JP7617384B2 - Inner surface shape measuring machine and alignment method for the inner surface shape measuring machine - Google Patents

Description

The present invention relates to a technique for measuring the inner shape of a small hole formed in a workpiece.

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 a workpiece using such a shape measuring machine, it is necessary to align the rotation axis with the central axis of the workpiece.

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.

JP 2006-145344 A

When using a shape measuring machine such as the one described above to measure the inner shape of a fine hole in a workpiece, the relative alignment of the probe and the rotation axis (probe alignment) is important. In other words, even if the rotation axis and the central axis of the workpiece are aligned as in the above-mentioned Patent Document 1, if there is a relative misalignment between the probe and the rotation axis, there is a problem that the probe will collide with a part of the workpiece other than the fine hole when it is inserted into the fine hole in the workpiece.

This problem can be solved if an operator inserts a probe into the workpiece's small hole while checking with an observation microscope, but this requires the operator to be highly skilled. In this case, automation is difficult and there is a risk of the probe colliding with a part of the workpiece other than the small hole due to an operating error.

The present invention was made in consideration of these circumstances, and aims to provide an inner surface shape measuring machine that can perform probe alignment accurately and easily, and an alignment method for an inner surface shape measuring machine.

To achieve the above objective, the following invention is provided.

The inner surface shape measuring machine according to the first 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 workpiece, and includes a workpiece rotation means for rotating the workpiece around a rotation axis, a probe having an elongated shape that can be inserted into the fine hole in the workpiece and for detecting the inner surface shape of the fine hole, an adjustment means for adjusting the attitude of the probe, an acquisition means configured to be rotatable integrally with the workpiece rotation means and acquiring probe attitude information from at least three circumferential positions on a rotational orbit centered on the rotation axis, and a control means for adjusting the attitude of the probe by the adjustment means based on the probe attitude information acquired by the acquisition means.

According to a second aspect of the present invention, in the first aspect, the control means adjusts the attitude of the probe by the adjustment means so that there is no relative deviation between the probe and the rotation axis.

In the third aspect of the present invention, the inner surface shape measuring machine is the first or second aspect, in which the acquisition means acquires probe attitude information from four circumferential positions that are shifted from each other by 90 degrees on the rotation orbit.

The fourth aspect of the present invention is an inner surface shape measuring machine according to any one of the first to third aspects, in which the acquisition means includes a camera that photographs the probe.

The fifth aspect of the present invention relates to an inner surface shape measuring machine according to the fourth aspect, which further includes a surface-emitting illumination means that is configured to be rotatable integrally with the workpiece rotation means and is capable of emitting surface light toward the probe from a position facing the camera.

The alignment method for an inner surface shape measuring machine according to a sixth aspect of the present invention is an alignment method for 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 a workpiece rotation means for rotating the workpiece around a rotation axis, and a probe having an elongated shape that can be inserted into the fine hole in the workpiece and that detects the inner surface shape of the fine hole, the alignment method for an inner surface shape measuring machine comprising an acquisition step of acquiring probe attitude information from at least three circumferential positions on a rotational orbit centered on the rotation axis, and an adjustment step of adjusting the attitude of the probe based on the probe attitude information acquired in the acquisition step so that the probe is coaxial with the rotation axis.

The alignment method for an inner surface shape measuring machine according to the seventh aspect of the present invention is the sixth aspect, in which the pre-acquisition step acquires probe attitude information from four circumferential positions that are shifted from each other by 90 degrees on the rotational orbit.

The present invention allows probe alignment to be performed easily and accurately.

1 is a schematic diagram showing an overall configuration of an inner surface shape measuring machine according to a first embodiment. FIG. FIG. 2 is a block diagram showing a configuration of a control device. 11 is a flowchart showing an example of a flow of probe alignment. FIG. 13 is a diagram showing an example of a position where a probe is photographed by a camera. 1A to 1C are explanatory diagrams showing examples of images captured by a camera at each shooting position. FIG. 13 is a diagram showing a composite image of the first captured image and the third captured image. FIG. 13 is a diagram showing a composite image of the second captured image and the fourth captured image. 13 is a diagram showing another example of the position at which the probe is photographed by the camera. FIG. FIG. 13 is a diagram showing yet another example of the position at which the probe is photographed by the camera. FIG. 11 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine according to a second embodiment. FIG. 11 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine according to a third embodiment. FIG. 13 is a schematic diagram showing a configuration of a main part of an inner surface shape measuring machine according to a fourth embodiment. 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. 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. FIG. 13 is a diagram for explaining an application example of the present invention. FIG. 13 is a diagram for explaining an application example of the present invention.

A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[First embodiment]
<Configuration of inner surface shape measuring machine>
Fig. 1 is a schematic diagram showing the overall configuration of an inner surface shape measuring machine 10 of 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 through 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.

