JPH05118828A - Spiral material measuring apparatus - Google Patents

Abstract

PURPOSE:To make it possible to measure the straightness for even a spiral shaped material, which is assembled in a very deep part without destruction by inserting a target guide into the spiral-shaped material, photographing the image of a target, and operating the position of the target. CONSTITUTION:A material to be measured (slow-wave circuit part) 2 is mounted on an operating mechanism 12, and a target guide 23 is inserted into a spiral. Then, the central position of the target imparts the coordinates of the axis in the cross section of the spiral. The circuit part 2 is slid to the side of a telescope camera 2B on the light axis of the camera. Then, the target traces the axis of the inner diameter of the spiral. The sliding position is read with a length measuring mechanism 13 as a coordinate (z). The displacement of the target, which is photographed with the camera 28, is read as the coordinates X and Y. Then, the shape of the axis of the inner diameter of the spiral can be grasped as the three-dimensional coordinates. The deviation of the straightness of the axis is expressed in accordance with JISBO621. After the scanning along the entire length of the axis of the 4 inner diameter of the spiral is finished, the inclination of the coordinate of the (z) axis is corrected. The diameters of the minimum circumscribed circles at all measuring points projected on the xy plane are computed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral shape measuring device for measuring the straightness and pitch of a spiral.

[0002]

2. Description of the Related Art The straightness and pitch of a spiral must be measured as measurement items for a spiral-shaped object to be measured.

As a device for measuring the straightness of a helix, application of a method for measuring the bend of a pipe can be considered. That is,
For example, Japanese Patent Laid-Open No. 60-253910 discloses a method of scanning an accelerometer along the inside and outside of a tube wall and converting the acceleration amount into a displacement amount. Also, for example, the actual exploitation 5
Japanese Patent Publication No. 9-72607 discloses a method of passing a tubular gauge through a pipe to be measured.

[0004] However, these methods use a very elongated tubular body incorporated inside a structure smaller than an accelerometer or a tubular gauge, such as a helix incorporated in a traveling wave tube. It is not suitable for measuring straightness with respect to the inner diameter axis.

If the inner diameter is relatively large, it is conceivable to collimate the target with an alignment telescope to convert the straightness and measure the straightness. However, when this measurement method is applied to the straightness measurement of the above-mentioned spiral, it is necessary to manufacture a minute target, attach the target to an extremely long and thin inner diameter axis line, move the target, and It is difficult to illuminate.

The structure of the main part of the traveling wave tube described above is shown in FIG. This traveling wave tube is composed of an electron gun 1, a slow wave circuit unit 2 and a collector 3. In the slow wave circuit unit 2 of these, as shown in FIG.
A helix 4 is incorporated into the cladding 5 along with a plurality of supporting dielectrics.

The straightness of the inner diameter axis of the helix 4 is an important geometrical characteristic for ensuring the passage path of the electron beam that travels straight, but up to now, a proper method for nondestructively inspecting and measuring has been proposed. There wasn't.

For example, when the straightness is to be read based on the X-ray transmission image of the helix 4, the shadow image of a structure such as a ball piece or a magnet arranged outside the cladding tube 5 overlaps with the X-ray image. However, sufficient resolution cannot be obtained.

On the other hand, as another method, as shown in FIG. 12, an extremely elongated stylus bar 6 is inserted into the spiral 4,
A method of calculating the straightness from the diagram after drawing the axial cross-sectional contour shape of the inner surface of the helix 4 on the diagram for the four orthogonal wall surfaces using a shape measuring machine was also considered. But with this method,
Contact interference between the inner wall of the spiral 4 and the side back surface of the stylus bar 6 is likely to occur and the rigidity of the stylus bar 6 is insufficient, and this method is not suitable for three-dimensional measurement of the straightness of the inner diameter axis.

In addition, incorporating a strain gauge into the tip of the stylus bar 6 or attaching an electromagnetic induction coil or other ultra-compact high-sensitivity sensor is not a problem, but it is not only difficult to manufacture, but also a measurement is required. I can't find anything that is stable and reliable in terms of time, environment, temperature and electromagnetic fields. After all, although there have been demands for nondestructive measurement, various conventional methods cannot be put to practical use.

Further, the slow wave circuit unit 2 is welded to the electron gun 1 and the collector 3 and vacuum-sealed. Therefore, there is a need for a measuring method that can guarantee the passage of the electron beam regardless of the effect of residual stress generated by welding, but such a method has not been available. Even when the result of the characteristic failure is obtained in the electrical characteristic test performed at the end of the assembly, it is extremely difficult to investigate the cause and take measures for eliminating the failure.

[0012]

As described above, when the object to be measured such as the spiral 4 is surrounded by a structure having a relatively large mass such as a ball piece or a magnet and is located deep inside the narrow space, To measure the straightness of the inner diameter axis, X
Sufficient resolution cannot be obtained from the line image. Also, there is no applicable stylus bar, and it is not possible to use a contour measuring machine.

