JP5569510B2 - X-ray diffractometer - Google Patents

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.

  2. Description of the Related Art Conventionally, an X-ray diffraction measurement apparatus that measures the shape of a diffraction ring by X-ray diffraction in order to calculate a residual stress of a measurement object is known. In this type of X-ray diffraction measurement apparatus, there is an apparatus disclosed in Patent Document 1 below as an apparatus that can be downsized and that can shorten the X-ray irradiation time. This device irradiates a measurement object with X-rays at a predetermined angle, receives X-rays diffracted by the measurement object (hereinafter referred to as diffraction X-rays) with a photosensitive imaging plate, and forms them on the imaging plate. The shape of the circular X-ray diffraction image (hereinafter referred to as a diffraction ring) 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 the cos α method, a stress in an intersecting direction formed by a plane including the X-ray emission axis and the normal line of the measurement object and the plane of the measurement object (hereinafter referred to as vertical stress) can be calculated. Shear stress can also be calculated. This is suitable for evaluating the effect of shot peening. That is, shot peening increases the fracture strength of a metal by injecting a hard small sphere and hitting it on the surface of the metal, forming irregularities on the surface of the metal and generating residual compressive stress (belonging to normal stress). However, if the unevenness is sparse, even if the residual compressive stress is large, the shear stress remains at the portion where the unevenness is formed, and the fracture strength of the metal is insufficiently increased. When the unevenness is formed to such an extent that the individual unevenness cannot be identified, the shear stress becomes almost “0”, and the fracture strength of the metal is sufficiently increased. Therefore, after shot peening, it is possible to evaluate whether or not shot peening is sufficient by measuring the shear stress and confirming the value.

JP-A-2005-241308

  However, the material to be shot peened is often large, and it is difficult to carry the material to the place where the X-ray diffraction measurement apparatus is installed. Further, although the X-ray diffraction measurement apparatus disclosed in Patent Document 1 is small, it is not configured to be transported, and the X-ray diffraction measurement apparatus can be moved to the material that is the measurement object. It is also difficult to carry around. For this reason, it is the present condition that evaluation of whether shot peening is enough is not performed by this kind of X-ray-diffraction measuring apparatus. In addition to evaluating shot peening, it is difficult to carry an X-ray diffraction measurement device even if there is a need to measure the residual stress of a metal fixed to a building. It is the current situation that is not responding to.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to easily transport to a measurement object, irradiate the measurement object with X-rays, and diffract the X-rays at the measurement object. An object of the present invention is to provide an X-ray diffraction measuring apparatus capable of measuring the shape of a diffraction ring formed on the surface of an imaging plate. 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.

To achieve the above object, the present invention is the measuring object with X-ray emission device for emitting X rays toward a (OB) (10), the X-rays emitted from the X-ray emission device to a central A table (20) in which a through-hole to be passed is formed, and diffraction of X-rays that are attached to the table and pass through the X-ray emitted from the X-ray emitter at the center and diffracted by the measurement object An imaging plate (21) having a light receiving surface for receiving light and recording a diffraction ring as an image of diffracted light, a laser light source for emitting laser light, and a photodetector for receiving laser light, and imaging the laser light It irradiates the light receiving surface of the plate, the laser detector which receives the light emitted from the imaging plate by irradiation of a laser beam and outputs a light receiving signal corresponding to the received light intensity and (40), a solid table And a rotating mechanism having an output shaft which rotates about the center axis of the through hole formed to the table to the table, the through hole formed in the allowed by the table to pass through the X-ray emitted from the X-ray emission device A rotating mechanism (37) in which a through hole for guiding is formed in the output shaft, and a moving mechanism (31 to 33) for moving the table together with the rotating mechanism relative to the laser detection device in a direction parallel to the light receiving surface of the imaging plate. ) And a case (60) containing an X-ray emitter, a table, an imaging plate, a laser detection device, a rotation mechanism and a movement mechanism, and the case is formed in a rectangular parallelepiped shape. The lower surface wall (64) perpendicular to the optical axis direction of the X-ray emitted from the X-ray emitter, and the inclined surface inclined with respect to the lower surface wall at the corner of one end of the lower surface wall in the table moving direction (67), and the inclined surface wall has a flat plate shape so that the X-ray diffractometer is placed in surface contact with the object to be measured, and allows the X-rays emitted from the X-ray emitter to pass therethrough. An angle between the normal of the inclined wall and the optical axis of the X-ray emitted from the X-ray emitter is diffracted from the measurement object when the measurement object is irradiated with X-rays. That is, it is set to a predetermined angle at which X-rays are emitted.

