Smooth-Profile Bearing Element for Continuous Hydrodynamic Flow
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Solution Overview
Problem
Conventional bearing systems for turbochargers face issues with fluid flow discontinuities and time-intensive manufacturing processes, and are not optimized for mono-directional shaft rotation, which limits shaft rotation speeds and increases noise and vibrations.
Innovation Solution
The bearing system features an inner surface with a smooth profile comprising taper, constant-radius, and transition portions, with varying radial dimensions and angular distances, creating a continuous surface that supports a cylindrical shaft and generates hydrodynamic pressure for higher speeds and reduced noise and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bearing elements are machined by cutting several arcs of constant radius into an inner surface, then the bearing can support shaft rotation, but discontinuities occur at the intersection of arcs which cause interruptions in fluid flow and increase manufacturing time
Solution Approach 1:
The inner surface is divided into multiple sections, each containing a complete wave profile with taper, constant-radius, and transition portions. This segmentation allows each section to function independently while maintaining overall fluid flow continuity, eliminating the need for complex multi-arc intersections.
Solution Approach 2:
The invention replaces the conventional constant-radius arcs with a curved profile consisting of taper portions and transition portions that smoothly connect. This curvature design eliminates sharp intersections and discontinuities, ensuring continuous fluid flow while simplifying the manufacturing process.
2Adaptability or versatility
If tri-lobe bearing elements are designed for bi-directional shaft rotation, then the bearing can accommodate both rotation directions, but the design is not optimized for mono-directional rotation which limits shaft rotation speeds
Solution Approach 1:
The wave profile is designed with asymmetric taper portions and transition portions that are optimized for mono-directional rotation. The first angular distance is greater than the second angular distance, creating an asymmetric geometry that enhances fluid film generation in the primary rotation direction while maintaining adequate performance in reverse direction.
Solution Approach 2:
The bearing profile parameters (angular distances, radius variations) are specifically tuned for mono-directional operation. By changing these geometric parameters asymmetrically, the bearing achieves higher rotation speeds in the primary direction while still providing acceptable performance for bi-directional applications.
3Speed
If the inner surface has a smooth profile with varying radial dimensions and continuous surface transitions, then hydrodynamic pressure is generated for higher speeds and reduced noise, but the manufacturing complexity increases
Solution Approach 1:
The complex smooth profile is broken down into three distinct but simple portions: taper portions, constant-radius portions, and transition portions. Each portion has a straightforward geometric definition that simplifies manufacturing while collectively achieving the desired smooth continuous profile for hydrodynamic pressure generation.
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 innovative bearing design allows for higher rotational speeds, reduced noise, and minimized vibrations by optimizing the inner surface geometry for unidirectional fluid flow and hydrodynamic pressure generation, enhancing the performance of turbocharger systems.
Implementation Method 1
creating a continuous surface that supports a cylindrical shaft and generates hydrodynamic pressure for higher speeds and reduced noise and vibrations
Data Source
AI summary
A bearing element includes an inner surface (54) configured to receive a cylindrical shaft (18). The inner surface (54) includes a smooth profile having a plurality of sections (502). Each section (502) having a taper portion (506) between a first arc-span point (512) and a second arc-span point (514), a constant-radius portion (508) between the second arc-span point (514) and a third arc-span point (516), and a transition portion (510) between the third arc-span point (516) and a fourth arc-span point (518). An inner-surface radius dimension (520) changes from an inner-diameter major dimension to an inner-diameter minor dimension at the taper portion (506) and back at the transition portion.