JPS586142B2 - Internal inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inner surface inspection device for detecting minute scratches on the inner surface of a cylindrical object.

Conventional methods for detecting and inspecting flaws or other defects on the inner surface of cylinders, etc. have been to use laser beams, fiberscopes, internal mirrors, magnetic flaw detection, air micrometers, etc. without making contact with the inspected object. There are several methods, but all of them are affected by cutting oil, dirt, chips, etc. attached to the object to be inspected.

The present invention employs a contact method with the object to be inspected, and by detecting a minute flow of air, flaw detection on the inner surface of the object to be inspected can be performed at low cost and without being affected by adhering cutting oil, dirt, chips, etc. It is something that must be done with great sensitivity.

In order to achieve the above object, in the present invention, in order to sufficiently seal the detection arbor that scans the cylindrical inner surface to be inspected, the annular sliding peripheral edge of the detection part against the inner surface to be inspected is replaced by a periphery with an acute angle in cross section. , and its material is a synthetic resin capable of elastic strain or a light metal,
The apparatus is equipped with a circumferential edge expanding device consisting of a conical inner surface and a conical outer circumferential surface that engages with the conical inner surface, and further defines an air pressurizing chamber by a sealing portion formed by the circumferential edge and the inner surface to be inspected.

The invention will now be explained with reference to the figures.

In FIG. 1, the shaft 1 is along the central axis and the passage 2
has.

The passage 2 has an inlet 3 at the bottom and outlets 4 and 13 at the top.

The outer periphery of the shaft 1 has a piston 5 on the lower side and a nut 6 on the upper end.

A cylinder 7 is fitted onto the shaft 1 so as to surround the piston 5.

The cylinder 7 has an inlet 8 which leads to a pressurized chamber 9 within the cylinder.

A tubular guide 10 is slidably fitted onto the shaft 1 above the cylinder 7 .

A detection unit 11 is also slidably fitted onto the shaft 1 above the guide 10.

Above the detection part 11, another tubular guide 12 is connected to the shaft 1.
It fits.

14 and 15 indicate O-rings for sealing. Both upper and lower guides 12.10 have conical tapers 12a and 10a on opposite sides, respectively.

Inner tapered portions 11a are provided at both upper and lower ends of the detection portion 11, respectively, to match the tapered portions 12a and 10a.

Each guide 10 and 12 has an annular groove 10b, 12b adjacent each tapered portion 10a, 12a.

There are holes 10c, 12c in the bottom of each annular groove 10b, 12b.

Note that this annular groove 10b. The inner diameter of each guide corresponding to 12b is slightly larger than the outer diameter of the shaft 1, and the annular gap 10d. 12d are formed respectively.

Both upper and lower outlets 4 and 13 of the shaft 1 are connected to this annular gap 1.
Openings are made at 2d and 10d, respectively.

A plate 16 is attached to the opening edge of the lower cylinder 7.

A fine adjustment screw 17 engages with the plate 16 .

The inner end of the screw 17 faces the piston 5 within the cylinder 7.

18 is a compression coil spring, and 19 is a locking nut.

The above-described portion is the detection arbor and is designated by the reference numeral B in the overall view of FIG.

The detection arbor B is supported on the main body A shown in the figure with a support 20 and a branch 21.

An air cylinder 22 is fixed to the branch 21, and the shaft 1 of the arbor B is connected to the top of the piston rod 23 via a joint 24.

The small diameter portion of the cylinder 7 of the arbor B freely passes through the guide 25 of the main body A.

The piston rod 23 is moved up and down quietly by the operation of the air cylinder 22, and the inner surface is inspected as described later.

Adjustment screw 26 for speed adjustment protruding below the air cylinder
By turning , the speed of the vertical movement of this piston rod 23 can be adjusted.

A microflow meter C placed on the upper right side of the main body is interposed between an air source (not shown) and the inlet 3, and connects the air flow circuit from the air source to the annular grooves 10c and 12c via the passage 2. If there is a fluctuation in the flow, this fluctuation is detected.

When using the inspection apparatus of the present invention to inspect the inner surface of cylinders, such as automobile brake cylinders, as shown in the upper part of FIG. Place it inside the cylinder, install it, and prepare.

Thereafter, pressurized air is first supplied to the inlet 8 of the cylinder 7.

The pressurizing chamber 9 in this cylinder is pressurized, and the cylinder 7 rises slightly, causing the guide 10 to rise slightly at the upper end.

Since the nut 6 at the uppermost end of the arbor B is fixed to the shaft 1, as the guide 10 rises, the uppermost detection part 1
1 and the other guide 12 above it are pressurized both from above and below.

Therefore, the tapered portions 12a of both the upper and lower guides 12,10,
10a and the upper and lower inner surface tapered portions 11a of the detecting portion 11 that engage therewith, the upper and lower edges of the detecting portion 11 made of an elastic plastic material or light metal are slightly expanded.

This expanding action is a main feature of the present invention, and in order to make this possible, the thickness of the detecting section 11 is set to an appropriate thickness at the upper and lower mouth edges.

Further, the outer periphery of the upper and lower edges of the detecting portion 11 is a peripheral edge portion 11b having an acute angle in cross section, as shown in the enlarged view of FIG.

This peripheral edge portion 11b completes the seal against the inner circumferential surface of the cylinder by expanding.