In this case, the predetermined angle is, for example, Ru angle der in the range of 30 degrees to 45 degrees.

In the present invention configured as described above, the operator transports the X-ray diffraction measurement device to a place where the measurement object is located, and makes the inclined surface wall come into surface contact with the measurement object, so that the X-ray diffraction measurement is performed. Place the device on the measurement object. In this state, by irradiating the measurement object with X-rays through the opening provided on the inclined wall from the X-ray emission device, the optical axis of the X-rays emitted from the normal of the inclined wall and the X-ray emission device Is set to a predetermined angle at which X-rays diffracted from the measurement object are emitted, so the angle formed by the normal of the surface of the measurement object and the optical axis of the X-ray is also the predetermined angle. A diffraction ring is formed by X-rays diffracted from the measurement object and diffracted on the imaging plate. When the imaging plate is moved and rotated together with the table by operating the rotating mechanism and the moving mechanism with the laser detection device activated, the shape of the diffraction ring formed on the imaging plate can be measured with the laser beam. . Thus, according to the present invention, when carrying the X-ray diffractometer, it is only necessary to carry the case containing the X-ray emitter, the table, the imaging plate, the laser detector, the rotating mechanism and the moving mechanism. The X-ray diffraction measurement device can be easily transported. In addition, after the conveyance, the inclined surface wall is brought into surface contact with the measurement object, the X-ray diffraction measurement device is placed on the measurement object, and the X-ray emitter is operated to irradiate the measurement object with X-rays. Thus, a diffraction ring by diffraction X-rays is formed on the imaging plate, and the shape of the diffraction ring is measured by operating the laser detection device, the rotation mechanism, and the movement mechanism. And since the residual stress of the measurement object can be calculated based on the measurement result of the shape of the diffraction ring, it is easy to measure the residual stress of a large measurement object that is difficult to transport, such as the measurement object after shot peening. Become.

Another feature of the present invention is that the case is further provided with support legs (68a, 68b) for maintaining the inclined surface 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 inclined surface 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.

  Furthermore, another feature of the present invention resides in that a carrying handle (69) is further provided in the case. 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.

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 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 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 of the X-ray-diffraction measuring apparatus of FIG. It is a state diagram which shows the diffraction ring reading state of the X-ray-diffraction measuring apparatus of FIG. It is the schematic of the X-ray-diffraction measuring apparatus which concerns on the modification of this invention.

  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 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 the diffraction ring formed on the imaging plate 21, and a case 60 for housing these X-ray emitter 10, table 20, table drive mechanism 30 and laser detection device 40. I have. The case 60 also includes various circuits that are connected to the X-ray emitter 10, the table 20, the table driving mechanism 30, and the laser detection device 40 to control operation and input detection signals. In FIG. 1, various circuits indicated by a two-dot chain line shown outside the case 60 are accommodated in the 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. A circular through hole 67a is provided in the central portion of the inclined surface wall 67, and X-rays (X-rays emitted from the X-ray emitter 10) for forming a diffraction ring are allowed to pass through the through holes 67a. It is like that. The inclined surface wall 67 is brought into close contact with the surface (upper surface) of the measurement object OB, that is, brought into surface contact, and the measurement object OB is irradiated with X-rays to form a diffraction ring on the imaging plate 21.

