JP2005291771A - Surface inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect continuously the end face and the inner circumferential surface of a cylindrical body by one surface inspection apparatus. <P>SOLUTION: A circular cone body 35 forming a mirror surface 35b on the inner circumferential surface is installed oppositely over the cylindrical body 2. Inspection light from a sensor head 20 is reflected to the mirror surface 35b side of the circular cone body 35 by the mirror surface 12a of a mirror 12 disposed on the optical axis. Since both mirror surfaces 12a, 35b are disposed in parallel, the inspection light reflected by the mirror surface 35b of the circular cone body 35 is irradiated orthogonally toward the flat surface 2b of the cylindrical body 2, and scans around the flat surface 2b by rotation of the mirror 12. The distance dm between the sensor head 20 and the mirror surface 12a at that time is set based on a value determined by subtracting the distance dw between the the mirror surface 12a of the mirror 12 and the mirror surface 35b of the circular cone body 35 and the distance dh between the mirror surface 35b and the flat surface 2b from the focal distance d of the sensor head 20, to thereby enable to always fix the distance from sensor head 20 to the flat surface 2b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface inspection apparatus that scans a flat surface formed on an end surface of a cylindrical body using an optical scanning unit and inspects whether or not a defective portion exists on the flat surface.

  Generally, a piston slides on the inner peripheral surface of an engine cylinder, which is an automotive part, and a flat surface continuous with the inner peripheral surface is in close contact with the cylinder head via a gasket. If a defective portion such as a nest or a flaw is present on the inner peripheral surface or flat surface of the engine cylinder, oil leakage or cooling water leakage is likely to occur, and the reliability of the product is impaired.

  Conventionally, in a cylindrical body typified by such an engine cylinder, when inspecting the processed inner peripheral surface and the surface of a flat surface, the inspector irradiates light to the inspected portion such as the inner peripheral surface or the flat surface. In addition, the presence or absence of defects such as nests and scratches is inspected by visually observing the reflected light. Further, a part such as an inner peripheral surface that is difficult for an inspector to visually recognize directly is inspected using a fiberscope or the like.

  However, in the artificial inspection, the inspection accuracy tends to vary due to individual differences among the inspectors. Further, even in the inspection of the same person, the inspection accuracy tends to vary depending on the physical condition at that time. On the other hand, in an inspection using a fiberscope or the like, halation may occur depending on the illumination light irradiation condition, and it may be difficult to accurately recognize a defective portion. In addition, there has been proposed an apparatus for imaging the inner peripheral surface and the flat surface of a cylindrical body using a CCD camera, and inspecting the surface based on the captured image. In this case, halation may occur depending on the illumination light irradiation condition. May occur and it may be difficult to obtain an image necessary for surface inspection.

  For this reason, the present applicant has disclosed a surface inspection apparatus that recognizes a defect portion formed on the inner peripheral surface of a cylindrical body from an intensity of reflected light instead of recognizing it by an image, as disclosed in Japanese Patent Laid-Open No. 11-281583. No.).

That is, in the surface inspection apparatus disclosed in the same document, a rotating cylinder is provided at the tip of an electric motor, a light projecting fiber and a light receiving fiber are disposed in the rotating cylinder, and the rotating cylinder is placed on the axis of the cylindrical body. The rotating cylinder is rotated by rotation of the electric motor, and the inspection light from the light projecting fiber is emitted in a substantially right angle direction while moving in the direction along the rotation axis at predetermined pitches. The peripheral surface is irradiated, the reflected light is received by a light receiving fiber, and the presence or absence of a defect such as a flaw or a foreign substance is determined from the intensity of the received light.
Japanese Patent Laid-Open No. 11-281585 JP-A-8-334471

  However, since the focal length of the lens is constant, the technique disclosed in Patent Document 1 cannot cope with the case where the inner diameters of the cylindrical bodies are different. In this case, it is necessary to set one by one by exchanging lenses so that the focal length matches the inner diameter of the cylindrical body, and there is a problem that the setup becomes complicated.

  To deal with this problem, it is conceivable to variably set the focal length of the lens in accordance with the change in the inner diameter of the cylindrical body using an electric zoom or the like, but the zoom mechanism is complicated and the product cost is only increased. However, there is a problem that the outer diameter of the tip portion is increased.

  Furthermore, with the technique disclosed in Patent Document 1, the inner peripheral surface of the cylindrical body can be inspected, but the flat surface of the cylindrical body cannot be inspected.

  As a surface inspection device for detecting a defective portion on a flat surface, the present applicant has provided a plurality of fiber bundles arranged in an array at the tip in Patent Document 2 (Japanese Patent Laid-Open No. 8-334471), and each fiber A technique for detecting defects by irradiating a flat surface with inspection light emitted from a bundle of projecting fibers, receiving the reflected light with a photodiode, and comparing the amount of light received with a preset threshold value. Proposed.

