JP2017187335A - Optical inner face measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate errors due to errors of axial direction feeding accuracy, oscillation of a measuring probe, influence of bearing oscillation of a motor rotationally radiating a light beam, and temperature change or fluctuation in optical system in an optical inner face measurement device to thereby resolve variations of image data or noise, and to implement an accurate and precise accuracy measurement of an inner diameter and inner perimeter face.SOLUTION: An optical inner face measurement device has: an optical fiber that is built in a tube; at least two optical path conversion means in a tip end part of the optical fiber; a motor that causes the two optical path conversion means to be rotationally driven; and a sensor that detects mechanical oscillation in a radial direction of a hard light transmissive reference pipe, which is attached to the tip end part of the tube, and the light transmissive reference pipe is inserted into an inner diameter of a measured object. The two optical path conversion means three-dimensionally radiate the light beam guided from the optical fiber in a circumferential direction and axis direction, and detect reflection light to eliminate every mechanical change and error to allow a highly accurate measurement of an inner perimeter face to be implemented.SELECTED DRAWING: Figure 9

Description

  The present invention allows an optical measurement probe to enter the inner peripheral surface or deep hole inner diameter of an object to be measured, emits a light beam to the inner surface or deep hole bottom surface, captures reflected light three-dimensionally, and observes the internal shape. The present invention relates to an optical inner surface measuring apparatus for measuring dimensions and geometric accuracy.

  For example, the quality of machining finish and geometric accuracy of cylinders for automobile engines greatly affect the power performance and fuel consumption efficiency of automobiles, but these inspections are generally performed by roundness measuring machines, surface roughness meters, and linear scales. It was inspected using a contact-type measuring machine such as a length measuring machine. However, in recent years, optical non-contact measuring machines have been introduced for the purpose of not scratching the object to be measured.

  As a means for observing and inspecting the presence or absence of scratches on the inner surface of an object to be measured in a non-contact manner, an image diagnostic technique (optical imaging technique) is a technique that is widely used in fields such as mechanical devices and medical treatment. For example, in the manufacturing site of precision equipment, as a method of inspection of deep part of deep hole and image diagnosis, in addition to camera observation with a general endoscope, light sensor is used to irradiate the inner surface and detect the intensity of reflected light The method of automatically inspecting the presence or absence of surface flaws as judged by a computer is adopted.

  In the medical field, methods such as X-ray CT capable of observing tomographic images, nuclear magnetic resonance, and OCT images with an endoscope using optical coherence (optical coherence tomography) have been studied for observing affected areas inside the human body. And being used.

  In the field of mechanical devices, a typical structure of an observation device to which a technique for observing scratches or measuring dimensions of an inner peripheral surface by irradiating light to the inner peripheral surface of a machine part having a hole or a precision inner diameter is, for example, These are as shown in Patent Documents 1 to 3.

In the hole shape measuring method and measuring apparatus shown in Patent Document 1, a light beam that has passed through a slit is irradiated obliquely into the small diameter hole (1) of the object to be measured (2) in the document, and the small diameter hole (1) The light reflected from the inner peripheral surface was captured by a camera, and the shape accuracy of the small-diameter hole was read.
However, in this configuration, measurement is possible if the surface of the object to be measured is a smooth surface such as a ring gauge. However, when measuring a general complex-shaped machine part, a small-diameter hole (1 ), The reflected light diverges due to the surface roughness of the inner surface and the scratches on the irregularities, and the camera cannot capture the correct shape, making it impossible to measure with high accuracy. Also, when the object to be measured (2) was longer than expected, the reflected light could not be captured and measurement could not be performed.

Moreover, in the scanning type in-pipe shape inspection apparatus described in Patent Document 2, as shown in FIGS. 1 and 3 in the document, a light beam is scanned in a spiral shape in a non-contact manner, In this document, as shown in FIG. 10, three-dimensional shape data is captured and displayed.
However, this document does not describe a mechanism for rotating and radiating a light beam, and when the rotating motor of the radiation beam rotates at a high speed, the rotating shaft is shaken or non-reproduced and the inner peripheral surface of the object to be measured is collected. There was noise in the cross-sectional shape data. In addition, in order to scan the in-pipe inspection device (10) in a spiral manner, vibrations of a motor and a mechanism system for sliding in the longitudinal direction are generally generated by about 0.01 μm or more, and this noise is included in measurement data. Therefore, the reproducibility of the measured values deteriorated, and nanometer-order high-precision measurement could not be performed.

