Lock Ring Wedging for Wear Sleeve Securing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotary well tools face issues with relative movement between wear sleeves and shafts due to friction from rotary seals, leading to seal failure and reduced seal life, as well as fretting issues from axial movement, which compromises the structural integrity and reliability of the sealing interfaces.
Innovation Solution
A protective sleeve is mounted co-axially on the shaft with a socket formation and a lock ring that is wedged between the sleeve and the shaft using tapered surfaces and screw threads, preventing relative movement and enhancing the securement of the sleeve to the shaft through axial penetration and tightening torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a wear sleeve is mounted on the shaft to protect it from wear at the rotary seal interface, then the shaft is protected from wear, but relative movement between the sleeve and shaft occurs due to friction from the rotary seal
Solution Approach 1:
The wear sleeve is designed as a separate, removable component that can be independently replaced from the shaft. This segmentation allows the sleeve to be replaced without replacing the shaft, while the securing mechanism ensures no relative movement occurs between the two components during operation.
Solution Approach 2:
The securing mechanism is designed to prevent relative movement before it can occur. The lock ring with tapered surfaces and screw threads is pre-configured to create friction and mechanical interlocking that stops any potential relative motion between the wear sleeve and shaft, thereby protecting the rotary seal integrity.
2Reliability
If the wear sleeve is secured to the shaft to prevent relative movement, then seal integrity is maintained, but the complexity of the assembly increases due to additional securing components
Solution Approach 1:
The securing mechanism combines multiple functions into integrated components. The lock ring simultaneously provides axial positioning, radial retention, and rotational locking. The tapered surfaces and screw threads are integrated into the lock ring and wear sleeve as unified features rather than separate elements, reducing the total number of discrete parts.
Solution Approach 2:
The lock ring acts as an intermediary component between the wear sleeve and shaft. It transfers and distributes the securing forces from the wear sleeve to the shaft through its tapered surfaces and screw threads, providing a reliable connection without requiring direct bonding or complex multi-component assemblies.
3Reliability
If a lock ring is used to secure the wear sleeve to the shaft, then relative movement is prevented, but axial movement can still cause fretting issues at the seal interface
Solution Approach 1:
The securing mechanism applies different types of constraints at different locations and directions. The lock ring provides strong radial and rotational constraints through its tapered surfaces, while the screw threads provide axial constraint. This localized differentiation of constraint types ensures complete prevention of relative movement in all directions, eliminating fretting damage risk.
Solution Approach 2:
The securing mechanism utilizes composite structural features combining different material properties. The lock ring incorporates hardened surfaces for wear resistance at the tapered interfaces, while the screw threads provide threaded engagement for axial locking. This composite approach ensures both the wear sleeve and shaft are securely constrained against all types of relative movement.
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
This solution effectively prevents relative rotational, radial, and axial movement between the wear sleeve and shaft, improving the reliability and longevity of rotary seals by eliminating stress concentrations and promoting secure anchoring, thus enhancing tool run times and structural integrity in downhole environments.
Implementation Method 1
a wedging mechanism configured to cause wedging of the lock ring between the protective sleeve and the shaft in response to axial penetration of the lock ring into the annular socket
Implementation Method 2
a screw-thread provided on a radial periphery of the ring body, the screw-thread being configured for screwing engagement with a complementary screw-thread to cause axial advance of the lock ring into the socket cavity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and apparatus are provided for securing a protective sleeve or wear sleeve to a rotary component which is rotatable relative to a rotary seal, such that the wear sleeve is in relatively rotating sealing engagement with the rotary seal. The wear sleeve is secured to the shaft by wedging a lock ring between the wear sleeve and the shaft. Wedging action of the lock ring can be effected by wedging formations, such as tapered surfaces, configured for causing wedging of the lock ring in response to operator-induced axial movement of the lock ring relative to the shaft and/or the wear sleeve. Wedging of the lock ring can be effected by cooperating screw threads on the lock ring and the wear sleeve, so that an operator can tighten the sleeve on the shaft by application of torque thereto.