JP2014066545A - X-ray diffraction measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate measurement of triaxial residual stresses even when an object to be measured is large or fixed, by allowing an X-ray diffraction measurement device to be easily transported and allowing the direction of X-rays to be easily changed at a measurement position.SOLUTION: In an X-ray diffraction measurement device, a case 60 accommodates therein: an X-ray emitter 10; an imaging plate 21 on which a diffraction ring is formed by irradiating X-rays to an object OB to be measured; and a laser detector 40 for measuring a shape of the diffraction ring. The case 60 has an undersurface wall 64 to have surface contact with a top surface of the object OB to be measured, an inclined surface wall 67 continuing from the undersurface wall 64, and an open hole 64a disposed across the intersection of the undersurface wall 64 and the inclined surface wall 67 for transmitting X-rays. An angle formed between an optical axis of X-rays and a normal of the inclined surface wall 67 is set to a predetermined angle, and the optical axis of X-rays is set to be parallel to the normal of the undersurface wall 64.

Description

  The present invention relates to an X-ray diffraction measurement apparatus that irradiates a measurement object with X-rays and measures a diffraction ring formed on the surface of an imaging plate by X-rays diffracted by the measurement object.

  Conventionally, as shown in Patent Document 1 below, an X-ray diffraction measuring apparatus is known which is assembled on a rail so as to be movable in the extending direction and measures the residual stress on the upper surface of the rail. This device irradiates X-rays on the upper surface of the rail, which is the measurement object, at a predetermined angle, and receives the X-rays diffracted by the measurement object (hereinafter referred to as diffracted X-rays) with a photosensitive imaging plate. Then, the shape of an annular X-ray diffraction image (hereinafter referred to as a diffraction ring) formed on the imaging plate is measured. Then, the shape of the measured diffraction ring is analyzed by the cos α method, and the residual stress of the measurement object is calculated. According to this cos α method, the residual stress in the direction of the intersection between the plane including the X-ray emission axis, the normal line of the measurement object, and the upper surface of the measurement object (hereinafter referred to as residual normal stress) is calculated. .

  Further, in Patent Document 2 below, X-rays are obliquely inclined from the positive and negative directions of the X direction and the Y direction on the upper surface of the measurement object, that is, four orthogonal directions (φ0 = 0 degree, 90 degrees, 180 degrees, 270 degrees). A method of measuring residual stress in the three-axis (X-axis, Y-axis, and Z-axis) directions by the cos α method is shown from the shapes of diffraction rings formed by four measurements of irradiating the film. Further, in Patent Document 2, X-rays are obliquely irradiated on the upper surface of the measurement object from the X direction and the Y direction, that is, two orthogonal directions (φ0 = 0 degree, 90 degrees), and then measured. Three times (X-axis, Y-axis, and Z-axis) are obtained from the shape of each diffraction ring formed by three measurements of irradiating the upper surface of the object with X-rays from the normal direction (Z direction). A method for measuring the residual stress in the) direction is also shown.

JP-A-2005-241308 JP 2011-27550 A

  If the residual stress component in the normal direction of the upper surface of the measurement object is a plane stress state that can be regarded as “0”, the biaxial residual normal stress composed of the X axis and the Y axis that are parallel to the upper surface and orthogonal to each other The measurement object can be evaluated by measuring only σx, σy and the residual shear stress τxy. However, some measurement objects have large residual stress components in the normal direction of the upper surface of the measurement object. In this case, the X axis and the Y axis are parallel to the upper surface of the measurement object and orthogonal to each other. In addition, it is necessary to measure residual normal stresses σx, σy, σz and residual shear stresses τxy, τxz, τyz, which are triaxial residual stresses composed of the Z axis that is the normal direction of the upper surface of the measurement object. In addition, there are measuring objects that need to measure the triaxial residual stress as described above, which are large or fixed.

  The X-ray diffraction measurement apparatus disclosed in Patent Document 1 irradiates the measurement object with X-rays from a certain direction, that is, an oblique direction in a plane perpendicular to the extending direction of the rail. Residual stress cannot be measured. Further, although the X-ray diffraction measurement apparatus shown in Patent Document 1 is small, it is not configured to be transported by humans, and this X-ray diffraction measurement apparatus is made of a material that is a measurement object. Since it cannot be easily carried to a place, the residual stress of a large measurement object or a fixed measurement object cannot be measured. Moreover, although the method of measuring the triaxial residual stress is shown in the above-mentioned patent document 2, in order to measure the triaxial residual stress in a large measurement object or a fixed measurement object, There is a need for an X-ray diffractometer that can be easily carried by a person or that can easily change the direction of X-rays at a measurement location, but such an apparatus is not shown.

  The present invention has been made in order to solve the above-described problems, and the object thereof is to be able to easily transport to a measurement object and to change the X-ray direction easily at the measurement position. Even if the object is large or fixed, the shape of the diffraction ring formed on the surface of the imaging plate by irradiating the measurement object with X-rays in a predetermined direction and diffracting with the measurement object It is an object to provide an X-ray diffraction measurement apparatus that can easily measure triaxial residual stress. 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 (10) that emits X-rays toward a measurement object (OB) and a through-hole that allows X-rays to pass through in the center are formed. A table (20) is attached to the table and has a light-receiving surface that allows X-rays to pass through at the center and receives X-ray diffracted light diffracted by the measurement object, and is an image of diffracted light. An imaging plate (21) for recording the diffraction ring, a laser light source for emitting laser light, and a light receiver for receiving the laser light, and irradiating the light receiving surface of the imaging plate with the laser light and imaging by irradiating the laser light A laser detection device (40) for receiving light emitted from the plate and outputting a light reception signal corresponding to the received light intensity; a rotation mechanism (37) for rotating the table around the central axis of the through hole; A moving mechanism (31-33) that moves relative to the laser detector in a direction parallel to the light receiving surface of the mating plate, an X-ray emitter, a table, an imaging plate, a laser detector, a rotating mechanism, and a moving mechanism An X-ray diffraction measurement device including a case (60) accommodated, the case being a planar first installation wall for placing the X-ray diffraction measurement device in surface contact with a measurement object (67), a planar second installation wall (64) for placing the X-ray diffraction measurement device in surface contact with the measurement object, and the first installation wall and the second installation wall. An opening (64a) that is formed across the intersection and allows the X-rays emitted from the X-ray emitter to pass therethrough, and the normal of the first installation wall and the X-rays emitted from the X-ray emitter The angle formed by the optical axis is measured when the measurement object is irradiated with X-rays. Set to a predetermined angle of X-rays diffracted from the object is emitted is to set parallel to the optical axis of the emitted X-rays with respect to the normal of the second installation wall and the X-ray emission device.

  In this case, the predetermined angle may be an angle within a range of 30 degrees to 45 degrees, for example. The case has a lower surface wall perpendicular to the optical axis direction of the X-ray from which the X-ray is emitted from the X-ray emitter, and an inclined surface wall is formed at one end portion of the lower surface wall to be inclined with respect to the lower surface wall. The inclined wall may be the first installation wall and the lower wall may be the second installation wall. The case may be formed in a rectangular parallelepiped shape, and an inclined surface wall may be provided at a corner of one end of the lower surface wall in the moving direction of the table.

  In the present invention configured as described above, the operator transports the X-ray diffraction measurement apparatus to a place where the measurement object is located, and starts the first measurement. In this first measurement, the X-ray diffraction measurement device is placed on the measurement object by bringing the first installation wall into surface contact with the measurement object. In this state, if the measurement object is irradiated with X-rays from the X-ray emitter through an opening provided across the intersection of the first installation wall and the second installation wall, the upper surface of the measurement object A diffraction ring is formed on the imaging plate in a state where the normal line and the optical axis of the X-ray form a predetermined angle. Then, when the imaging plate is moved and rotated together with the table by operating the rotating mechanism and the moving mechanism in a state where the laser detection device is operated, the shape of the diffraction ring formed on the imaging plate is measured.

  Next, as the second measurement, the X-ray diffractometer is used for the first measurement on the measurement object while keeping the first installation wall in surface contact with the measurement object. If the diffraction ring is formed on the imaging plate and the shape of the diffraction ring is measured in the same manner as in the first measurement, the X-ray is measured on the upper surface of the measurement object with respect to the first measurement. The shape of the diffraction ring formed on the imaging plate is measured in a state where the irradiation direction is rotated 90 degrees.

  Next, as the third measurement, the X-ray diffraction measurement device is placed on the measurement object by bringing the second installation wall into surface contact with the measurement object, and the X-ray from the X-ray emitter is placed. Is irradiated to the measurement object through an opening provided across the intersection of the first installation wall and the second installation wall, by irradiating X-rays from the vertical direction to the upper surface of the measurement object. A diffractive ring is formed in the imaging plate. Then, if the shape of the formed diffraction ring is measured in the same manner as the first and second measurements, the diffraction plate is formed on the imaging plate in a state where X-rays are irradiated from the vertical direction on the upper surface of the measurement object. The shape of the diffraction ring is measured.

