Piston Seal Assembly with Retractable Guard for Extrusion Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piston seal assemblies in automotive transmissions are prone to failure due to extrusion of the seal into the gap between the piston and the plate, leading to leakage and malfunction.
Innovation Solution
A piston seal assembly design featuring a recess on the piston with a radial sealing surface and an axially movable seal, supported by a jacket to prevent extrusion, utilizing a 35% glass fiber filled polytetrafluoroethylene (PTFE) seal material with an interference fit, and a steel jacket to constrain deformation and ensure reliable sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the seal is allowed to axially shift during opposite direction movement to allow hydraulic fluid flow, then fluid flow is enabled, but the seal can extrude into the gap between piston and plate causing failure
Solution Approach 1:
A retractable guard member is introduced as an intermediary component between the seal and the gap. The guard member prevents the seal from extruding into the gap while still allowing hydraulic fluid to flow past the seal assembly during reverse movement, thus resolving the contradiction between fluid flow capability and seal reliability
Solution Approach 2:
The seal is designed as a flexible element that can axially shift during operation. This flexibility allows the seal to move during reverse hydraulic fluid flow while the retractable guard member constrains radial extrusion, enabling both fluid flow and reliability
2Reliability
If the seal is constrained to prevent extrusion, then reliability is improved, but axial movement for fluid flow may be restricted
Solution Approach 1:
The sealing assembly is segmented into distinct functional components: the axially movable seal and the radially positioned retractable guard member. This segmentation allows the seal to move axially for fluid flow while the guard member independently prevents radial extrusion, maintaining both reliability and operational flexibility
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 enhances the reliability and longevity of the piston seal assembly by preventing seal extrusion and ensuring consistent sealing performance under varying hydraulic pressures, reducing the risk of malfunction and extending the assembly's lifespan.
Implementation Method 1
The piston moves in the axial direction along a housing or a shaft via hydraulic fluid pressure
Implementation Method 2
The seal is engaged with the shaft or the housing via an interference fit
Implementation Method 3
the seal is axially movable between the piston and the plate via hydraulic fluid pressure
Data Source
AI summary
A piston seal assembly including a piston, plate, and seal is provided. The piston is slidably supported on a shaft or in a housing, and includes a recess on an inner or outer radial portion. The plate is fastened to the piston and extends at least partially adjacent to the recess. The seal is located at least partially within the recess of the piston. The seal includes a radial sealing surface that engages the shaft or the housing, and the seal is axially movable between the piston and the plate via hydraulic fluid pressure.