JP2021156852A - Device and method for optical inner surface measurement - Google Patents

Abstract

To precisely and rapidly measure the shape and the depth of irregular scratches of the inner periphery surface of a hole in a measurement target object.SOLUTION: Optical concentration information of the inner periphery surface of a hole in a measurement target object is acquired from a camera image as first measurement means, the position in a depth direction of irregular scratches of the inner periphery surface of the hole in the measurement target object is specified from the concentration information, a rotary light scan probe as second measurement means is caused to invade to near the specified position in an advanced manner, light reflected by the inner periphery surface is taken in three-dimensionally near the position, and the shape and the depth of irregular scratches are measured minutely.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical inner surface measuring device and a measuring method, and in particular, observes scratches and the like on the inner peripheral surface of a hole of an object to be measured, and makes shape / depth dimensions and geometric accuracy highly accurate. It is to measure.

For example, the finished dimensions and geometric accuracy of automobile engine cylinders and automobile brake master cylinders, as well as the presence of surface scratches and cavities, greatly affect the power performance and fuel consumption efficiency of automobiles. Conventionally, scratch inspection has been performed visually with a contact-type measuring machine such as an inner diameter measuring machine and a roundness measuring machine.

However, in recent years, optical non-contact measuring instruments have been introduced for the purpose of not damaging the object to be measured. They irradiate light rays and capture the reflected light with an optical sensor, and the arrival time and wavelength of the reflected light, or optical interference. A method is adopted in which measurement data of the state of occurrence of fringes is acquired, calculated by a computer, and the three-dimensional shape of the inner peripheral surface is automatically inspected. Further, such a non-contact measuring machine can measure the size and depth of unevenness on the inner surface as long as the entire inner peripheral surface is scanned for a long time. For example, Patent Documents 1 and 2 show typical structures of observation devices to which a technique of irradiating the inner peripheral surfaces of mechanical devices and mechanical parts with light rays to observe or measure the inner peripheral surfaces is applied.

In the scanning tube shape inspection device shown in Patent Document 1, a light beam is spirally radiated into a tube having a length, and the entire surface is scanned to detect unevenness while setting a constant threshold value for the detected unevenness depth. The amount of data saved in the computer is increased by recognizing the measured value exceeding this as a defect (Fig. 10 in the document), storing the data only in the vicinity of the area determined to be defective in the computer, and not storing the other data. We have succeeded in reducing it.
However, in the method of the document, a fine light ray having a spot diameter of about 20 μm is emitted to the entire inside of the tube to detect the position of the defect and its size and depth. However, when the length of the tube is 150 mm and the spot diameter of the light beam is 20 μm, rotational scanning for 7500 laps is required and the measurement takes a long time. For example, assuming that it takes 1 second to scan one lap, a long inspection of 7500 seconds (2 hours) is required, and it is possible to reduce the capacity of storing data in the computer, but the measurement time In terms of points, it could not be put to practical use at all.

Further, in the invention described in Patent Document 2, in order to measure the inner peripheral surface of the object to be measured (bearing 9), a light ray (26) is emitted and condensed inside a pipe-shaped translucent member (21). It has a built-in first optical path conversion member (3) consisting of a lens (24) and a rotating mirror. Then, as shown in FIGS. 8 and 9, vibration during rotation is detected and corrected to perform highly accurate measurement of the inner peripheral surface.
However, the configuration described in Patent Document 2 is the same as that in Patent Document 1, and defects cannot be detected by radiating fine light rays having a spot diameter of about 20 μm over the entire tube. Therefore, long-term inspection was required and it was not industrially practical.

Patent No. 3066813 Patent No. 6232550

The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to measure scratches on the inner peripheral surface of a hole provided with an object to be measured with high accuracy and in a short time. ..