Further, in the hole shape measuring method shown in Patent Document 3, an optical probe (3) is inserted into the inner peripheral surface of the hole to be measured in the document, and three or more points are measured at the first position of the optical probe. Simultaneously or successively irradiate light, measure the distance from the optical probe to the first position on the inner peripheral surface, and then slide the optical probe (3) in the axial direction to move it to the second position. Later, similarly, the distance to the second position of the inner peripheral surface is measured, the parallelism between the inner peripheral surface of the object to be measured and the optical probe is obtained, and the deviation of the parallelism is corrected to correct the inner diameter of the hole. And calculated the geometric accuracy of roundness.
However, in this configuration, while the optical probe moves in the axial direction or the longitudinal direction from the first position to the second position, the linearity of the linear slider that becomes the moving means (eg, 0.01 μm) is poor. To the extent that the parallelism calculation was out of order. In addition, submicron vibration displacement (for example, about 0.1 μm or more) that occurs when the optical probe is rotated deviates the distance from the optical probe to each position on the inner peripheral surface, so correct correction calculation and high-accuracy measurement Was not done.

Japanese Patent Laid-Open No. 08-233545 JP 05-180627 A JP 2010-236870 A

  The present invention has been made in view of the above-described conventional circumstances, and the problem is that the measurement probe is inserted into the inner peripheral surface or deep hole inner diameter of the object to be measured, or the hole of a long and bent pipe. Rotating and radiating light rays to the inner peripheral surface or deep hole bottom, collecting reflected light three-dimensionally, computer processing, observing 3D image data, measuring dimensions and measuring geometric accuracy. In order to prevent deterioration in measurement accuracy caused by accuracy errors of the feed mechanism that occur when the measurement probe is slid in the axial direction, a configuration that can optically perform three-dimensional scanning without sliding in the axial direction is adopted. . Furthermore, it is to completely eliminate the influence of mechanical vibration of the measurement probe itself that radiates and rotates on the inner circumferential surface of the measurement, and the shaft vibration that occurs on the rotary shaft of the motor for rotation radiation. By solving these problems, an optical inner surface measuring apparatus that eliminates data variability and vibration noise caused by mechanical vibration and enables accurate and accurate three-dimensional measurement of inner diameter and inner peripheral surface is provided. That is.

  One means for solving the above problem is that in an optical inner surface measuring apparatus for measuring the inner peripheral surface of an object to be inspected and measuring the dimensional accuracy using an interference optical method (optical interference method, spectral interference method, etc.), a tube An optical fiber built into the optical fiber, and at least two optical path conversion means at the tip of the optical fiber, each of which has a motor for rotationally driving the two optical path conversion means, and the tip of the tube has a hard translucent property. A reference pipe is attached and has a detecting means for detecting a mechanical vibration in a radial direction of the translucent reference pipe, and the translucent reference pipe portion of the optical probe is inserted into the inner diameter of the test object, Two optical path changing means radiate the light beam guided from the optical fiber three-dimensionally in the circumferential direction and the axial direction, and detect the reflected light.

  According to the present invention, conventionally, it is possible to eliminate the influence of the error in the axial feeding accuracy of the measuring apparatus, the vibration of the measuring probe, and the vibration of the bearing of the motor that rotates and radiates the light beam to the surface to be measured. It is possible to eliminate the influence, thereby eliminating variations in measurement data and noise, and accurately measuring the inner diameter and inner peripheral surface accurately and accurately.