  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 using the X-ray diffraction measuring apparatus, it is rotated and stretched 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 brought into close contact with the surface of the measurement object OB. Keep in contact. 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 direction of the exit port 11 of the X-ray emitter 10 is set so that the optical axis of the X-ray emitted from the X-ray emitter 10 and the normal line of the inclined surface wall 67 form a predetermined angle θ. This predetermined angle θ is an angle at which X-rays diffracted from the measurement object OB are emitted when the measurement object OB is irradiated with X-rays. For example, the predetermined angle θ is a predetermined angle within a range of 30 degrees to 45 degrees. is there. The optical axis of the X-ray is perpendicular to the upper surface wall 63 and the lower surface wall 64 of the case 60 and parallel to the front wall 61, the rear wall 62, and the left and right side walls 65, 66 of the case 60. .

  The X-ray control circuit 71 is controlled by a controller 91 that configures a computer device 90 to be described later, and a driving current supplied to the X-ray emitter 10 so that X-rays with a certain intensity are emitted from the X-ray emitter 10. And control the 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. Thus, when the imaging plate 21 is at the diffraction ring imaging position, the light receiving sensor 25 can directly receive the X-ray reflected by the measurement object OB. 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 the photodetector 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 reflected light of the laser light 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 condensing lens 48, a cylindrical lens 49, and a photodetector 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 photodetector 50 is composed of four divided light receiving elements composed of four light receiving elements of the same square shape divided by dividing lines, and the light incident on the light receiving areas A, B, C, and D arranged in the clockwise direction. A detection signal having a magnitude proportional to the intensity is output to the amplifier 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 photodetector 50 with the same amplification factor to generate light reception signals (a ′, b ′, c ′, d ′), Output to the focus error signal generation circuit 79 and the SUM signal generation circuit 80. In this embodiment, focus servo control based on the astigmatism method is used. The focus error signal generation circuit 79 generates a focus error signal by calculation using the amplified light reception signals (a ′, b ′, c ′, d ′). That is, the focus error signal generation circuit 79 calculates (a ′ + c ′) − (b ′ + d ′) and outputs the calculation result to the focus servo circuit 81 as a focus error signal. The focus error signal (a ′ + c ′) − (b ′ + d ′) represents the amount of deviation of the focal position of the laser beam from the surface of the imaging plate 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.

  Further, the laser detection device 40 includes a condenser lens 51 and a photodetector 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 photodetector 52. The photodetector 52 is a light receiving element that outputs a light receiving signal corresponding to the intensity of light collected on the light receiving surface. Therefore, the photodetector 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, an LED 53 is provided adjacent to the objective lens 46. The LED 53 is controlled by the LED drive circuit 84 to emit visible light and erase the diffraction ring imaged on the imaging plate 21. The LED driving circuit 84 is controlled by the controller 91 and supplies a driving signal for generating visible light having a predetermined intensity to the LED 53.

  The computer device 90 includes a controller 91, an input device 92, and a display device 93. The controller 91 is an electronic control device 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 6 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.

  The residual stress is obtained by measuring the diffraction ring of the iron material after performing shot peening, which is the measurement object OB, using the X-ray diffraction measurement system including the X-ray diffraction measurement apparatus configured as described above. A specific method will be described. In the X-ray diffractometer configured as described above, in the storage state and the transport state, as shown in FIG. 10A, the support legs 68a and 68b are folded so as to be parallel to the lower surface wall 64 and left and right side walls. 65 and 66 are stored in close contact with each other.

  The X-ray diffraction measurement apparatus in such a state is carried with the handle 69 and placed on the iron material that is the measurement object OB that has been shot peened. In this case, as shown in FIG. 2 and FIG. 10B, the support legs 68a and 68b are rotated in the vertical direction with respect to the lower surface wall 64, the lower end 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. Further, in this case, the X-ray diffraction measurement device is placed on the iron material as the measurement object OB so that the measurement position comes to the position of the through hole 67 a provided in the inclined surface wall 67. In this state, since 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 to form a predetermined angle θ, the optical axis of the X-ray and the measurement object The angle formed by the normal line of the OB surface is set to a predetermined angle θ. 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.

