner of the measurement object OB having an L shape can be accurately inspected. . In particular, it is possible to accurately inspect an iron part or an iron member having an L-shaped cross section where the intersecting portions are joined by welding.

Further, as can be understood from the above description, according to the above embodiment, the measurement object OB having the horizontal plane hp and the vertical plane vp perpendicular to each other, that is, the measurement object OB having an L-shaped cross section cannot be moved easily. However, the X-ray diffractometer is conveyed with the handle 19, the bottom wall 14 is brought into contact with the horizontal plane hp of the measurement object OB, and the front wall 11 is brought into contact with the vertical plane vp of the measurement object OB. When the diffraction ring imaging program of FIG. 6 is executed, the X-ray emitter 10 is positioned from the direction perpendicular to the extending direction of the corner and at a predetermined angle with respect to the horizontal plane hp at a position near the corner in the horizontal plane hp. X-rays from the laser beam are irradiated with high precision, and an accurate diffraction ring is formed on the imaging plate 31. Further, when the bottom wall 14 is brought into contact with the horizontal plane hp of the measurement object OB and the inclined wall 17 is brought into contact with the vertical plane vp of the pair of measurement objects OB, the diffraction ring imaging program of FIG. 6 is executed. A direction that forms a predetermined angle with respect to the horizontal plane hp in a plane that forms a predetermined angle (30 degrees in the present embodiment) with respect to a plane orthogonal to the horizontal plane hp and the vertical plane vp at a position near the corner in the horizontal plane hp. X-rays from the X-ray emitter 10 are emitted with high accuracy, and a high-precision diffraction ring is formed on the imaging plate 31. That is, the measurer can irradiate X-rays at a predetermined angle with respect to each surface of the measurement object OB at a position near the corner of the measurement object OB with a simple operation, and provide a high-precision diffraction ring on the imaging plate 31. Can be formed.

Then, by executing the diffraction ring reading program of FIGS. 7A and 7B and the diffraction ring shape detection program of FIG. 8, the shape of the diffraction ring formed on the imaging plate 31 as described above is detected, and the stress calculation of FIG. When the program is executed, a highly accurate residual stress σx in a direction perpendicular to the extending direction of the corner of the measurement object OB at a position near the corner of the L-shaped measurement object OB and parallel to the horizontal plane hp is obtained. In addition to the calculation, a highly accurate residual stress σy in the direction of the intersecting line of the measurement object OB at the corner vicinity position is calculated. As a result, according to the above-described embodiment, X-rays can be irradiated from a predetermined direction with a simple operation, and the residual stresses σx and σy in the vicinity of the corners of the L-shaped measurement object OB can be accurately measured. Become.

Moreover, according to the said embodiment, since the table 30 was moved in parallel with the front wall 11, the back surface wall 12, the upper surface wall 13, and the bottom wall 15, the X-ray emitter 10, the table 30, the imaging plate 31, The case 10 accommodating the laser detection device 50 and the like can be formed into a simple rectangular parallelepiped shape, and the respective parts accommodated in the case 10 can be arranged in a compact manner, so that the case 10 can be reduced in size.

Further, according to the above embodiment, the case 10 is provided with the handle 19 for transportation, so that the transportation and movement of the X-ray diffraction measuring apparatus can be facilitated. Further, according to the above embodiment, the diffraction ring formed on the imaging plate 31 is erased with visible light from the LED 63 by executing the diffraction ring erasing program of FIG. 9, so that it is formed on the imaging plate 31. A new diffraction ring can be formed on the imaging plate 31 by easily erasing the existing diffraction ring, and formation of the diffraction ring on the imaging plate 31 by X-ray irradiation can be easily and repeatedly performed.

In the above description, the residual stress σx in the X direction, the residual stress σy in the Y direction, and the residual stress τxy in the shear direction are measured at positions near the corners of the horizontal plane hp of the measurement object OB having an L-shaped cross section. However, it is possible to measure the residual stress σx in the X direction, the residual stress σy in the Y direction, and the residual stress τxy in the shear direction at a position near the corner of the vertical surface vp of the measurement object OB having an L-shaped cross section. . In this case, in the first measurement step, the bottom wall 14 of the case 10 is brought into contact with the vertical surface vp of the measurement object OB, and the front wall 11 is brought into contact with the horizontal plane hp of the measurement object OB. In the second measurement step, the bottom wall 14 of the case 10 may be brought into contact with the vertical surface vp of the measurement object OB, and the inclined wall 17 may be brought into contact with the horizontal plane hp of the measurement object OB. According to this, since the X-ray from the X-ray irradiator 20 is irradiated from a predetermined direction to a position near the corner of the vertical surface vp of the measurement object OB having an L-shaped cross section, the horizontal plane hp described above and Similarly, the residual stress on the vertical plane vp can be measured.

