Magnetostrictive Linear Actuator for Downhole Drive Units
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Solution Overview
Problem
Existing drive units for downhole tools are mechanically complex, costly to manufacture, and require frequent maintenance due to their complexity and numerous components such as filters, flow restrictors, and pressure relief valves.
Innovation Solution
A compact, mechanically-actuated drive unit utilizing a magnetostrictive linear actuator with a support structure to compensate for borehole parameters, which includes a coil and a ferromagnetic rod that elongates under a magnetic field, and a clamping mechanism to facilitate linear movement, potentially with thermal expansion matching and active cooling to maintain functionality in harsh environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional motor-driven piston pumps and ball screw spindles are used in drive units, then reliable force generation is achieved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent replaces conventional motor-driven piston pumps and ball screw spindles with a magnetostrictive linear actuator that uses magnetic field-induced material deformation to generate linear motion. The magnetostrictive element responds directly to magnetic fields, eliminating the need for complex mechanical linkages, motors, and hydraulic components while maintaining effective force generation capability.
Solution Approach 2:
The patent eliminates hydraulic systems with filters, flow restrictors, shut-off valves, and pressure relief valves by using direct magnetostrictive actuation. The magnetostrictive element provides direct mechanical actuation without requiring hydraulic fluid, pumps, or associated control components, thereby removing the entire hydraulic subsystem.
2Reliability
If conventional drive units with multiple components are used, then functional reliability is maintained, but maintenance frequency increases due to component wear
Solution Approach 1:
The patent replaces wear-prone mechanical components (motors, pumps, valves, seals) with a magnetostrictive actuator that has no moving mechanical parts. The magnetostrictive element undergoes controlled deformation in response to magnetic fields without mechanical contact or friction, eliminating wear and the associated maintenance requirements.
3Device complexity
If magnetostrictive linear actuators are used to reduce complexity, then device size is reduced, but thermal expansion effects become more significant in high temperature environments
Solution Approach 1:
The patent addresses thermal expansion effects by selecting magnetostrictive materials and support structure materials with matched thermal expansion coefficients. This ensures that both components expand at the same rate with temperature changes, maintaining precise dimensional relationships and actuator performance in high-temperature downhole environments.
Solution Approach 2:
The patent compensates for thermal effects by carefully selecting and matching material properties (thermal expansion coefficients) between the magnetostrictive element and support structure. This parameter matching ensures that thermal expansion does not disrupt the relative positioning or functional integrity of the actuator components.
4Ease of manufacture
If compact magnetostrictive actuators are used, then manufacturing cost decreases, but control precision requirements increase due to smaller scale effects
Solution Approach 1:
The patent replaces imprecise mechanical control systems with direct magnetic field actuation of the magnetostrictive element. The magnetic field can be precisely controlled and distributed along the magnetostrictive element, enabling accurate positioning and control at compact scales without the mechanical tolerance and alignment issues inherent in smaller mechanical systems.
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 provides a smaller, more controllable, and reliable drive unit with reduced maintenance needs, capable of operating effectively in extreme downhole conditions, including high temperatures, by minimizing component complexity and enhancing operational efficiency.
Implementation Method 1
a magnetostrictive linear actuator with a support structure to compensate for borehole parameters, which includes a coil and a ferromagnetic rod that elongates under a magnetic field
Data Source
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AI summary
An apparatus to be conveyed into a wellbore is provided, wherein the apparatus includes a housing configured to be conveyed downhole and a drive member located in the housing. The apparatus further includes a drive unit configured to actuate movement of the drive member by selectively coupling to the drive member, wherein the coupling of the device to the drive member is controlled by applying an energy to a selected material in the device.