  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 sensor signal extraction circuit 76 in step S108. Next, in step S110, the controller 91 controls the X-ray control circuit 71 to cause the X-ray emitter 10 to start emitting X-rays. Thereby, X-rays are irradiated onto the measurement object OB, and the X-rays reflected on the surface of the measurement object OB are received by the light receiving sensor 25. Next, in step S112, the controller 91 inputs a light reception position signal from the sensor signal extraction circuit 76, 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 S114, the controller 91 determines whether or not the calculated distance L is within a predetermined reference range. If the distance L is not within the reference range, it is determined as “No”, and in step S116, the X-ray control circuit 71 is controlled to stop the irradiation of the measurement object OB with X-rays.

  In step S118, the controller 91 displays on the display device 93 that the set of X-ray diffraction measurement devices is inappropriate. In step S128, 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 S110 to S116 is very short, the diffractive ring is not imaged on the imaging plate 21. Further, even when the light receiving sensor 25 does not receive the X-ray reflected by the measurement object OB, it is displayed in step S118 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 S114 described above are performed again, and the processes are repeated until the distance L is within a predetermined reference range. However, when the processes of steps S102 to S114 are repeatedly executed as described above, the processes of steps S102 to S108 are substantially unnecessary.

  On the other hand, when the distance L is within the predetermined reference range at the time of the determination process in step S114, the controller 91 determines “Yes” in step S114, proceeds to step S120, and outputs a sensor signal extraction circuit. The operation of 76 is stopped. The controller 91 starts time measurement in step S122, and determines in step S124 whether or not a predetermined set time for forming a diffraction ring by X-rays on the imaging plate 21 has elapsed. If the predetermined set time has not elapsed since the start of time measurement, it is determined as “No” in step S124, and the determination process is continued. That is, the controller 91 stands by until a predetermined set time elapses from the start of time measurement. When a predetermined set time has elapsed from the start of time measurement, the controller 91 determines “Yes” in step S124, and controls the X-ray control circuit 71 in step S126 to control the X-ray emitted by the X-ray emitter 10. The irradiation of the line is stopped, and the execution of the diffraction ring imaging program is terminated in step S128.

  Thereby, in this state, 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. 10C.

  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. 7B, when the imaging plate 21 is moved by the distance x from the movement limit position in the lower right direction in FIGS. 1 and 2, 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. 7 (C), the irradiation position of the laser beam is inside the diffraction ring reference radius R0 by a predetermined distance α. 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 the radius r (n, m) are erased when the signal intensity S (n, m) smaller than a predetermined reference value is detected as the peak position of the diffraction X-ray intensity in the radial direction of the diffraction ring. This is because it is unnecessary.

  In step S230, the controller 91 adds “1” to the circumferential direction number n. In step S232, the controller 91 determines whether the variable n is larger than a value N representing the number of reading points P (n, m) per round, that is, whether the imaging plate 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. 9, all the radii r (n, m) at the circumferential position specified by the circumferential 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.

  Returning now 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. When the imaging plate 21 is at the erasing start position, the center of the visible light output from the LED 53 is located at a position smaller than the calculated diffraction ring reference radius R0 by a predetermined distance γ. Specifically, this position is output from the position detection circuit 72 when the distance from the center of the imaging plate 21 to the center of the visible light of the LED is Ry ′ in a state where the imaging plate 21 is at the drive limit position. This is the position where the position becomes R0-γ-Ry ′. Note that the predetermined distance γ is slightly larger than the predetermined distance α and is a position shifted with a margin from the radius of the imaged diffraction ring. Thereby, the imaged diffraction ring is surely erased by a process described later.

  Next, in step S404, the controller 91 controls the LED drive circuit 84 to start irradiating the imaging plate 21 with visible light by the LED 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 LED 53 starts moving 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, visible light from the LED 53 is irradiated from the diffraction ring reference radius R0 to the rotating imaging plate 21 from the inner side by a predetermined distance γ to the outer side by a predetermined distance γ, and thus the diffraction formed by the diffracted X-rays. The ring is 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 LED drive circuit 84 is instructed to stop the irradiation of visible light by the LED 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 LED drive circuit 84 stops the irradiation of visible light from the LED 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.

