Thrust Bearing Sliding Layer with Anisotropic Thermal Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thrust bearing sliding members with synthetic resin compositions are prone to surface cracks and shear failure due to thermal expansion and pressure from fluid films, especially at high speeds, leading to reduced durability and performance.
Innovation Solution
A sliding member with a partially annular shape, featuring a back-metal layer and a synthetic resin sliding layer with controlled linear expansion coefficients in different directions, incorporating specific materials like polyether ether ketone and fibrous particles, and a porous metal portion for enhanced bonding, to manage thermal expansion and reduce the likelihood of cracks and shear failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the shaft rotates at high speed, then the bearing capacity increases, but centrifugal force causes the resin composition to be pressed and elastically deformed, leading to surface cracks
Solution Approach 1:
The patent changes the physical parameters of the resin composition by controlling its thermal expansion characteristics. Specifically, it adjusts the linear expansion coefficient in the thickness direction (KT) to be 1.05 or more times the linear expansion coefficient in the radial direction (KJ), creating anisotropic thermal expansion that compensates for the elastic deformation caused by high-speed rotation and fluid film pressure, thereby preventing surface cracks
Solution Approach 2:
The patent uses composite materials by dispersing inorganic particles (such as glass fibers, carbon fibers, or ceramic particles) within the synthetic resin matrix. This composite structure enhances the mechanical strength and dimensional stability of the sliding layer, enabling it to resist the elastic deformation and centrifugal forces during high-speed operation without developing surface cracks
2Device complexity
If the resin composition is thermally expanded isotropically, then the material structure is simple, but shear failure occurs at the interface between the back-metal layer and sliding layer
Solution Approach 1:
The patent changes the thermal expansion parameters from isotropic to anisotropic by specifically controlling the ratio between the linear expansion coefficient in the thickness direction (KT) and the linear expansion coefficient in the radial direction (KJ). This parameter modification creates differential thermal expansion that reduces shear stress at the back-metal layer interface, preventing shear failure while maintaining material structure simplicity
Solution Approach 2:
The patent utilizes thermal expansion effects by designing the resin composition to have controlled anisotropic expansion characteristics. The sliding layer is engineered to expand more in the thickness direction than in the radial direction during thermal cycling, which compensates for the shear deformation at the metal-resin interface caused by thermal gradients during operation
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 controlled thermal expansion characteristics and material composition of the sliding member significantly reduce the occurrence of cracks and shear failure, enhancing the durability and reliability of the thrust bearing under high-speed and high-pressure conditions.
Implementation Method 1
when the shaft rotates with a high speed, a centrifugal force has a large influence on the fluid film
Implementation Method 2
if the resin composition of the sliding layer is thermally expanded, due to frictional heat generated by sliding, in an almost isotropic manner in an in-plane direction of the sliding surface
Implementation Method 3
due to frictional heat generated by sliding
Data Source
AI summary
Provided is a sliding member for a thrust bearing. The sliding member includes a back-metal layer and a sliding layer, and has a partially annular shape. The sliding layer includes a synthetic resin and has a sliding surface. In a center line region of the sliding layer, the sliding layer has a linear expansion coefficient KS in a direction parallel to a circumferential direction of the sliding member, a linear expansion coefficient KJ in a direction parallel to a radial direction of the sliding member, and a linear expansion coefficient KT in a direction perpendicular to the sliding surface, and the linear expansion coefficients KS, KJ, and KT satisfy the following relations (1) and (2): Relation (1): 1.1≤KS/KJ≤2; and Relation (2): 1.3≤KT/{(KS+KJ)/2}≤2.5.