JP2006184217A - Centering system and centering method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centering system and the like, capable of easy and accurate centering, using a laser. <P>SOLUTION: For centering, the rotation reference position of a reflecting mirror 26 is first determined with an auxiliary laser beam. Then, the laser beam from a laser luminescence means 21 is refracted and irradiated, by the reflecting mirror 26 on the inner surface of a second guide metal 15, the laser beam reflected from the second guide metal 15 is received with a laser receiving means 23. The time the laser beam returns to the laser-receiving means 23 is measured by a time measuring means 25a. Then a rotating disk 27 is rotated, and the time is measured likewise at that time (measurement point 2), when the reflecting mirror 26 has turned by 180 degrees. Based on this result, positional deviation (d) in the directions of the measurement point 1 and the measurement point 2 of the second guide metal 15 from the measured difference, between the measurement point 1 and the measurement point 2, is obtained. Measurement is conducted in this manner for a plurality number of times, so that the center position of the second guide metal 15 is specified. Likewise, the center position of the third guide metal 16 is specified. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a centering device and a centering method for performing centering measurement for positioning of a guide metal in assembly work of a rotary main shaft such as a water turbine generator. Specifically, the centering device can be positioned at an arbitrary position by a laser emitting unit that generates laser light, a laser receiving unit that receives laser light, a reflecting mirror that reflects the laser, and a rotation that rotates the reflecting mirror. Means, a time measuring means for measuring the time until the laser light from the laser emitting means is received by the laser emitting means, and a distance from the reflecting mirror to the inner surface of the guide metal based on the measurement result of the time measuring means And a control means for controlling the laser light emitting means and the rotating means. When centering, the laser light emitting means is disposed in the upper center portion of the guide metal, and the reflecting mirror is disposed on the guide metal. It is installed in the center, and the laser beam from the laser emitting means is refracted by the reflecting mirror onto the inner surface of the guide metal, and the laser beam reflected from the inner surface of the guide metal is reflected. The light is reflected by the reflecting mirror, received by the laser receiving means, the time from when the laser light from the laser emitting means is received by the laser receiving means is measured, and the distance from the reflecting mirror to the inner surface of the guide metal is calculated. And a centering device that can easily and accurately center by rotating the reflecting mirror and measuring a plurality of points to identify the center position of the guide metal. is there.

  In the hydroelectric power plant of the hydroelectric power plant, the turbine and the generator are connected by a connecting shaft. When assembling the power generation device, it is necessary to use a centering device in order to center the rotation main shaft on the same center line.

  Conventionally, in the vertical axis turbine assembly work, the wire centering method is mainly employed for positioning the guide metal.

  FIG. 8 is a schematic view showing a conventional centering measuring apparatus. As shown in FIG. 8, a piano wire 2 with a weight 7 attached to the tip is suspended from the axis of the center ring mount 1 supported by the uppermost part 10 of the cylindrical hole, and a scaffold (not shown) corresponding to each measurement unit. 2), the inside micrometer 4 which is a measuring rod is put on the measuring surface 3 and the piano wire 2 by hand on the scaffold, and the measurer receives the electric sound when the inside micrometer 4 contacts the piano wire 2 by the receiver 5 I read the scale of the inside micrometer 4 at that time and measured it.

  When such a centering measuring device is used, it is extremely difficult to measure, and it has to be relied on by highly skilled technicians, and there are also issues such as safety considerations necessary for work on a scaffold in a high place. .

  In order to solve this, there has been proposed a centering measuring device that performs centering measurement of a rotating main shaft of a water turbine generator or the like using a controllable measuring device (see, for example, Patent Document 1).

  In this case, the centering measuring device is attached to a horizontally supported suspension base that can move up and down substantially parallel to the piano wire suspended vertically from the center of the top of the cylindrical hole and can be positioned at any vertical position. This measuring device has a non-contact XY position sensor that surrounds the piano wire in the center and detects the position of the piano wire, can be expanded and contracted by gravity balance in a symmetrical manner in the left-right direction, and can be expanded and contracted arbitrarily It has a pair of measuring arms that can be positioned. A slider device is attached to the tip of the measuring arm, and the tip of the slider device has a steady contact terminal with an elastic member at the tip and a contact that can be extended and contracted in parallel with the steady contact terminal. The probe is fixed.

