JP2010236870A - Hole shape measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hole shape measuring method which accurately measures a hole shape even for a tapered hole and even when the axial line of a hole is inclined. <P>SOLUTION: Simultaneous or successive measuring beams are applied to three or more points on a hole peripheral surface as a first measurement position. The reflected light is guided to an imaging lens through a light guide member and is guided to a light receiving element. On the basis of the light receiving position of the light receiving element, the distances a, b, c, ... from the axial line of an optical probe to the hole inner peripheral surface are determined. The optical probe is moved to a second measurement position in the probe axial direction, and the distances a1, b1, c1, ... from the axial line of the optical probe to the hole inner peripheral surface are determined in the same manner as described above. For the obtained distances, when the ratios of a to a1, b to b1, c to c1, ... are different from each other, it is determined that the axial line of the optical probe and the axial line of the hole do not match, and the inclination angles between a and a1, b and b1, c and c1, ... are determined. The deviation of the measurement positions is corrected from the inclination angles, and the hole inner diameters of the first and second measurement positions from the center of the first and second measurement positions are determined, thereby obtaining the hole shape. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hole shape measuring method capable of accurately measuring a hole shape in which a draft angle is formed as in an aluminum die cast product.

  Conventionally, as a measurement of the hole shape, a laser beam is irradiated on the inner surface of the hole, the reflected light from the inner surface of the hole is received by the optical position detection element, and the dimension between the inner surface of the hole and the reference line of the apparatus based on the received position. (For example, refer to Patent Document 1). Also, there is a type in which basic light is irradiated from the probe to the inner wall surface of the object to be measured, scattered light reflected by the inner wall surface is received by a light receiving element, and the inner diameter of the hole is calculated based on the light receiving position (for example, Patent Documents) 2).

  However, in the measurement of the hole shape according to Patent Documents 1 and 2, there is a problem that the hole shape cannot be measured when the hole is tapered or the axis of the hole is deviated from the axis of the device.

JP 7-260439 A JP 2008-157635 A

  An object of the present invention is to provide a hole shape measuring method capable of accurately measuring a hole shape even if the hole is a tapered hole or the axis of the hole is deviated.

  The present invention relates to a hole shape measurement in which an optical probe is inserted into a hole in a hole formed in a molded product so as to coincide with the axis, and the hole inner surface is irradiated with measurement light to measure the hole shape. In this method, three or more points on the circumferential surface of the hole serving as the first measurement position are irradiated with measurement light simultaneously or sequentially, and the reflected light from the hole inner surface is guided to the imaging lens by the light guide member and guided to the light receiving element. .., And obtaining distances a, b, c... From the axis of the optical probe to the inner peripheral surface of the hole based on the light receiving position of the light receiving element, and then moving the optical probe to the second measuring position in the probe axial direction. The distances a1, b1, c1,... From the axis of the optical probe to the inner peripheral surface of the optical probe are obtained in the same manner as described above, and the obtained distances a and a1, distances b and b1, and distances c and c1,. If the ratios are different, the axis of the optical probe and the axis of the hole do not match or are parallel The first and second measurement positions are calculated after correcting the deviation of the measurement position from each inclination angle, and determining the inclination angles between the distances a and a1, the distances b and b1, and the distances c and c1,. The hole shape is obtained by obtaining the hole inner diameters at the first and second measurement positions from the center coordinates.

  The reflected light is guided to the imaging lens by a light guide member composed of a mirror or a prism, the measurement light is irradiated to the inner peripheral surface of the hole by a ball lens, or the reflected light is imaged by one imaging lens. May be.

  In the present invention, three or more points on the circumferential surface of the hole serving as the first measurement position are irradiated with measurement light simultaneously or sequentially, and the reflected light from the inner surface of the hole is guided to the imaging lens by the light guide member and used as the light receiving element. The light probe is guided, and distances a, b, c,... From the axis of the optical probe to the inner peripheral surface of the hole are obtained based on the light receiving position of the light receiving element, and the optical probe is moved to the second measuring position in the probe axial direction. In the same manner as described above, distances a1, b1, c1,... From the axis of the optical probe to the inner peripheral surface of the hole are obtained, and the obtained distances a and a1, distances b and b1, and distances c and c1. Are different from each other, it is determined that the axis of the optical probe and the axis of the hole do not match or are not parallel, and the distances a and a1, the distances b and b1, and the distances c and c1. The first and second measurement positions are obtained after each inclination angle is obtained and the deviation of the measurement position is corrected from each inclination angle. By obtaining the hole inner diameter at the first and second measurement positions from the center coordinates to obtain the hole shape, the hole shape can be accurately measured even if the hole to be measured is a tapered hole or the hole axis is inclined. can do.

  Further, as described in claim 2, by guiding the reflected light to the imaging lens by the light guide member made of a mirror or a prism, the structure becomes simple and the accuracy of the assembly structure can be improved.

  Further, as described in claim 3, by irradiating the inner peripheral surface with the measurement light by the ball lens, it is possible to reduce the influence that the reflected light image diameter increases due to the distance from the inner peripheral surface of the hole.