As shown in FIG. 1, the inner surface shape measuring device 10 includes a main body base 12, a high-precision rotation mechanism 14, a linear tilt stage 18, a column 20, a carriage 22, an arm 24, a displacement detector 26, a probe linear tilt mechanism 28, a camera 32, and a control device 50.

The high-precision rotation mechanism 14 is a rotation mechanism for rotating the workpiece W around the rotation axis C, and rotates the linear tilt stage 18 (described later) with high precision around the rotation axis C parallel to the Z direction. The high-precision rotation mechanism 14 includes a rotor 16 rotatably mounted on the main body base 12, and the linear tilt stage 18 is supported on the upper surface of the rotor 16. The high-precision rotation mechanism 14 includes a motor (not shown) that rotates the rotor 16 with high precision around the rotation axis C, and an encoder (not shown) that detects the rotation angle of the rotor 16.

The linear tilt stage 18 is used to place the workpiece W. The linear tilt stage 18 may directly support and fix the workpiece W, or may support and fix the workpiece W via a workpiece installation jig (not shown).

The linear tilt stage 18 is supported on the support surface (upper surface) of the rotating body 16, and is configured to be rotatable integrally with the rotating body 16 around the rotation axis C. As a result, the workpiece W supported and fixed to the linear tilt stage 18 can be rotated integrally with the linear tilt stage 18 around the rotation axis C. The linear tilt stage 18 and the rotating body 16 are an example of a "workpiece rotation means."

The linear tilt stage 18 is equipped with a linear mechanism (centering mechanism) and a tilting mechanism (tilting mechanism) (both not shown). The linear mechanism moves the linear tilt stage 18 in the X and Y directions by driving a motor (not shown) to adjust the position of the linear tilt stage 18 in the XY plane (horizontal plane) perpendicular to the rotation axis C. The tilting mechanism rotates the linear tilt stage 18 around the X and Y directions by driving a motor (not shown) to adjust the tilt of the linear tilt stage 18 relative to the XY plane. Therefore, by adjusting the position and tilt of the linear tilt stage 18 in the horizontal direction (X and Y directions) by the linear mechanism and the tilting mechanism, it is possible to perform eccentricity correction (centering adjustment) and tilt correction (tilting adjustment) of the central axis of the workpiece W relative to the rotation axis C.

A column (support) 20 extending parallel to the Z direction is erected on the main body base 12. The lower end of the column 20 is fixed to the upper surface of the main body base 12.

The carriage 22 is supported by the column 20 so as to be movable in the Z direction. The carriage 22 is configured to be movable in the Z direction by being driven by a motor (not shown).

The arm 24 is supported by the carriage 22 so as to be movable in the X direction. The arm 24 is configured to be movable in the X direction by being driven by a motor (not shown).

The displacement detector 26 is supported by the arm 24 via a probe linear motion tilt mechanism 28. The displacement detector 26 has an elongated probe 30 that can be inserted into the small hole H of the workpiece W. The probe 30 detects the shape of the inner surface (measurement surface) of the small hole H of the workpiece W in a state where it is 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 30.

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.

The probe 30 is not limited to a non-contact probe, but may be a contact probe. A 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, or a thin film distortion measurement method may be used. In addition, a method may be used in which the contactor of the contact probe is vibrated at a resonant frequency and the resonance point changes due to contact.

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 extremely small diameter holes H, as in this embodiment.

The probe linear tilt mechanism 28 is provided between the arm 24 and the displacement detector 26. The probe linear tilt mechanism 28 includes a linear mechanism and a tilt mechanism (both not shown). The linear mechanism moves the displacement detector 26 in the X and Y directions by driving a motor (not shown) to adjust the position of the probe 30 in the XY plane (horizontal plane) perpendicular to the rotation axis C. The tilt mechanism rotates the displacement detector 26 around the X and Y directions by driving a motor (not shown) to adjust the tilt of the probe 30 relative to the XY plane. Therefore, by adjusting the position and tilt of the probe 30 in the horizontal direction (X and Y directions) by the probe linear tilt mechanism 28 (linear mechanism and tilt mechanism), it is possible to perform relative alignment (probe alignment) between the probe 30 and the rotation axis C. The probe linear tilt mechanism 28 is an example of an "adjustment means". Note that the probe alignment, which is a feature of the present invention, will be described later.

The camera 32 is an area sensor camera (two-dimensional sensor camera) such as a CCD (Charge Coupled Device) camera. The camera 32 is connected (supported) to the rotating body 16 via a camera bracket 34. The camera 32 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 32 is adjusted to match the rotation axis C. As a result, the camera 32 can rotate around the rotation axis C together with the rotating body 16, and the camera 32 can capture an image of the probe 30 at any shooting position (circumferential position) on a rotational orbit K centered on the rotation axis C (see FIG. 4). Note that a known method such as a slip ring or wireless power supply can be applied to supply power to the camera 32. The camera 32 is an example of an "acquisition means", and the captured image captured by the camera 32 is an example of "probe attitude information".