  When measuring, position a measuring device with a non-contact XY position sensor that detects the position of the piano wire on a horizontally supported suspension base at an arbitrary vertical position almost parallel to the piano wire. A steady contact terminal with a first slider device attached to one end of the measuring arm is attached to the tip of the measuring arm, and the first measuring device is attached to one end of the measuring arm. Is extended by a predetermined distance (the design distance from the piano wire to the inner surface of the cylindrical hole is known) to a position where it contacts the inner surface of the opposite cylindrical hole and positioned at that position, Along with this, the second slider device at the tip of the other measuring arm to which the contact probe is fixed is extended and extended until the contact terminal contacts the inner surface of the cylindrical hole. In the state where each contact terminal is in contact with the inner surface of the cylindrical hole, the tip of the contact probe attached to the tip of the second slider device is brought into contact with the inner surface of the cylindrical hole and positioned at that position. The axial position of the measuring device of the suspension frame with respect to the piano wire by the non-contact XY position sensor, the length from this axial position to the tip reference position of the second slider device to which the contact probe is attached, and the contact probe It is possible to automatically measure the radius of the cylindrical hole or the deviation of the radius from the detected tip reference position and the measured length to the inner surface of the cylindrical hole without using humans for measurement.

Japanese Patent Laid-Open No. 8-340662 (pages 4, 5 and 1)

  However, when the centering measuring apparatus shown in FIG. 8 is used, there is a problem that the measurement requires time and skill.

  In addition, there is a problem that the application scale is limited due to the size of the measuring device.

  In the case of Patent Document 1, there is a problem in terms of cost because the measuring device is complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a centering device and a centering method capable of easily and accurately centering using a laser beam.

  A centering device according to the present invention is a centering device for positioning a guide metal having a cylindrical inner surface in assembly work of a large rotary shaft installed vertically, a laser emitting means for generating laser light, and a laser Laser receiving means for receiving light, reflecting mirror for reflecting the laser, rotating means for rotating the reflecting mirror that can be positioned at any position, and laser light from the laser emitting means are received by the laser receiving means. A time measuring means for measuring the time until, a calculating means for calculating a distance from the reflecting mirror to the inner surface of the guide metal based on a measurement result of the time measuring means, a control means for controlling the laser emitting means and the rotating means, When the centering is performed, the laser light emitting means is disposed in the upper center portion of the guide metal, and the reflecting mirror is disposed on the guide metal. It is disposed to the eccentric part.

  For example, it further includes reference setting means for defining the rotation reference point of the reflecting mirror. The reference setting means includes an auxiliary light beam generating means for generating auxiliary laser light, a disk for fixing the reflecting mirror, and an auxiliary reflecting mirror for reflecting the auxiliary laser light provided on the upper surface of the disk for centering. At this time, the disk is rotated so that the auxiliary laser beam generated by the auxiliary light beam generating unit is irradiated to the auxiliary reflecting mirror, and the disk position where the reflected light reflected from the auxiliary reflecting mirror is received by the laser light receiving unit is determined. It is defined as the rotation reference point of the reflector.

  Further, for example, the reference setting means includes an auxiliary light beam generating means for generating auxiliary laser light, a disk for fixing the reflecting mirror, a hole for passing the auxiliary laser light provided on the disk, and the auxiliary laser light that has passed through the hole. An auxiliary light receiving means for receiving light, and when centering, the auxiliary laser generated by the auxiliary light ray generating means is rotated so that the auxiliary laser light passes through the hole, and the auxiliary laser having passed through the hole by the auxiliary light receiving means. The position of the disk that receives light is defined as the rotation reference point of the reflecting mirror.

