Impeller Blade Corner Radii for Faster Machining and Performance
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Solution Overview
Problem
Existing methods for manufacturing impellers result in longer processing times due to increased cutting traces on the suction surface, which affects performance.
Innovation Solution
The impeller design incorporates multiple concave surfaces with varying radii on the pressure and suction surfaces, processed using different end mills to optimize cutting efficiency and reduce processing time, with the largest concave radius being identical across both surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cutter corresponding to the cross-sectional shape of the corner on the pressure surface is used to achieve smaller radius on pressure surface than on suction surface, then the impeller performance is improved, but the number of cutting traces on the suction surface increases and processing time increases
Solution Approach 1:
The patent segments the blade corner into multiple discrete concave surfaces (first concave surfaces on pressure surface, second concave surface on suction surface) with different radii. This segmentation allows independent optimization of each surface's radius without requiring multiple cutting passes, thereby reducing processing time while maintaining performance benefits
Solution Approach 2:
The patent applies local quality by giving different concave radii to different locations: the pressure surface has multiple first concave surfaces with smaller radii optimized for performance, while the suction surface has a second concave surface with a larger radius. This local differentiation achieves performance improvement without proportionally increasing processing time across the entire blade
2Reliability
If multiple first concave surfaces with different concave radii are formed on the pressure surface, then the impeller performance is enhanced, but the device complexity and manufacturing complexity increase
Solution Approach 1:
The patent changes geometric parameters (concave radii) to optimize performance. By forming multiple first concave surfaces with different concave radii on the pressure surface and a second concave surface with a larger radius on the suction surface, the patent achieves enhanced performance through parameter optimization without requiring complex manufacturing processes
Solution Approach 2:
Instead of using a single cutter that would require multiple cutting passes and create many traces, the patent inverts the approach by designing the blade corner with pre-defined multiple concave surfaces of different radii. This inversion reduces the number of cutting operations needed while achieving the desired performance characteristics
Data Source
AI summary
An impeller including a hub surface and a plurality of blades protruding from the hub surface. Each of the plurality of blades has a pressure surface located on a leading side of the rotation direction and a suction surface located on a trailing side of the rotation direction. Each of the plurality of blades is provided with a plurality of first concave surfaces at a boundary between the pressure surface and the hub surface, and one second concave surface at a boundary between the suction surface and the hub surface. At least two different first concave surfaces having different concave radii in cross section are included in the plurality of first concave surfaces. A first concave radius that is the largest among the different concave radii is identical to a second concave radius that is a concave radius of the second concave surface in cross section.