JP2007315805A - Surface inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface inspection device capable of elongating an inspection rod, without degrading inspection quality and which is capable of rotating the inspection at a high speed. <P>SOLUTION: The surface inspection device 1 is equipped with the inspection rod 21 which can be inserted in a hole 100a of an inspection target 100, a reflecting mirror 219 provided to the inspection rod 21 and a support table 22 for supporting the inspection rod 21. The inspection rod 21 has a base part 211 attached to the support table 22, a rotary head 212 attached to the base part 211, in a state of being rotatable about an axial line CL, while holding the reflecting mirror 219. The rotary head 212 is rotated, by blowing air against the impeller 221 provided to the rotary head 212. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface inspection apparatus for inspecting defects such as foreign matter and scratches present on the inner peripheral surface of a hole of an inspection object in which a hole is formed.

  As a surface inspection device that inspects the inner peripheral surface of an object to be inspected, for example, a cylinder liner or a cylinder bore of an internal combustion engine, the inspection light is projected onto the inner peripheral surface, and the reflected light from the inner peripheral surface By inserting a rod-shaped inspection rod configured to receive the hole into the hole, and then moving the inspection rod around the axis extending in the longitudinal direction, the rod moves forward and backward relative to the object to be inspected. There is one that can inspect the inner peripheral surface (see, for example, Patent Document 1).

JP-A-11-281582

  In such an inspection apparatus, the longer the length of the inspection rod is, the deeper the inner peripheral surface of the hole can be inspected. However, when the entire inspection rod is rotated, the longer the inspection rod is, the more unstable the rotation becomes and the inspection accuracy deteriorates. The rotation can be stabilized by increasing the outer diameter of the inspection rod and increasing the rigidity. However, if the inspection rod becomes thicker than the hole diameter of the object to be inspected, the inspection becomes impossible, and the inspection targets that can be inspected are limited. Further, although the rotation of the inspection rod can be stabilized by increasing the processing accuracy of each part, the processing cost increases accordingly. Under these circumstances, in order to ensure the required inspection accuracy, the rotation speed of the inspection rod must be suppressed, resulting in a prolonged inspection time. Japanese Patent Application Laid-Open No. 2004-228561 has a description that it can be configured to rotate only the optical path changing means provided at the tip of the inspection rod, but there is no explicit structure for realizing the rotation.

  Therefore, an object of the present invention is to provide a surface inspection apparatus that can lengthen an inspection rod and rotate it at high speed without deteriorating inspection accuracy.

  The surface inspection apparatus (1) of the present invention includes an inspection rod (21) that can be inserted into the hole of the object to be inspected (100) in which the hole (100a) is formed, and the inspection rod. An optical path changing member (219) that changes the traveling direction of the inspection light so that the inspection light is projected onto the inner peripheral surface and changes the traveling direction of the reflected light of the inspection light projected onto the inner peripheral surface of the hole. ) And support means (22) for supporting the inspection rod, the inspection rod holding a base (211) attached to the support means and the length of the inspection rod while holding the optical path changing member And a member holding part (212) attached to the base in a state of being rotatable around an axial line (CL) extending in the direction, and rotating the member holding part around the axis by using an air flow Driving means (221, 222, 223 By further comprising, for solving the above problems.

  According to this inspection device, by utilizing the air flow, only the member holding portion can be rotated without rotating the base portion of the inspection rod. Even when the entire length of the inspection rod is increased by increasing the length of the base portion, the increase in the size does not affect the rotation of the member holding portion. Therefore, even if the rotation speed of the member holding portion is increased, the inspection accuracy is not deteriorated. In particular, the clearance between the inner peripheral surface of the hole and the inspection rod may be reduced due to the relationship with the hole diameter of the object to be inspected. Even in such a case, since the swing of the member holding portion is small, the risk that the inspection rod comes into contact with the inner peripheral surface is reduced. Therefore, safety is improved. In addition, since the member holding portion is rotationally driven by the air flow, it is possible to easily realize the use of the air flow to blow off foreign matters or the like adhering to the inner peripheral surface of the inspection target before starting the inspection. Therefore, it is possible to prevent the foreign matter adhering to the inspection surface from being erroneously detected as a defect. In addition, since the rotating portion is relatively small as compared with the aspect in which the entire inspection rod is rotated, the opportunity for an operator or the like to erroneously access the rotating portion is reduced. Therefore, the cost required for safety measures for preventing such erroneous access can be reduced.

