Exhaust Flap Coupling Preload for Backlash-Free Shaft Alignment
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Solution Overview
Problem
Existing exhaust gas flaps face challenges in ensuring a defined positioning of the drive shaft with respect to the pivot shaft, leading to potential misalignment and inefficiencies in exhaust gas flow.
Innovation Solution
The implementation of a coupling assembly with a prestressing element, such as a helical spring, that is supported both axially and circumferentially, decouples the rotational coupling and prestressing functions, allowing for optimized configuration of components to maintain a defined positioning of the drive and pivot shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coupling arrangement is used to connect the drive shaft with the pivot shaft, then rotational coupling is achieved, but defined positioning and alignment between the shafts deteriorates due to backlash and misalignment
Solution Approach 1:
The coupling arrangement acts as an intermediary element between the drive shaft and pivot shaft, providing a controlled connection that maintains defined positioning while accommodating thermal expansion and manufacturing tolerances. The coupling includes positive engagement elements that prevent backlash and ensure reliable rotational coupling without rigidly connecting the two shafts.
2Stability of the object's composition
If the coupling arrangement rigidly connects the drive shaft and pivot shaft, then positioning stability improves, but thermal decoupling and tolerance compensation are lost
Solution Approach 1:
The coupling arrangement is segmented into multiple functional elements: positive engagement elements for preventing backlash, spacing elements for maintaining axial distance and enabling thermal expansion, and support elements for bearing loads. This segmentation allows each element to perform its specific function while collectively achieving both positioning stability and thermal decoupling.
3Manufacturing precision
If axial support and preload are applied to the pivot shaft, then defined positioning in the axial direction is achieved, but the coupling arrangement becomes more complex
Solution Approach 1:
The coupling arrangement merges multiple functions into a single integrated structure: rotational coupling through positive engagement, axial support through bearing surfaces, and preload application through the coupling geometry. This merging reduces the need for separate components while achieving precise axial positioning of the pivot shaft.
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 solution ensures stable and defined positioning of the shafts, preventing backlash and misalignment, while allowing for thermal decoupling and compensation of component tolerances, resulting in improved mechanical strength and resistance to corrosion.
Implementation Method 1
a preloading element supported with respect to the coupling arrangement on the one hand and with respect to a shaft of drive shaft and pivot shaft on the other hand, wherein the preloading element preloads the coupling arrangement axially away from one shaft of drive shaft and pivot shaft in the direction of the pivot axis
Data Source
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AI summary
An exhaust flap, in particular for the exhaust flow of an internal combustion engine, comprises a flap tube (12), a flap baffle (16) carried inside the flap tube (12) on a pivot shaft (14) rotatable about a pivot axis (A), a pivot drive (29) for the pivot shaft (14), and a coupling arrangement (36) coupling the pivot shaft (14) with a drive shaft (34) of the pivot drive (29) for common rotation about the pivot axis (A), wherein the coupling arrangement (36) comprises a first coupling area (42) in rotary positive engagement with the drive shaft (34) and a second coupling area (44) in rotary positive engagement with the pivot shaft (14), characterized by a preloading element (58) supported with respect to the coupling arrangement (36) on the one hand and with respect to a shaft of the drive shaft (34) and pivot shaft (14) on the other hand.wherein the coupling arrangement (36) is axially pre-tensioned away from one shaft of drive shaft (34) and pivot shaft (14) in the direction of the pivot axis (A) by the pre-tensioning element (58) and is pre-tensioned about the pivot axis (A) with respect to one shaft of drive shaft (34) and pivot shaft (14).