Variable Turbomachine Vane Radial Clamping Mechanism
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Solution Overview
Problem
In turbomachines with variable vanes, the diameters of shoulders for vane stems are reduced due to the minimum thread diameter required for tightening nuts, especially in cases with slender vane stems, leading to reduced engagement surface area and increased load, which complicates the mounting process.
Innovation Solution
A vane assembly with a vane stem featuring a first engagement surface that is not inclined more than 15° relative to the longitudinal axis, allowing for self-centering and improved force transmission, and a clamping mechanism that compresses transversely to the longitudinal axis, enabling a larger engagement surface and reducing the load on the vane stem, while also serving as a supporting surface for the actuating means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nuts are used to clamp actuating means against shoulders of vane stems, then the actuating means can be securely fastened, but the diameters of shoulders are reduced due to the minimum thread diameter required for tightening
Solution Approach 1:
The patent transitions from axial clamping (along the longitudinal axis of the vane stem) to radial clamping (perpendicular to the longitudinal axis). The clamping means now acts radially inward to clamp the actuating means against the lateral engagement surface, eliminating the need for axial shoulders and allowing the full diameter of the vane stem to be utilized for engagement.
Solution Approach 2:
Instead of clamping the actuating means from the axial direction against a shoulder, the patent inverts the clamping direction to act radially from the lateral surface of the vane stem. This inversion allows the engagement surface to be the lateral surface itself rather than a reduced-diameter axial shoulder.
2Ease of manufacture
If axial clamping is used to secure the actuating means, then the mounting process is simplified, but the load on the vane stem increases and the design becomes less compact
Solution Approach 1:
The clamping force is applied radially rather than axially, distributing the load more effectively across the vane stem structure. The lateral engagement surface is designed to withstand radial clamping forces, reducing the concentrated axial load that would require a larger shoulder diameter.
3Stability of the object's composition
If the engagement surface is inclined more than 15° relative to the longitudinal axis, then self-centering is achieved, but force transmission is reduced
Solution Approach 1:
The engagement surface is designed with a specific inclination angle parameter (≤15° relative to the longitudinal axis, or alternatively ≥75° relative to the radial direction). This parameter optimization balances the self-centering effect (which requires some inclination) with force transmission efficiency (which deteriorates with high inclination). The curved convex shape further optimizes this balance by providing progressive contact.
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 configuration enhances the mounting process, stability, and reliability, particularly for slender vane stems, by providing a larger engagement surface and allowing for compact design, while ensuring secure clamping without axial clamping, thus improving the overall mounting efficiency.
Implementation Method 1
the actuating means is clamped, in particular pressed, against the first engagement surface through or by partially or fully elastic compression of the clamping means in a direction transverse to the longitudinal axis of the vane
Data Source
AI summary
A vane assembly for a turbomachine includes a variable vane (10-15), the vane having at least one first, in particular plane or curved, engagement surface (11; 11′) for clamping, in particular without play, an actuator (20) of the vane assembly for adjustment of the vane, this first engagement surface not being inclined toward a longitudinal axis (L) of the vane or being inclined toward it by no more than 15°, and/or the vane assembly including a clamp (30; 31) for clamping the actuator against the first engagement surface by at least partially elastically compressing the clamp transversely to the longitudinal axis of the vane and/or by advancing the clamp in a clamp direction (S) that forms an angle of at least 45° with the longitudinal axis of the vane.