  The rotation drive means according to the present invention may be in any form, but as one aspect thereof, the rotation drive means uses a blown air to rotate the member holding portion around the axis. You may provide the rotational force generation means (221) to generate, and the ventilation means (222, 223) which blows air with respect to the said rotational force generation means. When the optical path changing means is configured to generate a rotational force related to the rotation axis that rotates the member holding portion in one direction by blowing air to the optical path changing means, the optical path changing means is set to the rotational force. You may make it function as a generating means. Moreover, the impeller (221) attached to the said member holding part may be provided as a rotational force generation means. In this case, the efficiency of the rotational force can be freely adjusted by appropriately designing the shape of the impeller.

  The air blowing means according to the present invention may be realized in any form, but as one aspect thereof, the base portion of the inspection rod is configured in a hollow shape, and the air blowing means is an air pressurizing unit. You may provide a pressure means (223) and the ventilation path (222) which is provided inside the said base and guides the air pressurized by the said pressurization means to the said rotational force generation means. In this case, since the air passage that guides the pressurized air is provided inside the base portion, the structure is compact and the air passage does not interfere with the inspection as compared with the aspect in which the air passage is arranged around the inspection rod. There are advantages.

  In one aspect of the present invention, the moving means (25) for linearly moving the inspection object or the support means so that the inspection rod moves relative to the inspection object along the axial direction; The rotational position detecting means (31) for detecting the rotational position of the member holding part, and the rotational position so that the ratio between the rotational speed of the member holding part and the relative speed of the inspection rod with respect to the inspection object is constant. You may further provide the movement control means (3) which controls operation | movement of the said movement means based on the detection result of a detection means. In this case, even if the rotational speed of the member holding portion varies, the relative speed (feeding speed) of the inspection rod with respect to the object to be inspected is controlled according to the variation. The ratio is kept constant. Therefore, even if the member holding part is accelerating or decelerating, the surface inspection can be performed with the required inspection accuracy. For this reason, it is not necessary to stop the movement of the inspection rod until the fluctuation of the rotation speed of the member holding portion falls within the allowable range, so that the inspection time required for inspection of one inspection object can be shortened accordingly.

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

  As described above, according to the present invention, since only the member holding portion can be rotated, the inspection accuracy is not deteriorated even if the rotation speed of the member holding portion is increased. In addition, since the member holding portion is driven to rotate by the air flow, it is possible to easily blow off foreign matter adhering to the inner peripheral surface of the inspected object using the air flow before starting the inspection. Can be prevented from being erroneously detected as a defect.

  FIG. 1 shows a schematic configuration of a surface inspection apparatus according to an embodiment of the present invention. The surface inspection apparatus 1 is an apparatus suitable for surface inspection of the inner peripheral surface of the hole 100a of the object 100 to be inspected, such as a cylinder liner or a cylinder bore of an internal combustion engine. A control unit 3 that controls the operation of the mechanism 2 and an information processing unit 4 that processes information obtained by the inspection mechanism 2 are provided. The inspection mechanism 2 projects inspection light onto the inner peripheral surface of the hole 100a of the stationary inspection object 100 based on a command from the control unit 3, and acquires the amount of received reflected light (intensity) corresponding to the inspection area. . The intensity of the reflected light acquired by the inspection mechanism 2 is sent to the information processing unit 4, and the information processing unit 4 generates a two-dimensional image based on the intensity by a predetermined process, and based on the two-dimensional image, a cast hole or the like The presence or absence of defects is determined and the inspection result is output. The determination performed by the information processing unit 4 is performed by determining whether or not the dark part corresponding to the defect exists in the two-dimensional image, but the details of the process are not related to the gist of the present invention, and thus the description thereof is omitted. To do.

