Variable Guide Vane Profiled Fork for Angular Misalignment

Solution Overview

Problem

Conventional variable guide vane actuating systems in gas turbine engines experience increased wear and inaccuracy due to reduced contact between rotary actuators and actuating links, particularly for radial vanes with a wide angle range, leading to system inaccuracy.

Innovation Solution

A variable guide vane apparatus featuring a unison ring with circumferentially spaced drive pins and actuating arms with profiled slots to accommodate angular misalignment and maximize contact area between drive pins and forks, allowing for increased durability and accuracy throughout the range of motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the contact between rotary actuator and actuating links is reduced to accommodate greater VGV angle range, then the VGV angle range is improved, but wear at the link-actuator interface increases

Engineering Contradiction:

ImproveVGV angle rangeVSAvoidwear at link-actuator interface

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The fork surfaces are contoured with curved profiles instead of flat surfaces, creating a pin-fork interface where the fork has a curved surface that complements the cylindrical drive pin. This curvature allows the fork to accommodate angular misalignment while maintaining continuous contact with the pin throughout the VGV rotation range, thereby reducing wear.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the fork, specifically contouring the fork surfaces with specific curvature radii (R1, R2, R3) that vary along the length of the fork. This parameter optimization ensures maximum contact area between the pin and fork while accommodating the full range of VGV motion, resolving the contradiction between range of motion and wear resistance.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional flat fork surfaces are used, then manufacturing is simpler, but contact area between pin and fork is reduced leading to increased wear

Engineering Contradiction:

Improvefork surface fabricationVSAvoidcontact area and wear

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The fork surfaces are contoured with curved profiles instead of flat surfaces, creating a pin-fork interface where the fork has a curved surface that complements the cylindrical drive pin. This curvature allows the fork to accommodate angular misalignment while maintaining continuous contact with the pin throughout the VGV rotation range, thereby reducing wear.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the fork, specifically contouring the fork surfaces with specific curvature radii (R1, R2, R3) that vary along the length of the fork. This parameter optimization ensures maximum contact area between the pin and fork while accommodating the full range of VGV motion, resolving the contradiction between range of motion and wear resistance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11092032B2Variable vane actuating system

Publication Date: 2021.08.17 PRATT & WHITNEY CANADA CORP

AI summary

A variable guide vane (VGV) apparatus has a variable guide vane (VGV) rotatable about a vane rotation axis. An actuating arm is mounted to the VGV. The actuating arm has a fork defining a slot for receiving a drive pin. The slot is profiled to accommodate angular misalignment between the pin and the fork throughout a range of motion of the associated pin along the slot.