<Control device>
The control device 50 controls the operation of each part of the inner surface shape measuring machine 10 (including the operation of measuring the inner surface shape of the workpiece W and the probe alignment operation described below). 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), and an input/output interface. In the control device 50, 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 10, and various arithmetic processing or control processing is executed via the input/output interface. The control device 50 is an example of a "control means".

Figure 2 is a block diagram showing the configuration of the control device 50. Note that in Figure 2, only the configuration related to the probe alignment operation performed by the inner surface shape measuring machine 10 is illustrated. Note that the control device 50 also has configuration related to the measurement operation of 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.

As shown in FIG. 2, the control device 50 includes a probe alignment control unit 52. The probe alignment control unit 52 is a functional unit that controls the operation for performing relative position alignment (probe alignment) between the probe 30 and the rotation axis C.

Here, the configuration of the probe alignment control unit 52 will be described in detail. The probe alignment control unit 52 includes an imaging control unit 54, a relative deviation detection unit 56, and a probe posture control unit 58.

The imaging control unit 54 controls the high-precision rotation mechanism 14 to rotate the camera 32 around the rotation axis C together with the rotor 16, thereby changing the imaging position (circumferential position) of the camera 32 relative to the probe 30 in the circumferential direction centered on the rotation axis C. This enables the camera 32 to image the probe 30 from at least three imaging positions on the rotation orbit K of the camera 32 centered on the rotation axis C. As described below, in this embodiment, the probe 30 is preferably imaged from four imaging positions that are shifted from each other by 90 degrees on the rotation orbit K of the camera 32 (see FIG. 4).

The imaging control unit 54 also controls the camera 32 that has moved to each imaging position to capture an image of the probe 30. The imaging control unit 54 causes the image captured by the camera 32 to be transmitted to the relative deviation detection unit 56.

The relative deviation detection unit 56 detects the relative deviation between the rotation axis C and the probe 30 based on the captured images acquired by the camera 32 at each capture position. A specific detection method will be explained in the probe alignment section below.

The probe posture control unit 58 controls the probe linear motion tilt mechanism 28 based on the relative deviation detected by the relative deviation detection unit 56. Specifically, the probe posture control unit 58 controls the probe linear motion tilt mechanism 28 to adjust the position and tilt of the probe 30 so that the relative deviation detected by the relative deviation detection unit 56 is eliminated, thereby aligning the probe 30 relative to the rotation axis C.

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

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 30 is moved in the Z direction together with the displacement detector 26 by the carriage 22, and the probe 30 is inserted into the fine hole H in the workpiece W. Then, with the probe 30 inserted into the fine hole H in the workpiece W, the workpiece W is rotated around the rotation axis C while the probe 30 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.

Here, in order to insert the probe 30 into the fine hole H before the measurement is started, it is necessary to adjust the attitude (position and inclination) of the probe 30 so that the probe 30 is positioned coaxially with the rotation axis C. If there is a relative misalignment between the probe 30 and the rotation axis C, when an attempt is made to insert the probe 30 into the fine hole H, the probe 30 will collide with a part of the workpiece W other than the fine hole H, making it difficult to measure the inner shape of the fine hole H.

Therefore, in this embodiment, before measurement of the inner shape of the fine hole H in the workpiece W is started, the probe 30 is aligned relative to the rotation axis C (probe alignment) so that there is no relative misalignment between the probe 30 and the rotation axis C. Note that the eccentricity correction and tilt correction (workpiece alignment) of the central axis of the workpiece W relative to the rotation axis C is performed by the linear tilt stage 18, and it is assumed that the central axis of the workpiece W is coaxial with the rotation axis C. Workpiece alignment may be performed after or before the probe alignment. Workpiece alignment is not an essential part of the present invention, so a description thereof will be omitted here.

Figure 3 is a flowchart showing an example of the probe alignment process.

As shown in FIG. 3, when probe alignment is started, the imaging control unit 54 first controls the high-precision rotation mechanism 14 to rotate the camera 32 together with the rotating body 16 around the rotation axis C (step S10). Then, when the camera 32 moves to a predetermined imaging position on the rotation orbit K of the camera 32 centered on the rotation axis C, the camera 32 images the probe 30 at that imaging position (step S12, an example of an "acquisition step").

Next, it is determined whether or not imaging has been completed at all imaging positions (step S14). If it is determined that imaging has not been completed at all imaging positions (No in step S14), the camera 32 is rotated (step S10) and the camera 32 takes images of the probe 30 (step S12) repeatedly until it is determined that imaging has been completed at all imaging positions. Note that whether or not the camera 32 has moved to each imaging position can be determined based on the output of an encoder provided in the high-precision rotation mechanism 14. Note that any configuration other than an encoder can be applied as long as it can determine whether or not the camera 32 has moved to each imaging position.