  In this invention, the laser light emitting means, the laser light receiving means, the reflecting mirror, the rotating means, the time measuring means, the calculating means, and the control means are provided, and the laser light emitting means is guided when centering. Located in the upper center of the metal, a reflecting mirror is installed at or near the center of the guide metal, and the laser beam from the laser emitting means is refracted and reflected from the inner surface of the guide metal by the reflecting mirror. The reflected laser light is reflected by the reflecting mirror, received by the laser receiving means, the time until the laser light from the laser emitting means is received by the laser receiving means is measured, and the distance from the reflecting mirror to the inner surface of the guide metal is measured. The distance is calculated, and the reflecting mirror is rotated, and a plurality of points are measured to identify the center position of the guide metal.

  As a result, the measurement does not require time and skill, and can be centered easily and accurately. Further, since the measuring device can be made small, the application range is wide, and further, the cost of the measuring device can be reduced.

  Further, the centering method according to the present invention is a centering method for positioning a guide metal having a cylindrical inner surface in an assembly operation of a large rotary shaft installed vertically, wherein the laser emitting means is disposed above the guide metal. It is placed in the center, and a reflecting mirror is installed at the center of the guide metal. The reflecting mirror refracts the laser light from the laser emitting means on the inner surface of the guide metal, and the laser light reflected from the inner surface of the guide metal is irradiated. Reflected by the reflecting mirror, received by the laser receiving means, measured the time until the laser light from the laser emitting means is received by the laser receiving means, and calculated the distance from the reflecting mirror to the inner surface of the guide metal, The center position of the guide metal is specified by rotating the reflecting mirror and measuring a plurality of points.

  For example, when centering, the rotation reference point of the reflecting mirror is defined using auxiliary laser light before measuring the time until the laser light from the laser light emitting means is received by the laser light receiving means. .

  In the present invention, the center position of the guide metal is specified by using a laser, so that measurement does not require time and skill as in the prior art, and centering can be performed easily and accurately. Become.

  According to the centering device and the centering method of the present invention, in the centering device, the laser light emitting means, the laser light receiving means, the reflecting mirror that reflects the laser, and the positioning of the reflecting mirror can be performed at any position. Rotating means, time measuring means for measuring the time until the laser light from the laser emitting means is received by the laser receiving means, and from the reflecting mirror to the inner surface of the guide metal based on the measurement result of the time measuring means And a control means for controlling the laser light emitting means and the rotating means. When centering, the laser light emitting means is disposed in the upper center portion of the guide metal, and the reflecting mirror is disposed on the guide metal. The laser beam from the laser emitting means is refracted and irradiated on the inner surface of the guide metal by the reflecting mirror. The laser light reflected from the surface is reflected by the reflecting mirror, received by the laser receiving means, and the time until the laser light from the laser emitting means is received by the laser receiving means is measured. The distance to the inner surface is calculated, the reflecting mirror is rotated, and a plurality of points are measured to determine the center position of the guide metal. And can be centered easily and accurately. Further, since the measuring device can be made small, the application range is wide, and the cost of the measuring device can be reduced.

  Hereinafter, a centering device and a centering method according to embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing a spindle assembly state of a hydroelectric generator. As shown in FIG. 1, the generator is installed in the upper part, and the water turbine is installed in the lower part. The generator main shaft 11 and the turbine main shaft 12 are connected via a connecting shaft 13. A generator rotor 17 is arranged in the middle of the generator main shaft 11. A water wheel propeller 18 is attached to the lower part of the water wheel main shaft 12. The water turbine propeller 18 is rotated by the water flow, and the water turbine main shaft 12 rotates the generator main shaft 11 via the connecting shaft 13 to generate power.

  The generator main shaft 11 is positioned by a first guide metal 14 and a second guide metal 15. The turbine main shaft 12 is positioned by a third guide metal 16. Here, the inner diameters of the first guide metal 14, the second guide metal 15, and the third guide metal 16 are, for example, 400 mm. The length of the generator main shaft 11 is about 4.5 m, the length of the water turbine main shaft 12 is about 1.6 m, and the length of the connecting shaft 13 is about 1.6 m.

