Electric Actuator Fail-Safe Operation via Differential Energy Storage
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Solution Overview
Problem
Existing electric actuators for industrial applications face challenges in efficiently transitioning to a fail-safe position upon power loss, as current solutions are often complex, voluminous, and susceptible to failure.
Innovation Solution
An electric actuator design incorporating a first driving source, a second energy-storing driving source, a differential, a switching controller, a mechanical stop, and brakes to manage energy transfer and positioning through multiple pathways, ensuring the actuator moves to a fail-safe position without external power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transmission and cam-clutch system is used to transmit potential energy stored in a spring to achieve fail-safe actuation, then the actuator can move to a pre-determined position upon power loss, but the system occupies high volume, requires high torque, and becomes complex and susceptible to failure
Solution Approach 1:
The transmission system is segmented into multiple independent pathways: a first pathway for normal powered operation, a second pathway for fail-safe spring-driven operation, and a third pathway for energy storage. This segmentation allows each pathway to be optimized independently and reduces the complexity of any single pathway while maintaining overall system reliability.
Solution Approach 2:
The differential mechanism serves multiple functions: it acts as a torque amplifier during normal operation, functions as an energy storage mechanism by allowing the spring to wind during powered operation, and enables fail-safe actuation when power is lost. This multi-functionality eliminates the need for separate dedicated components for each operation mode, reducing overall system complexity.
2Reliability
If a transmission and cam-clutch system is used with a spring for fail-safe actuation, then the actuator can achieve desired output positioning, but the system occupies high volume
Solution Approach 1:
The spring mechanism is merged with the differential and transmission components rather than being a separate external component. The spring is positioned within the existing actuator housing and integrates with the differential mechanism, allowing fail-safe functionality without adding external volume to the actuator assembly.
Solution Approach 2:
The spring is nested within the differential mechanism, with the spring shaft passing through the differential housing. The energy storage pathway is nested within the existing transmission components, allowing the spring to wind and store energy without requiring additional external space, thus maintaining compact actuator dimensions.
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 effectively and reliably positions the actuator to a fail-safe state upon power loss, reducing complexity and susceptibility to failure while maintaining operational efficiency.
Implementation Method 1
A differential coupled to the first driving source and the second driving source through a third pathway created by the transmission is used to store energy from the first driving source in the second driving source
Implementation Method 2
a brake coupled to the second driving source through the transmission, the brake being engaged to establish the first pathway through the transmission between the first driving source and the output
Implementation Method 3
a mechanical stop coupled to the output through the transmission, and the mechanical stop being engaged to restrict the output from rotating beyond the fail-safe position
Data Source
AI summary
Aspects of the disclosure provide an electric actuator including a fail-safe mode of operation. The electric actuator includes a mechanical stop coupled to the output through the transmission, and a brake coupled to the second driving source through the transmission, the brake being engaged to establish the first pathway through the transmission between the first driving source and the output, the brake being disengaged to establish the second pathway through the transmission between the second driving source and the output, and the mechanical stop being engaged to restrict the output from rotating beyond the fail-safe position and the brake being disengaged to establish the third pathway through the transmission between the first driving source and the second driving source.