JP4887517B2 - Surface inspection apparatus and centering adjustment method for inspection head - Google Patents

Description

  The present invention relates to an apparatus for inspecting the surface of an inspection object by irradiating the inspection object with inspection light from an inspection head.

As an apparatus for inspecting the inner peripheral surface of a cylindrical inspection object, an inspection head is inserted into the inspection object by rotating the axial inspection head around its axis and inserting it into the inspection object. The inspection object is irradiated with laser light as inspection light from the outer periphery, and the inner peripheral surface of the inspection object is sequentially scanned from one end to the other end in the axial direction, and the reflected light from the inspection object corresponding to the scanning is scanned. A surface inspection apparatus that receives light through an inspection head and determines the state of an inner peripheral surface of an object to be inspected, such as the presence or absence of a defect, based on the amount of reflected light received (see, for example, Patent Document 1). ).
JP-A-11-281582

  In the above-described conventional apparatus, it is necessary to perform centering adjustment so that the center position of the inner peripheral surface of the inspection target and the axis of the inspection head coincide each time the inspection target or the inspection target portion of the inspection target changes. is there. When the work is entrusted to manual work such as a dial gauge, the work burden is large. Even when using a jig to improve work efficiency, a jig is required for each object to be inspected, resulting in a large equipment burden.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface inspection apparatus and a centering adjustment method that can reduce the burden required for centering adjustment of an inspection head.

  The surface inspection apparatus (1) of the present invention irradiates inspection light from the outer periphery of an inspection head (16) extending in an axial direction toward the inner peripheral surface (100a) of the inspection object (100), Detection means (5) for receiving reflected light from the inspection object with respect to irradiation through the inspection head and outputting a signal corresponding to the amount of the reflected light, and linear drive for moving the inspection head in the axial direction Means (30) and rotation drive means (40) for rotating the inspection head around its axis (AX), the inspection head irradiates inspection light in the axial direction from the tip, and On the other hand, in the surface inspection apparatus configured to receive the reflected light returning in the axial direction, the inspection head has a first axial direction (X-axis direction) orthogonal to the axial direction with respect to the inspection object. And second axis Head position adjusting means (7) that moves relatively in the direction (Y-axis direction) and the first axial direction and the second axial direction, respectively, are ejected in the axial direction from the tip of the inspection head. Scanning control means (60, S1, S4) for controlling the operation of the head position adjusting means so that the inspection object is scanned in a range including two points on the contour of the inner peripheral surface by inspection light; Calculation means (60,) for calculating a center position (C) in the radial direction of the inner peripheral surface of the inspection object based on signals output from the detection means during scanning in the first and second axis directions. S3, S5, S6) and positioning control means (60, S7) for controlling the operation of the head position adjusting means so that the axis of the inspection head coincides with the calculated center position. Issues Resolve.

  Further, the inspection head centering adjustment method of the present invention irradiates inspection light from the outer periphery of the inspection head (16) extending in the axial direction toward the inner peripheral surface (100a) of the inspection object (100), and Detection means (5) for receiving reflected light from the inspection object in response to irradiation of inspection light through the inspection head and outputting a signal corresponding to the amount of the reflected light; and moving the inspection head in the axial direction Linear driving means (30) for rotating, and rotation driving means (40) for rotating the inspection head around its axis (AX), the inspection head irradiates inspection light in the axial direction from the tip, In the surface inspection apparatus configured to receive the reflected light returning in the axial direction with respect to the irradiation, the axis of the inspection head is defined as the center position (C) in the radial direction of the inner peripheral surface of the inspection object. Match An inspection head centering adjustment method for the inspection head, wherein the inspection head is perpendicular to the axial direction with respect to the object to be inspected in a state where inspection light is emitted from the inspection head in the axial direction. A first scanning step (S1) of scanning the inspection object with the inspection light in a range including two points on the contour of the inner peripheral surface by relatively moving in the axial direction (X-axis direction). And a second axis that is perpendicular to the axial direction and different from the first axial direction with respect to the inspection object in a state in which inspection light is emitted from the inspection head in the axial direction. A second scanning step (S4) in which the inspection object is scanned with the inspection light in a range including two points on the contour of the inner peripheral surface by relatively moving in the direction (Y-axis direction). , From the detection means in the first and second scanning steps, respectively. A calculation step (S3, S5, S6) for calculating a center position in the radial direction of the inner peripheral surface of the object to be inspected based on the output signal, and an axis of the inspection head at the calculated center position. By providing a positioning step (S7) for relatively moving the inspection head and the object to be inspected so as to match, the above-described problems are solved.

  When the inspection head is relatively moved in the first axial direction and the second axial direction and the inspection object is scanned with the inspection light, the reflected light is reflected if the inspection light passes through the hole of the inspection object. It does not return, or even if it returns, the amount of light is small. On the other hand, when the inspection light is incident on the end surface of the inspection object, the reflected light returns to the inspection head with a sufficient amount of light. Therefore, by referring to the output signal of the detecting means during scanning, it is possible to determine the positions where the inspection light passes through the two points on the contour of the inner peripheral surface. The center position of the inner peripheral surface is a vertical bisector of a line segment (string) connecting two points on the inner peripheral surface contour in the first axial direction and the inner peripheral surface contour in the second axial direction. Of the inner peripheral surface determined by the respective scans in the first axial direction and the second axial direction. Calculation can be performed using the geometrical relationship from the positions of the upper two points (four points in total). Then, the axis of the inspection head can be made to coincide with the center position of the inspection object by moving the inspection head relative to the inspection object so that the inspection head matches the calculated center position.

