Downhole Tool Rotational Drive Coupling Torque Limiting
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Solution Overview
Problem
In downhole operations, existing rotational drive couplings can inadvertently transmit excessive torque, leading to damage or operational delays due to unplanned changes in fluid pressure, which is not effectively mitigated by current technologies.
Innovation Solution
A downhole tool with a rotatable inner and outer sleeve coupling system that can selectively transmit torque within a predetermined range, featuring a torque limiter mechanism to prevent transmission above a predetermined threshold, allowing reconfiguration between torque transmission and prevention configurations without requiring rotational alignment of the sleeves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fluid pressure controlled drive coupling is used, then torque transmission can be controlled, but inadvertent coupling or decoupling may occur due to unplanned fluid pressure changes
Solution Approach 1:
The patent introduces a mechanical intermediary mechanism (the coupling mechanism with protrusion and recess features) that mediates between the inner and outer sleeves. This mechanical intermediary provides stable torque transmission while preventing inadvertent coupling/decoupling through its designed engagement features that require intentional actuation to engage or disengage.
Solution Approach 2:
The patent replaces the fluid pressure controlled system with a mechanical coupling system that uses mechanical features (protrusions, recesses, and retaining features) to control torque transmission. This mechanical substitution eliminates the reliability issues of fluid pressure control by using positive mechanical engagement instead of pressure-dependent control.
2Productivity
If torque transmission is permitted without limitation, then rotational drive can be transmitted effectively, but excessive torque may damage the tool or associated equipment
Solution Approach 1:
The patent implements a dynamic coupling mechanism that can adapt its torque transmission characteristics. The coupling features are designed to engage fully for normal torque transmission but can disengage or limit engagement when excessive torque is applied, protecting the tool while maintaining productivity under normal operating conditions.
Solution Approach 2:
The patent incorporates protective features in advance within the coupling mechanism design. The retaining features and engagement geometry are pre-configured to prevent excessive torque from reaching vulnerable components, providing beforehand protection against damage before it can occur.
3Manufacturing precision
If the coupling portions require rotational alignment for engagement, then precise torque transmission is achieved, but complex alignment procedures are required
Solution Approach 1:
The patent employs asymmetric coupling features (protrusions and recesses with specific geometries) that guide the inner and outer sleeves into proper alignment during assembly. The asymmetric design provides self-alignment capabilities, ensuring precise torque transmission while simplifying the assembly process and eliminating complex alignment procedures.
Data Source
AI summary
A downhole tool (10) comprising rotatable inner and outer sleeves (62, 63). The sleeves (62, 63) comprise coupling portions for transmitting a torque between the sleeves (62, 63). The tool is reconfigurable between a first configuration whereby the coupling portions are axially misaligned to prevent transmission of torque between the inner and outer sleeves (62, 63), and a second configuration whereby the coupling portions are axially aligned to permit a transmission of torque between the sleeves (62, 63). At least one of the coupling portions is configured to prevent the transmission of torque above a predetermined torque threshold.