Further, even if the resin is impregnated and solidified and then cut, and the appearance of the cross-sectional shape is measured, not only the condition for measuring the straightness of the three-dimensional shape is not satisfied, but also when such a destructive inspection is performed. In some cases, helices that are inspected directly cannot be products, and the straightness of individual products remains unknown. Even if these measuring methods are adopted, a long time is required for the measurement. Therefore, it is required to perform nondestructive and automatic three-dimensional measurement of the shape of the narrow inner diameter of an elongated cylindrical object which is incorporated in the deep portion even if it is narrow.

If the object to be measured has a spiral shape, there are almost the same problems in measuring the pitch of the spiral as in measuring the straightness of the spiral. That is, although the pitch of the spiral 4 of the traveling wave tube is relatively easy to measure with a single spiral, it is non-destructive in a state after the slow wave circuit part is assembled after being assembled in the elongated covering tube 5. There was no proper method to inspect and measure.

For example, in order to read the pitch of the helix 4 from the X-ray transmission image, the shadow images of structures such as ball pieces and magnets arranged outside the cladding tube 5 overlap the X-ray image, and the resolution is sufficient. Can't get

On the other hand, as another method, as shown in FIG. 12, an extremely elongated stylus bar 6 is inserted into the spiral 4,
An indirect measurement method has also been considered in which the axial cross-sectional contour shape of the inner surface of the spiral 4 is drawn using a shape measuring machine and then the pitch is read from the diagram. However, in this method, contact interference between the inner wall of the helix 4 and the side surface of the stylus bar 6 is likely to occur, and the rigidity of the stylus bar 6 is insufficient, so sufficient measurement cannot be performed.

In addition, it is possible to incorporate a strain gauge at the tip of the stylus bar 6 or to attach an electromagnetic induction coil or other ultra-compact high-sensitivity sensor. I can't find anything that is stable and reliable in terms of time, environment, temperature and electromagnetic fields. After all, although there have been demands for nondestructive measurement, various conventional methods cannot be put to practical use.

Further, the method of measuring the straightness of the helix and the method of measuring the pitch of the helix are different from each other. Therefore, to measure simultaneously with one device, they simply shared the pedestal of the two devices.

The object of the present invention is to enable non-destructive and automatic three-dimensional measurement of the inner diameter axis of a narrow object, even if it is a spiral object to be measured which is incorporated in the deep part,
By automatically detecting the contour and position of the helix, it is sufficiently stable against temperature and electromagnetic disturbances during measurement, and the straightness or pitch of the helix can be measured with high resolution. Another object of the present invention is to provide an inexpensive spiral shape measuring device that can easily switch between these measurement items and perform measurement.

[0020]

In order to achieve the above object, the present invention provides a target guide which holds a target illuminated on a virtual axis of an object to be measured having a spiral shape and is inserted into the object to be measured. An image guide arranged in parallel with the target guide and inserted into the object to be measured, a measurement item switching means for switching the target guide and the image guide to be inserted into the object to be measured according to the measurement item, and the target guide A target guide image pickup means for picking up an image, an image guide image pickup means for picking up an image transmitted by the image guide, the object to be measured, the target guide and the image guide in the object to be measured. Scanning means for moving on the axis, display means for displaying the output of the target guide imaging means, and the target Calculating means for calculating the position of the coil, output means for outputting the straightness of the spiral from the calculation result of this calculating means, and position for each pitch in the object to be measured from the image data obtained by the image pickup of the image guide image pickup means. And a length measuring means for determining the pitch of the helix from the moving length of the scanning means based on the position for each pitch, and a spiral shape measuring device.

[0021]

In this way, according to the present invention, the target guide is inserted into the object to be measured having a spiral shape, the target guide is imaged, the target guide is moved in the object to be measured, and the output of the target guide imaging means is output. Is displayed, the position of the target is calculated, and the straightness of the spiral is measured by outputting the calculation result.

Then, the image guide is inserted into the object to be measured, the image transmitted by the image guide is picked up, the position for each pitch in the object to be measured is detected from the image data obtained by this image pickup, and this position is set to this position. The pitch of the object to be measured can be found from the moving length.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The same parts as those described in the section of the conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows an embodiment of the present invention. Reference numeral 10 in the drawing is a spiral shape measuring device (hereinafter referred to as a measuring device). This measuring device 10 is, for example, a helix 4 incorporated in a slow wave circuit unit 2 of a traveling wave tube (TWT).
It is applied to the straightness measurement and pitch measurement of the inner diameter axis.

Reference numeral 11 in FIG. 1 denotes a slide table. The slide table 11 is movably supported by a guide rail (not shown), and a scanning mechanism 12 as a scanning means is provided on the slide table 11. Is provided. The scanning mechanism 12 is integrally provided with a length measuring mechanism 13, which is a length measuring means including a length measuring scale and a length measuring head, and measures the position (Z coordinate) of the slide table 11.

Further, the slide table 11 is adapted to move on the guide rails by driving the stepping motor 14 constituting the scanning mechanism 12. The stepping motor 14 is automatically controlled by the servo drive device 15. The moving distance read by the length measuring mechanism 13 is sent to the output device 17 for outputting the helix pitch via the display device 16.