  The inspection mechanism 2 includes an inspection rod 21 that is inserted into the hole 100a of the object 100 to be inspected and acquires information about the inner peripheral surface of the hole 100a, and a support table 22 that supports the inspection rod 21. . The support table 22 is attached to the base 24 so as to be linearly moved while being guided by a pair of guide portions 23 extending along the longitudinal direction of the inspection rod 21, and the inspection rod 21 is linearly attached to the base 24 together with the support table 22. A linear moving mechanism 25 for moving is provided.

  The linear movement mechanism 25 includes a conversion mechanism 27 that converts the rotational motion of the electric motor 26 into a linear motion, and the support table 22 is driven by the electric motor 26 via the conversion mechanism 27. The conversion mechanism 27 is configured by combining a ball screw 28a provided on the rotation shaft 28 of the electric motor 26 and a nut 29a provided on an arm 29 connected to the support table 22 with a ball (not shown) interposed therebetween. The Thereby, by controlling the operation of the electric motor 26 of the linear movement mechanism 25, the inspection rod 21 can be arbitrarily advanced and retracted along the axis CL extending in the longitudinal direction. Instead of providing the electric motor 26 and the conversion mechanism 27 as the linear movement mechanism 25, the linear movement mechanism 25 may be implemented by a linear motor or the like.

  As shown in FIG. 2, the inspection rod 21 is positioned at the distal end portion of the inspection rod 21 so as to close the hollow cylindrical base portion 211 attached to the support table 22 and one opening of the base portion 211. The cap-shaped rotary head 212 is combined with each other. In the internal space of the base 211, a light projecting / receiving device 213 for projecting the inspection light and receiving the reflected light is provided. The light projecting / receiving device 213 includes an optical fiber group 214 in which a light projecting fiber 214a located at the center and a plurality of light receiving fibers 214b arranged around the light projecting fiber 214a are bundled. The optical fiber group 214 is held by a fiber holding cylinder 215 inserted in the internal space of the base 211. The light projecting fiber 214a and the light receiving fiber 214b are aligned so that one end face thereof faces the direction of the axis CL. As shown in FIG. 1, a laser diode 215 as a light source for inspection light is provided at the other end of the light projecting fiber 214a, and a photodetector that outputs a signal corresponding to the amount of received light at the other end of the light receiving fiber 214b. 216 are connected to each other. The signal from the photodetector 216 is sent to the information processing unit 4.

  As shown in FIG. 2, the rotary head 212 is attached to the base 211 via a bearing 217 so as to be rotatable about the axis CL. An inspection window 212a is provided on the side wall of the rotary head 212 so that the inspection light R1 can be projected onto the inner peripheral surface of the hole 100a of the inspection object 100 and the reflected light of the inspection light reflected by the inner peripheral surface can be received. It has been. In the internal space of the rotary head 212, a reflecting mirror 219 held by the rotary head 212 with a holding member 218 interposed is provided so as to form an angle of about 45 ° with respect to the axis CL. The reflecting mirror 219 changes the traveling direction so that the inspection light R1 from the light projecting fiber 214a can be guided to the inspection window 212a, and guides the reflected light R2 received through the inspection window 212a. The direction of travel can be changed so that A condensing lens 220 that condenses the reflected light R2 is provided between the light receiving fiber 214b and the reflecting mirror 219.

  As shown in FIG. 3, the inspection mechanism 2 includes an impeller 221 that generates a rotational force that rotates the rotary head 212 around the axis CL. The impeller 221 is attached to the ceiling of the rotary head 212 so as to surround the reflector 219. On the side wall of the rotary head 212, a plurality of air jets 212 b that open to the outside are provided along the circumferential direction of the impeller 221. A ventilation passage 222 that opens toward the impeller 221 is formed between the inner peripheral surface of the base 211 and the outer peripheral surface of the fiber holding cylinder 215. As shown in FIG. 1, a supply passage 224 for introducing air pressurized by an air pump 223 is connected to the air passage 222. Air filtered by the air filter 225 is supplied to the air pump 223. When the air pump 223 is activated, air is blown to the impeller 221 through the air passage 222 as shown by the arrow in FIG. 2, and the air is discharged from the air jet 212b. Thereby, the rotary head 212 is rotationally driven around the axis line CL.

