Bolting Torque Selection Using Fracture Torque and Angle Data
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Solution Overview
Problem
Existing methods for determining bolting torque in battery pack assembly are inaccurate, leading to inconsistent bolting quality due to reliance on worker experience and failure to account for material deviations and varying conditions such as dimensional precision, surface roughness, and lubrication state.
Innovation Solution
A method involving sample preparation, fracture torque measurement, determination of an effective fastening torque zone, experimental torque selection, test fastening with angle measurement, and sorting of bolt fastening angles to determine the optimal bolting torque, ensuring accurate and consistent fastening within the effective torque zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bolting torque is arbitrarily selected within a certain torque zone based on worker experience, then the bolting process can be completed, but torque deviations increase and bolting quality becomes inconsistent
Solution Approach 1:
The patent changes the parameter selection approach from arbitrary worker experience to a systematic method based on fracture torque measurements. By establishing an effective fastening torque zone as a percentage range of the measured fracture torque, the patent transforms subjective parameter selection into objective, data-driven parameter determination, thereby reducing torque deviations and improving bolting quality consistency
Solution Approach 2:
The patent replaces the mechanical judgment system (worker experience) with a measurement and calculation system. By using torque wrenches to measure fracture torque and then calculating the effective fastening torque zone through systematic formulas, the patent substitutes empirical mechanical judgment with precise measurement and computational determination, eliminating human variability in torque selection
2Strength
If bolting torque is increased to ensure fastening force, then fastening strength improves, but risk of fracture increases
Solution Approach 1:
The patent performs preliminary measurement of fracture torque before actual bolting operations. By conducting fracture torque tests on sample bolts and objects first, then using these measurement results to calculate the effective fastening torque zone, the patent enables advance planning of safe torque values that ensure adequate fastening strength while preventing fracture during the actual bolting process
Solution Approach 2:
The patent establishes a feedback loop where fracture torque measurements inform the selection of safe working torque values. By measuring the actual fracture torque of the specific bolt and object combination, then using this feedback to determine the effective fastening torque zone (typically 60-80% of fracture torque), the patent ensures that the applied fastening force is optimized to be sufficiently strong while maintaining a safety margin against fracture
3Device complexity
If empirical bolting torque selection is used, then the process is simple, but fastening quality becomes non-uniform due to varying conditions
Solution Approach 1:
The patent introduces systematic parameter determination based on actual measurements rather than fixed empirical values. By calculating the effective fastening torque zone as a dynamic range based on measured fracture torque, the patent adapts the bolting parameters to specific bolt-object combinations, ensuring uniform fastening quality across varying conditions while maintaining process efficiency through standardized measurement and calculation procedures
Data Source
AI summary
Disclosed is a bolting torque determination method which includes a preparation process of preparing samples of an object and samples of a bolt, a sample fracture torque acquisition process of measuring and acquiring a sample fracture torque, an effective fastening torque zone determination process of determining an effective fastening torque zone, in which fastening is performed without fracture, a bolt fastening angle measurement process of performing test fastening on the samples according to each of the plurality of selected experimental torques and measuring bolt fastening angles, and a bolting torque determination process of determining a bolting torque, whereby a rotation angle of each of the sample bolts is measured from a predetermined reference point of time to a point of time when the test fastening is finished.