Large Rolling Bearing Gap Seal for Overpressure and Gap Widening
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Solution Overview
Problem
Existing large slewing bearings, particularly in wind turbine blade bearings, face challenges in maintaining effective sealing against grease leakage and ingress of contaminants due to deformation and overpressure, with existing seals failing to reliably compensate for gap widening and maintain sealing under dynamic conditions.
Innovation Solution
A large rolling bearing with an annular gap seal featuring multiple sealing lips and a fourth sealing lip that interacts with a dedicated sealing surface, ensuring stable positioning under overpressure, and additional sealing planes to maintain sealing effectiveness even under radial movement and overpressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static seal is used to prevent grease leakage in large rolling bearings, then sealing against grease escape is improved, but the seal cannot reliably compensate for gap widening of several millimeters caused by load-induced radial movement
Solution Approach 1:
The seal is designed with a flexible sealing lip that can dynamically adapt to gap variations. The sealing lip is supported by a resilient element (spring or elastomeric material) that allows it to move radially outward to maintain contact with the sealing surface despite gap widening of several millimeters caused by load-induced radial movement between bearing rings.
Solution Approach 2:
The seal structure incorporates a resilient element that changes its physical state under pressure. When overpressure occurs during relubrication, the resilient element deforms to allow the sealing lip to move and maintain sealing contact, rather than rigidly resisting the pressure change.
2Adaptability or versatility
If the seal is designed to bridge changes in sealing gap due to radial movement, then adaptability to gap widening is improved, but reliable installation positioning becomes more difficult
Solution Approach 1:
An installation groove is provided in the bearing ring that preliminarily positions the seal in its correct location before operation. This groove guides the seal into proper alignment during installation, ensuring that the sealing lip is correctly oriented toward the gap between the bearing rings, thereby facilitating reliable positioning despite the seal's flexible design.
3Stress or pressure
If the seal must withstand overpressure of 3 bar or more during operation, then sealing under pressure is improved, but the risk of seal damage and grease leakage increases
Solution Approach 1:
The seal incorporates a resilient element (spring or elastomeric material) that changes its physical state under pressure. When overpressure of 3 bar or more occurs during operation or relubrication, the resilient element deforms to allow the sealing lip to move and maintain sealing contact, distributing the pressure stress and preventing seal damage.
Solution Approach 2:
The resilient element acts as a cushioning mechanism that absorbs and distributes overpressure before it can damage the seal. The spring or elastomeric material is pre-positioned to provide this cushioning effect, allowing the seal to withstand high pressures during relubrication without compromising integrity.
4Reliability
If a projection is added to prevent the sealing lip from being forced out during overpressure, then seal stability is improved, but rotational resistance increases due to additional contact
Solution Approach 1:
The resilient element provides localized support specifically at the sealing lip, allowing it to maintain contact with the sealing surface under overpressure without requiring additional contact surfaces that would increase rotational resistance. The support is applied only where needed to maintain sealing effectiveness.
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 enhanced sealing performance, maintaining sealing integrity under overpressure and dynamic conditions, reducing wear and extending service life by ensuring the sealing lips remain stable and effective even with gap widening, while preventing grease leakage and ingress of contaminants.
Implementation Method 1
The gap seal (4) has a sealing base (5) which is received in an anchoring groove (6) provided in the first bearing ring (1). The gap seal (4) has a first sealing lip (7), a second sealing lip (8) and a third sealing lip (9)... supported by a resilient element... allowing radial movement between the bearing rings
Implementation Method 2
The gap seal (4) has a fourth sealing lip (14) which prevents escape of grease... The fourth sealing lip (14) bears against a fourth sealing surface (15)... formed on a section of the second bearing ring (2) which bounds the gap (3) in the radial direction (R)
Data Source
Figure 1
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AI summary
The present invention relates to a large rolling bearing having a first and a second bearing ring and a gap seal. The gap seal has a total of four sealing lips. The aim of the present invention is to provide a large rolling bearing having improved sealing. To achieve this aim, the gap seal (4) has a fourth sealing lip (14) disposed in the gap (3), the fourth sealing lip extending into the gap (3) and being supported on a fourth sealing face (15), the fourth sealing face (15) being formed on a portion of the second bearing ring (2) which delimits the gap (3) in the radial direction, and the fourth sealing face (15) being located behind the third sealing face (13), as seen from the outside (A) of the large rolling bearing.