  According to the surface inspection apparatus of the present invention, the operation of the head position adjusting unit is controlled by the scanning control unit to scan the inspection object in the first and second axial directions, and the output signal of the detecting unit during the scanning Therefore, the center position of the inner peripheral surface of the object to be inspected can be calculated in accordance with the above-described geometrical relationship. The centering adjustment can be completed by controlling the operation of the head position adjusting means so that the axis of the inspection head coincides with the center position by the positioning control means. Further, according to the centering adjustment method of the present invention, the object to be inspected is scanned in the first and second axial directions in the first and second scanning steps. The center position of the inner peripheral surface of the inspection object can be calculated based on the output signal of the detection means. Then, in the positioning step, the centering adjustment can be completed by relatively moving the inspection head and the inspection object so that the axis of the inspection head coincides with the center position.

  In one form of the surface inspection apparatus of this invention, the said calculating means (60) is the said internal peripheral surface in the said 1st axial direction based on the output signal of the said detection means corresponding to the scanning regarding the said 1st axial direction. Based on the output signal of the first coordinate determining means (S3) for determining the coordinates (Xa, Xb) of the two points on the contour of the second and the detection means corresponding to the scanning in the second axial direction. A second coordinate discriminating means (S5) for discriminating the coordinates (Ya, Yb) of the two points on the contour of the inner peripheral surface in the axial direction, and the coordinates of the two points discriminated by the first coordinate discriminating means. The coordinate (Xc) of the intermediate point in the first axial direction and the coordinate (Yc) of the intermediate point in the second axial direction determined by the second coordinate determining means are the coordinates of the center position. And center coordinate calculation means (S6) It may be. According to this aspect, the coordinate in the same direction of the intermediate point of the two coordinate points determined with respect to the first axial direction and the coordinate in the same direction of the intermediate point of the two coordinate points determined with respect to the second axial direction Coordinates relating to the first and second axial directions of the center position can be obtained.

  In one form of the surface inspection apparatus of this invention, the signal corresponding to the reflected light more than predetermined light quantity is output from the said detection means at the time of the scan regarding at least any one direction among the said 1st and 2nd axial directions. If not, an error processing means (60, S2, S8) for outputting an error signal indicating that the axis of the inspection head and the axis of the inner peripheral surface of the inspection object are not parallel to each other is further provided. Good. If the axis of the inspection head and the axis of the inner peripheral surface of the inspection object are not parallel, only the reflected light of less than a predetermined amount of light can be detected or the reflected light cannot be detected even when the inspection object is scanned. Therefore, if an error signal is output in such a case, it becomes possible to prompt confirmation of the parallel state or to correct it.

  In one form of the surface inspection apparatus of this invention, the said detection means, the said linear drive means, and the said rotation drive means are arrange | positioned on the common base (31), The said head position adjustment means makes the said base the said 1st. It may be moved in at least one of the first and second axial directions. In this case, since the detection means, the linear drive means and the rotation drive means on the base can be moved integrally, without changing the positional relationship of these linear drive means and rotation drive means with respect to the axis of the inspection head, The position can be adjusted by moving the inspection head in at least one axial direction with respect to the inspection object.

  In the centering adjustment method of the present invention, a form similar to the form of the surface inspection apparatus described above may be adopted. That is, in the centering adjustment method of the present invention, the calculation step is performed on the contour of the inner peripheral surface in the first axial direction based on an output signal of the detection unit corresponding to scanning in the first axial direction. A first coordinate determining step (S3) for determining the coordinates (Xa, Xb) of the two points, and the second axial direction based on the output signal of the detecting means corresponding to the scanning in the second axial direction In the second coordinate discrimination step (S5) for discriminating the coordinates (Ya, Yb) of the two points on the contour of the inner peripheral surface, and the intermediate point of the two coordinates discriminated in the first coordinate discrimination step The coordinate (Yc) in the second axial direction of the intermediate point between the coordinates (Xc) in the first axial direction and the coordinates of the two points determined in the second coordinate determining step is calculated as the coordinate of the center position. And a center coordinate calculation step (S6). . Further, when a signal corresponding to reflected light of a predetermined light amount or more is not output from the detection means during scanning in at least one of the first and second axial directions, the axis of the inspection head and the An error processing step (S2, S8) for outputting an error signal indicating that the axis of the inner peripheral surface of the inspection object is in a non-parallel state may be further provided. In each of the first scanning step, the second scanning step, and the positioning step, the detection unit, the linear driving unit, and the rotational driving unit are at least one of the first and second axial directions. It may be moved integrally in either direction.