Furthermore, the implementation of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.

In the above embodiment, the entire front wall 11, bottom wall 14, and inclined wall 17 are formed in a flat plate shape. However, the bottom wall 14 is brought into contact with the horizontal plane hp of the measurement object OB, the front wall 11 and the inclined wall 17 are brought into contact with the vertical surface vp of the measurement object OB, or the bottom wall 14 is brought into contact with the measurement object OB. The front wall 11, the bottom wall 14, or the inclined wall 17 may be used as long as the front wall 11 and the inclined wall 17 can be brought into contact with the vertical surface vp and the horizontal surface hp of the measurement object OB. You may provide a recessed part in a part of, or a hole.

In the above embodiment, the shape of the case 10 including the flat front wall 11, back wall 12, top wall 13, bottom wall 14, left side wall 15, right side wall 16, and inclined wall 17 is a rectangular parallelepiped shape. However, in order to irradiate the measurement object OB with X-rays by the X-ray emitter 10, the front wall 11, the inclined wall 17 and the bottom wall 14 are planar, and the front wall 11 and the inclined wall 17 are the bottom wall 14. The inclined wall 17 may be inclined at a predetermined angle (30 degrees in the present embodiment) in the inner direction of the case 10 with respect to the front wall 11. Therefore, the back wall 12, the top wall 13, the left side wall 16, and the right side wall 17, which are other parts of the case 10, may not be planar, and accordingly, the case 10 may not be particularly rectangular parallelepiped. .

In the above embodiment, the angle between the front wall 11 and the inclined wall 17, that is, the angle θ is set to 30 degrees. This is because the calculation of sin 2θ, sin ² θ, cos ² θ in the above equation 4 is easy. Thus, the calculation of Equation 4 can be easily performed. However, if the above equation 4 is used, the residual stress σy can be calculated at any angle, and therefore the angle θ formed by the front wall 11 and the inclined wall 17 can be set as appropriate. In this case, if the angle θ is too large, the table 30 and the imaging plate 31 will hit the inclined wall 17. If the angle θ is too small, the accuracy of the residual stress σy calculated by the above equation 4 is deteriorated. Therefore, the angle θ is preferably in the range of 20 to 50 degrees.

In the above embodiment, the X-ray irradiation direction is set to 45 degrees with respect to the bottom wall 14 of the case 10, but the diffracted X-rays must be blocked by the front wall 11, the bottom wall 14, and the inclined wall 17. The angle may be different from 45 degrees. If the measurement object OB is an iron part or an iron member, the angle of the diffracted X-ray with respect to the irradiated X-ray is about 24 degrees, so that the diffracted X-ray does not approach the front wall 11 and the bottom wall 14 too much. The X-ray irradiation direction may be set to an angle within the range of 35 to 55 degrees with respect to the bottom wall 14 of the case 10.

Further, in the above embodiment, the X-rays emitted from the X-ray emitter 20 and passing through the table 30 and the imaging plate 31 are slightly positioned on the back wall 12 side with respect to the intersection line between the front wall 11 and the bottom wall 14. To pass. However, instead of this, the X-rays may pass through a position slightly closer to the top wall 13 than the intersection line between the front wall 11 and the bottom wall 14. In this case, when the bottom wall 14 of the case 10 is brought into contact with the horizontal plane hp of the measurement object OB and the front wall 11 is brought into contact with the vertical surface vp of the measurement object OB, the bottom wall 14 of the case 10 is also moved. When the measurement object OB is brought into contact with the horizontal plane hp and the inclined wall 17 is brought into contact with the vertical surface vp of the measurement object OB, the X-ray emission position with respect to the measurement object OB is the corner of the measurement object OB. The vertical surface vp near the position is irradiated, and the residual stress near the corner of the vertical surface vp is measured. However, in this case, the angle formed with the X-ray vertical plane vp and the X-ray optical axis when the inclined wall 17 is brought into contact with the vertical plane vp of the measurement object OB are orthogonal to the vertical plane vp. The angle formed with the normal direction of the horizontal plane hp of the surface is not equal to the angle θ1 formed with the front wall 11 of the optical axis of the X-ray and the angle θ2 formed with the front wall 11 of the inclined wall 17 from the angles θ1 and θ2. It is necessary to calculate by calculation.

Also in this case, the bottom wall 14 of the case 10 is measured using the X-ray diffraction measurement apparatus according to the above-described embodiment as in the case of measuring the residual stress near the corner of the vertical plane vp. When the front wall 11 is brought into contact with the vertical plane vp of the object OB and the front wall 11 is brought into contact with the horizontal plane hp of the measurement object OB, the bottom wall 14 of the case 10 is brought into contact with the vertical plane vp of the measurement object OB. When the inclined wall 17 is brought into contact with the horizontal plane hp of the measurement object OB, the X-ray from the X-ray irradiator 20 is irradiated to a position near the corner of the horizontal plane hp of the measurement object OB. It is possible to measure the residual stress near the corners. In this case as well, the X plane of the plane perpendicular to the horizontal plane hp includes the angle formed with the horizontal plane hp of the X-ray and the optical axis of the X-ray when the inclined wall 17 is brought into contact with the horizontal plane hp of the measurement object OB. The angle formed with the direction needs to be calculated by calculation from the angle θ1 and the angle θ2.

