Spherical Tilting Pad Bearing Geometry for Lower Wear
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Solution Overview
Problem
Tilting pad bearings in wind turbines and underwater turbines experience high wear due to high contact stress and are limited to non-steel/steel sliding combinations, necessitating a solution for reduced friction and increased durability.
Innovation Solution
A tilting pad bearing design featuring spherical plain bearings with a specific geometric relationship between contact and component bearing surfaces, sealed to prevent lubricant leakage, and fluid distribution structures to maintain lubrication and reduce wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tilting pad bearing design is used with spherical plain bearings, then the bearing can support high loads and allow tilting movement, but high contact stress occurs between sliding surfaces leading to wear and shorter service life
Solution Approach 1:
The bearing surface is segmented into multiple tilting pads that can independently tilt and adjust. Each pad is supported by a bearing element allowing tilting movement, enabling the load to be distributed across multiple segmented surfaces rather than concentrated on a single sliding surface, thereby reducing contact stress and wear.
Solution Approach 2:
The tilting pads and bearing elements are designed with spherical plain bearing geometry, where the tilting segment comprises a convex spherical surface that interacts with a concave spherical surface on the bearing element. This spherical configuration enables smooth tilting movement while distributing contact stress across curved surfaces.
2Strength
If steel/steel sliding combination is used to increase durability, then wear resistance improves, but high contact stress still occurs leading to wear
Solution Approach 1:
The sliding surface is divided into multiple tilting pads that can independently adjust their tilt angle. This segmentation allows the load to be distributed across multiple contact points rather than concentrated on a single steel/steel interface, reducing contact stress even when using durable steel materials.
Solution Approach 2:
The tilting pads are designed with tilting mobility, allowing them to dynamically adjust their orientation in response to bearing load and pressure differences. This dynamic adjustment optimizes the contact distribution across the steel/steel sliding surfaces, preventing localized high contact stress.
3Reliability
If lubricant is supplied to the bearing gap to create hydrodynamic pressure, then the component can float on the lubricant film, but lubricant leakage occurs reducing efficiency
Solution Approach 1:
The bearing element is designed with an equipotential surface that is equipotential with respect to the tilting segment bearing sliding surface. This equipotential configuration helps equalize pressure distribution and prevents lubricant from being forced out of the bearing gap, reducing leakage while maintaining hydrodynamic support.
Solution Approach 2:
The bearing element acts as an intermediary component between the tilting pad and the housing. It provides a sealed environment with an equipotential surface that mediates the lubricant flow, allowing hydrodynamic pressure to build up while preventing leakage to the external environment.
4Reliability
If maintenance-free sliding layers are used to reduce wear, then service life increases, but they cannot handle high loads effectively
Solution Approach 1:
The tilting pads are designed with tilting mobility, allowing them to dynamically adjust their orientation in response to bearing load and pressure differences. This dynamic adjustment optimizes the contact distribution across the sliding surfaces, preventing localized high contact stress.
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 achieves lower surface loads, reduced wear, and increased service life, enabling maintenance-free operation under high loads and speeds, suitable for challenging applications like wind turbines and underwater turbines.
Implementation Method 1
a lubricant film forms between the tilting pad and the component to be supported, on which the component to be supported 'floats,' creating a fluid-filled bearing gap
Implementation Method 2
The lubricant required to generate the hydrodynamic pressure in the bearing gap is supplied to the component bearing surface in the low-pressure area largely without pressure. During operation, the lubricant is drawn into the bearing gap, which increases the pressure in the lubricant in the bearing gap and causes the component to be supported to float.
Data Source
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AI summary
Disclosed is a tilting-pad bearing arrangement (2) for a hydrodynamic plain bearing (1) for hydrodynamically supporting a component (4), wherein the tilting-pad bearing arrangement (2) comprises a tilting pad (20) and a bearing element (30) supporting the tilting pad (20), wherein the tilting pad (20) and the bearing element (30) are designed as spherical plain bearings, in particular as axial spherical plain bearings, and wherein the tilting pad (20) has at least a first and a second surface, wherein the first surface is designed as a hydrodynamic component bearing surface (21) and is configured to hydrodynamically support the component (4) to be hydrodynamically supported, and the second surface is designed as a tilting-pad bearing sliding surface (22) with at least partially an outwardly curved spherical surface, which interacts with a bearing element sliding surface (32) formed on the bearing element (30), which at least partially has an inwardly curved spherical surface,wherein a seal (12) is provided between the tilting pad bearing sliding surface (22) and the bearing element sliding surface (32), which seal closes off a bearing interior (14) defined between the bearing element sliding surface (32) and the tilting pad bearing sliding surface (22) to the outside and delimits a contact surface (23) on the tilting pad (20) in the region of the bearing interior (14), which contact surface is in sliding contact with the bearing element (30), wherein the tilting pad (20) is further dimensioned such that a component bearing projection surface P1 generated by an orthogonal projection of the hydrodynamic component bearing surface (21) is larger than a contact surface projection surface P2 generated by an orthogonal projection of the contact surface (23), wherein a ratio of contact surface projection surface P2 to component bearing projection surface P1 satisfies the following relationship: 0.5 :S P2/P1 < 1.