Variable Guide Vane Bearing Wear Reduction
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Solution Overview
Problem
In gas turbine engine compressors, variable-pitch stator blades experience wear and excessive inclination due to aerodynamic forces, leading to damage from the moment applied to the bearings, and increased operating forces.
Innovation Solution
The distance between the aerodynamic force application point and the lower pivot bearing is reduced, minimizing the moment applied to the blade and distributing loads through a bottom bearing, which includes a rib and groove configuration for integrated bearing support, reducing wear and maintaining acceptable friction for control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between the aerodynamic force application point and the lower pivot bearing is reduced, then the moment applied to the blade is reduced and wear is reduced, but the structural complexity increases due to the integrated bearing configuration
Solution Approach 1:
The patent combines the bearing function directly into the platform structure through an integrated bearing configuration. The bearing is formed by the cooperation of a rib on the socket and a groove in the platform, merging two previously separate components (bearing and platform) into a unified structure. This eliminates the need for separate bearing housings and reduces the number of parts while maintaining the load-bearing and guidance functions.
Solution Approach 2:
The patent transitions from a separate axial bearing component to an integrated planar bearing configuration embedded in the platform. The bearing functionality is achieved through the rib-groove interface on the platform face, effectively moving the bearing function into the platform's dimensional structure rather than requiring a separate axial component.
2Reliability
If the aerodynamic forces on variable-pitch stator blades are reduced, then wear and blade inclination are prevented, but the control authority over blade pitch is reduced
Solution Approach 1:
The patent introduces a counterbalancing moment through the integrated bearing configuration that opposes the aerodynamic moment. By reducing the distance between the aerodynamic force application point and the lower pivot bearing, the aerodynamic moment is reduced, and the bearing configuration provides a counterbalancing reaction that maintains control authority while preventing excessive wear and blade inclination.
3Ease of operation
If the operating forces of variable-pitch stator blades are increased, then better control over blade pitch is achieved, but wear of the guide device bushings increases
Solution Approach 1:
The patent replaces the traditional sliding bushing mechanism with a rolling element bearing configuration. The integrated bearing with rib and groove interface eliminates sliding contact between the pivot and socket, substituting it with a rolling element bearing system that significantly reduces friction and wear while maintaining the necessary control forces for blade pitch 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 results in a 17% and 30% reduction in reaction forces, lowering wear and maintaining operational control, with reduced moment and distributed loads, thereby preventing blade inclination and extending component lifespan.
Implementation Method 1
The two parts, rib and groove, form an integrated bearing 23b1-26b1 which takes up the aerodynamic forces applied to the blade and transmits them to the casing 3
Implementation Method 2
the bearing is formed by the cooperation of a rib 26b1 and a groove 23b1. The circular rib is provided on the face of the socket facing the platform 23
Data Source
Figure 1~3
AI summary
The present invention relates to a variable-pitch stator blade guide device for an axial turbomachine, the blade comprising a blade (22), a platform (23), and a pivot (24) mounted in the turbomachine housing. The device is characterized in that it includes a bearing integrated into the platform. In particular, the device includes a sleeve (26) between the platform and the housing, and the integrated bearing is formed between the sleeve and the platform. Specifically, a circular rib (26b1) is formed on a portion (26b) of the disc-shaped sleeve (26) cooperating with a complementary groove (23b1) formed on the platform, so as to form a plain bearing between them.