Turbo-Engine Vane Control Ring Centring Locking
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Solution Overview
Problem
Existing devices for adjusting the centring of control rings in turbo-engines fail to maintain precise immobilization of pad adjustment threaded rods during operation, leading to wear and loss of adjustment due to vibrations, affecting vane pitch precision.
Innovation Solution
A device with radially tapped holes and tangentially oriented slots, combined with pinching mechanisms and bolt-connection systems, allows for reliable locking of pad holders in position, ensuring precise centring and stability of the control ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If threaded rods are used to adjust pad radial position, then control ring concentricity can be adjusted, but vibration causes wear of threads leading to loss of adjustment and control ring vibration
Solution Approach 1:
The slot acts as an intermediary element between the threaded rod and the control ring. The keyed connection between the slot and the rod's head prevents relative rotation, while the slot itself serves as the element that gets pinched to provide locking. This intermediary structure resolves the contradiction by allowing adjustment during assembly while preventing vibration-induced loosening during operation.
Solution Approach 2:
The invention replaces the traditional fully-threaded rod connection with a hybrid system combining a partially-threaded rod, a slot, and a pinching mechanism. This substitution transforms the connection from purely threaded (prone to vibration loosening) to a combination of threaded positioning plus mechanical pinching locking, eliminating the reliability issue while maintaining adjustability.
2Device complexity
If a simple threaded rod adjustment system is used, then device complexity is reduced, but reliable locking during all operating phases cannot be achieved
Solution Approach 1:
The invention merges three functions into a compact integrated system: the threaded rod provides radial adjustment, the slot provides rotational positioning and transmission, and the pinching mechanism provides locking. This merging achieves reliable locking without requiring separate complex adjustment and locking mechanisms, thus maintaining simplicity while improving reliability.
3Reliability
If multiple adjustment components are added to prevent vibration wear, then reliability improves, but device complexity increases
Solution Approach 1:
The invention applies local quality by making the locking feature localized to the slot-rod interface rather than requiring complex global structural changes. The slot is simply key-shaped with a narrowed section that creates a pinching point, providing localized vibration resistance without affecting the overall simplicity of the control ring structure.
Data Source
AI summary
The invention relates to a device for adjusting the centring of a turbo-engine pivoting vane control ring, comprising a control ring (26) centred on a longitudinal axis (X-X) of the turbo-engine and provided with a plurality of tapped holes (36) running in a radial direction and a plurality of pad holders (32), each comprising a threaded rod (34) screwed into one of the ring's tapped holes (36), each pad holder (32) holding, at an inner end, a pad (30) intended to come into contact with a cylindrical shell (28), coaxial with the ring. The control ring (26) comprises, in addition, a plurality of slots (38) running in a tangential direction, each slot (38) communicating with one of the ring's tapped holes (36) The device comprises means (40, 42a, 42b) of pinching, in a longitudinal direction, each of the slots (38) in such a way as to lock the pad holders (32) in position.