JP2003294710A - Inspection device for inner surface of work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection device for the inner surface of a work, which automatically detect in-line a blowhole and a scratch of a bore of the work, or a hole of a covering layer. <P>SOLUTION: Rotators 3 and 4 which rotate at a fine interval with respect to the inner surface of a bore 21 of a work 20 is provided at a lower and of a rotating shaft 2. A magnetic probe 5 and an adjacent sensor 6 are provided on outer peripheral surfaces of these rotators 3 and 4. The rotating shaft 2 is rotated by a drive motor 7 used as a driving means to detect the rotation angle by a rotary encoder 8, and the rotating shaft 2 is moved to a shaft center direction by a vertical moving means 10 used as a moving means to observe, using a monitor 12 of a personal computer 11, the change in output power obtained at the magnetic probe 5. Based on the change in output power, the inspection is made for a blowhole and a scratch on the inner surface of the bore 21 of the work 20 or a hole of a covering layer 33 by flame spray coating of an inner surface of a bore 31 of a work 30. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for inspecting the inner surface of a work, for example, a cavity or scratch existing on the inner surface of the work such as an automobile engine cylinder block formed by casting, or a coating formed by thermal spraying on the inner surface of the bore. The present invention relates to a device for inspecting an inner surface of a work suitable for in-line inspection of holes in layers.

[0002]

2. Description of the Related Art The engine cylinder block of an automobile is
There are a method of manufacturing the whole by casting iron, a method of manufacturing most of it by casting aluminum, and a method of mounting an iron liner on the inner surface of the bore. The former method in which the whole is manufactured by casting iron has a problem that cavities due to insufficient filling during casting and scratches during mold removal are likely to occur. Also,
The method of producing the majority of the latter by casting aluminum and mounting the iron liner on the inner surface of the bore has the same problems as described above, and not only is it troublesome to mount the liner on the aluminum casting part, but also aluminum casting There is a problem that a high precision dimensional tolerance is required between the inner diameter of the component and the outer dimension of the liner, and the liner is made of iron and becomes heavy.

Therefore, a method is conceivable in which the engine cylinder block is cast from aluminum and the inner surface of the bore is sprayed with iron to form a coating layer. This method sprays iron on the inner surface of the bore of an engine cylinder block manufactured by casting aluminum to form a coating layer, so that it is necessary to manufacture another object such as a conventional liner, or to use this liner for the bore of the engine cylinder block. There is an advantage that productivity can be remarkably improved because there is no complicated step of mounting on the inner surface and high precision dimensional tolerance between the engine cylinder block inner diameter dimension and the liner outer diameter dimension is not required.

[0004]

However, since it is difficult to take measures against the occurrence of cavities and scratches in the engine cylinder block formed by casting, it is necessary to inspect the cavities and scratches before forming the coating layer. However, since oil or dirt adhered to the inner surface of the bore may cause holes to be formed in the coating layer, after forming the coating layer on the inner surface of the bore, inspect the coating layer for holes. Will be required.

Inspection of cavities and scratches on the inner surface of the bore of this cast product,
Alternatively, as a method for inspecting the holes in the coating layer, for example, Japanese Patent Laid-Open No.
As described in Japanese Patent No. 18426, the inner surface of the bore is circumferentially scanned by a rotating mirror to form an image on a light receiving portion (CCD element or the like), and this image is developed into a linear image and displayed. As described in JP-A-6-241760, a circular band-shaped image is formed on a CCD element of a television camera through a conical mirror, and a circular capturing line is set on the image. There is a method in which pixels are taken out in a line and developed into a linear image for display.

Further, as described in Japanese Patent Application Laid-Open No. 11-23477, the entire inner surface of the bore is scanned and photographed by a line sensor in which image pickup elements are linearly arranged. There is a method in which a signal is captured and developed into a plane image, and the plane image is displayed on the display means.

