Drilling Apparatus Torque Transmission via Eccentric Rotor and Torsion Rod
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Solution Overview
Problem
Down-hole drilling motors face challenges in transmitting torque through limited space and harsh environments, where drilling fluid erosion of drive components is exacerbated by axial misalignment and tortuous fluid flow paths.
Innovation Solution
The drilling apparatus incorporates a power section with a rotor that moves with eccentric rotary motion, a power transmission shaft that converts this motion to concentric rotation, and a torsion rod that transmits torque to a mandrel, ensuring efficient torque transmission while minimizing component erosion through an annular fluid flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If torque is transmitted through drive components in limited space with axial misalignment, then the drilling apparatus can operate in confined boreholes, but the drive components suffer from increased erosion due to tortuous fluid flow paths
Solution Approach 1:
The patent extracts the drilling fluid flow path from the drive component interior by implementing a separate annular flow channel between the drive shaft and housing. This separation removes the harmful interaction between drilling fluid and drive components, eliminating erosion while maintaining compact design.
Solution Approach 2:
The patent introduces an annular flow channel as an intermediary space between the drive shaft and housing. This intermediary channel directs drilling fluid flow away from the drive components, serving as a protective mediator that prevents direct contact and erosion while still allowing torque transmission through the drive shaft.
2Device complexity
If drive components are exposed to drilling fluid flow for power transmission, then the motor can be compact, but the drilling fluid erodes the drive components
Solution Approach 1:
The patent segments the internal volume into two distinct functional zones: an inner region for torque transmission through the drive shaft and an outer annular region for drilling fluid flow. This segmentation allows simultaneous achievement of compact design and erosion protection by separating fluid exposure from drive components.
Solution Approach 2:
The patent converts the potentially harmful drilling fluid flow into a beneficial cooling and cleaning mechanism by directing it through the annular channel. The flow that would otherwise erode components is redirected to serve the drive shaft without direct contact, transforming a harmful factor into a protective one.
3Productivity
If the power transmission shaft is constrained to concentric rotation, then torque transmission is efficient, but axial misalignment between drive components must be accommodated
Solution Approach 1:
The patent employs a universal joint at the connection between drive shaft and mandrel, allowing dynamic adaptation to axial misalignment. The universal joint provides rotational degrees of freedom that accommodate misalignment while maintaining efficient torque transmission, combining the benefits of constrained concentric rotation with adaptability.
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
This design effectively transmits torque to the drill bit while reducing component erosion and accommodating limited space, ensuring reliable operation in harsh drilling conditions.
Implementation Method 1
a rotor, and the rotor is adapted to move with eccentric rotary motion with respect to the longitudinal axis in response to the passage of drilling fluids through the power section
Implementation Method 2
A generally rigid torsion rod has an upper end and a lower end. The upper and lower ends of the torsion rod are constrained to rotate in a concentric manner with respect to the longitudinal axis, and the upper end of the torsion rod is coupled to the lower end of the power transmission shaft such that a torque may be transmitted from the power transmission shaft to the torsion rod
Data Source
AI summary
A drilling apparatus includes a housing that defines a longitudinal axis. A power section of the apparatus includes rotor adapted to move with eccentric rotary motion with respect to the longitudinal axis in response to the passage of drilling fluids through the power section. A power transmission shaft has an upper end coupled to the rotor and movable with the eccentric motion of the rotor, and a lower end constrained to rotate in a concentric manner with respect to the longitudinal axis. A generally rigid torsion rod has upper and lower ends constrained to rotate in a concentric manner, and the upper end of the torsion rod is coupled to the lower end of the power transmission shaft. A mandrel including a connection for a drill bit is interconnected with the lower end of the torsion rod such that a torque may be transmitted from the torsion rod to the mandrel to drive a drill bit.