  In this case, the generator main shaft 11, the water turbine main shaft 12, and the connecting shaft 13 are installed on the same center line. Therefore, the center positions of the first guide metal 14, the second guide metal 15, and the third guide metal 16 are specified by the centering device.

  FIG. 2 is a diagram illustrating a configuration example of the centering device according to the embodiment. As shown in FIG. 2, the centering device 100 includes a laser light emitting device 21, a prism 22, a laser light receiving device 23, a control unit 24, a time measuring unit 25 a, a dimension calculating unit 25 b, a reflecting mirror 26, and a rotating disk 27. A rotation drive unit 28, a pedestal 29, and auxiliary prisms 31 and 32.

  A laser transmitting / receiving unit including the laser light emitting device 21, the prism 22, the laser light receiving device 23, and the auxiliary prisms 31 and 32 is disposed on the horizontal table 20. In this case, a level adjusting member such as a level is provided to emit the laser beam vertically. The laser light emitting device 21 and the laser light receiving device 23 are connected to the control unit 24. The control unit 24 is connected to the time measuring unit 25 a and the rotation driving unit 28 and controls the rotation driving unit 28.

  In this case, the laser light receiving device 23 also functions as auxiliary light receiving means. When the laser light receiving device 23 receives the auxiliary laser light, the rotation reference position of the reflecting mirror 26 is determined, and the laser light emitting device 21 and the reflecting mirror 26 are synchronized.

  The time measuring means 25a measures the time until the laser light from the laser light emitting device 21 is refracted by the reflecting mirror 26, irradiates the inner surface of the second guide metal 15, is reflected, and returns to the laser light receiving device 23. To be made. The dimension calculating unit 25b calculates the distance from the reflecting mirror 26 to the inner surface of the second guide metal 15 based on the measurement result of the time measuring unit 25a.

  The reflecting mirror 26 is fixed on the rotating disk 27 and is rotated together with the rotating disk 27. The rotation of the rotary disk 27 is driven by the rotation drive unit 28. The rotation drive unit 28 uses a stepping motor, for example, and is fixed by a pedestal 29. The pedestal 29 is installed according to the position of the guide metal to be measured.

  The rotating disk 27 is provided with an auxiliary reflecting mirror 33 for detecting the rotational position. The auxiliary light beam is extracted from the laser light of the laser light emitting device 21 by the auxiliary prisms 31 and 32 as auxiliary light beam generating means, and this auxiliary light beam is reflected by the auxiliary reflecting mirror 33 and received by the laser light receiving device 23, and this position is measured. The rotation reference position of the rotating disk 27 is used. Measurement is performed by rotating a predetermined angle from this reference position.

  As shown in FIG. 2, the first guide metal 14, the second guide metal 15, and the third guide metal 16 are arranged at predetermined positions by a support 19a. Further, the horizontal position is determined by a horizontal holding member 19b that is movable in the horizontal direction. When centering with respect to the first guide metal 14, if there is a deviation of the second guide metal 15 or the third guide metal 16 due to the measurement, the second guide metal 15 or the third guide metal 16 is Move horizontally to adjust the center.

  FIG. 3 is a schematic diagram showing a method for defining the rotation reference point of the reflecting mirror. As shown in FIG. 3, an auxiliary reflecting mirror 33 for reflecting auxiliary laser light is provided on the upper surface of the rotating disk 27. The auxiliary reflecting mirror 33 is composed of, for example, a circular reflecting mirror. When centering, first, auxiliary laser light is extracted from the laser light of the laser light emitting device 21 by the auxiliary prisms 31 and 32 (see FIG. 2), and the rotating disk 27 is irradiated with the auxiliary laser light while rotating the rotating disk 27. . When this auxiliary laser beam is reflected by the auxiliary reflecting mirror 33 and received by the laser light receiving device 23, the rotation reference position of the rotating disk 27 (the rotation reference point of the reflecting mirror 26) when measuring this position is set. In this way, the laser light emitting device 21 and the reflecting mirror 26 are synchronized. And it measures while rotating only a predetermined angle from this reference position.

