Adaptive Bolt Tightening Angle Control for Axial Force Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The conventional torque+angle method for bolt tightening leads to unstable bolt axial force due to varying torque gradients in initial and late tightening stages, resulting in reduced effective axial force on fastened members, especially when elastic deforming members are involved.
Innovation Solution
A method and apparatus that modify the torque+angle approach by introducing a total turning angle comprising an initial-set angle and corrective additional-turning angles, where the corrective additional-turning angles compensate for the difference in bolt turning angles and torque gradients between initial and late stages, ensuring consistent axial force across varying torque properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional torque+angle method is applied to bolts with bent torque properties (initial stage with smaller torque gradient, late stage with larger torque gradient), then the bolt tightening process can be completed, but the bolt axial force becomes unstable and scatters due to varying torque gradients
Solution Approach 1:
The patent applies dynamics by making the turning angle control adaptive rather than fixed. The system dynamically adjusts the turning angle based on real-time torque gradient detection, transitioning from a static predetermined angle to a dynamic corrected angle that adapts to the actual bolt tightening characteristics, thereby resolving the contradiction between efficiency and precision
Solution Approach 2:
The patent implements feedback by continuously monitoring the torque gradient during the tightening process and using this information to calculate and apply a corrective turning angle. This closed-loop feedback mechanism allows the system to compensate for deviations from the expected torque properties, ensuring consistent bolt axial force while maintaining tightening efficiency
2Reliability
If elastic deforming members are used between fastened members, then the initial bolt tightening stage consumes part of the bolt axial force for eliminating (crushing) the elastic deforming member, but this reduces the effective bolt axial force acting on the fastened members
Solution Approach 1:
The patent applies preliminary action by detecting the torque gradient characteristics during the initial tightening stage (which includes the elastic deforming member elimination phase) and using this information to pre-calculate the corrective turning angle before the final tightening phase. This allows the system to anticipate and compensate for the force consumption by the elastic deforming member, ensuring sufficient effective axial force reaches the fastened members
Solution Approach 2:
The patent changes the turning angle parameter dynamically based on detected torque gradient variations. By adjusting the turning angle parameter in response to the elastic deforming member's influence on torque characteristics, the system compensates for the axial force consumption and maintains the required effective force on the fastened members while preserving the reliability benefits of using elastic deforming members
Data Source
AI summary
After it is tightened with a snug torque TA, a bolt is tuned by a total turning angle θS equivalent to the sum of an initial-set turning angle θA and a corrective additional-turning angle (θB+θC). The corrective additional-turning angle (θB+θC) is the sum of a first corrective additional-turning angle θB and a second corrective additional-turning angle θC, the first corrective additional-turning angle θB being to compensate for a situation where a bolt turning angle θ22 corresponding to the snug torque θA on an extension line of the bolt tightening torque properties C2 in a late tightening stage II is different from a bolt turning angle θ11 corresponding to the actual snug torque TA, the second corrective additional-turning angle θC being to compensate for a decrease of an effective bolt axial force that is caused by an existence of the initial tightening stage I.