Mud Motor Thrust Bearing Assembly for Higher Torque Transfer
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Solution Overview
Problem
Current thrust bearings in mud motors experience limited torque transfer capability due to slippage between bearing stacks, leading to wear and damage under harsh drilling conditions, including high pressures and temperatures, and high mechanical stresses.
Innovation Solution
A mud motor with a thrust bearing featuring a unitary inner race member with axially spaced inner races and enclosed ball sets, secured by outer races and support members, enhancing torque transfer and reducing failure rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple individual bearing stacks are axially abutted to form the thrust bearing, then the thrust bearing can support the drive shaft under high pressure and temperature conditions, but the torque transfer capability is limited due to slippage between bearing stacks
Solution Approach 1:
The patent combines multiple individual bearing stacks into a single unitary thrust bearing assembly with a common outer race. This merging eliminates the interfaces between separate bearing stacks, preventing slippage between stacks while maintaining the ability to support high pressures and temperatures. The unified structure allows for effective torque transfer from the drive shaft to the rotor without the friction losses that occur at the interfaces of multiple separate stacks.
2Ease of manufacture
If individual bearing stacks are used in the thrust bearing, then the structure can be assembled with standard components, but slippage between bearing stacks causes wear and damage to the thrust bearing and adjacent parts
Solution Approach 1:
The patent merges multiple bearing stacks into a unified assembly with a common outer race that houses all bearing elements. This eliminates the wear and damage problems caused by slippage between separate bearing stacks while maintaining ease of manufacture through modular assembly of the bearing elements within the common outer race structure.
3Temperature
If split races are used for each ball set in the thrust bearing, then the bearing can accommodate thermal expansion under high temperature, but the torque transfer capability is reduced due to friction contact between bearing stacks
Solution Approach 1:
The patent combines multiple bearing stacks into a single integrated thrust bearing assembly where the bearing elements are contained within a common outer race. This unified structure eliminates the friction contact between separate bearing stacks that occurs in split-race designs, thereby improving torque transfer efficiency while still accommodating thermal expansion through the integrated design.
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 new thrust bearing design improves torque transfer and reduces failures such as cracking and breakouts, providing enhanced durability under extreme drilling conditions.
Implementation Method 1
slippage (friction contact) between the bearing stacks
Data Source
Figure 1
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AI summary
An apparatus for use in a wellbore is disclosed that in one non-limiting embodiment includes a rotatable member, a thrust bearing coupled to the rotatable member, wherein the thrust bearing includes a bearing stack that further includes a unitary inner race member that includes a number of axially spaced inner races around an outer surface of the unitary inner race member. A set of bearing elements is placed in each inner race, and a separate outer race secures each set of bearing elements in each inner race.