By appropriately restricting the expansion of the peripheral edge portions 11b at both ends of the detection portion 11 for the sealing described above, sufficient sealing is not achieved and the peripheral edge portions 11b can slide against the inner surface of the cylinder.

For that purpose, the adjustment screw 17 at the lower right in FIG. 1 is operated.

Due to the tension of the coil spring 18, the adjustment screw 1 is
The upper end of the cylinder 7 and the lower surface of the piston 5 are separated from each other as shown in the figure, while the upper surface of the piston 5 abuts against a shoulder 7a on the inner surface of the cylinder 7 to maintain the pressurizing chamber 9.

However, when the pressurizing chamber 9 is pressurized, the cylinder 7 rises as described above until the head of the screw 17 comes into contact with the lower surface of the piston 5, and its rise is stopped.

By manually turning the screw 17, the cylinder 7
The above increase in can be adjusted in various ways.

By this adjustment, it is possible to adjust the expansion of both the upper and lower peripheral edges 11b of the detection part 11, and to appropriately adjust the seal pressure contact with the inner surface to be inspected.

After setting the seal of the detection unit 11 as described above, pressurized air for detection is supplied from the inlet 3 below the shaft 1.

At the same time, the lower air cylinder 22 (FIG. 2) is operated to scan the entire upper arbor B along the inner surface to be inspected via its piston rod 23.

Pressurized air for detection is supplied to the passage 2 in the shaft 1 from the inlet 3, and is led to the annular groove 12b via the upper outlet 4 and the hole 12c of the guide 12.

Similarly, pressurized air for detection is introduced from the lower outlet 13 of the shaft 1 into the annular groove 10b of the lower guide 10.

After the inspection preparation is completed, the upper annular groove 12b in Fig. 1 is sealed on both upper and lower sides with the seal 15 and the peripheral edge 11b of the detection part 11 (Fig. 3), and the lower annular groove 10b is also sealed in the same way. If there is no flaw 30, which will be described later, on the inner circumferential surface of the object to be inspected, the air that has reached both annular grooves 12b and 10b cannot flow any further.

There is therefore no air flow passing through the passage 2.

If there is a flaw 30 caused by a blowhole or the like on the inner circumferential surface of the object to be inspected, as shown in FIG. Air leaks.

At the moment of this air leakage, a fine airflow occurs within the passage 2.

This air flow propagates sequentially back from the inlet 3 at the bottom of FIG. 1 to the air flow in an external upstream air flow circuit (not shown).

Therefore, the flaw 30 can be detected by continuing the inspection while looking at the microflow meter C provided externally upstream.

The inner surface inspection is performed as described above.

When the joint 24 comes into contact with the limit switch 31 shown near the center of FIG. 2, the supply of air into the air cylinder is stopped, the piston rod 23 stops descending, and the inspection is completed.

As described above, in the present invention, since the material of the detection part 11 is made of plastic or light metal, the degree of expansion of the peripheral edge part 11b can be adjusted as appropriate, and the diameter of the inner surface of the object to be inspected can be changed. Even when the detection unit 11 is inspected, a perfect seal can always be maintained between the peripheral edge 11b of the detection unit 11 and the inner surface of the object to be inspected.

Therefore, even if there is no flaw 30 on the inner surface of the object to be inspected, an inspection result indicating that there is a flaw will not be generated due to the incomplete seal.

- Also, since the cross section of the peripheral edge 11b of the detection part 11 is formed at an acute angle, even a small flaw 30 will be covered by the peripheral edge 11b of the detection part 11, and its discovery will not be overlooked.

By inspecting the inner surface of a cylinder using the apparatus according to the present invention, even a very small concave flaw (about Q.3 mm in diameter and about 0.1 mm in depth) formed on the inner surface of the cylinder can be detected.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the main parts of the internal surface inspection device of the present invention, Fig.
The figure is a partial longitudinal sectional view of the entire arrangement, and FIG. 3 is a partially enlarged longitudinal sectional view. A: Body, B: Detection arbor, C:
...Minute flowmeter, 1...Shaft, 5.
...Piston, 6...Nut, 7...
... Cylinder, 10, 12 ... Guide, 11
...Detection unit, 22...Air cylinder,
23...Piston rond, 24...Joint.

Claims (1)

[Claims] 1. A shaft with a circular cross section, a tubular detection section made of an elastic plastic or elastic light metal material that fits airtightly and slidably onto the shaft, an annular peripheral edge with an acute angle cross section formed around the outer rim of the end of the tubular detection section, It has a conical inner surface formed on the inner periphery of the mouth edge, a conical outer surface that matches and engages with the conical inner surface at the end, and is slidably fitted onto the shaft with the conical outer surface facing the conical inner surface. a guide for expanding the annular periphery; a fluid-pressure-operated pressing means comprising a cylinder and a piston that interlock with the guide on the opposite side of the conical outer surface; and a hydraulic pressure means formed on the guide adjacent to the conical outer surface a detection arbor comprising an annular groove and an annular seal provided on the outer periphery of the guide on the opposite side of the conical outer surface with respect to the annular groove; An internal surface inspection device characterized in that the air flow circuit is connected to an air source through a passage formed in the air passageway, and further a microflow meter is interposed between the passageway and the air source.