Optical measurement device, optical measurement method, and rotating machine

1. An optical measurement device comprising:

a pair of first fiber bundles having a pair of first light-emitting fibers, distal ends of which are arranged at a specified interval, and a pair of first light-receiving fibers, distal ends of which are arranged at the specified interval, in a light sensor, the pair of first fiber bundles being arranged to be slanted to respectively form two sides of a triangle in triangulation;

a pair of second fiber bundles having a pair of second light-emitting fibers, distal ends of which are arranged at the specified interval, and a pair of second light-receiving fibers, distal ends of which are arranged at the specified interval, in the light sensor, the pair of second fiber bundles being arranged in parallel with each other;

a light source that outputs light to the pair of first light-emitting fibers and the pair of second light-emitting fibers to emit two slanted light beams from the pair of first light-emitting fibers and emit two parallel light beams from the pair of second light-emitting fibers, wherein

a target of the light emitted from the first light-emitting fibers and the second light-emitting fibers is provided on an outer peripheral surface of a rotary member, reflects the two slanted light beams to the pair of first light-receiving fibers, respectively, and reflects the two parallel light beams to the pair of second light-receiving fibers, respectively;

a pair of first light-receiving elements each of which is connected to the corresponding one of the pair of first light-receiving fibers and detects intensity of the light received by the first light-receiving element:

a pair of second light-receiving elements each of which is connected to the corresponding one of the pair of second light-receiving fibers and detects intensity of the light received by the second light-receiving element; and

a computation unit that performs calculation including the specified interval affected by thermal elongation, using four waveforms indicating changes in the intensity respectively detected by the pair of first light-receiving elements and the pair of second light-receiving elements.

2. The optical measurement device according to claim, wherein

the computation unit

calculates a first time difference from two times of a rising edge and a falling edge of each of the four waveforms and calculates a peripheral speed of the target, using one of the four first time differences or an average of two or more of the four first time differences,

calculates a second time difference from two times at which the target passes by the two parallel light beams using two of the waveforms detected by the pair of second light-receiving elements and calculates the specified interval affected by thermal elongation using the second time difference, and

calculates a third time difference from two times at which the target passes by the two slanted light beams using two of the waveforms detected by the pair of first light-receiving elements and calculates distance from the distal ends of the pair of first light-emitting fibers to the target using the third time difference.

3. The optical measurement device according to claim 2 , wherein

the light source has a first light source that outputs first light to the pair of first light-emitting fibers and a second light source that outputs second light with a wavelength different from a wavelength of the first light to the pair of second light-emitting fibers, and

the optical measurement device further includes

a first filter that is provided between the pair of first light-receiving fibers and the pair of first light-receiving elements and transmits only the first light and

a second filter that is provided between the pair of second light-receiving fibers and the pair of second light-receiving elements and transmits only the second light.

4. A rotating machine comprising the optical measurement device according to claim 3 .

5. The optical measurement device according to claim 1 , wherein

the light source has a first light source that outputs first light to the pair of first light-emitting fibers and a second light source that outputs second light with a wavelength different from a wavelength of the first light to the pair of second light-emitting fibers, and

the optical measurement device further includes

a first filter that is provided between the pair of first light-receiving fibers and the pair of first light-receiving elements and transmits only the first light and

a second filter that is provided between the pair of second light-receiving fibers and the pair of second light-receiving elements and transmits only the second light.

6. A rotating machine comprising the optical measurement device according to claim 1 .

7. A rotating machine comprising the optical measurement device according to claim 2 .

8. A rotating machine comprising the optical measurement device according to claim 5 .

9. An optical measurement method comprising:

arranging, in a light sensor, a pair of first fiber bundles having a pair of first light-emitting fibers, distal ends of which are arranged at a specified interval, and a pair of first light-receiving fibers, distal ends of which are arranged at the specified interval, such that the pair of first fiber bundles are slanted to respectively form two sides of a triangle in triangulation;

arranging, in the light sensor, a pair of second fiber bundles having a pair of second light-emitting fibers, distal ends of which are arranged at the specified interval, and a pair of second light-receiving fibers, distal ends of which are arranged at the specified interval, such that the pair of second fiber bundles are in parallel with each other;

outputting light from a light source to the pair of first light-emitting fibers and the pair of second light-emitting fibers to emit two slanted light beams from the pair of first light-emitting fibers and emit two parallel light beams from the pair of second light-emitting fibers;

reflecting the two slanted light beams to the pair of first light-receiving fibers, respectively, and reflecting the two parallel light beams to the pair of second light-receiving fibers, respectively, using a target provided on an outer peripheral surface of a rotary member;

detecting, using each of a pair of first light-receiving elements connected to the corresponding one of the pair of first light-receiving fibers, intensity of the light received by the first light-receiving element;

detecting, using each of a pair of second light-receiving elements connected to the corresponding one of the pair of second light-receiving fibers, intensity of the light received by the second light-receiving element; and

performing calculation including the specified interval affected by thermal elongation, using four waveforms indicating changes in the intensity respectively detected by the pair of first light-receiving elements and the pair of second light-receiving elements.

10. The optical measurement method according to claim 9 , further comprising:

calculating a first time difference from two times of a rising edge and a falling edge of each of the four waveforms and calculating a peripheral speed of the target using one of the four first time differences or an average of two or more of the four first time differences;

calculating a second time difference from two times at which the target passes by the two parallel light beams using two of the waveforms detected by the pair of second light-receiving elements and calculating the specified interval affected by thermal elongation using the second time difference; and

calculating a third time difference from two times at which the target passes by the two slanted light beams using two of the waveforms detected by the pair of first light-receiving elements and calculating distance from the distal ends of the pair of first light-emitting fibers to the target using the third time difference.