How to calibrate the magnification of an internal shape measuring machine

Abstract

To provide a magnification calibration method for an inner surface shape measuring machine that can easily and securely calibrate the magnification of a probe without reference to operator's skill, and the inner surface shape measuring machine.SOLUTION: There is provided a magnification calibration method for an inner surface shape measuring machine that measures an inner surface shape of a thin hole bored in a work, and the method comprises: observing the position of the thin hole for calibration on a standard for calibration, having a cylindrical surface with a first radius and a plane rotated on an axis of rotation parallel with a first direction by work rotating means, by a camera to acquire attitude information on the standard for calibration; aligning the axis of the thin hole for calibration with the axis of rotation on the basis of the acquired attitude information; aligning the axis of a probe with the axis of rotation; and moving, on the basis of the first radius and a width of the probe in a second direction, the probe in the second direction; and detecting the cylindrical surface and plane to calibrate the magnification.SELECTED DRAWING: Figure 43

Description

[Technical field]

[0001] The present invention relates to a technique for measuring the inner shape of a small hole formed in a workpiece. [Background technology]

[0002] Conventionally, there has been known a shape measuring machine that measures the inner shape (roundness, etc.) of a cylindrical workpiece by rotating a detector probe and the workpiece relatively around a rotation axis (see, for example, Patent Document 1). In order to measure the inner shape of the workpiece using such a shape measuring machine, it is necessary to align the rotation axis with the central axis of the workpiece.

[0003] Patent Document 1 discloses a technique for measuring the inner shape of the inner peripheral surface of a cylindrical workpiece placed on a rotating table by contacting the probe (contact piece) of a detector with the inner peripheral surface of the workpiece. In the technique described in Patent Document 1, in order to align the rotation axis with the central axis of the workpiece, the detector probe is contacted with the outer peripheral surface of the workpiece in advance, and the runout of the workpiece is observed at low magnification while rotating the rotating table, and the workpiece placement position is adjusted to reduce the runout. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-145344 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, such a shape measuring machine requires a magnification calibration for the probe, which correlates the output signal of the probe with the actual calibrated displacement. Generally, a calibration tool such as a block gauge or a flick master is used for the magnification calibration, but there is a concern that the probe may be damaged by colliding with the calibration tool. In particular, when the minimum working distance between the probe and the workpiece is small and the measurement range is narrow, the problem becomes more serious. As a countermeasure against this, it is considered that the operator avoids the collision by operating the probe while visually checking the vicinity of the probe tip position with a microscope or the like, but in that case, the operator needs skill and there is a possibility of the probe being damaged due to human error.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a method for calibrating the magnification of an inner surface shape measuring machine, and an inner surface shape measuring machine that can simply and reliably calibrate the magnification of a probe regardless of the skill of the operator. [Means for solving the problem]

[0007] In order to achieve the above object, the following invention is provided.

[0008] A method for calibrating the magnification of an inner surface shape measuring machine according to a first aspect of the present invention is a method for calibrating the magnification of an inner surface shape measuring machine that measures the inner surface shape of a fine hole formed in a workpiece, the inner surface shape measuring machine comprising: work rotation means for rotating the workpiece around a rotation axis parallel to a first direction; and a probe having an elongated shape insertable into the fine hole and detecting the inner surface shape of the fine hole, the method for calibrating the magnification of an inner surface shape measuring machine comprising the steps of: rotating a calibration standard around the rotation axis by the work rotation means, the calibration standard having on its side a cylindrical surface of a first radius and a flat surface parallel to the axis of the cylindrical surface and a distance from the axis of the cylindrical surface that is smaller than the first radius, and having a calibration fine hole coaxial with the cylindrical surface on a first end face perpendicular to the axis of the cylindrical surface; and observing the position of the calibration fine hole of the calibration standard rotated in the standard rotation step with a first camera having an optical axis parallel to the first direction to detect the inner surface shape of the fine hole. The method includes a standard device attitude information acquisition process for acquiring attitude information of the standard device; a standard device attitude control process for aligning the axis of the calibration narrow hole with the rotation axis based on the attitude information of the calibration standard device acquired in the standard device attitude information acquisition process; a probe attitude information acquisition process for acquiring probe attitude information indicating the relative position of the probe axis with respect to the rotation axis; a probe attitude control process for aligning the probe axis with the rotation axis based on the probe attitude information acquired in the probe attitude information acquisition process; a probe moving process for moving the probe whose axis has been aligned with the rotation axis in the probe attitude control process in a second direction based on a first radius; and a standard device detection process for rotating the calibration standard whose axis has been aligned with the rotation axis in the standard device attitude control process by a work rotation means, and detecting cylindrical surfaces and flat surfaces with the moved probe in the probe moving process.

[0009] A second aspect of the present invention relates to a method for calibrating the magnification of an inner surface shape measuring machine, wherein the probe is a non-contact probe having a second radius in a second direction, and the probe moving step moves the probe in the second direction from the position of the rotation axis to a position away by the sum of the first radius, the second radius, and the working distance of the probe.

[0010] In a magnification calibration method for an inner surface shape measuring instrument according to a third aspect of the present invention, the standard device attitude information acquisition process includes an observation control process for observing, with a first camera, a first position of a calibration narrow hole in a calibration standard device at a first rotation angle of a work rotation means, a second position different in a first direction from the first position, and the first position and second position of the calibration narrow hole in the calibration standard device at a second rotation angle different from the first rotation angle of the work rotation means, a position and inclination calculation process for calculating the position and inclination of the calibration narrow hole from the respective coordinates of the observed first position and second position of the calibration narrow hole at the first rotation angle of the work rotation means and the first position and second position of the calibration narrow hole at the second rotation angle of the work rotation means, and an output process for outputting the narrow hole information including the calculated position and inclination of the narrow hole as attitude information of the calibration standard device.

[0011] In a method for calibrating a magnification of an inner surface shape measuring machine according to a fourth aspect of the present invention, a standard detection step detects a position between a first position and a second position in a first direction of a side surface with a probe.

[0012] In a magnification calibration method for an inner surface shape measuring machine according to a fifth aspect of the present invention, a probe attitude information acquisition process acquires probe attitude information from at least three circumferential positions on a rotational orbit centered on a rotation axis by a probe attitude information acquisition means configured to be rotatable integrally with the work rotation means.

[0013] In a method for calibrating a magnification of an inner surface shape measuring machine according to a sixth aspect of the present invention, the probe attitude information acquiring step acquires the probe attitude information from four circumferential positions shifted from each other by 90 degrees on the rotation orbit.

[0014] In a method for calibrating a magnification of an inner surface shape measuring machine according to a seventh aspect of the present invention, the probe attitude information acquisition means includes a second camera that images the probe.

[0015] In a method for calibrating the magnification of an internal shape measuring instrument according to an eighth aspect of the present invention, the calibration standard has a second end face different from the first end face, the second end face being perpendicular to the axis of the cylindrical surface, and the light guide hole is coaxial with the cylindrical surface and communicates with the calibration narrow hole.

[0016] In a method for calibrating the magnification of an inner surface shape measuring machine according to a ninth aspect of the present invention, the standard device attitude control step includes an incidence step of causing light emitted from a light source to enter a light guiding hole.

[0017] An inner surface shape measuring machine according to a tenth aspect of the present invention is an inner surface shape measuring machine for measuring the inner surface shape of a fine hole formed in a work, comprising: work rotation means for rotating the work having the fine hole formed therein, around a rotation axis parallel to a first direction; work adjustment means capable of adjusting the attitude of the work; a probe having an elongated shape insertable into the fine hole and detecting the inner surface shape of the fine hole; probe adjustment means capable of adjusting the attitude of the probe; probe movement means capable of moving the probe in the first direction and in a second direction perpendicular to the first direction; standard rotation control means for rotating, around the rotation axis by the work rotation means, a calibration standard having a cylindrical surface of a first radius on its side, and a flat surface parallel to the axis of the cylindrical surface and the distance between the cylindrical surface and the axis of the cylindrical surface is smaller than the first radius, and having a calibration fine hole coaxial with the cylindrical surface on its first end face perpendicular to the axis of the cylindrical surface; The calibration standard is provided with a standard attitude information acquisition means for observing the position of the calibration narrow hole of the corrective standard with a first camera having an optical axis parallel to a first direction to acquire attitude information of the calibration standard, a standard attitude control means for aligning the axis of the calibration narrow hole with the rotation axis using a work adjustment means based on the acquired attitude information of the calibration standard, a probe attitude information acquisition means for acquiring probe attitude information, a probe attitude control means for aligning the probe axis with the rotation axis using a probe adjustment means based on the acquired probe attitude information, a probe movement control means for moving the probe whose axis has aligned with the rotation axis in a second direction using a probe movement means based on a first radius, and a standard detection control means for rotating the calibration standard whose axis of the narrow hole has aligned with the rotation axis using a work rotation means, and detecting cylindrical surfaces and flat surfaces with the moved probe. Effect of the Invention

[0018] According to the present invention, the magnification calibration of a probe can be performed simply and reliably, regardless of the skill of the operator. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a schematic diagram showing a configuration of an inner surface shape measuring machine. [Diagram 2] 1 is a schematic diagram showing an example of a non-contact and contact probe. [Diagram 3] FIG. 2 is a block diagram showing the electrical configuration of the inner surface shape measuring machine. [Figure 4] 10 is a flowchart showing an example of a process of an alignment method for an inner surface shape measuring machine. [Diagram 5] FIG. 13 is a schematic diagram showing observation of the upper opening of a fine hole by a camera. [Figure 6] 13 is a diagram showing the positional relationship between the rotation axis of a rotating body, the upper opening when the rotating body is at a set angle θ=0°, and an image of the upper opening within the shooting range of the camera. [Figure 7] FIG. 13 is a schematic diagram showing observation of the lower opening of a fine hole by a camera. [Figure 8] 13 is a diagram showing the positional relationship between the rotation axis of a rotating body, a lower opening when the rotating body is at a set angle θ=0°, and an image of the lower opening within the shooting range of the camera. [Figure 9] 13 is a diagram showing the positional relationship between the rotation axis of a rotating body, the upper opening when the rotating body is at a set angle θ=180°, and an image of the upper opening within the shooting range of the camera. [Figure 10] 13 is a diagram showing the positional relationship between the rotation axis of a rotating body, a lower opening when the rotating body is set at an angle θ=180°, and an image of the lower opening within the shooting range of the camera. [Figure 11] 13 is a diagram for explaining movement target coordinates of an upper opening and movement target coordinates of a lower opening. FIG. [Figure 12] FIG. 13 is a diagram showing the relationship between the camera and a small hole in the workpiece caused by the workpiece setting jig. [Figure 13] FIG. 13 is a schematic diagram showing observation of an intermediate position of a fine hole by a camera. [Figure 14] 10 is a schematic diagram showing observation of a small hole in a workpiece by a camera when the position of the small hole is significantly deviated from the rotation axis. FIG. [Figure 15]13 is a diagram showing the trajectory of the central coordinates of the upper opening of a fine hole within the shooting range of a camera when a rotating body is rotated. FIG. [Figure 16] 1 is a diagram showing the optical path of observation light of a lower opening of a fine hole in a workpiece that enters a camera. FIG. [Figure 17] FIG. 13 is a diagram showing the state of observation of the lower opening of a small hole in a workpiece by a camera. [Figure 18] 13 is a diagram showing the insertion of a sponge-like reflector into the lower opening side of a small hole in a workpiece. FIG. [Figure 19] FIG. 13 is a diagram showing the insertion of a clay-like reflector into the lower opening side of a small hole in a workpiece. [Figure 20] 13 is a diagram showing insertion of a scatterer into a lower opening side of a small hole in a workpiece. FIG. [Figure 21] FIG. 11 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine according to a second embodiment. [Figure 22] FIG. 2 is a block diagram showing a configuration of a control device. [Figure 23] 11 is a flowchart showing an example of a flow of probe alignment. [Figure 24] FIG. 13 is a diagram showing an example of a position where a probe is photographed by a camera. [Diagram 25] 1A to 1C are explanatory diagrams showing examples of images captured by a camera at each shooting position. [Figure 26] 13 is a diagram showing a composite image of the first captured image and the third captured image. FIG. [Figure 27] 13 is a diagram showing a composite image of the second captured image and the fourth captured image. FIG. [Figure 28] 13 is a diagram showing another example of the position at which the probe is photographed by the camera. FIG. [Figure 29] FIG. 13 is a diagram showing yet another example of the position at which the probe is photographed by the camera. [Diagram 30] FIG. 11 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine according to a third embodiment. [Diagram 31] FIG. 13 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine according to a fourth embodiment. [Diagram 32] FIG. 13 is a schematic diagram showing a configuration of a main part of an inner surface shape measuring machine according to a fifth embodiment. [Diagram 33] FIG. 13 is a schematic diagram showing a configuration of a main part of an inner surface shape measuring machine according to a sixth embodiment. [Diagram 34] FIG. 13 is a schematic diagram showing a configuration of a main part of an inner surface shape measuring machine according to a seventh embodiment. [Diagram 35] FIG. 13 is a diagram for explaining an application example of the present invention. [Diagram 36] FIG. 13 is a diagram for explaining an application example of the present invention. [Figure 37] FIG. 11 is a schematic diagram showing a state of calibration of the magnification of a probe. [Figure 38] 11A and 11B are diagrams illustrating a collision between a probe and a block gauge. [Figure 39] FIG. 13 is a schematic diagram showing an auto-stop function of the probe. [Diagram 40] FIG. 13 is a schematic view showing the overall configuration of an inner surface shape measuring machine according to an eighth embodiment. [Diagram 41] FIG. 2 is a block diagram showing a configuration of a control device. [Diagram 42] FIG. 2 is a diagram showing a calibration standard (Flick Master) used in this embodiment. [Diagram 43] 11 is a flowchart illustrating an example of a process of a magnification calibration method. [Diagram 44] FIG. 13 is a diagram showing the movement of a probe. [Diagram 45] 13 is a diagram showing a magnification calibration error when there is an error between the probe and the rotation axis. FIG. [Figure 46] FIG. 1 is a schematic diagram of an inner surface shape measuring instrument having a light guiding mechanism. [Figure 47] FIG. 13 is a diagram showing measurement of a calibration standard during magnification calibration. [Figure 48] FIG. 13 shows a calibration standard in which the image alignment slot is a blind hole. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0021] [First embodiment] <Configuration of inner surface shape measuring machine> Fig. 1 is a schematic diagram showing the configuration of an inner surface shape measuring machine 10 according to a first embodiment. The inner surface shape measuring machine 10 is a device that measures the inner surface shape (roundness, etc.) of a small hole H formed in a workpiece W. In this example, the small hole H is a small hole formed along the central axis of the workpiece W. The inner diameter of the small hole H is extremely small (for example, an inner diameter of 500 µm or less). In Fig. 1, the X direction, Y direction, and Z direction are directions perpendicular to each other, the X direction is a horizontal direction, the Y direction is a horizontal direction perpendicular to the X direction, and the Z direction is a vertical direction.

