Profiled Turbocharger Bearing Surface for Friction Reduction

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Solution Overview

Problem

Bearing systems in turbochargers face challenges in maintaining low friction and efficient operation in high-temperature, high-speed environments, particularly in managing forces and ensuring stability and rotational speed without excessive vibration or noise.

Innovation Solution

The implementation of a bearing system with a profiled inner circumferential surface that directs lubricant flow through axial and circumferential convergence, using hydrodynamic oil film interfaces and magnetic levitation for rotor support, allowing for efficient lubrication and reduced friction, while maintaining the lubricant within the interface through directed convergence and controlled oil flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional bearing surfaces are used in turbochargers, then the structure is simple and easy to manufacture, but friction is high and rotational speed is limited

Engineering Contradiction:

Improverotational speedVSAvoidfriction

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The bearing surface is modified with a specific profile geometry that creates localized hydrodynamic pressure zones. The profile includes a leading edge, a peak, and a trailing edge that work together to generate and maintain the oil film, providing different functional zones across the surface rather than a uniform structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bearing surface features a curved profile with specific radii of curvature. The profile includes a rounded leading edge and a curved peak that facilitate smooth fluid flow and pressure distribution, utilizing geometric curvature to enhance hydrodynamic lubrication effects.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If higher rotational speeds are achieved, then productivity increases, but vibration and noise increase

Engineering Contradiction:

Improverotational speedVSAvoidvibration and noise

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The bearing profile is designed to pre-establish the hydrodynamic oil film before contact occurs. The leading edge of the profile begins to draw in and pressurize the lubricant ahead of the rotating surface, creating a cushioning effect that prevents impact and reduces vibration at high speeds.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The hydrodynamic oil film acts as an intermediary between the bearing surface and the rotating shaft. This fluid layer absorbs and dampens vibrations and noise generated by high-speed rotation, preventing direct transmission of mechanical disturbances.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If hydrodynamic oil film interface is used, then friction is reduced, but lubricant leakage occurs

Engineering Contradiction:

ImprovefrictionVSAvoidlubricant leakage

Core Design Contradiction:

Loss of energyVSLoss of substance

Solution Approach 1:

The bearing profile extends in the axial dimension with a specific three-dimensional geometry. The profile includes axial length and curvature that work together to contain the lubricant within the bearing interface, adding an axial containment dimension to the otherwise radial hydrodynamic action.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Temperature

If bearing operates in high temperature environment, then turbocharger performance improves, but lubricant stability deteriorates

Engineering Contradiction:

Improveoperating temperatureVSAvoidlubricant stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The bearing profile geometry enables the system to generate its own hydrodynamic pressure and maintain the oil film without external assistance. The profile automatically adjusts the lubricant flow and pressure distribution based on operating conditions, providing self-regulating lubrication that maintains film stability across a range of temperatures.

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

This solution enhances the bearing system's ability to manage high-speed and high-temperature conditions by reducing friction, noise, and vibration, enabling higher rotational speeds and stability, while maintaining efficient lubrication and preventing lubricant leakage.

Implementation Method 1

using hydrodynamic oil film interfaces and magnetic levitation for rotor support

Methodology Applied

Scientific EffectHydrodynamic lubrication: Lubrication

Implementation Method 2

magnetic levitation for rotor support

Methodology Applied

Scientific EffectMagnetic levitation: Maglev

Data Source

PatentUS20170284458A1Turbocharger bearing fluid film surface and method

Publication Date: 2017.10.05 BORGWARNER INC

AI summary

A bearing system and method may include a bearing element that may have a first surface. A mating element may have a second surface that may face the first surface. A fluid film interface may be defined between the first and the second surfaces. The mating element may rotate about an axis and relative to the bearing element. An axial direction may be defined parallel to the axis. A radial direction may be defined perpendicular to the axis. The first surface may have a profile that may vary in the axial direction and that may varies in the radial direction. The profile may direct a fluid present in the fluid film interface in a direction or directions having circumferential and/or axial components.