Figure 4 is a diagram showing an example of the image capturing positions of the probe 30 by the camera 32. As shown in Figure 4, in the probe alignment of this embodiment, the camera 32 is rotated about the rotation axis C by the rotational movement of the rotor 16, and the camera 32 captures the image of the probe 30 at a predetermined image capturing position (circumferential position) on the rotational orbit K of the camera 32 centered on the rotational axis C of the rotor 16. Specifically, the camera 32 captures the image of the probe 30 at four image capturing positions P1 to P4 that are shifted from each other by 90 degrees on the rotational orbit K of the camera 32 centered on the rotational axis C.

In terms of the planar (XY plane) positional relationship between 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 the two mutually orthogonal directions. The second shooting position P2 and the fourth shooting position P4 are opposed to each other in the second direction (X direction).

In this embodiment, the direction in which the camera 32 captures images of the probe 30 from the four capture positions P1 to P4 is the X direction or the Y direction, which is the same as the control direction (movement axis direction) that causes the probe 30 to move linearly or tilt in the probe linear motion tilt mechanism 28.

In this embodiment, as one preferred aspect, the first direction (Y direction) in which the first shooting position P1 and the third shooting position P3 face each other, and the second direction (X direction) in which the second shooting position P2 and the fourth shooting position P4 face each other, are consistent with the control direction of the probe linear tilt mechanism 28, but this is not necessarily limited to this aspect. For example, they may be directions different from the control direction of the probe linear tilt mechanism 28, and the first direction and the second direction do not have to be orthogonal to each other. However, this embodiment is preferable because it allows the relative deviation between the probe 30 and the rotation axis C to be simply and easily detected independently in each direction.

Returning to FIG. 3, when it is determined that the camera 32 has completed capturing images of the probe 30 at all capturing positions (Yes in step S14), the relative deviation detection unit 56 detects the relative deviation between the probe 30 and the rotation axis C based on the captured images captured by the camera 32 at each capturing position (step S16).

Now, we will explain in detail how to detect the relative misalignment between the probe 30 and the rotation axis C.

Figure 5 shows an example of images captured by the camera 32 at each of the image capturing positions P1 to P4. In Figure 5, the first captured image 100A is an image captured at the first image capturing position P1, and similarly, the second captured image 100B is an image captured at the second image capturing position P2, the third captured image 100C is an image captured at the third image capturing position P3, and the fourth captured image 100D is an image captured at the fourth image capturing position P4.

When there is a relative misalignment between the probe 30 and the rotation axis C, for example as shown in FIG. 5, the posture (position and inclination) of the probe 30 differs in the captured images 100A to 100D captured by the camera 32 at each of the capture positions P1 to P4 depending on the capture position (i.e., the capture direction of the probe 30 by the camera 32).

For example, of two photographing positions (first photographing position P1 and third photographing position P3) that face each other in the first direction (Y direction), in the first photographing image 100A taken from one photographing position (first photographing position P1), the probe 30A is tilted to one side in the second direction (X direction), whereas in the third photographing image 100C taken from the other photographing position (third photographing position P3), the probe 30C is tilted to the other side in the second direction (X direction). Also, the positions in the second direction (X direction) are shifted toward opposite sides.

The same is true for the second captured image 100B and the fourth captured image 100D at two capturing positions (second capturing position P2 and fourth capturing position P4) that face each other in the second direction (X direction), and the positions and inclinations of the probes 30B and 30D are shifted in opposite directions.

Figure 6 shows a first composite image 102A that is a composite of a first captured image 100A and a third captured image 100C captured from two opposing capture positions (first capture position P1 and third capture position P3) in the first direction (Y direction).

As shown in FIG. 6, in the first composite image 102A obtained by combining the first captured image 100A and the third captured image 100C, the first midline ML1 between the central axis (first probe central axis) L1 of the probe 30A in the first captured image 100A and the central axis (third probe central axis) L3 of the probe 30C in the third captured 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). Note that the first midline ML1 is a straight line that passes through the center of the horizontal direction (X direction) of the first probe central axis L1 and the third probe central axis L3 in the vertical direction (Z direction) in the first composite image 102A. 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.

The first midline ML1 in the first composite image 102A indicates the position of the rotation axis C. In other words, the first midline ML1 indicates a line in the first composite image 102A (in the XZ plane) that is the movement target of the probe 30, and by adjusting the attitude (position and inclination) of the probe 30 so that the probe 30 coincides with the first midline ML1, it is possible to eliminate the relative misalignment between the rotation axis C and the probe 30 in the XZ plane.

Figure 7 shows a composite image 102B obtained by combining a second captured image 100B and a fourth captured image 100D captured from two opposing capture positions (second capture position P2 and fourth capture position P4) in the second direction (X direction).