  As described in claim 4, by forming an image of the reflected light with one imaging lens, the structure is simple, the assembly is easy, the accuracy is easily improved, the productivity is improved, and the manufacturing cost is reduced. it can.

It is sectional drawing which shows the 1st Example of this invention. It is explanatory drawing which shows the state which the axis line of the hole and the axis line of the probe corresponded. It is explanatory drawing which shows the state where the axis line of a hole and the axis line of a probe are parallel, but do not correspond. It is explanatory drawing which shows the state in which the axis line of the taper hole and the axis line of the probe corresponded. It is explanatory drawing which shows the state which the axis line of a taper hole and the axis line of a probe are parallel, but do not correspond. It is explanatory drawing which shows the state which the axis line of the hole inclined with respect to the axis line of a probe. It is explanatory drawing which shows the state which the axis line of the taper hole inclined with respect to the axis line of a probe. It is explanatory drawing which shows the measuring method when the axis line of a taper hole inclines with respect to the axis line of a probe. It is explanatory drawing which shows the correction method of the shift | offset | difference of a measurement position. It is explanatory drawing which shows the method of calculating | requiring a taper angle. It is explanatory drawing which shows the case where three points in a 1st measurement position and a 2nd measurement position are measured by the equal distance. It is explanatory drawing which shows the case where 3 points | pieces in a 1st measurement position and a 2nd measurement position are measured by the different distance. It is sectional drawing which shows the 2nd Example of this invention. It is sectional drawing which shows the 3rd Example of this invention.

Next, a first embodiment of the present invention will be described in detail with reference to FIG.
In the figure, reference numeral 1 denotes an optical probe according to the present invention. The optical probe 1 includes a head 2 disposed outside the inner peripheral surface of a molded product and a lens barrel portion 3 that is loosely inserted into the hole.

  The head 2 includes a position detection sensor, a light receiving element 20 such as a CCD element, a relay lens 21 for enlarging, reducing, or equalizing reflected light to enter the light receiving element 20, a light source 22 such as a laser diode or a light emitting diode, a light source A condenser lens 23 that collects the light toward the optical fiber 24, three optical fibers 24 that guide the measurement light into the hole, and the like are provided. In the case of a position detection sensor, the measurement light is sequentially irradiated and received, and in the case of a CCD element, measurement light for three colors can be irradiated and received simultaneously. Note that by changing the focal length ratio of the relay lens 21, the projection magnification can be changed and can be adjusted to the size of the light receiving element 20.

  Three mirrors 30 for reflecting the measuring light toward the inner peripheral surface of the hole are arranged at 120 ° intervals on the periphery of the tip of the lens barrel 3. The tip of each optical fiber 24 faces the slope of the mirror 30. Instead of arranging the mirror 30, the front end surface of the optical fiber 24 may be cut obliquely so that the measurement light is reflected by the cut surface and applied to the inner peripheral surface of the hole. The measurement light may be applied to the hole inner peripheral surface from an oblique direction.

  Further, a mirror 32a as a light guide member 32 facing the imaging lens 31 is attached to the tip of the lens barrel 3, and the reflected light from the inner peripheral surface of the hole is guided to the imaging lens 31. ing. Further, a beam stop 33, an imaging lens 31, a field lens 34, a rod lens 35, or an image conduit are sequentially arranged on the optical axis behind the mirror 32a. The mirror 32a specifically uses a cone mirror, a pyramid mirror, or the like.

  In such a structure, the optical probe 1 is inserted into the hole with the axis of the hole coincided with the axis of the probe in the hole formed in the molded product, and the measurement light emitted from the optical fiber 24 is mirrored. The inner wall surface of the hole is irradiated obliquely to the inner peripheral surface of the hole through 30.

  Irradiation of measurement light is performed simultaneously or sequentially at at least three points at intervals of 120 °. In the case of simultaneous irradiation, three points can be detected simultaneously by causing the CCD element to receive three different colors. If the light cannot be received at the same time as in the position detection sensor, the measurement light is blinked sequentially, or the measurement light is turned on and off by the shutter, and the measurement is performed every three points.

  The measurement light applied to the inner peripheral surface of the hole is reflected, is incident on the mirror 32 a, is reflected, and is guided to the imaging lens 31 through the beam stop 33. Then, the light is received by the light receiving element 20 through the field lens 34, the rod lens 35, the image conduit, and the relay lens 21.

  For example, as shown in FIG. 11, the reflected light received by the light receiving element 20 is measured at distances a, b, and c at the first measurement position.

  Next, the optical probe 1 is moved by a certain distance, and the same measurement as described above is performed at the second measurement position, and distances a1, b1, and c1 are obtained as shown in FIG. At this time, if the distances a, b, c and the distances a1, b1, c1 are the same ratio, the axis of the optical probe 1 coincides with the axis of the hole, as shown in FIGS. Since the axis and the axis of the hole are parallel, the center coordinates of the hole are obtained based on the distances a, b and c of the first measurement position, and the inner diameter of the hole is obtained. When it is known that the axis of the optical probe 1 is coincident with the axis of the hole, or the axis of the optical probe 1 and the axis of the hole are parallel, the hole is measured by one measurement. Can be obtained. 2, 3, and 4, two measurement positions are represented for easy understanding.

