Hardened Backup Ring for Roller Cone Drill Bit Face Seal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The backup ring in roller cone drill bit face seal systems often fails due to tearing and wear from drilling fluids, particularly at the outer diameter, leading to seal failure and ingress of debris.
Innovation Solution
The backup ring is designed with increased hardness and material removal patterns such as U- or V-shaped edges, or electron beam radiation to enhance edge density, combined with optional springs or honeycomb structures to maintain flexibility and durability, ensuring effective sealing and contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the backup ring is made harder to resist wear from drilling fluids, then durability is improved, but the contact pressure on the face seal components increases excessively
Solution Approach 1:
The backup ring features a hardened outer surface layer (approximately 0.002 to 0.006 inches thick) with Shore A hardness of 60-80, while the inner core remains softer (Shore A 40-60). This local quality differentiation provides wear resistance at the sealing interface while maintaining flexibility and appropriate contact pressure in the bulk material.
Solution Approach 2:
The backup ring is constructed as a composite structure combining a hardened surface layer with a softer inner core. This composite material approach allows the surface to resist wear from abrasive drilling fluids while the softer core maintains elasticity and provides appropriate contact pressure without excessive hardness.
2Reliability
If the backup ring material is made more flexible to maintain sealing force, then sealing efficiency is improved, but wear and tear from abrasive drilling fluids increases
Solution Approach 1:
The backup ring has a hardened outer surface (Shore A 60-80) that contacts the drilling fluids and cutting elements, providing wear resistance, while the inner core remains softer (Shore A 40-60) to maintain flexibility and sealing force. This local quality gradient resolves the contradiction between sealing efficiency and wear resistance.
Solution Approach 2:
The composite structure combines a wear-resistant hardened surface layer with a flexible softer inner core. The hardened surface protects against abrasive damage from drilling fluids, while the flexible core maintains the necessary sealing force and conforms to surface irregularities.
3Ease of operation
If material is removed from the exposed end face to reduce force transmission, then flexibility is improved, but structural integrity may be compromised
Solution Approach 1:
The backup ring features segmented or patterned removal of material from the exposed end face, creating a non-uniform structure with retained support areas. This segmentation allows flexibility and stress relief in certain regions while maintaining structural integrity through strategically retained material zones.
Solution Approach 2:
Material removal is applied locally and non-uniformly to the exposed end face, creating zones of different structural properties. Areas with material removal provide flexibility and stress relief, while areas with retained material maintain structural integrity and support the ring's overall strength.
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 significantly reduces wear and tear, enhancing the durability of the backup ring and maintaining sealing efficiency even in abrasive drilling environments.
Implementation Method 1
increase the edge density of all or part of the exposed edges while leaving the interior portions unaffected by using electron beam radiation to increase the crosslink density
Data Source
AI summary
A backup ring for a face seal in a roller cone bit is configured to resist wear from drilling fluids present adjacent exposed faces of the backup ring. Portions are removed from an exposed end face in a variety of shapes while the hardness of the material is increased. The removal of material offsets an increase in force that would be transmitted through the backup ring on face seal assembly due to flexing. A spring can optionally be included in the removed material location. Another way is to increase the edge density of all or part of the exposed edges while leaving the interior portions unaffected by using electron beam radiation to increase the crosslink density or by other techniques that allow a unitary structure with a more durable edge region.