JP4775943B2 - Inspection apparatus, inspection method, and cylinder block manufacturing method using the same - Google Patents

Description

  The present invention relates to an inspection apparatus, an inspection method, and a cylinder block manufacturing method using the inspection apparatus, and more particularly to an inspection apparatus and an inspection method for inserting and inspecting a lens barrel and a cylinder block manufacturing method using the same.

  In the development and production of automobile engines and the like, it is very important to observe, inspect and analyze the cylinder inner wall provided in the cylinder block. The inner diameter of the cylinder is very small, for example, about 30 mm, and a measurement microscope cannot be inserted. Conventionally, three-dimensional measurement has been performed by cutting a sample or taking a replica. However, the cylinder can be cut at the development stage, but the product cannot be cut by inspection in the mass production line. For this reason, there is a demand for non-destructive inspection of the inner wall of the cylinder.

  Thus, the microscope for observing an inner wall is disclosed (refer patent document 1 and patent document 2). These microscopes have a configuration in which an objective lens and a mirror are incorporated on the distal end side of the cylinder. Then, the cylinder inner wall is observed by inserting the cylinder into the cylinder. Further, an apparatus for measuring an inner diameter by turning a laser displacement meter inserted in a cylinder is disclosed (see Patent Document 3).

Furthermore, a hole inner surface inspection device is disclosed in which the in-focus position of the lens is changed and the distance between the optical center and the inner wall surface is obtained from the amount of lens displacement at the in-focus position (see Patent Document 4). Paragraph 0021 of Patent Document 4 describes that the in-focus state is detected using a differential detection method such as a beam size method, a knife edge method, an astigmatism method, or a Foucault method. Paragraph 0029 also describes that a pinhole detection method can be employed. Thereby, the internal diameter and uneven | corrugated shape of a hole can be measured with high precision.
JP-A-10-123424 JP-A-61-158313 JP-A-3-87606 JP 2002-39724 A

  By the way, in the manufacturing process of the cylinder block for automobiles in recent years, more precise inspection is required. There is a demand for more accurate observation and measurement of not only the concave and convex shape of the cylinder inner wall, but also its surface state. For example, on the inner wall of an aluminum cylinder, a special substance having a different material from that of aluminum protrudes in order to reduce friction with the piston. Thus, the clearance between the cylinder and the piston is maintained, and an oil film that protects the cylinder inner wall is stably formed. Therefore, if the protruding amount and distribution of protruding materials of different materials can be managed, the performance and life of the engine can be improved.

When performing a more precise inspection as described above, it is necessary to use a high-resolution objective lens or detector. In this case, if three-dimensional measurement is performed, the measurement time becomes long. In particular, when inspecting a wide area or the entire surface of the cylinder inner wall, there is a problem that the inspection time is long and productivity is lowered.
The present invention has been made in view of the above problems, and an object thereof is to provide an inspection apparatus and an inspection method capable of performing a precise inspection in a short time, and a method of manufacturing a cylinder block using the inspection apparatus. And

  The inspection apparatus according to the first aspect of the present invention is provided for a hole (for example, a cylinder 22 according to an embodiment of the present invention) provided in a sample (for example, a cylinder block 21 according to an embodiment of the present invention). An inspection apparatus for inspecting the inner wall surface of the hole by inserting a lens barrel (for example, the outer cylinder 35 according to the embodiment of the present invention), and a light source (for example, the light source 11 according to the embodiment of the present invention) ), Light conversion means (for example, a cylindrical lens 42 according to an embodiment of the present invention) for converting light from the light source into line light, and an optical system for causing the line light to enter the lens barrel (For example, the confocal optical head 12 according to the embodiment of the present invention) and an objective lens that collects the line-shaped light incident on the lens barrel (for example, the objective lens 33 according to the embodiment of the present invention). And before Focus position changing means for changing the focus position of the objective lens (for example, the objective lens focusing motor 32 according to an embodiment of the present invention) and the light provided in the lens barrel and converted into the line shape A mirror (for example, a bending mirror 34 according to an embodiment of the present invention) that reflects in the direction of the wall surface, and the lens barrel are rotated so as to change the reflection direction of the mirror, and the line-shaped light is transmitted to the lens barrel. A circumferential scanning means (for example, a θ rotation motor 31 according to an embodiment of the present invention) that scans in the circumferential direction and a detector that detects reflected light reflected by the inner wall surface via a confocal optical system. A detector having detection pixels provided corresponding to the direction of the reflected light (for example, the detector 46 according to an embodiment of the present invention), and scanning the line-shaped light in the axial direction of the lens barrel. Axis Direction scanning means (for example, the mirror 44 according to the embodiment of the present invention). As a result, precise inspection can be performed in a short time.

The inspection apparatus according to the second aspect of the present invention is the inspection apparatus described above , wherein the line-shaped light is arranged such that the longitudinal direction of the line-shaped light is substantially perpendicular to the axial direction of the barrel. The inner wall surface is irradiated. Thereby, focusing can be performed easily.

  An inspection apparatus according to a third aspect of the present invention is the inspection apparatus described above, wherein the objective lens is disposed on an axis of the lens barrel, and the mirror is provided on a distal end side of the lens barrel with respect to the objective lens. It is what. Thereby, it can test | inspect with respect to a narrow hole.

  In the inspection method according to the fourth aspect of the present invention, a lens barrel is inserted into a hole provided in a sample, linear light is incident on the lens barrel, and the linear light is incident on the hole. Detection that is reflected in the direction of the inner wall surface, changes the focal position of the objective lens that focuses the linear light incident on the lens barrel on the inner wall surface, and is arranged in a line corresponding to the direction of the light A detector having pixels detects reflected light reflected by the inner wall surface via a confocal optical system, scans the line-shaped light in the axial direction of the lens barrel, and determines the focal position of the objective lens. The focal point position of the objective lens is calculated based on the detection data from the detector when changed, and the inner wall surface of the sample is inspected based on the detection data at the focal point position. As a result, precise inspection can be performed in a short time.