  Then, if the residual stress of the measurement object is calculated according to the cos α method using the measurement results of the first to third diffraction ring shapes, 3 consisting of the X axis, the Y axis, and the Z axis orthogonal to each other. The residual stress of the shaft (residual normal stress σx, σy, σz and residual shear stress τxy, τxz, τyz) can be obtained. As a result, according to the features of the present invention, the X-ray direction can be easily changed at the measurement position while being easily transported to the measurement object, and the measurement object is large or fixed. Even so, an X-ray diffraction measuring apparatus capable of easily measuring the triaxial residual stress is realized.

  Another feature of the present invention is that an erasing means (53) for erasing the diffraction ring recorded on the imaging plate is further provided in the case. According to this, since the diffraction ring can be deleted every time the diffraction ring is formed and the shape is measured, it is convenient when the diffraction ring is formed and the shape is measured a plurality of times.

  Another feature of the present invention is that the case is further provided with support legs (68a, 68b) for maintaining the first installation wall in surface contact with the object to be measured. In this case, the support leg may be, for example, a folding type or an advancing / retracting type. According to this, it is possible to reliably maintain the state in which the first installation wall is brought into surface contact with the measurement object and the X-ray diffraction measurement device is placed on the measurement object with a simple configuration.

  Another feature of the present invention is that the case is further provided with a handle (69) for conveyance. In this case, the handle may be provided on the upper surface of the case, for example. According to this, since the X-ray diffraction measurement device can be transported by holding the handle, the transport of the X-ray diffraction measurement device becomes easier.

  Furthermore, another feature of the present invention is that the reflected light of the light emitted through the first installation wall or the second installation wall is detected, and the first installation wall or the second installation is based on the intensity of the reflected light. Contact detecting means (55, 56, S112) for detecting the presence or absence of surface contact between the wall and the upper surface of the measurement object is provided. According to this, it is possible to determine whether the first installation wall is in surface contact with the surface of the measurement object, or whether the second installation wall is in surface contact with the surface of the measurement object. The mode of the measurement process can be changed between the case where is in surface contact with the upper surface of the measurement object and the case where the second installation wall is in surface contact with the upper surface of the measurement object. Moreover, if both the surface contact state with respect to the upper surface of the measurement object of the first installation wall and the surface contact state with respect to the upper surface of the measurement object of the second installation wall are detected, the first installation wall and Both of the second installation walls can also detect a state where they are not in surface contact with the surface of the measuring object, and in this case, the X-ray emission by the X-ray emitter can be stopped. Become.

1 is an overall schematic diagram showing an X-ray diffraction measurement system including an X-ray diffraction measurement apparatus according to an embodiment of the present invention. It is an enlarged view of the X-ray-diffraction measuring apparatus of FIG. 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. It is a flowchart which shows the diffraction ring deletion program performed by the controller of FIG. It is a flowchart which shows the stress calculation program performed by the controller of FIG. 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. It is a schematic perspective view of the light-shielding member for an X-ray diffraction measuring apparatus. It is a state figure which shows the storage or conveyance state of the X-ray-diffraction measuring apparatus of FIG. It is a state diagram which shows the diffraction ring imaging state in the state which inclined the X-ray-diffraction measuring apparatus of FIG. It is a state diagram which shows the diffraction ring reading state in the state which inclined the X-ray-diffraction measuring apparatus of FIG. It is a state diagram which shows the diffraction ring imaging state in the state which leveled the X-ray-diffraction measuring apparatus of FIG. It is a state diagram which shows the diffraction ring reading state in the state which leveled the X-ray-diffraction measuring apparatus of FIG. It is explanatory drawing for demonstrating the coordinate system in the X-ray irradiation by an X-ray-diffraction measuring apparatus.

  A configuration of an X-ray diffraction measurement system including an X-ray diffraction measurement apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In order to evaluate the residual stress of the measurement object OB, this X-ray diffraction measurement system irradiates the measurement object OB with X-rays and diffraction formed by diffracted X-rays from the measurement object OB due to the irradiation. Detect the shape of the ring. The measurement object OB is, for example, a flat iron material that has been shot peened.

  The X-ray diffraction measurement apparatus includes an X-ray emitter 10 that emits X-rays, a table 20 for mounting an imaging plate 21 on which a diffraction ring is formed by diffracted X-rays, and a table driving mechanism that rotates and moves the table 20. 30, a laser detection device 40 for measuring a diffraction ring formed on the imaging plate 21, an X-ray emitter 10, a table 20, a table driving mechanism 30, a laser detection device 40, a light emitting element (LED) 55, and light reception And a case 60 for housing a photo detector 56. Further, the case 60 is connected to the X-ray emitter 10, the table driving mechanism 30, the laser detection device 40, the light emitting element 55, the light receiver 56, and the like to control the operation and to input a detection signal. Various circuits are also built in, and various circuits indicated by a two-dot chain line shown outside the case 60 in FIG. 1 are accommodated within a two-dot chain line in the case 60. In FIG. 1 and FIG. 2, circuit boards, electric wires, fixtures, air cooling fans, and the like are omitted.

  The case 60 is formed in a rectangular parallelepiped shape having a flat front wall 61, a rear wall 62, an upper wall 63, a lower wall 64, a left side wall 65, and a right side wall 66 (not shown), and the front wall 61 and the lower wall. An inclined surface wall 67 is provided so as to obliquely cut 64 corners. The inclined surface wall 6 is inclined with respect to the lower surface wall 64 by an inclination angle Ψ described later in detail. A circular through-hole (opening) 64a centering on the intersection line is formed in the intersection line portion where the lower wall 64 and the inclined wall 67 intersect, and at the central portion of the left wall 65 and the right wall 66. And an X-ray (X-ray emitted from the X-ray emitter 10) for forming a diffraction ring is passed through the through hole 64a. ing. Then, the inclined surface wall 67 and the lower surface wall 64 are brought into close contact, that is, in surface contact with the surface (upper surface) of the measurement object OB, respectively, and the measurement object OB is irradiated with X-rays to form diffraction rings on the imaging plate 21, respectively. It is supposed to be.

  On the left and right side walls 65, 66, upper ends of support legs 68a, 68b (the support legs 68b are not shown) are rotatably assembled. These support legs 68a and 68b are folded so as to be parallel to the lower surface wall 64 and stored in close contact with the left and right side walls 65 and 66 when the X-ray diffraction measuring apparatus is stored and transported. When the inclined surface wall 67 of the X-ray diffractometer is brought into surface contact with the upper surface of the measurement object OB, it is rotated and stretched in the vertical direction with respect to the lower surface wall 64, and the lower end portion is brought into close contact with the measurement object OB. The face wall 67 is maintained in close contact with the surface of the measurement object OB. The supporting legs 68a and 68b may be either one as long as the case 60 can be maintained in the state shown in FIG. A handle 69 is attached to the upper surface wall 63 of the case 60 so that the user can carry the X-ray diffraction measuring apparatus by holding the handle 69 by hand. Note that the computer apparatus 90 and the high-voltage power supply 95 described later are the only apparatuses that are simultaneously transported when the X-ray diffraction measurement apparatus is transported.

  The X-ray emitter 10 is formed in a long shape, extends in the front-rear direction at the upper part in the case 60 and is fixed to the case 60, is supplied with a high voltage from a high-voltage power supply 95, Controlled by the line control circuit 71, X-rays are emitted downward. The optical axis of the X-ray emitted from the X-ray emitter 10 is perpendicular to the upper surface wall 63 and the lower surface wall 64 of the case 60, and the front wall 61, the rear wall 62, and the left and right side walls 65, 66 of the case 60. The direction of the exit 11 of the X-ray emitter 10 is set to be parallel to the X-ray emitter 10. Therefore, the optical axis of the X-ray forms an inclination angle Ψ with respect to the normal line of the inclined surface wall 67 and is parallel to the normal line of the lower surface wall 64. The inclination angle Ψ is a predetermined angle within a range of 30 degrees to 45 degrees, for example.

  The X-ray control circuit 71 is controlled by a controller 91 that configures a computer device 90 described later, and is supplied to the X-ray emitter 10 so that X-rays with a certain intensity are emitted from the X-ray emitter 10. Control current and drive voltage. In addition, the X-ray emitter 10 includes a cooling device (not shown), and the X-ray control circuit 71 also controls a drive signal supplied to the cooling device. Thereby, the temperature of the X-ray emitter 10 is kept constant.

  The table driving mechanism 30 includes a moving stage 31 below the X-ray emitter 10. The moving stage 31 is within the plane formed by the optical axis of the X-ray emitted from the X-ray emitter 10 and the normal line of the measurement object OB by the feed motor 32 and the screw rod 33, and the X-ray light. It can move in the direction perpendicular to the axis. The feed motor 32 is fixed in the table driving mechanism 30 and cannot move with respect to the case 60. The screw rod 33 extends in a direction perpendicular to the optical axis of the X-ray emitted from the X-ray emitter 10, and one end thereof is connected to the output shaft of the feed motor 32. The other end portion of the screw rod 33 is rotatably supported by a bearing portion 34 provided in the table drive mechanism 30. The moving stage 31 is sandwiched between a pair of opposed plate-like guides 35 and 35 fixed in the table driving mechanism 30, respectively, and can move along the axial direction of the screw rod 33. ing. That is, when the feed motor 32 is driven forward or backward, the rotational motion of the feed motor 32 is converted into the linear motion of the moving stage 31. An encoder 32 a is incorporated in the feed motor 32. The encoder 32 a outputs a pulse train signal that alternately switches between a high level and a low level to the position detection circuit 72 and the feed motor control circuit 73 every time the feed motor 32 rotates by a predetermined minute rotation angle.

