Exhaust Flap Coupling Preload for Backlash-Free Shaft Alignment
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Solution Overview
Problem
Existing exhaust gas flaps for internal combustion engines face challenges in ensuring a defined positioning of the drive shaft with respect to the pivot shaft, leading to potential misalignment and backlash during rotary movement.
Innovation Solution
The exhaust gas flap incorporates a coupling assembly with a prestressing element, such as a helical spring, that is axially and circumferentially prestressed to maintain the drive shaft and pivot shaft in a defined position, decoupling the rotary coupling function from the prestressing function, allowing for optimized configuration of components for their respective roles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coupling arrangement is used to connect drive shaft and pivot shaft, then rotational coupling is achieved, but defined positioning and alignment between shafts deteriorates due to backlash and misalignment
Solution Approach 1:
The coupling arrangement is segmented into separate functional components: a first coupling portion for rotational coupling and a second coupling portion for axial positioning. This segmentation allows each component to optimize its specific function without compromising the other, eliminating the trade-off between rotational stability and positioning precision.
Solution Approach 2:
A prestressing element is introduced as an intermediary component between the coupling arrangement and the shafts. This mediator applies axial prestressing force to maintain defined positioning and eliminate backlash, while allowing the coupling arrangement to focus on rotational coupling without compromising positioning precision.
2Device complexity
If the coupling arrangement performs both rotary coupling and prestressing functions, then device complexity is reduced, but manufacturing precision and reliability deteriorate
Solution Approach 1:
The coupling arrangement is divided into distinct functional portions: a first coupling portion dedicated to rotational coupling and a second coupling portion dedicated to axial positioning. This functional segmentation allows each portion to be optimized for its specific task, achieving high manufacturing precision without significantly increasing overall device complexity.
Solution Approach 2:
The prestressing function is extracted from the coupling arrangement and implemented through a separate prestressing element. This extraction allows the coupling arrangement to focus solely on rotational coupling and positioning, while the prestressing element independently ensures defined shaft positioning and eliminates backlash.
3Manufacturing precision
If axial prestressing is applied to the coupling arrangement, then shaft positioning is improved, but thermal decoupling capability deteriorates
Solution Approach 1:
The prestressing element acts as a thermal intermediary that applies axial prestressing force while being designed to minimize thermal conduction. This allows the coupling arrangement to maintain precise shaft positioning through prestressing while the thermal intermediary property prevents heat transfer, preserving thermal decoupling capability.
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 design ensures stable rotational coupling and defined axial positioning of the shafts, preventing backlash and allowing for thermal decoupling, while maintaining mechanical strength and resistance to external influences like corrosion.
Implementation Method 1
a prestressing element, in particular a helical spring, which is supported on the coupling arrangement with respect to one shaft of the drive shaft and pivot shaft
Implementation Method 2
a first coupling portion in rotational coupling positive engagement with the drive shaft and a second coupling portion in rotational coupling positive engagement with the pivot shaft
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 (30) 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 (78) 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 in the direction of the pivot axis (A) onto the other shaft of drive shaft (34) and pivot shaft (14) by means of the pre-tensioning element (78) and is pre-tensioned about the pivot axis (A) with respect to one shaft of drive shaft (34) and pivot shaft (14).