  However, since the surface inspection apparatus described in Patent Document 2 is configured by arranging a plurality of fiber bundles in an array, each fiber bundle must include a light emitting diode and a photosensor. There is a problem that the number of parts increases and the product cost increases.

  In order to cope with this, it is conceivable to scan the flat surface by moving one fiber bundle vertically and horizontally along the flat surface of the cylindrical body, but there is a problem that it takes time for inspection.

  Therefore, the object of the present invention is to suppress a significant increase in product cost without increasing the size of the apparatus, and can easily cope with cylinders having different inner diameters. Not only can a significant reduction be achieved, but the surface of both the inner peripheral surface and the flat surface of the cylinder can be inspected continuously or separately with a single device, making it easy to use. To provide an apparatus.

  In order to achieve the above object, a first surface inspection apparatus according to the present invention irradiates a flat surface formed on an end surface of a cylindrical body with inspection light, and a defect exists on the flat surface based on a change in the amount of reflected light. In the surface inspection apparatus for inspecting whether or not to perform, a sensor head for emitting the inspection light in the axial direction of the cylindrical body is provided, and the inspection light intersects the optical axis on the optical axis of the sensor head A first reflecting surface that reflects in the direction and rotates relative to the cylindrical body is disposed, and a second reflecting surface that is parallel to the first reflecting surface is disposed in the reflecting direction of the first reflecting surface. And the second reflection surface is opposed to the flat surface, and the distance between the sensor head and the first reflection surface is a distance from the first reflection surface to the second reflection surface. The distance from the second reflecting surface to the flat surface is subtracted from the focal length of the sensor head. And setting, based on the value.

  In such a configuration, the inspection light from the sensor head is reflected in the direction intersecting the optical axis by the first reflecting surface, and reflected by the second reflecting surface parallel to the first reflecting surface. The flat surface formed on the end surface of the cylinder is irradiated. At this time, since the first reflecting surface rotates relative to the cylindrical body, the inspection light reflected by the first reflecting surface scans in a direction that circulates on the flat surface. Further, the distance between the sensor head and the first reflecting surface is set to the distance from the focal length of the sensor head to the second reflecting surface from the first reflecting surface to the flat surface. Since the distance is set to a value obtained by subtracting the distance to reach, the distance from the sensor head to the flat surface is always constant. Furthermore, since the objective optical system such as a lens is not moved, it is only necessary to change the distance between the sensor head and the first reflecting surface, the structure can be simplified and the outer diameter can be made relatively compact. .

  The second surface inspection apparatus is characterized in that, in the first surface inspection apparatus, the second reflecting surfaces are respectively opposed to the flat surfaces formed on both end surfaces of the cylindrical body.

  In such a configuration, the flat surfaces formed on both end surfaces of the cylinder are continuously inspected by setting the second reflecting surfaces to the flat surfaces formed on both end surfaces of the cylinder. be able to.

  According to a third surface inspection apparatus, in the first or second surface inspection apparatus, the second reflecting surface is formed on an inner surface of a cone, and an axis of the cone is an optical axis of the sensor head. It is characterized by being arranged in a matched state.

  In such a configuration, the second reflecting surface is formed on the inner surface of the cone, and the axis of the cone is arranged so as to coincide with the optical axis of the sensor head. Even if it is rotated, the distance between the first reflecting surface and the second reflecting surface is always constant, and it is easy to set the distance from the sensor head to the flat surface constant.

  The fourth surface inspection apparatus is any one of the first to third surface inspection apparatuses, wherein the first reflection surface is fixed to a rotating cylinder that is externally mounted on the sensor head. The first reflecting surface is rotated by the rotation.

  In such a configuration, the first reflecting surface is fixed to the rotating cylinder that is mounted on the sensor head, and the first reflecting surface is rotated by the rotation of the rotating cylinder. It can be easily rotated from the outside of the cylinder.

  According to a fifth surface inspection apparatus, in the fourth surface inspection apparatus, the first reflection surface is fixed to a rotary cylinder that is externally mounted on the sensor head, and the first cylinder is rotated by the rotation of the rotary cylinder. While the reflecting surface rotates, the sensor head is fixed to a cylindrical body disposed coaxially with the rotating cylinder, and moves the rotating cylinder and the cylindrical body integrally in the axial direction. The flat surface is scanned spirally.

  In such a configuration, the first reflecting surface is fixed to the rotating cylinder, the first reflecting surface is rotated by rotation of the rotating cylinder, and the sensor head is arranged on the cylindrical body coaxially with the rotating cylinder. Since the flat surface of the cylindrical body is spirally scanned by moving the rotating cylinder and the cylindrical body integrally in the axial direction, the flat surface can be continuously scanned. .

