Curved Piston Liner for Rotary Steerable Drill Tools
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Solution Overview
Problem
Existing drill string steering systems face challenges with durability and maintenance, particularly in preventing wear and tear on components during drilling operations, as well as optimizing steering forces and reducing side loading on steering pads.
Innovation Solution
The integration of a piston liner with a curved channel and a pad retention housing allows for a stronger, more elastic material to be used for the housing while the piston liner is made of a hard, abrasion-resistant material, enabling the pad pushers to move without jamming and reducing wear, with a seal preventing direct contact between the piston and liner, thus enhancing steering control and ease of maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single material is used for both the piston liner and pad retention housing, then manufacturing is simpler, but the housing cannot be made stronger and more elastic while the piston liner cannot be made more abrasion-resistant
Solution Approach 1:
The system divides the piston assembly into separate components: a piston liner made of hard, abrasion-resistant material and a pad retention housing made of strong, elastic material. This segmentation allows each component to be optimized for its specific functional requirements without compromising the other, resolving the contradiction between manufacturing simplicity and material optimization.
Solution Approach 2:
The invention employs different materials for the piston liner and housing, creating a composite structure where the piston liner is made of hard, abrasion-resistant material while the housing is made of strong, elastic material. This composite approach allows simultaneous optimization of wear resistance and structural strength, addressing the contradiction between material performance and manufacturing complexity.
2Productivity
If the piston moves along a straight path, then the structure is simpler, but side loading occurs on the steering pads reducing steering efficiency
Solution Approach 1:
The piston liner incorporates a curved channel that guides the piston along a curved path rather than a straight line. This curvature is specifically designed to counteract side loading on the steering pads, optimizing the normal steering force throughout the pad's range of motion. The curved path eliminates steering inefficiencies while adding minimal structural complexity.
3Reliability
If the piston directly contacts the piston liner, then the structure is simpler, but wear and tear increases reducing component durability
Solution Approach 1:
A seal acts as an intermediary element between the piston and the piston liner, preventing direct contact between these two components. The seal reduces wear and tear on both the piston and liner while maintaining the necessary sealing function. This intermediary solution enhances component durability with minimal added complexity.
Data Source
AI summary
A rotary steerable tool for steering a drill string may include a tool collar extending along a longitudinal axis of the tool, a pad pusher, a pad retention housing, and a piston liner. The pad pusher may be rotatable about a pivot axis thereof between retracted and extended positions relative to the tool collar, for steering the drill string. The piston liner may be coupled to the pad retention housing and have a piston channel that defines a curved profile. The piston liner may provide sealing contact against a perimeter of the piston upon pivoting of the pad pusher through the piston channel along the curved profile, relative to the piston liner.