Splined Threaded Connection for Torque and Axial Load Transfer
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Solution Overview
Problem
Threaded connections used in hydrocarbon production often fail to balance torque transmission with the need for axial load support and volume for steering equipment in rotary steerable tools, leading to issues like thread stripping and limited strength.
Innovation Solution
A system comprising a male component with longitudinal splines and a middle element with both splines and a threaded section, which engages a female component, allowing for a robust connection that transfers torque, tension, and compression loads while maximizing volume for steering equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If threaded connections are used to connect male pin to female box, then axial tensile and compression forces can be withstood, but torque transmission capacity is limited and thread stripping may occur
Solution Approach 1:
The connection system is divided into three distinct components: a male component with longitudinal splines, a middle element with both splines and threaded section, and a female component with threaded box. This segmentation allows each component to specialize in specific functions - the splines handle torque transmission while the threaded section handles axial loads, resolving the contradiction between torque and axial load capacity.
Solution Approach 2:
The middle element merges two connection mechanisms into one component: longitudinal splines for torque transmission and a threaded section for axial load engagement. This combining allows the system to simultaneously achieve high torque transmission capacity through the splined interface and axial load capacity through the threaded engagement, eliminating the need to choose between the two connection types.
2Strength
If splines are used to transfer torque, then torque transmission is effective, but axial loads cannot be transferred
Solution Approach 1:
The middle element combines both splined interface and threaded section into a single component, allowing it to simultaneously transfer torque through the splines and axial loads through the threaded engagement with the female component, thus resolving the limitation of splines alone.
Solution Approach 2:
The middle element serves multiple functions: it engages with the male component's splines to transmit torque, engages with the female component's threaded section to transfer axial loads, and provides a unified interface for both connection types. This multi-functionality allows a single component to handle both torque and axial load transmission effectively.
3Strength
If a larger thread diameter is used for enhanced torque capacity, then the volume for steering equipment is reduced
Solution Approach 1:
By separating torque transmission (via splines) from axial load transmission (via threads), the system can use a smaller, more efficient spline interface for torque that occupies less radial space than a large-diameter threaded connection would require, thereby preserving volume for steering equipment.
Solution Approach 2:
The invention changes the connection parameter from relying solely on thread diameter for torque capacity to using spline geometry (number of splines, spline depth, spline profile) for torque capacity. This parameter change allows for more efficient torque transmission with reduced radial dimensions, freeing up space for steering equipment while maintaining or enhancing torque capacity.
Data Source
AI summary
A system for connecting a male component to a female component comprises a male component comprising a main body including a first compression face, a first tension face, and an outer surface that includes a plurality of first longitudinal splines; a middle element including an inner surface, an outer surface, and a second tension face configured to engage the first tension face, the inner surface including a plurality of second longitudinal splines corresponding to and engaging the first longitudinal splines so as to form a splined interface and the outer surface including a threaded section; and a female component defining a box, the box including a second compression face for engaging the first compression face and an inner wall that includes a wall threaded section corresponding to and engaging the middle element threaded section. The middle element may comprise a plurality of azimuthal segments.