Resin Thrust Washer Oil Groove Layout 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 minimize this load more effectively.
Innovation Solution
A thrust washer made of resin with a ring-shaped portion and oil grooves that allow lubricating oil to flow, featuring an oil stop wall to prevent oil from flowing outward, a dynamic-pressure guiding wall surface, and specific groove configurations to optimize the sliding area ratio and oil flow, reducing friction and wear.
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 oil groove is divided into multiple segments: a first oil groove extending from the inner peripheral edge toward the outer peripheral edge, a second oil groove extending from the insertion hole toward the outer peripheral edge, and a communicating oil groove connecting these two grooves. This segmentation allows oil to be distributed to different areas of the sliding surface, creating multiple lubrication zones that effectively reduce sliding load in mixed lubrication conditions.
Solution Approach 2:
Different portions of the sliding surface are provided with different lubrication characteristics through the segmented oil groove configuration. The first oil groove serves areas requiring radial lubrication, the second oil groove serves areas requiring axial lubrication from the insertion hole, and the communicating oil groove ensures both areas are interconnected. This local differentiation of lubrication quality optimizes friction reduction across the entire sliding surface.
2Reliability
If the sliding area ratio is not optimized, then the manufacturing is simpler, but the friction and wear increase
Solution Approach 1:
The patent specifies that the sliding area ratio of the sliding surface should be controlled within a specific range (60% to 85% of the total ring-shaped portion area). By optimizing this parameter, the thrust washer achieves effective friction and wear reduction. The segmented oil groove configuration further refines this by creating localized lubrication zones that enhance the effectiveness of the optimized sliding area ratio.
3Quantity of substance
If oil grooves extend fully to the outer periphery, then oil distribution is maximized, but oil flow control and pressure management become difficult
Solution Approach 1:
The oil groove configuration creates dynamic oil flow paths that adapt to the thrust washer's operating conditions. The communicating oil groove connects the first and second oil grooves, allowing oil to flow dynamically between radial and axial paths based on pressure differentials and rotational speed, optimizing both distribution and pressure management.
Solution Approach 2:
The communicating oil groove acts as an intermediary channel that mediates between the first oil groove (radial lubrication path) and the second oil groove (axial lubrication path from insertion hole). This intermediary structure allows controlled oil transfer between the two paths, balancing oil distribution with pressure management.
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 sliding load and friction, achieving a sliding area ratio within a range that minimizes torque and abrasion, thereby enhancing the performance and longevity of the thrust washer.
Implementation Method 1
a lubricating state of the thrust washer is supposed to reside in a mixed lubrication region in a Stribeck chart. Thus, it is considered that a part of the thrust washer is separated from the mating member by an oil film of the lubricating oil
Implementation Method 2
a 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
Data Source
AI summary
A thrust washer is provided with a ring-shaped portion that surrounds an insertion hole, the thrust washer is provided with a sliding surface and an oil groove configured to allow lubricating oil to flow in, the oil groove is provided with an opening portion configured to allow the lubricating oil to flow in from the insertion hole side in an inner peripheral end side, an outer periphery end side of the ring-shaped portion of at least one of the oil groove is provided with an oil stop wall which is configured to suppress flow of the lubricating oil toward an outer periphery side of the ring-shaped portion, and a sliding area ratio of each of the sliding surfaces to a projection plane in plan view of the ring-shaped portion is provided within a range of from 60% to 85%