Segmented Face Seal Design for Wheel Assembly Heat Management
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Solution Overview
Problem
Conventional face seals for rotating shafts in rubber-tracked vehicles are prone to misassembly, misalignment, wear, and overheating due to their design, which leads to increased heat production and excessive load on bearings, necessitating larger seals that are not optimally sized relative to the bearings.
Innovation Solution
A face seal design comprising a first and second half, each with an inner L-shaped sealing ring, an elastomeric ring, and an integrally bonded outer Z-shaped ring, which allows for a smaller seal diameter by providing positive depth control and support for seal face loads, reducing the need for a larger seal size and minimizing heat production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional face seal designs are used with rubber-tracked vehicles, then the seals can handle high travel speeds and tractive effort, but the seals produce excessive heat and require larger sizes that increase load on bearings
Solution Approach 1:
The face seal is divided into two separate halves (first face seal half and second face seal half) that are assembled together. Each half contains an inner sealing ring, elastomeric ring, and outer ring. This segmentation allows for better heat dissipation compared to a single large seal, reducing the temperature issue while maintaining the required sealing capability for high-speed applications.
Solution Approach 2:
The invention introduces depth control features (seating flange on the outer ring and shoulder on the inner sealing ring) that control the axial position and orientation of the seal halves. This dimensional control allows the seal to be properly positioned and oriented, ensuring optimal sealing performance while using a smaller, more compact design that reduces bearing load.
2Force
If larger face seals are used to handle high tractive effort and track tension, then the seals can withstand the loads, but the seals produce more heat and are not optimally sized relative to the bearings
Solution Approach 1:
By splitting the seal into two halves, each carrying a portion of the sealing and load-bearing function, the design achieves the required force capacity without needing a single oversized seal. The segmented structure allows for more efficient heat dissipation across a larger surface area relative to the volume, reducing operating temperature while maintaining the ability to handle high tractive effort and track tension.
Solution Approach 2:
The face seal combines multiple materials with different properties: metal inner sealing rings for structural strength and heat resistance, elastomeric rings for sealing flexibility, and outer rings with integrated seating flanges for load distribution. This composite construction allows the seal to withstand high forces while managing heat generation more effectively than a single-material design.
3Reliability
If two-piece metal face seals are used, then the seals can provide adequate sealing, but the seals are prone to misassembly, misalignment, wear, and damage
Solution Approach 1:
The outer rings are designed with integrated seating flanges that engage with corresponding features in the housing before the sealing surfaces are assembled. This preliminary positioning action ensures proper alignment and orientation of the seal halves during assembly, preventing misalignment issues. The flanges act as guides that pre-position the components correctly before final sealing engagement.
Solution Approach 2:
The elastomeric rings serve as intermediaries between the inner sealing rings and the outer rings, providing flexibility and tolerance for minor misalignments. The elastomeric material allows the seal to accommodate small variations in assembly while maintaining effective sealing, reducing the severity of misalignment issues that would occur with rigid metal-to-metal connections only.
4Temperature
If face seals are made smaller to reduce heat production, then the heat and bearing load are reduced, but the seals may not have sufficient capacity for high tractive effort and track tension
Solution Approach 1:
The segmented two-half design increases the effective surface area for heat dissipation without proportionally increasing the load-bearing capacity in a single direction. Each half contributes to the overall sealing and load distribution, allowing the seal to be more compact (generating less heat) while still handling high forces through the combined capability of both halves working together in the face-to-face configuration.
Solution Approach 2:
The combination of metal components for structural strength and elastomeric materials for flexible sealing allows the seal to maintain high load-carrying capacity in a more compact design. The metal outer rings with seating flanges handle the mechanical loads and positioning, while the elastomeric rings provide sealing compliance, enabling a smaller overall seal size that generates less heat while still withstanding high tractive effort and track tension.
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 design enhances the reliability of rubber-track vehicle wheel assemblies by reducing heat production and reactive forces on bearings, while maintaining effective sealing and flexibility across varying temperatures, thus improving the operational efficiency and longevity of the seals.
Implementation Method 1
an elastomeric ring disposed over the inner sealing ring
Implementation Method 2
an integrally bonded outer ring
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4C
AI summary
A face seal (10) comprises a first half and a second half. Each half of the face seal comprises an inner sealing ring (20), the inner sealing ring (20) being generally L-shaped in cross-section, an elastomer ring (30) disposed over the inner sealing ring (20), and an outer ring (40) disposed over the elastomeric ring (30), the outer ring (40) being generally Z-shaped in cross-section. The inner sealing ring (20) comprises an axially extending circular cylindrical portion (21), a radially extending planar ring portion (22) coupled to the cylindrical portion (21), and a sealing surface defined by the seal side planar wall (26). The outer ring (40) comprises an axially extending second circular cylindrical portion (41), a seating flange (42) extending radially outward from a front end of the second cylindrical portion (41), and a backing flange (43) extending radially inward from the rear end of the second cylindrical portion (41).