Axial-flow Fan Hub Reinforcement with Segmented Ribs

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Solution Overview

Problem

Axial-flow fans used in automobiles for engine cooling often have a weak fan hub when equipped with swept fan blades, leading to increased deflection and stress during operation.

Innovation Solution

The axial-flow fan design incorporates a hub with an open and substantially closed end, featuring a plurality of ribs strategically aligned to reduce stress and deflection, with each rib positioned relative to the blades' edges to provide targeted reinforcement, ensuring the hub's stability and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If swept fan blades are used to improve cooling efficiency, then the fan's cooling performance is enhanced, but the hub becomes weaker and experiences increased deflection and stress

Engineering Contradiction:
Improvecooling efficiencyVSAvoidhub strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The hub is segmented into multiple reinforcing ribs that are strategically positioned to provide localized support. The ribs divide the hub structure into multiple load-bearing segments, allowing the hub to maintain strength while accommodating the swept blade design that improves cooling efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Reinforcing ribs are added at specific locations where stress and deflection are most critical. The ribs are positioned based on stress analysis to provide local reinforcement exactly where needed, rather than uniformly strengthening the entire hub. This allows the hub to maintain adequate strength while minimizing weight and material usage.

Inventive Principle:
Principle #3Local quality

2Strength

If the hub structure is strengthened to reduce deflection and stress, then the hub's structural integrity is improved, but the fan's complexity increases

Engineering Contradiction:
Improvehub structural integrityVSAvoidhub structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The hub structure is divided into multiple reinforcing ribs that are integrated into the overall hub design. These ribs are positioned to provide maximum structural benefit with minimal added complexity. The segmented rib structure allows for systematic reinforcement without requiring complete redesign of the entire hub assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcing ribs are merged with the hub as an integral structure rather than separate components. The ribs are formed as part of the hub molding process, combining the reinforcement function with the existing hub geometry. This integration reduces assembly steps and minimizes the increase in device complexity while achieving the desired structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2569544B1Axial-flow fan
Publication Date: 2015.07.08 ROBERT BOSCH GMBH
  • EP2569544B1 patent drawingFigure 1~2
  • EP2569544B1 patent drawingFigure 3~4
  • EP2569544B1 patent drawingFigure 5~6

AI summary

A fan includes a hub and blades. A first edge of each blade is proximate an open end of the hub. A first rib is coupled to the hub and substantially aligned with a first plane intersecting the central axis and an intersection of the first edge of the first blade with the hub. The first plane is angularly spaced from a reference plane intersecting the central axis and an intersection of the first edge of the second blade with the hub. An angular spacing between the first plane and the reference plane defines one sector. A second rib is aligned with a second plane angularly positioned between the first plane and the reference plane at a location less than or equal to about (1/nR - 0.05) sectors from the first plane, in which nR equals the number of ribs divided by the number of blades.