  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 32 to move the moving stage 31 to the feed motor 32 side. When the pulse signal output from the encoder 32a is not input, the position detection circuit 72 outputs a signal indicating that the moving stage 31 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 32. The above movement limit position is set as the origin position of the moving stage 31. Therefore, the position detection circuit 72 outputs a position signal representing “0” when the moving stage 31 moves in the upper left direction in FIGS. 1 and 2 and reaches the movement limit position, and the movement stage 31 moves to the movement limit position. When moving from right to left, a signal indicating 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 31 from the controller 91, the feed motor control circuit 73 drives the feed motor 32 forward or backward in accordance with the set value. The position detection circuit 72 counts the number of pulses of the pulse signal output from the encoder 32a. Then, the position detection circuit 72 calculates the current position (movement distance x from the movement limit position) of the moving stage 31 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 32 until the current position of the moving stage 31 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 31 from the controller 91. Then, the moving speed of the moving stage 31 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 32a, and the calculated moving speed of the moving stage 31 becomes the moving speed input from the controller 91. The feed motor 32 is driven.

  The upper ends of the pair of guides 35 are connected by a plate-like upper wall 36. A through hole 36 a is provided in the upper wall 36, and a distal end portion of the emission port 11 of the X-ray emitter 10 is inserted into the through hole 36 a. The positions of the X-ray emitter 10 and the moving stage 31 are set so that the tip of the emission port 11 of the X-ray emitter 10 does not contact the moving stage 31.

  A spindle motor 37 is assembled to the moving stage 31. In the spindle motor 37, an encoder 37a similar to the encoder 32a is incorporated. That is, the encoder 37a outputs a pulse train signal that alternately switches between a high level and a low level to the spindle motor control circuit 74 and the rotation angle detection circuit 75 each time the spindle motor 37 rotates by a predetermined minute rotation angle. Furthermore, the encoder 37a outputs an index signal that switches from the low level to the high level only for a predetermined short period to the controller 91 and the rotation angle detection circuit 75 every time the spindle motor 37 makes one rotation.

  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 37 from the controller 91. Then, the rotational speed of the spindle motor 37 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 37a, and the drive signal is input to the spindle so that the calculated rotational speed becomes the rotational speed input from the controller 91. Supply to the motor 37. The rotation angle detection circuit 75 counts the number of pulses of the pulse train signal output from the encoder 37a, calculates the rotation angle of the spindle motor 37, that is, the rotation angle θp of the imaging plate 21 using the count value, and sends it to the controller 91. Output. When the rotation angle detection circuit 75 receives the index signal output from the encoder 37a, 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.

  The table 20 is formed in a circular shape and is fixed to the tip of the output shaft of the spindle motor 37. The center axis of the table 20 coincides with the center axis of the output shaft of the spindle motor 37. The table 20 has a protruding portion 22 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 22. The central axis of the protruding portion 22 coincides with the central axis of the output shaft of the spindle motor 37. An imaging plate 21 is attached to the lower surface of the table 20. The imaging plate 21 is a circular plastic film whose surface is coated with a phosphor. A through-hole 21a is provided at the center of the imaging plate 21, and the imaging plate 21 is fixed by screwing a nut-like fixture 23 through the projection 22 through the projection 22 and passing through the projection 22. It is sandwiched between the tool 23 and the table 20 and fixed. The fixture 23 is a cylindrical member, and a thread corresponding to the thread of the protrusion 22 is formed on the inner peripheral surface.

  The imaging plate 21 is driven by a feed motor 32 and moves together with the moving stage 31, the spindle motor 37, and the table 20 from the origin position to the diffraction ring imaging position for imaging the diffraction ring. The imaging plate 21 is driven by the spindle motor 37 and rotated while being driven by the feed motor 32, and in the diffraction ring reading area for reading the imaged diffraction ring together with the moving stage 31, the spindle motor 37 and the table 20, and It moves in the diffractive ring erasing region that erases the diffractive ring. In this case, in the movement of the imaging plate 21, the central axis of the imaging plate 21 is maintained within a plane formed by the optical axis of the X-ray emitted from the X-ray emitter 10 and the normal line of the measurement object OB. In a leaned state, it moves in a direction perpendicular to the optical axis of the X-ray.

  The moving stage 31, the output shaft of the spindle motor 37, the table 20, the imaging plate 21, and the fixture 23 are each provided with a through hole through which the X-ray emitted from the X-ray emitter 10 passes. The central axes of these through holes coincide with the rotation axis of the table 20. That is, when the central axis of these through holes coincides with the optical axis of the X-ray emitted from the X-ray emitter 10, the X-ray is irradiated onto the measurement object OB. Thus, the position of the imaging plate 21 when irradiating the measurement object OB with X-rays is the diffraction ring imaging position.

  Below the feed motor 32, a light receiving sensor 25 (for example, an X-ray CCD) including a plurality of light receiving elements that receive X-rays reflected by the measurement object OB is assembled. The light receiving sensor 25 is sufficiently separated from the measurement object OB and the imaging plate 21 toward the feed motor 32. Thereby, when the inclined surface wall 67 is brought into surface contact with the upper surface of the measurement object OB and the imaging plate 21 is in the diffraction ring imaging position, the light receiving sensor 25 can directly receive the X-ray reflected by the measurement object OB. . In this state, the light receiving surface of the light receiving sensor 25 is parallel to the surface of the measurement object OB. The light receiving position of the X-ray on the light receiving surface of the light receiving sensor 25 corresponds to the height of the measurement object OB. In other words, this corresponds to the distance between the imaging plate 21 and the measurement object OB. The light receiving sensor 25 outputs a light receiving signal received by each light receiving element to the sensor signal extracting circuit 76.

  The sensor signal extraction circuit 76 starts to operate in response to a command from the controller 91, calculates a peak position of the light reception signal on the light receiving surface of the light receiving sensor 25 using the light receiving signal input from the light receiving sensor 25, and indicates a light receiving position. It outputs to the controller 91 as a position signal.

  The laser detection device 40 irradiates the imaging plate 21 that images the diffraction ring with laser light, and detects the intensity of the light incident from the imaging plate 21. The laser detection device 40 is sufficiently separated from the measurement object OB and the imaging plate 21 at the diffraction ring imaging position toward the feed motor 32. That is, when the imaging plate 21 is at the diffraction ring imaging position, X-rays diffracted by the measurement object OB are not blocked by the laser detection device 40. The laser detection device 40 includes a laser light source 41, a collimating lens 42, a reflecting mirror 43, a polarizing beam splitter 44, a ¼ wavelength plate 45, and an objective lens 46.

  The laser light source 41 is controlled by the laser driving circuit 77 and emits laser light that irradiates the imaging plate 21. The laser drive circuit 77 is controlled by the controller 91 and controls and supplies a drive signal so that laser light having a predetermined intensity is emitted from the laser light source 41. The laser drive circuit 77 inputs a light reception signal output from a light receiver (photo detector) 52 described later, and controls a drive signal output to the laser light source 41 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 21 is kept constant.

  The collimating lens 42 converts the laser light emitted from the laser light source 41 into parallel light. The reflecting mirror 43 reflects the laser light converted into parallel light by the collimating lens 42 toward the polarization beam splitter 44. The polarization beam splitter 44 transmits most of the laser light (for example, 95%) incident from the reflecting mirror 43 as it is. The quarter wavelength plate 45 converts the laser light incident from the polarization beam splitter 44 from linearly polarized light to circularly polarized light. The objective lens 46 condenses the laser light incident from the quarter wavelength plate 45 on the surface of the imaging plate 21. The optical axis of the laser light emitted from the objective lens 46 is in a plane formed by the optical axis of the X-ray emitted from the X-ray emitter 10 and the normal line of the measurement object OB. The direction is parallel to the optical axis, that is, the direction perpendicular to the moving direction of the moving stage 31.

  A focus actuator 47 is assembled to the objective lens 46. The focus actuator 47 is an actuator that moves the objective lens 46 in the optical axis direction of the laser light. The objective lens 46 is located at the center of the movable range when the focus actuator 47 is not energized.

  When the laser beam condensed by the objective lens 46 is irradiated onto the surface of the imaging plate 21 where the diffraction ring is imaged, a photo-stimulated luminescence phenomenon occurs. That is, after imaging the diffraction ring and irradiating the imaging plate 21 with laser light, the phosphor of the imaging plate 21 is light corresponding to the intensity of the diffracted X-ray and has a wavelength shorter than the wavelength of the laser light. To emit. The laser beam irradiated and reflected on the imaging plate 21 and the light emitted from the phosphor pass through the objective lens 46 and the quarter wavelength plate 45 and are reflected by the polarization beam splitter 44. A condenser lens 48, a cylindrical lens 49, and a light receiver (photo detector) 50 are provided in the reflection direction of the polarization beam splitter 44. The condensing lens 48 condenses the light incident from the polarization beam splitter 44 on the cylindrical lens 49. The cylindrical lens 49 causes astigmatism in the transmitted light. The light receiver 50 is composed of four divided light receiving elements composed of four identical square light receiving elements separated by a dividing line, and 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 of the light is output to the amplification circuit 78 as a light reception signal (a, b, c, d).