[0022] As shown in FIG. 1, the inner surface shape measuring machine 10 includes a main body base 12, a rotating body 14, a linear tilt stage 16, a workpiece mounting jig 18, a column 20, a carriage 22, an arm 24, a displacement detector 28, and a camera 34.

[0023] The rotating body 14 is fixed on the main body base 12. Inside the main body base 12, there are provided a motor (not shown), an encoder (not shown), and a high-precision rotation mechanism (not shown), which are connected to the rotating body 14. The rotating body 14 rotates about a rotation axis A parallel to the Z direction (an example of a first direction) by being driven by the motor. R The rotation angle of the rotor 14 is detected by a rotation angle signal output from an encoder.

[0024] The linear tilt stage 16 (an example of a linear tilt stage) is supported by the rotating body 14 so as to be movable relative to the rotating body 14. The linear tilt stage 16 translates in the X and Y directions by being driven by a motor (not shown), and can change the position of the workpiece W fixed to the linear tilt stage 16 in a plane perpendicular to the Z direction (in the XY plane). The linear tilt stage 16 also tilts in the X and Y directions by being driven by a motor (not shown), and can change the inclination of the workpiece W fixed to the linear tilt stage 16 with respect to the XY plane.

[0025] The workpiece setting jig 18 is placed on the linear motion tilt stage 16. The workpiece W is set on the workpiece setting jig 18. That is, the workpiece W is fixed to the linear motion tilt stage 16 via the workpiece setting jig 18. The workpiece W has a very small diameter fine hole H. The fine hole H is connected to the inside of the workpiece W through an upper opening O. U (See Figure 5) from the lower opening O D (See Figure 7)

[0026] In order to measure the inner shape, such as the roundness, of the small hole H in the workpiece W using the inner shape measuring machine 10, the central axis A of the small hole H in the workpiece W is H is the rotation axis A of the rotor 14 R The workpiece W must be aligned so that it is coaxial with the rotation axis A. The alignment of the workpiece W will be described later. FIG. 1 shows the state of the workpiece W before alignment. The aligned workpiece W is aligned with the rotation axis A together with the rotor 14. R Rotates around the center.

[0027] Furthermore, a column (support) 20 extending parallel to the Z direction is provided upright on the main body base 12. The column 20 has a lower end fixed to the upper surface of the main body base 12.

[0028] The carriage 22 is supported by the column 20 so as to be movable in the Z direction. The carriage 22 moves in the Z direction by being driven by a motor (not shown). The carriage 22 corresponds to a vertical linear motion mechanism (an example of a first linear motion mechanism) for moving the displacement detector 28 and the camera 34 in the Z direction.

[0029] The arm 24 is supported by the carriage 22 so as to be movable in the X direction (an example of a second direction perpendicular to the first direction). The arm 24 moves in the X direction by being driven by a motor (not shown). The arm 24 corresponds to a horizontal linear motion mechanism for moving the displacement detector 28 and the camera 34 in the X direction.

[0030] The displacement detector 28 is supported by the arm 24. The displacement detector 28 includes a probe 30 of a non-contact or contact type.

[0031] FIG. 2 is a schematic diagram showing an example of the probe 30. 202A in FIG. 2 shows the non-contact type probe 30. The displacement detector 28 (see FIG. 1) equipped with the non-contact type probe 30 includes a light-emitting element (not shown) that emits detection light, and a light-receiving element (not shown) that receives reflected light of the detection light emitted from the light-emitting element. The non-contact type probe 30 includes an optical fiber 38 and a reflecting mirror 40. The light emitted from the light-emitting element (not shown) of the displacement detector 28 (see FIG. 1) is guided to the reflecting mirror 40 by the optical fiber 38, reflected by the reflecting surface of the reflecting mirror 40, and incident on the workpiece W. The reflected light reflected by the workpiece W is incident on the reflecting mirror 40, reflected by the reflecting surface of the reflecting mirror 40, and guided to the optical fiber 38. The reflected light guided to the optical fiber 38 is input to a light-receiving element (not shown) of the displacement detector 28. The displacement detector 28 detects the displacement of the workpiece W based on the reflected light received by the light-receiving element.

[0032] As a method for the non-contact type displacement detector 28, known methods such as a laser interferometer, a white light interferometer, Spectral Domain-Optical Coherence Tomography (SD-OCT), and Swept Source-Optical Coherence Tomography (SS-OCT) can be applied.

[0033] The displacement detector 28 may detect the displacement of the workpiece W in a contact manner. 202B in FIG. 2 shows a contact-type probe 30. The contact-type probe 30 has a contactor 42 at its tip which is biased toward the workpiece W. When the contactor 42 comes into contact with the workpiece W, the contactor 42 is displaced in accordance with the shape of the workpiece W. The displacement of the contactor 42 is transmitted to the displacement detector 28 via the probe 30. The displacement detector 28 detects the displacement of the workpiece W based on the displacement of the contactor 42.

[0034] Known mechanisms such as an LVDT (Linear Variable Differential Transformer), an interferometer, an optical triangulation method, a thin film strain measurement method, etc. may be applied as the displacement detection mechanism of the contact type displacement detector 28. Furthermore, as the displacement detector 28, a method may be applied in which the contactor 42 is vibrated at a resonance frequency and the resonance point is changed by contact.

[0035] Returning to the explanation of Fig. 1, when the roundness of the small hole H in the workpiece W is measured by the inner surface shape measuring machine 10, the probe 30 is moved in the Z direction together with the displacement detector 28 by the carriage 22 and inserted into the small hole H in the workpiece W. The displacement detector 28 detects the displacement of the hole wall (inner surface) of the small hole H by the probe 30.

[0036] The camera 34 has an optical axis A C (see FIG. 12) is supported by the arm 24 so that it is parallel to the Z direction and faces downward.

[0037] The camera 34 includes a coaxial epi-illumination optical system 35 (see FIG. 3, an example of a coaxial illumination optical system) and a magnification optical system (microscope) (not shown) that magnifies and projects an object to be observed. The coaxial epi-illumination optical system 35 includes an illumination light source (not shown) and a microscope (not shown) that projects light from the illumination light source along the optical axis A of the camera 34. C The camera 34 is provided with a half mirror (not shown) that emits illumination light coaxially with the optical axis A of the camera. C The illumination light is irradiated onto the object under observation on the same axis as the object under observation, and an enlarged image of the object under observation can be taken. Although a coaxial epi-illumination is used here, oblique illumination may also be used.

[0038] In the inner surface shape measuring machine 10 configured in this manner, the workpiece W is aligned, the probe 30 is inserted into the fine hole H of the workpiece W, the rotating body 14 is rotated to move the workpiece W and the probe 30 relative to each other, and the displacement of the hole wall of the fine hole H is detected by the displacement detector 28, thereby measuring the roundness of the fine hole H.

[0039] <Electrical configuration of the inner surface shape measuring machine> 3 is a block diagram showing an electrical configuration of the inner surface shape measuring machine 10. The inner surface shape measuring machine 10 includes a control device 50.

[0040] The control device 50 is realized by a general-purpose computer such as a personal computer or a microcomputer. The control device 50 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, etc. In the control device 50, various programs such as a control program stored in the ROM are loaded into the RAM, and the programs loaded into the RAM are executed by the CPU, thereby realizing the functions of each part in the inner surface shape measuring device 10, and various arithmetic processing and control processing are executed via the input / output interface.

[0041] As shown in FIG. 3, the control device 50 includes a measurement control unit 52, a displacement acquisition unit 54, a circularity calculation unit 56, an observation control unit 58, a position and tilt calculation unit 60, a stage control unit 62, and an output unit 63.

[0042] The measurement control unit 52 controls motors (not shown) connected to the carriage 22, the arm 24, and the rotating body 14, and controls the relative position between the probe 30 of the displacement detector 28 and the fine hole H of the workpiece W.

[0043] The displacement acquisition unit 54 controls the displacement detector 28 and acquires the displacement of the hole wall of the fine hole H detected by the displacement detector 28 .

[0044] The roundness calculation unit 56 calculates the roundness of the small hole H from the relative position between the probe 30 and the workpiece W obtained from the measurement control unit 52 and the displacement detected by the displacement detector 28.

[0045] The observation control unit 58 controls the camera 34 and acquires the image captured by the camera 34. The position and tilt calculation unit 60 calculates the position and tilt of the fine hole H in the workpiece W from the image acquired by the observation control unit 58. The stage control unit 62 controls a motor (not shown) that drives the linear motion tilt stage 16 based on the position and tilt of the fine hole H calculated by the position and tilt calculation unit 60, and changes the position and tilt of the linear motion tilt stage 16. The output unit 63 outputs the fine hole information including the position and tilt of the fine hole H acquired from the position and tilt calculation unit 60 to an output interface (not shown).

[0046] <Alignment method> As mentioned above, in order to measure the inner shape such as the roundness of the small hole H in the workpiece W, the central axis A of the small hole H H The axis of rotation A of the rotating body 14 R Alignment is required to match the position of the object with the XY plane. Alignment includes centering, which adjusts the position within the XY plane, and tilting, which adjusts the inclination with respect to the XY plane. The inner surface shape measuring instrument 10 is capable of centering and tilting by the linear motion tilt stage 16.

[0047] 4 is a flow chart showing an example of the process of the alignment method of the inner surface shape measuring machine 10. In this example, it is assumed that a workpiece W having a small hole H is set in advance on a workpiece setting jig 18. The workpiece setting jig 18 is set in such a manner that the lower opening O of the small hole H of the workpiece W is aligned with the lower opening O of the small hole H. D (See Figure 7) with a gap (lower opening O D The workpiece W is fixed in place (without blocking the hole).

[0048] In step S1, the measurement control unit 52 drives a motor (not shown) in accordance with the detection result of an encoder (not shown) of the rotating body 14, and moves (rotates) the rotating body 14 to a position where the rotation angle is the set angle θ = 0° (an example of a first rotation angle).

[0049] In step S2, the measurement control unit 52 drives a motor (not shown) of the arm 24 to move the camera 34 upward in the Z direction of the workpiece W. The measurement control unit 52 also drives a motor (not shown) of the carriage 22 to move the camera 34 in the Z direction, and adjusts the focal position of the camera 34 to the upper opening O of the fine hole H. U (An example of the first position).

[0050] In the next step S3 (an example of an observation control step), the observation control unit 58 captures the upper opening O of the fine hole H by the camera 34. U The position and inclination calculation unit 60 also calculates the upper opening O of the fine hole H at the set angle θ=0°. U Center coordinates (x,y) 0U Calculate.

[0051] FIG. 5 shows the upper opening O of the fine hole H by the camera 34. U 5 is a schematic diagram showing the observation of the workpiece W in cross section. The focal plane F shown in FIG. U is the optical axis A of the camera 34 C 3 and includes the focal point of the camera 34. In this case, the upper opening O U 5 is aligned with the position of the upper opening O U The optical path of the observation light is shown in Fig. 5. 0U is the upper opening O observed by the camera 34 U This is an image of the edge portion (viewed in the Z direction).

[0052] FIG. 6 shows the rotation axis A of the rotor 14. R and the upper opening O of the small hole H of the work W when the set angle θ of the rotor 14 is 0°. U , the imaging range R of the camera 34, and the image I observed in the imaging range R in step S3. 0U 6 is a diagram showing the positional relationship between the workpiece W and the imaging range R. In Fig. 6, the imaging range R is shown as viewed in the Z direction, and the cross section of the workpiece W is shown as viewed in the Y direction.

[0053] The position and inclination calculation unit 60 calculates the position and inclination of the image I 0UFrom the upper opening O of the fine hole H at the set angle θ = 0° U Center coordinates (x,y) 0U Calculate.

[0054] Next, in step S4, the measurement control unit 52 drives a motor (not shown) of the carriage 22 to move the camera 34 in the Z direction, and adjusts the focal position of the camera 34 to the upper opening O of the fine hole H. U The lower opening O is located at a different position in the Z direction from D (An example of the second position).

[0055] In the next step S5 (an example of an observation control step), the observation control unit 58 captures the lower opening O of the fine hole H by the camera 34. D Furthermore, the position and inclination calculation unit 60 calculates the lower opening O of the fine hole H at the set angle θ=0°. D Center coordinates (x,y) 0D Calculate.

[0056] FIG. 7 shows the lower opening O of the fine hole H by the camera 34. D 7 is a schematic diagram showing the observation of the workpiece W in cross section. As shown in FIG. 7, the focal plane F D is the lower opening O of the fine hole H D 7 is aligned with the position of the lower opening O D The optical path of the observation light is shown in Fig. 7. 0D is the lower opening O observed by the camera 34 D This is an image of the edge portion (viewed in the Z direction).

[0057] FIG. 8 shows the rotation axis A of the rotor 14. R and the lower opening O of the small hole H of the work W when the set angle θ of the rotor 14 is 0°. D and the image I observed in step S5 in the photographing range R of the camera 34. 0D 8 is a diagram showing the positional relationship between the workpiece W and the imaging range R. In Fig. 8, the imaging range R is shown as viewed in the Z direction, and the cross section of the workpiece W is shown as viewed in the Y direction.

[0058] The position and inclination calculation unit 60 calculates the position and inclination of the image I0D From the lower opening O of the fine hole H at the set angle θ = 0° D Center coordinates (x,y) 0D Calculate.

[0059] Next, in step S6, the measurement control unit 52 drives a motor (not shown) in accordance with the detection result of an encoder (not shown) of the rotating body 14, and moves the rotating body 14 to a position where the rotation angle is the set angle θ = 180° (an example of a second rotation angle).

[0060] In step S7, the measurement control unit 52 drives a motor (not shown) of the carriage 22 to move the camera 34 in the Z direction, and adjusts the focal position of the camera 34 to the upper opening O. U Adjust to.

[0061] In the next step S8 (an example of an observation control step), the observation control unit 58 captures the upper opening O of the fine hole H by the camera 34. U Furthermore, the position and inclination calculation unit 60 calculates the image I 180U From the upper opening O of the fine hole H at the set angle θ = 180° U Center coordinates (x,y) 180U Calculate.