  An inspection method according to a fifth aspect of the present invention is the inspection method described above, wherein the inspection is performed by scanning the direction in which the line-shaped light is reflected in the circumferential direction of the lens barrel. As a result, the entire inner wall can be inspected.

Inspection method according to a sixth aspect of the present invention, in the inspection method described above, so that the longitudinal direction of the line-shaped light along the axial direction and substantially perpendicular to the direction of the lens barrel, the line-shaped light The inner wall surface is irradiated. Thereby, focusing can be performed easily.

  An inspection method according to a seventh aspect of the present invention is the above-described inspection method, wherein the hole provided in the sample is a cylinder provided in the engine cylinder block, and the protruding material protrudes from the inner wall surface of the cylinder block. The cylinder block is inspected by calculating the distribution and the volume of the cylinder based on the change of the in-focus position and the detection data. Thereby, an inspection can be performed more precisely.

  An inspection apparatus according to an eighth aspect of the present invention is the above-described inspection apparatus, wherein the inspection apparatus determines whether the substance is a protruding substance based on a result of comparing the detection data with a threshold value, and determines the distribution of the protruding substance. The volume of the protruding material is calculated based on the change in the focal position at the location determined to be the protruding material. Thereby, an inspection can be performed more precisely.

  The cylinder block manufacturing method according to the ninth aspect of the present invention is such that the cylinder block is inspected by the above-described inspection apparatus, and the quality is determined based on the inspection result. Thereby, productivity can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the inspection apparatus and inspection method which can perform a precise inspection in a short time, and the manufacturing method of a cylinder block using the same can be provided.

  Hereinafter, embodiments to which the present invention can be applied will be described. The following description is to describe the embodiment of the present invention, and the present invention is not limited to the following embodiment. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Moreover, those skilled in the art can easily change, add, and convert each element of the following embodiments within the scope of the present invention. In addition, in each drawing, the same code | symbol is attached | subjected to the same element, and duplication description is abbreviate | omitted as needed for clarification of description.

  The configuration of the inspection apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a side view showing the overall configuration of the inspection apparatus. In FIG. 1, 10 is a base, 11 is a Z guide, 12 is a confocal optical head, 13 is a stage, 14 is a pedestal block, 21 is a cylinder block, 22 is a cylinder, 31 is a θ rotation motor, and 32 is an objective lens focusing device. A motor, 33 is an objective lens, 34 is a bending mirror, 35 is an outer cylinder, 36 is an inner cylinder, and 37 is a bearing. In this embodiment, an example of inspecting a cylinder block of an automobile engine will be described. That is, in the present embodiment, description will be made assuming that the sample is a cylinder block 21 having a plurality of cylinders 22. Then, the inner wall surface of the cylinder 22 is observed and measured, and the distribution and volume of the protruding substance formed on the surface are obtained. Whether the cylinder block 21 is good or bad is determined based on the distribution and volume of the protruding material. In the present embodiment, as shown in FIG. 1, the vertical direction is the Z direction, and the axial direction of the cylinder 22 is the Y direction. Further, a direction perpendicular to the Z direction and the Y direction is taken as an X direction.

  A stage 13 is provided on the base 10. The stage 13 is, for example, an XY stage, and can move the cylinder block 21 in the horizontal direction (XY direction). A cylinder block 21 is placed on the stage 13 via a pedestal block 14 for height adjustment. The cylinder block 21 is provided with four cylinders 22 as shown in FIG. FIG. 2 is a front view showing the configuration of the cylinder block 21. Four cylinders 22 provided in the cylinder block 21 are arranged along the vertical direction. The inspection apparatus 100 according to the present embodiment performs an inspection by observing the inner wall of the cylinder 22.

  As shown in FIG. 1, in the inspection apparatus 100 according to the present embodiment, a confocal optical head 12 provided for performing an inspection is attached to a base 10 via a Z guide 11. The confocal optical head 12 moves along the Z guide 11 in the Z direction. That is, the confocal optical head is slidably provided by the Z guide 11. Therefore, the confocal optical head 12 can be moved in the vertical direction, and the height can be adjusted according to the size of the cylinder block 21 and the position of the cylinder 22.

  The confocal optical head 12 is provided with an optical system including a light source and a detector. The configuration of the optical system included in the confocal optical head 12 will be described later. An inner cylinder 36 and an outer cylinder 35 are provided so as to protrude in the Y direction from the stage 13 side of the confocal optical head 12. The inner cylinder 36 and the outer cylinder 35 are barrels and are formed in a hollow cylindrical shape. Therefore, the inside of the inner cylinder 36 and the outer cylinder 35 is an optical path for illumination light and detection light. That is, the illumination light emitted from the illumination light source provided in the confocal optical head 12 passes through the inner cylinder 36 and the outer cylinder 35 and is applied to the inner wall of the cylinder 22. Then, the reflected light reflected by the inner wall of the cylinder 22 passes through the inner cylinder 36 and the outer cylinder 35 and is detected by a detector provided in the confocal optical head 12. A cylindrical objective lens 33 is attached to the distal end side of the inner cylinder 36 extending from the confocal optical head 12. A bending mirror 34 is attached to the distal end side of the outer cylinder 35 extending from the confocal optical head 12.

  The outer cylinder 35 is attached to the housing of the confocal optical head 12 via a bearing 37. Accordingly, the outer cylinder 35 is rotatably attached to the confocal optical head 12. The outer cylinder 35 rotates around the Y axis. An inner cylinder 36 is inserted into the outer cylinder 35. The inner cylinder 36 is provided smaller than the inner diameter of the outer cylinder 35. Between the inner cylinder 36 and the outer cylinder 35, a linear bearing or the like for sliding the inner cylinder 36 is provided. The inner cylinder 36 and the outer cylinder 35 are concentric axes. The inner cylinder 36 and the outer cylinder 35 are provided along the Y direction. Therefore, the inner cylinder 36 slides in the Y direction.