  The amplification circuit 78 amplifies the light reception signals (a, b, c, d) output from the light receiver 50 with the same amplification factor, and generates light reception signals (a ′, b ′, c ′, d ′). And 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 21.

  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 47 in accordance with the focus servo signal to displace the objective lens 46 in the optical axis direction of the laser light. In this case, by generating a focus servo signal so that the value of the focus error signal (a ′ + c ′) − (b ′ + d ′) is always a constant value (for example, zero), a laser is applied to the surface of the imaging plate 21. 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 light reflected by the imaging plate 21 and the intensity of the light generated by the stimulated light emission, but the intensity of the laser light reflected by the imaging plate 21 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-rays incident on the imaging plate 21. 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 laser detection apparatus 40 also includes a condenser lens 51 and a light receiver (photo detector) 52. The condenser lens 51 is a part of the laser light emitted from the laser light source 41 and condenses the laser light reflected without passing through the polarization beam splitter 44 on the light receiving surface of the light receiver 52. The light receiver 52 is a light receiving element that outputs a light reception signal corresponding to the intensity of light collected on the light receiving surface. Accordingly, the light receiver 52 outputs a light reception signal corresponding to the intensity of the laser light emitted from the laser light source 41 to the laser driving circuit 77.

  Further, a light emitting element (LED) 53 is provided adjacent to the objective lens 46. The light emitting element 53 is controlled by the light emitting element driving circuit 84 to emit visible light and erase the diffraction ring imaged on the imaging plate 21. The light emitting element driving circuit 84 is controlled by the controller 91 and supplies the light emitting element 53 with a driving signal for generating visible light having a predetermined intensity.

  The light emitting element 55 is for detecting that the lower surface wall 64 of the X-ray diffraction measuring apparatus is in surface contact with the upper surface of the measurement object OB, and is driven by a light emitting element driving circuit 85 controlled by the controller 91. Then, light is applied to the lower surface wall 64 from an oblique direction. A through hole 64 b is provided at the irradiation position of the lower surface wall 64 by the light emitting element 55. Therefore, in a state where the lower surface wall 64 of the X-ray diffraction measurement device is in surface contact with the upper surface of the measurement object OB, the light emitted from the light emitting element 55 is irradiated to the measurement object OB through the through hole 64a. Then, the light reflected by the measurement object OB enters the case 60 again through the through hole 64a. The light receiver 56 is disposed at a position for receiving the light incident in the case 60. The light receiver 56 receives the light incident in the case 60 and supplies a light reception signal corresponding to the light reception intensity to the light emission signal detection circuit 86. Output. In the state where the inclined surface wall 67 of the X-ray diffraction measurement apparatus is in surface contact with the upper surface of the measurement object OB, the light emitted from the light emitting element 55 is reflected by the upper surface of the measurement object OB and is inside the case 60. Will never return. The light emission signal detection circuit 86 outputs a signal indicating light reception detection to the controller 91 when the intensity of the light reception signal input from the light receiver 56 is equal to or higher than the set intensity, and when the intensity is less than the set intensity. , Do not output the signal.

  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, ROM, RAM, a large capacity storage device, and the like, and executes various programs shown in FIGS. 3 to 7 stored in the large capacity storage device. . The input device 92 is connected to the controller 91 and is used by an operator to input various parameters, work instructions, and the like. The display device 93 visually notifies the operator of various setting situations, operating situations, measurement results, and the like. The high voltage power source 95 supplies a high voltage for X-ray emission to the X-ray emitter 10.

  Moreover, as shown in FIG. 11, the light shielding member 97 formed in the shape of a triangular prism is prepared as an accessory in the X-ray diffraction measuring apparatus described above. The light shielding member 97 has a pair of side surfaces intersecting at an inclination angle ψ with respect to the lower surface wall 64 of the inclined surface wall 67, and a notch 97 a is provided at the central portion in the width direction (left-right direction in the drawing) of the intersecting portion. ing. Then, when the X-ray diffractometer is placed on the upper surface of the measurement object OB and the X-ray is irradiated on the upper surface of the measurement object OB, the lower wall 64 or the inclined surface that is not in contact with the upper surface of the measurement object OB. Arranged below the face wall 67 to prevent the emission of X-rays to the outside.

  Below, the specific method of calculating | requiring the residual stress of the upper surface of the measuring object OB is demonstrated using the X-ray-diffraction measuring system containing the X-ray-diffraction measuring apparatus comprised as mentioned above. In the X-ray diffractometer configured as described above, in the storage state and the transport state, as shown in FIG. 12A, the support legs 68a and 68b are folded so as to be substantially parallel to the lower surface wall 64 and left and right side surfaces. It is stored in close contact with the walls 65 and 66.

  The X-ray diffraction measurement apparatus in such a state is carried with the handle 69 and placed on the upper surface of the measurement object OB. In this case, as shown in FIGS. 2 and 12B, the support legs 68a and 68b are rotated in the vertical direction with respect to the lower surface wall 64, the lower end portion is brought into close contact with the measurement object OB, and the inclined surface wall 67 is measured. The X-ray diffraction measurement device is maintained on the surface of the measurement object OB by being in close contact with the surface of the object OB. In this case, the X-ray diffraction measurement apparatus is set so that the measurement position of the measurement object OB comes to the position of the through hole 64a. In this state, the optical axis of the X-ray emitted from the X-ray emitter 10 and the normal line of the inclined surface wall 67 are set so as to form an inclination angle Ψ, and therefore the optical axis of the X-ray and the measurement object OB. The angle formed by the normal of the surface is set to the tilt angle Ψ. Thus, when the measurement object OB is irradiated with X-rays, diffraction X-rays are emitted from the measurement object OB, and a diffraction ring is formed on the imaging plate 21. Before the X-ray irradiation, as shown in FIGS. 2 and 12B, a light shielding member 97 is inserted between the upper surface and the lower surface wall 64 of the measurement object OB toward the inclined surface wall 67, and Prevent radiation of X-rays to the outside.

  Thereafter, the computer device 90 and the high voltage power source 95 are connected to the X-ray diffraction measurement device having the above-described configuration. And an operator inputs the material (for example, iron) of the measuring object OB using the input device 92, and instruct | indicates the measurement start of a residual stress. Thereby, the controller 91 starts execution of the diffraction ring imaging program shown in FIG.

  This diffraction ring imaging program is started in step S100 of FIG. 3, and the controller 91 controls the spindle motor control circuit 74 in step S102 to rotate the imaging plate 21 at a low speed and input an index signal from the encoder 37a. At that time, the rotation of the imaging plate 21 is stopped. Thereby, the rotation angle of the imaging plate 21 is set to 0 degree at the start of measurement. 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, starts the operation of the feed motor 32, and Thus, the operation of the feed motor 32 is stopped and the imaging plate 21 is moved to the diffraction ring imaging position.

  Next, the controller 91 starts the operation of the light reception signal detection circuit 86 in step S108, and controls the light emitting element driving circuit 85 to cause the light emitting element 55 to start light emission in step S110. In step S112, the controller 91 determines the presence or absence of a light reception detection signal from the light reception signal detection circuit 86. That is, it is determined whether or not the lower wall 64 is in surface contact with the upper surface of the measurement object OB. In this case, the light emitting element 55 begins to emit light to the outside of the case 60 through the through hole 64a, but the X-ray diffraction measurement device is placed so that the inclined surface wall 67 is in surface contact with the upper surface of the measurement object OB. Therefore, the light receiver 56 does not receive the reflected light from the measurement object OB of the emitted light. Therefore, the light reception signal detection circuit 86 does not output a light reception detection signal, and the controller 91 determines “No” in step S112, stops the operation of the light reception signal detection circuit 86 in step S114, and in step S116. The light emitting element driving circuit 85 is controlled to stop light emission by the light emitting element 55.

  After the processing in step S116, the controller 91 starts the operation of the sensor signal extraction circuit 76 in step S118, and controls the X-ray control circuit 71 in step S120 to emit X-rays to the X-ray emitter 10. Let it begin. 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 25. Next, the controller 91 inputs a light reception position signal from the sensor signal extraction circuit 76 in step S122, and calculates a distance L between the imaging plate 21 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 S124, 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 S126, the X-ray control circuit 71 is controlled to stop the X-ray irradiation to the measurement object OB.

  Next, in step S128, the controller 91 displays on the display device 93 that the set of X-ray diffraction measurement devices is inappropriate. In step S144, the execution of the diffraction ring imaging program ends. In this case, the operator resets the X-ray diffraction measurement apparatus again, and then instructs the start of measurement again using the input device 92. Since the time required from the above steps S120 to S126 is very short, the diffractive ring is not imaged on the imaging plate 21. Further, when the light receiving sensor 25 does not receive the X-ray reflected by the measurement object OB, it is displayed in step S128 that the set of the X-ray diffraction measurement device is inappropriate. Also in this case, the operator resets the X-ray diffraction measurement apparatus. Then, in response to the measurement start instruction, the processes in steps S102 to S124 described above are executed again, and the above processes are repeated until the distance L is within a predetermined reference range. However, when the processes of steps S102 to S124 are repeatedly executed as described above, the processes of steps S102 to S118 are substantially unnecessary.

