Zero Backlash Downhole Setting Tool with Segmented Wicker Threads
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Solution Overview
Problem
Traditional body lock rings in downhole drilling and completion tools suffer from backlash due to the finite distance between wicker threads, which can lead to slippage and loss of energy, particularly in sealing applications where it can be catastrophic.
Innovation Solution
A zero backlash downhole setting tool design that includes a mandrel, a body lock ring, a setting sleeve, a rotary take-up, and a follower housing, where the backlash is counteracted by changing the combined length of the rotary take-up and follower housing through a ratcheting mechanism and helical interface, allowing for effective anchoring and energy retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the peak-to-peak distance between wickers is reduced to reduce backlash, then backlash is reduced, but the tooth flank surface area is reduced which decreases holding ability and increases slippage potential
Solution Approach 1:
The body lock ring is divided into multiple wicker threads with different lead angles. The first wicker thread has a first lead angle optimized for one function, while the second wicker thread has a second lead angle optimized for another function. This segmentation allows each wicker thread to be independently optimized, resolving the contradiction by enabling different peak-to-peak distances or flank geometries for different functional requirements.
Solution Approach 2:
Different portions of the body lock ring have different wicker thread characteristics. Specifically, the first wicker thread has different geometric properties (lead angle, pitch, flank surface area) than the second wicker thread. This local quality variation allows the structure to optimize for both low backlash in certain regions and high holding ability in other regions, simultaneously addressing both contradictory requirements.
2Manufacturing precision
If the wicker thread geometry is optimized for minimal backlash, then positioning precision is improved, but the energy retention capability is reduced
Solution Approach 1:
The energy transmission and positioning functions are segmented across different wicker threads. The first wicker thread with its specific lead angle handles one aspect of energy transmission, while the second wicker thread with different geometry handles another aspect. This segmentation allows the system to achieve both precise positioning (through optimized pitch and lead angle) and energy retention (through adequate flank surface area in the second wicker thread).
Solution Approach 2:
The invention changes the geometric parameters of the wicker threads by providing at least two different lead angles. This parameter variation allows optimization of the first wicker thread for positioning precision (smaller pitch, specific lead angle) while the second wicker thread maintains parameters (larger flank surface area, different lead angle) that preserve energy retention capability, thus resolving the contradiction between positioning precision and energy retention.
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 tool effectively eliminates backlash, reducing the risk of slippage and energy loss, ensuring reliable operation of downhole tools by utilizing a ratcheting mechanism and helical interface to counteract backlash, thereby enhancing the holding ability and energy retention.
Implementation Method 1
a setting sleeve in force transferable communication with one or more resilient elements. The one or more resilient elements are in force transferable communication with the device to be set
Implementation Method 2
a rotary take-up in tensile force transmissive contact with the device to be set; and a follower housing configured to follow the rotary take-up
Data Source
AI summary
A zero backlash downhole setting tool including a mandrel; a body lock ring at the mandrel; a setting sleeve in operable communication with a device to be set; a rotary take-up in tensile force transmissive contact with the device to be set; and a follower housing configured to follow the rotary take-up in a first mode of operation and extend away therefrom in another mode of operation, the follower being engaged with the body lock ring and method.