Active Pedestrian Hood Hinge with Integrated Latch
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Solution Overview
Problem
Modern motor vehicles with low profile hoods and smaller engine compartments present a challenge for pedestrian protection systems, as they limit the available crush space, necessitating the development of more effective active hinges for deployable hood assemblies that can absorb impact forces efficiently.
Innovation Solution
An active hinge design featuring a pawl and bolt mechanism that requires minimal energy to deploy, utilizing a small actuator stroke to rotate the pawl from a locked to an unlocked position, allowing the hood to move from a non-deployed to a deployed position without the need for a spring, thus preventing noise and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional active hinge with spring mechanism is used to deploy the hood, then the hood can be deployed to create crush space, but the system generates noise and vibrations and requires more energy
Solution Approach 1:
The patent removes the spring mechanism from the active hinge system, extracting the source of noise and vibrations. The deployment function is achieved through an actuator that directly moves the pivot linkage, eliminating the need for spring-based mechanisms that generate harmful acoustic and vibrational effects during operation.
Solution Approach 2:
The patent replaces the spring-based mechanical system with an actuator-driven system. The actuator directly actuates the pivot linkage to deploy the hood, substituting the elastic energy storage and release mechanism (spring) with a controlled actuation system that reduces noise and vibration generation.
2Reliability
If a complex locking mechanism with multiple components is used in the active hinge, then the hood can be securely held in deployed position, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the locking mechanism components into a more integrated assembly. The pawl and bolt are configured to work together as a unified locking system that secures the hood in the deployed position, reducing the number of separate components while maintaining the reliability of the locked state.
Solution Approach 2:
The pivot linkage serves multiple functions: it acts as both the deployment mechanism and the structural support for the locking mechanism. The same linkage that moves the hood into the deployed position also provides the mounting structure for the pawl and bolt, reducing overall system complexity.
3Ease of operation
If a large actuator stroke is used to rotate the pawl from locked to unlocked position, then the hood can be deployed, but the energy consumption increases
Solution Approach 1:
The patent employs a cam mechanism that converts a small linear actuator stroke into a larger rotational movement of the pawl. The cam profile is designed to provide mechanical advantage, allowing the actuator to rotate the pawl from the locked to unlocked position with minimal linear displacement, thereby reducing energy consumption while maintaining full deployment capability.
Data Source
AI summary
An active hinge including a hood bracket for attachment to a vehicle hood and a body bracket for attachment to a vehicle body. A deploy bracket is pivotally attached to the hood bracket and the body bracket. The hood bracket is pivotable relative to the deploy bracket between a non-deployed position and a deployed position. At least one link interconnects, and is pivotally connected to the deploy bracket and the body bracket. A pawl is pivotally mounted to one of the hood bracket, the body bracket, the deploy bracket, and the at least one link. A bolt for engagement by the pawl is connected to another of the hood bracket, the body bracket, the deploy bracket, and the at least one link. An actuator is provided for disengaging the pawl from the bolt to allow the deploy bracket to move relative to the hood bracket and the body bracket.