However, in the apparatus for inspecting the inner surface of the bore by the optical method as described above, if oil or dirt adheres to the inner surface of the bore or the surface of the coating layer, it is erroneously detected as a porosity, a flaw, or a hole. However, the presence or absence of cavities, scratches, or holes could not be detected with high reliability. Therefore, such an optical inspection device could not be adopted in-line.

Therefore, although a method using X-rays is also conceivable, although this X-ray inspection apparatus is capable of automatic inspection, X-rays can be adopted inline from the viewpoint of the operator's health and safety. There wasn't.

There is also an apparatus that utilizes ultrasonic waves, but this ultrasonic inspection apparatus requires submersion of the engine cylinder block and equipment for using water. Since it is necessary to lay a water supply pipe and a drain pipe, the equipment becomes complicated, and the coating layer formed by spraying iron is oxidized by water, so that it cannot be used inline.

Therefore, at present, the operator is forced to inspect with the naked eye, but such an inspection method requires a long time for the inspection work and is inefficient. There is a problem in that the visual acuity of the worker is deteriorated due to eye strain and the reliability of the test is deteriorated when the work is continuously performed for a long time.

In view of the above, the present invention is directed to the inner surface of a bore of a work such as an engine cylinder block made of iron casting or aluminum casting described above, or a coating layer for a work in which a coating layer is formed by spraying iron on the inner surface of the bore. To provide an inspection device for the inner surface of a work that can inspect the work for the presence or absence of cavities or scratches, or the presence or absence of holes in the coating layer and their sizes automatically and with high reliability. With the goal.

[0012]

According to a first aspect of the present invention, there is provided a device for inspecting an inner surface of a work, wherein a rotating body which rotates in proximity to an inner surface of the bore of the work and a peripheral surface of the rotating body. It is characterized by comprising a magnetic probe provided, a rotating means for rotating the rotating body, and a moving means for moving the rotating body in the axial direction in the work.

According to such an apparatus for inspecting the inner surface of the work, since the magnetic probe is provided on the inner surface of the bore and the rotating body which rotates in proximity to the coating layer formed on the inner surface of the bore, the magnetic probe is provided on the rotating body. The output voltage obtained by the magnetic probe based on the eddy current generated in the inner surface of the bore of the workpiece and the coating layer by rotating the magnetic probe near the inner surface of the bore and the coating layer formed on the inner surface of the bore. It is possible to detect the presence or size of the porosity or scratches on the inner surface of the bore of the workpiece, or the presence or absence of holes in the coating layer.

That is, if there are no cavities or scratches on the inner surface of the bore of the work, or if there is no hole in the coating layer, the output obtained by the magnetic probe does not change due to the rotation of the rotating body, but if the inner surface of the bore of the work does not change. If there are cavities, scratches, or holes in the coating layer, the eddy current flow changes at the holes. By monitoring the output voltage change of the magnetic probe based on the change of the eddy current flow, it is possible to detect the presence or absence of a porosity or a scratch on the inner surface of the bore, or the size of the hole in the coating layer.

According to such a method, as compared with the conventional optical method using a camera, since it is an electromagnetic flaw detection method using an eddy current, a false alarm is caused due to the adhesion of oil or dirt. There is no. In addition, there are no safety and health problems for workers as compared with the X-ray inspection apparatus. Furthermore, since it is not necessary to submerge the work as compared with an inspection device that uses ultrasonic waves, not only is the equipment simplified, but there is no problem of oxidation of the coating layer due to the thermal spraying of iron. Therefore, it becomes possible to in-line inspect for cavities and scratches on the inner surface of the bore of the cast product, or holes in the coating layer due to thermal spraying, thus significantly improving productivity.

According to a second aspect of the present invention, there is provided a device for inspecting the inner surface of a work, characterized in that a proximity sensor is provided on the peripheral surface of the rotating body.

