Roller Bearing Assembly for Drill Hammer Side Load Management
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Solution Overview
Problem
Down-the-hole drill hammers with internal roller bearing assemblies have a short lifespan due to their inability to handle substantial side loads, leading to increased maintenance and reduced operational efficiency.
Innovation Solution
A roller bearing assembly is introduced that circumscribes the drill bit, comprising a race and a plurality of rollers, where the race is connected to the housing and includes circumferential recesses to engage the rollers, allowing for rolling engagement and reducing friction and wear, with the rollers being positioned distally from the impact surface and splines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional internal bearings are used for maintaining drill bit alignment, then axial alignment is achieved, but the bearing cannot handle substantial side loads leading to short lifespan
Solution Approach 1:
The patent replaces conventional sliding journal bearings with a roller bearing assembly. This substitution changes the mechanical interaction from sliding friction to rolling friction, where rollers circumscribe the drill bit and engage with a race. The rollers are arranged to handle both axial and radial (side) loads simultaneously, resolving the contradiction between alignment capability and side load capacity.
Solution Approach 2:
The roller bearing assembly utilizes cylindrical rollers that circumscribe the drill bit, creating a curved contact surface. This spherical/cylindrical geometry allows the bearing to accommodate radial and axial loads from multiple directions, enabling the bearing to handle substantial side loads while maintaining drill bit alignment, thereby extending bearing lifespan.
2Reliability
If roller bearing assembly is introduced to handle side loads, then bearing lifespan is extended, but device complexity increases
Solution Approach 1:
The roller bearing assembly is designed to perform multiple functions simultaneously: it maintains axial alignment of the drill bit, handles substantial side loads, and reduces friction through rolling contact. By consolidating these functions into a single integrated assembly rather than using separate components, the patent extends bearing lifespan while minimizing the increase in device complexity.
Solution Approach 2:
The roller bearing assembly features rollers nested within a race that is connected to the housing. The rollers circumscribe the drill bit and are contained within the race structure, creating a compact nested arrangement. This nested design achieves the multi-functional requirements without proportionally increasing overall device complexity.
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 roller bearing assembly significantly extends the life expectancy of the drill hammer by reducing wear and tear, allowing it to operate at greater depths with reduced maintenance needs, as demonstrated by drilling experiments showing 50% less wear compared to conventional journal bearings.
Implementation Method 1
a roller bearing assembly circumscribing the drill bit. The roller bearing assembly includes a race and a plurality of rollers operatively engaged with the race
Implementation Method 2
allowing for rolling engagement and reducing friction and wear
Data Source
AI summary
A down-the-hole drill hammer is provided that includes a housing, a drill bit proximate a distal end of the housing, and a roller bearing assembly. The roller bearing assembly circumscribes the drill bit. The roller bearing assembly includes a race and a plurality of rollers. The plurality of rollers are operatively engaged with the race.