JPH01280204A - Surface inspecting device for screw - Google Patents

Abstract

PURPOSE:To reduce the size of the device by converging only light in the photodetection width direction of a tube end detector through an optical system whose light converging function has directivity. CONSTITUTION:When a sample 1 is set a specific position, an elevation mechanism 17 lowers an inspection head 25 and a positioning device consisting of a position detector 11, etc., operates to stop the mechanism 17. Then a turning roller 2 rotates and overscan irradiation light 6 from a projection system 3 enters the optical system 21 whose light converging function has directivity and is converged as shown by an arrow (a) to enter the tube end detector 22. The light is not converged as shown by an arrow 8b, so the irradiation light 6 is cut off at the tube end of the sample 1 and the output of the detector 22 is cased. Said optical system 3 converges only the light in the photodetection width direction of the detector 22 without exerting any influence in the scanning direction of the irradiation light 6 to reduce the photodetection area of the detector 22, thereby reducing the size of the device.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a device for detecting surface defects of screws, and more particularly to a screw surface inspection device that can obtain a synchronization signal for detecting an inspection area of a test object without being affected by the outside diameter of the test object. It is something.

[Conventional technology]

Figures 5 and 6 are, for example, published in Japanese Patent Application Laid-Open No. 62-69113. This is a configuration diagram of a conventional screw surface inspection device of this type shown in Japanese Patent Application Laid-Open No. 60-253906. In the figure, 1 is a test object with a screw IA machined on the tube end, and 2 is a test object 1 rotated. The turning roller 3 is, for example, disclosed in Japanese Patent Application Laid-Open No. 58-1468.
43, the light is irradiated at a predetermined angle to the normal line (hereinafter referred to as normal line) passing through the irradiation point on the surface of the screw IA, and the axial direction of the screw IAO of the subject 1 is irradiated. A light projection system that overscans and scans the tube end; 4 is a light projection system 3;
5 is the reflected light of the irradiated light 4 reflected from the subject 1, and 6 is the reflected light of the irradiated light 4 that overscans the tube end and is scanned in the axial direction. Overscan irradiation light not reflected by specimen 1, 7
is a light receiving system that captures the reflected light 5. Since the irradiated light 4 and the reflected light 5 have equal angles with respect to the normal line, they are placed at an appropriate position to receive the light. 8 is a tube end detector that detects the tube end by receiving the overscan irradiation light 6; 9 is a light guide that guides the light captured by the tube end detector 8 to a photoelectric converter 10 (for example, a photomultiplier tube); 1;
1 is a position detector such as a touch roller that detects the surface height of the subject 1; 2 is a spring mechanism that pushes down the column 13 supporting the position detector 11 when the position detector 11 is free; 14 is a spring mechanism This is a detector such as a limit switch that is operated by a striker 15 attached to a column 13. These position detectors 11. Spring mechanism 12. Pillar 13. A detector 14 and a striker 15 constitute a subject detector 30. 16 is a light projection system 3. Light receiving system 7. Photoelectric converter 10° spring mechanism 12. Pillar 13. The inspection head 17 houses the detector 14, etc., and 17 is a lifting mechanism for the inspection head 16, which uses an electric motor, oil pressure, air pressure, etc. as a power source. A positioning device 40 that maintains a predetermined positional relationship between the light emitting system 3, the light receiving system 7, and the subject 1 using the detected device 30 and the lifting mechanism 17.
functions as Next, the operation will be explained. When the subject l is set in a predetermined position by a transport facility (not shown), the elevating mechanism 17
The inspection head 16 performs processing. When the position detector 11 hits the subject 1, the spring mechanism 12 is compressed, the striker 15 hits the detector 14, the subject 1 is detected, and the lifting device 17 is stopped. At this time, the light projection system 3. The positional relationship between the light receiving system 7 and the subject 1 is maintained at a predetermined value. Next, the turning roller 2 rotates, and light is emitted from the light projection system 3. Since the irradiation light 4 overscans and irradiates the tube end of the subject 1, it first enters the tube end detector 8, and when the overscan irradiation light 6 is blocked by the tube end, the tube end detector 8 enters the tube end detector 8. There will be no signal. From this point on, reflected light 5 is generated,
The light is captured by the light receiving system 7. FIG. 7 shows this situation on a time axis. That is, by using the edge where the tube end detector signal disappears as the synchronization signal for starting the detection area,
The timing at which the signal to be inspected from the object 1 outputted by the light receiver 7 is processed can be known, and the surface inspection can be easily performed. Note that since the subject 1 is being rotated by the turning roller 2, the entire circumference of the subject 1 can be inspected by repeating scanning with the irradiation light. However, since the object l moves in the axial direction by rotating, it is necessary to provide a margin for the tube end detector 8 in the axial direction, including the positioning accuracy of the transport equipment (this length is ). Furthermore, since the positioning device 40 operates using the operation of the position detector 11 as a trigger, it is possible to maintain a predetermined positional relationship even if the outer diameter of the subject I changes. FIG. 8 shows this situation. In Figure 8,
la is a test object with a different outer diameter from test object 1, 3a, 4a, 5
a, 6a, and 7a are the light projection system, irradiation light 1 reflected light, overscan irradiation light, and light receiving system when the number of objects to be examined is 13. The angle θ1 with respect to the normal of the irradiated light 4 and the angle e2 with respect to the normal of the reflected light 5 are equal, and similarly, the angle θ3 with respect to the normal of the irradiated light 4a and the angle θ4 with respect to the normal of the reflected light 5a are also equal. Furthermore, since the subjects 1 and 1a ride on the turning roller 2, their centers are on the normal line in FIG. Therefore, even if the outer diameter of the objects 1 and 1a changes, since the irradiated lights 4 and 4a and the reflected lights 5 and 5a are parallel, θ1
~θ4 are all equal. Next, the overscan irradiation light 6 enters the tube end detector 8.
Considering this, the overscan irradiation light 6 changes to point A, and the overscan irradiation light 6a changes to point B. If the distance between point A and point B is m, then the light receiving surface of tube end detector 8 is m
An area of X 1 is required. FIG. 9 shows the light receiving surface of this tube end detector 8.

