JP2009047509A - Outer diameter measuring device and optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an outer diameter measuring device capable of measuring an outer diameter of a hollow part. <P>SOLUTION: This outer diameter measuring device includes a light beam scanning means 21 for scanning with a light beam, a light receiving means 23 for collecting a light beam transmitted through a scanning surface and outputting a corresponding electric signal, and a processing means 74 for calculating the width of a measuring object from the electric signal when arranging the measuring object in the middle of the scanning light beam. The measuring device also includes two ladder type prisms 31, 32 arranged oppositely so that each optical axis becomes parallel, and a holding block 33 for holding the two ladder type prisms 31, 32. The measuring object is arranged in a space whose one side is restricted by the holding block, in a space scanned with the light beam between the two ladder type prisms. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an outer diameter measuring apparatus that measures the outer diameter of a measurement object by scanning a light beam and detecting a period during which the light beam is blocked by the measurement object, and an optical element used therefor, in particular, the axis is The present invention relates to an outer diameter measuring apparatus for measuring an outer diameter of a shaft in a recessed portion and an optical element used therein.

  In order to measure the outer diameter of a cylindrical object and the length of a plate-shaped object in a non-contact manner, the object to be measured is placed in a light beam scanned in parallel and the length is measured by the width of the blocked light beam. Diameter measuring devices are widely used. FIG. 1 is a diagram showing a basic configuration of an outer diameter measuring apparatus.

  In FIG. 1, reference numeral 711 denotes a light beam generator for generating a parallel light beam, which is generally a combination of a semiconductor laser and a collimator lens. A polygon mirror 712 rotates a precise polygon mirror at a constant speed to deflect the light beam at a constant angular velocity. Reference numeral 713 denotes an fθ lens that changes the direction of the deflected light beam so as to be parallel to the axis, and moves, that is, scans in a direction perpendicular to the axis at a constant speed. A converging lens 72 condenses the scanned light beam. A photosensor 73 receives the light beam collected by the condenser lens 62 and converts it into an electrical signal. 74 processes the electrical signal to calculate the width at which the light beam is blocked.

  In FIG. 1, reference numeral 700 denotes an object to be measured. By disposing the object to be measured 700 in the scanning beam, the scanning light beam is interrupted only during a period in which the scanning beam scans the object to be measured 700. The intensity of the electrical signal from the light also changes accordingly. Therefore, if the period during which the intensity of the electrical signal is reduced is detected, the width at which the light beam is blocked is obtained by multiplying the scanning speed of the scanning beam.

  Since the outer diameter measuring apparatus of FIG. 1 is described in Patent Document 1, further detailed description thereof is omitted.

  FIG. 2 is a cross-sectional view of an example of a component to be measured. Reference numeral 13 is a main portion, and a rotating shaft 11 is provided. The periphery of the main portion 13 extends around the rotation shaft 11. In other words, the rotating shaft 11 protrudes from the main portion 13, but since the peripheral portion of the main portion 13 also protrudes, the shaft is in a recessed portion.

  High accuracy is required for the outer diameter of the rotating shaft of the above parts. Therefore, it is required to measure the outer diameter of the rotating shaft 11 with an outer diameter measuring apparatus as shown in FIG.

JP-A-6-265319

  However, as shown in FIG. 2, the periphery of the main portion 13 protrudes around the rotating shaft 11 and the light beam cannot be scanned across the rotating shaft 11. There is a problem that measurement cannot be performed with the apparatus.

  An object of the present invention is to solve such a problem, and to measure the outer diameter of a part to be measured of a member whose other part protrudes around the part to be measured as shown in FIG. .

  In order to achieve the above object, the outer diameter measuring apparatus of the present invention uses an optical element that holds two ladder prisms in a predetermined positional relationship with a holding block. Specifically, two ladder prisms are arranged so that their optical axes are parallel and symmetrical with respect to (the axis of) the object to be measured.

  That is, the outer diameter measuring apparatus according to the present invention includes a light beam scanning unit that scans a light beam with a predetermined surface of the space as a scanning surface, and condenses the light beam that has passed through the scanning surface to obtain an intensity of the light beam. A light receiving means for outputting a corresponding electrical signal; and a scanning period of the light beam scanning means is derived from the electrical signal when an object to be measured is placed in the middle of the scanned light beam. And a processing means for calculating the width of the object to be measured based on the blocking period, and two ladder prisms arranged opposite to each other so that the optical axes are parallel to each other, A scanning block that includes a holding block that holds the two ladder-type prisms, and the light beam is incident on one of the two ladder-type prisms and reflected by a reference-side prism surface. , The other scanning side After being reflected by the prism surface and incident on the other of the two ladder prisms, reflected by the scanning prism surface and then reflected by the other reference prism surface and emitted. The object to be measured is arranged in a space where the light beam is scanned between the scanning-side prism surfaces of the ladder-type prism, and one of which is limited by the holding block.

