Engine Cooling Fan Hub Alignment Reduces Distortion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing engine cooling fan assemblies face issues with fan movement and distortion due to uneven pressure distribution, particularly at high temperatures, caused by the design of the clip and drive member contact zones.

Innovation Solution

The fan assembly features a fan hub with discrete drive member contact zones on the inner face and clip contact zones on the outer face, aligned to reduce bending moments and distortion, where the clip applies pressure only to the pads of the drive member, minimizing pressure between them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the clip applies pressure to the fan hub to secure the fan to the drive shaft, then the fan is firmly attached and inhibited from movement, but uneven pressure distribution causes fan distortion particularly at high temperatures

Engineering Contradiction:
Improvefan attachment stabilityVSAvoidfan hub distortion
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The clip is designed with specific contact zone locations on the fan hub that correspond to reinforcement ribs or strengthened areas. These localized contact zones concentrate the clamping force at discrete points rather than distributing it uniformly, allowing the fan hub to be secured firmly while preventing distortion in critical areas through strategic placement of pressure points.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the drive member and clip contact zones are misaligned, then the fan can be easily assembled, but bending moments cause fan distortion under thermal load

Engineering Contradiction:
Improveassembly simplicityVSAvoidfan hub bending distortion
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The drive member and clip are designed with asymmetric contact zone patterns that are deliberately misaligned in a specific configuration. This asymmetric arrangement creates a predetermined stress distribution pattern that compensates for thermal expansion effects, reducing bending moments and distortion when the fan operates under high temperature conditions.

Inventive Principle:
Principle #4Asymmetry

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 alignment of contact zones reduces bending moments and distortion of the fan shape, especially under high temperatures, by concentrating pressure on the pads and minimizing pressure application to areas between them.

Implementation Method 1

The clip applies a pressure to the outer face of the fan hub at the clip contact zones to inhibit movement of the fan along the drive shaft

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The drive member applies a pressure to the inner face of the fan hub at the drive member contact zones to inhibit movement of the fan along the drive shaft

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2243962B1Engine cooling fan assembly
Publication Date: 2017.08.02 ROBERT BOSCH GMBH
  • EP2243962B1 patent drawingFigure 1
  • EP2243962B1 patent drawingFigure 2
  • EP2243962B1 patent drawingFigure 3

AI summary

A fan assembly that includes a fan having a fan hub and motor having a drive shaft and a drive member coupled to the drive shaft for rotation with the drive shaft. The fan hub includes an inner face and an outer face. The drive member contacts the inner face of the fan hub to defme a plurality of discrete drive member contact zones between the drive member and the inner face of the fan hub. A clip engages the drive shaft and the outer face of.the fan hub to couple the fan to the drive shaft. The clip contacts the outer face of the fan hub to define a plurality of discrete clip contact zones between the clip and the outer face of the fan hub. The plurality of drive member contact zones are generally aligned with the plurality of clip contact zones.