[0062] FIG. 9 shows the rotation axis A of the rotor 14. R and the upper opening O of the small hole H of the work W when the set angle θ of the rotor 14 is 180°. U and the image I observed in step S8 in the photographing range R of the camera 34. 0U 9 is a diagram showing the positional relationship between the workpiece W and the imaging range R. In Fig. 9, the imaging range R is shown as viewed in the Z direction, and the cross section of the workpiece W is shown as viewed in the Y direction.

[0063] The position and inclination calculation unit 60 calculates the position and inclination of the image I 180U From the upper opening O of the fine hole H at the set angle θ = 180° U Center coordinates (x,y) 180U Calculate.

[0064] Next, in step S9, the measurement control unit 52 drives a motor (not shown) of the carriage 22 to move the camera 34 in the Z direction, and adjusts the focal position of the camera 34 to the lower opening O of the fine hole H. D Adjust to.

[0065] In the next step S10 (an example of an observation control step), the observation control unit 58 captures the lower opening O of the fine hole H by the camera 34. D Furthermore, the position and inclination calculation unit 60 calculates the image I 180D From the lower opening O of the fine hole H at the set angle θ = 180° D Center coordinates (x,y) 180D Calculate.

[0066] FIG. 10 shows the rotation axis A of the rotor 14. R and the lower opening O of the small hole H of the work W when the set angle θ of the rotor 14 is 180°. D and an image I observed in step S10 in the photographing range R of the camera 34. 0D 10 is a diagram showing the positional relationship between the workpiece W and the imaging range R. In Fig. 10, the imaging range R is shown as viewed in the Z direction, and the cross section of the workpiece W is shown as viewed in the Y direction.

[0067] The position and inclination calculation unit 60 calculates the position and inclination of the image I 180D From the lower opening O of the fine hole H at the set angle θ = 180° D Center coordinates (x,y) 180D Calculate.

[0068] In step S11 (an example of a position and inclination calculation step), the position and inclination calculation unit 60 calculates the upper opening O of the fine hole H at the set angle θ=0°. U Center coordinates (x,y) 0U and lower opening O D Center coordinates (x,y) 0D and the upper opening O of the fine hole H at the set angle θ = 180° U Center coordinates (x,y) 180U and lower opening O D Center coordinates (x,y) 180D Therefore, the rotation axis A of the rotor 14 R Center axis A of small hole H in workpiece W H Calculate the position and tilt of

[0069] In step S12, the position and inclination calculation unit 60 calculates the central axis A of the small hole H of the workpiece W. H Position and tilt of and rotation axis A R It is determined whether the deviation from the target value is within a target value. If the deviation is greater than the target value, the control device 50 performs the process of step S13. If the deviation is within the target value, the process of this flowchart ends.

[0070] In step S13, the position and tilt calculation unit 60 calculates the amount of movement of the linear motion tilt stage 16. U Movement target coordinate C U (x,y) and lower opening O D Movement target coordinate C D 11 is a diagram for explaining (x, y). In FIG. 11, the upper opening O of the fine hole H at the set angle θ=0° U Center coordinates (x,y) 0U and lower opening O D Center coordinates (x,y) 0D and the upper opening O of the fine hole H at the set angle θ = 180° U Center coordinates (x,y) 180U and lower opening O D Center coordinates (x,y) 180D and the upper opening O U Movement target coordinate C U (x,y) and the lower opening O D Movement target coordinate C D It shows the positional relationship between (x,y) and .

[0071] As shown in FIG. 11, an upper opening O U Movement target coordinate C U (x,y) is C U (x,y)={(x,y) 0U +(x,y) 180U} / 2 …(Formula 1) Similarly, the lower opening O D Movement target coordinate C D (x,y) is C D (x,y)={(x,y)0D +(x,y) 180D} / 2 …(Formula 2) It can be expressed as:

[0072] The position and inclination calculation unit 60 is U Movement target coordinate C U (x,y) and lower opening O D Movement target coordinate C D From (x, y), the amount of movement of the linear motion tilt stage 16 is calculated. The output unit 63 acquires the amount of movement of the linear motion tilt stage 16 calculated by the position and tilt calculation unit 60 (an example of fine hole information), and outputs it to the stage control unit 62 (an example of an output process).

[0073] In step S14 (an example of a stage control step), the stage control unit 62 drives a motor (not shown) of the linear motion tilt stage 16 based on the amount of movement calculated in step S13, and moves the linear motion tilt stage 16 to a target position. Then, the process proceeds to step S1, and the control device 50 performs the same process. By repeating this process, the inner surface shape measuring machine 10 can obtain the central axis A of the small hole H in the workpiece W. H and the rotation axis A of the rotating body 14 R Keep the deviation within the target value.

[0074] In this way, according to the alignment method of this embodiment, the central axis A of the fine hole H H The axis of rotation A of the rotating body 14 R According to this embodiment, the optical axis A of the camera 34 can be aligned. C The axis of rotation A of the rotating body 14 R Since it is not necessary to match the probe 30 and the probe 30, alignment can be performed with a simple configuration. The alignment method according to this embodiment is effective when the fine hole H is a very small hole with an inner diameter of 500 μm or less. Furthermore, it is particularly effective when the diameter of the fine hole H is 200 μm or less and the diameter of the probe 30 is 100 μm or less. Note that the fine hole H may have a diameter larger than 500 μm.

[0075] Here, the upper opening O is photographed by the camera 34. U and lower opening O DThe set rotation angle θ of the rotating body 14 when observing the workpiece W was set to θ=0° and θ=180°, which are angles different from each other by 180°. H and rotation axis A R The deviation from the target can be calculated with high accuracy.

[0076] In addition, in order for the inner surface shape measuring machine 10 to measure the cylindricity of the workpiece W with high accuracy, the column 20 is aligned with the rotation axis A of the rotor 14. R In this embodiment, the upper opening O of the fine hole H is U and lower opening O D When switching between the observation on the left and the right, the focal position of the camera 34 is moved by using the vertical linear motion mechanism of the carriage 22. Therefore, a focus control mechanism for the camera 34 is not required, and high-precision alignment is possible. For example, since the rotation axis position within the focal plane does not move, it is possible to employ a high-magnification optical system.

[0077] The output unit 63 may also output the amount of movement of the linear motion tilt stage 16 (an example of small hole information) acquired from the position and tilt calculation unit 60 to an output interface (not shown) (an example of an output step). R Center axis A of small hole H in workpiece W H The user may obtain small hole information including the position and inclination of the small hole H in the workpiece W, and output the information to an output interface (not shown) (one example of an output step). The user may manually operate the linear inclination stage 16 based on the output information to adjust the central axis A of the small hole H in the workpiece W. H The axis of rotation A of the rotating body 14 R In this embodiment, the output unit 63 outputs the acquired movement amount to the stage control unit 62.

[0078] <Workpiece installation jig> Lower opening O of narrow hole H D In order to observe this, it is necessary to keep the angle (inclination) of the fine hole H within a certain range when the work W is placed on the work placement jig 18.

[0079] FIG. 12 is a diagram showing the relationship between the camera and the fine hole of the workpiece by the workpiece installation jig. 212A in FIG. 12 indicates the maximum angle with respect to the optical axis A of the observation light incident on the objective lens (not shown) of the camera 34 C As shown in 212A, assuming the numerical aperture of the objective lens of the camera 34 is NA, the maximum angle θ of the observation light incident on the objective lens with respect to the optical axis A of the camera 34 C with respect to the optical axis A of the camera 34 obj and the refractive index of the optical path of the observation light is n, then NA = n×sinθ obj …(Equation 3) has the relationship of. Therefore, assuming the refractive index n of air in the optical path of the observation light is 1.0, and the inclination angle with respect to the rotation axis A of the rotating body 14 of the fine hole H is θ R with respect to the rotation axis A of the rotating body 14 of the fine hole H work then θ work <asin(NA) …(Equation 4) a workpiece installation jig 18 capable of positioning the workpiece W so as to satisfy this is required

[0080] 212B in FIG. 12 shows the relationship between the camera 34 and the workpiece W when having the relationship of θ work <θ obj . In 212B, the workpiece W is shown in cross section. The optical path P shown in 212B is the optical path available for observing the lower opening O D of the observation light incident on the camera 34. Thus, in the case shown in 212B, it is possible to observe the lower opening O D with the camera 34

[0081] 212C in FIG. 12 shows the relationship between the camera 34 and the workpiece W when having the relationship of θ work >θ obj . In 212C, the workpiece W is shown in cross section. In the case shown in 212C, the observation light of the lower opening O D does not reach the camera 34, and it is not possible to observe the lower opening O D with the camera 34

[0082] <Position for observing the fine hole> In the above example, the upper opening O of the fine hole H Uand lower opening O D However, the position at which the fine hole H is observed is not limited to the opening, and may be a midway position of the fine hole H.

[0083] FIG. 13 shows the upper opening O of the fine hole H. U and lower opening O D The intermediate position O is different from the Z-axis position H 13 is a schematic diagram showing an observation by the camera 34 at (an example of the second position). In FIG. 13, the workpiece W is shown in cross section. The small hole H shown in FIG. 13 has a lower opening O D The edge of the opening is rounded (lower opening O D Therefore, in the example shown in FIG. H is the middle position O of the small hole H H The dot-hatched portion shown in FIG. 13 corresponds to the midpoint O H The optical path of the observation light is shown in Fig. 13. 0H is the intermediate position O observed by the camera 34. H This is an image (viewed in the Z direction).

[0084] In this way, the upper opening O of the fine hole H U Or lower opening O D When the edge shape of fine hole H is difficult to observe because of chamfering or R, it is effective to observe a midway position of fine hole H. When using a midway position of fine hole H, the position of fine hole H can be detected by using a method of selecting a high contrast (in focus) area in the image or by using white light interference measurement.

[0085] <When the position of the small hole is significantly offset from the rotation axis> In the above example, when the rotating body 14 was rotated, the thin hole H was always within the shooting range of the camera 34 fixed in the X direction. R However, the small hole H was originally placed close to the rotation axis A of the rotor 14. REven if the fine hole H is arranged significantly shifted from the horizontal axis, the same method can be applied by operating the horizontal linear motion mechanism.

[0086] FIG. 14 shows the rotation axis A of the rotor 14. R 13 is a schematic diagram showing a time series of observations of a fine hole H by a camera 34 when the fine hole H of a workpiece W is positioned significantly shifted from the target position.

[0087] 14 shows a state in which the fine hole H of the workpiece W is not within the shooting range of the camera 34. Here, the measurement control unit 52 controls the rotating body 14 so that the rotation angle is set to θ=θ A The set angle is θ = θ A is the angle at which the small hole H in the work W and the arm 24 overlap when viewed in the Z direction. Set angle θ=θ A The movement to the position may be performed by using a jig for positioning, or the rotating body 14 may be moved to each position of the camera 34 by moving the arm 24, and the fine hole H may be searched for by the camera 34.

[0088] 14B, the observation control unit 58 detects the position P at which the fine hole H comes into the field of view of the camera 34. A 3 shows how the arm 24, which is a horizontal linear motion mechanism, is moved to this position P A In the observation control unit 58, the upper opening O of the fine hole H is captured by the camera 34. U and lower opening O D The position and tilt calculation unit 60 observes the set angle θ=θ A Upper opening O of fine hole H in U Center coordinates (x,y) AU and lower opening O D Center coordinates (x,y) AD Furthermore, the position and tilt calculation unit 60 calculates the position P A Remember.

[0089] 14, the measurement control unit 52 rotates the rotor 14 at a set angle θ=θ A +180°=θ B The figure shows how the image is moved to the position shown.

[0090] 14D, the observation control unit 58 detects the position P where the fine hole H is in the field of view of the camera 34. B 3 shows how the arm 24, which is a horizontal linear motion mechanism, is moved to this position P B In the observation control unit 58, the upper opening O of the fine hole H is captured by the camera 34. U and lower opening O D The position and tilt calculation unit 60 observes the set angle θ=θ B Upper opening O of fine hole H in U Center coordinates (x,y) BU and lower opening O D Center coordinates (x,y) BD Furthermore, the position and tilt calculation unit 60 calculates the position P B Remember.

[0091] The set angle θ=θ A Upper opening O of fine hole H in U Center coordinates (x,y) AU , Lower opening O D Center coordinates (x,y) AD , and the position P of the arm 24 A and the set angle θ=θ B Upper opening O of fine hole H in U Center coordinates (x,y) BU , Lower opening O D Center coordinates (x,y) BD , and the position P of the arm 24 B Therefore, the position and tilt calculation unit 60 calculates the rotation axis A of the rotating body 14. R The position and inclination of the small hole H in the workpiece W relative to the target can be calculated.

[0092] <Another example of calculating the position and inclination of a small hole> In the above example, an example in which observation is performed at two rotation angles has been shown, but the rotation angle of the rotor 14 may be set to three or more angles, or may be set continuously. For example, the position and inclination of the fine hole H may be calculated from the trajectory of the central coordinates.

[0093] FIG. 15 shows the upper opening O of the fine hole H in the photographing range R of the camera 34 when the rotating body 14 is rotated. U The locus of center coordinates T U Here, the trajectory when the rotation angle of the rotor 14 is rotated from the set angle θ=0° to the set angle θ=90° is shown. The position and tilt calculation unit 60 calculates this trajectory T U From the set angle θ = 0°, 15°, 30°, 45°, 60°, 75°, 90°, the center coordinates (x, y) 0U , (x,y) 15U , (x,y) 30U , (x,y) 45U , (x,y) 60U , (x,y) 75U , (x,y) 90U Calculate each of the center coordinates, and calculate the target coordinates, i.e., the rotation axis A. R Calculate the coordinates of .

[0094] In this way, calculation is possible without rotating the rotor 14 by 180 degrees, which enables faster alignment. In addition, since a large amount of information is available when determining the rotation center, it is possible to calculate the movement target coordinates with high accuracy.

[0095] <Light intensity adjustment> 16 is a diagram showing the optical path of observation light for the lower opening of the fine hole of the workpiece W incident on the camera 34. 216A in FIG. 16 shows the optical path of the observation light for the lower opening O of the fine hole H of the workpiece W incident on the camera 34. D 216A shows the optical path of the observation light. 216A shows the workpiece W in cross section. As shown in 216A, the lower opening O D The light path that can be used for observation is small in light intensity. D The observation is performed through the upper opening O U In comparison with the observation of the upper aperture O, the amount of light may be insufficient and this may be difficult. U When observing the lower opening O D The microscope may have a mechanism for increasing the amount of light during observation.

