Bolting Torque Selection Using Fracture Torque and Fastening Angle
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Solution Overview
Problem
Existing methods for determining bolting torque in battery pack assembly are inaccurate and inconsistent, leading to variations in fastening force and quality due to worker experience and varying conditions, resulting in potential loose or excessive fastening.
Innovation Solution
A method involving the determination of an effective fastening torque zone based on sample fracture torque, with experimental torques selected within this zone, and measuring bolt fastening angles to accurately determine the bolting torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the bolting torque is arbitrarily selected within a certain torque zone based on worker experience, then the selection flexibility is increased, but the bolting quality uniformity deteriorates due to torque deviations increasing with higher fracture torque
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 the effective fastening torque zone as a specific percentage range (e.g., 60-80%) of the measured fracture torque, the invention transforms subjective parameter selection into objective parameter determination, thereby improving bolting quality uniformity while maintaining operational flexibility within the scientifically-determined zone.
Solution Approach 2:
The invention implements a feedback mechanism where the fracture torque is first measured through testing, then this measured value feeds back to determine the appropriate effective fastening torque zone. This closed-loop approach ensures that the bolting torque selection is based on actual material properties and testing results rather than arbitrary worker experience, resolving the contradiction between selection flexibility and quality uniformity.
2Device complexity
If the bolting torque is empirically determined based on fracture torque, then the determination process is simplified, but the accuracy deteriorates because workers cannot accurately consider varying conditions such as dimensional precision, surface roughness, and lubrication state
Solution Approach 1:
The patent introduces an intermediary concept called the 'effective fastening torque zone' that acts as a mediator between the complex varying conditions (dimensional precision, surface roughness, lubrication state) and the final bolting torque determination. Instead of requiring workers to directly assess and balance multiple varying conditions, the invention provides a standardized zone based on fracture torque that automatically accounts for these conditions, thereby maintaining process simplicity while improving accuracy.
3Ease of operation
If the fastening torque zone is set too wide to provide selection flexibility, then the ease of operation is improved, but the measurement precision of bolting torque deteriorates due to increased torque deviations
Solution Approach 1:
The patent dynamically adjusts the torque zone parameters based on the measured fracture torque value. Rather than using a fixed wide zone that compromises precision, the invention calculates the effective fastening torque zone as a specific percentage range of the actual fracture torque, thereby optimizing the balance between selection flexibility and measurement precision for each specific application.
Data Source
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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 which are to be bolted, a sample fracture torque acquisition process of measuring and acquiring a sample fracture torque at which at least one of the samples of the object and the bolt is fractured when the samples of the object and the bolt are bolted, an effective fastening torque zone determination process of determining an effective fastening torque zone, in which fastening is performed without fracture, on the basis of the sample fracture torque, an experimental torque selection process of selecting a plurality of experimental torques within the effective fastening torque zone, 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, which is to be used for bolting of the object and the bolt among the plurality of experimental torques, on the basis of the plurality of measured bolt fastening angles. In the bolting fastening angle measurement process, 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. The bolting torque determination method may accurately determine the bolting torque to enhance bolting quality.