  FIG. 4 is a schematic diagram showing a method (part 2) for defining the rotation reference point of the reflecting mirror. As shown in FIG. 4, the rotating disk 27 is provided with a hole 27 a instead of the auxiliary reflecting mirror 33. A light receiving element 34 is provided below the rotating disk 27.

  When centering, first, the reflecting mirror 26 is rotated together with the rotary disk 27, and the auxiliary laser light emitted from the laser light emitting device 21 by the auxiliary prisms 31 and 32 (see FIG. 2) is received through the hole 27a. The element 34 is reached. A synchronization signal is generated from the light receiving element 34 that has received the laser light, and this synchronization signal is input to the control unit 24. The control unit 24 determines the rotation reference position (rotation reference point of the reflecting mirror 26) of the rotating disk 27 based on the input synchronization signal, and synchronizes the laser light emitting device 21 and the reflecting mirror 26. Then, control is performed so that measurement is performed while rotating by a predetermined angle from the reference position or while rotating.

  FIG. 5 is a schematic view showing a method (part 3) for defining the rotation reference point of the reflecting mirror. As shown in FIG. 5, the rotating disk 27 is provided with a hole 27 a instead of the auxiliary reflecting mirror, and the rotational driving force of the reflecting mirror 26 is applied not from the rotating disk 27 but from another rotational driving unit. A light receiving element 34 is provided below the rotating disk 27.

  FIG. 6 is a diagram illustrating a configuration example of the rotation driving unit. In this case, the reflecting mirror 26 is magnetically levitated by the repulsive force with the magnet 44 by energizing the coil 42 under the control of the control unit 24, and the reflecting mirror 26 and the rotating disk 27 are separated. As a result, the two are no longer connected to each other in rotation, so that only the reflecting mirror 26 can be rotated. The rotary disk 27 is driven to rotate by a motor 46. Further, when the energization to the coil 42 is released, the magnetic repulsive force disappears, so that the reflecting mirror 26 is lowered and the reflecting mirror 26 and the rotating disk 27 are mechanically integrated. At this time, both are driven to rotate simultaneously.

  In the method of defining the rotation reference point of the reflecting mirror shown in FIG. 5, when centering, first, the reflecting mirror 26 is fixed on the rotating disk 27 and rotated together, and auxiliary prisms 31 and 32 (see FIG. 2). When the auxiliary laser light extracted from the laser light emitting device 21 passes through the hole 27a and reaches the light receiving element 34, a synchronization signal is generated from the light receiving element 34. This synchronization signal is input to the control unit 24. Based on the input synchronization signal, the control unit 24 sets the rotation reference position of the rotating disk 27 (the rotation reference point of the reflecting mirror 26) when measuring this position. Then, only the reflecting mirror 26 is driven and rotated to a predetermined angle to perform measurement.

  Next, a centering method using the centering device 100 will be described with reference to FIGS. 2 and 7 described above. FIG. 7 is an explanatory diagram of centering measurement. FIG. 7A is a cross-sectional view of the second guide metal 15, and FIG. 7B is a plan view of the second guide metal 15.

  When assembling the hydroelectric generator, the centering device 100 is used to make the generator main shaft 11 and the water turbine main shaft 12 on the same center line, and the first guide metal 14, the second guide metal 15 and The center position of the third guide metal 16 is specified.

  First, the laser transmission / reception unit is installed on the horizontal base 20 on the first guide metal 14, and the laser light from the laser light emitting device 21 passes through the center portion (or the vicinity thereof) of the first guide metal. Thus, the horizontal position of the laser light emitting device 21 is determined.

  Next, the rotation drive unit 28 and the pedestal 29 are installed so that the reflecting mirror 26 comes to the center of the second guide metal.

