JPH01163602A - Rod-shaped body outer diameter measuring device - Google Patents

Abstract

PURPOSE:To accurately measure the external diameter or circularity of the rod-shaped body by providing one light projection device which projects parallel measurement light on the body to be measured, a small-diameter detecting device, a couple of large-diameter detecting device, a half-mirror, and a couple of mirrors. CONSTITUTION:The couple of large-diameter detecting devices 41 and 42 are arranged on both sides of the optical path of the measurement light L behind the small-diameter detecting device 31 opposite each other. The couple of mirrors 54 and 55 slant at 45 deg. to the optical path of the measurement light L and are arranged behind the mirror 51 opposite each other across the center line of the measurement light. The small-diameter detecting device 31 and large- diameter detecting devices 41 and 42 are used selectively according to the diameter of the body S to be measured and the external diameter of the object body S is measured over a wide range by the projection device 21. Further, object bodies from a thin body to a thick body are measured with the one common measurement light beam L, so the external diameter or circularity of the object body S is accurately measured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for measuring the outer diameter of a rod-shaped object, and more particularly to an apparatus for measuring the outer diameter of a rod-shaped object by optically capturing the outline of the object to be measured.

The outer diameter measuring device of the present invention is used to measure the outer diameter of round steel, steel pipes, steel wires, and other materials or shapes.

(Conventional technology) Conventionally, many measurement techniques of this type have been proposed.

For example, Utility Model Publication No. 40-16377 or Unexamined Japanese Patent Publication No. 52
-119253 proposes a method of continuously measuring the diameter of a bar over its entire circumference using a rotating optical system configured by attaching a light source and a detection unit to a rotating plate.

In addition, as a device for measuring thin materials and large materials on the same rotating plate, one set of devices for thin materials placed on the vehicle and two sets of devices for large materials placed on the left and right are used separately for rotary dimension measurement. device has been proposed.

The above-mentioned rotary type dimension measuring device includes an annular rotating plate, a device that rotationally drives the rotating plate, and a device that irradiates parallel measurement light onto the object to be measured.
It is equipped with a pair of light projectors, a small-diameter detection device (for thin materials), and a pair of large-diameter detection devices (for large materials). These light projecting device, small diameter detection device, and a pair of large diameter detection devices are attached to a rotary plate and are connected to each other. It has an optical system and a linear image sensor.

Then, the rotating plate is rotated so that the axis of the measured object coincides with the center of the rotating plate, and while feeding the measured object, the measuring light is projected onto the measured object by the light projector, and the measuring light is emitted by the small diameter detection device. The outer diameter of the object to be measured is measured by detecting both edges of the object to be measured having a small diameter and by detecting one edge of the object to be measured having a large diameter using a pair of detection devices for large diameters.

(Problems to be Solved by the Invention) In the conventional device described above, the device for measuring thin materials measures the outer diameter by counting the number of shadows within a group of photoelectric elements arranged in a line. Although the minimum measurable diameter in this method is possible from one light receiving element, there is a limit to the maximum measurable diameter. That is, the maximum measurable diameter is ``resolution for one light-receiving element'' x number of light-receiving elements, so increasing the resolution means decreasing accuracy, so there is a limit in terms of accuracy. Furthermore, when the number of light receiving elements is increased, the amount of information increases, so it takes a long time to process the detection signal. Furthermore, there are other restrictions such as an increase in the aperture of the imaging lens.

Next, the measuring device for large materials measures the outside diameter by detecting both ends of the shadow generating area using two sets of photoelectric elements. With this measuring device for large materials, it is physically impossible to set the installation interval between the two photoelectric element groups to O, and there are spatial restrictions on the installation of the light projector and imaging lens. , there is a certain limit to the minimum measurable diameter. Therefore, in order to continuously measure objects ranging from small objects to large objects, it is necessary to use two or more of the above-mentioned devices. However, there were other problems such as a space problem, a difference in luminous flux because the two sets of light projecting parts of both devices are independent, which causes errors, and increased costs.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an apparatus for measuring the outer diameter of a rod-shaped body, which is simple in structure and inexpensive, and is capable of continuously measuring both thin and large materials with high accuracy.

(Means for Solving the Problems) The rod-shaped body outer diameter measuring device of the present invention includes a set of light projecting devices that irradiate parallel measurement light onto an object to be measured, a small diameter detection device, and a pair of large diameter detection devices. It is equipped with a detection device, a half mirror, and a pair of mirrors.

