Sealed Combustion Linear Actuator Exhaust Venting
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Solution Overview
Problem
Hopping robots equipped with combustion-powered linear actuators face issues such as magnet fouling and contamination due to unsealed combustion gas exhaust ports, leading to operational hindrances and premature wear in harsh environments.
Innovation Solution
A sealed combustion-powered linear actuator design with a magnetic latch protected from the environment, featuring a vent region for exhaust gases to exit when the piston extends, and a coaxial low resistance exhaust path to prevent contamination and fouling, ensuring the actuator remains sealed when retracted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the magnet is exposed to the environment for latching the piston, then the latching function is achieved, but the magnet becomes fouled when the piston extends
Solution Approach 1:
A non-ferrous isolator is introduced as an intermediary component between the magnet and the combustion chamber. This isolator allows the magnetic field to pass through for latching functionality while preventing combustion byproducts and contaminants from directly contacting the magnet, thus eliminating fouling issues
Solution Approach 2:
The magnet is extracted from direct environmental exposure by placing it within a sealed flux guide assembly that is isolated from the combustion chamber. The magnetic field extends through the isolator to perform latching without the magnet being exposed to harmful environmental factors
2Productivity
If the exhaust ports are open for combustion gas venting, then exhaust gases can exit the actuator, but the components become contaminated in harsh environments
Solution Approach 1:
The seal configuration is made dynamic by positioning it to respond to piston movement. When the piston is retracted, the seal engages with the vent region to close the exhaust ports and prevent contamination. When the piston extends, the seal retracts allowing exhaust gases to vent freely
Solution Approach 2:
The exhaust ports undergo periodic opening and closing cycles synchronized with piston movement. The ports are closed during the retracted position to prevent contamination and opened during extension to allow exhaust venting, creating a rhythmic protective action
3Reliability
If the piston is sealed with respect to the actuator body, then contamination is prevented, but exhaust gases cannot exit the actuator when the piston extends
Solution Approach 1:
The seal is designed to be dynamic rather than static, allowing it to change its sealing engagement based on piston position. The seal maintains contact with the vent region when retracted for sealing, but retracts to allow exhaust passage when the piston extends
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 solution effectively prevents contamination and fouling, ensuring reliable operation and extended lifespan of the actuator by isolating the magnetic latch and providing a wear-resistant design that allows easy retraction and latching, even in harsh conditions.
Implementation Method 1
A first seal is disposed about the piston and seals the piston with respect to the actuator body
Implementation Method 2
A vent region in the body of increased diameter allows exhaust gases to bypass the first seal to a space between the piston and the actuator body and to vent out of the actuator body
Implementation Method 3
A second seal proximate the distal end of the actuator body cooperates with a seal body to seal the vent region when the piston is retracted
Implementation Method 4
the actuator piston is releasably latched to the actuator body via a magnet
Implementation Method 5
A non-ferrous magnet isolator may be disposed at least partially about the magnet
Data Source
AI summary
A combustion powered linear actuator features an actuator body having a first chamber therein and a power piston mounted in the first chamber movable between retracted and extended positions. The power piston has a combustion chamber therein. A first seal about the piston seals the piston with respect to the actuator body. A vent region in the body of increased diameter allows exhaust gases to bypass the first seal and flow into a space between the piston and the actuator body and to then vent out of the actuator body. A second seal proximate the distal end of the actuator body cooperates with another piston seal to seal the annular region when the piston is retracted. The vent region may include a vent gland in the first chamber about the piston defining a vent chamber between the actuator body and the vent gland.