JPH03237343A - Inspection device for tapered surface in cylindrical body - Google Patents

Abstract

PURPOSE:To inspect at which position on the tapered surface of the cylinder body a defect is generated by lighting the cylinder body downward from one side of the cylinder body and reflecting its illumination light at right angles to the tapered surface. CONSTITUTION:A downward lighting device 4 lights the cylinder body 5 to be inspected from one opening and a reflecting member 6 which has a reflecting surface for reflecting the illumination light at right angles to the tapered surface is inserted from the other opening of the cylinder body 5. Consequently, the incident light from the downward lighting device is reflected by the tapered surface when the tapered surface has no defect and is specular, and then returned by the reflecting surface of the reflecting member 6 to the same position on the tapered surface to travel backward in the original incidence direction. If there is a defect in the tapered surface, on the other hand, the incident light is not reflected by the tapered surface, so the quantity of the reflected light decreases. The position of the defect in the tapered surface can be decided.

Description

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

The present invention relates to a tapered surface inspection device for a cylindrical object that detects defects occurring within the tapered surface of a cylindrical object having a tapered surface. Here, the cylindrical object includes, for example, a nozzle for ejecting fuel in an engine, and defects occurring on the tapered surface of the nozzle include defects due to machining marks, poor surface accuracy, unprocessed surfaces, and the like.

[Conventional technology]

In cylindrical objects with tapered surfaces, such as fuel injection nozzles in engines, defects may occur on the tapered surface during manufacture of the nozzle due to machining marks, poor surface accuracy, unfinished surfaces, etc. If a nozzle is installed inside the engine, the fuel cannot be sprayed out evenly, resulting in a decrease in engine combustion efficiency. Therefore, in order to detect defects that occur on the tapered surface inside a cylindrical object, there has been a method of visual inspection using a stereomicroscope by an inspector, but this visual inspection results in variations in inspection accuracy. Due to these inconveniences, it has been considered to automate this defect inspection. Defect inspection devices that automate visual inspection have been performed using image processing devices that use, for example, two-dimensional image input devices. This defect inspection device illuminates a cylindrical object with epi-illumination from a large diameter opening, reads the reflected light with a two-dimensional image input device, and inputs the image signal from the two-dimensional image input device into the image memory of an image processing device. After this image data is binarized into a normal part and a defective part, a defect inspection is performed by measuring the defective part within a designated window.

[Problem to be solved by the invention]

However, the defect inspection apparatus described above had the following disadvantages. The light incident from the large-diameter opening of the cylindrical object by the epi-illumination device is transmitted when the taper angle of the cylindrical object is 4, as shown in Figure 4 (1).
In the case of 5", the incident light a near the center of the cylindrical object and the incident light a far from the center are reflected twice on the tapered surface and return to the original direction of incidence. Therefore, the two-dimensional Although it is possible to detect defects by reading them with an image input device, it was not possible to determine which of the opposing tapered surfaces the defect was on.Also, as shown in Figure 4 (2), When is 30', the incident light a' is reflected at the first tapered surface and has an incident angle of 00 with respect to the opposing tapered surface, so that the reflected light a' returns in the same direction as the incident light a. Therefore, if there is a defect on the tapered surface, the reflected light a decreases, making it possible to detect the presence or absence of the defect. It was not possible to determine whether there was a defect. In addition, since the incident light beam is reflected once on the tapered surface and then reflected outside from the small diameter opening of the cylindrical object, even if the tapered surface is normal, the reflected light is reflected by a two-dimensional image input device installed above. There was an inconvenience that it could not be read.

[Means to solve the problem]

The present invention solves the above-mentioned problems and provides an in-cylindrical object tapered surface defect inspection device that inspects where a defect has occurred on the tapered surface of a cylindrical object, namely, one of the nozzles. an epi-illumination device that illuminates from the mouth; a reflective member that is inserted from the other mouth of the nozzle and has a reflective surface that irradiates the epi-illumination light in a direction perpendicular to the tapered surface of the cylindrical object; a two-dimensional image input device that inputs an image of the tapered surface obtained through a reflective surface of a member; and a tapered surface inside the cylindrical object based on the image data input from the two-dimensional image input device. An apparatus for inspecting a tapered surface in a cylindrical object is characterized by comprising an image processing device that binarizes the tapered surface and detects defects included in the tapered surface.

