JP2743984B2 - Inspection method for honeycomb structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method for inspecting internal defects of a bent honeycomb structure.

[0002]

2. Description of the Related Art Conventionally, as a device for inspecting internal defects of a honeycomb structure having a large number of through holes due to clogging, breakage or deformation of partition walls, Japanese Utility Model Application Laid-Open No. 56-167249, The ones disclosed in JP-B-62-53767 and JP-B-63-53495 are known. Each inspection device irradiates a light beam from one end face of the straight honeycomb structure, and directly or indirectly looks at a projection view projected on a screen by a light beam passing through the honeycomb structure, using a photographing machine, etc. Inspect for internal defects.

[0003]

However, when the bent honeycomb structure is inspected by the above-described inspection apparatus, since the through-hole is bent, the irradiation light is absorbed by the partition wall of the through-hole and there is not enough light in the projected view. In addition, there is a problem that it is difficult to visually confirm the internal defect of the bent honeycomb structure.

The present invention has been made to solve the above problems, and has as its object to provide an inspection method capable of visually inspecting internal defects of a bent honeycomb structure with high accuracy.

[0005]

A method for inspecting a curved honeycomb structure according to the present invention for solving the above-mentioned problems is a method for inspecting internal defects of a curved honeycomb structure having a large number of through holes. R is the center radius of curvature of the honeycomb structure, D is the inscribed diameter of the through-hole of the curved honeycomb structure, θ is the cutting angle of both end faces of the curved honeycomb structure, β is the straight-forward angle of the irradiation light beam, and the curvature coefficient of the curved honeycomb structure. Let K be the illuminance of the entrance surface of the curved honeycomb structure, and let Lx be the rectilinear angle β of the irradiation light beam, β = 2 cos ⁻¹ {(R−D / 2) / R} The central curvature K of the curved honeycomb structure. , K = 100θ / βR, the illuminance Lx of the entrance surface of the curved honeycomb structure
Is inspected in the range of Lx ≧ 20000K-10000.

[0006]

According to the method for inspecting a honeycomb structure of the present invention, by irradiating a light beam having an appropriate illuminance from one end face of the curved honeycomb structure, internal defects of the curved honeycomb structure can be visually observed.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a curved honeycomb structure inspection apparatus to which a honeycomb structure inspection method according to the present invention is applied. A curved honeycomb structure inspection apparatus 10 shown in FIG. 1 includes a light source 11 for irradiating a curved honeycomb structure 20 with light, a reflecting mirror 12 for reflecting the light of the light source 11 in a forward direction of the light source 11, and a radial irradiation from the light source 11. Lens 13 that converts the formed light beam into a parallel light beam, a glass plate 14 serving as a partition wall between the curved honeycomb structure 20 and the convex lens 13, and a bottomless cylindrical tube that fixes the reflecting mirror 12, the convex lens 13, and the glass plate 14 to the inner wall. The body 15 includes a bottomless cylindrical fixing member 16 for fitting and fixing the bent honeycomb structure 20.

As the light source 11, a light source having a large light flux such as a halogen lamp is used. Inner wall 12 of reflector 12
a is a light beam emitted from the light source 1
The light is reflected in the same direction as the radial light beam directly emitted from the light source 1. The light beam of the light source 11 collimated by the convex lens 13 is bent through the glass plate 14 and applied to the entrance end face 20 a of the honeycomb structure 20. As shown in FIG. 3, the light beam travels while reflecting through the through hole 21 of the curved honeycomb structure 20 at the partition wall 20c.

The other end surface 2 of the curved honeycomb structure shown in FIG.
At 0b, the range of the eye position diameter of about several tens of millimeters looks bright, and the outer portion thereof is dark as indicated by the oblique lines. By moving the position of the eye, the other end surface 20b
Inspect the whole. A dark portion 41 shown in FIG. 2 indicates that the through hole 21 is clogged or the partition wall 20c is damaged. In order to be able to visually inspect the other end face 20b and inspect the internal defects of the curved honeycomb structure 20 in this way, even if light rays are absorbed by the partition walls 20c of the curved honeycomb structure 20, the curved honeycomb structure 20 is still in use. A light source having a luminous flux capable of visually observing the internal defect is required.

Next, an experiment was conducted on the relationship between the shape or size of the bent honeycomb structure and the illuminance at the entrance end face of the bent honeycomb structure in which internal defects of the bent honeycomb structure could be visually observed. Bent honeycomb structure 20 used in experiment
Indicates a cell structure: 6 mil / 400 cpi ² , and a partition wall thickness: 0.
17 mm, number of cells per unit area: 62,000 cells /
m ² , major axis of cross section: 95 mm, minor axis of cross section: 70 m
m.