  On the other hand, if the distance L is within the predetermined reference range during the determination process in step S124, the controller 91 determines “Yes” in step S124, proceeds to step S130, and performs the sensor signal extraction circuit. The operation of 76 is stopped. Then, the controller 91 starts time measurement in step S132, and determines in step S134 whether or not a predetermined set time for forming a diffraction ring by X-rays on the imaging plate 21 has elapsed. If the predetermined set time has not elapsed since the start of time measurement, it is determined as “No” in step S134 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. When a predetermined set time has elapsed from the start of time measurement, the controller 91 determines “Yes” in step S134, and controls the X-ray control circuit 71 in step S136 to control the X-ray emitted by the X-ray emitter 10. The irradiation of the line is stopped, and the execution of the diffraction ring imaging program is terminated in step S144.

  Thereby, in this state, the diffraction ring by the diffraction X-rays from the measurement object OB is imaged on the imaging plate 21.

  After the execution of the diffraction ring imaging program, the controller 91 starts execution of the diffraction ring reading program of FIGS. 4A and 4B. In this case, the controller 91 also starts executing the diffraction ring shape detection program of FIG. 5 in parallel with the execution of the diffraction ring reading program. Execution of the diffraction ring reading program is started in step S200 of FIG. 4A, and the controller 91 calculates a 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 21 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 of step S202, the controller 91 instructs the feed motor control circuit 73 to move the imaging plate 21 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 32 in cooperation with the position detection circuit 72 to move the imaging plate 21 to the reading start position. In a state where the imaging plate 21 is at the reading start position, the center of the objective lens 46, 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 sufficiently started from the inside by the processing described later, and the diffraction ring is reliably detected. The X-ray diffraction measurement apparatus at this time is in the state shown in FIG. 12C.

  Here, the position signal from the position detection circuit 72 indicating the movement distance x from the movement limit position of the moving stage 31 to the lower right direction in FIGS. 1 and 2, and the irradiation position of the laser light (objective) from the center of the imaging plate 21. The relationship with the distance to the lens 46 (the center position of the lens 46) (ie, the radius r of the irradiation position of the laser beam) will be described. In the state where the moving stage 31, that is, the imaging plate 21 is at the movement limit position, the distance from the center of the imaging plate 21 to the center position of the objective lens 46 is Rx as shown in FIG. In this case, the objective lens 46 is located in the upper left direction in FIGS. 1 and 2 from the center position of the imaging plate 21, and the distance Rx is measured in advance and stored in the controller 91. On the other hand, as shown in FIG. 8B, when the imaging plate 21 is moved from the movement limit position in the lower right direction in FIGS. 1 and 2 by a distance x, the radius r of the irradiation position of the laser beam becomes r = x + Rx. It is represented by 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 21 is moved to the reading start position, as shown in FIG. 8C, the irradiation position of the laser beam is on the inner side by a predetermined distance α from the diffraction ring reference radius R0. Therefore, the radius r in this case should be equal to the distance R0-α. Therefore, the distance x for moving the imaging plate 21 from the drive limit position in the lower right direction in FIGS. 1 and 2 is equal to x = R0−α−Rx. That is, in the process of moving to the reading start position in step S204, the table 20 is moved by the distance x (= R0−α−Rx) represented by the position signal output from the position detection circuit 72 as shown in FIGS. What is necessary is just to move to the lower right direction.

  Next, in step S206, the controller 91 instructs the spindle motor control circuit 74 to rotate the imaging plate 21 at a predetermined constant rotational speed. The spindle motor control circuit 74 controls the rotation of the spindle motor 37 so that the imaging plate 21 rotates at the specified constant rotation speed while calculating the rotation speed using the pulse signal from the encoder 37a. Therefore, the imaging plate 21 starts to rotate at the predetermined constant rotational speed. Next, in step S208, the controller 91 controls the laser drive circuit 77 to start irradiation of the imaging plate 21 with laser light from the laser light source 41.

  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 47 via the drive circuit 82 using the focus error signal from the amplifier circuit 78 and the focus error signal generating circuit 79. . As a result, the objective lens 46 is driven and controlled in the optical axis direction so that the focal point of the laser beam is aligned with the surface of the imaging plate 21. 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. Thereby, the rotation angle detection circuit 75 starts to output the rotation angle θp from the reference position of the spindle motor 37 (imaging plate 21) 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 21 in step S214. The feed motor control circuit 73 drives and controls the feed motor 32 to move the imaging plate 21 from the reading start position to the bearing portion 34 side (lower right direction in FIGS. 1 and 2) at a constant speed. As a result, the irradiation position of the laser beam starts to move relative to the imaging plate 21 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 light is relatively spirally rotated on the imaging plate 21 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 rotation (predetermined large value) by one rotation in the imaging plate 21. The radial direction number m represents a radial position from the inside to the outside of the imaging plate 21 and is a value that increases by “1” from “1” each time the imaging plate 21 rotates once. These circumferential direction number n and radial direction number m indicate a reading point P (n, m) that moves spirally on the imaging plate 21 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 37a. 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 21 from the rotation angle detection circuit 75 in step S220. .

  Then, in step S222, the controller 91 determines the difference between the current rotation angle θp and the rotation angle (n−1) · θo specified by the variable n (in this case, since n = 1, “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 determines “No” in step S222 and repeatedly executes 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” in step S222, 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) indicating the intensity of the photostimulated luminescence from the reading point P (n, m) of the imaging plate 21, 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 strength S (n, m) is greater than or equal to 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 radius r (n, m) are erased by detecting the peak position in the radial direction of the diffraction ring where the signal intensity S (n, m) is smaller than a predetermined reference value. 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 21 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 these 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 such circulation processing of steps S220 to S232, the controller 91 determines “Yes” in step S232, and in step S234, the diffractive ring shape 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 of 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 radial direction number m (= 1, 2, 3,...), Which is sequentially increased by “1”, and each radial direction number m by the processing in steps S218 to S238. Corresponding to a reading point P (n, m) designated by a circumferential direction number n (= 1 to N) corresponding to θ0, θo, 2 · θo (N−1) and 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. 4B. 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 in FIG. 5, 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. 4A. 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 intensity S (n, m) erased by the process of step S228 in FIG. 4A is not counted as the stored signal intensity 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. 10, 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 data representing the peak radii rp (n) at all the reading points P (n, m) related to the shape of these diffraction rings is obtained by using an X-ray diffraction measuring device with the inclined surface wall 67 on the upper surface of the measurement object OB. It is stored in the controller 91 as the first measurement value measured in the contact state.

  Now, let us return to the description of the diffraction ring reading program of FIGS. 4A and 4B. When the end command is output as described above, the controller 91 determines “Yes” in step S234 of FIG. 4A, and stops the focus servo control for the focus servo circuit 81 in step S240 of FIG. 4B. To stop the focus servo control. Next, the controller 91 controls the laser driving circuit 77 to stop the laser light irradiation by the laser light source 41 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 32 in step S246. As a result, the imaging plate 21 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 21 are continued as before.

  Next, the controller 91 executes the diffraction ring elimination program of 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 21 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 32 in cooperation with the position detection circuit 72 to move the imaging plate 21 to the erasure start position. In a state where the imaging plate 21 is at the erasing start position, the center of the visible light output from the light emitting element 53 is positioned at a position smaller than the calculated diffraction ring reference radius R0 by a predetermined distance γ. Specifically, when the distance from the center of the imaging plate 21 to the center of the light is Ry ′ in a state where the imaging plate 21 is at the drive limit position, the position output from the position detection circuit 72 is 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 light emitting element driving circuit 84 to start irradiating the imaging plate 21 with visible light by the light emitting element 53. Next, the controller 91 instructs the feed motor control circuit 73 to start and move the imaging plate 21 in step S406. The feed motor control circuit 73 drives and controls the feed motor 32 to move the imaging plate 21 from the erasing start position to the bearing portion 34 side (lower right direction in FIGS. 1 and 2) at a constant speed. As a result, visible light from the light emitting element 53 starts to move at a constant speed from the inside to the outside by a predetermined distance γ (γ> α) from the diffraction ring reference radius R0 while rotating in the imaging plate 21.

  After the process of step S406, the controller 91 inputs a position signal indicating the position of the imaging plate 21 from the position detection circuit 72 in step S408, and in step S410, the current position of the imaging plate 21 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 21 exceeds the erasure end position, the controller 91 determines “No” in step S410, and repeatedly executes the processes of steps S408 and S410. As a result, the rotating imaging plate 21 is irradiated with visible light from the light emitting element 53 from the inner side of the diffraction ring reference radius R0 by a predetermined distance γ to the outer side by a predetermined distance γ. The diffraction rings are gradually erased from the inside.

  When the current position of the imaging plate 21 exceeds the erasing end position, the controller 91 determines “Yes” in step S410, and stops the movement of the imaging plate 21 in the feed motor control circuit 73 in step S412. In step S414, the light emitting element driving circuit 84 is instructed to stop the irradiation of visible light by the light emitting element 53. Thereby, the feed motor control circuit 73 stops the movement of the imaging plate 21 by stopping the operation of the feed motor 32. The light emitting element driving circuit 84 stops the visible light irradiation by the light emitting element 53. 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 21 in step S418. In response to this instruction, the spindle motor control circuit 74 stops the operation of the spindle motor 37 and stops the rotation of the imaging plate 21. After the rotation of the imaging plate 21 is stopped, the controller 91 ends the execution of the diffraction ring elimination program in step S420.

