Electro-Hydrostatic Actuator Layout for High Force at Low Power
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Solution Overview
Problem
Traditional electro-hydrostatic actuators are large in size and have lower force output compared to their size, necessitating a smaller, more efficient actuator that can operate under low electrical power levels to produce high actuation forces.
Innovation Solution
An electro-hydrostatic actuator assembly with a single acting cylinder, accumulator, and solenoid with embedded magnets that pulse to pump oil through pistons and check valves, utilizing silicone oil to maintain viscosity over a wide temperature range and consuming low power when static.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional electro-hydrostatic actuators are used, then they provide sufficient actuation force, but they are large in size and consume high power
Solution Approach 1:
The solenoid assembly is nested within the cylinder body, with the core tube extending through the longitudinal axis and the armature positioned between the ferromagnetic end sections. The magnets are disposed radially outside the core tube, creating a compact nested arrangement that reduces overall actuator size while maintaining force output
Solution Approach 2:
The magnets are arranged radially outside the core tube rather than linearly, utilizing radial space to reduce the longitudinal dimension of the actuator. This dimensional reorganization allows the same force output in a more compact form factor
2Force
If traditional electro-hydrostatic actuators are used, then they provide sufficient actuation force, but they consume high electrical power
Solution Approach 1:
The solenoid assembly operates by pulsing the armature to pump fluid through the system, rather than maintaining continuous operation. The accumulator stores pressurized fluid and releases it periodically, allowing the solenoid to consume power only during pulsing cycles rather than continuously
Solution Approach 2:
The accumulator maintains fluid under pressure and urges fluid through the passageways without requiring continuous electrical power. The system uses its own stored energy (pressurized fluid in the accumulator) to sustain operation between power pulses, reducing overall electrical power consumption
3Use of energy by moving object
If the actuator operates under low electrical power levels, then power consumption is reduced, but maintaining performance across varying temperatures becomes challenging
Solution Approach 1:
The system uses silicone oil as the hydraulic fluid, which has been selected for its stable viscosity characteristics across a wide temperature range. This parameter selection (fluid type) allows the actuator to maintain performance consistency from -40°F to 200°F while operating on low electrical power
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
The actuator achieves high actuation forces with reduced size and power consumption, maintaining performance across varying temperatures and providing feedback through a position sensor.
Implementation Method 1
a solenoid assembly comprising a core tube, an armature, a first magnet, a second magnet, and an excitation coil... the excitation coil located radially outward from the first and second magnets
Implementation Method 2
the first magnet and the second magnet disposed radially outside the core tube... the core tube having a first ferromagnetic end section and a spaced apart second ferromagnetic end section
Implementation Method 3
an accumulator fluidly connected to the plurality of passageways, the accumulator operable to maintain a fluid under pressure and to urge the fluid through the plurality of passageways
Data Source
AI summary
Embodiments of the present disclosure provide a method and apparatus having an actuator assembly. An exemplary actuator assembly includes a cylinder body having a longitudinal axis and a plurality of passageways, and an accumulator fluidly connected to the plurality of passageways. The exemplary actuator assembly also includes a solenoid assembly comprising a core tube, an armature, a first magnet, a second magnet, and an excitation coil, the core tube extending through the longitudinal axis, the core tube having a first ferromagnetic end section and a spaced apart second ferromagnetic end section.