One means for solving the above problem is to acquire a shadow image that appears by illuminating the inner peripheral surface of a hole provided in the object to be measured as an optical inner surface measurement method, and to obtain a shadow image that appears from the shading information of the shadow image. Identify the location of uneven scratches on the peripheral surface. Then, an optical scanning probe is placed in the vicinity of the specified position, and the reflected light of the light beam emitted from the optical scanning probe toward the inner peripheral surface is three-dimensionally captured to measure the shape dimension and depth of the uneven scratch. Is.

Further, as an optical measuring device that can use this measuring method, the inner surface of the hole is measured by the first measuring means for acquiring a shadow image formed on the inner surface of the hole of the object to be illuminated and the interference optical method. It is provided with a second measuring means.

According to the present invention, the measurement time when measuring the state of the inner peripheral surface of the hole of the object to be measured in detail can be significantly shortened as compared with the conventional case.
For example, conventionally, when the shape and depth of uneven scratches on the inner peripheral surface of a hole to be measured are measured in detail with high accuracy, the entire inner peripheral surface is detected and precisely measured by a rotary optical scanning probe, for example, over 2 hours. It is possible to measure within about 1 minute compared to what was done.

Configuration diagram of the camera-integrated optical probe of the optical inner surface measuring device of the present invention Camera unit of the optical inner surface measuring device of the present invention Overall configuration diagram of the optical inner surface measuring device of the present invention Operation block diagram of the optical inner surface measuring device of the present invention Example of camera shading data stereoscopic acquisition of the optical inner surface measuring device of the present invention Development view of the inner peripheral surface shading image of the optical inner surface measuring device of the present invention Inner peripheral surface shading position analysis diagram of the optical inner surface measuring device of the present invention Three-dimensional shape acquisition data diagram by the second measuring means of the optical inner surface measuring device of the present invention Explanatory drawing of operation of the first and second measuring means of the optical inner surface measuring apparatus of this invention Positional relationship diagram of the camera and the light of the optical inner surface measuring device of the present invention 2nd Example block diagram of the optical inner surface measuring apparatus of this invention

The first feature of the optical inner surface measuring device according to the present embodiment is that a probe is inserted into a hole provided in an object to be measured to measure the inner surface of the hole, and the inner surface of the illuminated hole is measured. It is provided with a first measuring means for acquiring a shadow image that can be formed and a second measuring means for measuring the inner surface of a hole by an interferometric method (optical interference method, spectroscopic interference method, etc.).
With this configuration, the position of the shadow image such as uneven scratches detected by the first measuring means can be measured in detail by the second measuring means, so that the probe of the second measuring means covers the inner peripheral surface over the entire length of the hole. There is no need to measure. Therefore, the probe of the second measuring means is fast-forwarded to the position of the uneven scratch specified by the first measuring means, and the precision measurement is performed only at the position where the precision measurement is required, so that the measurement time can be dramatically shortened.

The second feature is that the first measuring means acquires the optical shading information of the inner peripheral surface of the hole to be measured from the camera image, analyzes the shading information, and analyzes the image to determine the position in the depth direction of the uneven scratch on the inner peripheral surface of the hole to be measured. To identify.
As a result, the position of the uneven scratch on the inner peripheral surface of the hole to be measured can be found in an extremely short time, and the position can be specified.

The third feature is that the camera constituting the first measuring means is fixedly arranged at the end of the probe.
According to this configuration, with respect to the probe to be inserted into the hole to be measured, the camera is integrally arranged at the insertion side end portion, so that the work of setting and measuring the device becomes easy. Further, a lighting means such as an LED light may be arranged according to the insertion side end portion.

The fourth feature is that a conical mirror is attached to the end of the probe.
According to this configuration, the camera can capture an image of the inner peripheral surface of the measurement target hole reflected on the conical mirror in a state where the camera is arranged outside the measurement target hole.