The slide table 11 has a pair of Vs.
Supports 18a and 18b are provided, one V support 18a is mounted on an XY stage, and the other V support 18b is a Z stage (both stages not shown).
It is installed in.

Further, the V supports 18a and 18b are provided with the slow wave circuit section 2 as shown in FIG. 2, and only one side is mounted, and the pole piece 19 of the slow wave circuit section 2 is screwed. It is pressed against the V support 18a by a clamp bar 20 of the type.

On one side of the slide table 12 shown in FIG. 1, a pair of holders 21a on the XY stage 21,
A measurement item switching mechanism 22 which is a measurement item switching means provided with 21b is provided. The holders 21a, 2
A target guide 23 and an image guide 24 are arranged in parallel on 1b. The position of the XY stage 21 is detected by the sensor 21c. The measurement item switching mechanism 22 is controlled by the control unit 45.

FIG. 3 shows the structure of the target guide 23. The target guide 23 has a thin tube 25, a light guide 26 and a target 27. The thin tube 25 is made of a non-magnetic material, and its outer diameter is set smaller than the outer diameter of the spiral 4. The thin-walled tube 25 has flexibility and bends to the extent that it exceeds the measurement range.

The light guide 26 is made of an organic plastic optical fiber and is inserted into the thin tube 25. The target 27 is fitted in the tip of the thin tube 25, and the tip of the light guide 26 is inserted in the center thereof.

That is, the target guide 23 covers the light guide 26 and the target 27 with the thin-walled tube 25 to protect both members 26, 27. Further, the target guide 23 is smoothly inserted into the spiral 4. The target guide 23 is the target 2
7 functions as a target holder that maintains the coaxiality with the inner diameter of the helix 4 and also serves as a guide for scanning the target 27 on the axis to be measured.

As shown in FIG. 1, the target guide 23 is held parallel to the slide direction of the slide base 12 by a holder 21a, and the target 27 is a target guide image pickup means provided on the other side of the slide base 12. It is directed to the optical axis of the telephoto camera 28.

At the opposite end of the target guide 23, a light guide 26 is led out, and the light guide 26 is connected to a light source device 29 of a halogen lamp via an adapter. Then, the light guide 26 illuminates the target 27 with backlight.

The above-mentioned telephoto camera 28 is arranged at a fixed distance from the target 27 (when the total length of the object to be measured> the total length of the object to be measured + α in the case of the shortest focal length of the telescopic camera), the telescopic camera 28 and the target are separated. The distance from 27 is
It is set to be slightly larger than the entire length of the slow wave circuit unit 2.

The optical axis of the telephoto camera 28 is the slide base 1.
The telescopic camera 28 is always focused so as to collimate the target 27 and the inner diameter axis of the helix 4 is aligned with the optical axis of the telescopic camera 28. ..

The telephoto camera 28 is attached to a YZ stage (not shown) and is aligned by this YZ stage. Further, the telephoto camera 28 is a monitor TV as a display unit via an image processing device 30 as a calculation unit.
31 and a printer 32 which is an output means.

On the other hand, in the fiber switching table 21,
An image guide 24 that constitutes a pitch measuring unit together with the target guide 23 is provided. The image guide 24 is, as shown in FIG.
5 and a branching device 36.

The image guide body 35 is shown in FIG.
As shown in (A) and (B), the objective lens 37 is attached to the tip.
Are arranged at eccentric positions, and thousands of optical fiber bundles 38 are optically connected to the objective lens 37. In addition, the objective lens 37 and the optical fiber bundle 3
8 are provided with several tens of optical fiber bundles 39 for light illumination.

The objective lens 37 and the optical fiber bundle 38 are integrally formed by the covering tube 40.
In this case, the outer diameter of the image guide body 35 is smaller than the inner diameter φ0.8 of the spiral 4 and is formed to φ0.75.

The branching device 36 includes the optical fiber bundles 38 and 3
The optical fiber bundle 38 is guided to the rear part of the branching device 36, and the other optical fiber bundle 39 is guided to the flexible tube 41. By guiding the optical fiber bundle 38 to the rear part of the branching device 36, the imaging plane 42 of the objective lens 37 is formed at the rear part of the branching device 36. The flexible tube 41
1 is connected to a light source device 29 together with the light guide 26 of the target guide 23, as shown in FIG.

A television camera (to be referred to as a TV camera hereinafter) serving as an image guide image pickup means through a 100 × microscope objective lens 44 at a position facing the image forming plane 42 of the branching device 36 constituting the image guide 24. Called)
43 are arranged. The image signal output from the TV camera 43 is sent to the image processing device 30.

As shown in FIG. 8, the image processing apparatus 30 provides windows W1 and W2 adjacent to each other in the axial direction of the spiral 4 on the sent image data, and the gray level in these windows W1 and W2. When match
It has a function of detecting an intermediate position between these windows W1 and W2 as a peak density level position of the spiral 4.
The image data obtained by the TV camera 43 or the telephoto camera 28 is sent to the monitor TV 31 to be visualized.