  A bending mirror 34 provided in the outer cylinder 35 is inserted into the cylinder 22. Specifically, the cylinder block 21 is placed on the pedestal block 14 provided on the stage 13. Then, the height of the confocal optical head 12 is adjusted by the Z guide 11 so that the outer cylinder 35 is inserted into the cylinder 22. Further, the position of the stage 13 in the X direction is adjusted so that the outer cylinder 35 is inserted into the cylinder 22. Then, the stage 13 is moved in the Y direction to bring the cylinder block 21 and the confocal optical head 12 closer to each other. Then, the stage 13 is moved until the bending mirror 34 is inserted into the cylinder 22. At this time, it is preferable to drive the stage 13 and the Z guide 11 so that the center axis of the cylinder 22 and the center axis of the outer cylinder 35 coincide.

  The light beam from the illumination light source provided in the confocal optical head 12 is introduced into the inner cylinder 36. At this time, the optical system is disposed so that the optical axis of the light beam coincides with the central axes of the inner cylinder 36 and the outer cylinder. Therefore, the light beam is propagated along the Y direction to the tip side of the inner cylinder 36 and the outer cylinder 35 and enters the objective lens 33. The light beam is refracted by the objective lens 33 and enters the bending mirror 34. The reflecting surface of the bending mirror 34 is disposed so as to be inclined by 45 ° with respect to the optical axis of the light beam. Therefore, the light beam is bent by 90 ° as shown in FIG. Here, a window portion is provided on the side surface of the outer cylinder 35 so that the light beam bent by the bending mirror 34 passes therethrough. Specifically, an opening for transmitting the light beam is provided on the side surface of the outer cylinder 35 on the vertically lower side. Note that not only the opening but also a transparent plate that transmits light may be provided. The light beam bent by the bending mirror 34 is applied to the inner wall of the cylinder 22. The light beam reflected by the inner wall of the cylinder 22 propagates along the same path as that of the incident light and is detected by a detector provided in the confocal optical head 12.

  The confocal optical head 12 is provided with a θ rotation motor 31. The θ rotation motor 31 rotates the outer cylinder 35 in the θ direction (circumferential direction) about the Y axis as a rotation axis. Thereby, the bending mirror 34 rotates, and the incident position of the light beam on the inner wall of the cylinder 22 changes. That is, the direction of reflection by the bending mirror 34 and the position of the window portion rotate about the optical axis of the objective lens 33 as the central axis. Thereby, the light beam can be scanned along the θ direction (circumferential direction) of the cylinder 22. That is, the light beam can be bent in a direction other than the vertically downward direction shown in FIG. When the θ rotation motor 31 is driven and rotated 360 °, the entire inner wall of the cylinder 22 can be observed. Further, by vibrating a vibrating mirror or the like provided in the confocal optical head 12, the incident position of the light beam on the inner wall of the cylinder moves in the Y direction. Thereby, the light beam can be scanned in the axial direction of the cylinder 22. Furthermore, the incident position of the light beam with respect to the cylinder 22 can be shifted by moving the stage 13 in the Y direction. Therefore, the illumination light beam can be incident on the entire inner wall of the cylinder 22, and the entire inner wall of the cylinder 22 can be observed and measured.

  Further, the confocal optical head 12 is provided with an objective lens focusing motor 32. By driving the objective lens focusing motor 32, the inner cylinder 36 slides in the Y direction. Thereby, the position of the objective lens 33 attached to the inner cylinder 36 in the Y direction changes. Therefore, the focal position of the objective lens 33 can be changed. That is, the in-focus position of the objective lens 33 can be scanned along the optical axis direction. Specifically, since the focal position of the objective lens changes in the Z direction, the focal position can be scanned in the radial direction (r direction) of the cylinder 22. Thereby, focusing can be easily performed, and observation at an in-focus position can be performed at an arbitrary position on the inner wall of the cylinder 22. At this time, since the position of the outer cylinder 35 provided with the bending mirror 34 does not change, the light beam enters the same position on the inner wall of the cylinder 22. That is, even if the position of the inner cylinder 36 to which the objective lens 33 is fixed is changed, the position of the outer cylinder 35 fixed to the housing of the confocal optical head 12 does not change.

Next, the configuration of the optical system of the inspection apparatus according to the present embodiment will be described with reference to FIG. FIG. 3A is a diagram illustrating a configuration of an optical system of the inspection apparatus according to the present embodiment. FIG. 3B is an enlarged side sectional view showing a lens barrel portion of the optical system of the inspection apparatus. Note that the description of the same configuration as in FIGS. 1 and 2 is omitted. In the housing of the confocal optical head 12, there are a light source 41, a cylindrical lens 42, a polarization beam splitter (hereinafter referred to as PBS) 43, a λ / 4 plate 51, a mirror 44, a detector 46, a lens 47, a lens 48, and a relay lens 49. Is provided. The light source 41 is, for example, a laser light source, and emits a light beam for illuminating the cylinder inner wall. The light beam from the light source 41 is converted into linear light by the cylindrical lens 42. That is, the cylindrical lens 42 refracts the light beam in a direction corresponding to the X direction. The light converting means for converting the light beam from the light source 41 into line light is not limited to the cylindrical lens 42 but may be a slit or the like. The light source 41 is not limited to a laser light source, and may be a lamp light source.
The confocal microscope used in the inspection apparatus according to the present invention is, for example, as shown in Japanese Patent Application Laid-Open No. 10-104523 filed by the applicant of the present application, in the longitudinal direction of the line illumination using a scanning mirror or the like. The sample is scanned in a direction orthogonal to the sample, and this is synchronously detected by a one-dimensional image sensor, thereby obtaining a two-dimensional confocal image (slice image) for one field of view. Furthermore, while moving the focal point in the optical axis direction, each focal point position and slice image are recorded in the focal point movement memory, and by processing these images, a three-dimensional structure, a cross-sectional shape, a volume, and the like can be calculated and displayed. . In other words, the height of the surface is obtained from the focal position corresponding to the pixel indicating the peak of the slice image.