[Problem to be solved by the invention]

Since the conventional screw surface inspection device is configured as described above, when the outer diameter of the object to be inspected changes, the positional relationship between the light emitting system and the tube end detector changes as shown in Fig. 8. The light-receiving surface of the tube end detector must be made wider in the direction of the arrow in Fig. 8, which increases the light-receiving area of the tube end detector. In some cases, it may be necessary to reset the tube end detector depending on the outer diameter of the test object. If a large-diameter photomultiplier tube (for example, a large-diameter photomultiplier tube, etc.) were used, the device would become larger and more expensive, but the problem still remains that the above-mentioned problem cannot be essentially solved. This invention was made to solve the above-mentioned problems, and provides a screw surface inspection device that can detect a tube end synchronization signal without being affected by the outside diameter of the object to be inspected, and that can reduce the size of the device. The purpose is to obtain.

[Means to solve the problem]

The surface inspection device for a screw according to the present invention includes an optical system having a directional light focusing function between a tube end and a tube end detector in a direction that allows overscan irradiation light in the direction of the outer diameter of the screw to be focused. This is how it is placed.

[For use]

The optical system in this invention that has directionality in its light focusing function allows light to be received by the tube end detector without affecting the scanning direction of the irradiated light (no change in the temporal relationship between the synchronization signal and the signal to be inspected). By focusing only the light in the surface width direction (m in Figure 9), the light focusing limit of the optical system (light focusing performance of the optical system) is narrowed, and the light receiving area of the tube end detector (photoelectric The light-receiving area of the converter can be made smaller.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. Note that the same or equivalent parts as in FIGS. 5 and 6 showing the prior art described above are indicated by the same reference numerals. Figure 1,
In Fig. 2, 21 focuses light in the direction of the arrow ■ pointing in the radial direction of the subject 1, but does not focus in the direction of the arrow ■ pointing in the longitudinal direction of the subject 1 (depending on the light incident state). Stored under fixed conditions) Optical diameter (e.g. cylindrical lens), 2
2 is a tube end detector whose light-receiving area is significantly smaller than that of the tube end detector 8 shown in FIG. 5; 23 is a light guide whose cross-sectional area is reduced compared to the light guide 9 shown in FIG. 5; and 24 is a light guide whose cross-sectional area is reduced compared to the light guide 9 shown in FIG. A photoelectric converter (for example, a semiconductor photoelectric converter such as a bin photodiode, which is small and inexpensive) has a reduced light-receiving area compared to the photoelectric converter 10 shown in FIG. This is a smaller inspection head. Next, the operation will be explained. When the subject 1 is set at a predetermined position, the inspection head 25 is lowered by the lifting mechanism 17, and when the subject detector 30 consisting of the position detector 11 to the striker 15 is activated, the lifting mechanism 17 is stopped and the next The turning roller 2 rotates and the light is emitted from the light projector 3, as in the conventional device. Overscan irradiation light 6
The light enters the optical system 21 which has a directional light focusing function, is focused in the direction of the arrow (■), and enters the tube end detector 22. On the other hand, since the light is not focused in the direction of the arrow ■ by the optical system 21, there is no change in the relationship between the irradiation light position and the time axis (Fig. 7) in the scanning direction, and at the tube end of the subject 1. When the overscan illumination light 6 is blocked, the signal of the tube end detector 22 disappears. Thereafter, the entire circumference surface inspection is easily performed using the tube end synchronization signal and the signal to be inspected, as in the conventional apparatus. Further, the length margin (length A) in the direction of the arrow (■) is also the same as that of the conventional device. Next, a case where the outer diameter of the subject changes will be explained using FIG. 3. Since the relationship among the light projecting system 3.3a, the light receiving systems 7, 7a, the irradiated light 4.4a, and the reflected lights 5,5a is the same as in the conventional apparatus, there is no change in the detection of the signal to be inspected. - On the other hand, regarding the relationship between the overscan irradiation lights 6 and 6a, the optical system 21 and the tube end detector 22 are perpendicular to the overscan irradiation light 6 (in the paper), and the focal length of the optical system 21 is maintained. The overscan irradiation light 6 is focused by the optical system 21 and collected at the tube end detector 22 (2). If you take a certain time, it theoretically becomes a point in terms of geometric optics, but
