JPH0585005B2 - - Google Patents

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.

(Prior Art) Many measurement techniques of this type have been proposed in the past.

For example, Utility Model Publication No. 40-16377 or Japanese Patent Application Publication No. 52
-119253 proposes a method for 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 thick materials on the same rotary plate, one set of devices for thin materials placed above and below and two sets of devices for thick materials placed on the left and right are used separately. A measuring device has been proposed.

The above-mentioned rotary type dimension measuring device consists of an annular rotating plate, a device that rotationally drives the rotating plate, three sets of light projecting devices that irradiate the object to be measured with parallel measurement light, a small diameter detection device (for thin materials), and a device that rotates the rotating plate. Equipped with a pair of large diameter detection devices (for thick materials). These light projecting device, small-diameter detection device, and a pair of large-diameter detection devices are attached to a rotating plate, and the small-diameter detection device and large-diameter detection device have an imaging optical system and It has 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 measuring the number of shadows within a group of photoelectric elements arranged in a row. . Although the minimum measurable diameter in this method is possible from one light receiving element, there is a limit to the maximum measurable diameter. In other words, the maximum measurable diameter is "one light-receiving element (resolution) x number of light-receiving elements", so increasing resolution means decreasing accuracy.
There are limits 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 also restrictions such as an increase in the aperture of the imaging lens.

Next, the measuring device for thick materials measures the outer diameter by detecting both ends of the shadow generating area using two photoelectric element groups. With this measuring device made of thick materials, it is physically impossible to set the installation interval between the two sets of photoelectric element groups to 0, and there are also spatial restrictions on the installation of the light projector and imaging lens. Therefore, there is a certain limit to the minimum measurable diameter. Therefore,
In order to continuously measure objects ranging from thin to thick objects, it is necessary to use two or more of the above-mentioned devices. This has led to 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 an increase in cost.

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 capable of continuously measuring thin to thick materials with high accuracy, has a simple structure, and is inexpensive.

(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 includes 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. 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 uses a CCD type image sensor or a MOS type image sensor.

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 behind 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 such that both edge images of the small-diameter object to be measured are incident on the small-diameter detection device. Further, the pair of mirrors are inclined with respect to the optical path of the measurement light, and are arranged so as to face each other on both sides of the measurement light center line behind the half mirror. 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.

Note that the light projecting device, the small-diameter detection device, the pair of large-diameter detection devices, the half mirror, and the pair of mirrors may be attached to one substrate.
In this case, the substrate is supported by a support stand or the like. Generally, the object to be measured is sent in a horizontal position, so the board surface is vertical.
Further, the substrate may be supported rotatably or swingably. 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 a 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 device of this example is
Measuring the outer diameter of high-temperature round steel inline.

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 the measurement light L 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.
The rotating plate 11 includes a light projecting device 21, which will be described later, a small-diameter detection device 31, a pair of large-diameter detection devices 41 and 42,
Half mirror 51 and a pair of mirrors 54, 55
are attached to each. In addition, rotating plate 1
1 is rotationally driven by a rotary plate drive device 14.

The rotating plate drive device 14 includes an electric motor 15, a driving pulley 16, a driven pulley 17, and a toothed belt 18.
It's getting more familiar. The driving pulley 16 is the electric motor 1
The driven pulley 17 is attached to the output shaft of the hub 6, and the driven pulley 17 is attached to the flange 8 of the hub 6. The rotating plate 11 is rotationally driven by the electric motor 15 via this belt transmission mechanism. In this embodiment, the rotation speed of the 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 2
3, mirrors 24 and 25, a cylinder lens 26, a spatial filter (aperture) 27, and a parabolic mirror 28. The collimator lens 23 focuses the coherent light from the semiconductor laser 22,
A cylinder lens 26 is located at that spot. 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 L. light source 22
The light from the parabolic mirror 28 is diffused in a fan shape.
It 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 due to the difficulty of manufacturing the lens. It wasn't practical.

The small diameter detection device 31 is arranged on the side of the optical path of the measurement light L. 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 the imaging surface of the imaging lens 33. A CCD element having a length of 7μ in the arrangement direction is used as a photoelectric element. and,
An optical image of the round steel S is formed on the image sensor 36 by the measurement light L irradiated onto the round steel S by the light projector 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 bent by 90 degrees by the mirror 34.

The pair of large-diameter detection devices 41 and 42 are the measurement light L
They are arranged behind the small-diameter detection device 31 so as to face each other on both sides of the optical path. The configuration of the detection device itself is the same as the small diameter detection device 31, and includes an imaging lens 43, a mirror 44, and an image sensor 46.
It is equipped with

The half mirror 51 has a 45-degree angle with respect to the optical path of the measurement light L.
It is arranged at an angle. The image of the round steel S is reflected by the half mirror 51, and the image of the round steel S with a small diameter is
An image including both edges 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 devices 41 and 42 as a common light beam, the half mirror 51 has a transmittance:reflection ratio of 1:1. rate.