The light projection device includes a light source and a projection optical system. A semiconductor laser, a gas laser, or an incandescent lamp such as a halogen lamp is used as a light source. The projection optical system consists of a collimator lens, a parabolic mirror, etc. in order to produce a wide range of parallel light, and can continuously measure objects from small diameters to large diameters using a set of light projection devices.

The small-diameter detection device and the large-diameter detection device each have an imaging optical system and a linear image sensor that detect an image of the object to be measured. A linear image sensor consists of a group of photoelectric elements arranged in a straight line, and a CGD type image sensor or an MO5 type image sensor is used.

The small diameter detection device is placed on the side of the optical path of the measurement light. In addition, the pair of large-diameter detection devices are placed opposite to each other on both sides of the optical path of the measurement light, and are placed further back than the small-diameter detection device, that is, further away from the object to be measured along the traveling direction of the measurement light. has been done.

The half mirror is arranged so as to be inclined with respect to the optical path of the measurement light. The inclination angle is an angle at which both edge images of the small-diameter object to be measured are incident on the small-diameter detection device. In addition, the pair of mirrors is inclined with respect to the optical path of the measurement light,
They are arranged behind the half mirror so as to face each other on both sides of the center line of the measurement light. The inclination angle of the mirror is such that one side edge image of the large-diameter object to be measured is incident on each of the paired large-diameter detection devices.

In addition, the ten-ki projector, the small-diameter detection device, a pair of large-diameter detection devices, a half mirror, and a pair of mirrors may be mounted on one substrate. In this case, the substrate may be It is supported on a stand, etc. Generally, the object to be measured is sent in a horizontal position, so the board is in a position with the board surface vertical.Also, the board is supported so that it can rotate or swing. In this case, a combination of an ordinary belt transmission mechanism, chain transmission mechanism, gear transmission mechanism, etc., and an electric motor, a fluid pressure cylinder, etc. is used as the rotation or swing driving device for the substrate.

(Function) In the case of a small-diameter measured object, the image of the measured object is reflected by a half mirror and formed on the imaging plane of the linear image sensor of the small-diameter detection device. The diameter of the object to be measured is detected as the length of the shadow part of the image of the object to be measured.

Furthermore, in the case of a large-diameter object to be measured, the distance between the reference points of the linear image sensors of both large-diameter detection devices is determined in advance. The image of the object to be measured passes through the half mirror, is reflected by each of the pair of rear mirrors, and is imaged on the imaging plane of the linear image sensor of each large-diameter detection device. The image of the object to be measured formed on the linear image sensor is an image of a part of the object to be measured, including an edge on one side. The diameter is determined by the distance between the reference points of the linear image sensor and the position of the image of the edge of the object relative to the linear image sensor. Note that when the diameter of the object to be measured is larger than the width of the half mirror, the image of the object to be measured is directly incident on the mirror without passing through the half mirror.

(Embodiment) FIGS. 1 and 2 show an embodiment of the outer diameter measuring device of the present invention, in which FIG. 1 is a longitudinal sectional view and FIG. 2 is a front view. The apparatus of this embodiment measures the outer diameter of high-temperature round steel in-line.

As shown in FIG. 1, a cylindrical hub 6 is rotatably supported by a stand 1 via a bearing 3 in a horizontal position. A transmission window 7 through which measurement light passes is provided near the tip of the hub 6.

An annular rotary plate 11 is fixed to a flange 8 provided near the tip of the hub 6 with bolts. A light projecting device 21, a small-diameter detection device 31, a pair of large-diameter detection devices 4, 42, a half mirror 51, and a pair of mirrors 54 and 55 are attached to the rotary plate 11, respectively.

Further, the rotary plate 11 is rotationally driven by a rotary plate driving device 14.

The rotary plate drive device 14 includes an electric motor 15 and a driving pulley 16.
, a driven pulley 17 and a toothed belt 18. The driving pulley 16 is mounted on the output shaft of the electric motor 15, and the driven pulley 17 is mounted on the flange 8 of the hub 6.
I'm being kicked. The rotating plate 11 is rotationally driven by the electric motor 15 via this belt transmission mechanism. In this example, the rotation speed of rotary plate 11 is 60 rpm.

