Pedestrian Hood Hinge Retention Clip for Flutter Deceleration
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Solution Overview
Problem
Existing pedestrian protection hinge systems face issues with violent 'hood flutter' and increased pedestrian contact acceleration during impacts due to inadequate deceleration mechanisms, and they often fail to maintain the hood in a raised position post-actuation, compromising safety and functionality.
Innovation Solution
A pedestrian protection automotive hinge system featuring a first and second hinge portion interconnected by linkages, an actuator-driven release assembly, and a retention mechanism with a flexible retention clip and tapered retention slot to control hood movement and deceleration, allowing controlled deployment and absorption of impact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the hood hinge uses a rigid stop mechanism to prevent hood movement during pedestrian impact, then the hood position is controlled, but violent hood flutter and increased pedestrian contact acceleration occur due to inadequate deceleration
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a deceleration mechanism with a tapered retention slot and flexible retention clip that gradually absorbs kinetic energy during hood deployment. The tapered geometry provides increasing resistance as the retention pin travels through the slot, cushioning the hood's movement before it reaches the final stopped position, thereby preventing violent flutter and reducing pedestrian contact acceleration.
Solution Approach 2:
The patent utilizes parameter changes by employing a tapered retention slot where the width varies along its length. This geometric parameter change creates a progressive deceleration effect: the narrower section provides greater resistance as the retention pin travels through it, dynamically adjusting the deceleration force based on the hood's position and velocity, thus controlling flutter while maintaining position stability.
2Force
If pyrotechnical actuators are used to raise the hood during pedestrian impact, then the hood can be raised to create a crumple zone, but the actuators release pressure after actuation and cannot maintain the hood in the raised position
Solution Approach 1:
The patent introduces an intermediary retention mechanism consisting of a retention link, retention pin, and retention clip assembly that acts as a mediator between the actuator and the hood. This intermediary system captures and holds the hood in the raised position through mechanical engagement of the retention pin with the retention slot and clip, independent of the actuator's pressure state, thereby solving the position maintenance problem.
Solution Approach 2:
The patent applies segmentation by separating the hood support function into two distinct systems: the actuator system for raising the hood and the retention mechanism for holding it. The retention mechanism is further segmented into the retention link (rotatably mounted to the second member), retention pin (engaging the slot), and retention clip (mounted to the first member), allowing independent operation and reliable position maintenance.
3Ease of operation
If the hood hinge allows free movement of the hood during normal operation, then the hood can open and close smoothly, but the hood lacks controlled deceleration during impact events
Solution Approach 1:
The patent applies dynamics by making the deceleration mechanism conditional and position-dependent. The retention clip is flexible and mounted to allow normal hood movement during everyday operation. During impact events, when the hood reaches certain positions, the retention pin engages the tapered retention slot, dynamically activating the deceleration function only when needed, thus maintaining ease of normal operation while providing controlled deceleration during impacts.
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 system effectively absorbs pedestrian impacts by controlling hood movement and deceleration, reducing 'hood flutter' and pedestrian contact acceleration, while enabling the hood to return to a safe position post-impact, enhancing both safety and functionality.
Implementation Method 1
a flexible retention clip mounted to the first member with the retention slot, the retention clip biased by the retention pin to a position where it abuts the retention pin
Implementation Method 2
an actuator configured to engage the second member and move the second member in relation to the first member in response to a collision input
Implementation Method 3
The system effectively absorbs pedestrian impacts by controlling hood movement and deceleration, reducing 'hood flutter' and pedestrian contact acceleration
Data Source
AI summary
A pedestrian protection automotive hood hinge comprises a release assembly which comprises a retainer supported by one of a first member and a second member and a releasable pin supported by the other of the one of the first and second members. The releasable pin is captured in the retainer in the normally closed position and the normally opened position. An actuator is configured to engage the second member and move the second member upward relative to the first member in response to a collision input. The releasable pin is configured to be released by the retainer in response to the collision input permitting the second member to pivot about a member pin relative to the first member to an opened hood collision position. A retention link with a retention pin moves in a controlled manner during a collision so that the retention pin engages a retention slot. At maximum opening of the hood, the retention pin engages a retention clip adjacent the retention slot and begins to rebound. With continued force exerted by the hood on the retention clip, the retention pin passes through and exits the retention clip and the hood decelerates to a final post collision position.