As shown in FIG. 7, in the second composite image 102B obtained by combining the second photographed image 100B and the fourth photographed image 100D, the second midline ML2 between the central axis (second probe central axis) L2 of the probe 30B in the second photographed image 100B and the central axis (fourth probe central axis) L4 of the probe 30D 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 30 is viewed from the second direction (X direction)). Note that the second midline ML2 refers to a straight line that passes 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.

The second midline ML2 in the second composite image 102B indicates the position of the rotation axis C. In other words, the second midline ML2 indicates a line that is the movement target of the probe 30 in the second composite image 102B (in the YZ plane), and by adjusting the attitude (position and inclination) of the probe 30 so that the probe 30 coincides with the second midline ML2, it is possible to eliminate the relative misalignment between the rotation axis C and the probe 30 in the YZ plane.

Therefore, by calculating the two midlines ML1 and ML2 described above based on the images captured by the camera 32 at four shooting positions P1 to P4 that are shifted by 90 degrees from each other on the rotational orbit K of the camera 32 centered on the rotational axis C, it is possible to detect the rotational axis C (center of rotation) that is the movement target of the probe 30, and it becomes possible to adjust the relative deviation between the rotational axis C and the probe 30 independently in each direction (X direction and Y direction).

In the probe alignment of this embodiment, when one of the two probes 30 in the first composite image 102A shown in FIG. 6 is used as the reference probe (in this example, the probe 30A in the first captured image 100A), the relative deviation detection unit 56 detects 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 as the tilt movement amount θ, and detects the movement distance in the X direction required to make 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 as the linear movement amount Dx. The linear movement amount Dx corresponds to the distance along the X-direction movement axis of the probe linear tilt mechanism 28 (see FIG. 6).

7, when one of the two probes 30 is set as the reference probe (in this example, the probe 30B in the second captured image 100B), the relative deviation detection unit 56 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 28 (see FIG. 7).

The relative deviation detection unit 56 can calculate the probe central axes C1 to C4, the midlines ML1 and ML2, the linear movement amounts Dx and Dy, and the tilt movement amounts θ and φ from each of the composite images 102A and 102B using known image processing such as edge extraction.

In this way, when the relative deviation detection unit 56 detects the relative deviation between the probe 30 and the rotation axis C in each direction independently based on the captured images captured by the camera 32 at each capture position (step S16), the probe attitude control unit 58 controls the probe linear tilt mechanism 28 based on the results detected by the relative deviation detection unit 56. Specifically, the probe attitude control unit 58 controls the probe linear tilt mechanism 28 to move the probe 30 by a linear movement amount Dx in the X direction and a linear movement amount Dy in the Y direction, and tilt the probe 30 by a tilt movement amount φ around the X direction and a tilt movement amount θ around the Y direction (step S18, an example of an "adjustment step"). The direction (orientation) in which the probe linear tilt mechanism 28 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. 6 or FIG. 7.

In this way, when the probe posture control unit 58 controls the probe linear tilt mechanism 28 to change the posture of the probe 30 based on the results detected by the relative deviation detection unit 56, the relative deviation between the probe 30 and the rotation axis C in three-dimensional space disappears. This is the end of this flowchart.

＜Effects＞
According to the probe alignment in this embodiment, the relative deviation between the probe 30 and the rotation axis C can be detected independently in each direction (X direction and Y direction) based on the four captured images 100A to 100D of the probe 30 captured by the camera 32 at four capture positions P1 to P4 that are shifted by 90 degrees from each other on the rotation orbit K of the camera 32 centered on the rotation axis C of the rotating body 16. This makes it possible to control the attitude (position and inclination) of the probe 30 independently in each direction by the probe linear motion tilt mechanism 28, and it becomes possible to eliminate the relative deviation between the probe 30 and the rotation axis C with higher accuracy. Therefore, even if, for example, 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 30 is a very small diameter probe with an outer diameter of about 80 μm, 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 30 colliding with parts other than the fine hole H of the work W.

In addition, according to the probe alignment of this embodiment, the camera 32, which rotates together with the rotating body 16, is used to detect the position of the rotation axis C (center of rotation), which is the target of movement of the probe 30, by relatively comparing images taken from multiple different directions. Therefore, even if the camera 32 is attached to the camera bracket 34 with a positional deviation in a predetermined direction, causing a deviation in the relative positional relationship between the camera 32 and the rotation axis C, for example, it is possible to accurately align the relative positions of the probe 30 and the rotation axis C, and precision in attaching the camera 32 is not required.

In addition, in the probe alignment of this embodiment, the relative position between the camera 32 and the probe 30 is changed in the circumferential direction around the rotation axis C to capture images. Therefore, even if the position of the rotation axis C is unclear or the rotation axis C is tilted, it is possible to perform accurate relative alignment between the probe 30 and the rotation axis C from the images captured by the camera 32 at each of the capture positions P1 to P4.