  As shown in FIG. 3A, the linear light beam emitted from the cylindrical lens 42 is refracted by the lens 47 and enters the PBS 43. The PBS 43 reflects a part of the incident light beam in the direction of the mirror 44. For example, the PBS 43 transmits the P-polarized component and reflects the S-polarized component. Here, the polarization axis is adjusted so that the light from the light source 41 is efficiently reflected. A λ / 4 plate 51 is disposed between the PBS 43 and the mirror 44. The λ / 4 plate 51 circularly polarizes the S polarization component reflected by the PBS 43. The light transmitted through the λ / 4 plate enters the mirror 44. The mirror 44 reflects the light beam from the PBS 43 toward the objective lens 33. The mirror 44 is a scanning mirror such as a galvanometer mirror. By vibrating the mirror 44, the light beam is scanned. Here, the mirror 44 is disposed on an extension line of the central axis of the inner cylinder 36 and the outer cylinder 35. Thereby, the line-shaped light beam is incident on the inner cylinder 36 and the outer cylinder 35. The light beam reflected by the mirror 44 enters the inner cylinder 36 and the outer cylinder 35 through the relay lens 49. Then, the light beam propagates along the central axis of the inner cylinder 36 and the outer cylinder 35 and enters the objective lens 33. Here, as shown in FIG. 3B, the central axis of the cylinder 22, that is, the central axis of the inner cylinder 36 and the outer cylinder 35 is the θy axis. Then, the light beam from the confocal optical head 12 propagates along the θy axis. The θy axis that is the central axis of the cylinder 22 and the Y axis of the stage 13 coincide with each other. As shown in FIG. 3A, the objective lens 33 refracts the incident light beam and focuses it on the inner wall of the cylinder 22. Further, a bending mirror 34 is provided on the exit side of the objective lens 33, and the light beam from the objective lens is bent by 90 ° to irradiate the inner wall of the cylinder 22. At this time, as shown in FIG. 3B, the light beam reflected by the bending mirror 34 passes through an opening 35 a provided in the outer cylinder 35. Thus, the light converted into a line by the cylindrical lens 42 is imaged on the inner wall of the cylinder 22.

  By disposing the objective lens 33 in the optical path between the bending mirror 34 and the light source 41, the outer diameter of the outer cylinder 35 can be reduced. That is, in the case of the configuration in which the light beam bent by the bending mirror 34 is incident on the objective lens 33, the diameter is increased by the length of the objective lens 33. Therefore, it cannot be inserted into the thin cylinder 22. Therefore, it is preferable that the bending mirror 34 is provided on the tip side of the objective lens 33. Thereby, it can test | inspect also with respect to the cylinder 22 with a small internal diameter. In this case, for example, the cylinder 22 having an inner diameter of about 30 mm can be inspected by using a long working objective lens and attaching a bending mirror to the tip.

  The light beam bent by the bending mirror 34 is incident substantially perpendicular to the inner wall of the cylinder 22. Therefore, the reflected light reflected by the surface of the inner wall of the cylinder 22 propagates through the same optical path as the incident light incident on the inner wall of the cylinder 22 from the objective lens 33. That is, the reflected light reflected by the inner wall of the cylinder 22 is reflected by the bending mirror 34 and enters the objective lens 33. The reflected light incident on the objective lens 33 is refracted by the objective lens 33, refracted by the relay lens 49, and enters the mirror 44. The mirror 44 reflects the reflected light from the objective lens 33 to the λ / 4 plate 51. Part of the reflected light that has entered the PBS 43 passes through the PBS 43, is refracted by the lens 48, and enters the detector 46. Here, since the reflected light passes through the λ / 4 plate, the circularly polarized light becomes linearly polarized light. Then, since the light beam from the light source 41 passes twice through the λ / 4 plate 51, P-polarized light is polarized to S-polarized light. Therefore, the reflected light passes through the PBS 43 and efficiently enters the detector 46.

  The detector 46 is a one-dimensional line CCD camera, for example, and outputs a detection signal corresponding to the intensity of incident light. The plurality of pixels provided in the detector 46 are provided in a direction corresponding to the X direction in the cylinder 22. That is, the detection pixels of the detector 46 are arranged along the direction of the line-shaped reflected light emitted from the bending mirror 34 and the objective lens 33. The light receiving surface of the detector 46 and the surface of the inner wall of the cylinder 22 are arranged in a conjugate imaging relationship. That is, the optical system and the objective lens 33 included in the confocal optical head 12 constitute a slit confocal optical system. As a result, the light beam converted into a line by the cylindrical lens 42 is condensed on the surface of the inner wall of the cylinder 22 by the objective lens 33. Further, the reflected light reflected by the surface of the inner wall of the cylinder 22 forms an image on the light receiving surface of the detector 46. The detector 46 detects incident light through the confocal optical system. Accordingly, the reflected light from the position defocused is blurred at the position of the light receiving surface of the detector 46 and passes outside the light receiving surface, so that the light intensity is weakened. As a result, the image out of focus disappears, and the inner wall surface can be accurately inspected. Reflected light from other than the focal position of the objective lens 33 does not enter the detection pixels of the detector 46. The detector 46 outputs the detected data to a processing device (not shown).

  In the confocal optical system, when the in-focus position of the objective lens 33 is arranged on the sample surface, the detected light amount becomes the largest. Therefore, when the light is condensed on the surface of the inner wall of the cylinder 22, the detected light amount becomes the largest. In the present invention, a linear bearing 38 is provided between the inner cylinder 36 and the outer cylinder 35 as shown in FIG. As a result, the inner cylinder 36 slides relative to the outer cylinder 35. Therefore, the focus position can be changed by driving the objective lens focusing motor 32 and moving the position of the inner cylinder 36. Then, the position where the amount of light detected by the detector 46 is maximum is determined as the in-focus position. That is, the distance between the inner wall of the cylinder 22 and the objective lens 33 at the in-focus position is calculated from the position of the inner cylinder 36 when the detected light quantity is maximum. And the surface shape of the cylinder 22 can be calculated | required by calculating the change of an in-focus position when scanning an illumination area | region. Furthermore, it is also possible to obtain the irregular shape and inner diameter of the inner wall of the cylinder 22. Specifically, the focal point position is close to the objective lens at a portion that is convex on the inner wall surface of the cylinder 22. Thereby, the distribution of the protruding substance formed on the surface of the inner wall of the cylinder 22 can be obtained. Further, the focal position is determined for each pixel of the detector 46.

