Actuator Fault Detection Sensor Housing Vibration Attenuation
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Solution Overview
Problem
Existing fault detection systems for actuators with both linear guide and ball screw units face challenges in accurately diagnosing faults using shared sensors, as the stronger vibrations from the ball screw unit overshadow those from the linear guide unit, making it difficult to detect faults in the linear guide unit.
Innovation Solution
A fault detection sensor-equipped actuator design that places a vibration, AE, or ultrasonic sensor inside a housing with a coupling between the screw shaft and motor shaft, allowing the sensor to detect vibrations and elastic waves propagating through the housing, which attenuates ball screw unit vibrations while allowing linear guide unit vibrations to be more effectively sensed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a shared sensor is used to detect faults in both linear guide unit and ball screw unit, then the number of sensors is reduced, but it becomes difficult to detect faults in the linear guide unit due to stronger vibrations from the ball screw unit
Solution Approach 1:
The housing serves as an intermediary structure that selectively transmits vibrations from both the linear guide unit and ball screw unit to the sensor. By positioning the sensor on the housing rather than directly on the components, the housing acts as a mediator that balances the vibration signals, allowing the sensor to detect faults in both units simultaneously without being overwhelmed by the stronger ball screw vibrations.
Solution Approach 2:
The sensor is positioned on the housing structure, transitioning from direct component monitoring to structural monitoring. This dimensional shift allows the sensor to capture vibration signals from multiple sources (linear guide unit and ball screw unit) through the housing's vibration propagation characteristics, enabling simultaneous fault detection of both units with a single sensor.
2Measurement precision
If sensors are attached to each of linear guide unit and ball screw unit, then fault detection capability is improved, but device complexity increases due to more sensors and wiring
Solution Approach 1:
The patent merges the fault detection function for both the linear guide unit and ball screw unit into a single sensor system. By placing one sensor on the housing, both units' vibration signals are combined and transmitted to the same detection point, eliminating the need for separate sensors and their associated wiring for each unit.
Solution Approach 2:
The housing serves a dual function: it provides structural support for the actuator components and simultaneously acts as a vibration transmission medium for fault detection. This multi-functionality allows the same structure to serve both mechanical and diagnostic purposes, reducing the need for additional dedicated fault detection components.
3Device complexity
If the sensor is placed inside the housing, then wiring is simplified, but the sensor must effectively distinguish vibrations from different sources
Solution Approach 1:
The housing acts as an intermediary that naturally separates and transmits vibration signals from different sources to the sensor. The structural pathways through which vibrations from the linear guide unit and ball screw unit propagate through the housing create distinguishable signal characteristics, allowing the sensor to differentiate between the two sources even though both signals reach the same detection point.
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 design enables a shared sensor to easily detect faults in both the linear guide and ball screw units by balancing the propagation of vibrations from both units, improving fault detection accuracy without hindering the actuator's movement or requiring additional wiring.
Implementation Method 1
the sensor includes a vibration sensor that detects vibration of the housing
Implementation Method 2
an AE (Acoustic Emission) sensor that detects an elastic wave propagating to the housing
Implementation Method 3
an ultrasonic sensor that detects ultrasound propagating to the housing
Data Source
AI summary
A fault detection sensor-equipped actuator is provided which can easily detect a fault in at least one of a linear guide unit and a ball screw unit, using a shared sensor. In an actuator (10) including a linear guide unit (4) that guides linear movement of a movable body (1) and a ball screw unit (7) that drives the movable body (1) in an axial direction of a screw shaft (6), a sensor (18) configured to detect a fault in the actuator (10) is placed in a housing (11) where a coupling (12) that couples the screw shaft (6) and a motor (14) for rotating the screw shaft (6) is housed.