  As shown in FIG. 2, the inspection mechanism 2 includes an encoder 31 that outputs a pulse signal corresponding to the rotational position of the rotary head 212. The encoder 31 is attached to the lower surface of the rotary head 212, rotates integrally, and has a disc 31a in which a plurality of detection holes (not shown) arranged at predetermined intervals along the circumferential direction are formed. And a pickup 31b that generates a pulse corresponding to the position of the detection hole. A pulse signal from the encoder 31 is sent to the control unit 3. When the control unit 3 receives a predetermined inspection start signal, the control unit 3 operates the air pump 223 to rotate the rotary head 212. The operation of the electric motor 26 is controlled based on the pulse signal from the encoder 31 with the air pump 223 activated.

  In the case where the rotational speed of the rotary head 212 and the movement speed (feed speed) of the inspection rod 21 in the axial direction CL by the linear movement mechanism 25 are controlled separately, the fluctuation of the rotational speed of the rotary head 212 is within an allowable range. If the inspection rod 21 is not moved in a state where it is within the range, the required inspection accuracy cannot be ensured. Further, in this case, even if the inspection rod 21 is moved at a predetermined feed speed in a state where the fluctuation of the rotational speed is within the allowable range, strictly speaking, the fluctuation is reflected in the inspection result.

  On the other hand, in the case of the surface inspection apparatus 1, even if the rotation speed of the rotary head 212 fluctuates, the feed speed is controlled according to the fluctuation, so the ratio between the rotation speed and the feed speed is kept constant. It is. For this reason, for example, even when the rotary head 212 is accelerating or decelerating, the surface inspection can be performed with the required inspection accuracy. That is, since it is not necessary to stop the movement of the inspection rod 21 until the fluctuation of the rotational speed falls within the allowable range, the inspection time required for the inspection of one inspection object 100 can be shortened accordingly. Further, even when the fluctuation of the rotation speed of the rotary head 212 is within the allowable range, the fluctuation does not affect the inspection result, so that the accuracy of the inspection result is improved. Since the surface inspection apparatus 1 rotationally drives the rotary head 212 using the air flow, it is not impossible, but it is relatively difficult to accurately control the rotation speed by manipulating the air flow rate. However, by executing such control, the inspection can be executed even if the rotational speed of the rotary head 212 is not accurately controlled, that is, as long as the rotary head 212 is rotated. Inspection accuracy can be sufficiently secured. Therefore, the control executed by the control unit 3 is suitable for the surface inspection apparatus 1.

  In the above embodiment, the reflecting mirror 219 is the optical path changing member according to the present invention, the support table 22 is the supporting means according to the present invention, the rotary head 212 is the member holding portion according to the present invention, and the impeller 221 is the present invention. In the rotational force generating means, the air pump 223 is the pressurizing means according to the present invention, the encoder 31 is the rotational position detecting means according to the present invention, the control unit 3 is the movement control means according to the present invention, and the linear moving mechanism 25 is Each corresponds to the moving means of the present invention. The blowing passage 222, the supply passage 224, and the air pump 223 constitute the blowing means according to the present invention, and these and the impeller 221 constitute the rotational driving means according to the present invention.

  However, this invention is not limited to the form mentioned above, It can implement with a various form within the range of the summary of this invention. In the above embodiment, the stationary inspection object 100 is inspected by moving the support table 22 to which the inspection rod 21 is attached by the linear movement mechanism 25. On the contrary, the inspection rod 21 is stationary. Then, the inspection object 100 may be inspected by moving the inspection object 100. A known moving means similar to the linear moving mechanism 25 may be used as the mechanism for moving the inspection object 100.