  After measuring the diffractive ring as described above, the controller 91 indicates the shape of the diffractive ring acquired by executing the diffractive ring shape detection program by executing a program (not shown) according to an instruction from the operator using the input device 92. Using the data, that is, using the peak radius rp (n) (n = 1 to N) and the rotation angle (n−1) θo (n = 1 to N) corresponding to the peak radius rp (n) (n = 1 to N), Residual compressive stress (normal stress) and shear stress at the measurement location are calculated, and the processing result by shot peening of the iron material is evaluated according to the calculated results. These residual compressive stress and shear stress are calculated using cos α, which is well known from the past, and shot peening is also evaluated based on the residual compressive stress and shear stress based on the calculation results. . In this case, if the residual compressive stress is large to some extent and the shear stress is a small value close to “0”, it is evaluated that shot peening is good.

  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 conveying this X-ray-diffraction measuring apparatus, the X-ray-diffraction measuring apparatus is mounted on the measuring object OB by making the inclined surface wall 67 which is an installation wall surface-contact on the measuring object OB. In this state, the angle formed by the normal line of the inclined surface wall 67 and the optical axis of the X-ray emitted from the X-ray emitter 10 is set to a predetermined angle at which the X-ray diffracted from the measurement object OB is emitted. Therefore, the angle formed by the normal of the surface of the measurement object OB and the optical axis of the X-ray is also the predetermined angle. Therefore, the measurement object OB is irradiated by irradiating the measurement object OB with the X-rays from the X-ray emitter 10 through the through hole 67a provided in the inclined surface wall 67, that is, by executing the diffraction ring imaging program of FIG. X-rays diffracted from the X-rays are emitted and diffracted by the X-rays diffracted on the imaging plate 21. As a result, the operator can perform imaging by simply placing the X-ray diffraction measuring device on the measurement object OB by bringing the inclined surface wall 67 as an installation wall into surface contact with the measurement object OB. A diffraction ring can be formed on the plate 21.

  After the diffraction ring is formed on the imaging plate 21, the shape of the diffraction ring is detected by executing the diffraction ring reading program of FIGS. 4A and 4B and the diffraction ring shape detection program of FIG. Since the residual stress of the measurement object OB can be calculated based on the detected shape of the diffraction ring, the measurement of the residual stress of the measurement object OB after the shot peening can be easily performed. Whether it was good or not can also be easily evaluated.

  Moreover, in the said embodiment, since the handle 69 for conveyance was provided in case 60, conveyance of an X-ray-diffraction measuring apparatus becomes easier. Furthermore, in the above embodiment, since the support legs 68a and 68b for maintaining the inclined surface wall 67, which is an installation wall, in contact with the measurement object OB are provided, the inclined surface wall 67 can be configured with a simple configuration. In close contact, that is, in surface contact with the measurement object OB, the state where the X-ray diffraction measurement device is placed on the measurement object OB can be reliably maintained.

  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 above-described embodiment, the folding support legs 68a and 68b, which are in close contact with the left and right side walls 65 and 66 of the case 60, are rotated 90 degrees to maintain the X-ray diffraction measurement apparatus in 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 moved back and forth 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 shown in FIG. You may make it maintain.

  Further, the folding support legs 68a and 68b are eliminated, and a triangular block having an angle equal to the angle at which the lower surface wall 64 and the inclined surface wall 67 of the case 60 intersect with each other is prepared. The X-ray diffraction measurement apparatus may be maintained in the same posture as in FIG. 2 by inserting it between the measurement object OB and the lower wall 64. In this case, when the X-ray diffraction measurement apparatus is transported, it is necessary to transport the block.