Further, in the above embodiment, the residual stress σx in the direction perpendicular to the intersecting line direction of the measurement object OB at the position near the corner of the L-shaped measurement object OB and parallel to the horizontal plane hp, and the vicinity of the corner The residual stress σy in the direction of the intersecting line of the measurement object OB at the position was measured. However, if it is not necessary to measure the residual stress σy in the direction of the intersecting line of the measurement object OB in the vicinity of the corner, the bottom wall 14 is brought into contact with the horizontal plane hp of the measurement object OB, and a pair of inclined walls 17 are provided. It is not necessary to form a diffraction ring on the imaging plate 31 in contact with the vertical surface vp of the measurement object OB. Therefore, in this case, it is not necessary to provide the inclined wall 17 in the case 10. In this case, the processing of steps S504 to S508 in FIG. 10 is also unnecessary.

In the above embodiment, in order to measure the shape of the diffraction ring, the signal intensity S (n, m) and the radius r (n, m) each time the rotation angle of the imaging plate 31 reaches a predetermined rotation angle. I remembered. However, instead of this, the rotation angle θ (n, m), the signal intensity S (n, m), and the radius r (n, m) of the imaging plate 31 may be acquired and stored at predetermined time intervals. Good.

Further, in the above-described embodiment, the reading start position is determined using the light receiving position of the light receiving sensor 35, assuming an area in which the radius of the captured diffraction ring may deviate from the diffraction ring reference radius R0. did. However, the laser beam may always be irradiated to a certain region without using the diffraction ring reference radius R0. For example, the entire region of the imaging plate 31 may be irradiated with laser light. Similarly, the visible light emitted from the LED 63 may be constantly irradiated with visible light emitted from the LED 63 in a certain area. For example, the entire area of the imaging plate 31 may be irradiated with visible light from the LED 63. However, in this case, the measurement time is longer than in the above embodiment.

Further, in the above embodiment, the laser detection device 50 is controlled by the focus servo. However, when the imaging plate 31 is rotated, the variation in the distance between the light receiving surface of the imaging plate 31 and the objective lens 56 is minute. If so, focus servo control is unnecessary.

In the above embodiment, the laser light applied to the imaging plate 31 is a constant intensity laser light. Instead of this, a preset high level intensity and a preset low level laser light are used. A pulsed laser beam having repeated intensities may be used, and an instantaneous value of the SUM signal may be acquired at a timing when the intensity reaches a high level. In this case, a laser beam having a high level of intensity is instantaneously applied to a point at which the instantaneous value of the SUM signal of the imaging plate 31 is acquired. That is, in the state where the laser beam is directed to the point where the instantaneous value of the SUM signal is acquired, the intensity of the laser beam is at a low level, and almost no light is generated by the stimulated emission. Then, when approaching the point at which the instantaneous value of the SUM signal is obtained, the intensity of the laser beam becomes high and light due to the stimulated emission is generated. When laser light with a high level of intensity is always radiated, the intensity of the light decreases due to the continued generation of light due to the stimulated light emission. Thus, the instantaneous value of the SUM signal can be acquired.

