Split Retainer Guide Ring Zero Kerf Downhole Stability
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Solution Overview
Problem
Downhole hammers and percussion tools face issues with fatigue breakage of lower housing and drill bit connection, leading to component loss and incomplete retention, with prior art split retaining rings experiencing radial movement, wear, and inadequate guidance due to significant kerf widths and loose tolerances.
Innovation Solution
A split retainer and guide ring design with minimal or zero kerf, fabricated from mild steel or similar materials, providing a solid engagement with the inner case and outer shank diameters, and featuring chamfered surfaces and openings to enhance stability and resistance to lateral displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional split retaining rings are used with significant kerf widths, then the ring can be assembled, but radial movement and instability occur during operation
Solution Approach 1:
The patent changes the critical parameter of kerf width from conventional significant widths to minimal or zero kerf. This is achieved through precise machining methods that reduce the gap between ring halves to near-zero, eliminating the radial play and instability that occurs with conventional wider kerfs while maintaining assembly capability
Solution Approach 2:
The patent employs hydraulic expansion during assembly to force the ring halves together with minimal kerf. Hydraulic pressure is applied to expand the ring into the tapered bore, causing the halves to close tightly around the drill bit shank with negligible gap, thereby achieving both assembly ease and operational stability
2Ease of manufacture
If loose tolerances are used for retainer ring fit, then assembly is easier, but radial movement and wear increase
Solution Approach 1:
The patent changes the tolerance parameter from loose conventional tolerances to tight precision tolerances on the order of thousandths of an inch. This precision machining eliminates radial movement and wear while the tapered bore design and hydraulic expansion process make assembly equally easy by providing self-aligning and force-closing mechanisms
3Stability of the object's composition
If tapered surfaces are added to split rings, then radial movement is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent merges the taper feature directly into the retainer ring structure itself, eliminating the need for separate taper components. The taper is machined as an integral part of the ring, and the hydraulic expansion process utilizes this taper to force the halves together, achieving radial stability without adding significant manufacturing complexity
Solution Approach 2:
The tapered bore and ring taper serve multiple functions simultaneously: they provide the mechanical interface for hydraulic expansion, create the closing force that reduces kerf to minimal dimensions, and establish the radial stability during operation. This multi-functionality eliminates the need for separate stabilization features
4Stability of the object's composition
If minimal kerf is achieved through precision machining, then ring stability improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent performs preliminary action by applying hydraulic expansion force during the assembly process to close the kerf to minimal dimensions. The hydraulic pressure forces the ring halves together against the tapered bore, achieving near-zero kerf at the moment of assembly rather than requiring the halves to be machined to exact dimensions beforehand
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
A retainer and guide ring includes a first ring half and a second ring half that when placed adjacent to one another forms a complete ring. The retainer and guide ring also includes a kerf that is formed between ends of each of the first and second ring halves, which ranges from about zero inches to about 0.010 inches. In some exemplary embodiments, the retainer and guide ring is formed by obtaining two identical rings and making a cut along an edge of the diameter on each ring thereby forming a larger ring arc and a smaller ring arc for each of the rings. The two larger ring arcs are used to form the retainer and guide ring. In another exemplary embodiment, the retainer and guide ring is formed by obtaining a single ring and making a cut along the diameter.