  In addition, in the above description, in order to make an understanding of this invention easy, the reference sign of the accompanying drawing was attached in parenthesis, but this invention is not limited to the form of illustration by it.

  As described above, according to the surface inspection apparatus and the centering adjustment method of the present invention, the inspection object is irradiated with the inspection light irradiated in the axial direction from the tip of the inspection head in the first axial direction and the second axial direction. Scan in the axial direction, calculate the center position of the inner peripheral surface of the inspection object based on the signal corresponding to the amount of reflected light output from the detection means along with the scan, and the inspection head at the calculated center position Since the inspection head is moved relative to the object to be inspected so that their axes coincide with each other, the burden required for centering adjustment of the inspection head can be reduced and the efficiency of inspection work can be improved.

  FIG. 1 shows a schematic configuration of a surface inspection apparatus according to an embodiment of the present invention. The surface inspection apparatus 1 is an apparatus suitable for inspecting an inner peripheral surface 100a provided on a workpiece 100 as an object to be inspected, and includes an inspection mechanism 2 for executing inspection, operation control of the inspection mechanism 2, and an inspection mechanism. And a control unit 3 for executing processing of the measurement result by 2 and the like. The workpiece 100 has a cylindrical shape with a constant inner diameter and outer diameter, and is, for example, a cylinder liner that is fitted into a cylinder block of an internal combustion engine. The workpiece 100 is set at a position facing the surface inspection device 1 by a workpiece support device (not shown). The inspection mechanism 2 projects inspection light onto the workpiece 100 and detects the detection unit 5 as detection means for receiving reflected light from the workpiece 100, and for giving a predetermined operation to the detection unit 5. And a drive unit 6.

  The detection unit 5 receives a laser diode (hereinafter referred to as LD) 11 as a light source of inspection light and reflected light from the workpiece 100, and according to the amount of reflected light per unit time (reflected light intensity). A photodetector (hereinafter referred to as PD) 12 that outputs a current or voltage signal, a light projecting fiber 13 that guides inspection light emitted from the LD 11 toward the workpiece 100, and reflected light from the workpiece 100 to the PD 12. It includes a light receiving fiber 14 for guiding, a holding cylinder 15 that holds the fibers 13 and 14 in a bundled state, and a hollow shaft-like inspection head 16 that is provided coaxially outside the holding cylinder 15. . At the tip of the holding cylinder 15, the inspection light guided through the light projecting fiber 13 is in the direction of the axis AX of the inspection head 16 (corresponding to the Z-axis direction in FIG. 1, which is hereinafter referred to as the axial direction). A lens 17 is provided that collects the reflected light that is emitted in the form of a beam along the axial direction of the inspection head 16 and that travels in the direction opposite to the inspection light along the axial direction of the inspection head 16. A mirror 18 as an optical path changing means is fixed to the tip portion (right end portion in FIG. 1) of the inspection head 16, and a light transmission window 16 a is provided on the outer periphery of the inspection head 16 so as to face the mirror 18. ing. The mirror 18 changes the optical path of the inspection light emitted from the lens 17 toward the light transmission window 16 a, and advances the optical path of the reflected light that has entered the inspection head 16 from the light transmission window 16 a toward the lens 17. Change direction.

  As shown in FIGS. 2 and 3, the inspection head 16 includes a cylindrical head main body 20 and a mirror holding cylinder 21 attached to the tip of the main body 20. The mirror holding cylinder 21 is screwed into a male screw portion 20 a at the tip of the main body 20, whereby the mirror holding cylinder 21 is detachable from the main body 20. The translucent window 16 a described above is provided on the outer periphery of the mirror holding cylinder 21, and the mirror 18 is detachably attached to the inside of the mirror holding cylinder 21. The front end surface of the mirror holding cylinder 21 is provided with a hole 21a for emitting the inspection light B1 from the inspection head 16 in the axial direction and allowing the reflected light B2 from the axial direction to enter the inspection head 16. When the inspection light B1 is emitted from the punched hole 21a, the mirror holding cylinder 21 is attached to the head body 20 with the mirror 18 removed.

  Returning to FIG. 1, the description will be continued. The drive unit 6 includes a linear drive mechanism 30, a rotation drive mechanism 40, and a focus adjustment mechanism 50. The linear drive mechanism 30 is provided as a linear drive means for moving the inspection head 16 in the axial direction. In order to realize such a function, the linear drive mechanism 30 includes a base 31, a pair of rails 32 fixed to the base 31, and a slider 33 that can move in the axial direction of the inspection head 16 along the rails 32. Further, a feed screw 34 disposed in parallel to the axis AX of the inspection head 16 and a motor 35 that rotationally drives the feed screw 34 are provided on the side of the slider 33. The slider 33 functions as a means for supporting the entire detection unit 5. That is, the LD 11 and PD 12 are fixed to the slider 33, the inspection head 16 is attached to the slider 33 via the rotation drive mechanism 40, and the holding cylinder 15 is attached to the slider 33 via the focus adjustment mechanism 50. Further, a nut 36 is fixed to the slider 33, and a feed screw 34 is screwed into the nut 36. Therefore, when the feed screw 34 is rotationally driven by the electric motor 35, the slider 33 moves along the rail 32 in the axial direction of the inspection head 16, and accordingly, the entire detection unit 5 supported by the slider 33 is moved. It moves in the axial direction of the inspection head 16. By driving the detection unit 5 using the linear drive mechanism 30, the irradiation position (scanning position) of the inspection light on the inner peripheral surface 100 a of the workpiece 100 can be changed with respect to the axial direction of the inspection head 16. A wall 31a is provided at the front end (right end in FIG. 1) of the base 31, and a through hole 31b coaxial with the inspection head 16 is provided in the wall 31a. The through hole 31 b has an inner diameter through which the inspection head 16 can pass, and the inspection head 16 passes through the through hole 31 b and is drawn out into the workpiece 100.