The variables that define the shape of the curved honeycomb structure will be described below. Both ends cutting angle θ shown in FIG.
Represents the angle formed by the inlet end face 20a and the other end face 20b of the curved honeycomb structure 20, and the center curvature radius R represents the radius of curvature of the center line of the curved honeycomb structure 20 indicated by a dashed line. The straight traveling angle β shown in FIG.
The light rays entering at right angles from the entrance end face 20a of the
3 represents an angle formed by a straight line connecting two adjacent points 20d reflected by c and the center of curvature 51 of the curved honeycomb structure 20 shown in FIG. The through-hole inscribed diameter D shown in FIG. 5 represents the inside diameter of the through-hole 21 of the bent honeycomb structure 20. The rectilinear angle β can be defined as the following equation by the center radius of curvature R and the diameter D of the inscribed through-hole.

Β = 2 cos ⁻¹ {(R−D / 2) / R} Further, the cutting angle θ at both ends, the radius of curvature of the center R, and the rectilinear angle β
Defines the curvature coefficient K as follows. K = 100θ / βR Here, the curvature coefficient K defined by the both-end cutting angle θ, the center curvature radius R, and the rectilinear angle β, and the presence / absence of an internal defect of the bent honeycomb structure when the curvature coefficient K is changed are described. Table 1 shows the results of experiments conducted on the relationship with the illuminance Lx of the entrance end face of the curved honeycomb structure that can be visually observed. In Table 1, when it is possible to detect the presence or absence of the internal defect of the bent honeycomb structure, ○ is shown, and when impossible, X is shown.

[0013]

[Table 1]

FIG. 6 is a characteristic diagram in which the horizontal axis represents the curvature coefficient K in Table 1 and the vertical axis represents the illuminance Lx of the entrance end face of the curved honeycomb structure. The straight line 100 represents a boundary line indicating whether the presence or absence of an internal defect of the bent honeycomb structure is visible or invisible, and is defined by the following equation (1). Lx = 20,000K-10000 (1) From FIG. 6 and Equation (1), the illuminance Lx at the entrance end face of the curved honeycomb structure is in the range of the following equation (2): Lx ≧ 20000K-10000 (2) If there is, it is possible to visually determine the presence or absence of an internal defect in the bent honeycomb structure, and if a light source having an illuminance satisfying Expression (2) is prepared, it is possible to inspect the internal defect in the bent honeycomb structure. I understand.

[0015]

According to the method for inspecting a honeycomb structure of the present invention, by setting the illuminance of a light source in a specific range according to a curvature coefficient, an internal defect of a bent honeycomb structure can be easily inspected. is there.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a bent honeycomb structure inspection apparatus to which the honeycomb structure inspection method of the present invention is applied.

FIG. 2 is a view in the direction of arrow II shown in FIG.

FIG. 3 is a schematic longitudinal sectional view of a curved honeycomb structure to be inspected.

FIG. 4 is an explanatory diagram showing a path of a light beam.

FIG. 5 is a schematic partial enlarged cross-sectional view of a curved honeycomb structure to be inspected.

FIG. 6 is a characteristic diagram illustrating a relationship between a curvature coefficient of a curved honeycomb structure and an illuminance at an entrance end face of the curved honeycomb structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inspection apparatus of curved honeycomb structure 11 Light source 12 Reflector 13 Convex lens 20 Curved honeycomb structure

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/84-21/90

Claims (1)

(57) [Claims] 1. A method for inspecting an internal defect of a curved honeycomb structure having a large number of through holes, wherein a radius of curvature of a center of the curved honeycomb structure is R, a diameter of an inscribed hole of the curved honeycomb structure is D, Assuming that the angle at which both ends of the curved honeycomb structure are cut is θ, the angle at which the irradiated light beam travels straight is β, the curvature coefficient of the curved honeycomb structure is K, and the illuminance at the entrance surface of the curved honeycomb structure is Lx, the angle at which the irradiated light beam travels is β Where β = 2 cos ⁻¹ {(R−D / 2) / R} where K = 100θ / βR represents the central curvature K of the curved honeycomb structure, and the illuminance Lx of the entrance surface of the curved honeycomb structure
Is inspected in the range of Lx ≧ 20000K-10000.