  The sixth surface inspection apparatus is the surface inspection apparatus according to any one of the first to fifth aspects, wherein the first reflection surface is inserted into the cylindrical body and moved in the axial direction while rotating relative to the cylindrical body. In this case, it also has a mechanism for inspecting whether or not there is a defect on the inner peripheral surface of the cylindrical body. In this case, the distance between the sensor head and the first reflecting surface is set to The distance from the first reflecting surface to the inner peripheral surface of the cylindrical body is set based on a value obtained by subtracting the focal length of the sensor head.

  In such a configuration, it is possible to perform the inspection of the end face of the cylinder and the inspection of the inner periphery of the cylinder using the same inspection apparatus.

  According to the present invention, it is possible to suppress a significant increase in product cost without increasing the size of the apparatus, and to easily cope with cylinders having different inner diameters, and to greatly increase the inspection time and setup time. Not only can the reduction be realized, but the surface of both the inner peripheral surface and the flat surface of the cylindrical body can be inspected continuously or separately by one apparatus, which is convenient.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 10 show a first embodiment of the present invention. FIG. 1 shows a schematic configuration diagram of the surface inspection apparatus.

  Reference numeral 1 in FIG. 1 denotes an inspection station disposed in the middle of the production line. In this inspection station 1, an inner peripheral surface 2a of a cylindrical body 2 as a cylindrical body that is a predetermined processed object. An inspection is performed as to whether or not there is a defect such as a scratch or a foreign substance adhering to the flat surface 2b. The cylindrical body is not necessarily limited to the cylindrical body 2 and can be applied to various cylindrical bodies such as an engine cylinder and a brake cylinder.

  A gantry 3 is disposed above the inspection stage 1a on which the cylindrical body 2 is placed. The gantry 3 is connected to an elevating device (not shown) so as to be movable up and down, and the main body 4 a of the surface inspection device 4 is placed on the gantry 3.

  A rotation sensor slider 5 is housed in the apparatus main body 4a. The rotation sensor slider 5 extends in the vertical direction of the apparatus main body 4a and is supported by slider guide rods 6 fixed at both ends of the apparatus main body 4a so as to be movable in the vertical direction. Further, a feeding drive motor 7 is disposed on the upper part of the apparatus main body 4a, and a slider screw shaft 8 extends downward from the feeding drive motor 7.

  The slider screw shaft 8 extends in parallel with the slider guide rod 6, and the slider screw shaft 8 is screwed into a guide nut 9 fixed to the rotation sensor slider 5. When the slider screw shaft 8 of the feed drive motor 7 is rotated forward, the rotation sensor slider 5 is lowered via the guide nut 9, and when the slider screw shaft 8 is reversed, the rotation sensor slider 5 is raised.

  A rotary cylinder motor 10 is disposed on the rotation sensor slider 5. The base end of the rotary cylinder 11 is connected to the rotary cylinder motor 10. The distal end direction of the rotating cylinder 11 extends downward through a hole 3 a formed in the gantry 3. A mirror 12 as a reflecting member is disposed below the rotating cylinder 11. The rotary cylinder 11 is not necessarily a cylinder, and may be a square cylinder.

  As shown in FIG. 2, the mirror 12 is fixed to a mirror shaft 13 extending in a direction orthogonal to the axis of the rotating cylinder 11, and both ends of the mirror shaft 13 are fixed to the rotating cylinder 11. . The mirror 12 is fixed with respect to the mirror axis 13 so as to have an inclination angle of 45 ° in the tilt direction. Further, the rotating cylinder 11 has a window portion 11a opened in the reflection direction of the mirror surface 12a as the first reflection surface formed on the surface of the mirror 12.

  A cylindrical body 14 is disposed coaxially with the rotating cylinder 11. The base end of the cylindrical body 14 passes through the rotary cylinder 11 and is fixed to the bracket 15. The bracket 15 is supported by a cylindrical body guide rod 16 which is fixed in a vertically extending state with respect to the rotation sensor slider 5 so as to be movable up and down.

  Further, a cylindrical body screw shaft 17 is disposed in parallel with the cylindrical body guide rod 16. The cylindrical body screw shaft 17 extends from a sensor head position adjusting adjustment motor 18 fixed to the rotation sensor slider 5, and the middle of the cylinder body screw shaft 17 is screwed into the bracket 15. The feed drive motor 7 and the sensor head position adjustment adjust motor 18 are operated based on drive signals from the control device 31 (see FIG. 6). The control device 31 is mainly composed of a computer such as a microcomputer.

  As shown in FIG. 4, the sensor head 20 is disposed at the lower end of the cylindrical body 14. As shown in FIG. 5, the sensor head 20 is disposed in a state where the distal end portion of the light projecting fiber 22 and the distal end portion of the light receiving fiber 23 are bound together, and the distal end portions of the fibers 22 and 23 are lenses. It is held by the holding cylinder 21. Further, an objective optical system 24 composed of one or more lenses is held in the lens holding cylinder 21, and the optical axis of the objective optical system 24 is arranged in a state where it matches the axis of the cylindrical body 14. Yes.