Reference numeral 45 denotes a control unit, which is the image processing apparatus 3 described above.
It controls the threshold value of the image brightness of 0, the window control, and the calculation of the measurement result. Further, the scanning mechanism 12 is automatically controlled to control the light amount of the light source device 29 connected to the target guide 23 and the image guide 24. Further, it receives an operation signal from the operation panel 46, controls the output device 47 for outputting the straightness, and controls the position of the fiber switching table 21.

To explain the operation of the spiral shape measuring apparatus 10 thus constructed, the measuring apparatus 10 will be described below.
(1) The straightness of the axis of the spiral can be measured, (2) the eccentricity of the inner diameter axis of the spiral and the circumferential runout of the measured object to be assembled coaxially with the inner diameter axis of the spiral, and (3) the spiral pitch measurement. Switching of these measurement items (1) to (3) is possible by switching the position of the measurement item switching mechanism 22. Hereinafter, each measurement item will be described. First, the straightness measurement and the concentricity and circumferential runout measurement will be described.

The measurement item switching mechanism 22 controls switching of the position of the fiber switching table 21 so that the target guide 23 faces the object to be measured (helix 4) supported on the slide table 11.

A telephoto camera 28 is provided at one end of the scanning mechanism 12.
Are placed. This telephoto camera 28 has its optical axis oriented parallel to the sliding direction of the slide table 11 and collimates the target 27 provided at the tip of the target guide 23 through a measured object (helix 4) from a predetermined distance. Is adjusted to

When the total length of the object to be measured (helix 4) is larger than the shortest focusing distance of the telephoto camera 28, the distance between the telephoto camera 28 and the target 27 is the object to be measured (helix 4).
Is set to be slightly larger than the total length of.

The slow wave circuit section 2 which is the object to be measured is the scanning mechanism 1.
2 is mounted, the axis of the helix 4 is aligned with the optical axis of the telephoto camera 28, and when the target guide 23 is inserted into the helix 4, the center position of the target 27 is the helix 4
Gives the axis coordinates in the cross section of.

Then, the slow-wave circuit section 2 mounted on the scanning mechanism 12 is moved along the optical axis of the telephoto camera 28.
When slid to the side of, the target 27 traces the inner diameter axis of the helix 4. While reading this slide position as the z coordinate on the length measurement scale of the length measurement mechanism 13, the displacement of the target 27 imaged by the telephoto camera 28 is xy.
If read as coordinates, the shape of the inner diameter axis of the object to be measured (helix 4) can be grasped in three-dimensional coordinates.

The straightness deviation of the axis is represented by "the diameter of the geometric cylinder having the smallest diameter including the axis" according to JIS B 0621 "Definition and display of geometric deviation". When the linear direction of the geometrical cylinder axis does not coincide with the direction of the optical axis, the z coordinate axis needs to be tilt-corrected to calculate the minimum geometrical cylinder diameter.

On the other hand, when there is an axial straightness deviation in the inner diameter of the object to be measured, the visual field in the peripheral portion of the target 27 is obstructed by the inner wall of the object to be measured. Therefore, in order to read the center coordinates of the target 27,
The diameter d of the central portion of the target 27, the inner diameter D of the object to be measured, and the straightness deviation δ of the measurable axis line have the following relationship. D = 2d + δ (1)

It is difficult to make the inner diameter axis of the object to be measured perfectly aligned with the optical axis direction of the telephoto camera 28, which is a time loss. Therefore, it is practical for the inclination of some axes to be calculated by the inclination correction calculation of the z coordinate axis.
And efficient.

When the axis is inclined, the periphery of the target 27 is blocked by the inner wall of the object to be measured,
On the right side of the equation (1), a term of a field-of-view shielding amount ε corresponding to a diameter corresponding to L tan θ where L is the total length of the object to be measured and θ is the angle of inclination of the axis is added. Further, since the target 27 is smoothly inserted, the minimum necessary clearance c between the inner diameter of the object to be measured and the outer diameter of the target guide 23 is added as an error factor in setting the target 27, and is eventually expressed by the following equation. .. D = 2d + c + δ + ε (2)

From the above equation (2), if the diameter d of the center circle of the target 27 is applied under the following conditions, the transmitted light image of the center circle of the target 27 is not lost, and the position of the center of gravity thereof is obtained by image processing, and then measured. It can be coordinates on the power axis. Then, in order to avoid the influence of the reflected light on the inner wall surface of the object to be measured, it is preferable that d is as small as possible so as not to disturb the image input. d ≦ (D−c−δ−ε) / 2 (3) In other words, the measurable range of the straightness deviation δ is expressed by the following equation. δ ≦ D-2d-c-ε (4)

In order to automatically measure the straightness under the conditions described above, first, the slide table 11 of the scanning mechanism 12 is moved until the target guide 23 penetrates the length of the axis of the object to be measured (helix 4). To slide. After that, the slide table 11 scans continuously or at a required pitch in a direction in which the target guide 23 separates from the object to be measured (spiral 4).