The light projection device 21 includes a semiconductor laser 22 as a light source, as shown in FIGS. 3 and 4. The projection optical system of the light projector 21 includes a collimator lens 23 and mirrors 24 and 25.
, a cylinder lens 26, a spatial filter (aperture) 27, and a parabolic mirror 28. The collimator lens 23 collects the coherent light from the semiconductor laser 22, and the cylinder lens 26 is located at the spot point of the coherent light. The light diffused in a fan shape from the cylinder lens 26 is reflected by the parabolic mirror 26 installed at the focal length position to generate parallel measurement light. Since the light from the light source 22 is diffused in a fan shape, the parabolic mirror 28 has a horizontally elongated shape. Since the light from the light source 22 is coherent light, noise is generated due to diffraction and interference phenomena, but the spatial filter (aperture) 27 removes this noise. In addition, since conventional devices generate parallel light using a collimator lens, a large-diameter lens is required to generate a wide range of parallel light, which is difficult both physically and in terms of lens manufacturing. It wasn't practical.

The small diameter detection device 31 is arranged on the side of the optical path of the measurement light. The small-diameter detection device 31 includes an imaging lens 33 and an image sensor 36 made up of a large number of photoelectric elements arranged in a line on its imaging plane -F. A CCD element having a length of 7 microns in the arrangement direction is used as a photoelectric element. Then, an optical image of the round steel S is formed on the image sensor 36 by the measurement light irradiated onto the round steel S by the light projection device 21 . As a result, the outer diameter of the round steel S is measured from a signal corresponding to the size of the optical image obtained by the image sensor 36. Note that due to the installation space of the small-diameter detection device 31, the optical path of the imaging system is
It's bent a lot.

The pair of large-diameter detection devices 4] and 42 are arranged behind the small-diameter detection device 31 so as to face each other on both sides of the optical path of the measurement light. The configuration of the detection device itself is the same as that of the small diameter detection device 31, and includes an imaging lens 43, a mirror 44, and an image sensor 46.

The half mirror 51 is arranged so as to be inclined at 45 degrees with respect to the optical path of the measurement light. The image of the round steel S is reflected by the half mirror 51, and the image including both edges of the small diameter round steel S is incident on the small diameter detection device 31. In order to irradiate the small-diameter round steel S and the large-diameter round steel S to the small-diameter detection device 31 and the large-diameter detection device 4 and 42 as a common light beam, the half mirror 51 has a transmittance of 11 and a reflectance of 11. It becomes.

A pair of mirrors 54 and 55 are inclined at 45 degrees with respect to the optical path of the measurement light, and are arranged behind the half mirror 51 so as to face each other on both sides of the measurement light center line. The image of the round steel S is reflected by mirrors 54, 55, and the images including one edge of the large diameter round steel S are incident on each of the large diameter detection devices 41, 42.

A primary coil of a rotary transformer 58 is attached to the hub 6, and a secondary coil is attached to the stand 1.

Signals from the linear image sensors 36 and 46 are passed through a rotary transformer 58 to a signal processing device and a display device (I1'
(not shown), etc.

Water cooling units n6+ and 62 are provided on the inside and exit sides of the hub 6, respectively. Cooling water circulates inside these water cooling cylinders fil, ti2, and prevents the rotary transformer 58 and other attached equipment from being overheated by the hot round steel S. The entrance guide 64 is attached to the water cooling cylinder 61 on the entrance side, and the water cooling cylinder 62 on the exit side
Output side guides 65 are arranged respectively. A nearing nozzle 67 is attached to the outside of the outlet water cooling cylinder 62. The nearing nozzle 67 blows clean air into the round steel passage in a ring shape to prevent fluctuations in the optical path of the measurement light due to overheating of the air, and also removes dust floating in the optical path and prevents the measurement light from being caused by clumps. prevent scattering.

A light transmitting side cleaner 71 and a light receiving side cleaner 72 are provided in the transmission window 7 at the tip of the hub 6 . These cleaners 7
1.72 is reciprocated by a drive device (not shown) and periodically slides on the transparent window surface to wipe it clean.