  Next, the inspection procedure of the cylinder block 21 will be described with reference to FIG. FIG. 4 is a flowchart showing a procedure for inspecting the cylinder block 21 in a strip shape. First, the cylinder block 21 to be inspected is set on the stage 13 of the inspection apparatus (step S101). Specifically, the cylinder block 21 to be observed is placed on the stage 13. Next, the XYZ axes are moved to insert the bending mirror 34 into the cylinder 22 (step S102). A Z guide 11 is used for driving the Z axis, and a stage 13 is used for driving the X axis and the Y axis. A bending mirror 34 is disposed at the end of the cylinder 22 on the confocal optical head 12 side. Thereby, the end of the cylinder 22 can be irradiated with a light beam for illumination.

  Next, the objective lens 33 is scanned in the focal direction to acquire data (step S103). Specifically, the objective lens focusing motor 32 is driven to change the position of the inner cylinder 36 to which the objective lens 33 is attached in the Y direction. Thereby, the focal position of the objective lens 33 is scanned along the optical axis direction. Then, detection is performed by the detector 46 while scanning the objective lens 33. Detection data from the detector 46 is stored in the processing device.

  Here, on the surface of the inner wall of the cylinder 22, it is preferable that the longitudinal direction of the linear light beam is a direction perpendicular to the θy direction. That is, it is preferable to collect the line-shaped light beam along a direction perpendicular to the Y direction. In other words, as shown in FIG. 5, it is preferable that the irradiation region 50 of the linear light beam on the inner wall of the cylinder 22 is arranged in a direction perpendicular to the axial direction (Y direction) of the cylinder 22. FIG. 5 is a perspective view schematically showing a light beam irradiation region 50 on the surface of the cylinder 22. The irradiation area 50 shown in FIG. 5 corresponds to each visual field. Thus, by arranging the irradiation region 50, focusing can be easily performed. For example, considering the case where the bending mirror 34 reflects the light beam vertically downward, when the irradiation region 50 is irradiated along the X direction, the irradiation region 50 is disposed on the curved surface in the cylinder 22. Since the cylinder 22 is cylindrical, the height in the Z direction changes when the position in the X direction changes. When the light beam is condensed on the surface of the inner wall of the cylinder 22, a part of the irradiation region 50 becomes a focal point position. In this case, one of the pixels of the detector 46 becomes the focal position, and the detected light amount increases. That is, it is possible to prevent the detected light amount from being weakened in all the pixels of the detector 46, and focusing can be easily performed.

  For example, when the vicinity of the center of the line-shaped irradiation region 50 is the in-focus position, the detected light amount is increased in the pixels near the center of the detector 46. At this time, in the vicinity of both ends of the line-shaped illumination area, the focal point position is not reached, so that the detected light amount becomes weaker as the pixels of the detector 46 approach both ends. When the objective lens 33 is moved away from the surface of the inner wall of the cylinder 22, the vicinity of the center of the irradiation region 50 is separated from the focal point position, and the vicinity of both ends of the irradiation region 50 is the focal point position. As described above, since any one of the pixels is in the focal point position, the objective lens 33 can be easily scanned. Furthermore, since the scanning direction of the objective lens 33 can be determined based on the change in the pixel serving as the in-focus position, scanning can be performed efficiently.

  Data can be acquired by scanning the objective lens 33 as described above. Here, in the irradiation region 50, the change in the detected light amount due to the radial position of the cylinder 22 can be obtained. That is, the objective lens 33 is changed along the optical axis direction, and the reflected light is detected while scanning the focal position in the radial direction (r direction) of the cylinder. Thereby, in each pixel of the detector 46, the focal position of the objective lens 33 and the detected light quantity are associated with each other and stored in the processing device. That is, the focal position of the objective lens 33 is calculated based on position information of the objective lens focusing motor 32. The configuration of the processing apparatus will be described later. Here, the position of the objective lens 33 when the detected light amount is maximum in each pixel corresponds to the focal point position in that pixel. Based on the detection data from the detector 46, the processing device determines the position of the objective lens when the detected light amount is maximum as the in-focus position. Further, the processing device calculates a focal position for each pixel.

  Next, the Y axis is moved by one field of view to acquire data (step S104). Specifically, first, the inclination of the mirror 44 is changed to change the reflection direction of the light beam. Then, the light beam is moved by one field of view, and the irradiation area 50 is shifted in the Y direction. Thereby, the irradiation area 50 shown in FIG. 5 moves in the Y direction. That is, the incident position of the light beam on the θy axis is shifted by one field of view. Then, similarly to step S103, the objective lens 33 is scanned to acquire data.

  Then, the above process is repeated to acquire all the data in the longitudinal direction of the cylinder 22 (step S105). That is, the irradiation area 50 is shifted by one field of view, and scanning is performed in the axial direction (Y direction). That is, the mirror 44 is driven to shift the incident position of the light beam. Further, the stage 13 is driven to move the position of the cylinder 22. Then, the irradiation region 50 is moved until the end on the opposite side of the cylinder 22 is illuminated. Thereby, the three-dimensional data of the inner wall of the cylinder 22 can be acquired. Here, since scanning is not performed in the circumferential direction of the cylinder 22, data of the band-shaped region can be acquired. That is, since the θ rotation motor is not operated, as shown in FIG. 5, the band-like region of the cylinder 22 along the Y direction is illuminated.

