Oil-Grooved Thrust Washer for Lower Sliding Load
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Solution Overview
Problem
Thrust washers in existing technologies do not effectively reduce sliding load in mixed lubrication regions, leading to increased friction and wear, and there is a demand for a solution that can achieve a greater reduction in sliding load than current designs.
Innovation Solution
A thrust washer design featuring oil grooves with specific inclination angles, dynamic-pressure guiding walls, and a combination of non-communicating and communicating oil grooves to optimize lubrication and reduce sliding load, utilizing a resin material with fiber reinforcement and surface treatments for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional oil groove configurations are used in thrust washers, then the structure is simple and easy to manufacture, but the sliding load is not effectively reduced in mixed lubrication regions
Solution Approach 1:
The patent applies local quality by creating different groove configurations in different regions of the thrust washer. The first oil grooves extend from the inner peripheral edge toward the outer peripheral edge, while the second oil grooves extend from the outer peripheral edge toward the inner peripheral edge. The communicating oil grooves connect these two sets of grooves, creating a localized oil supply system that adapts to the mixed lubrication conditions at different radial positions, thereby reducing sliding load without requiring complete redesign of the entire groove system.
Solution Approach 2:
The patent segments the oil groove system into three distinct components: first oil grooves for radial oil distribution, second oil grooves for circumferential oil distribution, and communicating oil grooves for connecting these systems. This segmentation allows each groove type to perform its specific function optimally, improving overall lubrication effectiveness while maintaining manufacturing simplicity through modular design.
2Reliability
If larger oil grooves are provided to improve lubrication, then lubrication effectiveness increases, but the sliding surface area decreases leading to increased contact stress
Solution Approach 1:
The patent transitions from a single-dimension radial groove design to a two-dimensional oil distribution network by adding circumferential-oriented second oil grooves and communicating grooves. This dimensional expansion allows oil to reach the sliding surface from multiple directions (radially and circumferentially), improving lubrication coverage and effectiveness without requiring excessive groove depth or width that would reduce the load-bearing sliding surface area.
Solution Approach 2:
The patent optimizes the parameters of the oil grooves by specifying that they extend only partially across the thrust washer face rather than covering the entire surface. The first and second oil grooves are positioned to create an optimal balance between oil supply area and load-bearing sliding surface area, ensuring sufficient lubrication while maintaining adequate contact stress distribution across the remaining sliding surface.
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 a significant reduction in sliding load and abrasion, meeting criteria for low torque and small abrasion amounts, while maintaining effective lubrication and wear resistance.
Implementation Method 1
a dynamic-pressure guiding wall surface is provided being adjacent to the oil groove, the dynamic-pressure guiding wall surface guiding the lubricating oil flowed into the oil groove toward the sliding surface and generating dynamic pressure between the sliding surface and another member
Implementation Method 2
lubricating oil is interposed between the thrust washer and the mating member... a specific configuration of the thrust washer, which enables achievement of a reduction in sliding load in the mixed lubrication region
Data Source
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AI summary
Provided is a thrust washer, which enables achievement of a reduction in sliding load. A thrust washer (20) includes: oil grooves (25) formed in at least one of the front surface or the back surface, which are recessed with respect to a sliding surface (26) and are configured to receive lubricating oil flowing thereinto; opening portions (27) formed on an inner peripheral end side of an ring-shaped portion (21) for the oil grooves (25), which are recessed with respect to sliding surface (26) and are configured to allow the lubricating oil to be flowed into the oil grooves (25) from an insertion hole (22) side; and an oil stop wall (28) formed at an end portion of at least one of the oil grooves (25) on an outer periphery side of the ring-shaped portion (21), which is configured to separate the oil groove (25) and an outside of the ring-shaped portion (21) from each other and suppress flow of the lubricating oil flowed into the oil groove (25) to an outer periphery side of the ring-shaped portion (21), the oil stop wall (28) being formed at the same position as a position of the sliding surface (26) in a thickness direction of the oil stop wall (28). A sliding area ratio of each of the sliding surfaces (26) to a projection plane in plan view of the ring-shaped portion is set to fall within a range of from 60% to 85%.