Further, after obtaining the center coordinates of the hole based on the distances a1, b1, and c1 of the second measurement positions, the inner diameter of the hole is obtained, and as shown in FIG. 10, based on the first and second inner diameters. seeking determined by the taper angle theta ₂ quadratic holes ^{_{θ 2 = tan -1 {(D}} 2 -D 1) / 2p}, measured parallel holes, tapered holes of the hole-shaped hole.

As shown in FIGS. 5, 6, and 7, the axis of the optical probe 1 and the axis of the tapered hole are parallel but not coincident, or the axis of the tapered or parallel hole and the axis of the probe are inclined. In this case, the ratios of the distances a, b, c of the first measurement positions and the distances a1, b1, c1 of the second measurement positions obtained by moving the optical probe 1 by a certain distance in the probe axis direction are different. As shown in FIG. 8, θ ₁ = tan ⁻¹ {(L ₂ −L ₁ ) / (p−z ₁ + z ₂ )} is obtained from the following equation for the inclination angle θ ₁ for every three points. 5, 6, and 7, two measurement positions are represented for easy understanding.

Then, as shown in FIG. 9, the displacement of the measuring position wherein L ₁ obtained from ^{_{z 2 tanθ 1 - '= L}} 1 - z 1 tanθ 1 and wherein L ^_2' = L _2. In this way, the deviation is corrected, the center coordinates of the hole are obtained, and the inner diameter of the hole is obtained. Then, similarly to the above, seek determined by the taper angle theta ₂ quadratic holes ^{_{θ 2 = tan -1 {(D}} 2 -D 1) / 2p}, measured parallel holes, tapered holes of the hole-shaped hole. In FIG. 9, the holes are greatly inclined for easy understanding.

  FIG. 13 shows a second embodiment of the present invention. The difference from the first embodiment is that the measurement light is irradiated onto the inner wall surface of the hole through the prism 36 and the mirror 32a. Instead of the prism 32b as the light guide member 32, the reflected light is guided to the imaging lens 31, and the measurement light is irradiated to the inner wall surface of the hole through the ball lens 38. The configuration and operational effects are the same as those of the first embodiment, except that the lens 38 is used to increase the light intensity of the measurement light to improve the detection accuracy, and the prism 32b is used to improve the assembly accuracy. Therefore, explanation is omitted. The prism 32b specifically uses a cone prism, a pyramid prism, or the like.

  FIG. 14 shows a third embodiment of the present invention, in which a ball lens combining two hemispherical lenses 39 and a point where measurement light is irradiated on the inner wall surface of the hole through the hemispherical lens 39 is an imaging lens. The first embodiment is the same as the first embodiment except that the number of lenses is reduced by performing irradiation and imaging using a ball lens in which two hemispherical lenses 39 are overlapped. Since it is the same, explanation is omitted.

1 Optical probe 2 Head
20 Photo detector
21 Relay lens
22 Light source
23 condenser lens
24 Optical fiber 3 Tube section
30 mirror
31 Imaging lens
32 Light guide member
32a mirror
32b prism
33 Light aperture
34 Field lens
35 Rod lens (image conduit)
36 prism
38 ball lens
39 Hemispherical lens

Claims (4)

  In a hole shape measuring method for measuring a hole shape by inserting an optical probe into a hole formed in a hole formed in a molded article and irradiating measurement light on the inner peripheral surface of the hole. 3 or more points on the circumferential surface of the hole serving as the measurement position of 1 are irradiated simultaneously or sequentially, and the reflected light from the inner surface of the hole is guided to the imaging lens by the light guide member and guided to the light receiving element, Based on the light receiving position of the light receiving element, the distances a, b, c... From the axis of the optical probe to the inner peripheral surface of the hole are obtained, and the optical probe is moved to the second measurement position in the probe axial direction. Similarly, the distances a1, b1, c1,... From the axis of the optical probe to the inner peripheral surface of the hole are obtained, and the ratios of the obtained distances a and a1, distances b and b1, and distances c and c1. If they are different, the axis of the optical probe and the axis of the hole do not match or are not parallel Then, the respective inclination angles between the distances a and a1, the distances b and b1, and the distances c and c1,... Are obtained, and the center of the first and second measurement positions is corrected by correcting the deviation of the measurement position from each inclination angle. A hole shape measuring method characterized by obtaining hole shapes by obtaining hole inner diameters at first and second measurement positions from coordinates.   The hole shape measuring method according to claim 1, wherein the reflected light is guided to the imaging lens by a light guide member made of a mirror or a prism.   3. The hole shape measuring method according to claim 1, wherein the measurement light is irradiated to the inner peripheral surface of the hole by a ball lens. 4. The hole shape measuring method according to claim 1, wherein the reflected light is imaged by one imaging lens.

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