Optical Rotor Speed Sensing Without Rotational Imbalance
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Solution Overview
Problem
Existing methods for measuring the rotational speed of rotating bodies, such as turbochargers or gas turbines, face challenges due to the influence of magnetism, disturbance of rotational balance from added components, and inaccuracies from manual application of black paint, which can lead to uneven measurement.
Innovation Solution
A measurement system with a rotating body featuring a first and second measurement region on its surface, where the second region has a marking to reflect light differently, allowing accurate optical measurement without disturbing the rotational balance, and can be formed uniformly through machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hollow cap and through hole are added to the rotational shaft for optical sensor measurement, then rotational speed measurement is enabled, but rotational balance is disturbed during high-speed rotation
Solution Approach 1:
The invention applies a marking only to a specific local region (second measurement region) of the rotating body's outer surface, rather than modifying the entire structure. This localized marking changes light reflection properties in only the necessary area, enabling measurement while preserving the overall rotational balance of the component.
Solution Approach 2:
The invention extracts the measurement function from the structural components (hollow cap and through hole) and implements it through a surface marking on the existing outer surface. This eliminates the need for additional structural modifications that would disturb rotational balance, while still enabling optical measurement.
2Stability of the object's composition
If black paint is manually applied to the rotating body for optical measurement, then rotational balance is maintained better, but measurement accuracy decreases due to uneven application
Solution Approach 1:
The invention replaces the manual mechanical application process (painting) with a machining process that forms the marking through material removal or displacement. This substitution eliminates human error and uneven application, providing consistent and precise marking geometry that ensures accurate measurement while maintaining rotational balance.
Solution Approach 2:
The marking is formed on the outer surface before the rotating body is assembled into the final system. This preliminary formation ensures that the marking geometry is precise and consistent, and that any minor imbalances from the marking process can be addressed during standard balancing procedures before assembly.
3Measurement precision
If a marking is processed on the measurement surface to change light reflection direction, then measurement accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The invention uses conventional machining methods (such as milling, grinding, or turning) to form the marking on the outer surface, replacing complex surface treatment processes. These machining operations are standard in manufacturing and can be integrated into existing production lines, providing precise marking geometry without significantly increasing manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system accurately measures rotational speed while maintaining the rotational balance of the rotating body, reducing interference and ensuring consistent light reflection.
Implementation Method 1
an optical sensor disposed at a position facing a measurement surface being a portion of an outer surface of the rotating body, the optical sensor being configured to irradiate the measurement surface with measurement light and receive reflected light of the measurement light from the measurement surface
Implementation Method 2
The second measurement region includes a marking processed to reflect the reflected light, when the irradiation position is located in the second measurement region, in a direction different from a reflection direction of the reflected light, when the irradiation position is located in the first measurement region
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A measurement system according to an embodiment of the present disclosure includes: a rotating body; an optical sensor configured to irradiate a measurement surface of the rotating body with measurement light and receive reflected light of the measurement light from the measurement surface; and a measurement device configured to measure a rotational speed of the rotating body based on a change in a state of the reflected light reaching the optical sensor from the measurement surface. The measurement surface includes: a first measurement region configured to reflect the reflected light toward the optical sensor; and a second measurement region adjacent to the first measurement region in a circumferential direction of the rotational axis and configured to pass through an irradiation position of the measurement light on the measurement surface for each revolution of the rotating body about the rotational axis. The second measurement region includes a marking processed to reflect the reflected light, when the irradiation position is located in the second measurement region, in a direction different from a reflection direction of the reflected light, when the irradiation position is located in the first measurement region.