Acoustic Crankpin Surface Detection in Crankshaft Grinding
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Solution Overview
Problem
Existing grinding machines face challenges in accurately determining the location of crankshaft surfaces, which can introduce errors due to variables like crankshaft sag, flexure, and thermal variations, leading to inefficiencies and the need for thicker hardening material.
Innovation Solution
The implementation of an acoustic emission sensor in a grinding machine to detect contact between the grinding wheel and the crankshaft, allowing for precise determination of the grinding wheel and crankshaft surface positions, thereby reducing the thickness of hardening material required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical contact probes are used to locate crankshaft surfaces, then the measurement can be obtained, but the precision is insufficient and errors occur due to crankshaft sag, flexure, and thermal variations
Solution Approach 1:
The patent replaces the mechanical contact probe system with an acoustic emission detection system. The acoustic sensor detects the acoustic signal generated when the grinding wheel contacts the crankshaft surface, eliminating the need for physical contact probes that are susceptible to errors from crankshaft sag, flexure, and thermal variations. This substitution of mechanical detection with acoustic field detection resolves the precision and reliability issues.
Solution Approach 2:
The patent introduces acoustic emission signals as an intermediary to detect the contact between the grinding wheel and crankshaft surface. Instead of directly measuring the position through physical probes, the system uses acoustic signals generated at the contact point as a mediator to determine the precise location, thereby avoiding the limitations of direct mechanical measurement.
2Reliability
If thicker hardening material is applied to compensate for measurement errors, then the reliability of the crankshaft surface is improved, but the manufacturing time and material usage increase
Solution Approach 1:
By replacing mechanical contact measurement with acoustic emission detection, the system achieves superior measurement precision that eliminates the need to over-compensate with thicker hardening material. The accurate acoustic-based positioning allows for precise grinding that maintains crankshaft surface reliability while minimizing material usage and processing time.
Solution Approach 2:
The patent utilizes acoustic wave propagation (analogous to pneumatic/hydraulic principles in terms of wave-based detection) to detect contact points without mechanical interference. This wave-based detection method provides more accurate positioning information, enabling optimized hardening material application that improves reliability without sacrificing productivity.
3Measurement precision
If physical contact probes are used to detect crankshaft surfaces, then the device structure is simple, but the measurement precision is insufficient
Solution Approach 1:
The patent replaces simple mechanical contact probes with an acoustic emission detection system that uses acoustic sensors and signal processing electronics. While this increases device complexity, it dramatically improves measurement precision by detecting contact through acoustic signals, which are not affected by the mechanical limitations that plague contact probe systems.
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
This approach enhances the precision of crankshaft surface location determination, reduces the thickness of hardening material needed, and decreases the time spent applying hardening material, improving overall grinding efficiency and accuracy.
Implementation Method 1
an acoustic emission sensor coupled to the grinding machine, such that the grinding machine is configured to monitor an output signal from the acoustic emission sensor, move the grinding wheel into contact with the crankshaft at a first angular position, detect contact between the grinding wheel and the crankshaft based on the output signal
Data Source
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AI summary
A grinding machine including one or more grinding wheels has a workpiece holder that releasably holds a crankshaft and is configured to rotate the crankshaft about a longitudinal axis; a spindle assembly, that is moveable in at least two directions, including a spindle shaft and a grinding wheel attached to the spindle shaft; and an acoustic emission sensor coupled to the grinding machine, such that the grinding machine is configured to monitor an output signal from the acoustic emission sensor, move the grinding wheel into contact with the crankshaft at a first angular position, detect contact between the grinding wheel and the crankshaft based on the output signal, determine a position of the grinding wheel based on the detected contact between the grinding wheel and the crankshaft, move the grinding wheel away from the crankshaft, rotate the crankshaft a defined angular amount, move the grinding wheel into contact with the crankshaft at a second angular position, determine a position of the grinding wheel based on the detected contact between the grinding wheel and the crankshaft, and determine a position of a crankshaft surface.