Sliding Member With Raised Overlay For Oil Retention
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Solution Overview
Problem
The existing sliding bearing designs with tapered inner diameters and lubricating oil reservoirs face issues with lubrication oil flow when the engine is stopped, leading to high starting torque due to low oil retention, which results in increased friction and potential seizure.
Innovation Solution
A sliding member with a raised portion along the axial direction, featuring a thickness difference of less than 6 micrometers between the overlay layer at the center and edge, incorporating a binder resin, solid lubricants, and hard particles, which forms a continuous oil-retaining groove to enhance oil retention and reduce friction torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inner diameter is tapered from the center to the edge in the axial direction, then the bearing structure is simplified and manufacturing is easier, but lubrication oil flows from the edge when the engine is stopped, resulting in low oil retention and high starting torque
Solution Approach 1:
The bearing inner surface is segmented into multiple functional zones: a tapered portion for easy manufacturing, a raised portion with increased thickness for oil retention, and a groove portion for oil distribution. This segmentation allows each zone to perform its specific function while collectively solving the contradiction between manufacturing ease and oil retention.
Solution Approach 2:
Instead of uniformly tapering the entire bearing, the invention applies local quality by creating a raised portion with increased thickness at specific locations. This localized thickening provides enhanced oil retention capacity exactly where needed, while the rest of the bearing maintains the simpler tapered structure for ease of manufacture.
2Reliability
If the overlay layer thickness is increased to improve oil retention, then friction torque is reduced, but manufacturing precision requirements increase due to the need to control thickness differences
Solution Approach 1:
The invention applies partial action by increasing the overlay layer thickness only in the raised portion where oil retention is needed, rather than uniformly increasing thickness throughout the entire bearing. The thickness difference is controlled to be within 6 micrometers, providing sufficient oil retention while maintaining reasonable manufacturing precision requirements.
3Quantity of substance
If grooves are provided on the overlay layer to retain oil, then oil retention improves, but the device complexity increases due to additional structural features
Solution Approach 1:
The invention merges multiple functions into the raised portion structure: it serves as both an oil reservoir (retaining lubrication oil) and an oil distribution system (through the integrated groove). This merging reduces device complexity compared to having separate reservoirs and distribution channels, while still achieving effective oil retention.
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 effectively retains lubrication oil, reducing the starting torque and preventing seizure by maintaining a thicker oil film, thereby improving engine starting efficiency and fuel economy.
Implementation Method 1
the raised portion includes a top between a starting point and the edge of the sliding member in the axial direction... provision of a sliding member with an improved function to retain oil
Implementation Method 2
The overlay layer may consist of at least one of a solid lubricant and hard particles in addition to a binder resin... reducing the starting torque and preventing seizure by maintaining a thicker oil film
Data Source
Figure 1~2
Figure 3(a)~3(b)
Figure 4~5(b)
AI summary
A sliding member includes: a lining layer formed from an alloy having a predetermined shape; and an overlay layer formed on an inner circumferential surface of the lining layer, the overlay layer being formed of a resin, the overlay layer sliding with a shaft, the overlay layer including a raised portion a height of which in a predetermined area including each of an edge in an axial direction of the shaft is greater than a height of another area of the overlay layer.