In reality, it has a certain width due to the condensing limit of the optical system 21 (this is assumed to be n). Next, even when the outer diameter of the object changes and the overscan irradiation lights 6 and 63 become the overscan irradiation lights 6 and 63, since the overscan irradiation lights 6 and 6a are parallel, the light is still focused on the focal position (■) of the optical system 21. Ru. In other words, the light is focused on ■ regardless of the outer diameter of the object. From the above, it follows that the light receiving surface of the tube end detector 22 only needs to be n×l. (n is extremely small compared to m). FIG. 4 shows the light receiving surface of the tube end detector 22. In the above embodiment, a cylindrical lens is used as an optical system having a directionality in the light condensing function, but it goes without saying that the light condensing function of a mirror may also be used. In the above embodiment, like the conventional device, the output of the tube end detector 22 is guided by the light guide 23 to the photoelectric converter 24 installed inside the inspection head 25, but the photoelectric converter 24 is extremely small. In other words, by installing a photoelectric converter 24 on the side of the tube end detector 22 and sending an electrical signal output from the photoelectric converter 24 to the inspection head 25 instead of the light guide 23, the light guide 23 can be replaced with an electric wire. At the same time, it is also possible to further downsize the entire device. Moreover, it goes without saying that the configuration according to the present invention can be widely applied to the inspection of the object 1 to be inspected whose outer diameter changes and whose surface to be inspected is closer to the end of the cylindrical body.

【Effect of the invention】

As described above, according to the present invention, an optical system having a directional light focusing function is arranged on the tube end and the tube of the tube end detector so as to be able to focus the overscan irradiation light in the direction of the outer diameter of the screw. With this configuration, the tube end synchronization signal for starting the inspection area can be obtained without being affected by the outer diameter of the subject, and the apparatus can be made smaller and cheaper.

[Brief explanation of the drawing]

1 and 2 are a front view and a right side view of a screw surface inspection device according to an embodiment of the present invention, FIG. 3 is an explanatory diagram of the operation of the device according to an embodiment of the present invention, and FIG. The light-receiving surface view of the tube end detector used in this invention, FIGS. 5 and 6 are a front view and a right side view of a conventional screw surface inspection device,
FIG. 7 is a time axis explanatory diagram of the tube end detector detection signal and the signal to be inspected, FIG. 8 is an explanatory diagram of the operation in the conventional device, and FIG. 9 is a view of the light receiving surface of the tube end detector in the conventional device. 1 is an object to be inspected, 2 is a turning roller, 3 is a light projecting system, 7 is a light receiving system, 11 to 15.17 are positioning devices, 21 is an optical system with directionality in the light focusing function, 22 is a tube end detector, 40 is a positioning device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant: Mitsubishi Electric Corporation - Procedural amendment (voluntary)

Claims (1)

[Claims] The tube end is irradiated with light at a predetermined angle to the normal passing through the irradiation point on the surface of the screw, and the tube end is threaded in the axial direction of the screw. a light emitting system that scans by overscanning; a light receiving system that captures the reflected light from the screw; a positioning device that maintains a predetermined positional relationship between the light emitting system, the light receiving system, and the subject; a tube end detector that detects that the light that is being overscanned has come to the tube end when the light is blocked by the tube end; In a screw surface inspection device, an optical system having a directionality for focusing light is installed between the tube end and the tube end detector to detect the outer diameter of the screw and generate a synchronization signal to start the inspection area. A screw surface inspection device characterized by being provided so that directional overscan irradiation light can be focused.