Claims

An X-ray emitter that emits X-rays toward the measurement object;
A table formed with a through-hole through which X-rays pass in the center;
Mounted on the table, allows X-rays to pass through the central portion, and has a light-receiving surface for receiving X-ray diffracted light diffracted by the measurement object, and records a diffraction ring that is an image of diffracted light An imaging plate;
It has a laser light source that emits laser light and a photodetector that receives the laser light, and irradiates the light receiving surface of the imaging plate with the laser light and receives and emits the light emitted from the imaging plate by the laser light irradiation. A laser detection device that outputs a light reception signal corresponding to the intensity;
A rotation mechanism for rotating the table around the central axis of the through hole;
Between the X-ray emission position through which the X-ray from the X-ray emitter passes through the table and the imaging plate, and the laser light irradiation position at which the imaging plate is irradiated with laser light from the laser detection device, A moving mechanism for moving the table;
A case housing the X-ray emitter, the table, the imaging plate, the laser detection device, the rotation mechanism, and the moving mechanism;
The X-ray emitted from the X-ray emitter passes through the case to irradiate the measurement object, and the diffracted X-ray emitted from the measurement object by the irradiation of the X-ray passes through the case to perform the imaging. An X-ray diffraction measurement device that leads to a plate,
The case has a flat first flat wall and a second flat wall that are orthogonal to each other,
The optical axis of the X-ray emitted from the X-ray emitter is included in a plane orthogonal to the first plane wall and the second plane wall, respectively, and an intersection line of the first plane wall and the second plane wall The X-ray emitter is disposed in the case so that X-rays are emitted from a direction inclined by a first predetermined angle with respect to the second plane wall at a position near
With respect to the measurement object having a pair of plane parts orthogonal to each other, the first plane wall is brought into contact with one plane part of the pair of plane parts, and the second plane wall is brought into contact with the pair of plane parts. The X-ray emitter from the direction perpendicular to the crossing line of the pair of planar parts at a position in the vicinity of the crossing line of the pair of planar parts in the one or other plane part when being brought into contact with the other planar part. X-ray diffraction measuring apparatus adapted to emit X-rays from
The X-ray diffraction measurement apparatus according to claim 1,
The case further includes a flat inclined wall that is orthogonal to the first plane wall and is inclined at a second predetermined angle in an inner direction of the case with respect to the second plane wall,
When the first planar wall is brought into contact with one planar portion of the pair of planar portions of the measurement object and the inclined wall is brought into contact with the other planar portion of the pair of planar portions, the one or the other A plane that includes the optical axis of the X-ray emitted from the X-ray emitter and is orthogonal to the first plane wall at a position near the intersecting line of the pair of plane portions in the plane portion of An X-ray diffraction measuring apparatus configured to emit X-rays from the X-ray emitter in a state of intersecting at a second predetermined angle with respect to a plane orthogonal to the intersecting line.
3. The X-ray diffraction measurement apparatus according to claim 2, wherein the second predetermined angle is in a range of 20 degrees to 50 degrees.
The X-ray diffraction measurement apparatus according to any one of claims 1 to 3, wherein the first predetermined angle is in a range of 35 degrees to 55 degrees.
The X-ray diffraction measurement apparatus according to any one of claims 1 to 4, wherein a moving direction of the table by the moving mechanism is a direction of an intersecting line between the first planar wall and the second planar wall.
The X-ray diffraction measurement apparatus according to any one of claims 1 to 5, wherein a handle for transportation is provided in the case.
The X-ray diffraction measurement apparatus according to any one of claims 1 to 6, further comprising a diffraction ring erasing unit that erases a diffraction ring formed on the imaging plate.
In addition to the X-ray diffraction measurement device according to claim 1,
The rotation mechanism is controlled to rotate the table, and the movement mechanism is controlled to move the table, while the laser detection device is controlled to detect the irradiation position of the light receiving surface of the imaging plate. Diffracting ring reading means for reading the diffracting ring formed on the imaging plate by inputting the light receiving signal from the laser detection device and irradiating while processing the detected irradiation position and the input light receiving signal;
With respect to the measurement object having a pair of plane parts orthogonal to each other, the first plane wall is brought into contact with one plane part of the pair of plane parts, and the second plane wall is brought into contact with the pair of plane parts. Data representing a diffraction ring formed on the imaging plate by irradiation with X-rays from the X-ray emitter in contact with the other plane part, using the data read by the diffraction ring reading means , Residual stress at a position in the vicinity of the intersection line of the pair of plane portions in the one or the other plane portion, and remaining in a direction perpendicular to the intersection line of the pair of plane portions and parallel to the first plane wall An X-ray diffraction measurement system comprising a residual stress calculation means for calculating stress.
In addition to the X-ray diffraction measurement apparatus according to claim 2,
The rotation mechanism is controlled to rotate the table, and the movement mechanism is controlled to move the table, while the laser detection device is controlled to detect the irradiation position of the light receiving surface of the imaging plate. Diffracting ring reading means for reading the diffracting ring formed on the imaging plate by inputting the light receiving signal from the laser detection device and irradiating while processing the detected irradiation position and the input light receiving signal;
With respect to the measurement object having a pair of plane parts orthogonal to each other, the first plane wall is brought into contact with one plane part of the pair of plane parts, and the second plane wall is brought into contact with the pair of plane parts. Data representing a diffraction ring formed on the imaging plate by irradiation with X-rays from the X-ray emitter in contact with the other plane part, the data read by the diffraction ring reading means, X-rays from the X-ray emitter are brought into contact with one flat portion of the pair of flat portions and the inclined wall is brought into contact with the other flat portion of the pair of flat portions. The data representing the diffraction ring formed on the imaging plate by irradiation of the data, and using the data read by the diffraction ring reading means, the intersection line of the pair of plane parts in the one or the other plane part Proximity A residual stress calculating means for calculating a residual stress in a direction perpendicular to an intersection line of the pair of plane portions and parallel to the first plane wall and a residual stress in the direction of the intersection line. X-ray diffraction measurement system.