  The rotation drive mechanism 40 is provided as a rotation drive unit that rotates the inspection head 16 around the axis AX. In order to realize such a function, the rotation drive mechanism 40 includes a bearing (not shown) that supports the inspection head 16 so as to be rotatable around the axis AX, an electric motor 41 as a rotation drive source, and the electric motor 41. And a transmission mechanism 42 that transmits the rotation of the rotation to the inspection head 16. As the transmission mechanism 42, a known rotation transmission mechanism such as a belt transmission device or a gear train may be used. By transmitting the rotation of the electric motor 41 to the inspection head 16 via the transmission mechanism 42, the inspection head 16 rotates around the axis AX with the mirror 18 fixed therein. By rotating the inspection head 16 using the rotation drive mechanism 40, the irradiation position of the inspection light on the inner peripheral surface 100a of the workpiece 100 can be changed in the circumferential direction of the workpiece 100. Then, by combining the movement of the inspection head 16 in the axial direction and the rotation around the axis AX, the inner peripheral surface 100a of the workpiece 100 can be scanned with the inspection light over the entire surface. Note that the holding cylinder 15 does not rotate when the inspection head 16 rotates. Further, the rotary drive mechanism 40 is provided with a rotary encoder 43 that outputs a pulse signal each time the inspection head 16 rotates by a predetermined unit angle. The number of pulse signals output from the rotary encoder 43 correlates with the rotation amount (rotation angle) of the inspection head 16, and the period of the pulse signals correlates with the rotation speed of the inspection head 16.

  The focus adjustment mechanism 50 is provided as a focus adjustment unit that drives the holding cylinder 15 in the direction of the axis AX so that the inspection light is focused on the inner peripheral surface 100a of the workpiece 100. In order to realize the function, the focus adjustment mechanism 50 is disposed between the support plate 51 fixed to the base end portion of the holding cylinder 15 and the slider 33 and the support plate 51 of the linear drive mechanism 30. Rail 52 that guides the inspection head 16 in the axial direction, a feed screw 53 that is arranged parallel to the axis AX of the inspection head 16 and screwed into the support plate 51, and an electric motor 54 that rotationally drives the feed screw 53. It has. By rotating the feed screw 53 with the electric motor 54, the support plate 51 moves along the rail 52, and the holding cylinder 15 moves in the axial direction of the inspection head 16. Thereby, the length of the optical path from the lens 17 through the mirror 18 to the inner peripheral surface 100a can be adjusted so that the inspection light is focused on the inner peripheral surface 100a of the workpiece 100.

  Further, the surface inspection apparatus 1 is provided with a head position adjusting mechanism 7 as a head position adjusting means. The head position adjusting mechanism 7 includes an X-axis direction (direction perpendicular to the paper surface of FIG. 1) as the first axial direction perpendicular to the axial direction (Z-axis direction) of the inspection head 16 and the Z thereof. Driving is performed in the Y-axis direction as a second axial direction orthogonal to both the axial direction and the X-axis direction. The head position adjusting mechanism 7 connects, for example, a commercially available XY stage apparatus that positions and drives the stage in two orthogonal axes to the base 31 so that the moving direction of the stage coincides with the X-axis direction and the Y-axis direction. This can be realized. When the base 31 is placed on a horizontal plane, a so-called XZ stage apparatus that combines an X table that drives the stage in one axial direction in the horizontal plane and a Z table that drives the stage in the vertical direction is used as a head position. What is necessary is just to utilize as the adjustment mechanism 7. FIG.

  Next, the control unit 3 will be described. The control unit 3 includes an arithmetic processing unit 60 as a computer unit that executes inspection process management by the surface inspection apparatus 1, processing of measurement results of the detection unit 5, etc., and each unit of the detection unit 5 in accordance with instructions from the arithmetic processing unit 60. An operation control unit 61 for controlling the operation of the signal processing unit, a signal processing unit 62 for executing a predetermined process on the output signal of the PD 12, an input unit 63 for a user to input an instruction to the arithmetic processing unit 60, An output unit 64 for presenting test results and the like processed by the arithmetic processing unit 60 to the user, a computer program to be executed by the arithmetic processing unit 60, and a storage unit 65 for storing measured data and the like. ing. The arithmetic processing unit 60, the input unit 63, the output unit 64, and the storage unit 65 can be configured using a general-purpose computer device such as a personal computer. In this case, the input unit 63 is provided with input devices such as a keyboard and a mouse, and the output unit 64 is provided with a monitor device. An output device such as a printer may be added to the output unit 64. The storage unit 65 is a hard disk storage device or a storage device such as a semiconductor storage element capable of storing data. The operation control unit 61 and the signal processing unit 62 may be realized by a hardware control circuit or may be realized by a computer unit.

