Ventilation Device Snap-Fit Assembly to Reduce Axial Bulk
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Solution Overview
Problem
Traditional ventilation devices for motor vehicle engines require significant material and space due to screwing means on the central hub, making them bulky and inefficient in compact designs.
Innovation Solution
A ventilation device with a fan propeller and external rotor motor, where the central hub has a frontal wall that is open to receive the rotor in a flush manner, using snap-fitting means on the internal lateral wall and external rotor for secure attachment without additional axial thickness, minimizing components and assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screwing means are provided on the frontal wall of the central hub, then the motor can be fastened to the hub, but the axial bulk of the ventilation device increases and significant material is required
Solution Approach 1:
The invention transitions the fastening mechanism from axial dimension (screws protruding from frontal wall) to radial dimension (snap-fitting means on lateral wall). The snap-fitting means engage radially between the lateral wall of the hub and the rotor, eliminating the need for axial protrusions and thereby reducing axial bulk while maintaining secure fastening.
Solution Approach 2:
The snap-fitting means employ elastically deformable elements that can flex during assembly and then lock into place. This flexibility allows for a compact design without compromising the strength or reliability of the fastening connection between the motor rotor and the central hub.
2Reliability
If screwing means are provided on the frontal wall of the central hub, then the motor can be fastened to the hub, but a significant quantity of material is required to define the frontal wall
Solution Approach 1:
The invention extracts the fastening function from the frontal wall structure and relocates it to the lateral wall. This separation allows the frontal wall to be minimized or opened up (as seen in embodiments where the frontal wall is partially or fully open), significantly reducing the material required for the frontal wall while the fastening function is fulfilled by the snap-fitting means on the lateral wall.
Solution Approach 2:
By moving the fastening mechanism to the radial dimension (lateral wall) rather than the axial dimension (frontal wall), the invention reduces the material requirements for the frontal wall. The snap-fitting means utilize the lateral surface area of the hub and rotor, allowing for a more material-efficient design.
3Reliability
If screwing means with significant thickness are used on the frontal wall, then the motor can be fastened to the hub, but the axial bulk of the ventilation device increases
Solution Approach 1:
The invention resolves the contradiction by shifting the fastening mechanism to the radial dimension (lateral wall engagement) rather than using axial protrusions. This dimensional change allows for a compact axial profile while maintaining secure motor-to-hub fastening through the snap-fitting means.
Data Source
AI summary
A ventilation device includes a fan propeller (3) and a motor (5) with an external rotor (7b) for driving the propeller (3). The propeller (3) includes a central hub (11) having a frontal wall (17) and an internal first lateral wall (21) defining an accommodating housing for the external rotor (7b). The external rotor (7b) has a front part (9) and a second lateral wall (9″) bearing against the internal first lateral wall (21) of the central hub (11). The ventilation device further includes a device for snap-fitting over the internal first lateral wall (21) to secure the external rotor (7b) to the central hub (11).