On the other hand, the z coordinate is the length measuring mechanism 1.
3 and at the same time, the xy coordinates of the barycentric position of the transmitted and illuminated target image are read by the image calculation from the telephoto camera 28.

After the scanning over the entire length of the inner diameter axis of the object to be measured (spiral 4) is completed, the tilt correction of the z coordinate axis is performed, and as shown in FIG. 6, the minimum of all the measurement points projected on the xy plane is obtained. The circumscribed circle diameter is calculated. The process until the axis line is printed out as a straightness deviation is automatically controlled by the control unit 45.

The target center circle image is imaged from a fixed position by the telephoto camera 28 under constant back light illumination, but nevertheless, the amount of light incident on the telephoto camera 28 is "eclipse". "It occurs and it gets dark. Therefore, the threshold value or the light source level is automatically adjusted so that the image is input with a fixed number of pixels.

Further, practically, if the coordinates of both ends of the measured axis line are connected to form the z-axis and an approximate correction is performed, the inclination correction of the z-coordinate axis is sufficient. If the axis of the inner diameter of the object to be measured is sufficiently aligned with the optical axis of the telephoto camera 28 in advance, the tilt correction of the z coordinate axis can be omitted.

It is possible to variously select the output form of the measurement result. That is, it is possible to display not only the straightness deviation value but also the required number of axis line coordinate values and their diagrams, and make a hard copy of these.

On the other hand, the object to be measured is released while the inserted target 27 is collimated by the telephoto camera 28 and is rotatably supported on the two V supports 18a and 18b. 0 with target 27
If you read the xy coordinates at the rotational position of ° 180 °, both V
The concentricity of the inner diameter axes at the positions of the respective V supports 18a and 18b where the supports 18a and 18b are common datum axis straight lines can be known.

If the measured coordinate values of the inner diameter axis are related to this, the coaxiality deviation of the inner diameter axis with respect to the datum axis straight line, and the eccentricity and direction of the inner diameter axis in a cross section perpendicular to the arbitrary axis are three-dimensional. Calculated as coordinates.

Further, if the displacement gauge 37 is applied to the outer peripheral surface of any other disc and the outer peripheral surfaces / end surfaces of both flanges with respect to the same datum axis straight line and the circumferential runout is recorded, after sealing welding, It is possible to re-measure and estimate how the shape / position of the inner diameter axis is affected and changed. Separately, if the relationship between the inner diameter axis of the welding assembly partner parts (for example, the electron gun 1 and the collector 3) and the outer circumference and the flange is recorded,
It is possible to estimate the shape / positional relationship of the inner diameter axis of the entire assembly part. On the other hand, spiral pitch measurement can be explained as follows.

That is, the measurement item switching mechanism 22 is operated to mount an object to be measured (for example, a spiral) with its axis aligned parallel to the sliding direction of the scanning mechanism 12. When the image guide 24 is inserted into the object to be measured, the image of the spiral 4 seen from the inside of the object to be measured becomes a spiral shape.

When the image guide 24 is fixed in the axial direction and the scanning mechanism 12 is slid in the insertion direction into the object to be measured, the spiral image is diffused outward and converges on the spiral center in the escape direction. At this time, the spiral contour pattern sequentially passes through arbitrary points on the screen, and the pitch of the helix 4 can be measured by reading the position of the slide at the moment when it passes each time by the length measuring mechanism 13.

On the other hand, the contour image of the spiral 4 viewed from the axial direction is superposed in a spiral shape, and the contour which is a feature for pitch measurement does not always appear clearly on the screen. Therefore, attention is paid to the fact that the corner portion inside the spiral 4, which is relatively closest to the objective lens 37 at the tip of the image guide 24, has a higher reflected light level than the periphery. By the image processing, the peak level contour in the spiral pattern captures the moment when the above-mentioned predetermined arbitrary point is passed, and the length measuring mechanism 13
High-resolution pitch measurement is possible by reading the axial position with.

However, as the image guide 24,
Since it is not possible to obtain an extremely thin and long object other than using the aligned optical fiber bundles 38, a continuous image such as a SELFOC rod lens cannot be obtained, and the resolution is the same as that between the adjacent optical fiber bundles 38 and 39. Will depend on you. Therefore, coupled with the fact that the vicinity of the peak of the reflected light distribution of the spiral 4 does not always have a pointed shape but appears rather flat, the pitch measurement method that detects the moment when the peak level passes an arbitrary fixed point has a limit in resolution. is there.

When the image guide 24 having such an optical fiber bundle 38 is used, if two fibers adjacent to each other in the direction in which the spiral contour moves on the screen by slide scanning are selected as arbitrary fixed points, those fibers are selected. When the peak level passes through the middle, there is an instant when the light receiving levels of the fibers on both sides of the peak level become equal.

In the windows that separate and enclose the two fiber images, the slide position is moved and adjusted / controlled until the same level of received light is obtained at the same time, and the position of that point can be read by the length measuring mechanism 13. For example, the pitch of the spiral 4 can be measured sequentially. Next, the procedure of specific measurement and use of the spiral shape will be described.