  Then, the screen is connected based on the above data by the analysis software of the processing device (step S106). Specifically, image processing is performed by the processing device, and the data of each pixel is connected based on the detected data and its coordinates. As a result, the detection data is connected in a band shape according to the illumination position. Then, the three-dimensional data connected in a strip shape is analyzed, and the distribution and volume of the protruding substance formed on the inner wall of the cylinder 22 are obtained (step S107). Then, the distribution and volume of the protruding substance are compared with the standard, and a pass / fail decision is made (step S108). In this way, the inner wall of the cylinder 22 is inspected. Further, the above process may be repeated to inspect all four cylinders 22 provided in the cylinder block 21.

  As described above, the inspection time can be shortened by illuminating with line-shaped light. Furthermore, the objective lens can be easily scanned by irradiating the line-shaped light in a direction substantially perpendicular to the axial direction. In this case, focusing can be easily performed even when the optical axis and the axis of the cylinder 22 do not coincide with each other. That is, when the optical axis and the axis of the cylinder 22 do not coincide with each other, when the irradiation area is scanned, the in-focus position may deviate from the surface of the cylinder 22. If the in-focus position completely deviates from the inner wall surface, it may take a long time to move the objective lens to the in-focus position again. However, by irradiating the line-shaped light in the direction perpendicular to the axial direction, the focal point position is obtained in any of the pixels, so that focusing can be easily performed. The scanning is not limited to the configuration in which the stage 13 is driven to perform the scanning in the Y direction, and the confocal optical head 12 may be driven to perform the scanning. That is, at least one of the cylinder block and the optical system may be moved so as to change the relative position between the bending mirror 34 and the cylinder 22 in the axial direction of the cylinder 22. Further, the scanning of the focal position is not limited to the configuration in which the objective lens 33 is moved. For example, the focal position may be scanned by moving a lens other than the objective lens.

  In the above inspection, the band-shaped region is inspected, but the entire inner wall of the cylinder 22 may be inspected. In this case, the inspection procedure is as shown in FIG. FIG. 6 is a flowchart showing an inspection procedure when the entire inner wall of the cylinder 22 is inspected. Note that description of the same steps as those in FIG. 4 is omitted.

  First, the cylinder block 21 is set on the stage 13 of the inspection apparatus (step S202). Next, the XYZ axes are moved to insert the bending mirror 34 into the cylinder 22 (step S202). Then, the objective lens 33 is scanned in the focal direction to acquire data (step S203). When the data acquisition is completed, the data is acquired by moving one field of view on the Y axis (step S204). And step S204 is repeated and all the data of a longitudinal direction are acquired (step S205). Thereby, the strip | belt-shaped area | region of the cylinder 22 is observed. The steps from step S201 to step S205 are the same as the steps from step S101 to step S105 shown in FIG. In this way, data of the band-like region of the inner wall of the cylinder 22 is acquired.

  Next, the stage 13 is moved in the Y direction to return the position of the cylinder 22 with respect to the bending mirror 34 (step S206). As a result, the position of the bending mirror 34 returns to the end of the cylinder 22. Then, the θ rotation motor 31 rotates the bending mirror by one field of view in the circumferential direction to acquire data (step S207). Further, the focal position is scanned in the same manner as in step S103 to acquire data. Then, similarly to step S204, the Y axis is moved by one field of view to acquire data (step S208). And step S208 is repeated and the data of a longitudinal direction are acquired (step S209). As a result, data is acquired for the band-like region for two fields of view of the cylinder 22.

  Further, step S206 to step S209 are repeated for one round, and data for the entire inner wall of the cylinder 22 is acquired (step S210). As a result, three-dimensional data for the entire inner wall of the cylinder 22 is acquired, and the entire inner wall of the cylinder 22 can be observed with a confocal microscope. Then, the above data is connected to the screen by analysis software (step S211). Thereby, detection data can be connected in a cylindrical shape. Then, the data connected in a cylindrical shape is analyzed to determine the distribution and volume of the protruding substance (step S212). Then, the distribution and volume of the protruding substance are compared with the standard, and a pass / fail decision is made (step S213). As a result, the entire inner wall of the cylinder 22 can be observed and measured. Therefore, the inspection can be performed more accurately. The inspection is not limited to the entire inner wall of the cylinder 22 but may be performed on a partial region of the inner wall of the cylinder 22. That is, it is only necessary to perform scanning so as to irradiate the light beam to the region to be inspected for the cylinder 22. Further, when the optical axis and the axis of the cylinder 22 do not coincide with each other, if the scanning is performed in the θ direction, the focal position is shifted from the inner wall surface. However, it is possible to prevent the focal position from completely deviating from the inner wall surface by irradiating light in a direction perpendicular to the axial direction. Therefore, even when the optical axis and the axis of the cylinder 22 do not coincide with each other, scanning can be easily performed. This eliminates the need for the optical axis and the axis of the cylinder 22 to coincide with each other, so that the inspection can be easily performed.

  Next, the configuration of the processing apparatus that performs the above-described inspection processing will be described with reference to FIGS. FIG. 7 is a block diagram showing the configuration of the inspection apparatus. FIG. 8 is a diagram schematically showing the inner wall surface of the cylinder. The processing device 70 is, for example, an information processing device such as a personal computer, and includes a data storage unit 71, a focal position calculation unit 72, a distribution calculation unit 73, a volume calculation unit 74, a pass / fail determination unit 75, and a control unit 76. ing. The processing device 70 is connected to the stage 13, the θ rotation motor 31, the objective lens focusing motor 32, and the detector 46.

  The data storage unit 71 stores detection data from the detector 46. The control unit 76 performs drive control of the stage 13, the θ rotation motor 31, and the objective lens focusing motor 32. The position information of the stage 13, the θ rotation motor 31, and the objective lens focusing motor 32 is stored in the data storage unit 71 in association with the detection data. That is, the data storage unit 71 stores the coordinates of the focal position with respect to the inner wall surface of the cylinder 22 and the detected light amount in association with each other. Specifically, the angle of the mirror 44, the position of the stage 13 in the Y direction, the rotation angle of the bending mirror 34, the position of the objective lens 33 in the Y direction, and the like are stored in association with the detection data from the detector 46.