  In such an X-ray diffraction measurement apparatus, the first measurement and the first measurement, which are diffraction ring formation and diffraction ring shape measurement, in a state where the inclined surface wall 67 is in surface contact with the upper surface of the measurement object OB. After the erasing of the diffraction ring in is completed, the second measurement is started. In this case, the operator holds the X-ray diffraction measurement apparatus on the upper surface of the measurement object OB while keeping the inclined surface wall 67 in contact with the upper surface of the measurement object OB. Rotate 90 degrees. Therefore, even in this state, as in the case of the first measurement, the angle formed by the optical axis of the X-ray and the normal line of the upper surface of the measurement object OB is set to the tilt angle Ψ. In this case, the measurement position of the measurement object OB, that is, the position of the upper surface of the measurement object OB irradiated with X-rays is the same as the first measurement position. Further, before the X-ray irradiation, as shown in FIGS. 2 and 12B, in order to prevent the X-ray from being emitted to the outside, a light shielding member 97 is provided between the upper surface and the lower surface wall 64 of the measurement object OB. Then, it is inserted toward the inclined surface wall 67.

  Then, as in the first measurement, the operator uses the input device 92 to instruct the start of residual stress measurement. In this case, the input of the material (for example, iron) of the measurement object OB is omitted. In response to the measurement start instruction, the controller 91 starts the execution of the diffraction ring imaging program shown in FIG. 3 again. Also in this case, since the X-ray diffraction measurement device is placed so that the inclined surface wall 67 is in surface contact with the upper surface of the measurement object OB, the light receiver 56 is the measurement object of the light emitted from the light emitting element 55. The light reflected by the OB is not received, and “No” is determined in step S112 in FIG. Therefore, also in the second measurement, the imaging plate 21 is diffracted by the X-ray irradiation to the measurement object OB by the processing of the above-described steps S102 to S136 as in the case of the first measurement. The ring is imaged. In this case, since the distance L between the imaging plate 21 and the measurement object OB is obtained by the first measurement, and the set of the X-ray diffraction measurement device is usually appropriate, step S118. , S122 to S130 may be omitted.

  After the execution of the diffraction ring imaging program, the controller 91 measures the shape of the imaged diffraction ring by executing the diffraction ring reading program of FIGS. 4A and 4B, as in the case of the first measurement. . As described above, when the calculation process of the distance L in step S122 is omitted when the second diffraction ring imaging program of FIG. 3 is executed, the diffraction ring of step S202 of the diffraction ring reading program of FIG. 4A is omitted. In the calculation of the reference radius, the distance L calculated by the process of step S122 of the first diffraction ring imaging program of FIG. 3 is used. In this case, the data representing the peak radii rp (n) at all the reading points P (n, m) related to the shape of the diffraction ring is obtained by using the X-ray diffraction measurement device and the inclined surface wall 67 of the measurement object OB. It is stored in the controller 91 as a second measurement value measured in a state of surface contact with the upper surface. Thereafter, as in the case of the first measurement, the diffraction ring imaged on the imaging plate 21 is erased by executing the diffraction ring elimination program of FIG.

  In such an X-ray diffraction measurement apparatus, the second measurement and the second measurement, which are diffraction ring formation and diffraction ring shape measurement, with the inclined surface wall 67 in surface contact with the upper surface of the measurement object OB. After the erasing of the diffraction ring in is completed, the third measurement is started. In this case, the operator folds the support legs 68a and 68b of the X-ray diffraction measurement apparatus so as to be parallel to the lower surface wall 64 and stores the support legs 68a and 68b in close contact with the left and right side walls 65 and 66. And while maintaining the measurement position of the measurement object OB, that is, the position of the upper surface of the measurement object OB irradiated with the X-rays, the X-ray diffraction measurement apparatus, The lower wall 64 is placed so as to be in surface contact with the upper surface of the measurement object OB. Therefore, in this case, since the optical axis of the X-ray is set parallel to the normal line of the lower surface wall 64, the X-ray light is different from the case of the first and second measurements. The axis is perpendicular to the surface of the measurement object OB. In this case, before the X-ray irradiation, as shown in FIG. 12D, the light shielding member 97 is attached to the upper surface of the measurement object OB and the inclined surface wall 67 in order to prevent the X-ray from being emitted to the outside. In between, it is inserted toward the lower wall 64.

  Then, similarly to the first and second measurements, the operator uses the input device 92 to instruct the start of residual stress measurement. In this case also, the input of the material (for example, iron) of the measurement object OB is omitted. In response to the measurement start instruction, the controller 91 starts the execution of the diffraction ring imaging program shown in FIG. 3 again. In this case, the X-ray diffractometer is placed so that the lower surface wall 64 is in surface contact with the upper surface of the measurement object OB. The reflected light from the object OB is received. Therefore, the controller 91 determines “Yes” in step S112 after the processing of steps S102 to S110 in FIG. 3, and proceeds to step S138 and subsequent steps.

  The controller 91 stops the operation of the light receiving signal detection circuit 86 by the processing of steps S138, S140, and S142 similar to steps S114, S116, and S120 described above, stops the light emission by the light emitting element 55, and emits X-rays. X-ray emission by the instrument 10 is started. Then, the controller 91 images the diffraction ring on the imaging plate 21 by irradiating the measurement object OB with X-rays by the processes in steps S132 to S136 described above, and ends the execution of the diffraction ring imaging program in step S144. . In this case, the distance L between the imaging plate 21 and the measurement object OB is obtained by the first measurement, and since the set of the X-ray diffraction measurement device is usually appropriate, the above-described step S118. , S122 to S130 are omitted.

  After the execution of the diffraction ring imaging program, the controller 91 measures the shape of the imaged diffraction ring by executing the diffraction ring reading program of FIGS. 4A and 4B, as in the case of the first measurement. . FIG. 12E shows a diffraction ring reading state of the X-ray diffraction measurement apparatus in the third measurement. In this case, in the calculation of the diffraction ring reference radius R0 in step S202 of the diffraction ring reading program in FIG. 4A, the distance calculated by the processing in step S122 of the diffraction ring imaging program in FIG. 3 in the first measurement. L is used. In this case, the data representing the peak radii rp (n) at all the reading points P (n, m) related to the shape of the diffraction ring is obtained by using the X-ray diffraction measurement device on the lower surface wall 64 of the measurement object OB. It is stored in the controller 91 as a third measurement value measured in a state of surface contact with the upper surface. Thereafter, as in the case of the first measurement, the diffraction ring imaged on the imaging plate 21 is erased by executing the diffraction ring elimination program of FIG.

Next, the stress calculation process will be described. The operator instructs the controller 91 to execute the stress calculation program using the input device 92. The stress calculation program is shown in FIG. 7, and the controller 91 starts execution of the stress calculation program in step S500. After starting the execution of the stress calculation program, the controller 91, in step S502, before the concrete calculation of the stress, the first to third measurement values detected from the first measurement to the third measurement. Using (the shape of the diffraction ring), the Bragg angle θ for each rotation angle α from the reference position of the diffraction ring (hereinafter referred to as the central angle α) is calculated for each diffraction ring. The Bragg angle θ is calculated by the following equation (1) using the diffractive ring radius R for each central angle α and the distance L calculated by the process of step S122 described above.

  Next, in step S504, the controller 91 uses the cos α method to perform residual residual stresses in the X, Y, and Z directions in the X, Y, and Z directions and the residual shear in the XY, XZ, and YZ planes. Calculate stress τxy, τxz, τyz.

  Here, a method of calculating the residual normal stresses σx, σy, σz and the residual shear stresses τxy, τxz, τyz will be described. Since this calculation method is a known method described in Japanese Patent Application Laid-Open No. 2011-27550 shown as Patent Document 2, the description will be briefly described with reference to the description of the same publication.

As shown in FIG. 13, X, Y, and Z coordinates with the origin at the X-ray irradiation position of the measurement object OB are assumed. The first measurement value described above is the shape data of the diffraction ring that belongs to the XZ plane and is measured in a state where the measurement object OB is irradiated with X-rays at an incident angle ψo (equal to the tilt angle ψ described above). The second measurement value described above is the shape data of the diffraction ring that belongs to the YZ plane and is measured in a state where the measurement object OB is irradiated with the X-ray at the incident angle Ψo, and the third measurement value is the XY plane. Is the shape data of the diffraction ring measured in a state in which the measurement object OB is irradiated with X-rays perpendicularly (equal to the Z axis). When the representative of the residual stress of the measuring object OB tensor sigma _ij, tensor sigma _ij is expressed by the following equation 2.

この場合、Ｅは縦弾性定数、ｖはポアソン比であり、いずれも回折弾性定数である。 Further, according to the basic formula of the area detector type triaxial stress assumption method, the strain ε _α in the direction of the rotation angle α (hereinafter referred to as the central angle α) from the reference position of the diffraction ring is expressed as the following equation (3): (See FIG. 13).

In this case, E is a longitudinal elastic constant, v is a Poisson's ratio, and both are diffraction elastic constants.