A pair of mirrors 54 and 55 are inclined at 45 degrees with respect to the optical path of the measurement light L, 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 and 55, and the image including one edge of the large diameter round steel S is incident on the large diameter detection devices 41 and 42, respectively.

A primary coil of a rotary transformer 58 is attached to the hub 6, and a secondary coil is attached to the stand 1. Linear image sensor 36, 46
The signals from the display are transmitted to a signal processing device, a display device (none of which are shown), etc. via a rotary transformer 58.

Water cooling cylinders 61 and 6 are provided on the inside and exit sides of the hub 6, respectively.
2 is provided. Cooling water circulates inside these water cooling cylinders 61 and 62, and the rotary transformer 58
Prevents other attached equipment from being overheated by the hot round steel S. An entry guide 64 is attached to the water cooling cylinder 61 on the entry side, and an exit guide 65 is attached to the water cooling cylinder 62 on the exit side.
are placed respectively. An air ring nozzle 67 is attached to the outside of the outlet water cooling cylinder 62. The air ring nozzle 67 blows clean air into the round steel passage in a ring shape to prevent the optical path of the measurement light L from fluctuating due to overheating of the air, and also removes dust floating in the optical path to prevent measurement due to dust. Prevent light 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 71 and 72 are reciprocated by a drive device (not shown) and periodically slide 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 not only when the cross-sectional shape is circular but also 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). Moreover, since the measurement is performed while feeding the round steel S in its longitudinal direction, the diameter is measured while scanning the round steel S in a spiral shape.

In the device 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 large diameter light receiving element group can measure diameters of 35 to 100 mm. In contrast, the device of this embodiment can be expanded to 150 mm or more.
In addition, the measurement error due to the small diameter detection device 31 is ±
20 μm, and the measurement error by the large diameter detection devices 41 and 42 is ±40 μm.

The present invention is not limited to the above embodiments; for example, the half mirror 51 or the pair of mirrors 54 and 55 may be at an angle other than 45 degrees with respect to the measurement light L in view of the installation space. Although the measurement was carried out while rotating the rotary plate 11, the light projecting device 21, the detecting devices 31, 41, 42, etc. may be attached to a fixed base or the like.
Further, although the small diameter detection device 31 and the large diameter detection devices 41 and 42 are L-shaped, they may be straight cylindrical. Furthermore, 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 L so that both edge images of the small diameter object S to be measured are incident on the small diameter detection device 31. ing. The half mirror 51 divides the measurement light L into two. Also, large-diameter detection devices 41 and 4 have a pair of edge images on one side of the large-diameter object S to be measured.
A pair of mirrors 54 and 55 are arranged so as to be inclined with respect to the optical path of the measurement light L so as to be incident on each of the measurement light beams L and to face each other on both sides of the measurement light center line behind the half mirror 51. Therefore,
Small diameter detection device 31 and large diameter detection device 41,
42 can be used depending on the diameter of the object to be measured S, and the outer diameter of the object to be measured S can be measured over a wide range with 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. Furthermore, since measurements are carried out using a single measurement light L that is common to both thin and thick objects, it has become possible to accurately measure the outer diameter or roundness of the object S to be measured.

[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. 1... Stand, 6... Hub, 11... 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
...Half mirror, 54, 55...Mirror, 58
... Rotating transformer, 61, 62 ... Water cooling cylinder, 6
4, 65... Guide, 67... Air ring nozzle, 71, 72... Cleaner, S... Measured object,
L...Measurement light.

Claims (1)

[Claims] 1 Equipped with a light projector that irradiates the object to be measured with parallel measurement light, a small-diameter detection device, and a pair of large-diameter detection devices, and the small-diameter detection device and the large-diameter detection device each detect an image of the measurement object. In an apparatus having an imaging optical system and a linear image sensor,
A detection device for small diameters is placed on the side of the optical path of the measurement light, and a pair of detection devices for large diameters are placed behind the detection device for small diameters so as to face each other on both sides of the optical path of the measurement light. A half mirror is installed at an angle with respect to the optical path of the measurement light so that both edge images of the object to be measured enter the small-diameter detection device, and one side edge image of the large-diameter object enters the small-diameter detection device. a pair of mirrors that are inclined with respect to the optical path of the measurement light so as to be incident on each of the detection devices, and are provided so as to face each other on both sides of the center line of the measurement light behind the half mirror; Body outer diameter measuring device.