Stackable Thrust Bearing Assembly for Downhole Motor Axial Load Distribution
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Solution Overview
Problem
Existing downhole drilling motors face challenges with complex and inflexible thrust bearing assemblies that lead to undesirable force concentrations and reduced lifetime of drive shafts due to steps or shoulders, making them less adaptable for various drilling operations.
Innovation Solution
A configurable bearing assembly using multiple stackable thrust bearings, spacers, and spring components to distribute axial loads evenly, minimizing wear and stress concentrations, and a drive shaft cap to prevent rotation and maintain compression, thereby enhancing the bearing assembly's durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If existing thrust bearing assemblies are used, then axial forces can be dissipated, but the system complexity increases and adaptability decreases
Solution Approach 1:
The bearing assembly is divided into modular components including multiple thrust bearings, spacers, and seals that can be independently selected and arranged. This segmentation allows the system to handle axial forces while maintaining simplicity and adaptability through modular configuration rather than a monolithic complex assembly.
Solution Approach 2:
The bearing assembly design incorporates universal features that allow it to accommodate different drilling conditions and motor configurations. The modular thrust bearings and spacers can be arranged in various configurations to handle different axial load requirements, making the assembly adaptable to multiple applications without requiring completely different designs.
2Reliability
If steps or shoulders are added to the drive shaft for bearing engagement, then bearing support is improved, but force concentrations increase and shaft lifetime decreases
Solution Approach 1:
Instead of creating abrupt geometric discontinuities with steps or shoulders, the design distributes the bearing engagement area along the drive shaft. The thrust bearings engage with the shaft in a manner that spreads localized forces over a longer axial distance, maintaining adequate bearing support while avoiding stress concentration points that would reduce shaft lifetime.
Solution Approach 2:
The bearing assembly allows for axial movement and adjustment of the thrust bearings relative to the drive shaft. This dynamic capability enables the bearings to self-adjust to minor shaft deflections and vibrations during operation, maintaining continuous contact and force distribution without requiring rigid fixed positions that would create stress concentrations.
3Device complexity
If a single thrust bearing configuration is used, then the design is simple, but adaptability to various drilling operations is reduced
Solution Approach 1:
The thrust bearing assembly uses multiple individual thrust bearings that can be stacked and arranged in different configurations. This segmentation allows the same basic modular components to be adapted to various axial load requirements and drilling applications by simply changing the number and arrangement of bearings, maintaining design simplicity while achieving versatility.
Solution Approach 2:
The bearing assembly incorporates adjustable elements including spacers and seals that can be repositioned to accommodate different operating conditions. This dynamic adjustability allows a single basic design to adapt to various drilling operations with different axial load characteristics without requiring completely different bearing configurations.
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 allows for improved handling of axial loads, maintaining equal wear on stackable bearings, reducing stress concentrations, and increasing the lifetime and efficiency of the downhole drilling motor by distributing forces effectively and preventing over-torque.
Implementation Method 1
spring components to distribute axial loads evenly
Data Source
AI summary
A bearing assembly for a downhole motor is provided. The bearing assembly includes a housing and a drive shaft designed to rotate with respect to the housing. The bearing assembly also includes stackable thrust bearings, each pre-loaded via a corresponding spring component. Some thrust bearings are arranged such that their spring components distribute axial loads from the housing in a first direction to the thrust bearings. Other thrust bearings are arranged such that their spring components distribute axial loads from the drive shaft in the first direction to the thrust bearings. Thus, the bearing assembly may be tailored via the stackable bearings to distribute axial thrust forces on the downhole motor evenly across the different thrust bearings. The bearing section may include a machinable spacer used to provide a double shouldered connection between the drive shaft and a drive shaft cap used to compress the stackable bearings.