Since the measurement is performed while rotating the rotary plate 11, the outer diameter is measured from multiple directions. Therefore, the outer diameter can be measured even if the cross-sectional shape is not only circular but polygonal. For example, for a regular n-gon (n: an even number of 4 or more), the maximum value (local maximum value) indicates the outer diameter (maximum length diagonal line). Also, measure while feeding the round steel S in the longitudinal direction. Therefore, the diameter is measured while scanning the round steel S in a spiral manner.

In the apparatus of this example, 5000 light receiving element groups were arranged and the lens magnification was 0.7. The small-diameter detection device 31 can measure diameters up to 35 mm, and larger diameters are measured by the large-diameter detection devices 41 and 42. In addition, in the conventional fixed type device, assuming that the light receiving element group and the lens magnification are the same as those of this embodiment, the diameter of the large diameter light receiving element group can be measured from 35 to 00 mm.

In contrast, the device of this embodiment can be expanded to 150 mm or more. Further, the measurement error by the small diameter detection device 31 is ±20IJIII, and the large diameter detection device 4],
The measurement error due to 42 is ±40 μm.

The present invention is not limited to the above-mentioned embodiments, but includes, for example, a half mirror 51 or a pair of mirrors 54.5.
5 may be at an angle other than 45 degrees with respect to the measurement light in view of the installation space. The measurement was carried out while rotating the rotating plate 11, but the light projecting device 2], the detecting devices 31, 41 .
42 or the like may be attached to a fixed base or the like. Furthermore, the small-diameter detection device 31 and the large-diameter detection device 41, 42 may be L-shaped, or may be shaped like a stiffener. Alternatively, a wireless system may be used as the transmission device instead of the rotary transformer 58.

(Effects of the Invention) In the apparatus of the present invention, the half mirror 51 is arranged so as to be inclined with respect to the optical path of the measurement light so that both edge images of the small-diameter object S to be measured are incident on the small-diameter detection device 31. There is. The half mirror 51 divides the measurement light into seven parts. Further, it is inclined with respect to the optical path of the measurement light so that the edge image of one side of the large-diameter object S is incident on each of the pair of large-diameter detection devices 4 and 42, and is located behind the half mirror 51. A pair of mirrors 54 and 55 are arranged facing each other on both sides of the measurement light center line. Therefore, the detection device 31 for small diameter and the detection device 41, 42 for large diameter are connected to the object to be measured S.
The outer diameter of the object to be measured S can be measured over a wide range using one set of light projecting devices 21. As a result, it is not necessary to provide several sets of detection devices, and the space for installing the devices can be narrow.

In addition, since measurements are carried out using one common measurement light for everything from small objects to large objects, it has become possible to measure the outer diameter or roundness of the object S to be measured well.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, in which a vertical cross-sectional view of an outer diameter measuring device, FIG. 2 is a front view of the device shown in FIG. 1, and FIG. 3 is a plan view of a light projecting device. FIG. 4 is a side view of the light projecting device shown in FIG. 3. DESCRIPTION OF SYMBOLS 1... Stand, 6... Hub 1.1]... Rotating plate, 14... Rotation drive device, 21... Light projecting device, 22
... light source, 26 ... cylinder lens, 27 ... aperture, 28 ... parabolic mirror, 31 ... small diameter detection device,
36...Image sensor, 41.42...Large diameter detection device, 46...Image sensor, 51...ノ\-
Fumira, 54, 55...Mirror, 58...Rotating transformer, 61.62...Water cooling cylinder, 64.65...
Guide, 67... Nearing nozzle, 71.72...
・Cleaner, S...Object to be measured, L...Measuring light.

Claims (1)

[Claims] Equipped with a light projection device that irradiates the object to be measured with parallel measurement light, a small-diameter detection device, and a pair of large-diameter detection devices, each of which detects an image of the object to be measured. In an apparatus having an imaging optical system and a linear image sensor, a small-diameter detection device is arranged on the side of the optical path of the measurement light, and a pair of large-diameter detection devices are arranged opposite to each other on both sides of the measurement light optical path. A half mirror is placed behind the small-diameter detection device and is tilted with respect to the optical path of the measurement light so that both edge images of the small-diameter object are incident on the small-diameter detection device. A pair of mirrors that are inclined with respect to the optical path of the measurement light are opposed on both sides of the measurement light center line behind the half mirror so that an edge image of one side of the object to be measured is incident on each of the pair of large-diameter detection devices. A device for measuring the outer diameter of a rod-shaped body, characterized in that it is provided as follows.