[0096] 216B in FIG. 16 is a lower opening O DIn FIG. 216B, a light source 70 is disposed on the lower opening O to illuminate the small hole H. In FIG. 216B, a cross section of the workpiece W is shown. The light source 70 is disposed on the lower opening O. D The light source 70 is preferably a low-coherence light source in order to reduce speckle noise. For example, an LED (Light Emitting Diode) or an ASE (Amplified Spontaneous Emission) light source can be used as the light source 70. The center of the light source 70 is aligned with the rotation axis A of the rotor 14. R It is more preferable that the value of the sigma-based ...

[0097] In this way, the lower opening O D By placing a light source on the side, the lower opening O D The shape edge of the lower opening O can be emphasized. D This makes it easier to observe the alignment, and enables more accurate alignment.

[0098] <Inserting a reflector> Depending on the shape of the workpiece W, the lower opening O D 17 shows the lower opening O of the small hole H in the work W by the camera 34. D 17 is a diagram showing the state of observation of the workpiece W. In FIG. 17, the workpiece W is shown in cross section. The workpiece W shown in FIG. 17 is a lower opening O of the fine hole H. D The other part of the work W is on the lower opening O D Therefore, as shown in FIG. 17A, the lower opening O of the work W is D The amount of reflected light varies depending on the position, and the lower aperture O D It is difficult to observe.

[0099] In addition, the workpiece W shown in FIG. 17 has a lower opening O of a small hole H. D Therefore, as shown in FIG. 17B, the space for inserting the light source 70 is insufficient, and the lower opening O D It is not possible to place a light source 70 on the side.

[0100] Also, as shown in 217C of FIG. D It is possible to insert a reflector 72 on the lower opening O. D Since the space on the side is narrow, precise positioning is required. In addition, there is a possibility that the reflector 72 and the workpiece W may collide with each other, resulting in damage to the workpiece W.

[0101] To address this issue, the lower opening O of the small hole H in the work W D By inserting a flexible reflector on the lower opening O D The amount of light during observation may be increased.

[0102] Figure 18 shows the lower opening O of a small hole H in a workpiece W. D 18 is a diagram showing the insertion of the sponge-like reflector 80 into the workpiece W. In Fig. 18, 218A shows the workpiece W before the sponge-like reflector 80 is inserted, and 218B shows the workpiece W after the sponge-like reflector 80 is inserted.

[0103] The sponge-like reflector 80 is a light reflecting member having elasticity and flexibility. U (An example of an aperture on the camera side) is incident on the lower aperture O D The light is reflected by the small hole H at the lower opening O (an example of the linear motion tilt stage side). The sponge-like reflector 80 desirably has a color such as white that has a high light reflectance. Since the sponge-like reflector 80 is flexible, the light is reflected by the small hole H at the lower opening O D It can be inserted into the narrow space on the side.

[0104] Such a sponge-like reflector 80 is placed at the lower opening O D By inserting it to the side, the lower opening O D Since the amount of light during observation can be increased, the lower opening O D This makes it easier to observe the reflection surface, and enables more accurate alignment. DSince the reflector 80 is deformed to conform to the shape of the workpiece W on the side, there is no need for precise shape forming or positioning, which has the effect of reducing costs. Furthermore, the sponge-like reflector 80 has the effect of eliminating concerns that it will damage the workpiece W because it is flexible.

[0105] FIG. 19 shows the lower opening O of the small hole H in the work W. D 19 is a diagram showing the insertion of the clay-like reflector 82 into the workpiece W. In Fig. 19, 219A shows the workpiece W before the insertion of the clay-like reflector 82, and 219B shows the workpiece W after the insertion.

[0106] The clay-like reflector 82 is a light reflecting member having plasticity and flexibility. U (An example of an aperture on the camera side) is incident on the lower aperture O D The clay-like reflector 82 is preferably white or other color with high light reflectance. Since the clay-like reflector 82 is flexible, the light is reflected by the small hole H at the lower opening O (an example of an opening on the linear motion tilt stage side). D It can be inserted into the narrow space on the side.

[0107] Such a clay-like reflector 82 is placed at the lower opening O D By inserting it to the side, the lower opening O D Since the amount of light during observation can be increased, the lower opening O D This makes it easier to observe the surface of the object, and enables more accurate alignment. D Since the reflector 82 is deformed to conform to the shape of the workpiece W on the side, there is no need for precise shape forming or positioning, which has the effect of reducing costs. Furthermore, the clay-like reflector 82 has the effect of being flexible, so there is no risk of damaging the workpiece W.

[0108] Furthermore, FIG. 20 shows the lower opening O of the small hole H of the work W. D 20 is a diagram showing the insertion of the scatterer 84 into the workpiece W. In Fig. 20, 220A shows the workpiece W before the insertion of the scatterer 84, and 220B shows the workpiece W after the insertion.

[0109] The scatterer 84 is a sponge with an open-cell structure having elasticity and flexibility. D Since the scatterer 84 is flexible, it is arranged at the lower opening O D The light source 70 is attached to the scatterer 84. The light source 70 causes light to enter the scatterer 84. The light incident on the scatterer 84 from the light source 70 is multiple-scattered inside the scatterer 84 and exits through the lower opening O. D is incident on

[0110] Such a scatterer 84 is placed at the lower opening O D By disposing the light on the lower opening O, the scatterer 84 can form a surface light source by multiple scattering. D The amount of light during observation can be increased by the lower aperture O D This makes it easier to observe the scattering medium 84, and enables more accurate alignment. D Since the scatterer 84 is deformed to conform to the shape of the workpiece W on the side, there is no need for precise shape forming or positioning, which has the effect of reducing costs. Furthermore, there is an effect that the scatterer 84 is flexible and therefore there is no risk of damaging the workpiece W.

[0111] [Second embodiment] <Configuration of inner surface shape measuring machine> Fig. 21 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine 110 of the second embodiment. The inner surface shape measuring machine 110 is a device that measures the inner surface shape (roundness, etc.) of a small hole H formed in a workpiece W. In this example, the small hole H is a through hole formed along the central axis of the workpiece W. The inner diameter of the small hole H is extremely small (for example, the inner diameter is 500 µm or less). In Fig. 21, the X direction, Y direction, and Z direction are directions perpendicular to each other, the X direction is a horizontal direction, the Y direction is a horizontal direction perpendicular to the X direction, and the Z direction is a vertical direction.

[0112] As shown in FIG. 21, the inner surface shape measuring machine 110 includes a main body base 112, a high-precision rotation mechanism 114, a linear motion tilt stage 118, a column 120, a carriage 122, an arm 124, a displacement detector 126, a probe linear motion tilt mechanism 128, a camera 132, and a control device 150.

[0113] The high-precision rotation mechanism 114 is a rotation mechanism for rotating the workpiece W around a rotation axis C, and rotates a linear motion tilt stage 118 (described later) with high precision around the rotation axis C parallel to the Z direction. The high-precision rotation mechanism 114 includes a rotor 116 rotatably mounted on the main body base 112, and the linear motion tilt stage 118 is supported on the upper surface of the rotor 116. The high-precision rotation mechanism 114 includes a motor (not shown) that rotates the rotor 116 with high precision around the rotation axis C, and an encoder (not shown) that detects the rotation angle of the rotor 116.

[0114] The linear motion tilt stage 118 is for placing the workpiece W. The linear motion tilt stage 118 may be a stage that directly supports and fixes the workpiece W, or may be a stage that supports and fixes the workpiece W via a workpiece installation jig (not shown).

[0115] The linear motion tilt stage 118 is supported on the support surface (upper surface) of the rotor 116, and is configured to be rotatable integrally with the rotor 116 about the rotation axis C. As a result, the workpiece W supported and fixed to the linear motion tilt stage 118 is rotatable integrally with the linear motion tilt stage 118 about the rotation axis C. The linear motion tilt stage 118 and the rotor 116 are an example of "workpiece rotation means for rotating the workpiece about the rotation axis."

[0116] The linear tilt stage 118 includes a linear mechanism (centering mechanism) and a tilt mechanism (tilting mechanism) (both not shown). The linear mechanism moves the linear tilt stage 118 in the X and Y directions by driving a motor (not shown) to adjust the position of the linear tilt stage 118 in the XY plane (horizontal plane) perpendicular to the rotation axis C. The tilt mechanism rotates the linear tilt stage 118 around the X and Y directions by driving a motor (not shown) to adjust the tilt of the linear tilt stage 118 with respect to the XY plane. Therefore, by adjusting the position and tilt of the linear tilt stage 118 in the horizontal direction (X and Y directions) by the linear mechanism and the tilt mechanism, it is possible to perform eccentricity correction (centering adjustment) and tilt correction (tilting adjustment) of the central axis of the workpiece W with respect to the rotation axis C.

[0117] A column (support) 120 extending parallel to the Z direction is provided on the main body base 112. The column 120 has a lower end fixed to the upper surface of the main body base 112.

[0118] The carriage 122 is supported by the column 120 so as to be movable in the Z direction. The carriage 122 is configured to be movable in the Z direction by being driven by a motor (not shown).

[0119] The arm 124 is supported by the carriage 122 so as to be movable in the X direction. The arm 124 is configured to be movable in the X direction by being driven by a motor (not shown).

[0120] The displacement detector 126 is supported by the arm 124 via a probe linear motion tilt mechanism 128. The displacement detector 126 has an elongated probe 130 that can be inserted into the small hole H of the workpiece W. The probe 130 detects the shape of the inner surface (measurement surface) of the small hole H of the workpiece W when inserted into the small hole H of the workpiece W. A non-contact probe that detects the inner surface shape without coming into contact with the inner surface of the small hole H of the workpiece W is preferably used as the probe 130.

[0121] The non-contact probe is not particularly limited as long as it can detect the inner shape of the fine hole H in the workpiece W without contacting the inner surface. For example, a probe that applies various techniques such as a laser interferometer, a white light interferometer, SD-OCT (Spectral Domain-Optical Coherence Tomography), or SS-OCT (Swept Source-Optical Coherence Tomography) can be used.

[0122] The probe 130 is not limited to a non-contact probe, and may be a contact probe. The contact probe has a contactor that can come into contact with the inner surface of the fine hole H in the workpiece W, and detects the shape of the inner surface by detecting the displacement of the contactor when it is brought into contact with the inner surface of the fine hole H in the workpiece W. As the contact probe, for example, a probe using various methods such as an LVDT (Linear Variable Differential Transformer), an interferometer, an optical triangulation method, and a thin film distortion measurement method may be used. In addition, a method may be applied in which the contactor of the contact probe is vibrated at a resonance frequency and the resonance point changes due to contact.

[0123] In general, non-contact probes are more suitable for making the diameter smaller than contact probes, and are therefore suitable for measuring the inner shape of a very small diameter fine hole H as in this embodiment.

[0124] The probe linear motion tilt mechanism 128 is provided between the arm 124 and the displacement detector 126. The probe linear motion tilt mechanism 128 includes a linear motion mechanism and a tilt mechanism (both not shown). The linear motion mechanism moves the displacement detector 126 in the X and Y directions by driving a motor (not shown) to adjust the position of the probe 130 in the XY plane (horizontal plane) perpendicular to the rotation axis C. The tilt mechanism rotates the displacement detector 126 around the X and Y directions by driving a motor (not shown) to adjust the tilt of the probe 130 with respect to the XY plane. Therefore, by adjusting the position and tilt of the probe 130 in the horizontal direction (X and Y directions) by the probe linear motion tilt mechanism 128 (linear motion mechanism and tilt mechanism), it is possible to perform relative positioning (probe alignment) between the probe 130 and the rotation axis C. The probe linear motion tilt mechanism 128 is an example of an "adjustment means". Probe alignment, which is a feature of the present invention, will be described later.

[0125] The camera 132 is an area sensor camera (two-dimensional sensor camera) such as a CCD (Charge Coupled Device) camera. The camera 132 is connected (supported) to the rotating body 116 via a camera bracket 134. The camera 132 is arranged so that its shooting direction is perpendicular to the rotation axis C and faces the rotation axis C side (rotation center side). The focus of the camera 132 is adjusted to match the rotation axis C. As a result, the camera 132 can rotate around the rotation axis C together with the rotating body 116, and the camera 132 can capture an image of the probe 130 at any shooting position (circumferential position) on a rotation path K centered on the rotation axis C (see FIG. 24). Note that a known method such as a slip ring or wireless power supply can be applied to supply power to the camera 132. The camera 132 is an example of an "acquisition means", and the captured image captured by the camera 132 is an example of "probe attitude information".

[0126] <Control device> The control device 150 controls the operation of each part of the inner surface shape measuring machine 110 (including the operation of measuring the inner surface shape of the workpiece W and the probe alignment operation described below). The control device 150 is realized by a general-purpose computer such as a personal computer or a microcomputer. The control device 150 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like. In the control device 150, various programs such as a control program stored in the ROM are expanded in the RAM, and the programs expanded in the RAM are executed by the CPU, thereby realizing the functions of each part in the inner surface shape measuring machine 110, and various arithmetic processing or control processing is executed via the input / output interface. The control device 150 is an example of a "control means".

[0127] Fig. 22 is a block diagram showing the configuration of the control device 150. Note that Fig. 22 shows only the configuration related to the operation of probe alignment executed by the inner surface shape measuring machine 110. Note that the control device 150 also includes configuration related to the operation of measuring the inner surface shape of the workpiece W, but since this is not a main part of the present invention, the description will be omitted.

[0128] 22, the control device 150 includes a probe alignment control unit 152. The probe alignment control unit 152 is a functional unit that controls an operation for performing relative position alignment (probe alignment) between the probe 130 and the rotation axis C.

[0129] Here, the configuration of the probe alignment control unit 152 will be explained in detail. The probe alignment control unit 152 includes an imaging control unit 154 , a relative deviation detection unit 156 , and a probe attitude control unit 158 ​​.

[0130] The imaging control unit 154 controls the high-precision rotation mechanism 114 to rotate the camera 132 around the rotation axis C integrally with the rotor 116, thereby changing the imaging position (circumferential position) of the camera 132 with respect to the probe 130 in the circumferential direction centered on the rotation axis C. This enables the camera 132 to image the probe 130 from at least three imaging positions on a rotation orbit K of the camera 132 centered on the rotation axis C. Note that, as will be described later, in this embodiment, the probe 130 is suitably imaged from four imaging positions that are shifted from each other by 90 degrees on the rotation orbit K of the camera 132 (see FIG. 24).

[0131] Moreover, the imaging control unit 154 controls the camera 132 that has moved to each imaging position to capture an image of the probe 130. The imaging control unit 154 causes the image captured by the camera 132 to be transmitted to the relative deviation detection unit 156.

