Vehicle Shutter Rotary Shaft Dual Stop Design
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Solution Overview
Problem
Shutter devices for vehicle heat exchangers face issues with rotary shaft failure due to bending stresses, particularly when the driving flap is in the blocking position and subjected to external forces like wind, leading to potential breakage.
Innovation Solution
Incorporating axially and angularly displaced stops on the rotary shaft, which are supported on final stops of the frame in both blocking and opening positions, distributes forces and eliminates bending stresses, thereby preventing shaft failure in a simple and cost-effective manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single stop is used on the rotary shaft, then the shaft can be simplified in structure, but the shaft is subjected to bending stresses and may break under external forces
Solution Approach 1:
The single stop on the rotary shaft is segmented into two separate stops positioned at different angular locations. This segmentation allows the stops to independently support against different final stops on the frame, creating multiple support points that prevent bending stresses while maintaining structural simplicity.
Solution Approach 2:
The two stops are positioned angularly displaced from each other to provide counterbalancing support forces. When one stop experiences a force, the other stop provides a counteracting support, effectively canceling out bending moments and preventing shaft failure under external loads.
2Ease of operation
If the shaft works under torsion to transmit actuator torque, then the driving flap can be moved, but the shaft becomes a weak element prone to breaking
Solution Approach 1:
The two stops act as intermediary support elements between the rotary shaft and the frame. These stops provide additional support points that share the load, reducing the torsional stress concentration on the shaft while still allowing the shaft to rotate and transmit torque for driving flap movement.
3Productivity
If the driving flap is positioned in the blocking position, then airflow is controlled, but the shaft is subjected to maximum bending stresses from wind forces
Solution Approach 1:
The stops are positioned at specific angular locations on the shaft to provide localized support exactly where needed when the driving flap is in the blocking position. This local quality approach ensures that the stops engage with the frame's final stops to provide targeted support against wind forces, preventing bending stresses at critical locations while maintaining airflow control functionality.
Data Source
AI summary
Shutter device for a front grille of a vehicle that according to one embodiment includes a frame, a driving flap pivotally coupled to the frame and suitable for pivoting between an airflow blocking position and an opening position. The driving flap is coupled to a rotary actuator by a rotary shaft for moving the driving flap. The shaft includes a first stop configured for being supported on a first final stop of the frame when the driving flap is arranged in the blocking position. The shaft also includes a second stop arranged on the shaft, the second stop being axially and angularly displaced with respect to the first stop, and is also configured for being supported on a second final stop of the frame when the driving flap is arranged in the blocking position.