First, the case of measuring the straightness of the helix 4 will be described. Before starting this measurement, a telescopic camera (not shown) provided in advance at the position of the target 27 is provided with a circular mark (not shown) whose diameter is known. The image is collimated at 28, and the image processing device 30 calibrates and stores the magnification per unit pixel. or,
Initial values such as the measurement pitch and the number of measurement points are written in the data area.

The slow wave circuit unit 2 to be measured has two adjusting V-shaped supports 18a on the slide table 11 of the scanning mechanism 12 so that the inner diameter axis of the helix 4 coincides with the optical axis of the telephoto camera 28. , 18b are aligned with the optical axis and clamped. The slow wave circuit unit 2 holds two pole pieces located at both ends of the helix 4 among a plurality of pole pieces arranged coaxially with the helix 4. Next, the slide table 11 is moved, and the target guide 23 is inserted through the spiral 4 on the opposite side of the axis until it reaches the end, and the preparation for measurement is completed.

When the measurement start button is pressed, the image processing device 3
When the value is 0, the threshold value is automatically adjusted and binarized so that the number of pixels of the transmitted light circular image of the target 27 input from the telephoto camera 28 becomes a value within an appropriate fixed range. The center position of the circular image is arithmetically processed as an xy coordinate value from the origin of the image, and the arithmetic result is stored in the memory and, at the same time, displayed on the monitor TV 31.

Subsequently, the slow wave circuit section 2 on the slide table 11 is sequentially sent at the preset required pitch and number of times, and the measurement is repeated. At this time, in order to eliminate the influence of the change in the reflectance of the inner surface of the spiral 4 and the vignetting, the threshold value of the image processing device 30 is set so that the target image is always input with a certain number of pixels. Alternatively, the light source device 2
The brightness level of 9 is automatically adjusted.

After the measurement of the required number of times is completed, the scanning mechanism 1
Stop 2. Then, the mode of the image processing device 30 is switched to the axis correction mode, the z-axis tilt correction and the straightness deviation calculation are performed from the measurement point coordinates stored in the memory, and the result is as shown in FIG. It is displayed on the monitor TV 25. If necessary, the coordinate values of all the measurement points and the axis line diagram can be displayed for hard copy or output to a printer or plotter.

To measure the coaxiality deviation, V support 1
Loosen the clamp bar 20 of 8a, 18b to delay wave circuit unit 2
Is rotated 180 °, the slow wave circuit unit 2 is fixed again by the clamp bar 20, the target 27 is placed at the position of each V support 18a, 18b, and the xy coordinates are read by the telephoto camera 28. 0 average as determined middle point coordinates between the xy coordinates when the ° position _{(X m, Y m),} (X'm, Y'm) from, V support - DOO 18a, the axis of the pole piece position 18b The same V support 18 with the common data axis straight line
The concentricity deviations C and C ′ of the inner diameter axis at the positions a and 18b can be obtained by the following equation. C = 2 (X _m × X _m + Y _m × Y _m ) ^1/2 ,

C ′ = 2 (X ′ _m × X ′ _m + Y ′ _m × Y ′ _m ) ^1/2 (5) By performing coordinate conversion from the three-dimensional coordinates of the inner diameter axis measured previously so that the midpoint coordinates match, the coaxiality deviation of the inner diameter axis associated with the above datum can be obtained.

In connection with the above datum, in order to measure the radial runout of the outer circumference of an arbitrary pole piece and the runout of both flanges of the slow wave circuit unit 2 in the radial direction and the axial direction, After both flanges are axially stopped by stoppers (not shown) so that the pieces do not move axially on the V supports 18a and 18b, the clamp bar 20 is removed to hold the slow wave circuit unit 2 rotatably.

Next, a separately prepared displacement gauge 47 is applied to the location to be measured, and the shake during one rotation of each location is read and recorded. By relating this to the three-dimensional coordinate value of the spiral inner diameter axis measured earlier,
The position and shape of the inner diameter axis can be known from the shape.

Therefore, the electron gun 1 to be coaxially assembled
Also, for the collector 3 as well, if the circumferential runout or the three-dimensional coordinates of the same location with the inner diameter axis as the datum are separately measured by a general-purpose measuring machine, they will be affected by the mutual flange after sealing and welding. Even if the straightness changes in the easy longitudinal direction, the change in the concentricity of the inner and outer diameters for each cross section can be ignored because of the structure.Therefore, by measuring the circumferential runout or the three-dimensional coordinates at the same location again, The relational position and shape of the inner diameter axis of the spiral with respect to the electron gun 1 and the collector 3 are
In other words, the straightness deviation of the entire electron beam transmission path length can be verified. In the above-described measuring device 10, it is possible to measure the straightness of the spiral 4 that is extremely fine and long enough that a general optical sensor or the like cannot enter.