[0132] The relative deviation detection unit 156 detects the relative deviation between the rotation axis C and the probe 130 based on the captured images acquired by the camera 132 at each capturing position. A specific detection method will be described in the probe alignment section below.

[0133] The probe posture control unit 158 ​​controls the probe linear motion tilt mechanism 128 based on the relative deviation detected by the relative deviation detection unit 156. Specifically, the probe posture control unit 158 ​​controls the probe linear motion tilt mechanism 128 to adjust the position and tilt of the probe 130 so that the relative deviation detected by the relative deviation detection unit 156 is eliminated, thereby performing relative alignment between the probe 130 and the rotation axis C.

[0134] <Probe alignment> Next, probe alignment, which is a feature of the present invention, will be described.

[0135] When using the inner surface shape measuring machine 10 to measure the inner surface shape (roundness, etc.) of a fine hole H in a workpiece W, first, the probe 130 is moved in the Z direction together with the displacement detector 126 by the carriage 122, and the probe 130 is inserted into the fine hole H in the workpiece W. Then, with the probe 130 inserted into the fine hole H in the workpiece W, the workpiece W is rotated around the rotation axis C while the probe 130 detects the inner surface shape of the fine hole H. In this manner, the inner surface shape of the fine hole H in the workpiece W is measured.

[0136] Here, in order to insert the probe 130 into the fine hole H before the measurement is started, it is necessary to adjust the attitude (position and inclination) of the probe 130 so that the probe 130 is positioned coaxially with the rotation axis C. If there is a relative misalignment between the probe 130 and the rotation axis C, when an attempt is made to insert the probe 130 into the fine hole H, the probe 130 will collide with a portion of the workpiece W other than the fine hole H, making it difficult to measure the inner shape of the fine hole H.

[0137] Therefore, in this embodiment, before the measurement of the inner surface shape of the fine hole H of the workpiece W is started, the probe 130 and the rotation axis C are aligned relative to each other (probe alignment) so that there is no relative misalignment between them. Note that the eccentricity correction and tilt correction (workpiece alignment) of the central axis of the workpiece W with respect to the rotation axis C are performed by the linear tilt stage 118, and it is assumed that the central axis of the workpiece W is coaxial with the rotation axis C. The workpiece alignment may be performed after the probe alignment or before the probe alignment. For the workpiece alignment, the method described in the first embodiment can be suitably used. For the workpiece alignment, a method other than the method described in the first embodiment may be used.

[0138] FIG. 23 is a flowchart showing an example of the flow of probe alignment.

[0139] 23, when probe alignment is started, first, the imaging control unit 154 controls the high-precision rotation mechanism 114 to rotate the camera 132 together with the rotating body 116 around the rotation axis C (step S20). Then, when the camera 132 moves to a predetermined imaging position on the rotation orbit K of the camera 132 centered on the rotation axis C, the camera 132 images the probe 130 at the imaging position (step S22, an example of an "acquisition step").

[0140] Next, it is determined whether or not imaging at all imaging positions has been completed (step S24). If it is determined that imaging at all imaging positions has not been completed (No in step S24), the rotational movement of the camera 132 (step S10) and the imaging of the probe 130 by the camera 132 (step S22) are repeated until it is determined that imaging at all imaging positions has been completed. Note that whether or not the camera 132 has moved to each imaging position can be determined based on the output of an encoder provided in the high-precision rotation mechanism 114. Note that, as long as it can be determined whether or not the camera 132 has moved to each imaging position, any other configuration can be applied, not limited to an encoder.

[0141] Fig. 24 is a diagram showing an example of the image capturing positions of the probe 130 by the camera 132. As shown in Fig. 24, in the probe alignment in this embodiment, the camera 132 is rotated about the rotation axis C by the rotation movement of the rotating body 116, and the camera 132 captures the image of the probe 130 at a predetermined image capturing position (circumferential position) on the rotation orbit K of the camera 132 centered on the rotation axis C of the rotating body 116. Specifically, the camera 132 captures the image of the probe 130 at four image capturing positions P1 to P4 that are shifted from each other by 90 degrees on the rotation orbit K of the camera 132 centered on the rotation axis C.

[0142] Regarding the planar (XY plane) positional relationship of the four shooting positions P1 to P4, the first shooting position P1 and the third shooting position P3 are opposed to each other in the first direction (Y direction) of two mutually orthogonal directions, and the second shooting position P2 and the fourth shooting position P4 are opposed to each other in the second direction (X direction).

[0143] In this embodiment, the direction in which the camera 132 photographs the probe 130 from the four photographing positions P1 to P4 is the X direction or the Y direction, which is the same as the control direction (movement axis direction) in which the probe 30 is moved linearly or tilted by the probe linear motion tilt mechanism 128.

[0144] In this embodiment, as one of the preferable aspects, the first direction (Y direction) in which the first photographing position P1 and the third photographing position P3 face each other and the second direction (X direction) in which the second photographing position P2 and the fourth photographing position P4 face each other are consistent with the control direction of the probe linear motion tilt mechanism 128, but the present invention is not necessarily limited to this aspect. For example, the direction may be different from the control direction of the probe linear motion tilt mechanism 128, and the first direction and the second direction may not be orthogonal to each other. However, according to the present embodiment, the relative deviation between the probe 130 and the rotation axis C can be simply and easily detected independently in each direction, which is preferable.

[0145] Returning to FIG. 23, when it is determined that the camera 132 has finished photographing the probe 130 at all shooting positions (Yes in step S24), the relative deviation detection unit 156 detects the relative deviation between the probe 130 and the rotation axis C based on the images captured by the camera 132 at each shooting position (step S26).

[0146] Here, detection of the relative deviation between the probe 130 and the rotation axis C will be described in detail.

[0147] Fig. 25 is a diagram showing an example of captured images taken by the camera 132 at each of the capturing positions P1 to P4. In Fig. 25, a first captured image 100A is an image captured at the first capturing position P1, and similarly, a second captured image 100B is an image captured at the second capturing position P2, a third captured image 100C is an image captured at the third capturing position P3, and a fourth captured image 100D is an image captured at the fourth capturing position P4.

[0148] When there is a relative misalignment between the probe 130 and the rotation axis C, for example, as shown in FIG. 25, in the captured images 100A to 100D captured by the camera 132 at each of the capturing positions P1 to P4, the attitude (position and inclination) of the probe 130 differs depending on the capturing position (i.e., the capturing direction of the probe 130 by the camera 132).

[0149] For example, in a first photographed image 100A photographed from one photographing position (first photographing position P1) of two photographing positions (first photographing position P1 and third photographing position P3) facing each other in the first direction (Y direction), the probe 130A is inclined to one side in the second direction (X direction), whereas in a third photographed image 100C photographed from the other photographing position (third photographing position P3), the probe 130C is inclined to the other side in the second direction (X direction). Also, the positions in the second direction (X direction) are shifted toward opposite sides.

[0150] The same is true for the second captured image 100B and the fourth captured image 100D at two shooting positions (second captured position P2 and fourth captured position P4) facing each other in the second direction (X direction), where the positions and inclinations of the probes 130B and 130D are shifted in opposite directions.

[0151] FIG. 26 is a diagram showing a first composite image 102A obtained by combining a first captured image 100A and a third captured image 100C captured from two opposing capturing positions (first capturing position P1 and third capturing position P3) in the first direction (Y direction).

[0152] As shown in FIG. 26, in the first composite image 102A obtained by combining the first photographed image 100A and the third photographed image 100C, a first midline ML1 between the central axis (first probe central axis) L1 of the probe 130A in the first photographed image 100A and the central axis (third probe central axis) L3 of the probe 130C in the third photographed image 100C indicates the position of the rotation axis C in the XZ plane (i.e., the position of the rotation axis C when the probe 30 is viewed from the first direction (Y direction)). The first midline ML1 refers to a straight line passing through the center of the first probe central axis L1 and the third probe central axis L3 in the horizontal direction (X direction) in the first composite image 102A in the vertical direction (Z direction). In other words, the straight line that bisects the space between the first probe central axis L1 and the third probe central axis L3 in the left and right (X direction) in the first composite image 102A is called the first midline ML1.

[0153] The first midline ML1 in the first composite image 102A indicates the position of the rotation axis C. That is, the first midline ML1 indicates a line that is a movement target of the probe 130 in the first composite image 102A (within the XZ plane), and by adjusting the attitude (position and inclination) of the probe 130 so that the probe 130 coincides with the first midline ML1, it is possible to eliminate the relative deviation between the rotation axis C and the probe 130 in the XZ plane.

[0154] FIG. 27 is a diagram showing a composite image 102B obtained by combining a second captured image 100B and a fourth captured image 100D captured from two capturing positions (second capturing position P2 and fourth capturing position P4) facing each other in the second direction (X direction).

[0155] As shown in FIG. 27, in the second composite image 102B obtained by combining the second photographed image 100B and the fourth photographed image 100D, a second midline ML2 between the central axis (second probe central axis) L2 of the probe 130B in the second photographed image 100B and the central axis (fourth probe central axis) L4 of the probe 130D in the fourth photographed image 100D indicates the position of the rotation axis C in the YZ plane (i.e., the position of the rotation axis C when the probe 130 is viewed from the second direction (X direction)). The second midline ML2 refers to a straight line passing through the center of the second probe central axis L2 and the fourth probe central axis L4 in the horizontal direction (X direction) in the second composite image 102B in the vertical direction (Z direction). In other words, the straight line that bisects the space between the second probe central axis L2 and the fourth probe central axis L4 in the left and right (X direction) in the second composite image 102B is called the second midline ML2.

[0156] The second midline ML2 in the second composite image 102B indicates the position of the rotation axis C. That is, the second midline ML2 indicates a line that is a movement target of the probe 130 in the second composite image 102B (in the YZ plane), and by adjusting the attitude (position and inclination) of the probe 130 so that the probe 130 coincides with the second midline ML2, it is possible to eliminate the relative deviation between the rotation axis C and the probe 130 in the YZ plane.

[0157] Therefore, by calculating the two midlines ML1, ML2 mentioned above based on the images captured by the camera 132 at four shooting positions P1 to P4 that are shifted by 90 degrees from each other on the rotational orbit K of the camera 132 centered on the rotational axis C, the rotational axis C (center of rotation) which is the movement target of the probe 130 can be detected, and the relative deviation between the rotational axis C and the probe 130 can be adjusted independently in each direction (X direction and Y direction).

[0158] Therefore, in the probe alignment of this embodiment, when one of the two probes 130 in the first composite image 102A shown in Fig. 26 is set as the reference probe (in this example, the probe 130A in the first captured image 100A), the relative deviation detection unit 156 detects, as the tilt movement amount θ, the tilt angle (rotation angle around the Y direction) for making the probe central axis of the reference probe parallel to the first midline ML1, and detects, as the linear movement amount Dx, the movement distance in the X direction required for making the probe central axis of the reference probe coincide with the first midline ML1 when the probe central axis of the reference probe is tilted by the tilt movement amount θ to be parallel to the first midline ML1. The linear movement amount Dx corresponds to the distance in the direction along the movement axis in the X direction of the probe linear motion tilt mechanism 128 (see Fig. 26).

[0159] 27, when one of the two probes 130 is set as the reference probe (in this example, the probe 130B in the second photographed image 100B), the relative deviation detection unit 156 detects, as the tilt movement amount φ, the tilt angle (rotation angle about the X direction) for making the probe central axis of the reference probe parallel to the second midline ML2, and detects, as the linear movement amount Dy, the movement distance in the Y direction required for making the probe central axis of the reference probe coincide with the second midline ML2 when the probe central axis of the reference probe is tilted by the tilt movement amount φ to be parallel to the second midline ML2. The linear movement amount Dy corresponds to the distance in the direction along the movement axis in the Y direction of the probe linear motion tilt mechanism 128 (see FIG. 27).

[0160] The relative deviation detection unit 156 can calculate the probe central axes C1 to C4, midlines ML1 and ML2, linear movement amounts Dx and Dy, and tilt movement amounts θ and φ from each of the composite images 102A and 102B by known image processing such as edge extraction.

[0161] In this way, when the relative deviation detection unit 156 detects the relative deviation between the probe 130 and the rotation axis C in each direction independently based on the captured images captured by the camera 132 at each capturing position (step S26), the probe attitude control unit 158 ​​controls the probe linear motion tilt mechanism 128 based on the result detected by the relative deviation detection unit 156. Specifically, the probe attitude control unit 158 ​​controls the probe linear motion tilt mechanism 128 to move the probe 130 by a linear motion movement amount Dx in the X direction and by a linear motion movement amount Dy in the Y direction, and tilts the probe by a tilt movement amount φ around the X direction and by a tilt movement amount θ around the Y direction (step S28, an example of an "adjustment step"). The direction (orientation) in which the probe linear motion tilt mechanism 128 is moved or tilted is determined depending on which probe is set as the reference probe in the composite images 102A and 102B shown in FIG. 26 or FIG. 27.

[0162] In this manner, when the probe attitude control unit 158 ​​controls the probe linear motion tilt mechanism 128 to change the attitude of the probe 130 based on the result detected by the relative deviation detection unit 156, the relative deviation between the probe 130 and the rotation axis C in the three-dimensional space disappears. This is the end of this flowchart.

[0163] <Effects> According to the probe alignment in this embodiment, the relative deviation between the probe 130 and the rotation axis C can be detected independently in each direction (X direction and Y direction) based on four captured images 100A to 100D of the probe 130 captured by the camera 132 at four capturing positions P1 to P4 shifted by 90 degrees from each other on the rotation orbit K of the camera 132 centered on the rotation axis C of the rotor 116. This makes it possible to control the attitude (position and inclination) of the probe 130 independently in each direction by the probe linear motion tilt mechanism 128, and it becomes possible to eliminate the relative deviation between the probe 130 and the rotation axis C with high accuracy. Therefore, even if the fine hole H of the work W is a very small diameter hole with an inner diameter of about 140 μm and the probe 130 is a very small diameter probe with an outer diameter of about 80 μm, for example, it becomes possible to perform the probe alignment with high accuracy and easily. Therefore, it becomes possible to stably and reliably measure the inner shape of the fine hole H without the probe 130 colliding with the part other than the fine hole H of the work W.

[0164] Furthermore, according to the probe alignment of this embodiment, the camera 132 that rotates and moves integrally with the rotor 116 is used to relatively compare images captured from a plurality of different directions to detect the position of the rotation axis C (center of rotation) that is the movement target of the probe 130. Therefore, even if the camera 132 is attached to the camera bracket 134 with a positional deviation in a predetermined direction, causing a deviation in the relative positional relationship between the camera 132 and the rotation axis C, for example, it is possible to perform accurate relative alignment between the probe 130 and the rotation axis C, and precision in attaching the camera 132 is not required.