As a fifth feature, the second measuring means is arranged in an optical fiber that radiates a light beam from the tip, a translucent and substantially cylindrical pipe, and a translucent pipe on the tip side of the optical fiber and inside the translucent pipe. It includes an optical path conversion means and a motor for rotationally driving the optical path conversion means. Then, a light beam is rotationally radiated to the inner peripheral surface of the hole via an optical path conversion means, and interference light is generated from this reflected light to measure the distance three-dimensionally.
According to this configuration, since the translucent pipe can be used as a reference in the acquisition of the three-dimensional shape data, the mechanical runout or non-reproducible runout of the rotating shaft or rotating portion that radiates on the inner peripheral surface is caused. Rotational vibration and noise can be removed, and correct 3D shape data of the inner peripheral surface can be obtained.

The sixth feature is that when the second measuring means performs the measurement, the cross-sectional shape and dimensional data of the translucent pipe is measured in advance at the calibration stage and stored in the computer. Then, when measuring the dimensions of the object to be measured, the reflected light radiated by rotation is captured and the radius distance (ΔR1, ΔR2) from the inner peripheral surface or outer peripheral surface of the translucent pipe to the inner peripheral surface of the object to be measured. By calculating the diameter (D = D0 + ΔR1 + ΔR2) from the diameter value (D0) of the three-dimensional shape of the translucent pipe stored in the computer in advance, the effects of rotational runout and rotational vibration of the optical path conversion means are excluded. The corrected three-dimensional shape data is collected and calculated.
As a result, the inner peripheral surface measurement of the second measuring means can always be compared with the translucent pipe whose dimensions have been precisely calibrated, and the measurement repeatability is very good. You get the opportunity.

As a seventh feature, the rotating shaft portion of the motor has a hollow shape, and an optical fiber is inserted into the hollow hole of the rotating shaft so as to be rotatable relative to the rotating shaft.
According to this configuration, light rays are emitted three-dimensionally by the rotation of the motor, and three-dimensional shape data can be collected. Since there is no shadow, there is no omission in the collected data, so high-precision calculation by computer is possible.

One of the features of the optical measurement method according to the present embodiment is to acquire a shadow image that appears by illuminating the inner peripheral surface of a hole provided in the object to be measured, and obtain an inner circumference from the shading information of the shadow image. Identify the location of uneven scratches on the surface. Then, an optical scanning probe is placed in the vicinity of the specified position, and the reflected light of the light beam emitted from the optical scanning probe toward the inner peripheral surface is three-dimensionally captured to measure the shape, dimension and depth of the uneven scratch. It is in.
By this method, it is possible to measure scratches on the inner peripheral surface of the hole provided with the object to be measured with high accuracy and in a shorter time than before.

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

A first embodiment of the optical inner surface measuring device according to the present invention will be described.
1 to 3 show an embodiment of an optical inner surface measuring device according to the present invention.

FIG. 1 is a configuration diagram of a camera-integrated optical probe of the optical inner surface measuring device of the present invention.
The motor 10 includes bearings 9a and 9b, a motor coil 7, a hollow rotating shaft 5, and a rotor magnet 8 fixed to the hollow rotating shaft 5. Power is supplied from the motor driver circuit 86 shown in FIG. 3 through an electric wire 12 to rotate the motor 10. .. In FIG. 1, a light ray 13 is guided to an optical fiber 1 built in a tube 6. If necessary, a condensing lens 2 made of a spherical lens or the like is provided at the tip of the optical fiber 1, and light rays 13 are emitted toward the optical path conversion means 3. The tip side of the optical fiber 1 is rotationally driven by a motor 10 and has an optical path conversion means 3. The optical path conversion means 3 is built in a translucent pipe 4, and the translucent pipe 4 and the optical path conversion means 3 are It is inserted into the inner peripheral surface 61a of the object to be measured 61 having a substantially cylindrical shape.

FIG. 2 shows a camera unit of the optical inner surface measuring device of the present invention. In the camera unit, a camera 15 to which a fisheye lens 14 is attached is fixed to, for example, a lower end surface of the optical probe 11 of FIG. A battery 16 is also integrally attached to the optical probe 11 of the camera 15 if necessary.