1 is a configuration diagram of an optical inner surface measuring apparatus according to an embodiment of the present invention. Cross-sectional view of the optical probe tip of the optical inner surface measuring device Rotation operation explanatory diagram of the same optical probe Illustration of scanning angle of the same optical probe Illustration of scanning angle of the same optical probe 3D scanning range explanatory diagram of the same optical probe Reference pipe and correction principle explanatory drawing of the optical inner surface measuring device Detection waveform, shaft runout and optical fluctuation elimination principle diagram of the optical inner surface measuring device Reference pipe position detection first method explanatory diagram of the optical inner surface measuring machine Reference pipe vibration detection diagram of the optical inner surface measuring machine Detected waveform of the optical inner surface measuring machine and reference pipe vibration amount elimination principle diagram Illustration of the effect of eliminating the vibration amount of the reference pipe of the optical inner surface measuring machine Second method for detecting the reference pipe position of the optical inner surface measuring machine Reference pipe presser explanatory drawing of the optical inner surface measuring machine

The first feature of the optical inner surface measuring apparatus for observing and measuring a test object using the interference optical method of the present embodiment is that an optical fiber built in a tube and at least two optical path conversions at the tip of the optical fiber. And a motor for rotationally driving the two optical path changing means, and a rigid translucent reference pipe is attached to the tip of the tube, and the radial mechanical vibration of the translucent reference pipe is provided. The light-transmitting reference pipe is inserted into the inner diameter of the object to be examined, and the light beams guided from the optical fiber by the two optical path changing means are three-dimensionally in the circumferential direction and the axial direction. It was configured to emit light and detect the reflected light.
With this configuration, the reflected light from the inner peripheral surface of the test object is introduced through the optical fiber, and the shape data of the inner peripheral surface of the test object obtained by calculating with a computer is obtained in the axial direction of the optical fiber. Three-dimensional data can be collected with the translucent reference pipe fixed without moving, and errors in the axial feed accuracy of the measuring device and vibration of the translucent reference pipe can be eliminated. This eliminates variations in image data and noise, and enables accurate and accurate measurement of the inner diameter and inner peripheral surface.

As a second feature, the shape dimension (radius: S) of the translucent reference pipe is measured in advance, and this data is stored in a computer, and between the measured inner peripheral surface (L1) and the translucent reference pipe. Distance data (L1-L2) is measured by the computer from the detected reflected light, and the distance between the inner peripheral surface to be measured and the translucent reference pipe is added to the dimensional shape data (S) of the translucent reference pipe. The data was added to obtain the radius dimension of the inner peripheral surface to be measured = (S + (L1−L2)).
This configuration eliminates the effects of fluctuations in the interference optical system and the effects of motor runout of the motor that radiates light to the surface to be measured, enabling accurate and accurate measurement of the inner diameter and inner surface of the geometric accuracy. .

As a third feature, the inner peripheral surface contour of the test object and the relative position change amount (± R3) between the translucent reference pipes are detected by a camera, and the dimensional shape data of the translucent reference pipes The radius dimension of the inner peripheral surface to be measured = S + (L1−L2) obtained by adding the distance data between the inner peripheral surface to be measured and the translucent reference pipe to (radius: S). The measurement result was corrected by adding the related position dimension (± R3).
With this configuration and method, even if the translucent reference pipe generates vibration or vibration due to the centrifugal force of the rotating part of the built-in motor, it is possible to measure and cancel out this vibration displacement amount. In addition, the accuracy of the inner peripheral surface can be measured.

As a fourth feature, a distance sensor in which an inner peripheral surface contour of the test object and a relative displacement (± R3) between the translucent reference pipes are attached to a base on which the test object is fixed. It was made to detect with.
With this configuration, even if the translucent reference pipe generates vibration due to the centrifugal force of the rotating portion of the built-in motor, the vibration displacement amount can be offset, and accurate measurement of the inner diameter and the inner peripheral surface is possible. .

As a fifth feature, the tip of the translucent reference pipe 22 is inserted from one side of the hole of the test object 100a, and the reference pipe presser 53 is inserted from the other side of the hole. The light beam is emitted three-dimensionally in the circumferential direction and the axial direction while being in contact with the tip, and the reflected light is detected.
According to this configuration, since the reference pipe presser 53 reduces the amount of fine vibration at the tip of the translucent reference pipe 22, more accurate and accurate measurement of the inner diameter and the inner peripheral surface is possible.

