Plastic Slinger Labyrinth Seal for Mud and Water Exclusion
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Solution Overview
Problem
Existing sealing arrangements between a shaft and a housing fail to effectively prevent water and debris from entering the lubricated area, especially under dynamic conditions such as high rotational speeds, due to gaps that allow liquids or mud slurry to penetrate, leading to contamination and potential damage.
Innovation Solution
A plastic slinger with a radially extending wall portion featuring a raised bumper and an axially protruding labyrinth feature is secured to the shaft, providing a snap-fit design that excludes contaminants by using centrifugal force to prevent liquids/mud slurry from entering the internal cavity, and includes a rubber over-mold for impact resistance and a low friction interface with the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal member is used to seal the gap between housing and shaft, then sealing performance is improved, but gaps still allow liquids or mud slurry to penetrate under dynamic conditions
Solution Approach 1:
The slinger is divided into two semi-circular parts that can be assembled separately and snap-fit together, allowing for better fitment against the housing and shaft while maintaining sealing effectiveness under dynamic conditions
Solution Approach 2:
The invention adds an axial dimension to the sealing approach by using an axially protruding labyrinth feature that extends toward the seal member, creating a multi-dimensional barrier against contaminant penetration rather than relying solely on radial sealing
2Strength
If a raised bumper feature is added to the radially outer surface, then impact resistance is improved, but device complexity increases
Solution Approach 1:
The raised bumper feature is integrated directly into the radially extending wall portion of the slinger as a molded feature rather than being a separate component, providing impact resistance while minimizing additional structural complexity
Solution Approach 2:
The slinger combines plastic material with molded-in rubber over-mold on the raised bumper feature, creating a composite structure that provides both impact resistance and structural integrity without requiring separate components
3Ease of operation
If a two-piece snap-fit design is used, then ease of assembly is improved, but manufacturing precision requirements increase
Solution Approach 1:
The snap-fit connection uses a tapered interface between the two semi-circular parts, allowing the connection to self-align and accommodate minor dimensional variations, thereby reducing the stringency of manufacturing precision requirements while maintaining ease of assembly
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 liquids and contaminants from entering the internal cavity, ensuring reliable sealing and reducing installation stack issues by achieving a zero or minimal gap condition, while maintaining performance across varying rotational speeds.
Implementation Method 1
excludes contaminants by using centrifugal force to prevent liquids/mud slurry from entering the internal cavity
Implementation Method 2
includes a rubber over-mold for impact resistance and a low friction interface with the housing
Data Source
Figure 1
Figure 2
AI summary
A seal assembly (10) includes a housing (12) defining a bore (14) and a shaft (16) received in the bore. A seal member (18) is secured to the housing for sealing a gap between the housing and the shaft. A slinger (40) is secured to the shaft. The slinger being made from plastic and including a first semi-circular part and a second semi-circular part that is secured to the first semi-circular part. The slinger includes a radially extending wall portion (44) with a raised bumper feature (48) at a radially outer surface opposing the seal member. The slinger further includes an axially protruding labyrinth feature (46) extending from the radially extending wall portion and toward the seal member. The first semi-circular part and the second semi-circular part can be snap fit to one another.