According to the above-mentioned inspection device for the inner surface of the work, the inclination of the work or the rotating body is corrected by the proximity sensor,
Since the distance between the proximity sensor and the inner surface of the bore of the work or the coating layer can be made constant, it is possible to mistakenly report the output change of the proximity sensor due to the inclination as a porosity, a scratch, or a hole in the coating layer. It can be prevented. For example, if one or both of the workpiece and the rotating body are tilted, the rotation of the rotating body changes the distance between the magnetic probe and the inner surface of the bore or its coating layer, and the output voltage of the magnetic probe is changed. Change, the output voltage change is
Alternatively, it may be falsely reported as a hole in the coating layer, but such false reporting can be prevented by making the distance dimension between the proximity sensor and the inner surface of the bore of the work or the coating layer constant.

In the inspection device for the inner surface of the work according to the present invention, the distance between the inner surface of the bore of the work and the magnetic probe is
It is desirable to set it within the range of 0.5 mm to 0.6 mm.

Here, if the distance between the inner surface of the bore of the work and the magnetic probe is less than 0.5 mm, the output voltage of the magnetic probe becomes too large and saturated, and the correct porosity, flaws, and hole size. Cannot be understood. When the distance between the inner surface of the bore of the work and the magnetic probe exceeds 0.6 mm,
The output voltage of the magnetic probe becomes too small, and it becomes difficult to determine the change in the output voltage. Therefore, by setting the distance between the inner surface of the bore of the work and the magnetic probe within the range of 0.5 mm to 0.6 mm, it is possible to easily form the cavities and scratches of the work, or the holes and the size of the coating layer, and It can be reliably detected.

In the inspection device for the inner surface of the work according to claim 3 of the present invention, the driving means and the moving means are XY.
It is characterized by being attached to a table.

According to the above-mentioned inspection device for the inner surface of the work, X
-Y by moving the table in the horizontal plane, X
Since the rotation axis of the rotating body mounted on the Y table can be aligned with the central axis of the bore of the work, the distance between the inner surface of the bore of the work and the outer peripheral surface of the rotating body can be made constant,
It is possible to detect with high accuracy the presence or size of a porosity or a flaw in a work, or a hole in a coating layer.

The inspection device for the inner surface of the work according to the present invention preferably has a personal computer to which the output voltage of the magnetic probe is applied.

According to the above-described inspection device for the inner surface of the work, the output voltage waveform displayed on the personal computer monitor to which the output voltage of the magnetic probe is applied is analyzed to determine whether there are cavities or scratches in the work, or whether there are holes in the coating layer. The size can be detected, and the quality of the work or the coating layer can be determined. Further, for example, when the rotation angle of the rotating body is taken as the horizontal axis and the time is taken as the vertical axis, and the relationship of the rotation angle-time is displayed in a two-dimensional coordinate diagram, at what position on the inner surface of the bore or the coating layer, and how much size. At a glance, you can see if there are cavities, scratches, or holes.

In the inspection device for the inner surface of the work according to claim 4 of the present invention, the moving means P is a moving pitch per one rotation of the rotating body, and a porosity, a flaw, or an outside of the hole to be detected. When the diameter dimension is A, P ≦ A-0.05 mm
It is characterized by being set in the relationship of.

According to the above-described inspection apparatus for the inner surface of the work, for example, if the outer diameter of the porosity, flaw, or hole to be detected is A, and A = 0.3 mm, then per revolution of the rotating body. The moving pitch is set to P ≦ 0.25 mm. Then, due to the rotating motion of the rotating body, 0.3 m existing on either the inner surface of the bore of the work or the coating layer.
Even if the porosity, scratches, or holes of m or more are to be scanned by the magnetic probe, it is possible to reliably detect them.

The apparatus for inspecting the inner surface of the work according to the present invention is suitable when the work is an engine cylinder block made of aluminum casting.

According to the above-mentioned inspection device for the inner surface of the work, it is possible to automatically detect the presence and size of the cavities and scratches existing on the inner surface of the bore of the engine cylinder block formed by aluminum casting, and perform the in-line inspection. Will be possible.

