Lock Ring Nut Assembly for Landing Gear Anti-Rotation
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Solution Overview
Problem
Landing gear joints in aircraft are susceptible to nut rotation relative to the pin under axial loads, leading to decoupling issues, which existing technologies fail to adequately address.
Innovation Solution
A nut locking assembly comprising a pin with radially inward grooves, a nut with radially outward grooves, and a lock ring with outer and inner protrusions, along with a retaining ring, which secures the nut to the pin, reducing rotation and enhancing torque resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional nut and pin assembly is used in landing gear joints, then the structure is simple, but the nut is susceptible to rotation and decoupling under axial loads
Solution Approach 1:
The locking assembly is segmented into distinct functional components: the pin with radially inward grooves, the nut with radially outward grooves, and the lock ring with protrusions. Each component has a specific function, and together they create a reliable locking mechanism that prevents nut rotation while maintaining structural integrity.
Solution Approach 2:
The lock ring is nested between the nut and the pin, with its protrusions fitting into the grooves of both components. This nested configuration creates a compact, integrated locking system that secures the nut to the pin without requiring additional external locking mechanisms.
2Strength
If longer pin and nut lengths are used to increase torque resistance, then torque resistance improves, but the overall assembly size and weight increase
Solution Approach 1:
The grooves and protrusions are designed with curved, radially oriented surfaces that conform to the cylindrical geometry of the pin and nut. This curved configuration optimizes the distribution of contact stresses and enhances torque resistance by creating favorable mechanical leverage throughout the engagement interface.
Solution Approach 2:
The locking mechanism transitions from relying solely on axial engagement to utilizing radial dimensionality through the grooves and protrusions. The radially oriented features create mechanical interlocking that resists torque in the tangential direction, effectively adding a dimensional component to the locking capability without increasing axial length.
3Reliability
If the lock ring has uniform protrusion thickness, then manufacturing is simpler, but it cannot accommodate varying gap requirements for optimal locking
Solution Approach 1:
The lock ring features non-uniform protrusion thickness, with each protrusion tailored to match the specific gap requirements at its location. This local variation in geometry optimizes the engagement between the lock ring and the grooves, ensuring reliable locking while accommodating variations in assembly tolerances and load conditions.
Data Source
AI summary
A nut locking assembly may comprise a pin, a nut, and a lock ring. The pin may include an outer diameter threaded surface and a plurality of radially inward extending grooves formed between the outer diameter threaded surface and an end of the pin. The nut may include an inner diameter threaded surface and a plurality of radially outward extending grooves formed between the inner diameter threaded surface and an axial end of the nut. The lock ring may include a plurality of outer diameter protrusions and a plurality of inner diameter protrusions.