Exhaust-Gas Flap Coupling with Spring Preload Retention
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Solution Overview
Problem
Existing coupling arrangements for exhaust-gas flaps in internal combustion engines require complex positive locking engagements to ensure captive retention, which complicates production and assembly.
Innovation Solution
A coupling arrangement using a preload element, such as a helical spring, to hold coupling elements together by generating peripheral and axial forces, allowing rotational coupling projections to engage into open cutouts without the need for direct positive locking, simplifying production and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct positive locking engagement is used between coupling elements, then captive retention is ensured, but device complexity and manufacturing difficulty increase
Solution Approach 1:
A preload element is introduced as an intermediary component between the two coupling elements. This preload element generates preload forces that press the coupling elements against each other, creating frictional locking that prevents axial separation. The mediator approach eliminates the need for complex direct positive locking structures between coupling elements while ensuring reliable captive retention through the intermediate preload mechanism.
Solution Approach 2:
The invention replaces direct mechanical positive locking engagement with a friction-based locking mechanism generated by preload forces. Instead of using interlocking teeth, keys, or other direct mechanical locking features between coupling elements, the system uses normal forces generated by the preload element to create sufficient friction that prevents relative axial movement, thereby substituting a simpler mechanical system for a more complex one.
2Reliability
If direct positive locking engagement is used between coupling elements, then captive retention is ensured, but ease of manufacture decreases
Solution Approach 1:
The preload element serves as a mediator that simplifies the manufacturing and assembly process. By introducing this intermediate component, the coupling elements themselves can be manufactured with simpler geometries (open cutouts instead of closed locking features), and the assembly process becomes more straightforward as the preload element naturally generates the necessary locking forces during installation without requiring precise alignment of complex locking mechanisms.
3Reliability
If axial clamping is used to hold coupling elements, then captive retention is achieved, but ease of operation and assembly decreases
Solution Approach 1:
The preload element is pre-loaded during assembly to generate the necessary normal forces between coupling elements before the assembly is put into service. This preliminary action of pre-applying the locking force during assembly eliminates the need for additional clamping operations or adjustments later, making the assembly process easier and more intuitive while ensuring reliable captive retention from the start.
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
The preload element ensures captive retention of coupling elements without direct axial clamping, facilitating easier assembly and production by allowing preformation of components before joining, while maintaining defined positioning and force transmission.
Implementation Method 1
a preload element for generating a force which acts on the first coupling element and the second coupling element substantially in a peripheral direction with respect to one another and for generating a force which acts in an axial direction between the first coupling element and the second coupling element
Data Source
AI summary
A coupling arrangement is disclosed for the rotational coupling of a drive element of a pivoting drive of an exhaust-gas flap for the exhaust-gas flow of a combustion engine to a pivot shaft rotatable about a pivot axis. A first coupling element has a coupling region coupled to a pivot shaft for rotation about the pivot axis. A preload element generates a force acting on the first coupling element and the second coupling element in a peripheral direction with respect to one another and generates a force acting in an axial direction between the coupling elements. One of the coupling elements includes two radially outwardly extending rotational coupling projections and the other coupling element includes a rotational coupling cutout receiving the projection. The one coupling element is held axially on the other coupling element by the preload element to prevent the projections from moving out of the cutouts.