The apparatus for inspecting the inner surface of a work according to the present invention is also suitable for the case where a coating layer formed by thermal spraying of iron is formed on the inner surface of the bore of the work.

According to the above-mentioned inspection device for the inner surface of the work, it is possible to automatically detect the presence or absence and the size of the hole in the coating layer formed by the thermal spraying of the iron formed on the inner surface of the bore of the work. Will be possible

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION An inspection apparatus for an inner surface of a work according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the inspection device for the inner surface of the work, and FIG.
2A is a vertical cross-sectional view of an example of a work to be inspected, FIG.
(B) is a longitudinal sectional view of an example of a different work.

The work 20 shown in FIG. 2A has a cylindrical bore 22 in an engine cylinder block 21 made by casting aluminum. The work 30 shown in FIG. 2B is
Engine cylinder block 31 made of aluminum casting
Has a cylindrical bore 32, and a coating layer 33 formed by thermal spraying of iron is formed on the inner surface of the cylindrical bore 32.

The inspection device 1 for the inner surface of a work shown in FIG. 1 has disk-shaped rotating bodies 3 and 4 at the lower end of a rotating shaft 2, and magnetic probes are provided on the outer peripheral surfaces of these rotating bodies 3 and 4, respectively. 5
And a proximity sensor 6. The magnetic probe 5 is shown in FIG.
The inner surface of the bore 22 of the work 20 in FIG.
It is sufficient that an output can be obtained in accordance with the distance dimension with the coating layer 33 formed on the inner surface of the bore 32 of the work 30 in (B). The proximity sensor 6 detects the distance dimension between the inner surface of the bore 22 or the coating layer 33, and is composed of, for example, a magnetic sensor, a displacement sensor, an eddy current displacement sensor, a contact displacement sensor, and the like, Three pieces are provided at equal intervals in the direction, for example, every 120 °.

The rotary shaft 2 is rotationally driven by a drive motor 7 which is a drive means, and its rotational angle is detected by a rotary encoder 8. The drive motor 7 and the rotary encoder 8 include an XY table 9
It is mounted in a hanging form. This XY table 9
Is, for example, the X-direction slide member 9 below the fixing member 9a.
b and the Y-direction slide member 9c are superposed on each other. The fixing member 9a of the XY table 9 is supported by a vertically moving means 10 which is vertically movable by a moving means (not shown), and is configured to be vertically movable.

The magnetic probe 5 and the proximity sensor 6 are connected to the monitor 12 of the personal computer 11.
Therefore, it is possible to analyze the voltage waveform transferred to the monitor 12 on the basis of the output voltage of the magnetic probe 5 and determine the quality from the analysis result. With the above-described configuration, cavities and scratches on the inner surfaces of the bores 22 and 32 of the engine cylinder blocks 21 and 31, which are the works 20 and 30,
Alternatively, it is possible to inspect the presence or the size of the hole in the coating layer 33 formed on the inner surface of the bore 32.

For example, if the standard value of the outer diameter dimension A of the hole or flaw to be detected or the hole is 0.3 mm or more,
From the above relational expression of P ≦ A−0.05 mm, the spiral vertical movement dimension P for one pitch by one rotation of the rotating body 3 is
It is set to 0.25 mm. Here, if the rotation speed N of the drive motor 7 is N = 2,400 rpm (= 40 rps), the moving speed S in the axial direction by the vertical movement means 10 is
S = 0.25 [mm / rotation] × 40 [rps] = 10 m
m / s. Therefore, the bore 2 of the work 20, 30
When the length dimension L of 1 and 22 is 100 mm, the inspection of one bore is completed in 10 seconds. Of course, the required inspection time can be shortened by increasing the rotation speed N of the drive motor 7 or increasing the speed increasing ratio by providing the rotation speed transmission means.

