Stepped Bearing Seal with Three Lips for Low-Friction Contamination Control
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Solution Overview
Problem
Existing bearing units for rotary shafts do not provide an effective seal, especially in contaminated environments, and struggle to achieve a balance between sealing performance and low frictional resistance, leading to increased power losses.
Innovation Solution
A bearing unit with a sealing device featuring more than two contacting lips, specifically three radial contacting lips, where the radially inner ring has a step creating different radial interferences for each lip, optimizing sealing performance while minimizing frictional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If more than two contacting lips are used in the sealing device, then sealing performance is improved, but frictional resistance and power losses increase
Solution Approach 1:
The patent applies local quality by creating different radial interference conditions for different lips through the stepped configuration of the inner ring. The first lip contacts the inner ring at a first radial interference, while the second and third lips contact at a second radial interference that is smaller than the first. This local differentiation allows each lip to contribute to sealing performance while controlling the overall frictional resistance by reducing contact pressure on inner lips.
2Reliability
If a customized sealing component is designed for specific application, then sealing performance is improved, but device complexity and cost increase
Solution Approach 1:
The patent achieves universality by designing a sealing device with a standardized elastomer lining and stepped inner ring configuration that can be applied across different bearing applications. The stepped configuration provides a general solution for achieving good sealing performance without requiring customized components for each specific application, thereby reducing device complexity and cost while maintaining effective sealing.
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 achieves excellent sealing performance with minimal impact on frictional resistance and power losses, allowing for standardization and cost-effectiveness without the need for customized components.
Implementation Method 1
The elastomer lining is provided with a pair of contacting lips that make sliding contact with the inner ring to create a seal against external contaminants
Data Source
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AI summary
Bearing unit (1) having a central axis (X) and provided with: - a stationary radially outer ring (31), - a rotary radially inner ring (34), - a sealing device (40), arranged between the radially outer ring (31) and the radially inner ring (34), and in turn comprising: - a shaped shield (41) mounted stably on the radially outer ring (31), and - an elastomer lining (42) on the shaped shield (41), which has more than two radial contacting lips (43, 44, 45), in which - when in use, the contacting lips (43, 44, 45) ensure a sliding contact on a radially outer first surface (34e) and a radially outer second surface (34i) of the radially inner ring (34), - the radially inner ring (34) has a step (34s) so that: - the first surface (34i) is radially more external than the second surface (34e) by the radial length (a) of the step (34s), and - the radial interference (i1) between an axially outer tip (43) and the radially inner ring (34) is smaller than the radial interference (i0) between the axially inner lips (44, 45) and the radially inner ring (34).