Helical Thread Rotation Tool for Downhole Linear Motion Conversion
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Solution Overview
Problem
Current mechanical rotation tools for down-hole applications, such as coil tubing fishing and pipeline cleaning, are inefficient in converting linear motion to rotational motion, requiring multiple axial strokes for a single 360-degree revolution and lacking hydraulic disconnect functionality.
Innovation Solution
A gear shaft with an external helical thread is surrounded by a housing with a tubular gear and face gear mechanism, allowing for selective engagement and disengagement during downward and upward strokes, utilizing a compression spring to bias the tube gear for efficient rotational movement conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mechanical rotation tools use J-slot design to translate axial motion to rotational motion, then rotation can be achieved, but multiple axial strokes are required for a single 360-degree revolution resulting in low productivity
Solution Approach 1:
The rotation mechanism is segmented into distinct functional components: a gear shaft with external helical thread, a tubular gear with internal helical thread, and a face gear with teeth. This segmentation allows each component to perform a specific function in the motion conversion process, enabling more efficient translation of axial motion to rotational motion compared to the integrated J-slot design.
Solution Approach 2:
The patent employs helical threads on both the gear shaft and tubular gear, creating a curved engagement path that continuously converts axial motion to rotational motion. The helical curvature allows for smooth, continuous rotation rather than the discrete step-by-step rotation achieved by J-slot design, significantly improving rotation efficiency.
2Adaptability or versatility
If conventional rotation tools are designed for mechanical operation, then they can function in down-hole applications, but they lack hydraulic disconnect functionality reducing adaptability
Solution Approach 1:
The rotation tool is designed with multi-functionality by integrating both mechanical operation capabilities and hydraulic disconnect functionality. The tool can operate mechanically through the gear shaft and gear mechanism while also accepting hydraulic actuation for disconnect operations, making it adaptable to various down-hole applications and work strings.
Solution Approach 2:
A hydraulic port is provided in the gear shaft, serving as an intermediary that allows hydraulic fluid to pass through the rotating component. This enables hydraulic actuation of disconnect mechanisms without interfering with the mechanical rotation function, facilitating versatile operation in different down-hole scenarios.
3Ease of operation
If face gear teeth are designed to engage continuously, then rotational motion is continuously transmitted, but engagement on upward stroke causes unwanted rotation reducing control precision
Solution Approach 1:
The face gear teeth are designed with dynamic engagement characteristics that change based on the direction of motion. During downward stroke, the teeth are positioned to engage and transmit rotational motion. During upward stroke, the teeth are positioned to disengage, allowing the tubular gear to rotate freely without driving the face gear. This dynamic engagement/disengagement mechanism provides precise directional control.
Solution Approach 2:
The helical thread engagement between the gear shaft and tubular gear ensures continuous transmission of axial motion to rotational motion during the downward stroke. The face gear teeth maintain continuous engagement with the tubular gear teeth during rotation, ensuring smooth and controlled rotational output without interruption or backlash.
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 enables efficient conversion of linear to rotational motion, providing a 360-degree rotation for each inch of downward movement with directional control, enhancing the efficiency and functionality of down-hole tools like coil tubing fishing operations.
Implementation Method 1
A compression spring is disposed in the housing bore for biasing the tube gear structure toward the housing face gear
Implementation Method 2
The gear shaft has an external helical thread formed on at least a portion of its surface
Implementation Method 3
A tubular gear disposed within the housing has an internal, helical thread engaging the gear shaft thread
Implementation Method 4
The tubular gear further has a toothed face gear on its lower end for selective engagement with a corresponding face gear connected to the housing
Data Source
AI summary
A downhole rotation tool comprises a housing rotatable and axially slideable in relation to a gear shaft. The gear shaft is located interior of the housing. A tube gear is located intermediate the gear shaft and the housing. Helical threading on the gear shaft exterior interacts with helical threading interior of the tube gear to impart rotation of the tube gear upon linear movement of the gear shaft. A gear face at a lower end of the tube gear interacts with a corresponding gear face on the housing. Face gear teeth of the tube gear and the housing include axially-aligned engaging surfaces to rotate the housing in a preferred direction on downward stroke of the gear shaft and include inclined slip surfaces to allow relative rotation of the housing gear face and the tube gear face upon upward stroke of the gear shaft.