  The optical element of the present invention includes first and second ladder-type prisms arranged to face each other so that their optical axes are parallel to each other, and a holding block that holds the two ladder-type prisms. The two ladder-type prisms are configured such that a light beam traveling in a first direction parallel to the optical axis of the first ladder-type prism is reflected and emitted by a scanning prism surface, and then the second ladder-type prism is used. After being incident on the mold prism and reflected on the scanning prism surface, the holding block is disposed so as to travel in a direction 180 degrees opposite to the first direction, and the holding block is the scanning prism surface of the two ladder prisms The two ladder prisms are held so as to form a space between them.

  According to the present invention, since the rotation axis can be disposed between the scanning prism surfaces of the two ladder-type prisms, the outer diameter of the rotation axis can be measured.

  If the prism surface is sharp, it may be easily damaged. Therefore, a triangular prism may be bonded to the prism surfaces of the two ladder prisms, and the prism surface may be subjected to a reflection process.

  The outer diameter measuring device needs to measure the outer diameter of the object to be measured with high accuracy, and the positional relationship between the two ladder-type prisms is required to be highly accurate. Therefore, in the present invention, the two ladder-type prisms are held in a predetermined positional relationship by the holding block. Specifically, two ladder prisms are bonded to the holding block.

  According to the present invention, the outer diameter of the shaft provided in the recessed portion as shown in FIG. 2 can also be measured by the outer diameter measuring device.

  FIG. 3 is a diagram illustrating the optical element and the method of using the optical element according to the first embodiment of the present invention. FIG. 3A is a top view of the optical element, and FIG. 3B is a side view of the optical element. The relationship with the light beam of the outer diameter measuring device is shown, and the object to be measured is indicated by a broken line.

  As shown in FIG. 3, the two ladder prisms 31 and 32 are bonded and fixed to a holding member 33. The two ladder-type prisms 31 and 32 process a rectangular parallelepiped glass plate so that the opposing small surfaces are exactly 45 degrees with respect to the other surfaces. That is, processing is performed so as to form the prism surfaces 35 and 36. The holding block 33 is processed so that the opposing surfaces to which at least two ladder prisms 31 and 32 are bonded are parallel with high accuracy. Then, the two ladder-type prisms 31 and 32 are bonded so as to be symmetric with respect to the holding block 32 as shown in FIG. At this time, the prism surfaces 35 and 36 of the ladder-type prism 31 and the prism surfaces 35 and 36 of the ladder-type prism 32 are in an exact relationship of 90 degrees. The two ladder-type prisms 31 and 32 extend further upward from the upper surface of the holding block 32, and the lower side is limited by the upper surface of the holding block 32 in the space where the two ladder-type prisms 31 and 32 face each other. A hub rotating shaft 11 is arranged in the space at the time of measurement. The two ladder-type prisms 31 and 32 are located in a space between the rotating shaft 11 and the holding portion 12 at the time of measurement. The holding block 32 is fixed to the table 34 by bonding. Various modifications of the shape of the lower side of the holding block 32 and the fixing method to the base 34 are possible.

  The scanning beam output unit 21 includes the light beam generator 711, the polygon mirror 712, and the fθ lens 713 shown in FIG. 1 and outputs a scanning beam. The scanning beam receiving unit 22 is a part including the converging lens 72 and the photosensor 73 in FIG. 1, and receives the light beam and outputs an electrical signal. The signal processing circuit 23 corresponds to the signal processing circuit 74 in FIG. 1, and processes the electrical signal to calculate the width where the light beam is blocked, that is, the outer diameter of the rotating shaft 11.

  The scanning light beam output from the scanning beam output unit 21 is incident on the ladder-type prism 31, totally reflected by the lower reference-side prism surface 35, and travels upward in the ladder-type prism 31. Here, this direction of the ladder-type prism 31 is referred to as an optical axis. The same applies to the ladder-type prism 32. The scanning light beam is totally reflected by the scanning-side prism surface 36 on the upper side of the ladder-type prism 31 and is emitted horizontally from the ladder-type prism 31. Therefore, as shown in FIG. 3A, the light beam is scanned in the horizontal direction.

  The light beam enters the ladder-type prism 32, is totally reflected by the upper scanning-side prism surface 36, and travels down the ladder-type prism 32 along the optical axis. The scanning light beam is totally reflected by the reference prism surface 35 below the ladder-type prism 32, is emitted horizontally from the ladder-type prism 32, and enters the scanning beam light receiving unit 22.

  As indicated by the broken line, at the time of measurement, the rotating shaft 11 as the measurement target is arranged in a space sandwiched between the two ladder prisms 31 and 32 in the space above the holding block 33. At this time, the two ladder-type prisms 31 and 32 are located in the space between the rotating shaft 11 and the holding portion 12 and thus do not interfere with each other. Since the scanning light beam emitted horizontally from the ladder-type prism 31 is blocked by the rotating shaft 11, the outer diameter of the rotating shaft 11 can be measured.