  The in-focus position calculation unit 72 calculates the in-focus position based on the data stored in the data storage unit 71. That is, in each pixel, the focal position is calculated based on the position of the objective lens 33 (position information of the objective lens focusing motor 32) when the detected light amount is the largest. When the detection data at the in-focus position detected for each coordinate are connected, the result is as shown in FIG. Here, 60 is a cylinder inner wall, and 61 is a protruding substance protruding from the cylinder inner wall. The projecting material 61 usually has a lower reflectance than the cylinder inner wall 60 made of Al. Accordingly, the amount of light detected by the detector 46 is reduced at the location where the protruding substance 61 is formed. Thus, on the inner wall surface of the cylinder 22, a difference in reflectance occurs due to the difference in material.

  The distribution calculation unit 73 calculates the distribution of protruding substances. Specifically, the detection data at the in-focus position is compared with a threshold value, and it is determined that the protruding substance 61 is formed at the location of the cylinder inner wall 60 where the detected light amount is a certain value or less. That is, it is determined that a portion where the detected light amount is equal to or less than the threshold value is a protruding substance, and a portion where the detected light amount is equal to or greater than the threshold value is not the protruding substance 61. Thereby, the distribution of the protruding substance 61 on the inner wall of the cylinder 22 can be calculated. The determination result is as shown in FIG. Thus, by detecting through the confocal optical system, it is possible to calculate the distribution of the protruding substance based on the difference in the detected light amount caused by the difference in the reflectance of the inner wall surface.

  Then, the volume calculation unit 74 calculates the volume of the protruding substance 61 formed on the cylinder inner wall 60. Specifically, the volume is calculated based on the change in the focal position at the location where the projecting substance 61 is determined to be formed by the distribution calculation unit 73. That is, the height of the surface of the projecting substance 61 is obtained from the surface of the cylinder inner wall 60 based on the difference in the focal point position between the cylinder inner wall 60 and the surface of the projecting substance 61. And the volume of the protrusion substance 61 can be calculated | required by adding the focal movement amount of the pixel which shows the peak of each slice image. Furthermore, the three-dimensional shape of the protruding substance 61 as shown in FIG. 8C can be obtained. In addition, the height of the protruding substance 61 can be measured, and the inspection may be performed based on the height of the protruding substance 61.

  The pass / fail determination unit 75 determines pass / fail of the cylinder block 21 based on the distribution of the protruding material 61 calculated by the distribution calculating unit 73 and the volume of the protruding material 61 calculated by the volume calculating unit 74. Specifically, it is determined whether the ratio of the protruding substance 61 to the surface area of the cylinder inner wall is included in a certain range and whether the total volume of the protruding substance is included in the certain range. That is, the calculated volume of the protruding substance 61 is compared with the standard, and the pass / fail judgment of the cylinder 22 is performed. The cylinder block 21 including the cylinder 22 determined to be unacceptable is regarded as a defective product, and the cylinder block 21 including only the cylinder 22 determined as acceptable is determined to be a non-defective product.

  Thus, a more precise inspection can be performed by performing an inspection based on the volume and distribution of the protruding substance 61. Therefore, the quality determination of the engine cylinder block can be performed more strictly. By performing the inspection using this inspection apparatus, the performance and life of the engine can be improved. That is, a long-life, high-performance engine can be produced stably. Furthermore, since inspection can be performed in a short time, productivity can be improved. The inspection described above can be used not only for slit confocals but also for pinhole confocal optical systems. That is, the beam spot is two-dimensionally scanned with respect to the sample surface to form a two-dimensional image, and the height of the protruding substance is obtained by changing the focal position. Then, the volume and distribution of the protruding substance may be obtained and the inspection may be performed.

Embodiment 2 of the Invention
The inspection apparatus according to this embodiment will be described with reference to FIG. FIG. 9 is a side view showing the configuration of the inspection apparatus according to the present embodiment. Since the basic configuration of the inspection apparatus according to the present embodiment is the same as that of the first embodiment, the description thereof is omitted. Therefore, in this embodiment, a configuration different from that in Embodiment 1 will be described. In the present embodiment, the illumination light from the light source is bent by the bending mirror 34 and then condensed by the objective lens 33. Specifically, a bending mirror housing 39 is attached to the distal end side of the outer cylinder 35. A bending mirror 34 is included in the bending mirror housing 39. Similar to the embodiment, the bending mirror 34 is disposed inclined with respect to the optical axis so as to bend the light beam by 90 °. Therefore, as shown in FIG. 3, the light beam emitted from the confocal optical head 12 is reflected vertically downward.

  An objective lens 33 is provided on the side surface of the bending mirror housing 38. The objective lens 33 is provided on the side surface of the bending mirror housing 38 on the vertically lower side. Accordingly, the illumination light bent by the bending mirror 34 enters the objective lens 33. The objective lens 33 condenses the incident light beam on the surface of the inner wall of the cylinder 22. In the housing of the confocal optical head 12, a θ rotation motor (not shown) and an objective lens focusing motor (not shown) are provided as in the first embodiment. In the present embodiment, the objective lens 33 is focused by moving the relay lens or the like in the optical system in the optical axis direction by the objective lens focusing motor.

  The outer cylinder 35 is attached to the housing of the confocal optical head 12 via a θ rotation mechanism 38. When the θ rotation motor is rotated, the outer cylinder 35 rotates in the θ direction (circumferential direction). Thereby, the bending mirror 34 and the objective lens 33 rotate, and the illumination area can be scanned in the circumferential direction. Then, the inner wall is inspected as in the first embodiment. As a result, the inspection can be performed more precisely, and the same effect as in the first embodiment can be obtained.

  In this configuration, the inner wall of the cylinder 22 having a small inner diameter cannot be inspected as compared with the first embodiment, but an objective lens having a short working distance can be used. That is, as shown in FIG. 10, the bending mirror housing 39 and the objective lens 33 attached to the side surface thereof are inserted into the cylinder 22. Therefore, the portion inserted into the cylinder 22 becomes larger than the diameter of the outer cylinder 35. However, since the distance between the objective lens 33 and the cylinder surface can be reduced, the objective lens 33 having a short working distance can be used. Therefore, the inspection apparatus according to this embodiment is suitable for inspection of a cylinder having a large inner diameter.

