Dynamic-Pressure Seal Ring Structure for Lower Sliding Resistance
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Solution Overview
Problem
Conventional seal rings used in automatic transmissions and continuously variable transmissions face challenges in reducing sliding resistance to enhance fuel efficiency, as they generate friction that reduces output torque and durability.
Innovation Solution
A seal ring design featuring recessed parts with dynamic pressure and introduction parts, along with inclined inner peripheral wall surfaces, which utilize the dynamic pressure effect to reduce sliding resistance and improve durability by minimizing contact area and abrasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal ring contacts the shaft groove side surface to seal the gap, then sealing performance is improved, but sliding resistance increases reducing output torque
Solution Approach 1:
The side surface of the seal ring is segmented into multiple recessed parts (first, second, third recessed parts) that divide the contact area with the shaft groove. This segmentation reduces the continuous sliding contact area while maintaining sealing effectiveness at the groove interface, thereby reducing sliding resistance and energy loss.
Solution Approach 2:
The seal ring features localized recessed parts with specific depths and positions on the side surface, creating areas of reduced contact pressure and sliding resistance. The first recessed part at the groove side provides primary sealing with reduced friction, while additional recessed parts optimize the local contact characteristics to minimize energy loss.
2Loss of energy
If the contact area between seal ring and shaft is reduced to lower sliding resistance, then fuel efficiency is improved, but sealing reliability may deteriorate
Solution Approach 1:
The side surface is divided into multiple recessed parts that collectively reduce the total contact area while maintaining distributed sealing points. The first recessed part (deepest) provides primary sealing, the second recessed part provides secondary sealing, and the third recessed part enhances sealing at the groove interface, ensuring reliability is maintained despite reduced overall contact area.
Solution Approach 2:
Different recessed parts are positioned at specific locations along the side surface to optimize local sealing functions. The varying depths and positions of the recessed parts create localized sealing zones that maintain reliable sealing while minimizing the total sliding contact area, thus improving fuel efficiency without compromising sealing reliability.
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 design effectively reduces sliding resistance and enhances durability by leveraging the dynamic pressure effect and minimizing contact area, allowing for improved fuel efficiency and performance under high PV conditions.
Implementation Method 1
a very small amount of operation oil is supplied from the recessed part to between the sliding surfaces to utilize a dynamic pressure effect from the operation oil
Data Source
AI summary
A recessed part formed on a side surface includes a dynamic pressure part extending in the circumferential direction to converge on the side surface, and an introduction part extending from the dynamic pressure to open the dynamic pressure part toward the inner periphery side. One or two inner peripheral wall parts are provided for each of the recessed parts. The inner peripheral wall part is a portion defined on the inner periphery side of the corresponding recessed part by the dynamic pressure part and the introduction part. The inner peripheral wall part includes an inner peripheral wall surface. The inner peripheral wall surface extends toward the introduction part in the circumferential direction with inclining with respect to the side surface such that the inner peripheral wall surface is depressed from the side surface.