Ball Screw Preload Degradation Detection via Vibration Analysis
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Solution Overview
Problem
Existing methods are inadequate for detecting preload degradation in ball screws before backlash occurs, which can lead to undesirable vibration and reduced precision and service life.
Innovation Solution
A method using a computer device connected to sensors that obtain and analyze vibration and inertial-force signals to assess preload degradation by comparing data to reference eigenvectors and assessment ranges, determining if preload has degraded through machine learning algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to determine backlash formation, then backlash detection is possible, but preload degradation cannot be detected before backlash occurs
Solution Approach 1:
The patent applies preliminary action by detecting preload degradation before backlash actually occurs. The system monitors vibration signals and calculates degradation degrees in advance, allowing preventive maintenance to be performed before the ball screw reaches a critical state with backlash, thus extending service life and maintaining precision.
Solution Approach 2:
The patent utilizes mechanical vibration by mounting sensors on the ball screw to detect vibration signals. The system analyzes these vibration signals to calculate preload degradation degrees, transforming the mechanical vibration state of the ball screw into detectable signal data that reveals degradation trends before backlash formation.
2Device complexity
If ball screw operates without preload monitoring, then device complexity is reduced, but undesirable vibration and precision loss occur
Solution Approach 1:
The patent replaces complex mechanical monitoring systems with a signal processing approach. Instead of using multiple sensors and complex mechanical measurement devices, the system uses vibration signal analysis and mathematical calculations (degradation degree computation) to monitor preload status, simplifying the overall system while effectively detecting degradation.
Solution Approach 2:
The patent introduces vibration signals as an intermediary to detect preload degradation. Rather than directly measuring preload force which would require complex sensors, the system uses vibration signals as an intermediate indicator that correlates with preload degradation, enabling indirect but effective monitoring.
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 early detection of preload degradation, preventing backlash and maintaining precision and extending the service life of ball screws.
Implementation Method 1
a first sensor (2) mounted on the nut (41), and adjacent to the return mechanism (43), that periodically transmits to the computer device (1) a vibration signal which is related to vibrations of the balls (44) in the return mechanism (43)
Data Source
AI summary
A method for assessing preload degradation of a ball screw is to be implemented by a computer device. The method includes: obtaining an entry of time-domain vibration data based on a vibration signal which is related to vibrations of balls of the ball screw; obtaining an entry of frequency-domain vibration derived data based on the time-domain vibration data; obtaining a vibration eigenvector based on the entry of frequency-domain vibration derived data; performing preload assessment based on the vibration eigenvector, reference vibration vectors and a preload assessment range to obtain a result of the preload assessment; and determining whether preload degradation has occurred on the ball screw based on the result of the preload assessment.