  When inspecting the surface of the inner peripheral surface 100a of the workpiece 100, each of the arithmetic processing unit 60, the operation control unit 61, and the signal processing unit 62 operates as follows. In this case, the axis of the inner peripheral surface 100a of the workpiece 100 is arranged coaxially with the axis AX of the inspection head 16. The centering adjustment between the workpiece 100 and the inspection head 16 will be described later. In starting the inspection, the arithmetic processing unit 60 instructs the operation control unit 61 to start an operation necessary for inspecting the inner peripheral surface 100 a of the workpiece 100 in accordance with an instruction from the input unit 63. Upon receiving the instruction, the operation control unit 61 causes the LD 11 to emit light with a predetermined intensity, and the operations of the motors 35 and 41 so that the inspection head 16 moves in the axial direction and rotates around the axis AX at a constant speed. To control. Further, the operation control unit 61 controls the operation of the motor 54 so that the inspection light is focused on the inner peripheral surface 100a as the surface to be inspected. By such operation control, the inner peripheral surface 100a is scanned by inspection light from one end to the other end. The driving of the inspection head 16 in the axial direction may be a feeding operation at a constant speed, or an intermittent feeding operation that moves by a predetermined pitch every time the inspection head 16 rotates.

  The output signal of the PD 12 is sequentially guided to the signal processing unit 62 in conjunction with the above-described scanning of the inner peripheral surface 100a. The signal processing unit 62 performs analog signal processing necessary for processing the output signal of the PD 12 by the arithmetic processing unit 60, and further performs A / D conversion on the analog signal after the processing with a predetermined number of bits, The obtained digital signal is output to the arithmetic processing unit 60 as a reflected light signal. The signal processing executed by the arithmetic processing unit 60 includes various processes such as a process of nonlinearly amplifying the output signal so as to enlarge the brightness difference of the reflected light detected by the PD 12 and a process of removing a noise component from the output signal. May be used as appropriate. Fast Fourier transform processing, inverse Fourier transform processing, and the like can be appropriately combined. The A / D conversion by the signal processing unit 62 is performed using a pulse train output from the rotary encoder 43 as a sampling clock signal. As a result, a digital signal having a gradation correlated with the amount of light received by the PD 12 while the inspection head 16 rotates by a predetermined angle is generated and output from the signal processing unit 62.

  The arithmetic processing unit 60 that has received the reflected light signal from the signal processing unit 62 stores the received signal in the storage unit 65. Further, the arithmetic processing unit 60 uses the reflected light signal stored in the storage unit 65 to generate a two-dimensional image in which the inner peripheral surface 100a of the workpiece 100 is developed in a plane. The two-dimensional image corresponds to an image in which the inner peripheral surface 100a is developed on a plane defined by an orthogonal biaxial coordinate system in which the circumferential direction of the workpiece 100 is the Y-axis direction and the axial direction of the inspection head 16 is the Z-axis direction. To do. Note that, when generating a two-dimensional image in the arithmetic processing unit 60, a two-dimensional image in which defects to be detected are emphasized by performing edge processing, binarization processing, etc. on the original image obtained from the reflected light signal. May be generated. Then, the arithmetic processing unit 60 determines whether or not a defect exceeding an allowable limit exists on the inner peripheral surface 100a by processing the obtained image with a predetermined algorithm, and outputs the determination result to the output unit. 64.

  Next, centering adjustment between the inspection head 16 and the workpiece 100 will be described. This centering adjustment is performed prior to the surface inspection described above. In the surface inspection apparatus 1, the inspection mechanism 2 and the head position adjustment mechanism 7 are adjusted in position so that the axis AX of the inspection head 16 is parallel to the axis of the work 100 supported by the work support device. is set up. In the centering adjustment of this embodiment, it is assumed that the axis AX of the inspection head 16 and the axis of the workpiece 100 are parallel, and the inspection head does not deviate in the XY plane of FIG. 16 is adjusted in the X-axis direction and the Y-axis direction in FIG.

  As shown in FIG. 2, in a state where the mirror 18 is removed from the inspection head 16, the inspection light B <b> 1 is emitted from the front end of the inspection head 16 in a substantially axial direction. When the inspection light B1 passes through the hole of the workpiece 100, the reflected light does not return to the inspection head 16. On the other hand, as shown in FIG. 3, when the inspection light B <b> 1 enters the end surface 100 b of the workpiece 100, the reflected light B <b> 2 returns to the inspection head 16. Therefore, as shown in FIG. 4A, when the workpiece 100 is scanned with the inspection light B1 in the X-axis direction, the inspection light B1 crosses the contour of the inner peripheral surface 100a based on the output signal of the PD 12. The X-axis coordinates Xa and Xb of the point can be specified. As shown in FIG. 4B, when the workpiece 100 is scanned in the Y-axis direction with the inspection light B1, the inspection light B1 crosses the contour of the inner peripheral surface 100a based on the output signal of the PD 12. The Y-axis coordinates Ya and Yb of the point can be specified. Any of these scans can be realized by driving the entire inspection mechanism 2 by the head position adjusting mechanism 7. As shown in FIG. 4C, the center C in the radial direction of the inner peripheral surface 100a is the vertical bisector Lx of the chord Cd1 connecting the X coordinates Xa and Xb and the vertical bisection of the chord Cd2 connecting the Y coordinates Ya and Yb. This is the intersection with the bisector Ly, and the coordinate values Xc and Yc are given by the following equation.

