Tilted Thrust Bearing for Earth Boring Bit
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Solution Overview
Problem
Existing rolling cone earth boring bits face issues due to slight misalignment of thrust faces, leading to concentrated load contact and reduced lubricant film effectiveness, which affects torque and bearing surface life.
Innovation Solution
The thrust faces of the bearing pin and cone are designed with a tilted portion relative to their axes, creating diverging and converging clearance areas to enhance lubricant film formation, reducing torque and contact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thrust faces are initially parallel to each other, then the structure is simple and easy to manufacture, but the misalignment during drilling concentrates thrust bearing contact loads which is detrimental
Solution Approach 1:
The invention applies asymmetry by tilting one thrust face relative to the other, creating a deliberate non-parallel configuration. This asymmetric design compensates for the natural misalignment that occurs during drilling, ensuring that the bearing surfaces remain properly aligned under load while maintaining manufacturing simplicity.
Solution Approach 2:
The invention changes the geometric parameter of the thrust face orientation from parallel (0 degrees) to a specific tilt angle. This parameter modification transforms the clearance pattern from uniformly distributed to deliberately converging, which improves load distribution and bearing surface life without significantly complicating manufacturing.
2Device complexity
If the thrust faces are initially parallel to each other, then the structure is simple, but the misalignment creates circumferentially converging-diverging space which concentrates thrust bearing contact loads
Solution Approach 1:
The asymmetric tilt of one thrust face creates a controlled converging clearance pattern that prevents harmful load concentration. By introducing this deliberate asymmetry, the design transforms the natural misalignment from a harmful effect into a beneficial load-distributing mechanism.
Solution Approach 2:
The invention converts the harmful effect of misalignment-induced converging clearance into a beneficial feature. By pre-tilting the thrust face, the design harnesses the converging clearance effect to improve load distribution and reduce contact stresses, turning what would normally be a detrimental phenomenon into an advantageous characteristic.
3Loss of energy
If the thrust faces are tilted relative to each other, then the lubricant film is enhanced and torque is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The invention modifies the geometric parameter of the thrust face angle from parallel to a specific tilt angle, which transforms the clearance pattern to create beneficial hydrodynamic effects. This parameter change reduces torque by improving lubricant film formation while establishing achievable manufacturing precision requirements for the tilt angle.
Solution Approach 2:
The invention utilizes hydrodynamic principles by creating a converging clearance space between the tilted thrust faces. This geometric configuration generates hydrodynamic pressure in the lubricant film, reducing friction and torque without requiring active hydraulic or pneumatic systems, thereby maintaining relatively simple manufacturing requirements.
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 tilted thrust faces improve lubricant film formation, reducing torque and enhancing the life of bearing surfaces by distributing load more evenly.
Implementation Method 1
This slight misalignment of the cone axis relative to the bearing pin axis results in a circumferentially converging-diverging space between the thrust faces, which can be beneficial because it can create hydrodynamic lubricant pressure between the thrust faces to help support the load.
Implementation Method 2
create hydrodynamic lubricant pressure between the thrust faces to help support the load
Data Source
AI summary
An earth boring bit has thrust faces with one of the thrust faces being at least partially tilted relative to the other. The bit has a cone rotatably mounted to a bearing pin of the bit body. The thrust faces are in the cone and on an end of the bearing pin. One of the thrust faces is completely flat and perpendicular to the axis of the bearing pin. The other thrust face has a tilted portion that is at a skewed angle relative to the axis. The tilted portion creates converging and diverging zones between the thrust faces.