Drill String Plug Connection Geometry for High-Load Torque Transfer
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Solution Overview
Problem
Existing plug connections for earth drill strings face challenges in providing sufficient strength and durability under high loads while minimizing wear, particularly in soil drilling applications.
Innovation Solution
The design of a plug connection for earth drill strings featuring a cross-section with at least one circular section and one more straight-edged section, allowing for torque transmission through the straight-edged section, while the circular section is not involved, and incorporating a locking element contact surface on a separate section, enabling efficient force and torque distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional circular cross-section is used for the connector plug/socket, then the design is simple and manufacturing is easy, but the strength and wear resistance under high loads is insufficient
Solution Approach 1:
The connector cross-section is designed with asymmetric features including flat sections, chamfers, and keyways that break the circular symmetry. This asymmetric design provides specific engagement surfaces for torque transmission and locking mechanisms, significantly improving strength and wear resistance under high loads while maintaining manufacturability through standard machining operations.
Solution Approach 2:
The connector cross-section is segmented into distinct functional zones: circular sections for general structural integrity, flat sections for torque transmission, chamfered sections for engagement, and keyway sections for locking. This segmentation allows each zone to optimize its specific function while collectively providing enhanced overall performance.
2Adaptability or versatility
If a purely square cross-section is used for the connector, then torque transmission is maximized, but additional space is lost that could be used for routing or channels
Solution Approach 1:
The connector cross-section applies local quality by providing flat sections and chamfers specifically at the periphery for torque transmission and engagement, while the central circular portion remains intact to provide structural strength. This localized optimization allows internal space to be utilized for routing channels without compromising the torque transmission capability at the critical engagement surfaces.
3Ease of manufacture
If the locking element contact surface is positioned at the center of the connector, then the contact surface area is maximized, but the design complexity and manufacturing difficulty increase
Solution Approach 1:
The locking element contact surface is extracted from the central position and relocated to the periphery of the connector cross-section, specifically on the flat sections. This extraction simplifies manufacturing by positioning the contact surface on accessible outer surfaces that are easier to machine and assemble, while still providing sufficient contact area for effective locking through the optimized flat section geometry.
Data Source
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AI summary
The invention relates to a section of a drill string, wherein the section of the drill string is designed at its end to form a plug connection and has at least one end (a) a connector plug or (b) a connector socket, wherein the connector plug has on the outside or the connector socket has on the inside at least one circular section and at least one more straight section in cross-section.