<Modification>
In the probe alignment of this embodiment, the relative misalignment between the probe 30 and the rotation axis C of the rotating body 16 is detected independently in each direction based on four captured images 100A to 100D of the probe 30 taken by the camera 32 at four shooting positions P1 to P4 shifted by 90 degrees from each other on the rotation orbit K of the camera 32 centered on the rotation axis C of the rotating body 16. However, this is not limited to this, and for example, as shown in Figure 8, the probe 30 may be captured by the camera 32 from at least three shooting positions on the rotation orbit K of the camera 32 centered on the rotation axis C of the rotating body 16.

In other words, if the relative deviation between the probe 30 and the rotation axis C can be detected independently in each direction, it is sufficient to image the probe 30 with the camera 32 from at least three directions centered on the rotation axis C. In this case, it is possible to detect the relative deviation between the probe 30 and the rotation axis C independently in each direction by relatively comparing the images captured by the camera 32 at each shooting position in relation to the position information (rotation angle, rotation radius, etc.) related to each shooting position. Then, based on the detected relative deviation, it becomes possible to control the attitude of the probe 30 independently in each direction by the probe linear tilt mechanism 28. This makes it possible to eliminate the relative deviation between the probe 30 and the rotation axis C.

Also, as shown in FIG. 9, the camera 32 may be rotated by the rotational movement of the rotor 16, while the camera 32 continuously captures images of the probe 30 at regular intervals. In this case, it becomes possible to use a large number of captured images, and therefore probe alignment can be performed with high accuracy. Also, by continuously capturing images of the probe 30 while the camera 32 is rotating, it becomes possible to limit the range in which the camera 32 rotates to a certain range, and therefore it becomes possible to perform probe alignment more efficiently in a shorter time.

In this embodiment, the camera 32 is attached to the rotating body 16 via a camera bracket 34, but this is not limiting, and any configuration can be appropriately adopted as long as the camera 32 can rotate at least around the rotation axis C that is the target for alignment with the probe 30.

[Second embodiment]
10 is a schematic diagram showing the configuration of an inner surface shape measuring machine 10A of the second embodiment. As shown in FIG. 10, in the inner surface shape measuring machine 10A of the second embodiment, a camera 32 is attached to a linear inclined stage 18 via a camera bracket 34. The photographing direction of the camera 32 is the same as in the first embodiment described above, and faces the rotation axis C side (probe 30 side) which is the center of rotation. In addition, the focus of the camera 32 is adjusted to match the rotation axis C, and the probe 30 arranged near the rotation axis C can be photographed. In the second embodiment, the camera 32 can rotate around the rotation axis C together with the rotating body 16, and probe alignment can be performed in the same manner as in the first embodiment described above.

[Third embodiment]
Fig. 11 is a schematic diagram showing the configuration of an inner surface shape measuring machine 10B of the third embodiment. As shown in Fig. 11, the inner surface shape measuring machine 10B of the third embodiment further includes an illumination device 36 at a position facing the camera 32 across the rotation axis C, in addition to the configuration of the inner surface shape measuring machine 10 of the first embodiment.

The lighting device 36 is attached to the rotating body 16 via a lighting device bracket 38, and can rotate integrally with the rotating body 16 around the rotation axis C. The lighting device 36 is a surface-emitting lighting device capable of emitting light from a surface. The lighting device 36 is an example of a "surface-emitting lighting means."

According to the third embodiment, when the camera 32 photographs the probe 30 while rotating around the rotation axis C integrally with the rotating body 16, the illumination device 36 rotates around the rotation axis C integrally with the rotating body 16 at a position facing the camera 32. Therefore, the camera 32 photographs the probe 30 while maintaining the relative positional relationship between the camera 32 and the illumination device 36, so that it is possible to photograph the probe 30 under the same illumination conditions regardless of the photographing position of the camera 32. 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. Note that the illumination device 36 is preferably a surface-emitting illumination, but is not necessarily limited to surface-emitting illumination.

The third embodiment is not limited to the first embodiment, but can also be applied to the second embodiment.

[Fourth embodiment]
Fig. 12 is a schematic diagram showing the main configuration of the inner surface shape measuring machine of the fourth embodiment. In Fig. 12, 200A, 200B, and 200C are a front view of the probe 30 and the two line sensor cameras 70 and 72 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.

In each of the above-mentioned embodiments, an area sensor camera was used as the camera 32, but the fourth embodiment is different in that two line sensor cameras (one-dimensional sensor cameras) 70, 72 are used.

As shown in FIG. 12, the two line sensor cameras 70, 72 are cameras that capture images of a linear (line-shaped) area extending in a horizontal direction perpendicular to the Z direction (Y direction in FIG. 12). The two line sensor cameras 70, 72 are parallel to each other and arranged at a predetermined distance in the Z direction. The two line sensor cameras 70, 72 are attached to the rotating body 16 (see FIG. 1) via a line sensor camera bracket (not shown), similar to the camera 32 in the first embodiment.

