Optical Grating Strip for TBM Disc Cutter Monitoring
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Solution Overview
Problem
Existing methods for monitoring the performance of tunnel boring machine (TBM) disc cutters are inaccurate due to magnetic field interference, deformation, and temperature changes, failing to measure rotating speed, direction, acceleration, and vibration frequency effectively.
Innovation Solution
A performance monitoring system using an optical transceiver, temperature sensor, and ring-shaped grating strip embedded within the disc cutter, which rotates to chop light beams and generate pulsed signals for determining rotating speed, direction, acceleration, and vibration frequency without altering the disc cutter's mechanical structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnets are inlaid into the disc cutter for performance detection, then the rotating speed can be measured, but the measurement accuracy is reduced due to rock fragment damage, magnetic field shielding, magnet deformation, and temperature changes
Solution Approach 1:
The patent replaces the magnetic field-based detection system with an optical detection system. Instead of using magnets that are subject to mechanical damage and temperature effects, the invention uses an optical grating strip that rotates with the disc cutter and an optical detector to measure rotation parameters. This substitution of mechanical/magnetic components with optical components resolves the reliability and accuracy problems associated with magnet degradation.
Solution Approach 2:
The patent introduces an optical grating strip as an intermediary element between the disc cutter and the detection system. The grating strip rotates with the disc cutter but is detected optically without physical contact between the detection system and the rotating cutter, eliminating direct mechanical interference and magnetic field issues while maintaining measurement capability.
2Loss of information
If magnets are used for detection, then rotation speed can be monitored, but rotating direction and acceleration cannot be measured
Solution Approach 1:
The optical detection system using the rotating grating strip and optical detector can capture complete rotation information including direction and acceleration by analyzing the temporal and spatial characteristics of the optical signals, whereas magnetic detectors cannot provide this comprehensive information.
Solution Approach 2:
The optical detection system based on the grating strip serves multiple functions simultaneously: it measures rotating speed, determines rotation direction, and calculates rotating acceleration, making the detection system universal and multi-functional compared to the limited magnetic detection capability.
3Loss of information
If magnets are inlaid in the disc cutter, then performance monitoring is possible, but the mechanical structure of the disc cutter must be modified
Solution Approach 1:
The patent replaces the need for mechanical modification of the disc cutter by using an optical grating strip that can be mounted on the existing disc cutter structure without altering its mechanical integrity. The optical detection system externally monitors the cutter performance without requiring embedded components that would compromise the cutter's structural strength.
Solution Approach 2:
The optical grating strip functions as a thin, flexible measurement component that can be attached to the disc cutter surface without significantly affecting its mechanical properties. This thin-film approach allows performance monitoring while preserving the original structural integrity and manufacturing simplicity of the disc cutter.
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 provides accurate, real-time monitoring of disc cutter performance parameters, preventing damage and allowing timely replacement, while avoiding external interference and mechanical stress.
Implementation Method 1
the grating strip is driven to rotate by the isolation boss to chop a light beam emitted from the transmitting optical fibers embedded in the T-shaped extension support based on relative motion relationship between the bearing spacer and the isolation boss
Implementation Method 2
the light beam is reflected back to the receiving optical fibers by non-hollowed portion of the grating strip and then transmitted to the optical transceiver at exterior, to acquire a pulsed signal with a positioning feature
Implementation Method 3
A performance monitoring system for a disc cutter of the TBM includes an optical transceiver, temperature sensor, disc cutter body, shaft assembly and isolation boss
Data Source
AI summary
A performance monitoring system for a disc cutter of a tunnel boring machine (TBM) is provided, and includes a disc cutter body, a shaft assembly and an isolation boss; the shaft assembly includes a shaft main body and a bearing spacer located on the shaft main body; a rotating mechanism is arranged in a space between the isolation boss and the bearing spacer; the rotating mechanism includes a rotator and a T-shaped extension support located between the bearing spacer and the rotator; bearing retainers of roller bearings are arranged on two sides of the T-shaped extension support; a ring-shaped grating strip is arranged on one side of the rotator close to the T-shaped extension support; a connecting component is arranged on one side of the rotator away from a rotating bearing; and a sealing assembly is arranged between the T-shaped extension support and the rotator.