Compressed Air Tool Speed Control With Self-Powered Voltage Regulation
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Solution Overview
Problem
Compressed air-driven tools in the metalworking industry face challenges in maintaining consistent speed under varying loads due to reliance on variable voltage generated by the motor shaft, leading to unreliable speed control and potential power failures.
Innovation Solution
A compressed air-driven tool design that uses a voltage regulator to generate a constant output voltage for a microcontroller, allowing independent control of the electromagnetic control element to maintain selected speed regardless of load, with the internally generated voltage only used for the microcontroller and inlet valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a generator on the motor shaft is used to control speed, then the tool does not need an external power source, but the speed control becomes insufficient to maintain constant speed under changing loads
Solution Approach 1:
The patent introduces a voltage regulator as an intermediary component between the generator and the microcontroller. The voltage regulator stabilizes the variable voltage from the generator into a constant voltage, enabling reliable microcontroller operation and accurate speed control without external power sources.
Solution Approach 2:
The patent implements a feedback control system where the microcontroller continuously monitors motor speed and adjusts the electromagnetic actuator accordingly. This closed-loop feedback mechanism maintains constant speed despite varying loads, resolving the unreliability of the generator-based control system.
2Ease of operation
If electromagnetic actuator control is used, then speed can be controlled, but the control depends on variable voltage and cannot maintain set speed under varying loads
Solution Approach 1:
The microcontroller continuously measures the actual motor speed and compares it with the desired set speed. Based on this feedback, the microcontroller adjusts the electromagnetic actuator to maintain the set speed, ensuring precise speed control under varying loads.
Solution Approach 2:
The system dynamically changes the control parameters by adjusting the electromagnetic actuator's operation based on real-time speed measurements. This parameter adjustment allows the system to maintain optimal performance across different load conditions.
3Ease of operation
If centrifugal governors are used to control speed, then the air supply can be throttled, but the reliability required today and keeping the speed constant with changing work processes and conditions cannot be achieved
Solution Approach 1:
The patent replaces the mechanical centrifugal governor system with an electronic control system comprising a microcontroller, voltage regulator, and electromagnetic actuator. This substitution enables more reliable and precise speed control that can adapt to changing work conditions, overcoming the limitations of mechanical governors.
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 precise speed control and immediate reduction to a harmless minimum speed in case of power failure, ensuring reliable operation and maintaining set speed under changing loads.
Implementation Method 1
A generator (43) generates a corresponding variable output voltage as a function of the speed of the shaft (49)
Implementation Method 2
A voltage regulator (57) generates a constant output voltage for feeding a microcontroller (37), independently of the current variable speed of the shaft (49)
Implementation Method 3
the electromagnetic control element can be used to control the air passage at the inlet valve
Data Source
Figure 1a
Figure 1b~1c
Figure 2a
AI summary
The invention relates to a compressed air-driven tool having an electromagnetically operated control element (27) for controlling a pneumatic control circuit in order to maintain a load-independent torque at a constant rotational speed. The tool comprises a principal valve (5), which arranged in a drive housing (1) in a manner displaceable by the supplied compressed air against the force of a helical spring (13), and a generator (43), which is mounted on the shaft (49) of a turbine wheel (51). The rotational speed of the shaft (49) is measured with a speed sensor (75) and the supply of compressed air to the principal valve (5) is controlled in the event of a drop in rotational speed as a consequence of a load.