As a sixth feature, the motor includes a first motor and a second motor disposed on the rear side of the first motor, and the optical path conversion means is a first optical path operated by the first motor. There are conversion means and second optical path conversion means operated by the second motor. The optical fiber is integrated with a fixed-side optical fiber disposed in a non-rotatable manner on the tube via a fixture on the rear side of the second motor, and a rotating shaft portion of the first motor or the second motor. And a rotation-side optical fiber that rotates in a straight line. The rotating shaft portions of the first motor and the second motor each have a hollow shape, and at least a part of the rotating side optical fiber is hollow in the rotating shaft portion of the first motor. While being inserted through the hole, at least a part of the rear side is fixed to the hollow hole of the rotating shaft portion of the second motor. The first optical path conversion means is disposed so as to be rotatable integrally with a rotation shaft portion of the first motor on the tip side of the second optical path conversion means, and the second optical path conversion means is The configuration is provided at the tip of the rotation-side optical fiber.
According to this configuration, since the three-dimensional measurement within a certain range can be performed without moving the translucent reference pipe 22 and the tube 6 in the Z-axis direction (longitudinal direction), errors in the axial feed accuracy of the measuring device are completely eliminated. Therefore, highly accurate measurement is possible.

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

An embodiment of an optical inner surface measuring apparatus according to the present invention will be described.
1 to 12 show an embodiment of an optical inner surface measuring apparatus according to the present invention.

  FIG. 1 is a configuration diagram of an optical inner surface measuring apparatus according to an embodiment of the present invention. A stand 81 is fixed to the base 80a, and a slider 82 is moved up and down together with the optical probe 24 by a slider motor 83. The inspection object 100a is set on the base 80a, and the optical probe 24 is configured to enter and exit the deep hole of the inspection object 100a. The light beam that has entered the fixed-side optical fiber 1 passes through the tube 6, further passes through the connection part 84 of the measuring machine main body 85, enters the optical interference analysis part 88, is analyzed by the computer 89, and is displayed on the monitor 90. Display measured values.

  This optical inner surface measuring device has a diameter measuring function, a roundness measuring function, and a cylindricity measuring function that collects the roundness data in a longitudinal direction, combines them, and displays them three-dimensionally. Have.

  FIG. 2 is a sectional view of the tip of the optical probe 24 of the optical inner surface measuring apparatus according to the embodiment of the present invention. The fixed-side optical fiber 1 that guides the light beam from the rear end side to the front end side of the optical probe 24 is inserted into a sufficiently long tube 6 and fixed by the optical fiber fixture 4.

  A rotation-side optical fiber 2 is rotatably disposed on the distal end side of the fixed-side optical fiber 1. The first optical path conversion means 3a, 3b comprising a substantially flat mirror or the like is provided on the further end side of the rotation side optical fiber 2 substantially coaxially by the first motor 12 independently of the rotation side optical fiber 2, and is rotatable. And is configured to emit a light beam in a 360-degree circumferential direction by rotating.

  The end surfaces of the rotation side optical fiber 2 and the fixed side optical fiber 1 face each other with a minute distance of about 5 μm, and the rotation side optical fiber 2 includes the rotating light shielding plate 5 and the optical fiber fixture 4. The fixed optical fiber 1 can maintain a high transmittance and is optically connected with almost no loss.

  Further, the light beam transmitted through the stationary optical fiber 1 and the rotating optical connector 20 is collected and rotated at the tip of the rotating optical fiber 2, and a little angle is given to the tip of the first optical path changing means 3a, 3b while rotating. The second optical path changing means 21 that emits the light is attached.

  In the first motor 12, the first motor coil 7 and the first bearings 9 b and 9 a are fixed to the motor case 8, and the first hollow rotating shaft 10 to which the first rotor magnet 11 is attached rotates. A voltage is applied to the first motor coil 7 from the first electric wire 18, and the first optical path changing means 3 made of a mirror or the like is attached to the rotating first hollow rotating shaft 10.

  Similarly to the first motor 12, the second motor 17 has second bearings 16 a and 16 b and a second motor coil 15 attached to the motor case 8, and the second bearings 16 a and 16 b include the second rotor magnet 14. 2 The hollow rotating shaft 13 is rotatably supported, a voltage is applied from the second electric wire 19, and the rotation-side optical fiber 2 is inserted and fixed in the hole 13 a of the rotating second hollow rotating shaft 13. The 2nd optical path changing means 21 which consists of is attached.

  The first motor 12 shown in FIG. 2 is supplied with electric power from the first motor driver circuit 86 shown in FIG. 1 and driven to rotate. The second motor 17 is supplied with voltage from the second motor driver circuit 87 and driven to rotate. .