[0165] Furthermore, in the probe alignment of this embodiment, the relative position between the camera 132 and the probe 130 is changed in the circumferential direction around the rotation axis C to perform imaging. Therefore, even if the position of the rotation axis C is unclear or the rotation axis C is tilted, it is possible to accurately align the relative position between the probe 130 and the rotation axis C from the images captured by the camera 132 at each of the imaging positions P1 to P4.

[0166] <Modification> In the probe alignment of this embodiment, the relative misalignment between the probe 130 and the rotation axis C is detected independently in each direction based on four captured images 100A to 100D of the probe 130 captured by the camera 132 at four shooting positions P1 to P4 shifted by 90 degrees from each other on the rotation orbit K of the camera 132 centered on the rotation axis C of the rotating body 116. However, this is not limited to this, and for example, as shown in Figure 28, the probe 130 may be captured by the camera 132 from at least three shooting positions on the rotation orbit K of the camera 132 centered on the rotation axis C of the rotating body 116.

[0167] That is, if the relative deviation between the probe 130 and the rotation axis C can be detected independently in each direction, it is sufficient that the camera 132 captures images of the probe 130 from at least three directions centered on the rotation axis C. In this case, the relative deviation between the probe 130 and the rotation axis C can be detected independently in each direction by relatively comparing the images captured by the camera 132 at each capturing position in relation to position information (rotation angle, rotation radius, etc.) regarding each capturing position. Then, based on the detected relative deviation, it becomes possible to control the attitude of the probe 130 independently in each direction by the probe linear motion tilt mechanism 128. This makes it possible to eliminate the relative deviation between the probe 130 and the rotation axis C.

[0168] 29, the camera 132 may continuously capture images of the probe 130 at a fixed interval while rotating the camera 132 by the rotational movement of the rotor 116. In this case, it becomes possible to use a large number of captured images, and therefore it is possible to perform probe alignment with high accuracy. Also, by continuously capturing images of the probe 130 while the camera 132 is rotating, it becomes possible to limit the range in which the camera 132 rotates to a certain range, and therefore it becomes possible to perform probe alignment more efficiently in a shorter time.

[0169] In this embodiment, a configuration is adopted in which the camera 132 is attached to the rotating body 116 via a camera bracket 134, but this is not limited to this, and any configuration can be appropriately adopted as long as the camera 132 is capable of rotating at least around the rotation axis C that is the subject of alignment with the probe 130.

[0170] [Third embodiment] Fig. 30 is a schematic diagram showing the configuration of an inner surface shape measuring machine 110A of the third embodiment. As shown in Fig. 30, in the inner surface shape measuring machine 110A of the third embodiment, a camera 132 is attached to a linear tilt stage 118 via a camera bracket 134. The shooting direction of the camera 132 is the same as in the second embodiment described above, and faces the rotation axis C side (probe 130 side) which is the center of rotation. The focus of the camera 132 is adjusted to match the rotation axis C, and the probe 130 arranged near the rotation axis C can be photographed. In the third embodiment, the camera 132 can rotate around the rotation axis C together with the rotating body 116, and probe alignment can be performed in the same manner as in the second embodiment described above.

[0171] [Fourth embodiment] Fig. 31 is a schematic diagram showing the configuration of an inner surface shape measuring machine 110B of the fourth embodiment. As shown in Fig. 31, the inner surface shape measuring machine 110B of the fourth embodiment further includes an illumination device 136 at a position facing the camera 132 across the rotation axis C, in addition to the configuration of the inner surface shape measuring machine 110 of the second embodiment.

[0172] The lighting device 136 is attached to the rotating body 116 via a lighting device bracket 138, and can rotate integrally with the rotating body 116 around a rotation axis C. This lighting device 136 is a surface-emitting lighting device capable of emitting light from a surface. The lighting device 136 is an example of a "surface-emitting lighting means."

[0173] According to the fourth embodiment, when the camera 132 photographs the probe 130 while rotating the camera 132 around the rotation axis C together with the rotating body 116, the illumination device 136 rotates around the rotation axis C together with the rotating body 116 at a position facing the camera 132. Therefore, the camera 132 photographs the probe 130 while maintaining the relative positional relationship between the camera 132 and the illumination device 136, so that the probe 130 can be photographed under the same illumination conditions regardless of the photographing position of the camera 132. This makes it possible to prevent a decrease in detection accuracy due to differences in illumination conditions, and to perform probe alignment with higher accuracy. The illumination device 136 is preferably a surface-emitting illumination, but is not necessarily limited to surface-emitting illumination.

[0174] The fourth embodiment is not limited to the second embodiment, but can also be applied to the third embodiment in the same manner.

[0175] [Fifth embodiment] Fig. 32 is a schematic diagram showing the main configuration of the inner surface shape measuring instrument of the fifth embodiment. In Fig. 32, 200A, 200B, and 200C are a front view of the probe 130 and the two line sensor cameras 170 and 172 as seen from the Y direction, a side view as seen from the X direction, and a bottom view as seen from the Z direction, respectively.

[0176] In each of the above-described embodiments, an area sensor camera is used as the camera 132. However, the fifth embodiment is different in that two line sensor cameras (one-dimensional sensor cameras) 170, 172 are used.

[0177] As shown in Fig. 32, the two line sensor cameras 170, 172 are cameras that capture images of linear (line-shaped) areas extending in a horizontal direction (Y direction in Fig. 32) perpendicular to the Z direction. The two line sensor cameras 170, 172 are parallel to each other and arranged at a predetermined interval in the Z direction. Similarly to the camera 132 of the second embodiment, the two line sensor cameras 170, 172 are attached to the rotating body 116 (see Fig. 21) via a line sensor camera bracket (not shown).

[0178] Further, an illumination device 174 is provided at a position facing the two line sensor cameras 170, 172. The probe 130 is disposed between the two line sensor cameras 170, 172 and the illumination device 174. As in the fourth embodiment, the illumination device 174 is attached to the rotating body 116 (see FIG. 21) via an illumination device bracket (not shown). Further, as the illumination device 174, an illumination device capable of surface emission is preferably used, but is not necessarily limited to surface emission.

[0179] In the fifth embodiment, the camera 132 is rotated around the rotation axis C together with the rotating body 116, and the probe 130 is photographed by the two line sensor cameras 170, 172 at at least three photographing positions (preferably four photographing positions shifted by 90 degrees in the rotation direction). Then, by analyzing the photographed images taken by the two line sensor cameras 170, 172 at each photographing position, it is possible to calculate the position of the probe 130 in the photographing area of ​​each line sensor camera 170, 172. Therefore, by combining the photographed images taken by the two line sensor cameras 170, 172 at each photographing position, information (probe attitude information) equivalent to the image taken by the camera 132 in the second embodiment can be obtained, and the relative deviation between the probe 130 and the rotation axis C can be detected. Therefore, similar to the second embodiment, it is possible to perform probe alignment with high accuracy.

[0180] In the fifth embodiment, similarly to the fourth embodiment, an illumination device 174 is provided at a position facing the two line sensor cameras 170 and 172, and the two line sensor cameras 170 and 172 and the illumination device 174 are configured to be rotatable around the rotation axis C integrally with the rotating body 116 with the probe 130 disposed between the two line sensor cameras 170 and 172 and the illumination device 174. Therefore, the probe 130 is photographed by the two line sensor cameras 170 and 172 while the relative positional relationship between the two line sensor cameras 170 and 172 and the illumination device 174 is maintained, so that the probe 130 can be photographed under the same illumination conditions regardless of the photographing positions of the two line sensor cameras 170 and 172. This makes it possible to prevent a decrease in detection accuracy due to differences in illumination conditions, and to perform probe alignment accurately and easily.

[0181] [Sixth embodiment] Fig. 33 is a schematic diagram showing the main configuration of the inner surface shape measuring instrument of the sixth embodiment. In Fig. 33, 300A, 300B, and 300C respectively show a front view of the probe 130 and two line sensor cameras 170 and 172 as seen from the Y direction, a side view as seen from the X direction, and a bottom view as seen from the Z direction.

[0182] In the above-described fifth embodiment, a lighting device 174 (see FIG. 32) was provided in a position facing the two line sensor cameras 170, 172, whereas in the sixth embodiment, line laser light sources 176, 178 are provided above the line sensor cameras 170, 172, respectively.

[0183] The line laser light sources 176, 178 irradiate line lasers (line-shaped laser beams) R1, R2 onto the line-shaped imaging areas of the corresponding line sensor cameras 170, 172. The line laser light sources 176, 178 are attached to the rotating body 116 (see FIG. 21) together with the line sensor cameras 170, 172 via a line sensor camera bracket (not shown), and are rotatable around the rotation axis C together with the rotating body 116.

[0184] In the sixth embodiment, similarly to the fifth embodiment, by combining images captured by the two line sensor cameras 170, 172 at each capturing position, it is possible to obtain information (probe attitude information) equivalent to the image captured by the camera 132 in the second embodiment, and to detect the relative deviation between the probe 130 and the rotation axis C. Therefore, similarly to the second embodiment, it is possible to perform probe alignment easily with high accuracy.

[0185] Furthermore, in the sixth embodiment, the probe 130 is photographed by the two line sensor cameras 170, 172 while maintaining the relative positional relationship between the two line sensor cameras 170, 172 and the two line laser light sources 176, 178, so that it becomes possible to photograph the probe 130 under the same lighting conditions regardless of the photographing positions of the two line sensor cameras 170, 172.

[0186] In addition, in Figure 33, a configuration in which two line laser light sources 176, 178 are arranged above each line sensor camera 170, 172 is shown as an example, but the positions at which the two line laser light sources 176, 178 are arranged are not particularly limited as long as they can irradiate a line laser onto the shooting area of ​​each line sensor camera 170, 172.

[0187] [Seventh embodiment] Fig. 34 is a schematic diagram showing the main configuration of the inner surface shape measuring instrument of the seventh embodiment. Note that Fig. 34 is a front view of the probe 130 and the two optical distance measuring sensors 180, 182 as viewed from the Y direction.

[0188] In each of the above embodiments, an imaging device (area sensor camera or line sensor camera) that images the probe 130 from each imaging position is used as an acquisition means for acquiring probe posture information to detect the relative deviation between the probe 130 and the rotation axis C, whereas in the seventh embodiment, two optical distance measuring sensors 180, 182 that measure distance using light are used.

[0189] As shown in Fig. 34, the two optical distance measuring sensors 180, 182 are arranged at a predetermined interval in the Z direction and are attached to the rotating body 116 via a bracket (not shown). The two optical distance measuring sensors 180, 182 measure distance by emitting light and detecting the reflected light. The two optical distance measuring sensors 180, 182 are sensors whose detection principle is triangulation, and for example, PSD (Position Sensitive Detector) type, CMOS (Complementary Metal-Oxide Semiconductor) type, or CCD (Charge Coupled Device) type can be applied. The detection principle of the triangulation method is well known, so a description thereof will be omitted here.

[0190] According to the seventh embodiment, the two optical distance measuring sensors 180, 182 are rotated around the rotation axis C integrally with the rotating body 116, and the two optical distance measuring sensors 180, 182 measure the distance to the probe 30 at at least three measurement positions (preferably four measurement positions shifted by 90 degrees in the rotation direction). Then, by analyzing the relationship between the distance measured by the two optical distance measuring sensors 180, 182 at each measurement position and each measurement position, information (probe attitude information) equivalent to the image captured by the camera 132 in the second embodiment can be obtained, and the relative deviation between the probe 130 and the rotation axis C can be detected. Therefore, similar to the second embodiment, it is possible to perform probe alignment easily with high accuracy.

[0191] In the seventh embodiment, as an example of an acquisition means for acquiring probe posture information for detecting the relative deviation between the probe 130 and the rotation axis C, a case where two optical distance measuring sensors 180, 182 are used is shown as an example other than an imaging device (area sensor camera or line sensor camera). However, any means capable of acquiring probe posture information for detecting the relative deviation between the probe 130 and the rotation axis C may be used, and for example, a laser type, LED (Light Emitting Diode) type, ultrasonic type or eddy current type length measuring sensor may be applied.

[0192] [Application example] According to the second to seventh embodiments, the attitude (position and inclination) of the probe 130 with respect to the rotation axis C can be detected. Therefore, not only can the probe 130 be aligned with the rotation axis C, but the probe 130 can also be adjusted to a position inclined by a required angle. For example, as shown in FIG. 35, when measuring a tapered surface in which the inner surface of a fine hole H is inclined with respect to the rotation axis C, it is possible to set the probe angle (the inclination angle of the probe 130) following the inclination angle (taper angle) of the tapered surface. As a result, for example, when a non-contact probe is used, the measurement light emitted from the probe 130 is irradiated from the normal direction perpendicular to the tapered surface (surface to be measured), so that more sensitive and highly accurate measurement is possible. In addition, as shown in FIG. 36, it is also possible to accurately calculate the difference in the measurement target position depending on the attitude of the probe 130.

[0193] [Magnification calibration] In the inner surface shape measuring machines 10, 110, 110A, and 110B, a magnification calibration is required for the probes 30 and 130, respectively, which associates the output signals of the probes 30 and 130 with the actual calibrated displacement amounts.

[0194] 37 is a schematic diagram showing the state of magnification calibration of the probe 130. Here, an example is shown in which the probe 130 is a non-contact probe.

[0195] In Fig. 37, 310A is a diagram showing magnification calibration using the block gauge 210. The block gauge 210 has a calibrated step amount d c When the block gauge 210 is used, the measurement surface 210A and the measurement surface 210B are measured by the probe 130, and the difference between the output signal when the measurement surface 210A is measured and the output signal when the measurement surface 210B is measured and the calibrated step amount d c By associating this with the magnification, it is possible to perform magnification calibration.

[0196] In Fig. 37, 310B is a diagram showing magnification calibration using the screw-type magnification calibrator 212. The screw-type magnification calibrator 212 has a measurement surface 212A at the left end, and a movement amount d calibrated in the X direction by rotation of a screw (not shown) is c When the screw-type magnification calibrator 212 is used, the measurement surface 210A is measured before and after the screw-type magnification calibrator 212 is moved in the probe 130, and the difference between the output signal measured before the movement and the output signal measured after the movement and the calibrated movement amount d c By associating this with the magnification, it is possible to perform magnification calibration.

