Drill Bit Retaining Assembly Fluid Pathway Design
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Solution Overview
Problem
Conventional down-the-hole hammer drill bit retaining assemblies compromise drill bit retention due to reduced area contact with the abutment shoulder, as they divert pressurized fluid to the drive sub splines, weakening the retention and reducing the effective area for fluid delivery to the splines.
Innovation Solution
A retaining assembly with a drive sub and retainer ring configuration that allows a fluid flow pathway over the radially external surface of the retainer ring, directing fluid to the drive sub splines while maximizing surface area contact with the drill bit shoulder, ensuring secure retention and efficient fluid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the retainer ring includes flow path channels to deliver lubricating fluid to the drive sub splines, then the fluid delivery is improved, but the area contact of the ring with the abutment shoulder is reduced, weakening the drill bit retention
Solution Approach 1:
The invention moves the fluid flow pathway from the radially inner region (through the retainer ring wall) to the radially outer region (along the external surface). This dimensional relocation allows the retainer ring to maintain full radial thickness for structural strength while still providing fluid delivery paths on its outer surface that do not compromise the abutment contact area.
Solution Approach 2:
The invention segments the retainer ring into distinct functional zones: the radially inner region maintains solid structure for maximum abutment contact and retention strength, while the radially outer surface incorporates fluid flow pathways for lubrication delivery. This segmentation allows each region to optimize its specific function without compromising the other.
2Quantity of substance
If the retainer ring has reduced area contact with the abutment shoulder to allow fluid flow, then the fluid delivery volume is improved, but the retention strength is weakened
Solution Approach 1:
The invention relocates fluid flow pathways to the radially outer surface of the retainer ring, utilizing the external surface area rather than compromising the internal abutment contact area. This allows increased fluid volume delivery through multiple external pathways while the retainer ring maintains full structural integrity at the abutment interface.
Solution Approach 2:
The invention applies different functional qualities to different regions of the retainer ring: the radially inner region maintains high structural quality for maximum abutment contact and retention strength, while the radially outer surface incorporates fluid flow channels for lubrication delivery. Each region is optimized for its specific function without compromising the other.
3Reliability
If conventional retainer rings are used without flow channels, then the retention strength is maintained, but the lubricating fluid cannot reach the drive sub splines effectively
Solution Approach 1:
The invention adds fluid delivery functionality by utilizing the radially outer surface dimension of the retainer ring, which does not interfere with the radially inner abutment contact function. This allows the retainer ring to simultaneously provide both strong retention and effective lubrication delivery.
Solution Approach 2:
The invention makes the retainer ring multi-functional by incorporating both retention function (through abutment contact at the radially inner region) and fluid delivery function (through pathways on the radially outer surface). This eliminates the need for separate retention and lubrication components.
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 provides strong and reliable retention of the drill bit while enabling the desired volume of lubricating fluid to reach the drive sub splines, enhancing drilling efficiency and reducing wear on the drive sub splines.
Implementation Method 1
a piston that is capable of shuttling axially between the top sub and the drill bit and is driven by the pressurised fluid to strike a rearward anvil end of the bit
Implementation Method 2
The fluid acts to both drive the hammer drilling action and to flush rearwardly dust and fines resultant from the cutting action, rearwardly through the bore hole
Implementation Method 3
enabling delivery of a desired volume of lubricating fluid to the splines
Data Source
AI summary
A down-the-hole hammer drill bit retaining assembly is arranged to releasably retain a drill bit at a hammer arrangement of a percussion drilling apparatus. The retaining assembly includes a drive sub and a retainer ring. The drive sub has at least one indent to provide a fluid communication pathway for a flushing fluid extending over a radially outward facing surface of the retainer ring and into an internal region of the drive sub in contact with inwardly projecting splines.