  In the vicinity of the outer periphery of the first optical path changing means 3 that emits the light beam, a translucent reference pipe 22 that can transmit the light beam is integrally attached to the tube 6 and the motor case 8. The inner peripheral surface or outer peripheral surface of the translucent reference pipe 22 is coated with a coating or the like for reducing surface reflection and increasing light transmittance as necessary. Further, the first optical path changing means 3 is constituted by a rotatable mirror or prism, and has high reflection efficiency and can reduce the optical loss and perform highly accurate measurement.

  The second optical path changing means 21 is constituted by a prism having a substantially flat surface inclined at the tip, and has high light-collecting properties, and can perform high-precision measurement with reduced optical loss.

  Next, the characteristic operation and effects of the optical inner surface measuring apparatus of FIG. 1 using the above-described three-dimensional scanning optical probe of FIG. 2 will be described in detail.

  In FIG. 1 and FIG. 2, a light beam such as a near infrared ray or a laser beam emitted from the inside of the measuring instrument main body 85 passes through the fixed side optical fiber 1 built in the tube 6.

  When electric power is supplied from the first electric wire 18 and the two motors of the first motor 12 and the second motor 17 are synchronously rotated at the same rotational speed in the range of about 900 to 20,000 rpm, the guided light beam is a rotating optical connector. 20 and the rotation-side optical fiber 2, emitted from the second optical path conversion means 21, reflected by the substantially flat surface portion of the first optical path conversion means 3 a, and changed in direction to a certain angular direction (the angle θ 1 in FIG. 2). In this case, the radiation range is an umbrella-shaped range having an angle θ1 as shown in FIG.

  The light beam further passes through the translucent reference pipe 22, and the light beam reflected from the inner peripheral surface of the inspection object 100a is transmitted through the same optical path in the opposite direction to the translucent reference pipe 22⇒first optical path conversion means 3⇒second. The light path changing means 21 ⇒ the rotation side optical fiber 2 ⇒ the rotation optical connector 20 ⇒ passes through the fixed side optical fiber 1 and is guided to the optical interference analysis unit 88.

  Next, the rotation speed of the first motor 12 and the second motor 17 is, for example, the rotation speed of the first motor 12 is kept constant at 3600 rpm, while the rotation speed of the second motor 17 is kept constant at 3570 rpm. Switch to a rotation state that gives a slight difference in rotation speed. In this state, as shown in FIG. 3, the first optical path conversion unit 3 rotates, and at the same time, the relative rotation angle phase with the second optical path conversion unit 21 gradually changes, and the light beam eventually rotates. The light beam reflected by the means 3 is radiated in the entire circumferential direction at 360 degrees, and the radiation angle in the longitudinal direction gradually changes and changes as indicated by θ2 in FIG. That is, the radiation range of light at this moment has changed to an inclined umbrella-shaped range as shown in FIG.

  This rotation angle phase difference is shifted by 30 rotations (that is, 3600-3570 = 30 rotations / minute) which is a difference from the rotation speed of the second motor 17 while the first motor 12 rotates 3600 times per minute. The rotation angle phase difference is generated 30 times per minute (that is, 30 reciprocations), and the rotation phase difference between the first optical path conversion unit 3 and the second optical path conversion unit 21 is continuously generated 30 times per minute. By this operation, as shown in FIG. 6, the radiation direction of the light beam continuously changes in the range of θ1 to θ2, and the radiation range of the light beam is repeatedly irradiated three-dimensionally in the range of θ1 + θ2. In this configuration, since the signal lines and the electric wires 18 and 19 do not exist within the light emission range, three-dimensional image data having no shadows or omissions can be obtained.

  In FIG. 2, the rotational speed sensor 23a generates one pulse per one rotation of the first optical path changing means 3 or the first hollow rotary shaft 10, and this pulse signal is sent to the first motor driver circuit of FIG. The rotation speed of the first motor 12 is adjusted and sent to the computer 89 to be used as a trigger signal for rendering a three-dimensional digital image for each frame.

  In the optical inner surface measuring apparatus of the present invention, the procedure for measuring the inner diameter of the inspection object 100 is as follows.