[0197] In Fig. 37, 310C is a diagram showing magnification calibration using the calibration standard (flick master) 214. 310C also shows a top view of the calibration standard 214. The calibration standard 214 has a substantially cylindrical shape, and on its outer circumferential surface (side surface), a cylindrical surface 214A and a part of the cylindrical surface 214A are calibrated by a cutting amount d c When the calibration standard 214 is used, the calibration standard 214 is rotated around the axis of the cylindrical surface 214A, the cylindrical surface 214A and the flat surface 214B are measured by the probe 130, and the difference between the output signal when the cylindrical surface 214A is measured and the output signal when the flat surface 214B is measured is calculated as the calibrated cutting amount d c By associating this with the magnification, it is possible to perform magnification calibration.

[0198] Here, when performing magnification calibration of the probe 130, there is a possibility that the probe 130 may collide with a calibration tool and be damaged. Figure 38 is a diagram showing a collision between the probe 130 and a block gauge 210 as an example.

[0199] When a contact probe is used as the probe 130, a function called auto-stop can be used to bring the probe into contact with a calibration tool.

[0200] Fig. 39 is a schematic diagram showing the auto-stop function of the probe 130. In Fig. 39, 320A is a diagram showing the state where the contact-type probe 130 is moved in the X direction to approach the block gauge 210. Also, in Fig. 39, 320B is a diagram showing the state where the probe 130 comes into contact with the block gauge 210 and the movement in the X direction is stopped. In this way, the auto-stop function that detects the contact of the probe 130 and stops it at a predetermined pressing amount prevents damage to the probe 130 and enables measurement of the block gauge 210.

[0201] On the other hand, non-contact probes such as those using optical interference can detect relative displacement but cannot detect absolute distance values. Therefore, the relative position between probe 130 and the calibration tool cannot be detected using only the displacement information of probe 130, which poses the risk of collision.

[0202] [Eighth embodiment] <Configuration of inner surface shape measuring machine> Fig. 40 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine 400 according to an eighth embodiment. The same reference numerals are used for parts common to the inner surface shape measuring machines 10 and 110, and detailed description thereof will be omitted. The inner surface shape measuring machine 400 is a machine that measures the inner surface shape of a fine hole H formed in a workpiece W, and further is a machine that automates magnification calibration. The inner surface shape measuring machine 400 is a machine that can perform the alignment of the workpiece W described in the first embodiment and the probe alignment described in the second embodiment. Also, instead of the second embodiment, the probe alignment of the third to seventh embodiments may be performed.

[0203] As shown in FIG. 40, the inner surface shape measuring machine 400 includes a workpiece mounting jig 18, a camera 34, a main body base 112, a high-precision rotation mechanism 114, a linear motion tilt stage 118, a column 120, a carriage 122, an arm 124, a displacement detector 126, a probe linear motion tilt mechanism 128, a camera 132, and a control device 410.

[0204] The workpiece setting jig 18 is placed on the linear motion tilt stage 118, and the workpiece W is set on the workpiece setting jig 18. That is, the workpiece W is fixed to the linear motion tilt stage 118 via the workpiece setting jig 18. The linear motion tilt stage 118 is an example of a "workpiece adjustment means capable of adjusting the posture of the workpiece."

[0205] The arm 124 supports the displacement detector 126 and the camera 34 in a line in the X direction. C (see FIG. 12) supports the camera 34 in a manner that is parallel to the Z direction and faces downward.

[0206] The camera 34 is an area sensor camera such as a CCD camera, and includes a coaxial epi-illumination optical system 35 (see FIG. 41) and a magnification optical system (microscope) (not shown) that magnifies and projects an object to be observed. The camera 34 is an example of a “first camera.”

[0207] The carriage 122 and the arm 124 are an example of a "probe moving means." The probe linear motion tilt mechanism 128 is an example of a "probe adjusting means."

[0208] The probe 130 is a non-contact type probe that detects the shape of the inner surface of the small hole H in the workpiece W without contacting the inner surface. The probe 130 has a cylindrical shape with a radius r4 and a central axis 130E. The radius r4 is an example of a "second radius."

[0209] The camera 132 is an example of a "probe attitude information acquisition means" and a "second camera."

[0210] <Control device> The control device 410 controls the operation of each part of the inner surface shape measuring machine 400. Fig. 41 is a block diagram showing the configuration of the control device 410. Note that parts common to the block diagrams shown in Fig. 3 and Fig. 22 are given the same reference numerals, and detailed explanations will be omitted.

[0211] As shown in FIG. 41, the control device 410 includes an inner surface shape measuring unit 412, a standard alignment control unit 414, and a probe alignment control unit 152.

[0212] The inner surface shape measuring unit 412 includes a measurement control unit 52, a displacement acquiring unit 54, and a roundness calculating unit 56. The measurement control unit 52 is an example of a "standard rotation control means", a "probe movement control means", and a "standard detection control means".

[0213] The standard alignment control unit 414 includes an observation control unit 58, a position and tilt calculation unit 60, a stage control unit 62, and an output unit 63. The position and tilt calculation unit 60 is an example of a "standard attitude information acquisition means". The stage control unit 62 is an example of a "standard attitude control means".

[0214] The probe alignment control unit 152 also includes an imaging control unit 154, a relative deviation detection unit 156, and a probe attitude control unit 158. The probe attitude control unit 158 ​​is an example of a "probe attitude control means."

[0215] <Calibration standard> Fig. 42 is a diagram showing a calibration standard (flick master) 420 used in this embodiment. In Fig. 42, 330A is a top view of calibration standard 420 as seen from the Z direction, and 330B is a cross-sectional view of 330A taken along line 42-42.

[0216] As shown in FIG. 42, calibration standard 420 has a generally cylindrical shape consisting of upper surface 420A, lower surface 420B, and side surface 420C.

[0217] The side surface 420C is composed of a cylindrical surface 420C1 with a radius r1 and a flat surface 420C2 continuous with the cylindrical surface 420C1. The radius r1 is an example of the "first radius". The flat surface 420C2 is a flat surface cut off from the cylindrical surface 420C1 by an amount x and is a plane parallel to the axis 420D of the cylindrical surface 420C1. The upper surface 420A and the lower surface 420B are each planes perpendicular to the axis 420D of the cylindrical surface 420C1. The upper surface 420A is an example of the "first end face", and the lower surface 420B is an example of the "second end face".

[0218] The calibration standard 420 has a fine hole 422 for image alignment and a light guide hole 424 that are each coaxial with the axis 420D. The fine hole 422 for image alignment has a radius of r2 and has a length d1 from the opening 422A on the upper surface 420A of the calibration standard 420 to the end 422B toward the lower surface 420B. The fine hole 422 for image alignment is an example of the "calibration fine hole".

[0219] Also, the light guide hole 424 has a radius of r3 and has a length d2 from the opening 424A on the lower surface 420B of the calibration standard 420 to the end 424B toward the upper surface 420A. The fine hole 422 for image alignment and the light guide hole 424 communicate at the ends 422B and 424B. The radii and lengths of the fine hole 422 for image alignment and the light guide hole 424 have the relationship of r2 < r3 and d1 < d2.

[0220] <Magnification calibration> When measuring the inner surface shape (such as roundness) of the fine hole H of the workpiece W in the inner surface shape measuring machine 400, it is necessary to perform magnification calibration of the probe 130. Therefore, in this embodiment, magnification calibration of the probe 130 is performed before starting the measurement of the inner surface shape of the fine hole H of the workpiece W.

[0221] Fig. 43 is a flowchart showing an example of the process of the magnification calibration method. The same parts as those in the flowcharts shown in Fig. 4 and Fig. 23 are given the same reference numerals, and detailed explanations will be omitted. The magnification calibration method is realized by the CPU of the control device 410 reading out a magnification calibration program from the ROM and executing it. The magnification calibration program may be provided to the inner surface shape measuring instrument 400 by communication.

[0222] The magnification calibration method includes a standard alignment step of aligning axis 420D of calibration standard 420 with rotation axis C using an image of image alignment fine hole 422 in calibration standard 420, and a probe alignment step of aligning probe 130 with rotation axis C. The standard alignment step corresponds to steps S1 to S14, and the probe alignment step corresponds to steps S20 to S28.

[0223] First, the user places the calibration standard 420 on the workpiece setting jig 18. The user places the calibration standard 420 with the top surface 420A, on which the image alignment fine hole 422 is provided, facing the camera 34 side.

[0224] When the calibration standard 420 is installed, the measurement control unit 52 drives a motor (not shown) in accordance with the detection results of an encoder (not shown) of the high-precision rotation mechanism 114, and moves (rotates) the high-precision rotation mechanism 114 to a position where the rotation angle is the set angle θ = 0° (step S1, an example of the "standard rotation process").

[0225] Next, the measurement control unit 52 drives a motor (not shown) of the arm 124 to move the camera 34 upward in the Z direction of the calibration standard 420. The measurement control unit 52 also drives a motor (not shown) of the carriage 122 to move the camera 34 in the Z direction, and aligns the focal position of the camera 34 with the opening 422A of the fine hole 422 for image alignment (step S2).

[0226] Next, the observation control unit 58 observes (photographs) the opening 422A of the image alignment fine hole 422 with the camera 34. Then, the position and tilt calculation unit 60 calculates the center coordinates (x, y) of the opening 422A of the image alignment fine hole 422 at the set angle θ=0°. 0U Calculate (step S3).

[0227] Furthermore, the measurement control unit 52 drives a motor (not shown) of the carriage 122 to move the camera 34 in the Z direction and aligns the focal position of the camera 34 with the end 422B, which is located at a different position in the Z direction from the opening 422A of the image alignment fine hole 422 (step S4).

[0228] Then, in the same manner as in the case of the opening 422A, the observation control unit 58 observes the end 422B of the image alignment fine hole 422 with the camera 34, and the position and inclination calculation unit 60 calculates the center coordinates (x, y) of the end 422B of the image alignment fine hole 422 at the set angle θ=0°. 0D Calculate (step S5).

[0229] When the process at the position of the set angle θ=0° is completed, the process at the position of the set angle θ=180° is performed in the same manner. That is, the measurement control unit 52 drives a motor (not shown) in response to the detection result of an encoder (not shown) of the high-precision rotation mechanism 114 to move the high-precision rotation mechanism 114 to a position where the rotation angle is the set angle θ=180° (step S6, an example of the "standard device rotation process"). In addition, the measurement control unit 52 drives a motor (not shown) of the carriage 122 to move the camera 34 in the Z direction, and aligns the focal position of the camera 34 with the opening 422A of the fine hole 422 for image alignment (step S7).

[0230] Next, the observation control unit 58 observes the opening 422A of the image alignment fine hole 422 with the camera 34. Next, the position and tilt calculation unit 60 calculates the center coordinates (x, y) of the opening 422A of the image alignment fine hole 422 at the set angle θ=180°. 180U Calculate (step S8).

[0231] Furthermore, the measurement control unit 52 drives a motor (not shown) of the carriage 122 to move the camera 34 in the Z direction, and adjusts the focal position of the camera 34 to the end 422B of the image alignment fine hole 422 (step S9). Next, the observation control unit 58 observes the end 422B of the image alignment fine hole 422 with the camera 34. Furthermore, the position and tilt calculation unit 60 calculates the center coordinates (x, y) of the end 422B of the image alignment fine hole 422 at the set angle θ=180°. 180D Calculate (step S10).

[0232] After these processes are completed, the position and tilt calculation unit 60 calculates the position and tilt of the axis 420D of the image alignment slot 422 of the calibration standard 420 relative to the rotation axis C of the high-precision rotation mechanism 114 (step S11, an example of the "standard attitude information acquisition process"). Here, the position and tilt calculation unit 60 calculates the central coordinates (x, y) of the opening 422A of the image alignment slot 422 at the set angle θ = 0°. 0U and the center coordinates (x, y) of the end 422B 0D and the central coordinates (x, y) of the opening 422A of the image alignment slot 422 at the set angle θ=180°. 180U and the center coordinates (x, y) of the end 422B 180D From this, the position and inclination of axis 420D relative to rotation axis C are calculated.

[0233] Next, the position and tilt calculation section 60 determines whether the position and tilt of the axis 420D of the image alignment fine hole 422 of the calibration standard 420 and the deviation between the rotation axis C are within target values ​​(step S12).

[0234] If it is determined that the deviation is greater than the target value (No in step S12), the position / inclination calculation unit 60 calculates the amount of movement of the linear motion tilt stage 118 (step S13). The calculation of the amount of movement may be performed in the same manner as in the first embodiment. The output unit 63 acquires the amount of movement of the linear motion tilt stage 118 calculated by the position / inclination calculation unit 60, and outputs it to the stage control unit 62.

[0235] Furthermore, the stage control unit 62 drives a motor (not shown) of the linear motion tilt stage 118 based on the amount of movement calculated in step S13 to move the linear motion tilt stage 118 to the target position (step S14, an example of a "standard device attitude control process"). Thereafter, the process proceeds to step S1, and the control device 50 performs the same process. By repeating this process, the inner surface shape measuring instrument 400 keeps the deviation between the axis 420D of the image alignment fine hole 422 of the calibration standard device 420 and the rotation axis C of the high-precision rotation mechanism 114 within the target value.

[0236] On the other hand, if it is determined that the deviation is smaller than the target value (Yes in step S12), the standard alignment process is terminated and the process proceeds to the probe alignment process.

[0237] When probe alignment is started, first, the imaging control unit 154 controls the high-precision rotation mechanism 114 to rotate the camera 132 together with the rotating body 116 around the rotation axis C (step S20).

[0238] Then, when the camera 132 moves to a predetermined photographing position on the rotational orbit K of the camera 132 centered on the rotational axis C, the camera 132 photographs the probe 130 at that photographing position (step S22).

[0239] It is determined whether or not imaging at all imaging positions has been completed (step S24), and when it is determined that imaging of the probe 130 by the camera 132 at all imaging positions has been completed (Yes in step S24), the relative deviation detection unit 156 detects the relative deviation between the probe 130 and the rotation axis C, which is probe attitude information, based on the captured images captured by the camera 132 at each imaging position (step S26, an example of a "probe attitude information acquisition process"). The relative deviation detected here is an example of "probe attitude information indicating the relative position of the probe axis with respect to the rotation axis."

[0240] The probe attitude control unit 158 ​​controls the probe linear motion tilt mechanism 128 based on the result detected by the relative deviation detection unit 156, and causes the central axis 130E of the probe 130 to coincide with the rotation axis C (step S28, an example of a "probe attitude control step").

