Bolt Clamping Force Transducer for Precision Tightening
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Solution Overview
Problem
Current bolt tightening methods rely on torque control, which only converts about 10% of torque into clamping force, making it difficult to achieve uniform and precise clamping forces in high-precision assembly operations, especially in pressurized containers and engine cylinders, due to factors like material hardness and surface conditions, leading to quality risks and uncertainties.
Innovation Solution
A clamping force transducer that directly senses and controls the clamping force on a bolted joint by integrating a force sensing module with a torque tool, allowing for real-time data transmission and precise control of the clamping force, reducing reliance on expensive ultrasonic and axial force detection technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional torque control methods are used to tighten bolts, then torque can be controlled with 5% accuracy, but the residual clamping force varies by up to 50% due to friction and material variations
Solution Approach 1:
The patent replaces conventional torque-based mechanical control with a direct clamping force sensing system. A force sensing module (strain gauges or piezoelectric sensors) is integrated into the torque tool to directly measure the clamping force generated, substituting indirect torque control with direct force measurement. This allows real-time monitoring and control of actual clamping force rather than relying on torque-to-force conversion ratios that vary with friction conditions.
Solution Approach 2:
The patent implements a feedback control system where the force sensing module continuously monitors clamping force during tightening operations. The measured force data is fed back to a control device that can adjust tightening parameters in real-time to achieve target clamping force values. This closed-loop feedback mechanism enables precise control of clamping force despite variations in friction, material properties, and surface conditions.
2Measurement precision
If expensive ultrasonic sensing technology or strain sensing components are used to directly measure clamping force, then measurement precision improves, but manufacturing cost and installation complexity increase significantly
Solution Approach 1:
The patent designs a force sensing module that can be integrated into conventional torque tools, making the existing tool serve dual purposes: torque application and direct force measurement. The module uses standard strain gauge technology or piezoelectric sensors that are relatively inexpensive and easy to install compared to ultrasonic sensing systems. This universal integration approach allows conventional torque tools to perform precise clamping force measurement without requiring specialized expensive equipment.
Solution Approach 2:
The patent employs inexpensive strain gauge-based force sensing components that can be easily manufactured and installed. These sensing elements use standard electrical resistance strain measurement technology rather than expensive ultrasonic or specialized axial force sensors. The module can be attached to the torque tool in a relatively simple manner, reducing both manufacturing and installation costs while achieving sufficient measurement precision for industrial applications.
3Measurement precision
If strain sensing components are adhered to sensing bolts to detect clamping force, then direct force measurement is achieved, but the bolt can only be tightened with an open-end wrench reducing ease of use and efficiency
Solution Approach 1:
The patent merges the force sensing functionality directly into the torque tool itself rather than requiring separate sensing bolts. The force sensing module is integrated into the tool's structure, combining torque application and force measurement functions in a single device. This eliminates the need for specialized sensing bolts that require open-end wrenches, allowing standard socket operations to continue while achieving direct clamping force measurement.
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
Enhances tightening precision, reduces costs, and increases industrial efficiency by enabling direct control of clamping forces, ensuring consistent and desirable clamping forces on bolted joints, thus addressing the limitations of conventional torque control methods.
Implementation Method 1
the force sensing component is adhered to the bottom of the annular recess to sense the strain value of the sensing ring body axially loaded and electrically connected to a signal processing module
Data Source
AI summary
A bolt clamping force transducer for a bolt tightening operation is introduced to tighten a bolted joint by driving a torque rotating shaft in a clamping force transducer, such that a helical mechanism at one end of the torque rotating shaft generates an axial force for pressing a force sensing module and thus generates a strain value thereof. A socket is driven by the other end of the torque rotating shaft, thereby generating a clamping force under which the bolted joint of a specific specification is tightened. A parameter relation between the strain value and the clamping force is calibrated with a standard axial force gauge to facilitate calculation and control of the clamping force during the tightening process where the bolted joint fitted to any torque tool is sensed to control the precision of the clamping force being exerted on the bolted joint, thereby enhancing the quality thereof.