Aero-Engine Rotor Bolt Tightening With Ultrasonic Preload Feedback
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Solution Overview
Problem
The assembly quality of aero-engine rotors is compromised by manual bolt tightening methods, leading to low efficiency, high labor intensity, and significant preload deviations, which affect the performance of the engine.
Innovation Solution
An automatic tightening device with real-time preload feedback control, utilizing a three-closed-loop vector control and Fuzzy PID controller, combined with an ultrasonic preload measurement system, to ensure precise and efficient bolt tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual mechanical tooling or low-automation devices are used for bolt tightening, then device complexity is reduced, but productivity and manufacturing precision deteriorate
Solution Approach 1:
The patent replaces manual mechanical tightening tools with an automated tightening device that uses a motor-driven tightening mechanism. The device incorporates a motor, transmission mechanism, and tightening tool to automatically perform bolt tightening operations, eliminating manual intervention and significantly improving assembly efficiency while maintaining manageable device complexity through modular design.
Solution Approach 2:
The patent implements a closed-loop feedback control system that uses ultrasonic sensors to detect bolt preload in real-time during tightening. The detected preload information is fed back to the control system, which adjusts the motor speed and tightening force dynamically to achieve precise preload control, thereby improving manufacturing precision without requiring overly complex mechanical structures.
2Device complexity
If manual torque method is used for bolt tightening, then device complexity is reduced, but manufacturing precision deteriorates due to large preload deviation
Solution Approach 1:
The patent replaces the simple mechanical torque wrench with an automated tightening system that integrates a motor, transmission mechanism, and ultrasonic detection system. This substitution enables precise control of bolt preload through electronic control and real-time feedback, achieving consistent preload values while keeping the control system architecture modular and manageable in complexity.
Solution Approach 2:
The patent implements a closed-loop feedback control system that uses ultrasonic sensors to detect bolt preload in real-time during tightening. The detected preload information is fed back to the control system, which adjusts the motor speed and tightening force dynamically to achieve precise preload control, thereby improving manufacturing precision without requiring overly complex mechanical structures.
Solution Approach 3:
The patent dynamically adjusts tightening parameters such as motor speed, torque, and tightening sequence based on real-time feedback from ultrasonic preload detection. By changing these parameters adaptively during the tightening process, the system achieves consistent preload values across all bolts while avoiding the need for excessively complex fixed mechanical control mechanisms.
3Productivity
If automated tightening device is implemented, then productivity and manufacturing precision are improved, but device complexity increases
Solution Approach 1:
The patent divides the automated tightening device into modular functional components: a motor module, transmission mechanism, tightening tool module, ultrasonic detection module, and control system. Each module performs a specific function and can be independently designed, manufactured, and maintained, which improves overall productivity while managing device complexity through modular architecture.
Solution Approach 2:
The patent designs the automated tightening device with multi-functional capabilities, including automated positioning, tightening execution, real-time preload detection, and adaptive control. The ultrasonic sensor system serves multiple purposes: detecting preload, monitoring tightening progress, and providing feedback for control adjustments, thereby improving productivity without proportionally increasing device complexity.
4Measurement precision
If ultrasonic echo is used only for preload calibration, then measurement precision is improved, but manufacturing precision deteriorates due to lack of closed-loop control
Solution Approach 1:
The patent transforms the ultrasonic preload detection from a mere calibration tool into the core of a closed-loop feedback control system. The ultrasonic sensor continuously monitors bolt preload during tightening, and the control system uses this real-time feedback to dynamically adjust motor speed and tightening force, ensuring precise preload control and eliminating the large deviations associated with open-loop torque methods.
Solution Approach 2:
The patent replaces the traditional open-loop torque control mechanism with a closed-loop control system that uses ultrasonic detection for real-time preload monitoring. This substitution enables precise mechanical control through electronic feedback, achieving consistent preload values while maintaining a manageable control system architecture through modular design.
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 device effectively reduces preload deviations and ensures consistent tightening, enhancing assembly quality and efficiency in complex rotor structures.
Implementation Method 1
an echo time T0 of the bolt before stretching and an echo time T1 of the bolt after stretching under the tensile force F are measured by an ultrasonic echo method
Data Source
AI summary
The present invention belongs to the field of tightening control methods and automatic tightening technology, and discloses a tightening control method and automatic tightening device for an aero-engine rotor based on bolt preload feedback. The automatic tightening device is based on a main body structure and is provided with a rotary table structure, a spherical guide structure and a skid platform structure to achieve the degree of freedom of movement of the automatic tightening device for an aero-engine rotor within an inner cavity space of the rotor, enabling the tightening structure to be fed and withdrawn; in addition, a preload detection structure is provided, which relies on an ultrasonic preload measurement system to measure a real-time preload of a bolt during a tightening process and transmit the value of the preload to a tightening gun to achieve a tightening method for preload feedback control.