Compressor Wheel Hub Contouring for Stress Reduction
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Solution Overview
Problem
Existing compressor wheels for turbochargers have durability issues due to complex and time-consuming manufacturing processes, particularly in achieving variable radiusing for blade connections, which complicates the production and increases stress in the material.
Innovation Solution
A compressor wheel design featuring a hub with both rotationally and non-rotationally symmetrical portions, where the transition between the hub and blades includes a region of modified thickness to reduce material stress, achieved through contoured machining that forms control rays, allowing for a quasi-orthogonal surface and reduced elevations from milling steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If variable radiusing is used in the transition between hub and blades, then the durability or service life of the compressor wheel is improved, but the manufacturing complexity increases and production time is extended
Solution Approach 1:
The hub is designed with different thickness regions: a first region with greater thickness in the blade connection area and a second region with smaller thickness elsewhere. This local variation in thickness provides the necessary radiused transition for durability while simplifying the overall manufacturing process by using standard milling operations rather than complex variable radiusing.
2Reliability
If variable radiusing is used in the transition between hub and blades, then the service life is improved, but the production time increases
Solution Approach 1:
Instead of applying variable radiusing throughout the entire hub-blade transition, the invention uses a localized thicker region only where needed for blade connection durability. This allows standard milling operations to complete the work in one pass without requiring additional time-consuming radiusing operations.
3Reliability
If a non-rotationally symmetrical hub with modified thickness region is used, then material stress is reduced and service life is extended, but the manufacturing precision requirements increase
Solution Approach 1:
The hub features a localized thicker region with controlled contours that can be achieved through standard milling operations. The contouring is performed in a way that generates control rays to reduce stress concentrations, and the process can be integrated into conventional manufacturing cycles without requiring excessive precision beyond standard capabilities.
4Ease of manufacture
If standard milling operations are used, then manufacturing simplicity is maintained, but stress concentrations from milling lines reduce durability
Solution Approach 1:
The thicker region of the hub is contoured with curved surfaces that generate control rays. These curved contours smooth out stress concentrations that would otherwise occur at sharp milling lines, thereby improving durability while maintaining the simplicity of standard milling operations.
Solution Approach 2:
The invention changes the geometric parameters of the hub by introducing a thicker region with specific contouring. This parameter change creates control rays that redistribute stress away from milling lines, improving durability without requiring complex manufacturing processes.
Data Source
AI summary
A compressor wheel for a compressor of a turbocharger has a hub and a multiplicity of blades on the hub. In intermediate spaces of the multiplicity of blades, a channel is in each case formed between a suction side and a pressure side. The channel guides fluid that flows in axially in relation to a rotation axis radially or radially-axially outward. The hub in relation to the rotation axis is contoured such that the hub has a rotationally symmetrical portion and a non-rotationally symmetrical portion. On the non-rotationally symmetrical portion, a transition between the hub and each of the blades is embodied with a radiused connection and facing the suction side has a region of modified thickness. A region formed by control rays is generated in at least one channel between the suction side and the pressure side on the hub. A method produces the compressor wheel.