Furthermore, the helix 4 is the target guide 2
The straightness is measured while scanning in the direction of extracting 3. Therefore, the measurement can be performed without changing the pitch of the spiral 4. That is, target guide 2
When 7 is inserted into the helix 4 and measured, the pitch of the helix 4 may change due to the force of the helix 4 in the compression direction.
If 8 is extracted and measured, the shape of the helix 4 can be maintained and accurate measurement can be performed. Next,
The pitch measurement of the spiral 4 will be described.

First, the slow-wave circuit unit 2 is placed on the V supports 18a and 18b of the slide table 11 and clamped so that the axis of the spiral 4 of the slow-wave circuit unit 2 becomes parallel to the sliding direction at the z stage and the xy stage. Adjust your posture. Helix 4 of coating tube 40 at the tip of image guide 24
Then, the slide table 11 on which the slow wave circuit unit 2 is placed is brought closer to it, and finally inserted into the spiral 4 as shown in FIG. Then, the light from the light source device 29 that has passed through the light guide 39 of the image guide 24 is projected into the spiral 4, and the interior of the spiral 4 is illuminated.

The reflected light image on the inner surface of the spiral 4 is formed on the image forming surface 42 at the other end of the branching device 36 through the image guide 24. This image is displayed on the monitor TV 31 via the TV camera 43 and the image processing device 30 from the objective lens 44 focused on the image plane 42. The relative positional relationship between the image guide 24 and the spiral 4 in the axial direction at this time is displayed on the display device 16 connected to the length measuring mechanism 13.

Since the pitch displayed on the spiral 4 is not constant for all windings and has various pitches according to the required specifications depending on the winding position, the azimuth for designating the pitch is determined. Therefore, it is necessary to measure the pitch of the helix 4 in accordance with its azimuth.

Then, in order to facilitate the observation, the spiral 4
If the relative azimuths of the TV camera 43 and the helix 4 are aligned so that the line connecting the center and the azimuth for measuring the pitch is horizontal on the screen of the monitor TV 31 as shown in FIG. When the wave circuit unit 2 feeds in a direction away from the image guide 24, the point to be measured of the spiral image moves horizontally on the monitor TV 31 so as to converge toward the center of the spiral 4.

If an observation measuring point is provided on the system path of the point to be measured of the image to capture the moment when the contour of the same portion of each turn of the spiral 4 passes, and the position at that time is read by the length measuring mechanism 13, The pitch of helix 4 is required. Therefore, as the specific contour of each turn, a portion where the reflected light level at the corner of the inner surface of the helix 4 exhibits a peak is selected, and two appropriate adjacent fibers on the moving system path of the specific contour image are selected from the image guide image. Each image is individually surrounded by windows W1 and W2 to make a measurement point.

FIG. 9 shows the distribution of the reflection level of the spiral 4 on the path of the contour image moving system passing through the observation measurement points, and the measurement scanning of the scanning mechanism 13 and the two observation measurement point windows in accordance with the gradual increase of the binarization level of the reflected light. A tendency of white (over threshold) pixels is shown.

Before starting the actual measurement, the image processing device 3
It is necessary to set an initial condition of 0. When there is a peak of the reflected light level of the specific contour near the visual measurement point, a binarization level is set as an initial value such that all the pixels in each fiber image area in the two windows W1 and W2 become white. Other necessary initial values are also preset according to a predetermined flowchart.

Prior to the measurement, the image guide 24 is inserted while the tip thereof penetrates the helix 4 to a position just past the winding start (0th turn) of the opposite end while the monitor TV 31 is checking.

When the start button is pressed, light is emitted from the optical fiber bundle 39, and the image of the spiral 4 is formed on the image forming surface 42 through the objective lens 37. In this image, since the objective lens 37 is arranged at the eccentric position, the spiral 4
It can be captured at an angle with respect to the axis direction of, and the spirals 4 do not overlap and appear.

The formed image is picked up by the TV camera 43. The image signal output from the TV camera 43 is sent to the image processing apparatus 30, and the image processing apparatus 30 receives the image signal.
Converts the image signal into image data, extracts the portion of the window W1 in this image data, and sends it to the monitor TV31. Further, the image processing apparatus 30 compares the gray level of all the pixels in the window W1 with the initially set threshold value and counts the number of pixels having the white level.

The reflected light observed by the image guide 24 has a maximum peak at a corner inside the helix 4. As shown in FIG. 9, the intensity distribution of the reflected light becomes higher as it is closer to the tip of the image guide 24. In the detection of each pitch of the spiral 4, the comparison of the gray level of all the pixels in the window W1 with the threshold value is shown in FIG. 10, and the number of pixels of the white level becomes "0" while the gray level is increased by 1 gray level. Repeat, and according to the number of white level pixels in the window W2 of the same threshold value in which the number of pixels in the window W1 becomes "0", the stepping motor 14 is switched from fast forward to 1 μm forward and the slide base 11 is shown in the figure. Send to the left.

As shown in the figure, the comparison between the gray level of all the pixels in the window W2 and the threshold value is performed by increasing the threshold value by one gray level and the white level pixels of the window W1 and the window W2. The slide base 11 is repeatedly fed until the number becomes “0” at the same time.