  By adjusting the position of the entire inspection mechanism 2 in the X-axis direction and the Y-axis direction by the head position adjustment mechanism 7 so that the axis AX of the inspection head 16 coincides with the obtained center C, the axis of the inspection head 16 AX can be centered with respect to the inner peripheral surface 100 a of the workpiece 100.

  FIG. 5 shows a centering adjustment routine executed by the arithmetic processing unit 60 for the above-described centering adjustment. Prior to this routine, the inspection head 16 is roughly positioned at a position where the inspection light B1 emitted in the axial direction can cross the workpiece 100 in the X-axis direction and the Y-axis direction. When the centering adjustment routine is started, the arithmetic processing unit 60 first emits the inspection light B1 from the inspection head 16 in the axial direction in step S1, and drives the inspection head 16 in the X-axis direction by the head position adjusting mechanism 7. The workpiece 100 is scanned in the X-axis direction with the inspection light B1. In this case, the movement range of the inspection head 16 is set so that the workpiece 100 is scanned in the X-axis direction with the inspection light B1 within a range including two points of the contour of the inner peripheral surface 100a. For example, the movement range may be set by inputting the inner diameter of the workpiece 100 in advance. The rotation of the inspection head 16 is not necessary.

  In the next step S2, the arithmetic processing unit 60 determines whether or not the reflected light B2 is detected with a light amount of a certain level or more during the scanning in step S1. If the reflected light B2 is not detected even if the region where the end surface 100b of the workpiece 100 should exist is scanned, or if the amount of the reflected light is insufficient even if it is detected, the axis AX of the inspection head 16 and the workpiece 100 The axis may not be parallel. Therefore, when no reflected light is detected in step S2, the arithmetic processing unit 60 skips steps S3 to S7, proceeds to step S8, performs predetermined error processing, and ends the routine. The error process includes a process of outputting an error signal indicating that the axis AX of the inspection head 16 and the axis of the workpiece 100 are in an unbalanced state. Based on the error signal, a message prompting the operator of the apparatus to confirm the parallel state of the axes may be notified. When the surface inspection apparatus 1 has a function of correcting the parallel state of the axis, the parallel state may be corrected based on the error signal. By performing error processing, inconveniences such as deterioration of inspection accuracy when the axis AX of the inspection head 16 and the axis of the workpiece 100 are in a non-parallel state, or contact between the inspection head 16 and the workpiece 100 are avoided. It becomes possible.

  On the other hand, if it is determined in step S2 that reflected light of a certain amount or more has been detected, the arithmetic processing unit 60 proceeds to step S3. In step S3, the arithmetic processing unit 60 refers to the reflected light signal output from the signal processing unit 62 corresponding to the scanning in the X-axis direction, and acquires the X-axis coordinates Xa and Xb. The X-axis coordinates when the intensity of the reflected light signal clearly rises are coordinates Xa and Xb. In subsequent step 4, the arithmetic processing unit 60 drives the inspection head 16 in the Y-axis direction by the head position adjusting mechanism 7 to scan the workpiece 100 in the Y-axis direction with the inspection light B1. Also in this case, the movement range of the inspection head 16 is set so that the workpiece 100 is scanned in the Y-axis direction with the inspection light B1 within a range including two points of the contour of the inner peripheral surface 100a. In the next step S5, the arithmetic processing unit 60 refers to the reflected light signal output from the signal processing unit 62 in response to the scanning in the Y-axis direction, and acquires the Y-axis coordinates Ya and Yb. The Y-axis coordinates when the intensity of the reflected light signal clearly rises are the coordinates Ya and Yb.

  In subsequent step S6, the arithmetic processing unit 60 calculates the coordinates Xc, Yc of the center C of the workpiece 100 from the obtained X-axis coordinates Xa, Xb and Y-axis coordinates Ya, Yb. The calculation formula is as described above. Thereafter, the arithmetic processing unit 60 proceeds to step S7, and drives the head position adjusting mechanism 7 so that the X-axis coordinate and the Y-axis coordinate of the axis AX of the inspection head 16 coincide with the center coordinates Xc, Yc of the workpiece 100. As a result, the axis AX of the inspection head 16 is positioned at the center C of the workpiece 100. After completing the positioning in step S7, the arithmetic processing unit 62 ends the current routine.