  Next, the auxiliary prism 31 is positioned in the optical path of the laser beam. Laser light is generated from the laser light emitting device 21 under the control of the control unit 24, and this laser light is applied to the rotating disk 27 via the prism 22 and auxiliary prisms 31 and 32. At this time, the rotating disk 27 is driven to rotate under the control of the control unit 24. When the auxiliary reflecting mirror 33 provided on the rotating disk 27 reaches the irradiation position of the laser beam, the laser beam is reflected. The laser light reflected from the auxiliary reflecting mirror 33 is received by the laser light receiving device 23 via the auxiliary prisms 32 and 31 and the prism 22. In this case, when the laser light receiving device 23 receives light, the position of the rotating disk 27 is set as a reference position for rotation. For example, the position shown in FIG.

  At the reference position of the rotating disk 27, the laser light from the laser light emitting device 21 is irradiated to the reflecting mirror 26, refracted by the reflecting mirror 26, and irradiated to the inner surface of the second guide metal 15. The laser light reflected from the inner surface of the second guide metal 15 is received by the laser light receiving device 23 via the reflecting mirror 26 and the prism 22. In this case, the time for the laser light to return to the laser light receiving device 23 is measured.

  Further, the same measurement is performed again at the time (measurement point 2) when the rotating disk 27 is rotated by the control of the control unit 24 and the reflecting mirror 26 is inverted by 180 degrees. Based on the measurement result, the positional deviation d between the measurement points 1 and 2 of the second guide metal 15 is obtained from the measurement difference between the measurement points 1 and 2 of the second guide metal 15.

  This measurement operation is performed four times (four pairs), for example, and the center position of the second guide metal 15 is specified. And after calculating | requiring the deviation of the center of the X and Y direction, the 2nd guide metal 15 is moved and position adjustment is performed.

  Note that the radius is measured for each measurement point on the circumference of the second guide metal 15, the position deviation d is obtained, the second guide metal 15 is moved, and the position is adjusted. Good.

  Further, the third guide metal 16 is measured by the same method as described above, and the center position thereof is specified.

  As described above, in the present embodiment, the centering device 100 includes the laser light emitting device 21, the prism 22, the laser light receiving device 23, the control unit 24, the time measuring unit 25, the reflecting mirror 26, the rotating disk 27, A rotation drive unit 28, a pedestal 29, and auxiliary prisms 31 and 32 are provided.

  When centering, the laser emitting means is disposed at the upper center portion of the first guide metal 14, and the reflecting mirror 26 is disposed at the center portion of the second guide metal 15. Next, the rotation reference position of the reflecting mirror 26 is determined by the auxiliary laser light. Next, the reflecting mirror 26 refracts the laser light from the laser emitting means 21 on the inner surface of the second guide metal 15, and the laser light reflected from the inner surface of the second guide metal 15 is reflected by the reflecting mirror 26. The laser light receiving means 23 receives the light, the time measuring means 25a measures the time until the laser light from the laser light emitting means 21 returns to the laser light receiving means 23, and the dimension calculating means 25b takes the second guide from the reflecting mirror 26. The distance to the inner surface of the metal 15 is calculated, and the reflecting mirror 26 is rotated by a predetermined angle by the rotation driving unit 28, and a plurality of points are measured to identify the center position of the second guide metal 15. The center position of the third guide metal 16 is specified by the same method.

  As a result, the measurement does not require time and skill, and can be centered easily and accurately. Further, since the measuring device can be made small, the application range is wide, and the cost of the measuring device can be reduced.

  In the above-described embodiment, the centering device 100 uses the same laser generator 21 for the auxiliary laser beam and the measurement laser beam for determining the reference position of the rotary disk 27. However, the present invention is not limited to this. is not. The auxiliary laser beam may be generated using another laser generator.

  Moreover, although the centering apparatus 100 demonstrated the case where centering measurement was performed for positioning of a guide metal in the assembly operation | work of the rotating main shaft of a water turbine generator in the above-mentioned embodiment, it is not limited to this.

  As described above, the centering device and the centering method according to the present invention can be used for the purpose of measuring the centering for positioning the guide metal in the assembly work of the rotating main shaft such as a turbine generator.

