Drilling Tool Bearing and Drivetrain Assembly Fatigue Reduction

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Solution Overview

Problem

Mud motors in drilling operations face premature fatigue failures due to high stress points, particularly at housing connections, which are predictable sources of failure and increase servicing costs.

Innovation Solution

A cartridge system of mounting is used to assemble bearings and the drivetrain into a loadable rotor assembly, eliminating high-failure housing connections and allowing service access, while retaining the assembly within a power section stator that is designed to withstand drilling loads without bending stress, thus reducing fatigue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If housing connections are used to assemble the mud motor, then the structure can be built, but fatigue failures occur at these connections under high stress

Engineering Contradiction:
Improvehousing connection strengthVSAvoidfatigue endurance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent removes the housing connections entirely from the design. The rotor assembly is retained within the stator using a retaining assembly at one end, eliminating the problematic housing connections that were sources of fatigue failure under high stress and bending loads.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mud motor is divided into separate components: the rotor assembly can be independently retained and serviced within the stator. This segmentation allows the rotor assembly to be removed and replaced without replacing the entire housing, improving maintenance efficiency.

Inventive Principle:
Principle #1Segmentation

2Strength

If traditional housing connections are used, then structural integrity is maintained, but servicing cost increases due to premature failures

Engineering Contradiction:
Improvestructural integrityVSAvoidservicing cost
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The rotor assembly is designed as a separable component that can be independently serviced. The retaining assembly allows the rotor to be removed from the stator for maintenance or replacement without damaging or replacing the housing structure, significantly reducing servicing costs.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the rotor assembly is retained within the stator, then fatigue is reduced, but service access must be enabled

Engineering Contradiction:
Improvefatigue resistanceVSAvoidservice accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The retaining assembly is designed to allow easy removal of the rotor assembly from the stator. This provides service access while maintaining the fatigue-resistant design, as the rotor can be extracted for maintenance without compromising the structural integrity of the housing connections.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3201418B1Drilling tool bearing and drivetrain assembly
Publication Date: 2020.04.08 HALLIBURTON ENERGY SERVICES INC
  • EP3201418B1 patent drawingFigure 1
  • EP3201418B1 patent drawingFigure 2A~2B
  • EP3201418B1 patent drawingFigure 3

AI summary

A downhole drilling motor, system, and method for using same are disclosed. A downhole drilling motor can include a power section stator having a first end, a second end, an internal cavity passing therethrough. The downhole drilling motor can further include a rotor assembly positioned and fully encased in the internal cavity. The rotor assembly includes a power section rotor, a drivetrain operably coupled to the power section rotor and a bearing set. The power section rotor is positioned at the first end within the internal cavity of the power section stator. The power section rotor, the drivetrain, and the bearing set are fully encased in the internal cavity of the power section stator. Additional apparatuses, systems, and methods are disclosed.