  4A and 4B are diagrams showing the configuration of the optical element and the path of the scanning light beam according to the second embodiment of the present invention, where FIG. 4A is a top view and FIG. 4B is a side view. This optical element is used by being fixed to a table 34 as in FIG.

  As in the first embodiment, the optical element of the second embodiment is obtained by bonding two ladder prisms to the holding block 33 in a predetermined positional relationship, but the following points are different from the first embodiment. .

  Each ladder-type prism includes first members 41 and 46 each having a prism surface 48 formed thereon, second members 42 and 45 having opposing surfaces 48 and 49, and triangular prisms 43 and 44, respectively. It consists of. A reflective coating layer is formed on the prism surfaces 48 and 49 of the second members 42 and 45. The first members 41 and 46 and the second members 42 and 45 are bonded by the prism surface 48 to form a single plate. Further, triangular prisms 43 and 44 are bonded to the prism surfaces 49 of the second members 42 and 45 to form a rectangular parallelepiped ladder type prism. The ladder-type prism is a rectangular parallelepiped, but is referred to as a ladder-type prism here. As described above, since the reflective surfaces are provided on the prism surfaces 48 and 49, the scanning light beam incident on one of the ladder-type prisms is reflected by the prism surface 48 and along the optical axis as shown in the figure. Then, the light is reflected by the prism surface 49 and emitted from the ladder-type prism, and the object to be measured (the rotating shaft 11) is scanned. The scanning light beam enters the ladder-type prism, is reflected by the prism surface 49, travels downward along the optical axis, is reflected by the prism surface 48, and is emitted from the ladder-type prism. Others are the same as the first embodiment.

  In the second embodiment, since the ladder-type prism is a rectangular parallelepiped, the prism portion is less likely to be damaged than the ladder-type prism of the first embodiment.

  Although the embodiment of the present invention has been described above, it goes without saying that various modifications are possible. In particular, the shape and manufacturing method of the ladder prism can be various.

  The present invention is applicable to any case when detecting the outer diameter of the shape provided in the recessed portion.

It is a figure which shows schematic structure of an outer diameter measuring apparatus. It is a figure which shows the cross-sectional shape of components which have a rotating shaft in the recessed part made into a measuring object by this invention. It is a figure which shows the structure of the outer diameter measuring apparatus of 1st Embodiment of this invention, the optical element used there, and the path | route of a light beam. It is a figure which shows the optical element used with the outer diameter measuring apparatus of 2nd Embodiment of this invention, and the path | route of a light beam.

Explanation of symbols

11 Rotating shaft (measurement target)
31, 32 Ladder type prism 33 Holding block 35 Reference side prism surface 36 Scan side prism surface

Claims (4)

A light beam scanning means for scanning a light beam with a predetermined plane of space as a scanning plane;
A light receiving means for collecting the light beam that has passed through the scanning surface and outputting an electrical signal corresponding to the intensity of the light beam;
A cutoff period of the light beam is derived from the electrical signal when the measurement object is arranged in the middle of the scanned light beam, and the measurement object is based on the scanning speed of the light beam scanning means and the cutoff period. In the outer diameter measuring device comprising a processing means for calculating the width of
A scanning plane moving element comprising: two ladder prisms arranged opposite to each other so that the optical axes are parallel; and a holding block holding the two ladder prisms;
The light beam enters one of the two ladder-type prisms, is reflected by the reference-side prism surface, is reflected by the other scanning-side prism surface, and then exits, and then the two ladder-type prisms After being incident on the other side of the light source and reflected by the scanning side prism surface, then reflected and emitted by the other reference side prism surface,
The object to be measured is disposed in a space where the light beam is scanned between the scanning prism surfaces of the two ladder prisms, one of which is limited by the holding block. Outside diameter measuring device.   The outer diameter measuring apparatus according to claim 1, wherein a triangular prism is bonded to a prism surface of the two ladder-type prisms, and the prism surface is subjected to a reflection process. First and second ladder-type prisms arranged to face each other so that their optical axes are parallel, and a holding block for holding the two ladder-type prisms,
The two ladder-type prisms are configured such that a light beam traveling in a first direction parallel to the optical axis of the first ladder-type prism is reflected by a scanning prism surface and emitted, and then the second ladder-type prism is used. After being incident on the prism and reflected by the surface of the scanning prism, the prism is arranged so as to travel in a direction 180 degrees opposite to the first direction,
The optical element, wherein the holding block holds the two ladder prisms so as to form a space between the scanning side prism surfaces of the two ladder prisms.   The optical element according to claim 3, wherein a triangular prism is bonded to a prism surface of the two ladder-type prisms, and the prism surface is subjected to a reflection process.

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