ここで、ηは中心角αにおけるブラッグ角θの補角［（π／２）−θ］であり、Ψｏは測定対象物ＯＢの上面の法線とＸ線の光軸とがなす角度（Ｘ線の入射角）であり、φｏは測定対象物ＯＢの上面（Ｘ−Ｙ平面）におけるＸ軸とＸ線の光軸とがなす角度である。 N ₁ ~n ₃ in the number 3 is the direction cosine of the strain epsilon _alpha for the measurement coordinate system, respectively represented by the following Expression 4.

Here, η is a complementary angle [(π / 2) −θ] of the Bragg angle θ at the central angle α, and Ψo is an angle (X) between the normal line of the upper surface of the measurement object OB and the optical axis of the X-ray. Is the angle formed by the X axis on the upper surface (XY plane) of the measurement object OB and the optical axis of the X-ray.

In the diffraction ring for an arbitrary angle φo (see FIG. 13), the strain ε _{α in} the direction of the central angle α, the strain ε _{π + α in} the direction different from the central angle α direction by π, the strain ε _{−α in the} central angle −α direction, and the center A strain ε _{π-α in a} direction different from the angle −α direction by π is assumed, and a ₁ (φo) and a ₂ (φo) expressed by the following equation 5 are assumed using these.

When the above formulas 3 and 4 are substituted into the above formula 5 and φo = 0, a ₁ (0) and a ₂ (0) are expressed by the following formula 6.

From Equation 6, a ₁ (0) and a ₂ (0) are linear with respect to cos α and sin α, respectively, and the slope of each straight line is expressed by Equation 7 below.

Here, when X-rays are irradiated perpendicularly to the upper surface of the measurement object OB, that is, when Ψo = 0, the following Expression 8 is derived from the Expression 7. This is because the residual shear stresses τxz and τyz are calculated by executing the following equation 8 using the Bragg angle θ for each central angle α obtained from the measurement result of the third diffraction ring, that is, the third measurement value. It means that you can ask.

Since the following equation 9 is derived from the first equation of the equation 7, and the residual shear stress τxz is obtained by the first equation of the equation 8, the residual vertical stress is obtained by executing the operation of the following equation 9. Stress σx−σz can be obtained. Since Ψo is the X-ray incident angle, the following formula 9 does not hold when Ψo = 0. In the following formula 9, a ₁ (0), that is, φo = 0. That is, the residual normal stress σx−σz can be obtained from the shape of the diffraction ring when X-rays are incident on the upper surface of the measurement object OB obliquely from the X direction. This means that the residual normal stress σx−σz is obtained by executing the following equation 9 using the Bragg angle θ for each central angle α obtained from the first measurement result of the diffraction ring, that is, the first measurement value. Means you can.

Further, by setting φo = 90 °, the following formula 10 corresponding to the formula 7 is established.

Since the following equation 11 is derived from the first equation of the equation 10 and the residual shear stress τyz is obtained by the second equation of the equation 8, the residual vertical stress is obtained by executing the operation of the following equation 11. The stress σy−σz can be obtained. In this case as well, since Ψo is an X-ray incident angle, the following formula 11 does not hold when Ψo = 0. In the following formula 11, a ₁ (90), that is, φo = 90 °. That is, the residual normal stress σy−σz can be obtained from the shape of the diffraction ring when X-rays are incident on the upper surface of the measurement object OB obliquely from the Y direction. This means that the residual normal stress σy−σz is obtained by executing the following equation 11 using the Bragg angle θ for each central angle α obtained from the measurement result of the second diffraction ring, that is, the second measurement value. Means you can.

Further, by transforming the second equation of Equation 7 and the second equation of Equation 10, the following Equation 12 is derived, and the residual shear stress τxz is obtained by the first equation of Equation 8. At the same time, since the residual shear stress τyz is obtained by the second equation of Equation 8, the residual shear stress τxy can be obtained by executing the calculation of Equation 12 below. In this case as well, since Ψo is the X-ray incident angle, the following equation 12 does not hold when Ψo = 0. In the first expression of the following formula 12, a ₂ (0), that is, φo = 0, and in the second expression, a ₂ (90), that is, φo = 90 °. That is, the residual shear stress τxy can be obtained from the shape of the diffraction ring when X-rays are incident on the upper surface of the measurement object OB obliquely from the X direction and the Y direction. This is because the execution of the following equation 12 using the Bragg angle θ for each central angle α obtained from the measurement results of the first and second diffraction rings, that is, the first and second measurement values, This means that the residual shear stress τxy can be obtained from the shape.

Further, by deforming Equation 3, the following Equations 13 and 14 are derived, and the residual normal stresses σx−σz and σy−σz are obtained by Equations 9 and 11, and the residual shear stresses τxz, τyz, Since τxy is obtained by the above equations 8 and 12, the residual normal stress σz can be obtained by executing the operations of the following equations 13 and 14. In this case, the following formulas 13 and 14 do not hold when Ψo = 0. Therefore, the residual shear stress τxy can be obtained from the shape of the diffraction ring when X-rays are incident on the upper surface of the measurement object OB obliquely from the X direction and the Y direction. Therefore, the residual normal stress σz is calculated for each central angle α to obtain an average value thereof. This is because the diffraction results are obtained by executing the following Expressions 13 and 14 using the Bragg angle θ for each central angle α obtained from the measurement results of the first and second diffraction rings, that is, the first and second measurement values. This means that the residual normal stress σz can be obtained from the shape of the ring.

  As described above, when the residual normal stress σz is obtained, the residual normal stresses σx−σz and σy−σz are obtained from the equations 9 and 11, so that the residual normal stresses σx and σy can be obtained. By executing the calculation as described above, the residual normal stresses σx, σy, σz and the residual shear stresses τxy, τxz, τyz are calculated.

  Returning to the description of the stress calculation program in FIG. 7 again, after calculating the residual stress in step S504, the controller 91 calculates the residual normal stress σx, σy, σz and residual shear stress τxy, calculated in step S506. τxz and τyz are displayed on the display device 93. And the controller 91 complete | finishes execution of this stress calculation program in step S508.

  As can be understood from the above description, in the above embodiment, the X-ray diffraction measurement device is accommodated in the case 60, so that the operator can easily carry the X-ray diffraction measurement device. . And after conveyance of this X-ray-diffraction measuring apparatus, it is perpendicular | vertical and mutually orthogonal to the surface of the measuring object OB by performing the 1st measurement and the 2nd measurement which made the inclined surface wall 67 surface-contact on the measuring object OB. The shape of the diffraction ring in two planes (XZ plane and YZ plane) when the surface of the measurement object OB is irradiated with X-rays at a predetermined angle with respect to the surface of the measurement object OB. It can be measured. Further, by performing the third measurement in which the lower surface wall 64 is brought into surface contact with the measurement object OB, the shape of the diffraction ring when the surface of the measurement object OB is irradiated with X-rays from the vertical direction can be measured. Then, by executing the stress calculation program of FIG. 7 based on the measurement values in these first to third measurements, residual stress (residual normal stress σx, σy, σz and residual shear stress τxy, τxz, τyz) can be obtained. As a result, according to the above embodiment, the X-ray direction can be easily changed at the measurement position while being easily transported to the measurement object OB, and the measurement object is large or fixed. Even so, an X-ray diffraction measuring apparatus capable of easily measuring the triaxial residual stress is realized.

  In the above embodiment, the case 60 is provided with support legs 68a and 68b for maintaining the inclined surface wall 67 in surface contact with the measurement object OB. Thereby, it is possible to reliably maintain a state in which the inclined surface wall 67 is brought into surface contact with the measurement object OB and the X-ray diffraction measurement device is placed on the measurement object OB with a simple configuration.

  In the above embodiment, the case 60 is provided with a handle 69 for conveyance. Thereby, since the X-ray diffraction measurement device can be transported by holding the handle, the transport of the X-ray diffraction measurement device becomes easier.

  Further, in the above embodiment, the reflected light of the light emitted through the through hole 64b of the lower surface wall 64 is detected by the light emitting element 55 and the light receiver 56, and the intensity of the reflected light is obtained by the process of step S112 in FIG. Based on this, the presence or absence of surface contact between the lower wall 64 and the surface of the measurement object OB is determined, and the processing of S118 to S130 is executed or not executed. Thereby, the processing content can be changed between when the lower surface wall 64 is in surface contact with the surface of the measurement object and when the inclined surface wall 67 is in surface contact with the surface of the measurement object OB. The efficiency of program processing can be improved.

  Furthermore, in carrying out the present invention, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the object of the present invention.

  In the explanation of the third measurement and the modification of the second measurement in the above embodiment, in the calculation of the diffraction ring reference radius R0 in step S202 of the diffraction ring reading program in FIG. The distance L calculated by the process of step S122 of the diffraction ring imaging program of FIG. 3 is used. Also, the calculated distance L is used in the calculation of the Bragg angle θ in step S502 of the stress calculation program of FIG. However, the distance L is set on the condition that there is no gap between the lower surface wall 64 and the inclined surface wall 67 and the measurement object OB in a state where the X-ray diffraction measurement device is placed on the upper surface of the measurement object OB. The diffraction ring reference radius R0 and the Bragg angle θ may be calculated using the distance L stored in advance. Further, even in the first measurement, when it is not necessary to determine whether the distance L in step S124 of the diffraction ring imaging program in FIG. 3 is within the set range, that is, the inclined surface wall 67 of the X-ray diffraction measurement apparatus is the measurement target. When the surface contact with the upper surface of the object OB can be confirmed by another method, or when confirmation is unnecessary, the process of step S124 is not necessary, and the distance L is also determined in the first measurement. Even if the measurement is not performed, the distance L stored in advance is used to calculate the diffraction ring reference radius R0 by the processing of step S202 of the diffraction ring reading program of FIG. 4A, and the steps of the stress calculation program of FIG. The Bragg angle θ may be calculated by the process of S502.