FIG. 3 is an overall configuration diagram of the optical inner surface measuring device according to the embodiment of the present invention. The stand 81 is fixed to the base 80, and the slider 82 moves up and down together with the optical probe 11 by the slider motor 83. The object to be measured 61 is set in a centering jig 79 fixed to the base 80, and the optical probe 11 goes in and out of the deep hole 61a of the object to be measured 61. The light beam entering the optical path conversion means 3 (mirror or prism) of the probe 11 passes through the tube 6, further passes through the connection portion 84 of the measuring machine main body 85, enters the optical interference analysis unit 88, and enters the computer 89. The calculation result is displayed on the monitor 90.

Hereinafter, the operation and operation of the present invention will be described with reference to FIGS. 4 to 9.

FIG. 4 is an operation block diagram of the measuring method and the measuring device in this embodiment.
The measurement is performed according to the following procedure.

[1] Work set In FIG. 3, the object to be measured 61 is set on the centering jig 79.

[2] Camera image acquisition In FIG. 3, by operating the slider motor 83, the portion of the translucent pipe 4 of the optical probe 11 is inserted into the inner peripheral surface 61a of the hole of the object to be measured 61. In FIG. 1, the fisheye lens 14 and the camera 15 photograph the inner peripheral surface 61a, and acquire image data in the range shown in ΔZ = 1 to 5 mm in the drawing. When the slider motor 83 is continuously operated, the camera acquires the image shown in FIG. 5, and this data is converted into the developed view data of FIG. FIG. 10 shows the positional relationship between the inner peripheral surface 61a, the concave scratch 61b, and the lower illumination 22, and the portion indicated by ΔL in the drawing becomes a shadow portion, which is detected by the camera 15. The inner peripheral surface 61a and the concave scratch 61b are illuminated by the LED light 17 in FIG. 1 or the downward illumination 22 in FIG.

[3] Camera image analysis In the developed view of the camera image shown in FIG. 6, the angle is divided into four equal parts as shown in the drawings (A) to (D), and in the depth direction, for example, from Z = 0 mm to Z = MAX. By dividing the space with a certain width, it is divided into a large number of frames of 4 × MAX, the area ratio (%) of the shaded area in each frame is obtained, and the inner peripheral surface shading position analysis as shown in FIG. Get the figure. The graphs shown as ΣA to D (360 °) in the figure show the total value for each Z position in the graphs (A) to (D).

[4] Z stage fast forward (1st time)
In FIG. 3, the slider motor 83 is obtained from the shaded portion 78 of the camera image first, and the first position (Z11 to Z12) and the second position of the uneven scratch 61b clearly shown in the shading position analysis diagram of FIG. The slider 82 is fast-forwarded to (Z21 to Z22) and, if necessary, to other positions (Z31 to Z32).

[5] Measurement of inner peripheral surface by optical interference at the first position In FIG. 9, the light emitting portion of the light probe 11 of the optical probe 11 is located at Z = 11 to 12 in the figure (that is, the inner peripheral surface shading position analysis diagram (FIG.)). It is sent to the scratch detection position) of 7), and in the vicinity of this position, the optical probe 11 precisely scans the inner peripheral surface 61a including the concave scratch 61b by the optical interferometry to acquire three-dimensional data.
In FIG. 1, the diameter (D0) of the inner peripheral surface or the outer peripheral surface of the translucent pipe 4 and the three-dimensional shape data or the two-dimensional cross-sectional shape data are obtained in advance by an operation called calibration and stored in a computer. ..
When measuring the dimensions of the object to be measured, the reflected light 13 rotated and emitted in FIG. 1 is captured, and the radial distance from the inner peripheral surface or the outer peripheral surface of the translucent pipe 4 to the inner peripheral surface of the object to be inspected ( By calculating the diameter (D = D0 + ΔR1 + ΔR2) from ΔR1 and ΔR2) and the three-dimensional shape data (D0) of the translucent pipe stored in the computer in advance, the rotational runout and rotational vibration of the optical path conversion means Eliminate the effects and collect correct dimensional data.
In the past, the amount of runout of the rotating shaft of the motor changed depending on the temperature environment, etc. However, for example, if the amount increased or decreased by 0.1 μm, the measured inner diameter measured by the same amount changed, and correct measurement could not be performed. In the present invention, since the measurement is always based on the translucent pipe 4, the change in runout does not affect the measured value at all, and the correct measurement is possible.