  As shown in FIGS. 1 and 3, a cylindrical portion 35 a formed on the top of the cone 35 is fixed to the bottom surface of the gantry 3. The cone 35 may be detachable from the gantry 3 or may be equipped with a plurality of cones 35 having different sizes according to the cylindrical body 2 to be inspected. Further, by making the cone 35 detachable, it is possible to remove it when the surface inspection of the flat surface 2b of the cylindrical body 2 is not required.

  The conical body 35 is disposed coaxially with the rotating cylinder 11 and the cylindrical body 14, and the inner diameter of the opening end thereof is larger than the outer diameter of the cylindrical body 2 to be inspected, and the upper inner diameter is cylindrical. It is formed smaller than the inner diameter of the body 2.

  Further, a mirror surface 35 b as a second reflecting surface is formed on the inner surface of the cone 35. The mirror surface 35b is opposed to the mirror surface 12a with a parallel tilt angle, that is, a 45 ° tilt angle. Accordingly, the inspection light emitted from the objective optical system 24 is reflected in the 90 ° direction by the mirror surface 12a, and when reaching the mirror surface 35b, is reflected by the mirror surface 35b and is perpendicular to the flat surface 2b of the cylindrical body 2. Is irradiated.

By the way, since the focal distance d set by the objective optical system 24 is constant, the distance from the objective optical system 24 to the mirror surface 12a (hereinafter referred to as “optical system-mirror distance”) is dm, and from the mirror surface 12a. The distance to the mirror surface 35b (hereinafter referred to as “the distance between the mirror and the cone”) is dw, and the distance from the mirror surface 35b to the flat surface 2b of the cylindrical body 2 (hereinafter referred to as “the distance between the cone and the flat surface”). Is set to dh, the distance d from the tip of the objective optical system 24 to the flat surface 2b of the cylindrical body 2 is always d = dm + dw + dh = constant (1)
It is necessary to maintain the relationship.

  However, the value of dm + dw + dh does not necessarily coincide with the focal length d set by the objective optical system 24. Assuming that there is no aberration of the objective optical system 24, when the value of dm + dw + dh exactly coincides with the focal length d, when the light emitted from the light projecting fiber 22 is regularly reflected, all returns to the light projecting fiber 22. End up. Therefore, it is necessary that the focal region of the light emitted from the light projecting fiber 22 and the region of the reflected light focused on the light receiving fiber 23 partially overlap. For this reason, when the aberration of the objective optical system 24 is small, it is preferable to set the value of dm + dw + dh so that it slightly deviates from the focal length d. The deviation amount with respect to the focal point d is set so that the overlapping area has an appropriate size for the target detection accuracy.

  As shown in FIG. 10, when the tilt angle θ of the mirror surface 12a and the mirror surface 35b is 45 °, dw + dh is always constant even when the rotary cylinder 11 is moved up and down. dm is always constant regardless of the vertical movement of the cylindrical body 2. In addition, this form is applicable even if there exists inclination-angle (theta) of both the reflective surfaces 12a and 35b other than 45 degrees.

That is, the thickness of the flat surface 2b is dt, and the distance between the mirror and the cone dw is dm ′ (when the mirror-cone distance dw is at the inner peripheral end of the flat surface 2b, as shown in FIG. In the case of the initial position), the distance dm between the optical system and the mirror is synchronized with the lowering of the rotary cylinder 11,
dm = dm′−dt · tan (90−2θ) (1 ′)
It is possible to keep the focal distance d constant by moving with.

  However, even in this case, since the inclination angle θ of both the reflection surfaces 12a and 35a is a fixed value, the data input during the surface inspection is when the inclination angle θ of the reflection surfaces 12a and 35b is 45 °. Is the same.

Further, the surface inspection apparatus 4 according to the present embodiment can perform the surface inspection of the inner peripheral surface 2 a following the surface inspection of the flat surface 2 b of the cylindrical body 2. FIG. 1 also shows a state in which the tip of the rotating cylinder 11 is inserted through the inner periphery of the cylindrical body 2. As shown in the figure, the focal length d in this case is
d = dm + dw
It becomes. In this case, since the mirror-cone distance dw is constant, the optical system-mirror distance dm is also constant.

  On the other hand, as shown in FIG. 6, the rear ends of the fibers 22 and 23 are respectively connected to a light source unit 26 and an inspection calculation unit 27 provided in the calculation circuit unit 25. The light source unit 26 is provided with an LD driver 26a and a laser diode 26b that is issued by a drive signal from the LD driver 26a. The incident end of the light projecting fiber 22 is opposed to the laser diode 26b. The light source of the light projecting fiber 22 is not limited to the laser diode 26b, and a light emitting diode or the like can also be used.