FIGS. 3A to 3D show the work 20,
Φ30 mm × depth of 0.
When an artificial porosity having a size of 3 mm is formed and the distance between the magnetic probe 5 and the inner surface of the bore 21 of the work 20 is changed from 0.4 mm to 0.7 mm in 0.1 mm steps,
The output voltage waveform diagram obtained by the magnetic probe 5 by substantially one rotation of the rotating body 3 is shown. Note that FIGS. 3A to 3D
, The portion enclosed by the ellipse A ′ of the output voltage A is the detection signal of the artificial porosity, and the rectangular wave P below the output voltage A is
1 and P2 are rotation pulse signals.

That is, FIG. 3A shows the case where the distance between the magnetic probe 5 and the inner surface of the bore 21 of the work 20 is 0.4 mm, and the amplitude of the output voltage is the upper limit threshold value U of OK / NG.
It is saturated with respect to the upper saturation voltage value USL and the lower saturation voltage value LSL, which greatly exceed CL and the lower limit threshold value LCL and are saturated even when a waveform of more than this value is output. 3 (B) and 3 (C) show the case where the interval dimension is 0.5 mm and 0.6 mm, respectively, and the amplitude of the output voltage exceeds the upper and lower limit thresholds UCL and LCL of OK / NG. It does not reach the upper saturation voltage value USL and the lower saturation voltage value LSL, and has an appropriate size. FIG. 3D shows the case where the interval dimension is 0.7 mm, the amplitude of the output voltage is too small, and it is almost equal to the upper and lower limit threshold values UCL and LCL of OK / NG, so that it is difficult to determine OK / NG. is there. From the above results, the distance between the magnetic probe 5 and the inner surface of the bore 21 of the work 20 is 0.5 mm to
A range of 0.6 mm is suitable.

In FIG. 4A, with respect to the inner surface of the bore 21 of the work 20 in FIG. 2A, the rotary encoder 8 sets the rotation angle θ of the rotary shaft 2 on the horizontal axis, and the position of the magnetic probe 5 is determined from the elapsed inspection time. Rotation angle θ shown by bore length on the vertical axis
-A two-dimensional coordinate diagram of the bore length. That is, the change in the voltage waveform obtained by the magnetic probe 5 is detected by obtaining two-dimensional coordinate data in which the horizontal axis is the rotation angle θ (°) and the vertical axis is the length (mm) of the bore 2.
From the change position coordinate a of the output voltage waveform 5
It is possible to detect the position and size of the porosity and scratches on the surface of the bore 22.

FIG. 4 (B) shows the work 3 shown in FIG. 2 (B).
5 is a two-dimensional coordinate diagram similar to FIG. 4A in the case where a part of the coating layer 33 is artificially peeled to form a hole for 0. Also in this FIG. 4B, the position and size of the hole of the coating layer 33 formed on the inner surface of the bore 32 of the work 30 are detected from the detected change position coordinate b of the output voltage waveform of the magnetic probe 5. be able to

In the above embodiment, only a specific embodiment has been described, but it goes without saying that various modifications can be made without departing from the spirit of the present invention. For example,
In the above embodiment, the case where one magnetic probe 5 is provided on the outer peripheral surfaces of the rotating bodies 3 and 4 has been described, but a plurality of magnetic probes 5 may be provided at equal intervals in the circumferential direction. With this configuration, for example, when n magnetic probes 5 are provided, the inner surfaces 1 of the bores 21, 31 of the workpieces 20, 30 are rotated by 1 / n of the rotating bodies 3, 4.
The rotation (360 °) can be inspected, and the time required for the inspection can be shortened accordingly.

Further, the work 2 composed of the engine cylinder block 21 having the bore 21 made of aluminum casting.
0, or the work 30 composed of an engine cylinder block having a bore 32 formed by casting aluminum and having a coating layer 33 formed by thermal spraying of iron on the inner surface of the bore 32 has been described. In an engine cylinder block having a bore formed by casting iron, It can be applied to the inspection of cavities and scratches, and can also be applied to the inner surface inspection of works having other bores.

