Linear Actuator Seal Package for Runout and Contamination Control
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Solution Overview
Problem
Linear actuators face challenges in preventing fluid and particle contamination in outdoor and industrial environments, particularly due to issues with existing sealing mechanisms that fail to effectively manage runout and non-linear motion, leading to ingress of debris and fluids.
Innovation Solution
A linear actuator design incorporating a combination of a first lip seal, a felt ring, and a radially floating second lip seal, where the second seal is axially and radially floating, supported by a spring element, to create a sealing package that accommodates runout and non-linear motion, preventing contamination ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed seal is used to prevent contamination, then sealing effectiveness is improved, but the seal cannot accommodate runout and non-linear motion
Solution Approach 1:
The patent employs dynamic sealing elements including a floating seal that can move radially and axially to accommodate runout and non-linear motion of the inner arm, and a spring element that provides continuous contact force to maintain sealing effectiveness despite motion variations
Solution Approach 2:
The patent changes the physical state and positioning parameters of the sealing system by allowing radial and axial floating of the second seal, and using spring force to maintain optimal contact pressure between sealing elements and the inner arm surface
2Device complexity
If a simple seal structure is used, then device complexity is reduced, but sealing reliability under excessive runout deteriorates
Solution Approach 1:
The patent divides the sealing system into multiple independent sealing elements (first lip seal, felt ring, second floating lip seal) arranged in series, where each element handles specific aspects of the sealing challenge, improving overall reliability without requiring a single complex seal
Solution Approach 2:
The patent introduces a spring element as an intermediary component between the sealing elements and the housing, which actively maintains contact force and compensates for gaps caused by runout, enhancing sealing reliability
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 sealing package effectively prevents fluid and particle contamination, maintaining a continuous 360-degree seal even with excessive runout, ensuring the longevity of the linear actuator by accommodating manufacturing tolerances and erratic motion.
Implementation Method 1
the linear actuator includes a spring element separate from the first seal and the second seal and axially arranged between the first seal and the second seal. The spring element can springably support the second seal such that the entirety of the second seal floats axially relative to the outer housing via the spring element
Implementation Method 2
The first seal, felt ring, and the second seal can be configured to sealingly engage the inner arm
Data Source
AI summary
A linear actuator includes an outer housing, an inner arm disposed within and extending from an open end of the outer housing, and a seal arranged radially between the outer housing and the inner arm so as to prevent passage of fluid and particle contamination between the outer housing and the inner arm. The seal includes a first seal, a second seal, and a felt ring configured to sealingly engage the inner arm.