In each of the windows W1 and W2, when the number of pixels of the white level becomes "0", the position of the helix 4 can be obtained by reading the display device 16 connected to the measuring mechanism 13. However, this pitch is determined from the position of the spiral 4 detected previously.

As described above, the image guide is inserted into the spiral 4 and moved, and the spiral 4 is detected by the image data picked up through the image guide 24. Based on the detected position, the moving length by the scanning mechanism 13 is determined. Since the pitch of the helix 4 is obtained, the pitch of the helix 4 can be accurately measured without destroying the slow wave circuit unit 2 even when the helix 4 is still inserted in the slow wave circuit unit 2.

In this case, the pitch can be measured even when the inner diameter of the spiral 4 is narrow and long, and the pitch can be measured reliably even if the pitch is not constant. Since the image guide 24 uses the optical fiber bundles 38 and 39, it is not affected by temperature changes and electromagnetic fields. The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.

For example, the object to be measured may be a thin tube other than the spiral 4. The same method can be used if the same irregularity shape such as an extremely elongated hole or the inner diameter axis of a tubular object is a narrow space that is continuous in the lengthwise direction, and the pitch and spacing of deep portions.

Even if the inner diameter of the object to be measured is larger than the outer diameter of the image guide 24, if a guide tube that fits the inner diameter of the image guide 24 is inserted into the image guide 24 and used, it can be used for other objects to be measured having different inner diameters. Can also be applied.

[0099]

As described above, according to the present invention, a telephoto camera collimates a target integrated with a flexible light guide which is smoothly inserted into the inner diameter of an ultra-thin object to be measured, and its light is collimated. By reading the three-dimensional coordinates of the inner diameter axis while sliding the DUT on the axis, the straightness deviation of the axis and the coaxial deviation with respect to the related external datum feature,
You can verify the circumferential runout.

Further, since the straightness deviation with respect to the entire electron beam transmission system path after the seal welding can be indirectly measured and verified from the outside, the guarantee of the geometrical quality which could not be achieved in the past can be obtained by the performance inspection of the final process. You can know without waiting.

Similarly, by inserting an ultra-thin image guide and capturing an image of the inside of the helix in the axial direction with a camera, the image guide and the helix are relatively moved in the axial direction to repeatedly observe the characteristic points of each turn of the helix. By
Other methods can non-destructively measure the pitch of a helix, neither probing nor seeing through.

Then, these measurements can be realized by one device and by simple switching means, the shape of the spiral can be comprehensively evaluated, the measurement cost is reduced, and the object to be measured is not moved. Therefore, various effects such as improved reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a spiral shape measuring apparatus showing an embodiment of the present invention.

FIG. 2 is a front view showing a V support holding a slow wave circuit unit of the embodiment.

FIG. 3 is a cross-sectional view showing a tip portion of a target guide of the same embodiment.

FIG. 4 is a configuration diagram of an image guide of the embodiment.

FIG. 5A is a vertical cross-sectional view of the tip of the image guide of the embodiment. (B) is a front view of the tip of the image guide of the embodiment.

FIG. 6 is an explanatory diagram showing straightness deviation of the embodiment.

FIG. 7 is a view showing the insertion state of the image guide of the embodiment.

FIG. 8 is a view of the same example displayed through an image guide.

FIG. 9 is a diagram showing the intensity of reflected light from a helix in the example.

FIG. 10 is a view for explaining the action of spiral position detection of the embodiment.

FIG. 11 is a main configuration diagram of a traveling wave tube of the embodiment.

FIG. 12 is an explanatory diagram showing a conventional measuring method.

[Explanation of symbols]

4 ... helix (measurement object), 12 ... scanning mechanism, 13 ... length measuring mechanism, 16 ... display device, 22 ... measurement item switching mechanism, 2
3 ... Target guide, 24 ... Image guide, 27 ...
Target, 28 ... Telephoto camera, 29 ... Light source device, 30
... image processing device, 31 ... monitor TV, 32 ... printer,
43 ... TV camera.

Claims (1)

[Claims] 1. A target guide which holds a target illuminated on a virtual axis of a spiral-shaped object to be measured and is inserted into the object to be measured, and a target guide which is arranged in parallel with the target guide and is inserted into the object to be measured. Image guide, a target guide and a measurement item switching means for switching the image guide to insert the image guide into the object to be measured, a target guide imaging means for imaging the target guide, and the image guide. An image guide image pickup means for picking up an image, a scanning means for moving the object to be measured, the target guide, and the image guide on the virtual axis of the object to be measured in the object to be measured, and the target guide image pickup means. Display means for displaying the output, computing means for computing the position of the target, and operating means for the computing means. The output means for outputting the straightness of the helix from the result and the position for each pitch in the object to be measured are detected from the image data obtained by the image pickup of the image guide image pickup means, and the scanning means is operated based on the position for each pitch. A spiral shape measuring device, comprising: a length measuring unit for obtaining a pitch of a spiral from a moving length.