[0241] When the probe 130 and the rotation axis C coincide in step S28, the measurement control unit 52 moves the probe 130 to a calibration measurement position based on the radius of the cylindrical surface 420C1 of the calibration standard 420 (step S30, an example of a "probe movement step"). That is, the measurement control unit 52 drives a motor (not shown) of the arm 124 to move the probe 130 in the -X direction, and then drives a motor (not shown) of the carriage 22 to move the probe 130 in the -Z direction. Figure 44 is a diagram showing the movement of the probe 130 in step S30. The amount of movement A of the probe 130 in the -X direction X can be expressed by the following Equation 5.

[0242] A X =r1+r4+d w …(Formula 5) where d w is the working distance of probe 130 (the distance between probe 130 and calibration standard device 420 during measurement). That is, measurement control unit 52 moves probe 130 in the -X direction from rotation axis C to a position away by the sum of the radius of cylindrical surface 420C1 of calibration standard device 420, the radius of probe 130, and the working distance of probe 130.

[0243] 43, finally, the displacement acquisition unit 54 measures the cylindrical surface 420C1 and the flat surface 420C2 of the calibration standard 420 detected by the displacement detector 28, and performs magnification calibration (step S32, an example of a "standard detection process"). With this, this flowchart ends.

[0244] According to this embodiment, by aligning the calibration standard 420 with the rotation axis C and also aligning the probe 130 with the rotation axis C, it becomes possible to calculate the movement amount when moving the probe 130 to the calibration measurement position. Therefore, there is no risk of damaging the probe 130 due to contact between the calibration standard 420 and the calibration standard 420, and it becomes possible to perform magnification calibration without relying on the skill of the operator.

[0245] Furthermore, according to this embodiment, all steps are composed of image processing and movement by a specified amount, so visual confirmation is not necessary and the calibration work can be automated, and the magnification calibration of the probe can be performed simply and reliably without being dependent on the skill of the operator. FIG. 45 shows an angle θ between the probe 130 and the rotation axis C (Z direction). P When the calibrated cutting amount between the cylindrical surface 420C1 and the flat surface 420C2 is G0 and the measured cutting amount is G1, the magnification calibration error can be expressed by the following formula 6.

[0246] Magnification calibration error=G0 / G1=cosθ P …(Formula 6) According to this embodiment, the probe 130 is moved in parallel after the probe 130 is aligned with the rotation axis C. This makes it possible to maintain the parallelism of the probe 130 with the rotation axis C and reduce the magnification calibration error caused by the installation angle of the probe 130 expressed by Equation 6. This makes it possible to easily and reliably calibrate the magnification of the probe, regardless of the skill of the operator.

[0247] <Modification> The probe alignment process is not limited to the example using the camera 132, and other methods may be used as long as the probe 130 can be aligned with the rotation axis C.

[0248] In the eighth embodiment, a case where a non-contact type probe 130 is used has been described, but the magnification calibration of the present invention can also be applied to a contact type probe 130. When a contact type probe 130 is applied, in step S30 of FIG. 43, the measurement control unit 52 drives a motor (not shown) of the arm 124 to move the probe 130 by a movement amount A expressed by Equation 5. X Then, a motor (not shown) of the carriage 22 is driven to move the probe 130 in the -Z direction, and a motor (not shown) of the arm 124 is driven to move the probe 130 by a movement amount d w In this way, the probe 130 is brought into contact with the cylindrical surface 420C1 of the calibration standard 420, and the process can proceed appropriately to step S32 in Fig. 43. Therefore, the magnification calibration of the probe can be performed simply and reliably, regardless of the skill of the operator.

[0249] Furthermore, a light source may be disposed on the side of lower surface 420B of calibration standard 420, and a light guiding mechanism may be provided that causes observation light to enter through opening 424A of light guiding hole 424.

[0250] Fig. 46 is a schematic diagram showing a part of an inner surface shape measuring machine 400A having a light guiding mechanism. In the example shown in Fig. 46, the inner surface shape measuring machine 400A includes a pedestal 430 and a light source 432. The pedestal 430 is placed on the upper surface of the workpiece setting jig 18 (see Fig. 40), and the workpiece W is placed on the upper surface of the pedestal 430. The pedestal 430 has a through hole 430A having a diameter larger than the light guiding hole 424. The light source 432 is provided in the workpiece setting jig 18, and causes observation light to be incident on an opening 424A of the light guiding hole 424 via the through hole 430A.

[0251] The light source 432 is preferably a low coherence light source in order to reduce speckle noise. For example, an LED or an ASE light source can be used as the light source 432. It is more preferable that the center of the light source 432 coincides with the rotation axis C of the high-precision rotation mechanism 114. The base 430 may be configured as a workpiece setting jig 18 including the light source 432.

[0252] According to the inner surface shape measuring device 400A, the observation light emitted from the light source 432 is made incident on the light guiding hole 424 from the lower surface 420B side of the calibration standard 420 (an example of an "incident process"), which makes it easier for the camera 34 to observe the end 422B of the image alignment fine hole 422, thereby enabling high-precision alignment of the calibration standard 420.

[0253] Note that a reflector (not shown) may be disposed in place of light source 432, and the irradiated light that enters through image alignment fine hole 422 and passes through light guiding hole 424 may be reflected by the reflector and made to re-enter from end 422B of image alignment fine hole 422. Even in this configuration, it becomes easy for camera 34 to observe end 422B of image alignment fine hole 422, so that highly accurate alignment of calibration standard 420 is possible.

[0254] Moreover, it is preferable that the measurement for magnification calibration is performed in an area within the Z direction range observed in the standard alignment step of the calibration standard 420 .

[0255] Fig. 47 is a diagram showing measurement of calibration standard 420 during magnification calibration. In Fig. 47, 340A shows a case where rotation axis C and axis 420D of calibration standard 420 coincide, and 340B shows a case where there is a misalignment between rotation axis C and axis 420D of calibration standard 420.

[0256] Image alignment slot 422 has length d1 from top surface 420A of calibration standard 420. That is, in the standard alignment step, alignment is performed using a range of length d1 from top surface 420A of calibration standard 420.

[0257] Therefore, in this case, it is preferable to measure calibration standard 420 during magnification calibration in a range of length d1 from top surface 420A of calibration standard 420. In an area within the range of length d1 from top surface 420A, the concentricity between cylindrical surface 420C1 and rotation axis C can be increased, and magnification calibration can be performed with higher accuracy, so that magnification calibration of the probe can be performed easily and reliably without being influenced by the skill of the operator.

[0258] On the other hand, if measurements are performed using an area beyond the range of length d1 from top surface 420A, the concentricity between cylindrical surface 420C1 and the rotation axis deteriorates, and the influence of the misalignment between axis 420D of calibration standard 420 and rotation axis C becomes greater.

[0259] Furthermore, calibration standard 420 may have image alignment slot 422 as a blind hole having a bottom wall. Fig. 48 shows calibration standard 420E in which image alignment slot 422 is a blind hole. In Fig. 48, 350A is a top view of calibration standard 420E as seen from the Z direction, and 350B is a 48-48 cross-sectional view of 350A.

[0260] The outer shape of calibration standard 420E is similar to that of calibration standard 420. Also similar to calibration standard 420, image alignment slot 422 of calibration standard 420E is coaxial with axis 420D and has a radius r2. Here, image alignment slot 422 is a blind hole having length d1 from opening 422A in upper surface 420A of calibration standard 420 toward lower surface 420B to end 422B, where end 422B is a plane perpendicular to axis 420D.

[0261] In this way, even if the image alignment fine hole 422 is a blind hole, the end 422B can be observed by the coaxial epi-illumination optical system 35 of the camera 34, so that the magnification calibration of the probe can be easily and reliably performed without being influenced by the skill of the operator. Note that it is preferable to make the image alignment fine hole 422 a through hole by the light guiding hole 424 as in the calibration standard 420, and to make the observation light incident from the lower surface 420B side, since this allows the end 422B to be observed more clearly.

[0262] Although the embodiment of the present invention has been described above, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the spirit of the present invention. [Explanation of symbols]

[0263] 10…Inner surface shape measuring machine 12…Main body base 14...Rotating body 16...Linear tilt stage 18...Workpiece installation jig 20…Column (support) 20. Column 22…Carriage 24…Arm 28...Displacement detector 30…Probe 34…Camera 35…Coaxial epi-illumination optical system 38...Optical fiber 40…Reflective mirror 42...Contact 50...Control device 52...Measurement control section 54...Displacement acquisition section 56...Circularity calculation section 58...Observation control section 60…Position slope calculation section 62...Stage control section 63...Output section 70...Light source 72...Reflector 80...Sponge-like reflector 82...Clay-like reflector 84...Scatterer 100A…First image 100B…Second captured image 100C…Third image 100D…4th image 102A…First composite image 102B…Second composite image 110…Inner surface shape measuring machine 110A…Inner surface shape measuring machine 110B…Inner surface shape measuring machine 112…Main body base 114…High-precision rotation mechanism 116...Rotating body 118...Linear tilt stage 120…Column 122…Carriage 124…Arm 126...Displacement detector 128... Probe linear tilt mechanism 130…Probe 130A…Probe 130B…Probe 130C…Probe 130D…Probe 130E…Center axis 132...Camera 134…Camera bracket 136…Lighting equipment 138…Lighting device bracket 150...Control device 152...Probe alignment control section 154...imaging control unit 156…Detection unit 158... Probe attitude control unit 170...Line sensor camera 172...Line sensor camera 174…Lighting equipment 176...Line laser light source 178...Line laser light source 180...Optical distance sensor 182...Optical distance sensor 210…block gauge 210A…Measuring surface 210B…Measurement surface 212...Screw-type magnification calibrator 212A…Measurement surface 214…Calibration standard 214A...Cylindrical surface 214B…Plane 400…Inner surface shape measuring machine 400A…Inner surface shape measuring machine 410...Control device 412…Inner surface shape measuring section 414…Standard alignment control section 420…Calibration standard 420A…Top surface 420B…Bottom surface 420C…side 420C1...Cylindrical surface 420C2…Plane 420D…Axis 420E…Calibration standard 422…Image alignment hole 422A…Opening 422B...End part 424…Light guide hole 424A…Opening 424B...end 430…Pedestal 430A…Through hole 432...Light source A C …optical axis A H ...center axis A R …Rotation axis C…Rotation axis C1: Probe central axis C2: Probe central axis C3: Probe central axis C4: Probe central axis F D …focal plane F U …focal plane H...Small hole I 0D …image I 0U …image I 180D …image I 180U …image K...Rotation orbit O D …Lower opening O U …Upper opening P…light path R…Shooting range S1 to S34: Each step of the magnification calibration method W…Work

Claims

1. A method for calibrating the magnification of an inner surface shape measuring machine that measures the inner surface shape of a small hole formed in a workpiece, the inner surface shape measuring machine comprising: a workpiece rotating means that rotates the workpiece about a rotation axis parallel to a first direction; and a probe having an elongated shape that can be inserted into the small hole, the probe detecting the inner surface shape of the small hole, a standard rotating step of rotating a calibration standard around the rotation axis by the work rotating means, the calibration standard having a cylindrical surface of a first radius on a side surface, a flat surface parallel to the axis of the cylindrical surface and a distance from the axis of the cylindrical surface smaller than the first radius, and a calibration slot coaxial with the cylindrical surface on a first end surface perpendicular to the axis of the cylindrical surface; a standard-device attitude information acquisition step of observing the position of the calibration narrow hole of the calibration standard device rotated in the standard-device rotation step with a first camera having an optical axis parallel to the first direction, and acquiring attitude information of the calibration standard device; a standard-unit attitude control step of aligning the axis of the calibration slot with the rotation axis based on the attitude information of the calibration standard unit acquired in the standard-unit attitude information acquisition step; a probe attitude information acquiring step of acquiring probe attitude information indicating a relative position of the axis of the probe with respect to the rotation axis; a probe attitude control step of aligning an axis of the probe with the rotation axis based on the probe attitude information acquired in the probe attitude information acquisition step; a probe moving step of moving the probe, the axis of which is aligned with the rotation axis in the probe attitude control step, in a second direction perpendicular to the first direction based on the first radius; a standard detection step of rotating the calibration standard, the axis of which is coincident with the rotation axis in the standard attitude control step, by the work rotation means, and detecting the cylindrical surface and the flat surface with the probe moved in the probe movement step; A method for calibrating the magnification of an inner surface shape measuring machine having the above-mentioned structure.

2. the probe is a non-contact probe having a second radius in the second direction; 2. The method for calibrating the magnification of an inner surface shape measuring machine according to claim 1, wherein the probe moving step moves the probe in the second direction from the position of the rotation axis to a position that is a distance equal to the sum of the first radius, the second radius, and a working distance of the probe.

3. The standard instrument attitude information acquisition step includes: an observation control process for observing, by the first camera, a first position of the calibration narrow hole of the calibration standard at a first rotation angle of the work rotation means and a second position different in the first direction from the first position, and the first position and the second position of the calibration narrow hole of the calibration standard at a second rotation angle different from the first rotation angle of the work rotation means; a position and inclination calculation step of calculating a position and an inclination of the calibration slot from respective coordinates of the first position and the second position of the calibration slot at the first rotation angle of the observed workpiece rotation means and the first position and the second position of the calibration slot at the second rotation angle of the workpiece rotation means; an output step of outputting the calculated fine hole information including the position and inclination of the fine hole as attitude information of the calibration standard; 3. The method for calibrating a magnification of an inner surface shape measuring machine according to claim 1 or 2, further comprising:

4. 4. The method for calibrating the magnification of an inner surface shape measuring machine according to claim 3, wherein the standard detection step detects a position between the first position and the second position in the first direction of the side surface by the probe.

5. 5. The method for calibrating the magnification of an inner surface shape measuring machine according to claim 1, wherein the probe attitude information acquisition step acquires the probe attitude information from at least three circumferential positions on a rotational orbit centered on the rotation axis by a probe attitude information acquisition means configured to be rotatable integrally with the workpiece rotation means.

6. 6. The method for calibrating a magnification of an inner surface shape measuring machine according to claim 5, wherein the probe attitude information acquiring step acquires the probe attitude information from four circumferential positions on the rotation orbit that are shifted from each other by 90 degrees.

7. 7. The method for calibrating a magnification of an inner surface shape measuring machine according to claim 5, wherein the probe attitude information acquisition means includes a second camera that photographs the probe.

8. 8. The method for calibrating the magnification of an internal shape measuring machine according to claim 1, wherein the calibration standard has a second end face different from the first end face, the second end face being perpendicular to the axis of the cylindrical surface, the second end face being provided with a light guide hole coaxial with the cylindrical surface and communicating with the calibration narrow hole.

9. 9. The method for calibrating the magnification of an inner surface shape measuring machine according to claim 8, wherein the standard-device attitude control step includes an incidence step of causing light emitted from a light source to enter the light-guiding hole.

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