Load-Bearing Universal Joint With Self-Energizing Seals
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Solution Overview
Problem
Rotary steerable drilling tools face challenges with low mean time between failures, significant space usage, and increased bit-to-bend distance, which limits the range of angle and azimuth changes in directional drilling operations.
Innovation Solution
A load-bearing universal joint with self-energizing seals is introduced, featuring a convex surface on the bit shaft, a cup housing, and a spacer ring to carry axial, radial, and torsional loads, along with self-energizing seals to maintain reliability and reduce component size, allowing for a shorter bit-to-bend distance and increased angle and azimuth capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing components are used to seal the universal joint, then sealing capability is achieved, but mean time between failures is low and space consumption is high
Solution Approach 1:
The patent combines sealing and load-bearing functions into a single integrated component (the universal joint assembly with convex and concave surfaces). This merging eliminates the need for separate sealing components and bearing components, reducing overall component size while maintaining both sealing capability and load-bearing capacity, thereby improving reliability without increasing device complexity
Solution Approach 2:
The universal joint assembly is designed to perform multiple functions simultaneously: sealing the joint from contamination, carrying axial loads, carrying radial loads, and transferring torque. This multi-functionality reduces the number of separate components needed, decreasing space consumption while maintaining high reliability through integrated design
2Strength
If conventional load-bearing components are used to carry axial and radial loads, then load-bearing capability is achieved, but bit-to-bend distance increases
Solution Approach 1:
The patent merges load-bearing surfaces directly into the universal joint structure. The convex surface on the bit shaft and corresponding concave surface on the collar create integrated load-bearing contact areas that carry axial and radial loads without requiring separate bearing components, thereby reducing the bit-to-bend distance while maintaining full load-bearing capability
3Power
If conventional universal joint design is used to transfer torque, then torque transfer is achieved, but angle and azimuth range is limited
Solution Approach 1:
The patent employs a dynamic universal joint design where the bit shaft can rotate freely relative to the collar while maintaining torque transfer through the convex-concave surface interface. This dynamic configuration allows the angulating mechanism to vary the angle and azimuth within an enhanced range while continuously transferring torque from the collar to the bit shaft, improving adaptability without sacrificing power transmission
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 enhances the reliability and performance of the rotary steerable drilling tool by reducing stress on bearing surfaces, increasing the useful life, and enabling a higher possible angle and azimuth between the bit shaft and collar, while maintaining effective sealing and load-bearing capabilities.
Implementation Method 1
The first seal is adapted to seat against a first shoulder formed into the lock-nut in response to a first pressure differential. The second seal is adapted to seat against a second shoulder formed into the collar in response to a second pressure differential.
Data Source
AI summary
A rotary steerable drilling tool and a method according to which a universal joint is sealed. In one embodiment, the method includes providing the collar, the shaft, the universal joint, and first and second shoulders between which the universal joint is positioned; providing first and second self-energizing seals between the collar and the shaft on opposite sides of the universal joint; rotating the collar and the shaft; seating the first self-energizing seal against the first shoulder; and seating a second self-energizing seal against the second shoulder. In one embodiment, the universal joint includes a convex surface formed on the shaft; a first concave surface extending circumferentially about the shaft and adapted to mate with the convex surface to carry a first axial load; and a spacer ring defining a second concave surface adapted to mate with the convex surface to carry a second axial load.