  In the above embodiment, the inspection rod 21 is configured by attaching the rotary head 212 to the outside of the base 211. However, the inspection rod 21 may be configured to attach the rotary head 212 to the inside of the base 211. However, if it is assumed that the outer diameter of the base portion 211 is the same, the reflecting mirror 219 can be made larger if the rotary head 212 is attached to the outside of the base portion 211, so that the light receiving range is widened. There is an advantage that can be. Further, the optical path changing member is not limited to the reflecting mirror 219 and can be implemented by a known configuration such as a member capable of exhibiting the same function, such as a prism or a concave reflecting mirror.

  The rotational force generating means is not limited to the above-described form. For example, as shown in FIG. 4, the reflecting mirror 219 functions as the rotational force generating means by forming a flap 219 a extending obliquely from the edge of the reflecting mirror 219. You may let them. In the case of FIG. 4, when the air A is blown onto the reflecting mirror 219, a rotational force related to the axis line CL is generated, and the rotary head 211 can be rotated in one direction.

  In the above embodiment, the air passage 222 is provided in the base 211 and the impeller 221 is provided in the rotary head 212. However, the present invention is not limited to this, and the impeller 221 is disposed outside the rotary head 212 ( For example, the air passage 222 may be provided outside the base portion 211 so that air is blown to the impeller 212.

  The control executed by the control unit 3 is not limited to the above-described form, and the operation of the linear moving mechanism 25 is performed after controlling the rotational speed of the rotary head 212 to be within the allowable range by adjusting the air flow rate. You may make it control. In this case, for example, by providing an electromagnetically driven flow rate adjustment valve in the supply passage 224 and controlling the operation of this adjustment valve, it is possible to realize more accurate control than a mode in which the flow rate is controlled only by the air pump 223. Can do.

The figure which showed schematic structure of the surface inspection apparatus which concerns on one form of this invention. The expanded cross-sectional schematic diagram which expanded the surface inspection apparatus of FIG. 1 partially. The schematic diagram which showed the inside of the rotation head of FIG. 1 toward the upper side of FIG. 1 of the axial direction. The schematic diagram which showed the form which functions a reflecting mirror as a rotational force generation means.

Explanation of symbols

1 Surface inspection device 3 Control unit (movement control means)
21 Inspection rod 22 Support table (support means)
31 Encoder (Rotation position detection means)
100 Inspection object 100a Hole 211 Base 212 Rotating head (member holding part)
219 Reflector (light path changing member)
221 impeller (rotation force generating means)
222 Air passage 223 Air pump (pressurizing means)
CL axis

Claims (5)

An inspection rod that can be inserted into the hole of the inspection object in which a hole is formed, and the traveling direction of the inspection light is changed so that the inspection light is projected onto the inner peripheral surface of the hole. In addition, in the surface inspection apparatus comprising: an optical path changing member that changes a traveling direction of reflected light of the inspection light projected on the inner peripheral surface of the hole; and a support unit that supports the inspection rod.
The inspection rod includes a base portion attached to the support means, and a member holding portion attached to the base portion while being rotatable about an axis extending in the longitudinal direction of the inspection rod while holding the optical path changing member. Have
The surface inspection apparatus further comprising a rotation driving means for rotating the member holding portion around the axis by using a flow of air.   The rotational drive means includes rotational force generating means for generating rotational force for rotating the member holding portion around the axis using the blown air, and blowing means for blowing air to the rotational force generating means. The surface inspection apparatus according to claim 1, further comprising:   The surface inspection apparatus according to claim 2, wherein an impeller attached to the member holding portion is provided as the rotational force generating means. The base of the inspection rod is configured to be hollow,
The blowing unit includes a pressurizing unit that pressurizes air, and a ventilation passage that is provided inside the base and guides the air pressurized by the pressurizing unit to the rotational force generating unit. The surface inspection apparatus according to claim 2 or 3.   A moving means for linearly moving the object to be inspected or the supporting means so that the inspection rod moves relative to the object to be inspected along the axial direction, and a rotational position for detecting a rotational position of the member holding portion. Based on the detection result of the rotation position detection means, the operation of the movement means is performed so that the ratio between the rotation speed of the detection means and the relative speed of the inspection rod with respect to the inspection object is constant. The surface inspection apparatus according to any one of claims 1 to 4, further comprising a movement control means for controlling.

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