  First, calibration (calibration) is performed as preparation before measurement. As shown in FIG. 7, the transparent reference pipe 22 of the optical probe 24 is inserted into the hole of the ring gauge 100 whose inner diameter dimension (D1) is known, and from the outer diameter of the transparent reference pipe 22 to the inner surface of the ring gauge 100. Difference (L1−L2) and (L1′−L2 ′) are displayed on the monitor 90, and the numerical value of the diameter of the translucent reference pipe 22 (D2 = 2 × S = (L1− (L1−L2)) + ( L1 ′ − (L1′−L2 ′)) is obtained, and the numerical value of S is stored as a reference diameter in the computer 89 to complete the preparation.This calibration is periodically performed about once a month. Is.

  When calibration is completed, measurement is started next. The light-transmitting reference pipe 22 portion of the optical probe 24 is inserted into another inspection object 100a, the first motor 12 and the second motor 17 are rotated, and a light beam is emitted so that L1 (reference object from the probe reference) is shown. The distance to the inner surface of the inspection object 100a) and L2 (the distance from the probe reference to the translucent reference pipe 22) are obtained. FIG. 8 shows a graph of the time change of the measured values. Both the measured values of L1 and L2 are the temperature fluctuation of the measuring machine body 85, the instability from the switch ON to the stabilization of the apparatus, and the fluctuation fluctuation. It shows a state that changes greatly with time. However, the distance from the translucent reference pipe 22 to the inspection object 100a is not affected at all, and shows a constant value as shown in the graph of (L1-L2) in FIG. Accordingly, the computer 89 is programmed to calculate and display the true radius measurement = (S + (L1-L2)).

  In addition, as shown in FIG. 7, the cylindricity measurement method is such that the slide motor 83 shown in FIG. 1 is stopped and no vibration is generated. 89 automatically corrects the tilt angle to obtain a radius difference between the two stereoscopic images of the inscribed cylinder and the circumscribed cylinder, and displays this on the monitor 90 as the cylindricity.

  9 to 12 show a first method for detecting the position of the translucent reference pipe 22 of the optical inner surface measuring apparatus according to the present invention.

  The configuration of FIG. 9 is the same as that of FIG. 7, but the camera 51 is fixed to the base 80 so that the relative position of the camera 51 with respect to the inspection object 100b does not change. FIG. 10 is an image detected by this camera, and shows the contour 100x of the inner surface of the inspection object 100b and the center of the translucent reference pipe 22. The center position of the translucent reference pipe 22 is always slightly vibrated. The amount of vibration is captured as indicated by ± R3 (specifically about 0.01 μm) in the figure. This slight vibration is mainly due to unbalance vibration generated by the rotation of the first motor 12 and the second motor 17 shown in FIG. 2, and the amount of vibration is reduced by reducing the dynamic unbalance amount of these two motors. Although it decreases, it is very effective to detect the vibration of the translucent reference pipe 22 in order to perform measurement with higher accuracy.

FIG. 11 is a diagram for explaining the detection waveform and the reference pipe vibration amount exclusion principle. In the figure, the graph of ± R3 shows the change over time of the detected vibration amount of the translucent reference pipe 22, and L1, L2, (L1-L2) These three graphs are the same as in FIG. When the computer 89 measures the inner diameter of the inspection object 100b, it is calculated by adding ± R3 to the radius measurement value = (S + (L1-L2)) described above.
That is, true radius measurement = S + (L1-L2) ± R3,
This is a highly accurate true measurement value.

According to our experiment, as shown in FIG.
(I) In the measurement without using the light-transmitting reference pipe, the measurement variation was large due to the fluctuation of the optical system and the influence of the vibration of the rotary motor, and the standard deviation (σ) was very bad at 18.5 μm.
(II) However, as shown in FIG. 7, in the method of measuring the distance from the translucent reference pipe 22 to the inner peripheral surface of the inspection object 100a, the standard deviation (σ) is greatly improved to 0.05 μm,
(III) Further, as shown in FIG. 9, when the vibration of the translucent reference pipe 22 itself is captured by the camera 51 and this is taken into consideration, the standard deviation (σ) is improved to 0.02 μm. It was possible to measure with very high accuracy without measurement variation.