  Further, in the above embodiment, the light emitting element 55 that emits light in an oblique direction and the light receiver 56 that receives the reflected light from the upper surface of the measurement object OB are provided inside the lower surface wall 64, as shown in FIG. In step S112, the presence or absence of surface contact between the upper surface of the measurement object OB and the lower surface wall 64 is detected. However, instead of this, a light emitting element and a light receiver similar to the light emitting element 55 and the light receiver 56 are provided inside the inclined surface wall 67 to detect the presence or absence of surface contact between the upper surface of the measurement object OB and the inclined surface wall 67. You may make it do. In this case, in step S112, when it is detected that there is no surface contact between the upper surface of the measurement object OB and the inclined surface wall 67, it is determined that the upper surface of the measurement object OB and the lower surface wall 64 are in surface contact. That's fine.

  In addition to providing the light emitting element 55 and the light receiver 56 inside the lower surface wall 64 as in the above embodiment, a light emitting element and a light receiver similar to the light emitting element 55 and the light receiver 56 are provided inside the inclined surface wall 67. You may make it provide. In this case, in step S112, both the surface contact between the upper surface of the measurement object OB and the lower surface wall 64 and the surface contact between the upper surface of the measurement object OB and the inclined surface wall 67 are detected. According to this, it is possible to detect a state in which the upper surface of the measurement object OB is not in surface contact with both the lower surface wall 64 and the inclined surface wall 67, and the upper surface of the measurement object OB, the lower surface wall 64, and the inclined surface wall 67. It becomes possible to reliably detect contact with each surface. In this case, both the lower surface wall 64 and the inclined surface wall 67 can detect a state in which the surface of the measurement object OB is not in surface contact, and based on that, the X-ray emitted by the X-ray emitter 10 can be detected. The emission can be stopped.

  Further, in the above-described embodiment, the X-ray diffraction measurement apparatus is moved to the posture shown in FIG. However, as long as the same posture as that of FIG. 2 can be maintained, a support member having any structure may be provided. For example, a support leg that can be expanded and contracted in the vertical direction with respect to the lower surface wall 64 of the X-ray diffraction measurement apparatus is provided, and the support leg protrudes below the lower surface wall 64 to bring the X-ray diffraction measurement apparatus into the posture of FIG. You may make it maintain.

  Further, the folding support legs 68a and 68b are eliminated, and the triangular prism-shaped light shielding member 97 shown in FIG. Good. In this case, when the X-ray diffraction measurement apparatus is transported, it is necessary to transport a large light shielding member.

  In the above embodiment, the measurement object OB is large, and as shown in FIG. 2, the X-ray diffraction measurement device is placed on the measurement object OB and the residual stress of the measurement object OB is measured. In the above description, the imaging ring 21 is imaged with a diffraction ring by diffracted X-rays and the shape of the imaged diffraction ring is measured. However, this X-ray diffraction measurement apparatus can also be adapted to the measurement of residual stress when the measurement object OB is small. In this case, a fixing jig for fixing and supporting the X-ray diffraction measuring apparatus is prepared, the fixing jig is placed on the installation surface, and the left and right side walls 65 and 66 of the case 60 of the X-ray diffraction measuring apparatus are used as the fixing jig. By fixing, the X-ray diffraction measurement device is fixedly supported so that the inclined surface wall 67 is horizontal, or the X-ray diffraction measurement device is fixedly supported so that the lower wall 64 is horizontal.

  Then, on the installation surface, an elevator having an elevation stage for placing the measurement object OB is placed, and the measurement object OB is placed so that the inspection position of the small measurement object OB faces the position of the through hole 64a. After placing on the lifting stage, the lifting stage is raised to a height position where the measurement object OB contacts the lower surface wall 65 and the inclined surface wall 67. Thereafter, as in the above embodiment, the object OB is irradiated with X-rays to image the diffraction ring on the imaging plate 21, and the shape of the imaged diffraction ring is measured to calculate the residual stress. Even for the measurement object OB, the residual stress can be measured. However, in this case, the light emitting element 55 and the light receiver 56 of the above embodiment for detecting the presence or absence of surface contact with the upper surface and the lower surface wall 64 or the inclined surface wall 67 of the measurement object OB are provided in the vicinity of the through hole 64a. There is a need to.

  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 21 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 21 may be acquired and stored at predetermined time intervals. Good.

  In the above-described embodiment, the reading start position is determined using the light receiving position of the light receiving sensor 25, assuming an area where the radius of the imaged 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 21 may be irradiated with laser light. Similarly, visible light emitted from the light emitting element 53 may be always irradiated with visible light emitted from the light emitting element 53 in a certain region. For example, the entire region of the imaging plate 21 may be irradiated with visible light from the light emitting element 53. However, in this case, the measurement time is longer than in the above embodiment.

  In the above embodiment, the laser detection device 40 is controlled by focus servo. However, when the imaging plate 21 is rotated, the distance between the light receiving surface of the imaging plate 21 and the objective lens 46 is very small. If so, focus servo control is unnecessary.

  In the above-described embodiment, the laser beam applied to the imaging plate 21 is a laser beam having a constant intensity. Instead of this, a preset high level intensity and a preset low level laser beam 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 21 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 light intensity decreases due to the continued generation of light due to stimulated emission, but if configured as described above, the intensity of light generated by stimulated emission is reduced. By using this, the instantaneous value of the SUM signal can be acquired.

DESCRIPTION OF SYMBOLS 10 ... X-ray emitter, 20 ... Table, 21 ... Imaging plate, 25 ... Light receiving sensor, 30 ... Table drive mechanism, 31 ... Moving stage, 32 ... Feed motor, 33 ... Screw rod, 37 ... Spindle motor, 40 ... Laser Detection device, 41 ... laser light source, 46 ... objective lens, 50 ... light receiver, 53, 55 ... light emitting element, 56 ... light receiver, 60 ... case, 63 ... top wall, 64 ... bottom wall, 67 ... inclined wall, 64a ... through hole, 68a, 68b ... support leg, 69 ... handle, 90 ... computer device, 91 ... controller

Claims (7)

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 light receiver that receives the laser light, irradiates the light receiving surface of the imaging plate with light, and receives light emitted from the imaging plate by laser light irradiation. A laser detector that outputs a received light signal according to the received light intensity;
A rotation mechanism for rotating the table around the central axis of the through hole;
A moving mechanism for moving the table relative to the laser detection device in a direction parallel to the light receiving surface of the imaging plate;
An X-ray diffraction measurement apparatus comprising the X-ray emitter, the table, the imaging plate, the laser detection device, the rotation mechanism, and a case housing the movement mechanism,
The case has a flat first installation wall for placing the X-ray diffraction measurement device in surface contact with the measurement object, and an X-ray diffraction measurement device placed in surface contact with the measurement object. A flat second installation wall for placing the X-ray and the X-ray emitted from the X-ray emitter formed across the intersection of the first installation wall and the second installation wall An opening,
The X-ray diffracted from the measurement object when the measurement object is irradiated with the X-ray is formed at an angle formed by the normal line of the first installation wall and the optical axis of the X-ray emitted from the X-ray emitter. An X-ray diffraction measurement characterized in that it is set at a predetermined angle to be emitted and the optical axis of the X-ray emitted from the X-ray emitter is set parallel to the normal line of the second installation wall. apparatus. In the X-ray diffraction measuring apparatus according to claim 1 or 2,
The case has a lower surface wall perpendicular to the optical axis direction of the X-ray from which the X-ray is emitted from the X-ray emitter, and an inclined surface wall inclined with respect to the lower surface wall is formed at one end portion of the lower surface wall. The X-ray diffraction measurement apparatus is characterized in that the inclined wall is the first installation wall and the lower wall is the second installation wall. The X-ray diffraction measurement apparatus according to claim 2,
The X-ray diffraction measurement apparatus according to claim 1, wherein the case is formed in a rectangular parallelepiped shape, and the inclined surface wall is provided at a corner of one end portion of the lower surface wall in the moving direction of the table. In the X-ray-diffraction measuring apparatus as described in any one of Claims 1 thru | or 3,
An X-ray diffraction measurement apparatus, further comprising an erasing unit for erasing a diffraction ring recorded on the imaging plate in the case. In the X-ray-diffraction measuring apparatus as described in any one of Claims 1 thru | or 4,
An X-ray diffraction measurement apparatus, wherein the case is further provided with a support leg for maintaining the first installation wall in contact with the measurement object. In the X-ray-diffraction measuring apparatus as described in any one of Claims 1 thru | or 5,
An X-ray diffraction measurement apparatus, wherein the case is further provided with a handle for conveyance. The X-ray diffraction measurement apparatus according to claim 1, further comprising detecting reflected light of light emitted through the first installation wall or the second installation wall, and reflecting the detected light. An X-ray diffraction measuring apparatus comprising contact detection means for detecting the presence or absence of surface contact between the first installation wall or the second installation wall and the surface of the measurement object based on the intensity of light. .

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