Multi-stage wheel-hub sealing assembly with deflector screens
Solution Overview
Problem
Existing sealing assemblies for wheel-hub units in vehicles face challenges in reducing frictional torque while maintaining high protection against contaminants, and their increasing complexity is unprofitable due to market demands for reduced fuel consumption and emissions.
Innovation Solution
A multi-stage low-friction sealing assembly is designed with a combination of stainless-steel screens and an elastomeric lip seal, featuring a synergistic arrangement of sealing stages, including an annular cavity, labyrinth seals, and deflector screens to minimize contact friction and effectively prevent contaminant entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the geometrical complexity of screens and/or the number of sealing lips is increased to improve sealing performance, then contaminant protection is enhanced, but frictional torque increases and manufacturing costs rise
Solution Approach 1:
The sealing assembly is divided into multiple independent sealing stages (first sealing stage with first screen and first sealing lip, second sealing stage with second screen and second sealing lip) arranged in series. Each stage provides independent sealing action, allowing the system to achieve high sealing performance through the cumulative effect of multiple simple stages rather than through complex single-stage designs.
Solution Approach 2:
The sealing lips are arranged axially along the rotation axis at different positions, creating a multi-dimensional sealing barrier. The first sealing lip is positioned at a first axial location while the second sealing lip is positioned at a second axial location, forming a staggered sealing configuration that enhances protection without requiring increased complexity in any single plane.
2Reliability
If the geometrical complexity of screens and/or the number of sealing lips is increased to improve sealing performance, then contaminant protection is enhanced, but frictional torque increases
Solution Approach 1:
The sealing function is segmented across multiple independent stages, each with simple geometric screens and single sealing lips. This segmentation allows each stage to provide adequate sealing with minimal friction, while the series arrangement of stages achieves cumulative sealing effectiveness without the friction penalty of complex single-stage designs.
Solution Approach 2:
Each sealing stage is designed with locally optimized simple geometry - the first screen has a first geometric configuration suited for its position, and the second screen has a second geometric configuration suited for its position. This local optimization allows each stage to achieve effective sealing with minimal friction, avoiding the need for overall system complexity.
3Reliability
If the geometrical complexity of screens and/or the number of sealing lips is increased to improve sealing performance, then contaminant protection is enhanced, but manufacturing costs increase
Solution Approach 1:
The sealing assembly is segmented into multiple independent stages that can be manufactured separately and assembled. Each stage uses simple geometric screens and single sealing lips that are easier and less costly to manufacture than complex single-stage designs. The modular segmented structure allows for simplified manufacturing processes and reduced overall costs while maintaining high sealing performance.
Solution Approach 2:
Multiple simple sealing stages are merged into a single integrated sealing assembly that functions as a unified protective barrier. The first sealing stage and second sealing stage are combined in series, providing cumulative sealing effectiveness that exceeds what could be achieved by a single complex stage, while the simplicity of each individual stage keeps manufacturing costs low.
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 assembly significantly reduces frictional torque and enhances contaminant protection with a simplified design, reducing manufacturing costs and improving sealing performance beyond single-stage solutions.
Implementation Method 1
forming labyrinth seals
Implementation Method 2
deflector screens
Implementation Method 3
an elastomeric lip seal
Data Source
AI summary
Low-friction sealing assembly for a vehicle wheel-hub unit inserted inside an annular interspace defined between a flanged rotating element and a stationary element, coaxial with each other, of the wheel-hub unit to protect at least one ring of revolving bodies arranged between the stationary element and the rotating element, and having a first annular screen and a second annular screen during use integral with the rotating element and with the stationary element; and an annular seal having lips that extend axially and radially projecting from the first screen towards the second screen inside an annular chamber defined by the first and second screens; the sealing assembly being a multi-stage sealing assembly provided with a first inner collecting stage designed to collect and expel some of the contaminants.