  With this configuration, the computer 89 calculates the reflected light introduced from the inner peripheral surface of the object 100a to be inspected through the optical fiber 1, so that the measurement can be performed based on the translucent reference pipe, and the slider 82 is stationary. Three-dimensional data can be collected, and the vibration of the translucent reference pipe is detected and corrected using this, so fluctuations or fluctuations due to the temperature of the interference optical system, etc. The effects of bearing runout of the rotating radiation can be completely eliminated, errors in the axial feed accuracy of the measuring device can be eliminated, and measurement can be performed with high accuracy without variation.

FIG. 13 shows a second embodiment of the optical surface measuring apparatus according to the present invention.
The configuration in FIG. 13 is almost the same as that in FIG. 9, but the distance sensors 52 a and 52 b measure the relative positional relationship between the object 100 C to be inspected and the light-transmitting reference pipe 22 from two directions, and transmit light to the object 100 to be inspected. The change (± R3) of the center position of the sex reference pipe 22 is detected.

  Similarly to FIG. 9, when measuring the inner diameter dimension of the inspection object 100 </ b> C, the computer 89 calculates by adding ± R3 to the previously described radius measurement value = (S + (L1−L2)). As a result, the standard deviation (σ) of the measured value was improved to 0.02 μm as shown in FIG. 12C as in FIG. 9, and very high-precision measurement without measurement variation was performed.

FIG. 14 shows a third embodiment of the optical surface measuring apparatus according to the present invention.
The configuration of FIG. 14 is almost the same as that of FIG. 7, but the tip of the light-transmitting reference pipe 22 is inserted from one side of the hole of the test object 100d, and the reference pipe presser 53 is inserted from the other side of the hole. It is configured to emit light rays three-dimensionally and detect the reflected light in a state in which the light-transmissive reference pipe is prevented from shaking by being brought into contact with the tip of the light-sensitive reference pipe 22.

  According to this configuration, there is an effect that the rotating portions of the first motor 12 and the second motor 17 in which the translucent reference pipe 22 is incorporated reduce vibration. In this method, vibrations in the high-frequency region, which the camera 51 and the distance sensor 52 are not good at detecting, can be greatly reduced, so that more accurate measurement is possible.

  The tube 6 has a diameter of about 2 mm or less, and the fixed-side optical fiber 1 that penetrates the tube 6 is a bendable glass fiber having a diameter of about 0.85 to 0.4 mm.

  The first optical path changing means 3 shown in FIG. 2 is composed of a mirror or a prism having a smooth reflecting surface, and its surface roughness and flatness are polished to an accuracy equal to or higher than that of general optical components in order to increase the reflectance. Yes.

  The first hollow rotary shaft 10 shown in FIG. 2 is made of metal or ceramics, and is formed into a hollow shape by drawing with a die of molten metal or extrusion with a die of ceramics before firing. Finished by etc.

  In FIG. 2, the hole of the first hollow rotating shaft 10 has a diameter of 0.15 to 0.5 mm and is sufficiently larger than the diameter of the optical fiber 1, so that the fixed-side optical fiber 1 fixed by the optical fiber fixture 4 is the first one. 1 The hollow rotating shaft 10 is not contacted, and even if lightly touched, wear powder is not generated. Further, there is no problem that the rotational friction torque varies in this portion.

  According to the present invention, conventionally, errors in the axial feed accuracy of the measuring apparatus, vibrations of the translucent reference pipe for measurement, and vibration of the motor bearing that radiates light to the surface to be measured, and thermal fluctuations of the optical system, The effects of fluctuations can be completely eliminated, thereby eliminating variations in image data and noise, enabling accurate and accurate measurement of the inner diameter and inner peripheral surface, and the high accuracy of the inner peripheral surface shape of the object being measured. Measurements can be made.

  The optical inner diameter measuring apparatus for observing and measuring a test object using the interference optical method of the present invention can be applied to an industrial diagnostic apparatus to perform highly accurate measurement, for example, three-dimensional observation of deep holes. It can be performed. In addition, it is expected to be used for numerical diagnosis and treatment of minute lesion dimensions in the medical field.