  Further, the inspection calculation unit 27 is provided with a photo sensor 27a provided at the output end of the light receiving fiber 23, and one input end of the comparison circuit 27c is connected to the photo sensor 27a via the amplification circuit 27b. A threshold value setting circuit 27d is connected to the other input terminal of the comparison circuit 27c. The comparison circuit 27c compares the voltage value Vo, which is output from the amplification circuit 27b and indicates the amount of reflected light received and photoelectrically converted by the photosensor 27a, with the threshold value output from the threshold setting circuit 27d. The result is output to the control device 31.

  As shown in FIG. 7, the threshold value has a high level LHi and a low level LLi, and the comparison circuit 27c compares the voltage value Vo indicating the amount of reflected light with the threshold values LHi and LLi, thereby generating a cylinder. It is inspected whether the flat surface 2 b and the inner peripheral surface 2 a of the body 2 are scratched or foreign matter is mixed in, and the result is output to the control device 31.

  In the control device 31, based on the comparison result in the comparison circuit 27 c, the drive signal is monitored, printer, etc. for performing necessary display, printing, etc. on the surface of the flat surface 2 b and the inner peripheral surface 2 a of the cylindrical body 2 or foreign matter. The data is output to output means (not shown) or the like and the current data is stored.

  Next, the effect | action of this form by such a structure is demonstrated. The cylindrical body 2 is placed on the inspection stage 1 a of the inspection station 1, and the axial center of the cylindrical body 2 is fixed so as to coincide with the axial center of the rotating cylinder 11 of the surface inspection apparatus 4.

  Next, the gantry 3 on which the apparatus main body 4a is placed is lowered, and the distance L between the flat surface 2b on the upper surface side of the cylindrical body 2 and the lower end of the cone 35 fixed to the gantry 3 is determined in advance. Set to an interval (for example, 5 mm). In addition, since the axis of the cone 35 is fixed in a state where it coincides with the axis of the rotary cylinder 11, the axis of the cone 35 is coincident with the axis of the cylinder 2.

  In this state, the rotation sensor slider 5 provided in the surface inspection apparatus 4 is raised, and the lower end of the rotary cylinder 11 that moves together with the rotation sensor slider 5 waits at least near the bottom surface of the gantry 3. Yes.

  On the other hand, the control device 31 is in an input waiting state for the inner diameter data (2dw) of the cylindrical body 2, and a screen for requesting input of the inner diameter data is displayed on the monitor. Then, when the inner diameter data 2dw of the cylindrical body 2 is input in step S1 of the inspection start position setting routine shown in FIG. 8, the process proceeds to step S2. It is assumed that data regarding the cone 35 (inclination angle θ, inner diameter at the lower end, distance L between the lower end and the flat surface 2b, etc.) are input in advance.

  In step S2, when the inner diameter data (2dw) of the cylindrical body 2 is inputted, the distance dh between the cone and the flat surface is calculated based on the data concerning the cone 35 inputted in advance.

Next, the process proceeds to step S3, and the initial position of the optical system / mirror distance dm is determined based on the equation (1) or (1 ′).
dm ← d− (dw + dh)
Or dm ← dt · tan (90-2θ)
Calculate from

  In step S4, a drive signal corresponding to the distance dh between the cone and the flat surface is output to the feed drive motor 7, and between the optical system and the mirror to the sensor head position adjustment adjust motor 18. A drive signal corresponding to the distance dm is output, and the routine ends. The inspection start position setting routine may be executed for each cylindrical body 2 installed on the inspection stage 1a, but may be executed for each production lot.

  The feed drive motor 7 rotates the slider screw shaft 8 by a predetermined amount based on a drive signal output from the control device 31 and corresponding to the cone / flat surface distance dh. When the slider screw shaft 8 is rotated, the rotation sensor slider 5 fixed with a guide nut 9 into which the slider screw shaft 8 is screwed is lowered while being supported by the slider guide rod 6.

  As a result, the rotary cylinder 11 and the cylindrical body 14 fixed to the rotation sensor slider 5 are integrally lowered, and the reflection position of the mirror 12 fixed to the lower portion of the rotary cylinder 11 is changed to a cone. -Set to the initial position of the flat surface distance dh. At this time, the mirror-cone distance dw is also set to the initial position.

  On the other hand, the adjusting motor 18 for adjusting the sensor head position causes the cylindrical body screw shaft 17 to rotate forward or reverse by a predetermined amount based on the drive signal output from the control device 31 and corresponding to the optical system / mirror distance dm. . When the cylindrical body screw shaft 17 rotates, the bracket 15 descends or rises while being supported by the cylindrical body guide rod 16, and the cylindrical body 14 fixed to the lower surface of the bracket 15 moves in the same direction. Move together.