  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, as shown in FIG. 11, a fixing jig 101 for fixing and supporting the X-ray diffraction measuring apparatus is prepared, the fixing jig 101 is placed on the installation surface FL, and the right and left sides of the case 60 of the X-ray diffraction measuring apparatus are placed. By fixing the side walls 65 and 66 to the fixing jig 101, the X-ray diffraction measuring apparatus is fixedly supported so that the inclined surface wall 67 is horizontal.

  And on the installation surface FL, the elevator 102 provided with the raising / lowering stage 102a which mounts the measuring object OB is put. The elevating stage 102a can be moved up and down. Then, after placing the measurement object OB on the lift stage 102a so that the inspection position of the small measurement object OB is opposed to the position of the through hole 67a provided in the inclination surface wall 67, the measurement object OB is inclined wall. The raising / lowering stage 102a is raised to a height position in contact with 67 or a position close to the height position. After that, as in the above embodiment, the X-ray is irradiated onto the measurement object OB, the diffraction ring is imaged on the imaging plate 21, the shape of the captured diffraction ring is measured, and the residual stress is calculated. Even for the measurement object OB, the residual stress can be measured.

  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 LED 53 may be always irradiated with visible light emitted from the LED 53 in a certain region. For example, the entire region of the imaging plate 21 may be irradiated with visible light from the LED 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 intensity of the light decreases due to the continued generation of light due to the stimulated light emission. Thus, the instantaneous value of the SUM signal can be acquired.

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 ... photo detector, 60 ... case, 63 ... upper wall, 64 ... lower wall, 67 ... inclined wall, 67a ... through hole, 68a, 68b ... support leg, 69 ... Handle, 90 ... computer device, 91 ... controller

Claims (4)

An X-ray emitter that emits X-rays toward the measurement object;
A table in which a through hole that allows the X-ray emitted from the X-ray emitter to pass therethrough is formed in the center;
A diffracted light that is attached to the table and has a light receiving surface that allows X-rays emitted from the X-ray emitter to pass through at the center and receives diffracted light of X-rays diffracted by the measurement object. An imaging plate for recording a diffraction ring which is an image of
It has a laser light source that emits laser light and a photodetector that receives the laser light, and irradiates the light receiving surface of the imaging plate with the laser light and receives and emits the light emitted from the imaging plate by the laser light irradiation. A laser detection device that outputs a light reception signal corresponding to the intensity;
A rotation mechanism having an output shaft for fixing the table and rotating the table about a central axis of a through hole formed in the table , wherein the X-ray emitted from the X-ray emitter is passed through the rotation mechanism. A rotation mechanism in which a through hole led to a through hole formed in the table is formed in the output shaft ;
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 together with the rotation mechanism ;
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 is formed in a rectangular parallelepiped shape, the lower surface wall perpendicular to the optical axis direction of the X-rays emitted from the X-ray emitter, and the lower surface at the corner of one end portion of the lower surface wall in the moving direction of the table An inclined surface wall that is inclined with respect to the wall, and the inclined surface wall is in a plate shape for placing an X-ray diffraction measuring device in surface contact with an object to be measured, from the X-ray emitter Having an aperture through which the emitted X-rays pass;
X-rays diffracted from the measurement object are emitted when the measurement object is irradiated with X-rays at an angle formed by the normal of the inclined surface wall and the optical axis of the X-ray emitted from the X-ray emitter. An X-ray diffraction measurement apparatus characterized by being set to a predetermined angle. The X-ray diffraction measurement apparatus according to claim 1,
The X-ray diffraction measurement apparatus, wherein the predetermined angle is an angle within a range of 30 degrees to 45 degrees. In the X-ray diffraction measuring apparatus according to claim 1 or 2 ,
An X-ray diffraction measuring apparatus, wherein the case is further provided with a support leg for maintaining the inclined surface wall in surface contact with the measurement object. In the X-ray-diffraction measuring apparatus as described in any one of Claims 1 thru | or 3 ,
An X-ray diffraction measurement apparatus, wherein the case is further provided with a handle for conveyance.

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