  By performing the inspection shown in the first and second embodiments on a cylinder block created by casting a metal material such as aluminum, the productivity of the cylinder block can be improved. Note that the inspection apparatus according to the present invention is not limited to the configuration in which the distribution and volume of the protruding material formed in the cylinder block 21 are obtained and the inspection is performed. For example, the inspection may be performed based on the distribution or volume of the protruding substance, and further, the inspection may be performed by observing the surface in the cylinder. Further, the amount of protrusion (height) of the protruding substance may be obtained from the change of the focal position, and the inspection may be performed based on the amount of protrusion (height) of the protruding substance.

  The inspection apparatus according to the present invention can inspect various samples without being limited to the cylinder block for the engine. For example, it can be widely used for the inspection and inspection of pipe inner walls and narrow portions, such as inspection of inner walls of cooling pipes for nuclear power generation, diagnosis of remaining life of welds, and the like. For example, the reflectance on the surface changes when the inner wall surface changes color, foreign matter adheres, or the material is different. Therefore, a more precise inspection can be performed by inspecting based on the change in the detected light amount at the in-focus position. In the present invention, the inner wall surface of the hole provided in the sample can be inspected by inserting a part of the lens barrel into the hole provided in the sample.

It is a side view which shows the whole structure of the test | inspection apparatus concerning this invention. It is a front view which shows the structure of the cylinder block test | inspected with the test | inspection apparatus concerning this invention. It is a figure which shows the structure of the inspection apparatus optical system concerning Embodiment 1 of this invention. It is a flowchart which shows the inspection method concerning this invention. In an inspection device concerning the present invention, it is a figure showing a cylinder and an illumination field. It is a flowchart which shows another inspection method concerning this invention. It is a figure which shows the structure of the processing apparatus used for the test | inspection apparatus concerning this invention. It is a figure which shows the inner wall surface of the cylinder test | inspected with the test | inspection apparatus concerning this invention. It is a side view which shows the whole structure of the test | inspection apparatus concerning Embodiment 2 of this invention. It is a front view which shows the structure of the cylinder block test | inspected with the test | inspection apparatus concerning this invention.

Explanation of symbols

10 base, 11 Z guide, 12 confocal optical system, 13 stage,
14 base block, 21 cylinder block, 22 cylinder,
31 θ rotation motor, 32 objective lens focusing motor, 33 objective lens 34 bending mirror, 35 outer cylinder, 36 inner cylinder, 37 bearing, 38, linear bearing,
41 light source, 42 cylindrical lens, 43 PBS, 44 mirror,
46 detector, 47 lens, 48 lens, 49 relay lens, 50 illumination area 60 cylinder inner wall, 61 projecting substance, 70 processing device, 71 data storage unit,
72 in-focus position calculation unit, 73 distribution calculation unit, 74 volume calculation unit, 75 pass / fail determination unit,
76 Control unit, 100 Inspection device

Claims (9)

An inspection apparatus for inspecting the inner wall surface of the hole by inserting a lens barrel into the hole provided in the sample,
A light source;
Light converting means for converting light from the light source into line-shaped light;
An optical system for causing the line-shaped light to enter the barrel;
An objective lens for condensing line-shaped light incident on the lens barrel;
A focal position changing means for changing a focal position of the objective lens;
A mirror that is provided in the lens barrel and reflects the light converted into the line shape toward the inner wall surface;
Rotating the lens barrel so as to change the reflection direction of the mirror, and circumferential scanning means for scanning the line-shaped light in the circumferential direction of the lens barrel;
A detector for detecting reflected light reflected by the inner wall surface via a confocal optical system, the detector having a detection pixel provided corresponding to the direction of the reflected light;
An inspection apparatus comprising: an axial scanning unit that scans the line-shaped light in the axial direction of the barrel. The inspection apparatus according to claim 1, wherein the inner wall surface is irradiated with the line-shaped light so that a longitudinal direction of the line-shaped light is along a direction substantially perpendicular to an axial direction of the lens barrel. The objective lens is disposed on an axis of the barrel;
The inspection apparatus according to claim 1, wherein the mirror is provided closer to the distal end side of the barrel than the objective lens. Insert the lens barrel into the hole provided in the sample,
Line-shaped light is incident on the lens barrel,
Reflecting the line-shaped light toward the inner wall surface of the hole;
Changing the focal position of the objective lens for condensing the line-shaped light incident on the barrel onto the inner wall surface;
By means of a detector having detection pixels arranged corresponding to the direction of the line-shaped light, the reflected light reflected by the inner wall surface is detected via a confocal optical system,
Scan the light on the line in the axial direction of the barrel,
Calculate the in-focus position of the objective lens based on the detection data from the detector when the focal position of the objective lens is changed,
An inspection method for inspecting an inner wall surface of the sample based on the detection data at the in-focus position.   The inspection method according to claim 4, wherein the inspection is performed by scanning a direction in which the linear light is reflected in a circumferential direction of the lens barrel. 6. The line-shaped light is applied to the inner wall surface so that the longitudinal direction of the line-shaped light is along a direction substantially perpendicular to the axial direction of the lens barrel. Inspection method. The hole provided in the sample is a cylinder provided in an engine cylinder block,
The inspection according to claim 4, 5 or 6, wherein the cylinder block is inspected by calculating the distribution and volume of the protruding material protruding from the inner wall surface of the cylinder block based on the change of the in-focus position and the detection data. Method. Based on the result of comparing the detection data with a threshold value, it is determined whether or not it is a protruding substance, and the distribution of the protruding substance is calculated
The inspection method according to claim 7, wherein the volume of the protruding material is calculated based on a change in the in-focus position at a location determined to be the protruding material. Cylinder block is inspected by the inspection method according to claim 7 or 8,
A method of manufacturing a cylinder block, which determines pass / fail according to the result of the inspection.

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