Hydraulic Buffer Seal Back-Up Ring for Abrasive Groove Wear
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Solution Overview
Problem
Hydraulic cylinder seals in heavy machinery are prone to damage and failure due to abrasive contaminants and aggressive applications, leading to leaks and contamination, as the annular grooves in the cylinder head wear out over time.
Innovation Solution
A seal assembly comprising an annular buffer seal with a chamfered back-up ring that extends along the radial extent of the seal, reducing wear and enhancing the sealing performance by distributing contact forces and accommodating varying pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional seals are used in aggressive mining applications, then the sealing function is initially effective, but the annular grooves wear out quickly due to abrasive contaminants
Solution Approach 1:
The buffer seal acts as an intermediary component between the piston rod and the annular groove. It absorbs the harmful abrasive contaminants and prevents them from directly contacting and wearing the annular groove, thereby protecting the groove while maintaining sealing effectiveness
Solution Approach 2:
The buffer seal is designed as a sacrificial component that can be easily replaced. It intentionally wears instead of the expensive annular groove, providing a cost-effective solution where a cheaper component absorbs the wear damage in aggressive mining environments
2Reliability
If seals engage directly with the annular groove in abrasive environments, then sealing is achieved, but contaminants become imbedded and cause grinding wear
Solution Approach 1:
The buffer seal converts the harmful effect of abrasive contaminants into a beneficial protective function. By allowing contaminants to affect the buffer seal instead of the main seal and annular groove, the harmful abrasion is redirected to a replaceable component, protecting the critical sealing surfaces
Solution Approach 2:
The buffer seal serves as a protective intermediary layer that prevents direct contact between abrasive contaminants and the main seal assembly. It absorbs the contaminant impact and protects the sealing surfaces from grinding wear and contamination imbedding
3Ease of manufacture
If a simple seal design is used, then manufacturing is easy, but the seal fails in aggressive applications
Solution Approach 1:
The sealing system is segmented into multiple functional components: the buffer seal for contaminant protection, the back-up ring for structural support, and the main seal for primary sealing. This segmentation allows each component to be optimized for its specific function while maintaining overall manufacturing simplicity
Solution Approach 2:
The seal assembly uses composite construction with different materials optimized for specific functions - the buffer seal uses material resistant to abrasive wear, the back-up ring uses structurally strong material, and the main seal uses material optimized for sealing. This composite approach enhances durability without significantly complicating manufacturing
Data Source
AI summary
A seal assembly for a hydraulic cylinder piston rod of a hydraulic cylinder includes an annular buffer seal having a first axial pressure side configured to face a rod end chamber of the hydraulic cylinder and fit adjacent a first axial side surface of an annular groove defined in a cylinder head at the rod end of the hydraulic cylinder through which the piston rod passes, and a second axial seal side opposite from the first axial pressure side. An annular, disk-shaped back-up ring is configured to extend along an entire radial extent of the second axial seal side of the annular buffer seal and be axially positioned in between the annular buffer seal and a second axial side surface of the annular groove.