  As a result, an optical system-mirror distance dm, which is the distance between the objective optical system 24 of the sensor head 20 provided at the lower end of the cylindrical body 14 and the mirror 12, is set.

  Next, both the rotary cylinder motor 10 and the feed drive motor 7 are rotated at a constant speed in the forward rotation direction. When the rotary cylinder motor 10 rotates, the rotary cylinder 11 rotates at a constant speed, and the mirror 12 fixed to the lower end of the rotary cylinder 11 via the mirror shaft 13 rotates in the same direction. When the feed drive motor 7 rotates, the rotation sensor slider 5 moves along the slider guide rod 6 via the guide nut 9 screwed into the slider screw shaft 8 of the feed drive motor 7. The rotating cylinder 11 and the cylindrical body 14 held by the rotation sensor slider 5 are moved integrally. As a result, the rotating cylinder 11 descends at a pitch set by the rotational speed of the feed drive motor 7 while rotating at a constant speed.

  Inspection light is emitted from the laser diode 26b of the light source unit 26 provided in the arithmetic circuit unit 25 from the tip of the light projecting fiber 22 bundled with the sensor head 20 provided at the lower end of the cylindrical body 14, This inspection light is reflected through the objective optical system 24 by the mirror surface 12a of the mirror 12 in the 90 ° direction. The inspection light reflected by the mirror surface 12a is applied to the mirror surface 35b formed on the inner surface of the cone 35 at a substantially right angle, and the inspection light reflected from the mirror surface 35b is a flat surface of the cylindrical body 2. Irradiated substantially at right angles to 2b.

  Since the mirror 12 rotates integrally with the cylindrical body 14 and the cylindrical body 14 descends at a constant pitch, the inspection light applied to the mirror surface 35b of the conical body 35 as shown in FIG. Descends in a spiral with a constant pitch. Accordingly, the inspection light reflected from the mirror surface 35b scans on the flat surface 2b of the cylindrical body 2 in a spiral manner at a constant pitch.

  This pitch is determined by the rotational speed of the rotary cylinder motor 10 and the feed amount of the feed drive motor 7. For example, when the accuracy of detecting a scratch having a size of 0.3 mm or more is required, the rotary cylinder 11 is set to a feed amount of 0.15 mm per rotation. Therefore, when the rotating cylinder 11 is rotated at 3000 rpm, the rotating cylinder 11 may be sent out at a speed of 7.5 mm per second.

  Since the inspection light is irradiated to the flat surface 2 b of the cylindrical body 2 at a substantially right angle, the reflected light reaches the objective optical system 24 through the same path as the forward path, and passes through the objective optical system 24 to receive the light receiving fiber 23. Is incident on. The reflected light incident on the light receiving fiber 23 is received by a photosensor 27 a provided in the inspection calculation unit 27 of the calculation circuit unit 25. The reflected light received by the photosensor 27a is photoelectrically converted, amplified to a predetermined level by the amplification circuit 27b, and then output to the comparison circuit 27c.

  The reflected light from the flat surface 2b of the cylindrical body 2 is scattered when there is a scratch on the flat surface 2b. Therefore, the amount of light received by the photosensor 27a decreases, and the voltage value Vo becomes low. On the other hand, if foreign matter adheres during processing or conveyance, the reflected light from the foreign matter may be reflected more strongly than the reflected light from the normal flat surface 2b. A voltage value Vo is detected.

  The comparison circuit 27c compares the voltage value Vo input via the amplifier circuit 27b with the low level LLo and high level LHi threshold values output from the threshold setting circuit 27d. The threshold values LLi and LHi are values set by predicting experimental values or the like based on the amount of light reflected from the flat surface 2b of the cylindrical body 2 and indicating the presence of scratches or foreign matter on the surface. is there.

  Then, as shown in FIG. 7, the comparison circuit 27c outputs an L signal when the voltage value Vo falls within both threshold values LLi and LHi, and the voltage value Vo is lower than the low level LLi or higher. When it is equal to or higher than LHi, an H signal is output. Note that the data comparison may be performed in the control device using another method, for example, an image processing technique or the like.

  Based on the signal from the comparison circuit 27c, the control device 31 outputs necessary information for scratches on the flat surface 2b of the cylindrical body 2 or adhesion of foreign matter to a monitor, a printer, etc., and stores it in a predetermined manner.

  When the surface inspection of the flat surface 2b is completed, the operations of the rotary cylinder motor 10 and the feed drive motor 7 are temporarily stopped. The timing for ending the surface inspection of the flat surface 2b is based on the cone / flat surface distance dh calculated in step S2 of the above-described inspection start position setting routine and the downward movement amount of the rotary cylinder 11. Can be determined.

