Pneumatic Tool Torque Control via Dynamic Air Pressure Regulation
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Solution Overview
Problem
High-speed pneumatic impact and impulse tools face challenges in controlling torque accurately, leading to tool overrun and excessive heating during the tightening of critical bolts, making them unsuitable for precise applications.
Innovation Solution
Dynamically controlling the output power of pneumatic tools using an electronically controlled air pressure regulator to adjust the tightening rate and minimize overrun, while reducing rundown speed to prevent heating, allowing for precise stopping at specified torque levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed pneumatic impact tools are used to tighten bolts quickly, then productivity is improved, but manufacturing precision deteriorates due to tool overrun and inability to stop precisely at specified torque
Solution Approach 1:
The system continuously monitors fastener load during tightening using ultrasonic transducers and feeds this information back to the control system. Based on the feedback, the controller dynamically adjusts air pressure to the pneumatic tool, enabling precise control of the tightening process and accurate stopping at the specified load despite the high-speed impacting action
Solution Approach 2:
The system dynamically adjusts the air pressure supplied to the pneumatic impact tool during the tightening cycle based on real-time load measurements. This dynamic control allows the tool to operate at high speed while automatically modulating power delivery to achieve precise stopping at the target torque, resolving the contradiction between speed and precision
2Productivity
If pneumatic tools are sized to minimize assembly time, then productivity is improved, but object-generated harmful factors worsen due to excessive tool overrun exceeding specified loads
Solution Approach 1:
The control system continuously monitors fastener load and provides feedback to dynamically adjust air pressure, enabling the tool to stop precisely at the specified load rather than continuing to overrun. This feedback control eliminates excessive tool overrun while maintaining high-speed operation for quick assembly
Solution Approach 2:
The system changes the air pressure parameter dynamically during the tightening cycle based on real-time load conditions. By adjusting this key parameter, the system optimizes the balance between assembly speed and preventing tool overrun, allowing fast assembly without exceeding specified loads
3Productivity
If rundown speed is high above 6000 rpm, then productivity is improved, but object-affected harmful factors worsen due to excessive localized heating in fastener threads
Solution Approach 1:
The system dynamically adjusts air pressure during rundown based on real-time load measurements from ultrasonic transducers. This dynamic control allows the tool to maintain high speed for productivity while automatically reducing power delivery during rundown to prevent excessive localized heating in the fastener threads
Solution Approach 2:
The system modifies the air pressure parameter during different phases of tightening, particularly reducing it during rundown to minimize heating effects. This parameter adjustment maintains high productivity while protecting the fastener from thermal damage
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
Enables the use of high-speed pneumatic tools for precise torque control, reducing tool overrun and heating effects, thus making them suitable for critical bolt tightening applications.
Implementation Method 1
making load measurements in the fastener (1) during tightening using the ultrasonic transducer (2)
Implementation Method 2
an electronically controlled air pressure regulator (5) associated with the supply line (6) which delivers pressurized air to the impact wrench (3) to dynamically control the air pressure supplied to the impact wrench (3) during tightening
Data Source
AI summary
Pneumatic tightening tools can be used for high speed assembly of critical bolts to precise loads by dynamically controlling the output power of the pneumatic tool during a tightening cycle using an electronically controlled air pressure regulator (5) to reduce the tightening rate, or the load increase per impact for impact or impulse tools, to enable the tool to be stopped precisely at a specified stopping load or torque. For prevailing torque fasteners, the output power of the pneumatic tool is dynamically controlled to minimize the speed of rotation during rundown, to minimize the heating effects associated with such torque fasteners, and to then increase the power from the tool, as required, to provide the torque to reach the specified stopping load or torque. The maximum air pressure supplied to the pneumatic tool (3) can be limited, depending on the expected torque required to tighten the fastener to the specified load or torque.