Thrust Bearing Sliding Layer Fiber Orientation Against Cracks
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Solution Overview
Problem
Existing sliding members for thrust bearings are prone to damage from cracks and shear between the sliding layer and the back-metal layer during the stopping period due to uneven elastic deformation and load distribution, particularly when fibrous particles are dispersed in a non-oriented or anisotropic manner.
Innovation Solution
A sliding member with a partial annular shape featuring a sliding layer composed of synthetic resin and fibrous particles, where the fibrous particles are oriented differently in the sliding surface side region and the interface side region to enhance deformation resistance, with specific particle size and volume ratios, and the inclusion of a porous metal portion on the back-metal layer to improve bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fibrous particles are dispersed in a non-oriented or isotropic manner in the sliding layer, then the sliding layer has uniform properties in all directions, but the resin composition near the sliding surface is largely deformed during stopping period, leading to cracks
Solution Approach 1:
The patent applies local quality by creating different fibrous particle orientation patterns in different regions of the sliding layer. Specifically, the surface side region has fibrous particles oriented substantially parallel to the sliding surface to resist deformation during stopping period, while the intermediate region has particles oriented substantially perpendicular to prevent crack propagation. This regional differentiation resolves the contradiction between uniformity and deformation resistance.
2Strength
If fibrous particles are dispersed such that more particles have major axes oriented perpendicular to the sliding surface, then the sliding layer has improved resistance to crack propagation, but the load is not effectively transmitted to the back-metal layer interface, reducing overall strength
Solution Approach 1:
The patent uses local quality by orienting fibrous particles perpendicular to the sliding surface specifically in the intermediate region (at a thickness of 15 to 50% from the interface), while maintaining parallel orientation in the surface side region. This localized perpendicular orientation provides crack resistance where needed without compromising overall load transmission capability.
Solution Approach 2:
The patent segments the sliding layer into two distinct regions: a surface side region and an intermediate region, each with different fibrous particle orientations. The surface side region (closer to sliding surface) has particles oriented parallel to the sliding surface for load bearing, while the intermediate region has particles oriented perpendicular for crack resistance. This segmentation allows simultaneous optimization of both load transmission and crack propagation resistance.
3Strength
If fibrous particles are oriented substantially parallel to the sliding surface throughout the entire sliding layer, then the sliding layer has high strength parallel to the surface, but shear force at the interface between sliding layer and back-metal layer causes peeling off
Solution Approach 1:
The patent applies local quality by creating different fibrous particle orientations in different regions. The surface side region has particles oriented parallel to the sliding surface to provide high strength for load bearing, while the intermediate region has particles oriented perpendicular to the sliding surface to resist shear forces and prevent peeling at the interface, thereby maintaining bonding stability.
4Ease of manufacture
If the interface side region thickness is less than 15% or more than 50% of the sliding layer thickness, then manufacturing is simplified, but the sliding layer cannot effectively resist both deformation and shear forces simultaneously
Solution Approach 1:
The patent uses parameter changes by specifying a precise thickness range for the interface side region (15 to 50% of total sliding layer thickness). This parameter optimization ensures that the intermediate region with perpendicular fibrous particles is sufficiently thick to resist shear forces and prevent peeling, while not being so thick as to compromise the overall structural integrity and deformation resistance of the sliding layer.
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 significantly reduces the likelihood of internal cracks and shear between the sliding layer and the back-metal layer by dispersing the load effectively across the sliding surface, enhancing the sliding member's resistance to deformation and wear resistance.
Implementation Method 1
a resin composition including fibrous particles, such as glass fibrous particles, carbon fibrous particles or intermetallic compound fibrous particles, dispersed in the synthetic resin to increase strength of the sliding layer
Implementation Method 2
the resin composition near the sliding surface is drawn by the shaft member and elastically deformed in a rotation direction of the shaft member
Implementation Method 3
a fluid lubricating film, such as oil film, is formed between a surface of a shaft member and a sliding surface of a sliding member, thereby a direct contact between the shaft member and the sliding member is prevented
Data Source
AI summary
A sliding member for a thrust bearing is provided. A sliding layer includes fibrous particles dispersed in a synthetic resin, and has a sliding surface side region and an interface side region. The particles have an average particle size Dsur, first and Dsur, second respectively in first and second cross-sections in the sliding surface side region, and Dint, first and Dint, second respectively in first and second cross-sections in the interface side region. Dsur, first and Dint, second are 5-30 μm, and Dsur, second and Dint, first are 5 to 20% of respectively Dsur, first and Dint, second. A dispersion index of the particles having the major axis length of 20 μm or longer is 5 or more, both in the sliding surface side region in view of the first cross-section and in the interface side region in view of the second cross-section.