DESCRIPTION OF SYMBOLS 1 Fixed side optical fiber 2 Rotation side optical fiber 3a, 3b 1st optical path conversion means (mirror)
4 Optical fiber fixture 5 Shield plate 6 Tube 7 First motor coil 8 Motor case 9a, 9b First bearing 10 First hollow rotating shaft 11 First rotor magnet 12 First motor 13 Second hollow rotating shaft 13a Hole 14 Second rotor Magnet 15 Second motor coils 16a and 16b Second bearing 17 Second motor 18 First electric wire 19 Second electric wire 20 Rotating optical connector 21 Second optical path conversion means (prism etc.)
22 translucent reference pipe 23a rotational speed sensor 24 optical probe 51 camera (relative position detecting means)
52a, 52b Distance sensor 53 Reference pipe presser 55 Scanning range 80, 80a, 80b, 80c Base 81 Stand 82 Slider 83 Slider motor 84 Connection portion 85 Measuring machine main body 86 First motor driver circuit 87 Second motor driver circuit 88 Light Interference analysis unit 89 Computer 90 Monitor 100 Inner diameter ring gauges 100a, 100b, 100c, 100d Inspected object 100x Inner peripheral surface contour

Claims (6)

In an optical inner surface measurement apparatus that observes and measures a test object using an interference optical method,
An optical fiber built into the tube,
Having at least two optical path changing means at the tip of the optical fiber;
A motor that rotationally drives the two optical path changing means;
A hard translucent reference pipe is attached to the tip of the tube,
Having a sensor for detecting radial mechanical vibration of the translucent reference pipe;
Insert the translucent reference pipe into the inner diameter of the test object,
An optical inner surface measuring apparatus characterized in that the two light path changing means emit light rays guided from the optical fiber three-dimensionally in the circumferential direction and the axial direction and detect the reflected light.
The shape dimension (S) of the translucent reference pipe is measured in advance and this data is stored in a computer.
The distance data (L1-L2) between the measured inner peripheral surface (L1) and the translucent reference pipe is measured from the detected reflected light by a computer,
Radial dimension of the inner peripheral surface to be measured = S + (L1-L2) by adding distance data between the inner peripheral surface to be measured and the translucent reference pipe to the dimension / shape data (S) of the translucent reference pipe The optical inner surface measuring apparatus according to claim 1, wherein:
The inner peripheral surface contour of the test object and the relative position change amount (± R3) between the translucent reference pipe are detected by a camera,
Radial dimension of the inner peripheral surface to be measured, which is obtained by adding distance data between the inner peripheral surface to be measured and the translucent reference pipe to the dimension / shape data (S) of the translucent reference pipe = S + (L1-L2) In addition, correction is made by adding a relational position dimension (± R3) between the translucent reference pipes, and a radius dimension of the inner peripheral surface to be measured = S + (L1−L2) ± R3 is obtained and displayed. The optical inner surface measuring apparatus according to claim 1 or 2.
Detecting a relative displacement (± R3) between the inner peripheral surface contour of the test object and the translucent reference pipe with a distance sensor attached to a base to which the test object is fixed. The optical inner surface measuring apparatus according to any one of claims 1 to 3.
Insert the tip of the translucent reference pipe from one of the holes of the test object,
A configuration in which a reference pipe presser is inserted from the other side and in contact with the tip of the translucent reference pipe, the light beam is emitted three-dimensionally in the circumferential direction and the axial direction, and the reflected light is detected. The optical inner surface measuring device according to any one of claims 1 to 4, wherein
  The motor includes a first motor and a second motor disposed on the rear side of the first motor, and the optical path conversion unit includes a first optical path conversion unit operated by the first motor, and the second motor. There is a second optical path changing means that is operated by a motor, and the optical fiber is arranged on the rear side of the second motor via a fixture so as not to rotate on the tube, and the first motor or The rotation shaft portion of the second motor and a rotation-side optical fiber that rotates integrally, each of the rotation shaft portions of the first motor and the second motor has a hollow shape, The rotation-side optical fiber has at least a part on the tip side inserted into the hollow hole of the rotation shaft part of the first motor, and at least a part on the rear side fixed to the hollow hole of the rotation shaft part of the second motor. The first optical path conversion means is disposed so as to be rotatable integrally with a rotation shaft portion of the first motor on the tip side of the second optical path conversion means, and the second optical path conversion means is The optical inner surface measuring apparatus according to claim 1, wherein the optical inner surface measuring apparatus is provided at a distal end of the rotation-side optical fiber.

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