[6] Z stage fast forward (second time)
In FIG. 3, the slider motor 83 moves the slider 82 again in fast forward toward the second position (Z21 to Z22) of the uneven scratch 61b previously obtained from the shaded portion 78 of the camera image.

[7] Measurement of inner peripheral surface by light interference at the second position In FIG. 1, the light emitting portion of the light beam 13 of the optical probe 11 slides, and the movement of the inner peripheral surface shading position analysis diagram Z = 21 to Z = 22 in FIG. In the vicinity of this position, the optical probe 11 precisely scans the inner peripheral surface 61a including the concave scratch 61b by the optical interferometry method to acquire three-dimensional data.

[8] Analysis of optical interference data The inner peripheral surface measurement data of the optical interferences in the above [5] and [7] are shown in the three-dimensional shape acquisition data diagram shown in FIG. Can be shown.

[9] Result display 1
From the acquired measurement data due to optical interference, the area ratio (%) of the uneven defect portion 61b to the total surface area of the inner peripheral surface 61a is displayed.

[10] Result display 2
From the acquired measurement data due to optical interference, the size of the area of the uneven defect portion 61b and the depth of the concave portion are displayed.

[11] End The series of measurements is completed, and the measurement result data is stored in the storage device in the computer.

A second embodiment will be described.
FIG. 11 is a configuration diagram of a second embodiment of the optical inner surface measuring device of the present invention, but the position of the camera 23 is different from that of the embodiment of FIG. A conical mirror 18 is attached to the lower bottom surface of the optical probe 11, and the camera 23 can recognize the shadow portion 78 by capturing an image of the inner peripheral surface 61a reflected on the conical mirror 18.
Other operations are the same as those of the first embodiment shown in FIGS. 1 and 9, and the description thereof will be omitted.

In FIG. 1, D0 is the inner diameter dimension of the translucent pipe, D indicates the diameter at which the light beam 13 is emitted, and the range is a radius of about 1 to 100 mm (mm).

The tube 6 has a diameter of about 1 to 10 mm, and the fixed-side optical fiber 1 penetrating inside the tube 6 is a flexible glass fiber having a diameter of about 0.1 to 0.2 mm. There is.

In FIG. 1, the hole of the hollow rotating shaft 5 has a diameter of 0.2 to 0.3 mm, which is sufficiently larger than the diameter of the optical fiber 1, so that the optical fiber 1 rarely comes into contact with the hollow rotating shaft 5, and is assumed to be. Even light contact does not generate wear debris. Further, there is no problem that the rotational friction torque fluctuates.

According to the present invention, conventionally, when the shape and depth of uneven scratches on the inner peripheral surface of a hole to be measured are measured in detail, the entire inner peripheral surface is detected by a rotary optical scanning probe over, for example, 2 hours for precise measurement. The camera image analyzer of the first measuring means quickly identifies the position of the uneven scratch, and the optical probe of the optical measuring device of the second measuring means penetrates to the vicinity of the specific position at high speed. In order to observe the internal shape of the uneven scratches and measure the dimensions and geometric accuracy and the depth of the scratches only at the specified positions, the shape and depth of the uneven scratches are finely measured within, for example, about 1 minute. can do.