[Effect]

The apparatus for inspecting defects on a tapered surface in a cylindrical object according to the present invention emits epi-illumination from one opening of the cylindrical object, and has a reflective surface that reflects the illumination light in a direction perpendicular to the tapered surface, as in the conventional apparatus. The reflective member is inserted from the other opening of the cylindrical object. As a result, if the tapered surface has no defects and is a mirror surface, the incident light from the epi-illumination will be reflected by the tapered surface, and then returned to the same position on the tapered surface by the reflective surface of the reflective member, returning to the original direction of the incident light. That will happen. However, if a defect occurs on the tapered surface, the amount of reflected light decreases because the incident light is not reflected as described above on the tapered surface. Therefore, the position of the defect on the tapered surface can be determined. Hereinafter, it will be explained with reference to the drawings that a defect occurring on a tapered surface within a cylindrical object can be detected by a reflective member. FIG. 2(1) shows a case where the angle θ of the tapered surface of the cylindrical object is 45°. As shown in the figure, the reflecting member 6 forms a conical reflecting surface, and the reflecting member 6 is inserted from the large diameter opening of the cylindrical object 5. Incident light a due to epi-illumination,
Since b is reflected twice on the same tapered surface, the reflected light al
bl returns in the same direction as the incident light a1b. Therefore, the location of defects occurring on the tapered surface can be determined. Note that the angle α of the conical portion forming the reflective surface is expressed by the following equation. α depth 180'-20

【Example】

FIG. 1 is a diagram showing an example of a device configuration of the present invention. The test object 5 is a cylindrical object such as a nozzle as shown in FIG. 2 (1), and is, for example, a nozzle with a tapered surface having an angle of 45°, a small diameter opening of 1 mmφ, and a large diameter opening of 2 mmφ. Further, in the same figure, an inspection object 5 is set on a reflecting member 6. The reflecting member 6 has a conical reflecting surface, and its angle α
is 90°. In addition, the surface is mirror polished and has no irregularities or scratches. The angle α of the conical portion of this reflecting member is appropriately designed according to the taper angle θ of the inspection object 5.
The angle α becomes α=180−2θ. Furthermore, the reflective surface of the reflective member 6 is not limited to a conical shape, but may be any surface that can irradiate light in a direction perpendicular to the tapered surface. For example, as shown in FIG. 2 (2), it may be shaped like a forest, and the angle α in this case is α=270@+θ. Further, as shown in FIG. 3(3), the reflecting member 6 may be moved back and forth in the direction of the arrow so that the entire tapered surface can be inspected. The epi-illumination device i14 illuminates the inspection object 5 with light emitted from a light source 4a from one side using a half mirror 4b, and sends the reflected light to the CCD camera 1 via the half mirror 4b. The CCD unit 1 receives reflected light from the inspection object 5 and sends image data regarding the tapered surface of the inspection object 5 to the image processing device 2 . The image processing device 2 inputs the image data from the CCD camera 1 into the image memory, specifies a circular window based on the size of the small diameter aperture and the large diameter aperture of the inspection object 5 for the data in the memory, and Extract only data related to tapered surfaces. Then, the image processing device 2 detects a defect based on the extracted data regarding the tapered surface by observing a change in the shading level if there is a defect, and measures the area, position, etc. of the detected defect. When the image processing device 2 detects a defect, the monitor TV 3 displays an indication that there is a defect, for example, rNGJ. Next, the functions of the apparatus for inspecting a tapered surface inside a cylindrical object according to the present invention will be explained. FIG. 3 is a flowchart showing the image processing procedure of the present invention. Defect inspection can be performed by repeating steps 1 to 2 below. ■ Start the inspection by inputting the start signal. ■ Input a binary image from CCD camera 1. ■ Defects (white areas) within the specified circular window range.
Measure the area of ■ If a defect is detected, it is determined as an error and the monitor T
V is indicated as rNGJ. ■ If no defects are detected, rOKJ will be displayed on the monitor TV.
is displayed. ■ Jump to above. [Effects of the Invention] As described in detail above, the apparatus for inspecting a tapered surface inside a cylindrical object according to the present invention emits epi-illumination from one side of the cylindrical object, inserts a reflective member from the other opening, and allows this reflective member to illuminate. Since light is reflected in a direction perpendicular to the tapered surface, if there is no defect on the tapered surface, the reflected light will return to the same position as the incident light, and if there is a defect, the reflected light will decrease, so it is possible to accurately locate the defect. can be determined. Therefore, it is highly effective when used as a device for inspecting the tapered surface of a cylindrical object.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the device configuration of the present invention, and FIG. 2 is a cross-sectional view showing the state of light reflection on the tapered surface of a cylindrical object into which a reflecting member is inserted, in order to explain the present invention in detail. 3 is a flowchart showing the image processing procedure of the present invention, and FIG. 4 is a sectional view showing the state of reflected light on a cylindrical object by a conventional inspection device. 1... CCD camera, 2... Image processing device, 3... Monitor TV. 4... Epi-illumination device, 6 - Inspection object, - Reflective member

Claims (1)

[Scope of Claims] An apparatus for inspecting a tapered surface in a cylindrical object for inspecting defects occurring on the tapered surface of a cylindrical object having a tapered surface, comprising: an epi-illumination device that illuminates from one mouth of a nozzle; A reflective member is inserted through the other opening of the nozzle and has a reflective surface that irradiates the light of the epi-illumination in a direction perpendicular to the tapered surface of the cylindrical object, and the reflected light is obtained through the reflective surface of the reflective member. A two-dimensional image input device inputs an image of the tapered surface, and the tapered surface inside the cylindrical object is extracted and binarized from the image data input from the two-dimensional image input device, and the tapered surface is An apparatus for inspecting a tapered surface inside a cylindrical object, comprising an image processing apparatus for detecting defects contained therein.