  After the inspection head 16 is positioned with respect to the workpiece 100 by the above procedure, the mirror holding cylinder 21 is once removed, the mirror 18 is mounted therein, and the mirror holding cylinder 21 is attached again. Thereafter, the inspection head 16 is driven in the axial direction and the circumferential direction by the linear drive mechanism 30 and the rotational drive mechanism 40 while emitting inspection light from the LD 11, so that the axis AX of the inspection head 16 coincides with the center of the workpiece 100. In this state, the inner peripheral surface 100a can be inspected. In the inspection process, the head position adjusting mechanism 7 is not driven, and the inspection head 16 is held at a fixed position in the X-axis direction and the Y-axis direction.

  According to the above embodiment, the axis line AX of the inspection head 16 can be positioned at the center position C of the workpiece 100 by scanning the workpiece 100 in two axes and detecting the amount of reflected light. The burden required for adjustment can be reduced, and the work efficiency can be improved. No measuring instruments such as dial gauges or jigs are required. Note that the above-described centering adjustment routine is not performed every time the workpiece 100 is inspected. For example, when a large number of workpieces 100 having the same shape and dimensions are inspected one by one, a certain number of workpieces 100 are detected. May be performed periodically each time the

  In the above embodiment, the arithmetic processing unit 60 functions as scanning control means by executing steps S1 and S4, and functions as arithmetic means by executing steps S3, S5, and S6, and executes step S7. Therefore, it functions as positioning control means. The arithmetic processing unit 60 functions as a first coordinate determination unit in step S3, functions as a second coordinate determination unit in step S5, and functions as an intermediate point calculation unit in step S6. Further, the arithmetic processing unit 60 functions as an error processing unit by executing steps S2 and S8. Step S1 corresponds to the first scanning process, step S3 corresponds to the second scanning process, steps S3, S5 and S6 correspond to the calculation process, step S7 corresponds to the positioning process, and step S3 corresponds to the first scanning process. 1 coordinate determination step, step S5 corresponds to the second coordinate determination step, and step S6 corresponds to the intermediate point coordinate calculation step.

  The present invention is not limited to the form described above, and may be implemented in various forms. For example, the configuration of the detection means for irradiating the inspection light and receiving the reflected light is not limited to the above-described form, and the inspection light is irradiated from the outer periphery of the inspection head to the inspection object, and the reflected light is passed through the inspection head. If it can receive light, it can be changed appropriately. The configurations of the linear drive means and the rotation drive means are not limited to the illustrated form, and may be changed as appropriate. The inspection head is not limited to one that can irradiate inspection light in the axial direction by removing the mirror from the mirror holding cylinder. The inspection head may be configured to irradiate the inspection light in the axial direction by retracting the mirror from the optical path of the inspection light. The means for changing the optical path of the inspection light to the outer peripheral side is not limited to a mirror, and various optical components such as a prism may be used. The head position adjusting means is not limited to the configuration for moving the inspection head in the first axial direction and the second axial direction with respect to the object to be inspected. For example, the head position adjusting means may be configured to move the object to be inspected with respect to any one axial direction or both directions. The inspection object is not limited to a cylindrical workpiece, and for example, a valve body of an automatic transmission of a car, a brake master cylinder, or the like may be used as the inspection object. That is, as long as it has at least one inner peripheral surface, various inspection objects can be used as inspection targets of the surface inspection apparatus of the present invention.

The figure which shows schematic structure of the surface inspection apparatus which concerns on one form of this invention. The figure which shows a mode that the test | inspection light irradiated from the front-end | tip part of a test | inspection head passes the hole of a workpiece | work. The figure which shows a mode that the test | inspection light irradiated from the front-end | tip part of a test | inspection head reflects in the end surface of a workpiece | work. The figure which shows two points on the outline of the internal peripheral surface detected when a workpiece | work is scanned to a X-axis direction with test | inspection light. The figure which shows two points on the outline of the internal peripheral surface detected when a workpiece | work is scanned to a Y-axis direction with test | inspection light. The figure which shows the method of calculating | requiring the center position of a workpiece | work geometrically from the point on the outline of the internal peripheral surface detected in the X-axis direction and the Y-axis direction. The flowchart which shows the centering adjustment routine which an arithmetic processing part performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface inspection apparatus 2 Inspection mechanism 5 Detection unit (detection means)
6 Drive unit 7 Head position adjustment mechanism (Head position adjustment means)
DESCRIPTION OF SYMBOLS 11 Laser diode 12 Photo detector 13 Emitting fiber 14 Light receiving fiber 15 Holding cylinder 16 Inspection head 18 Mirror 20 Head main body 21 Mirror holding cylinder 30 Linear drive mechanism (linear drive means)
31 base 40 rotation drive mechanism (rotation drive means)
50 focus adjustment mechanism 60 arithmetic processing unit (scanning control means, arithmetic means, positioning control means)
100 workpieces (inspected object)
100a Inner circumferential surface 100b End face AX Inspection head axis B1 Inspection light irradiated in the axial direction B2 Reflected light returned in the axial direction C Center position of the workpiece

Claims (8)