The optical inner diameter measuring device using the interference optical method, which is integrated with the uneven scratch position detection function by the camera of the present invention, is used for high-precision measurement and manufacturing of engine cylinder bores, sintered bearings, dynamic bearings, etc. in industrial applications. Widely used for on-site process inspection.

1 Optical fiber 2 Condensing lens 3 Optical path conversion means (mirror or prism)
4 Translucent pipe 5 Hollow rotating shaft 5a Holder part 6 Tube 7 Motor coil 8 Rotor magnet 9a, 9b Bearing 10 Motor 11 Optical probe 12 Wire 13 Ray 14 Fish-eye lens 15 Camera 16 Battery 17 LED light 18 Conical mirror 19 Receiver 20 Radio wave 21 Camera communication line 22 Downward light 61 Object to be measured 61a Inner peripheral surface 61b Dent 78 Shading part 79 Centering jig 80 Base 81 Stand 82 Slider 83 Slider motor 84 Connection part 85 Measuring machine body 86 Motor driver circuit
87 Optical interference analysis unit 88 Image analyzer 89 Computer 90 Monitor

Claims (8)

An optical inner surface measuring device that measures the inner peripheral surface of a hole by inserting a probe into a hole provided in the object to be measured.
A first measuring means for acquiring a shadow image formed on the inner peripheral surface of the illuminated hole,
An optical inner surface measuring device including a second measuring means for measuring the inner peripheral surface of the hole by an interference optical method. The first measuring means acquires optical shading information of the inner peripheral surface of the hole of the object to be measured from a camera image, analyzes the shading information, and analyzes the shading information in the depth direction of uneven scratches on the inner peripheral surface of the hole. The optical inner surface measuring device according to claim 1, wherein the position is specified. The optical inner surface measuring device according to claim 1 or 2, wherein a camera constituting the first measuring means is fixedly arranged at an end portion of the probe. The optical inner surface measuring device according to claim 1 or 2, wherein a conical mirror is attached to an end portion of the probe. The second measuring means includes an optical fiber that radiates a light beam from the tip, a translucent and substantially cylindrical pipe, and an optical path conversion means that is located on the tip side of the optical fiber and is arranged inside the translucent pipe. A motor for rotationally driving the optical path conversion means,
The invention according to any one of claims 1 to 4, wherein the light beam is rotationally radiated from the reflected light to the inner peripheral surface of the hole through the optical path conversion means, and interference light is generated from the reflected light to measure the distance three-dimensionally. Optical inner surface measuring device. The cross-sectional shape dimensional data of the translucent pipe is stored in a computer in advance, and then
When the second measuring means measures the inner peripheral surface of the hole, it captures the reflected light radiated by rotation, and the radial distance from the inner peripheral surface or the outer peripheral surface of the translucent pipe to the inner peripheral surface of the hole ( The diameter (D = D0 + ΔR1 + ΔR2) is calculated from ΔR1, ΔR2) and the diameter value (D0) of the three-dimensional shape of the translucent pipe stored in the computer in advance.
The optical inner surface measuring apparatus according to claim 5, wherein the corrected three-dimensional shape data excluding the influence of the rotational runout and the rotational vibration of the optical path conversion means is collected and calculated. The optical inner surface measuring device according to claim 5 or 6, wherein the rotating shaft of the motor has a hollow shape, and the optical fiber is inserted into the hollow hole of the rotating shaft so as to be rotatable relative to the rotating shaft. A shadow image that appears by illuminating the inner peripheral surface of the hole provided in the object to be measured is acquired, and the position of the uneven scratch on the inner peripheral surface is specified from the shading information of the shadow image.
An optical scanning probe is arranged in the vicinity of the specified position, light rays are irradiated from the optical scanning probe toward the inner peripheral surface, and the reflected light from the inner peripheral surface is taken in three-dimensionally to obtain the uneven scratch. An optical inner surface measuring method for measuring shape dimensions and depth.

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