  On the other hand, when the surface inspection of the flat surface 2b is completed, the surface inspection device 4 enters a state of waiting for an instruction as to whether or not to inspect the inner peripheral surface 2a of the cylindrical body 2, and whether or not the surface inspection is continued on the monitor. Is displayed, and the inner peripheral surface inspection routine shown in FIG. 9 is started.

  Then, in step S11, the process waits for an input as to whether or not to select the inspection continuation. When the inspection continuation is selected, the process proceeds to step S12.

Proceeding to step S12, based on the inner diameter data (2dw) input in step S1 of the inspection start position setting routine described above,
dm = d−dw (2)
From the above, the distance dm between the optical system and the mirror is calculated.

  In step S13, a drive signal corresponding to the optical system / mirror distance dm is output to the sensor head position adjusting adjust motor 18, and the routine is terminated.

  In the sensor head position adjusting adjust motor 18, the cylindrical body 14 is operated based on the drive signal corresponding to the optical system / mirror distance dm output from the control device 31, and the objective optical system 24 and the mirror 12 are moved. The distance dm between the optical system and the mirror, which is the distance between them, is set.

  Thereafter, the rotating cylinder motor 10 and the feed driving motor 7 are rotated again, and the inspection light emitted from the laser diode 26b is substantially perpendicular to the inner peripheral surface 2a of the cylindrical body 2 as in the surface inspection of the flat surface 2b described above. The inner peripheral surface 2a is scanned in a spiral manner at a constant pitch.

  Then, the reflected light from the inner peripheral surface 2a of the cylindrical body 2 is received by the photosensor 27a, and the comparison circuit 27c compares the amount of light received by the photosensor 27a with the threshold values LLi and LHi. The presence or absence of flaws on the peripheral surface 2a or foreign matter adhesion is inspected.

  Thus, in this embodiment, the flat surface 2b and the inner peripheral surface 2a of the cylindrical body 2 that is the inspection object can be continuously inspected using one surface inspection device 4, so that Efficiency is good.

  Moreover, since the flat surface 2b and the inner peripheral surface 2a of the cylindrical body 2 can be separately inspected using one surface inspection device 4, it is easy to use.

  Furthermore, since the cylindrical body 2 having a different inner diameter can be applied by adjusting the distance dm between the optical system and the mirror according to the inner diameter, complicated work such as exchanging the lens becomes unnecessary. Good handling. Moreover, since it can respond also to all cylindrical bodies having different inner diameters, it is possible to realize a significant reduction in setup time, high work efficiency, and a reduction in product cost.

  Further, since the flat surface 2b and the inner peripheral surface 2a of the cylindrical body 2 are spirally scanned to inspect for the presence or absence of a defective portion, the entire flat surface 2b and the upper end of the inner peripheral surface 2a are inspected. The bottom end can be inspected continuously and the workability is good. In this case, if the feed amount of the feed drive motor 7 is set at a lower speed, the defective portions of the flat surface 2b and the inner peripheral surface 2a can be inspected more closely.

  FIG. 11 is a schematic view of a surface inspection apparatus according to the second embodiment of the present invention. In the first embodiment described above, the surface inspection of the flat surface 2b is performed with the cylindrical body 2 set on the inspection stage 1a. However, in this embodiment, the flat surface 2c on the bottom surface side of the cylindrical body 2 is also continuous. It is possible to perform surface inspection.

  In the surface inspection apparatus 4 according to this embodiment, a conical body 41 whose opening end face is directed upward is fixed on the inspection stage 1a. The conical body 41 has the same configuration as the conical body 35 facing upward, and therefore, a mirror surface 41a as a second reflecting surface is formed on the inner peripheral surface.

  In the surface inspection, the cylindrical body 2 is provided above the cone 41. In the present embodiment, as shown in the figure, the outer periphery 2d of the cylindrical body 2 is fixed in a state of being gripped by a gripper 42 provided at the tip of the robot arm or the like as a means for mounting the cylindrical body 2 on the cone 41. .

  Next, the rotary cylinder 11 of the surface inspection apparatus 4 is made to face the axial center of the cylindrical body 2, and the flat surface 2b on the upper surface side of the cylindrical body 2 and the inner peripheral surface 2a are spiraled by the same operation as in the first embodiment. Scan the surface to perform surface inspection.

  When the inspection light reaches the lower end of the inner peripheral surface 2a, the operations of the feed drive motor 7 and the rotary cylinder motor 10 (see FIG. 1) are temporarily stopped.

  Next, the initial position of the optical system / mirror distance dm is calculated based on the above-described formula (1) or (1 ′), and the sensor head position adjusting adjust motor 18 is driven to set the optical system / mirror distance. Set the distance dm.

