Variable Vane Drive Roller Support for Thermal Expansion
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Solution Overview
Problem
Existing axial-flow fluid machines face challenges in maintaining smooth rotation and setting variable vanes to a target angle due to thermal expansion differences between the vane holding ring and the movable ring, leading to potential overload or misalignment.
Innovation Solution
The axial-flow fluid machine incorporates a variable vane drive device with a ring support unit that includes first, second, and third rollers, allowing relative movement in the radial direction while restricting axial movement, ensuring stable and smooth rotation and precise angle setting of variable vanes through a carefully designed roller configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable ring is supported only at the lower side by rollers, then the movable ring can move upward freely to accommodate thermal expansion, but the variable vane cannot be set to the target angle precisely
Solution Approach 1:
The support function is segmented into three distinct roller types: first rollers for radial support and rotation, second rollers for axial positioning, and third rollers for thermal expansion accommodation. This segmentation allows each component to perform its specific function without interfering with others, resolving the contradiction between free thermal expansion and precise angle setting.
Solution Approach 2:
The third rollers act as intermediaries between the movable ring and the fixed structure, allowing controlled radial movement to accommodate thermal expansion while the second rollers maintain axial positioning. This intermediary mechanism enables both thermal expansion freedom and angle precision simultaneously.
2Manufacturing precision
If the movable ring is constrained rigidly to prevent thermal expansion, then the angle setting can be precise, but the rotation becomes overloaded and not smooth
Solution Approach 1:
Different regions of the movable ring are provided with different support characteristics: the first rollers provide rigid radial support for rotation, while the third rollers provide compliant support for thermal expansion. This local differentiation of support quality allows precise angle setting in the axial direction while accommodating thermal expansion in the radial direction.
3Manufacturing precision
If multiple rollers are added to support the movable ring in both radial and axial directions, then both smooth rotation and precise angle setting are achieved, but the device complexity increases
Solution Approach 1:
Each roller type serves multiple functions: the first rollers provide radial support and enable rotation, the second rollers provide axial positioning and maintain contact pressure, and the third rollers accommodate thermal expansion while maintaining structural integrity. This multi-functionality reduces the need for additional specialized components, managing complexity while achieving the desired precision and smooth operation.
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 ensures smooth rotation of the movable ring and precise setting of variable vanes to a target angle, even with thermal expansion differences, preventing overload and maintaining uniform distance for accurate vane positioning.
Implementation Method 1
a plurality of first rollers (41) which makes a rolling contact with the movable ring (31)
Implementation Method 2
one or more second rollers (51) which make rolling contact with the movable ring (31)
Implementation Method 3
The one second roller is pressed downward by a spring, and presses the movable ring downward
Implementation Method 4
one or more third rollers (61) which are disposed in such a way that a space is secured between the third rollers (61) and the movable ring (31) in the radial direction (Dri), allow relative movement of the movable ring (31) in the radial direction (Dri)
Implementation Method 5
a temperature difference is generated between an inside and an outside of the vane support ring during a startup process and a shutdown process of the axial-flow compressor, and a thermal expansion difference is generated between the vane support ring and the movable ring disposed at the outer circumferential side of the vane support ring
Data Source
AI summary
In a variable vane drive device of an axial-flow fluid machine, a ring support unit supporting a movable ring includes: a first roller; a first support part supporting the first rollers so as to be relatively immovable with respect to a vane holding ring in a radial direction and in an axial direction; a second roller; a second support part supporting the second roller so as to be relatively movable with respect to the vane holding ring in the radial direction and pressing the second roller in the radial direction; a third roller allowing relative movement of the movable ring in the radial direction and restricting relative movement of the movable ring in the axial direction; and a third support part supporting the third roller so as to be relatively immovable with respect to the vane holding ring in the axial direction and in the radial direction.