Nose Cone Attachment via Lock Ring in Gas Turbine Fan Section
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Solution Overview
Problem
Existing nose cone attachment methods in gas turbine engine fan sections are inefficient, lacking a direct and secure mechanism to prevent axial and rotational movement, which can lead to instability and reduced performance.
Innovation Solution
A lock ring system is used to secure the nose cone directly to the fan section, featuring circumferentially spaced slots and pins for interference fit, along with fastening elements to prevent rotational movement, ensuring a stable attachment of the nose cone to the fan hub.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional retaining ring or pilot ring is used to locate the nose cone, then the nose cone can be positioned, but the attachment is not secure and stable, allowing axial and rotational movement
Solution Approach 1:
The patent combines the nose cone attachment function with the existing lock ring assembly that secures fan blades to the hub. The nose cone is integrated to the lock ring through direct attachment, eliminating the need for separate retaining rings or pilot rings. This merging of functions provides secure attachment while simplifying the overall device structure.
Solution Approach 2:
The lock ring assembly serves multiple functions: it secures the fan blades to the hub and simultaneously provides a secure mounting structure for the nose cone. The circumferentially spaced slots and pins in the lock ring create an interference fit that prevents both axial and rotational movement of the nose cone, making the same structural elements serve multiple purposes.
2Loss of energy
If the nose cone is not securely attached to prevent rotational movement, then the attachment mechanism is simple, but aerodynamic performance is reduced due to instability
Solution Approach 1:
The patent integrates rotational prevention features directly into the lock ring and nose cone assembly. The circumferentially spaced slots in the lock ring align with corresponding pins, creating an interference fit that prevents rotation. This combines the rotational constraint function with the existing attachment structure, preventing airflow losses without adding separate complex fastening mechanisms.
3Reliability
If discrete locating elements with interference fit are used in slots, then rotational movement is prevented, but the device complexity increases
Solution Approach 1:
The circumferentially spaced slots and pins are already part of the lock ring assembly's standard structure for securing fan blades. By utilizing these existing structural elements for nose cone rotational prevention, the patent avoids adding separate locating elements. The same slots and pins that provide blade retention also provide rotational stability for the nose cone, eliminating redundancy.
Data Source
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AI summary
A fan section for a gas turbine engine includes a fan hub having blade slots for receiving a root of a fan blade. A lock ring is configured to move rotatably from an unlocked position to a locked position for securing the blade root in the blade slot. A nose cone is secured to the lock ring, and thereby secured to the fan section.