Electro Hydrostatic Actuator Center Axis Alignment
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Solution Overview
Problem
The existing electro hydrostatic actuator (EHA) systems face a significant weight unbalance issue due to the displacement of the hydraulic pump and electric motor from the center axis, leading to increased weight and vibration challenges when used in aircraft applications.
Innovation Solution
The EHA system configures the hydraulic pump and electric motor to surround the actuator body along the center axis, ensuring the center of gravity is aligned with the actuator, reducing weight unbalance and allowing for improved vibration performance without increasing the overall weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the hydraulic pump and electric motor are placed at the side of the extendable hydraulic linear actuator and fixed through the attachment flange, then the EHA can be assembled, but the center of gravity is greatly displaced from the center axis causing weight unbalance
Solution Approach 1:
The patent transitions from a side-mounted configuration (radial direction) to a longitudinal arrangement along the center axis (axial direction). The hydraulic pump and electric motor are positioned sequentially along the center axis of the actuator body, with the pump at one end and the motor at the other end or intermediate position, transforming the spatial arrangement from lateral to axial to achieve center of gravity alignment.
2Reliability
If the size or thickness of the attachment flange is increased to satisfy vibration requirements, then the vibration requirements are met, but the weight of the EHA system increases
Solution Approach 1:
Instead of increasing the attachment flange size to address vibration issues, the patent inverts the approach by addressing the root cause: the lateral displacement of components. By repositioning the hydraulic pump and electric motor along the center axis, the design eliminates the need for oversized attachment flanges, thereby satisfying vibration requirements without additional weight.
3Area of stationary object
If the hydraulic pump and electric motor are arranged in parallel at the side, then the assembly is compact laterally, but the center of gravity displacement causes vibration problems
Solution Approach 1:
The patent redistributes components along the axial dimension rather than confining them to the radial plane. The hydraulic pump and electric motor are arranged sequentially along the center axis, utilizing the longitudinal space of the actuator body. This dimensional transition maintains compactness while achieving proper weight balance and minimizing vibration.
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 configuration reduces the need for larger attachment flanges, decreases the size and weight of the EHA system, and enhances vibration stability by maintaining the center of gravity on or near the center axis, thus meeting aircraft vibration requirements effectively.
Implementation Method 1
a hydraulic pump driven to supply operation oil to the actuator body
Implementation Method 2
an electric motor configured to drive the hydraulic pump
Implementation Method 3
an actuator body which includes a piston and a cylinder and which is extendable in a direction along a center axis
Data Source
AI summary
An electro hydrostatic actuator includes an actuator body, a hydraulic pump driven to supply operation oil to the actuator body, and an electric motor configured to drive the hydraulic pump. Each of the hydraulic pump and the electric motor is placed so as to surround the outer periphery of the actuator body, and the hydraulic pump and the electric motor are arranged in a direction along a center axis.