Irradiating the inspection light from the outer periphery of the inspection head extending in the axial direction toward the inner peripheral surface of the inspection object, and receiving the reflected light from the inspection object with respect to the irradiation of the inspection light through the inspection head, Detection means for outputting a signal corresponding to the amount of the reflected light, linear drive means for moving the inspection head in the axial direction, and rotation drive means for rotating the inspection head around the axis, In the surface inspection apparatus configured such that the inspection head can receive the reflected light from the tip in the axial direction and receive the reflected light returning to the axial direction in response to the irradiation.
Head position adjusting means for moving the inspection head relative to the object to be inspected in a first axial direction and a second axial direction orthogonal to the axial direction;
Range in which the inspection object includes two points on the contour of the inner peripheral surface by inspection light emitted in the axial direction from the tip of the inspection head with respect to each of the first axial direction and the second axial direction Scanning control means for controlling the operation of the head position adjusting means so as to be scanned by:
An arithmetic means for calculating a center position in the radial direction of the inner peripheral surface of the object to be inspected based on signals respectively output from the detection means during scanning in the first and second axial directions;
Positioning control means for controlling the operation of the head position adjusting means so that the axis of the inspection head coincides with the calculated center position;
A surface inspection apparatus comprising:   The computing means determines the coordinates of two points on the contour of the inner peripheral surface in the first axial direction based on an output signal of the detecting means corresponding to scanning in the first axial direction. A second unit for determining the coordinates of two points on the contour of the inner peripheral surface in the second axial direction based on an output signal of the coordinate determining unit and the detecting unit corresponding to the scanning in the second axial direction; A coordinate determination means and a coordinate in the first axial direction of an intermediate point between two coordinates determined by the first coordinate determination means and an intermediate point between the two coordinates determined by the second coordinate determination means; The surface inspection apparatus according to claim 1, further comprising: center coordinate calculation means for calculating coordinates in the second axis direction as coordinates of the center position.   When a signal corresponding to reflected light of a predetermined light amount or more is not output from the detection means during scanning in at least one of the first and second axial directions, the axis of the inspection head and the inspection target The surface inspection apparatus according to claim 1, further comprising an error processing unit that outputs an error signal indicating that the axis of the inner peripheral surface of the object is in a non-parallel state.   The detection means, the linear drive means, and the rotation drive means are disposed on a common base, and the head position adjustment means moves the base toward at least one of the first and second axial directions. The surface inspection apparatus according to claim 1, wherein the surface inspection apparatus is moved. Irradiating the inspection light from the outer periphery of the inspection head extending in the axial direction toward the inner peripheral surface of the inspection object, and receiving the reflected light from the inspection object with respect to the irradiation of the inspection light through the inspection head, Detection means for outputting a signal corresponding to the amount of the reflected light, linear drive means for moving the inspection head in the axial direction, and rotation drive means for rotating the inspection head around the axis, In a surface inspection apparatus configured to irradiate inspection light from the tip in the axial direction and receive reflected light returning to the axial direction in response to the irradiation, the inspection head is configured to inspect the axis of the inspection head. An inspection head centering adjustment method for matching with a center position in a radial direction of the inner peripheral surface of an object,
In a state where inspection light is emitted from the inspection head in the axial direction, the inspection head is moved relative to the object to be inspected in a first axial direction perpendicular to the axial direction. A first scanning step of scanning the inspection object with the inspection light in a range including two points on a contour of a peripheral surface;
In a state where inspection light is emitted from the inspection head in the axial direction, the inspection head is perpendicular to the axial direction with respect to the inspection object and in a second axial direction different from the first axial direction. A second scanning step of scanning the inspection object with the inspection light in a range including two points on the contour of the inner peripheral surface by relatively moving;
A calculation step of calculating a center position in the radial direction of the inner peripheral surface of the object to be inspected based on signals respectively output from the detection means in the first and second scanning steps;
A positioning step of relatively moving the inspection head and the inspection object so that an axis of the inspection head coincides with the calculated center position;
An inspection head centering adjustment method characterized by comprising:   The computing step determines the coordinates of two points on the contour of the inner peripheral surface in the first axial direction based on the output signal of the detection means corresponding to the scanning in the first axial direction. A second step of determining the coordinates of two points on the contour of the inner circumferential surface in the second axial direction based on the coordinate determining step and an output signal of the detection means corresponding to the scanning in the second axial direction; A coordinate determination step and an intermediate point between two coordinates determined in the first coordinate determination step and the first coordinate determination step in the first axis direction, and an intermediate point between the two coordinates determined in the second coordinate determination step. The centering adjustment method according to claim 5, further comprising: a center coordinate calculation step of calculating coordinates in the second axis direction as coordinates of the center position.   When a signal corresponding to reflected light of a predetermined light amount or more is not output from the detection means during scanning in at least one of the first and second axial directions, the axis of the inspection head and the inspection target The centering adjustment method according to claim 5 or 6, further comprising an error processing step of outputting an error signal indicating that the axis of the inner peripheral surface of the object is in a non-parallel state.   In each of the first scanning step, the second scanning step, and the positioning step, the detection unit, the linear driving unit, and the rotational driving unit are at least one of the first and second axial directions. The centering adjustment method according to any one of claims 5 to 7, wherein the centering movement is performed in one direction.

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