  Thereafter, the rotating cylinder motor 10 and the feed drive motor 7 are rotated again, and the inspection light emitted from the laser diode 26b is transmitted through the mirror surface 12a of the mirror 12 as in the surface inspection of the flat surface 2b described above. Reflected in the direction of 90 °, irradiated through the mirror surface 41a formed on the inner surface of the cone 41 at a substantially right angle to the flat surface 2c of the cone 2, and the reflected light is received by the photosensor 27a, In the same manner as described above, the comparison circuit 27c compares the amount of light received by the photosensor 27a with the thresholds LLi and LHi, and inspects the inner peripheral surface 2a of the cylindrical body 2 for the presence of flaws or foreign matter adhesion.

  Thus, in this embodiment, the single surface inspection device 4 can continuously inspect the flat surface 2b on the upper surface side, the inner peripheral surface 2a, and the flat surface 2c on the bottom surface side of the cylindrical body 2. The surface inspection can be performed efficiently.

  The surface inspection apparatus of the present invention can be used as an apparatus for optically inspecting a defective portion on an inner peripheral surface of a cylindrical shape such as an engine cylinder, a brake cylinder, a compressor cylinder, and other various operating cylinders. .

  The shape of the inspection object is not limited to the cylindrical body 2, but can be applied to various objects such as an elliptical cylindrical body, a conical cylindrical body, and a container-shaped cylindrical body whose bottom is closed.

  Alternatively, the surface inspection may be performed by fixing the apparatus main body 4a to the lower side of the inspection stage 1a and by facing the cylindrical body 2 from above. Further, the mirror 12 may be fixed and the inspection target such as the cylindrical body 2 may be rotated to inspect the surface.

Schematic configuration diagram of a surface inspection apparatus according to the first embodiment FIG. 1 is a right side sectional view of the rotating cylinder shown in FIG. Top view of the cone Same as above, enlarged sectional view of sensor head Same as above, VV sectional view of FIG. Same configuration diagram of arithmetic circuit Waveform diagram showing the relationship between the voltage value detected by the photosensor and the threshold value The flowchart showing the inspection start position setting routine Same as above, flowchart showing inner surface inspection routine Explanatory drawing which shows the procedure which calculates the distance from an objective optical system to a 1st reflective surface similarly Schematic configuration diagram of a surface inspection apparatus according to the second embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... Inspection stage 2 ... Cylindrical body 2a ... Inner peripheral surface 2b, 2c ... Flat surface 4 ... Surface inspection apparatus 4a ... Apparatus main body 11 ... Rotating cylinder 12 ... Mirror 12a ... Mirror surface 14 ... Cylindrical body 20 ... Sensor head 35 ... Cone 35b ... mirror surface d ... focal length dh ... distance between cone and flat surface dm ... distance between optical system and mirror dw ... distance between mirror and cone

Claims (6)

In the surface inspection apparatus that irradiates the flat surface formed on the end surface of the cylindrical body with inspection light and inspects whether there is a defect on the flat surface based on the change in the amount of reflected light.
A sensor head that emits the inspection light in the axial direction of the cylindrical body is provided,
On the optical axis of the sensor head, a first reflecting surface that reflects the inspection light in a direction intersecting the optical axis and rotates relative to the cylindrical body is disposed.
Disposing a second reflecting surface parallel to the first reflecting surface in the reflecting direction of the first reflecting surface, and facing the second reflecting surface to the flat surface;
The distance between the sensor head and the first reflecting surface is defined as the distance from the first reflecting surface to the second reflecting surface and the distance from the second reflecting surface to the flat surface as the sensor head. The surface inspection apparatus is set based on a value obtained by subtracting from the focal length.   2. The surface inspection apparatus according to claim 1, wherein the second reflecting surfaces are respectively opposed to the flat surfaces formed on both end surfaces of the cylindrical body. 3. The second reflecting surface is formed on an inner surface of a cone, and is arranged in a state where an axis of the cone coincides with an optical axis of the sensor head. The surface inspection apparatus described. The first reflecting surface is fixed to a rotating cylinder that is packaged on the sensor head,
The surface inspection apparatus according to claim 1, wherein the first reflecting member is rotated by rotation of the rotating cylinder. The first reflecting surface is fixed to a rotating cylinder that is packaged on the sensor head,
The first reflecting surface is rotated by the rotation of the rotating cylinder, and
The sensor head is fixed to a cylindrical body disposed coaxially with the rotating cylinder,
5. The surface inspection apparatus according to claim 4, wherein the flat surface is helically scanned by integrally moving the rotating cylinder and the cylindrical body in the axial direction. The first reflecting surface is inserted into the cylindrical body and moved in the axial direction while rotating relative to the cylindrical body, thereby inspecting whether there is a defect on the inner peripheral surface of the cylindrical body. Has a mechanism to
In that case, the distance between the sensor head and the first reflecting surface is based on a value obtained by subtracting the distance from the first reflecting surface to the inner peripheral surface of the cylindrical body from the focal length of the sensor head. The surface inspection apparatus according to claim 1, wherein the surface inspection apparatus is set.

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