In addition, an illumination device 74 is provided at a position facing the two line sensor cameras 70, 72. The probe 30 is disposed between the two line sensor cameras 70, 72 and the illumination device 74. As in the third embodiment, the illumination device 74 is attached to the rotating body 16 (see FIG. 1) via an illumination device bracket (not shown). In addition, an illumination device capable of surface emission is preferably used as the illumination device 74, but is not necessarily limited to surface emission.

In the fourth embodiment, the camera 32 is rotated around the rotation axis C together with the rotating body 16, and the probe 30 is photographed by the two line sensor cameras 70, 72 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 70, 72 at each photographing position, it is possible to calculate the position of the probe 30 in the photographing area of each line sensor camera 70, 72. Therefore, by combining the photographed images taken by the two line sensor cameras 70, 72 at each photographing position, information (probe attitude information) equivalent to the image taken by the camera 32 in the first embodiment can be obtained, and the relative deviation between the probe 30 and the rotation axis C can be detected. Therefore, as in the first embodiment, it is possible to perform probe alignment with high accuracy.

In the fourth embodiment, similarly to the third embodiment, two line sensor cameras 7
An illumination device 74 is provided at a position facing the line sensor cameras 70, 72, and the two line sensor cameras 70, 72 and the illumination device 74 are configured to be rotatable around the rotation axis C integrally with the rotating body 16 with the probe 30 disposed between the two line sensor cameras 70, 72 and the illumination device 74. Therefore, since the probe 30 is photographed by the two line sensor cameras 70, 72 with the relative positional relationship between the two line sensor cameras 70, 72 and the illumination device 74 maintained, it is possible to photograph the probe 30 under the same illumination conditions regardless of the photographing positions of the two line sensor cameras 70, 72. 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.

[Fifth embodiment]
Fig. 13 is a schematic diagram showing the main configuration of the inner surface shape measuring machine of the fifth embodiment. In Fig. 13, 300A, 300B, and 300C are a front view of the probe 30 and the two line sensor cameras 70 and 72 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.

In the fourth embodiment, the lighting device 74 (see FIG. 12) was provided in a position facing the two line sensor cameras 70 and 72, whereas in the fifth embodiment, the line laser light sources 76 and 78 are provided above the line sensor cameras 70 and 72, respectively.

The line laser light sources 76, 78 irradiate the line-shaped imaging areas of the corresponding line sensor cameras 70, 72 with line lasers (line-shaped laser beams) R1, R2. The line laser light sources 76, 78 are attached to the rotating body 16 (see FIG. 1) together with the line sensor cameras 70, 72 via a line sensor camera bracket (not shown), and can rotate integrally with the rotating body 16 around the rotation axis C.

In the fifth embodiment, similar to the fourth embodiment, by combining the images captured by the two line sensor cameras 70 and 72 at each shooting position, information (probe attitude information) equivalent to the image captured by the camera 32 in the first embodiment can be obtained, and the relative deviation between the probe 30 and the rotation axis C can be detected. Therefore, similar to the first embodiment, it is possible to perform probe alignment easily and with high accuracy.

In addition, in the fifth embodiment, the probe 30 is photographed by the two line sensor cameras 70, 72 while maintaining the relative positional relationship between the two line sensor cameras 70, 72 and the two line laser light sources 76, 78, so it is possible to photograph the probe 30 under the same lighting conditions regardless of the photographing positions of the two line sensor cameras 70, 72.

Note that FIG. 13 shows an example of a configuration in which two line laser light sources 76, 78 are arranged above each line sensor camera 70, 72, but the positions at which the two line laser light sources 76, 78 are arranged are not particularly limited as long as they can irradiate the imaging areas of each line sensor camera 70, 72 with line lasers.

Sixth Embodiment
Fig. 14 is a schematic diagram showing the main configuration of the inner surface shape measuring machine of the sixth embodiment. Fig. 14 is a front view of the probe 30 and the two optical distance measuring sensors 80, 82 as viewed from the Y direction.

In each of the above embodiments, an imaging device (area sensor camera or line sensor camera) that images the probe 30 from each imaging position is used as an acquisition means for acquiring probe posture information to detect the relative deviation between the probe 30 and the rotation axis C, whereas in the sixth embodiment, two optical distance measuring sensors 80, 82 that measure distance using light are used.

As shown in FIG. 14, the two optical distance measuring sensors 80, 82 are arranged at a predetermined interval in the Z direction and are attached to the rotating body 16 via a bracket (not shown). The two optical distance measuring sensors 80, 82 measure distance by emitting light and detecting the reflected light. The two optical distance measuring sensors 80, 82 are sensors whose detection principle is triangulation, and for example, PSD (Position Sensitive Detector), CMOS (Complementary Metal-Oxide Semiconductor), or CCD (Charge Coupled Device) types can be applied. Note that the detection principle of the triangulation method is publicly known, so a description thereof will be omitted here.

