Dynamic Lip Seal with Centrifugal Deflection for Railway Bearings
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Solution Overview
Problem
Conventional radial lip seals generate excessive friction and heat at high rotational speeds, making them unsuitable for applications like railway bearings, while non-contact labyrinth seals lack effectiveness under static conditions unless strict tolerance requirements are met.
Innovation Solution
A sealing arrangement comprising a first and second labyrinth seal, along with a radially positioned lip seal, where the lip seal's sealing lip deflects under centrifugal force, reducing contact force and friction, and the labyrinth seals ensure effective sealing under both static and high-speed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional radial lip seal is used to ensure effective sealing under static conditions, then sealing effectiveness is improved, but friction and heat generation increase excessively at high rotational speeds
Solution Approach 1:
The sealing lip is designed with a specific angle (10°-80°) relative to the radial direction, allowing it to dynamically deflect away from the counterface under centrifugal force during rotation. This dynamic adjustment reduces contact force and friction at high speeds while maintaining sealing contact at low speeds or when stationary
Solution Approach 2:
The contact force between the sealing lip and counterface is changed as a function of rotational speed. At low speeds, the lip maintains contact for effective sealing. At high speeds, centrifugal force causes the lip to deflect and reduce contact force, thereby minimizing friction and heat generation
2Object-generated harmful factors
If a non-contact labyrinth seal is used to reduce friction at high speeds, then friction is minimized, but sealing effectiveness deteriorates under static conditions unless strict tolerance requirements are met
Solution Approach 1:
The invention merges the advantages of both lip seals and labyrinth seals by combining a lip seal element with a labyrinth seal structure. The lip seal provides effective sealing under static conditions, while the labyrinth seal reduces friction and prevents contamination at high speeds when the lip deflects away from the counterface
3Reliability
If the sealing lip is designed to maintain constant contact with the counterface to ensure sealing, then sealing effectiveness is improved, but friction increases excessively at high rotational speeds
Solution Approach 1:
The sealing lip is designed with a specific angle (10°-80°) relative to the radial direction, allowing it to dynamically deflect away from the counterface under centrifugal force during rotation. This dynamic adjustment reduces contact force and friction at high speeds while maintaining sealing contact at low speeds or when stationary
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 provides effective sealing under static conditions and minimizes friction at high speeds, preventing contamination and grease leakage, enabling the use of specific greases and maintaining sealing integrity at speeds exceeding 200 km/hr.
Implementation Method 1
The sealing lip has a longitudinal extension in a radial cross section, which extends towards the rotation axis at an angle of between 10° and 80°, when the dynamic seal part is stationary. The sealing lip is thus adapted to deflect away from the counterface under the action of centrifugal force, thereby reducing a contact force of the lip as speed increases
Data Source
Figure 1
AI summary
The invention concerns a sealing arrangement (1), for sealing of a radial gap between relatively rotatable inner and out components, whereby the inner component (3) is rotational about an axis of rotation (a) and the outer component (4) is coaxially arranged around the inner component (3). The sealing arrangement comprises: a dynamic seal part (12) that is mountable to the inner component (3); a static seal part (10) that is mountable to the outer component (4); and first and second labyrinth seals (5, 6), each of which is formed by a gap between at least one set of opposing surfaces on the static and dynamic seal parts. According to the invention, the sealing arrangement (1) further comprises a lip seal (7), which is arranged radially between the first (5) and the second (6) labyrinth seal. The lip seal comprises a sealing lip (8) which is connected to the dynamic seal part (12) and which bears against a radially oriented counterface on the static seal part. Furthermore, the sealing lip (8) has a longitudinal extension (L) in a radial cross section that extends towards the rotation axis (a) at an angle (α) of between 10° and 80°.