Self-Centering Turbocharger Vane Pivot for Thermal Distortion

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Solution Overview

Problem

Variable turbine geometry (VTG) turbochargers face challenges in maintaining geometric parallelism and efficient operation due to thermal distortion, leading to reduced efficiency and potential failure of securing mechanisms, especially at high temperatures.

Innovation Solution

A vane pack assembly with single-axle, self-centering adjustable guide vanes featuring a hemi-spherical or conical pivot feature that allows for misalignment tolerance, enabling continued operation despite thermal expansion and deformation, and an actuation mechanism for controlling exhaust gas flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional securing mechanisms are used to maintain vane alignment, then geometric parallelism is maintained at low temperatures, but the mechanisms fail or lose effectiveness at high temperatures due to thermal distortion

Engineering Contradiction:

Improvesecuring mechanism durabilityVSAvoidoperating temperature range

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The pivot feature incorporates a spherical element (ball) that fits within a spherical recess, creating a ball-in-socket joint. This curved geometry allows the vane to pivot and self-center, accommodating thermal distortion while maintaining reliable connection between the vane and vane ring assembly across a wide temperature range.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The pivot feature allows the vane to change its angular position dynamically in response to thermal expansion and distortion. Instead of rigidly maintaining geometric parallelism, the system permits parameter changes in vane orientation to accommodate thermal effects, thereby maintaining reliability at high temperatures.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If rigid vane mounting is used to maintain precise alignment, then geometric parallelism is maintained, but thermal distortion causes binding and failure of the mounting mechanisms

Engineering Contradiction:

Improvevane alignment precisionVSAvoidthermal distortion

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The vane mounting transitions from a rigid, fixed-position connection to a dynamic, movable joint. The ball-in-socket pivot feature enables the vane to move and self-center dynamically in response to thermal distortion, preventing binding while maintaining functional alignment through controlled motion rather than rigid constraint.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If dual-axle pivot mechanisms are used to accommodate misalignment, then tolerance for thermal distortion increases, but device complexity and potential failure points increase

Engineering Contradiction:

Improvemisalignment toleranceVSAvoidpivot mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention extracts only the essential degree of freedom needed to accommodate thermal distortion - a single axial pivot movement - rather than implementing complex multi-axle mechanisms. This simplified single-axle pivot with ball-in-socket geometry provides sufficient misalignment tolerance while reducing mechanical complexity and potential failure points.

Inventive Principle:

Principle #2Taking out (Extraction)

4Stability of the object's composition

If multiple fasteners are used to secure vane rings to turbine housing, then geometric parallelism is maintained, but stress concentration increases at high temperatures

Engineering Contradiction:

Improvevane ring positioning stabilityVSAvoidfastener stress

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The ball-in-socket pivot feature enables the vane to self-center and maintain proper alignment automatically through its geometry, eliminating the need for multiple fasteners to enforce geometric parallelism. This self-aligning mechanism reduces stress concentration on fasteners while maintaining positioning stability through the inherent geometry of the spherical joint.

Inventive Principle:

Principle #25Self-service

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

The solution enhances durability and efficiency by maintaining vane alignment and reducing stress on securing mechanisms, allowing the turbocharger to operate effectively across a wide temperature range and extending its lifespan.

Implementation Method 1

enabling continued operation despite thermal expansion and deformation

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10240480B2Variable turbine geometry vane with single-axle, self-centering pivot feature

Publication Date: 2019.03.26 BORGWARNER INC

AI summary

A vane pack assembly (25) for a variable geometry turbocharger (10) including a an upper vane ring (28) and a lower vane ring (30) and a plurality of single-axle, self-centering adjustable guide vanes (26) disposed in a turbine housing (20). The plurality of guide vanes (26) include a post (50) having a vane (52) formed integrally therewith. Each post (50) includes a convex self-centering pivot feature (56a, 56b) at one end adapted to seat in a complementary shaped concave self-centering pivot recess (48) of the lower vane ring. The vanes (52) are positioned between the upper and lower vane rings (28, 30) and pivot to control exhaust flow to a turbine wheel. The self-centering pivot features compensate for movement or deformation of the turbine housing (20) and vane rings (28, 30) due to the effects of differential thermal expansion.