It is the schematic which shows the spindle assembly state of a hydroelectric generator. It is a figure which shows the structural example of the centering apparatus of embodiment. It is the schematic which shows the method of prescribing | regulating the rotation reference point of a reflective mirror. It is the schematic which shows the method (the 2) which prescribes | regulates the rotation reference point of a reflective mirror. It is the schematic which shows the method (the 3) which prescribes | regulates the rotation reference point of a reflective mirror. It is a figure which shows the structural example of a rotation drive part. It is explanatory drawing of centering measurement. It is a figure which shows the structural example of the conventional centering measuring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Generator spindle, 12 ... Turbine spindle, 13 ... Connection shaft, 14 ... 1st guide metal, 15 ... 2nd guide metal, 16 ... 3rd guide Metal, 17 ... Generator rotor, 18 ... Turbine propeller, 19a ... Support, 19b ... Horizontal holder, 20 ... Horizontal base, 21 ... Laser light emitting device, 22. ..Prism, 23... Laser receiving device, 24... Control unit, 25 a... Time measuring means, 25 b. ... Hole, 28 ... Rotation drive part, 29 ... Base, 31, 32 ... Auxiliary prism, 33 ... Auxiliary reflector, 34 ... Light receiving element, 100 ... Centering device

Claims (6)

In a centering device for positioning a guide metal having a cylindrical inner surface in assembly work of a large rotary shaft installed vertically,
Laser light emitting means for generating laser light;
Laser receiving means for receiving the laser beam;
A reflecting mirror for reflecting the laser;
Rotating means that can be positioned at any position and rotates the reflecting mirror;
Time measuring means for measuring the time until the laser light from the laser light emitting means is received by the laser light receiving means;
Based on the measurement result of the time measuring means, calculating means for calculating the distance from the reflecting mirror to the inner surface of the guide metal;
Control means for controlling the laser light emitting means and the rotating means,
When centering, the laser emitting means is disposed at an upper central portion of the guide metal, and the reflecting mirror is disposed at the central portion of the guide metal. The centering device according to claim 1, further comprising reference setting means for defining a rotation reference point of the reflecting mirror. The reference setting means is
Auxiliary beam generating means for generating auxiliary laser light;
A disk for fixing the reflecting mirror;
An auxiliary reflecting mirror that reflects the auxiliary laser light provided on the upper surface of the disk;
When centering, the disk is rotated so that the auxiliary laser beam generated by the auxiliary beam generator is applied to the auxiliary reflector, and the reflected light reflected from the auxiliary reflector is received by the laser receiver. The centering device according to claim 2, wherein a disc position to be performed is defined as a rotation reference point of the reflecting mirror. The reference setting means is
Auxiliary beam generating means for generating auxiliary laser light;
A disk for fixing the reflecting mirror;
A hole for passing the auxiliary laser beam provided in the disk;
An auxiliary light receiving means for receiving the auxiliary laser light that has passed through the hole,
When centering, the disk is rotated so that the auxiliary laser light generated by the auxiliary light beam generating means passes through the hole, and the disk position for receiving the auxiliary laser light that has passed through the hole by the auxiliary light receiving means. The centering device according to claim 2, wherein the centering device is defined as a rotation reference point of the reflecting mirror. In a centering method for positioning a guide metal having a cylindrical inner surface in an assembly operation of a large rotary shaft installed vertically,
The laser emission means is disposed at the upper center of the guide metal, and the reflecting mirror is installed at or near the center of the guide metal,
The reflecting mirror refracts the laser light from the laser emitting means on the inner surface of the guide metal, the laser light reflected from the inner surface of the guide metal is reflected by the reflecting mirror, and received by the laser receiving means,
Measure the time until the laser light from the laser light emitting means is received by the laser light receiving means,
Calculate the distance from the reflecting mirror to the inner surface of the guide metal,
A centering method characterized by rotating the reflecting mirror and measuring a plurality of points to determine the center position of the guide metal. When centering, the rotation reference point of the reflecting mirror is defined using auxiliary laser light before measuring the time until the laser light from the laser light emitting means returns to the laser light receiving means. The centering method according to claim 5.

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