Seal Ring Recessed Sections for Automatic Transmission Friction
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Solution Overview
Problem
Current seal rings for automatic transmissions face challenges in reducing drive loss and fuel consumption due to high friction and oil leakage, with existing solutions offering limited friction reduction and inadequate leakage prevention.
Innovation Solution
A seal ring design featuring circumferentially spaced recessed sections with curved squeezing portions convex toward pillar sections, enhancing oil squeezing and lift, and inner walls to prevent oil flow, resulting in reduced friction and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a seal ring with tapered side surfaces is used to reduce pressurizing load, then friction is reduced, but oil leakage increases due to line contact at the abutment joint gap
Solution Approach 1:
The contact side-surface is segmented into multiple recessed sections (first, second, third recessed sections) separated by grooves. This segmentation transforms the continuous line contact into distributed point/area contacts at the groove bottoms, reducing wear concentration while maintaining sealing effectiveness across the segmented surfaces.
Solution Approach 2:
Different regions of the seal ring are given different functional qualities: the recessed sections provide sealing contact surfaces with specific curvature radii, the grooves provide lubricant reservoirs and pressure equalization zones, and the abutment joint is designed with specific gap dimensions to balance friction reduction and leakage prevention locally.
2Loss of energy
If the pressurizing load on the contact side-surface is reduced, then friction loss decreases, but oil leakage from the abutment joint gap increases
Solution Approach 1:
The grooves act as intermediary elements between the recessed sections, serving multiple functions: they store lubricant to reduce friction, equalize pressure distribution to prevent excessive leakage, and provide transition zones that maintain sealing while accommodating the reduced pressurizing load condition.
Solution Approach 2:
The curvature radii of the recessed sections are specifically optimized (first recessed section: 0.5-2.0mm, second recessed section: 1.0-3.0mm, third recessed section: 1.5-4.0mm) to change the contact pressure distribution parameters, achieving optimal balance between friction reduction and leakage prevention under reduced pressurizing load conditions.
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 seal ring effectively reduces friction by 10% or more and halves oil leakage, achieving both low-friction and low-leakage characteristics, thereby minimizing drive loss and improving fuel efficiency.
Implementation Method 1
the oil that fills the recessed sections 6 is squeezed along the inclined surfaces of the converging portions 52 to cause lift 60
Implementation Method 2
hydraulic pressure acts on the recessed sections 6 on the contact side-surface to bring about a pressing load reduction effect (cancelling pressure 61)
Data Source
AI summary
Provided is a seal ring which has low-friction characteristics and low-leakage characteristics, reduces drive loss of the automatic transmission of an automobile, and contributes to improvement in fuel consumption of the automobile. The seal ring is attached to a shaft groove on the outer peripheral surface of a shaft. A plurality of recessed sections circumferentially spaced apart from each other with pillar sections interposed therebetween are formed at least on the inner peripheral side of a side surface of the seal ring in contact with the shaft groove. The circumferential opposite ends of each of the recessed sections are formed as squeezing portions formed of curved surfaces convex toward the pillar sections. The depth “h” of a deepest portion in which the axial width of the recessed section is the largest is set in the range of 2 to 17 where the axial width of the seal ring is 100.