According to the sixth embodiment, the two optical distance measuring sensors 80, 82 are rotated around the rotation axis C integrally with the rotating body 16, and the two optical distance measuring sensors 80, 82 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 80, 82 at each measurement position and each measurement position, information equivalent to the image captured by the camera 32 in the first embodiment (probe attitude information) can be obtained, and the relative deviation between the probe 30 and the rotation axis C can be detected. Therefore, as in the first embodiment, it is possible to perform probe alignment accurately and easily.

In the sixth embodiment, the acquisition means for acquiring probe posture information for detecting the relative deviation between the probe 30 and the rotation axis C is shown as an example using two optical distance measuring sensors 80, 82 as an example other than an imaging device (area sensor camera or line sensor camera). However, any other means may be used as long as it is capable of acquiring probe posture information for detecting the relative deviation between the probe 30 and the rotation axis C. For example, a laser type, LED (Light Emitting Diode) type, ultrasonic type, or eddy current type length measuring sensor may be used.

[Application example]
According to each of the above embodiments, the attitude (position and inclination) of the probe 30 with respect to the rotation axis C can be detected. Therefore, not only can the probe 30 be aligned with the rotation axis C, but the probe 30 can also be adjusted to a position tilted by a required angle. For example, as shown in FIG. 15, 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 30) to match 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 30 is irradiated from a normal direction perpendicular to the tapered surface (measurement surface), making it possible to perform measurement with higher sensitivity and accuracy. In addition, as shown in FIG. 16, it is also possible to accurately calculate the difference in the measurement target position due to the attitude of the probe 30.

Although the embodiments of the present invention have 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.

10... inner surface shape measuring device, 12... main body base, 14... high-precision rotation mechanism, 16... rotating body, 18... linear motion tilt stage, 20... column, 22... carriage, 24... arm, 26... displacement detector, 28... probe linear motion tilt mechanism, 30... probe, 32... camera, 34... camera bracket, 36... lighting device, 38... lighting device bracket, 50... control device, 52... probe alignment control unit, 54... photography control unit, 56... relative deviation detection unit, 58 ... Probe attitude control unit, 70, 72... Line sensor camera, 74... Illumination device, 76, 78... Line laser light source, 80, 82... Optical distance measurement sensor, 100A... First captured image, 100B... Second captured image, 100C... Third captured image, 100D... Fourth captured image, 102A... First composite image, 102B... Second composite image, W... Workpiece, P1... First captured position, P2... Second captured position, P3... Third captured position, P4... Fourth captured position, C... Rotation axis, K... Rotation orbit

Claims (7)

An inner surface shape measuring machine for measuring the inner surface shape of a small hole formed in a workpiece,
A workpiece rotating means for rotating the workpiece around a rotation axis;
a probe having an elongated shape that can be inserted into the small hole and that detects the inner shape of the small hole;
an adjustment means for adjusting the attitude of the probe;
an acquiring means configured to be rotatable integrally with the work rotating means, and configured to acquire probe attitude information from at least three circumferential positions on a rotational orbit centered on the rotation axis;
a control means for adjusting the attitude of the probe by the adjustment means based on the probe attitude information acquired by the acquisition means;
An inner surface shape measuring machine equipped with the control means adjusts the attitude of the probe by the adjustment means so as to eliminate any relative deviation between the probe and the rotation axis.
The inner surface shape measuring machine according to claim 1. the acquiring means acquires the probe attitude information from four circumferential positions that are shifted from each other by 90 degrees on the rotation orbit.
3. The inner surface shape measuring machine according to claim 1 or 2. The acquisition means includes a camera that captures an image of the probe.
The inner surface shape measuring machine according to any one of claims 1 to 3. The workpiece rotating means is configured to be rotatable integrally with the workpiece rotating means, and further includes a surface-emitting illumination means capable of emitting surface light from a position facing the camera toward the probe.
The inner surface shape measuring machine according to claim 4. An alignment method for an inner surface shape measuring machine that measures an 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; and a probe having an elongated shape that can be inserted into the small hole and that detects the inner surface shape of the small hole,
an acquiring step in which the acquiring means acquires probe attitude information from at least three circumferential positions on a rotation orbit centered on the rotation axis of the acquiring means, the acquisition means being rotatable integrally with the workpiece rotating means ;
an adjustment step of adjusting an attitude of the probe based on the probe attitude information acquired in the acquisition step so as to eliminate a relative deviation between the probe and the rotation axis;
An alignment method for an inner surface shape measuring machine comprising: the acquiring step acquires the probe attitude information from four circumferential positions on the rotation orbit that are shifted from each other by 90 degrees,
The alignment method for an inner surface shape measuring machine according to claim 6.

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