In the case of the work 30 having the coating layer 33 formed by thermal spraying of iron or the work formed by casting of iron, demagnetization is performed to eliminate the influence of residual magnetic flux, or the residual magnetic flux is made constant. In order to carry out the magnetic saturation treatment for this purpose, it is better to carry out the inspection by the inspection device of the present invention.
More accurate inspection can be performed without being affected by residual magnetic flux.

Further, instead of the rotary encoder 8,
A pulse motor whose rotation angle is known by the number of pulses may be used.

[0044]

As described above, according to the present invention, the rotating body that rotates in the vicinity of the inner surface of the bore of the work having the bore, the magnetic probe provided on the peripheral surface of the rotating body, and the rotating body are rotated. It is provided with a driving means for moving the rotating body and a moving means for moving the rotating body in the axial direction in the work, and detects cavities, scratches, or holes in the coating layer by utilizing eddy current. There is no false alarm due to oil and dirt compared to the optical inspection device of No. 1, there is no safety and health problem of the operator compared to the inspection device using X-ray, and compared to the inspection device using ultrasonic waves. , It is not necessary to submerge the work, it is possible to accurately detect the porosity and scratches on the inner surface of the bore, or the holes in the coating layer in a short time, and in-line inspection is possible by incorporating an inspection device in the production line. Productivity is significantly improved.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of a work inner surface inspection apparatus according to an embodiment of the present invention.

2A is a cross-sectional view of an example of a work to be inspected, and FIG. 2B is a cross-sectional view of a different example of a work to be inspected.

3A is a waveform diagram when the output voltage of the magnetic probe is excessive (probe-workpiece distance 0.4 mm), FIG.
(B) is a waveform diagram when the output voltage of the magnetic probe is proper (probe-workpiece distance 0.5 mm), and (C) is a waveform diagram when the output voltage of the magnetic probe is proper (probe-workpiece).
(Workpiece distance 0.6 mm), (D) is a waveform diagram when the output voltage of the magnetic probe is too small (probe-workpiece distance 0.7 mm).

FIG. 4A is a two-dimensional coordinate diagram in which the output voltage change of the magnetic probe due to the porosity and scratches on the inner surface of the bore of the work is represented by the two-dimensional coordinate data of the rotation angle of the rotating body and the bore length. FIG. 4 is a two-dimensional coordinate diagram showing two-dimensional data of the rotation angle of the rotor and the bore length, which represents the change in the output voltage of the magnetic probe due to the holes of the coating layer formed on the inner surface of the bore of the workpiece.

[Explanation of symbols]

1 Inspection device for inner surface of work 2 rotation axes 3,4 rotating body 5 Magnetic probe 6 Proximity sensor 7 Driving means (driving motor) 8 rotary encoder 9 XY table 10 Moving means (vertical moving means) 11 PC 12 monitors 20, 30 work (engine cylinder block) 21,31 bore 33 Coating layer by thermal spraying of iron A output power waveform A'Porosity and scratch detection signal P1, P2 rotation pulse signal Detected position coordinates of porosity and scratches b Coordinates of hole detection position of coating layer

Claims (4)

[Claims] 1. A rotating body which rotates in the vicinity of an inner surface of a bore of a work having a bore, a magnetic probe provided on a peripheral surface of the rotating body, a driving means for rotating the rotating body, and the rotating body. An apparatus for inspecting an inner surface of a work, comprising: a moving unit that moves the work in an axial direction. 2. The inspection device for the inner surface of the work according to claim 1, wherein a proximity sensor is provided on the peripheral surface of the rotating body. 3. The driving means and the moving means are XY
The work inner surface inspection apparatus according to claim 1 or 2, which is attached to a table. 4. The moving means is set to have a relationship of P ≦ A-0.05 mm, where P is a moving pitch per one rotation of the rotating body and A is a hole diameter size to be detected. The inspection device for an inner surface of a work according to any one of claims 1 to 3, which is characterized.