Vehicle Bonnet Locking Device with Guide Mechanism for Pedestrian Protection
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Solution Overview
Problem
Existing locking devices for motor vehicle front flaps face challenges in implementing a second latching stage for pedestrian protection and collision avoidance due to structural constraints, which often result in collisions with engine components and high torque issues when the front flap is moved backwards.
Innovation Solution
A guide device is integrated on the front flap allowing the locking hook and bracket to move relative to each other, enabling a compact design without additional actuators, maintaining the lock position and angle regardless of displacement direction, and utilizing existing actuators for rearward movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bolt or bracket is made very long to maintain locking engagement when the front flap is moved backwards, then the locking reliability is improved, but the device complexity increases and collision with engine components occurs
Solution Approach 1:
The locking device is divided into two separate components: a locking hook fixed to the front flap and a bracket fixed to the vehicle body. This segmentation eliminates the need for a single long bolt, as each component remains relatively short while maintaining locking engagement through their interaction.
Solution Approach 2:
The locking mechanism transitions from a linear extension (long bolt) to a rotational/dimensional engagement where the locking hook rotates and engages with the bracket. This dimensional change allows the locking components to remain short while achieving reliable engagement through angular movement rather than linear extension.
2Reliability
If a long bolt is used to maintain locking engagement during front flap displacement, then the locking reliability is improved, but high torque occurs in the bolt connection area
Solution Approach 1:
By separating the locking function into a hook-bracket system rather than a single bolt, the torque load is distributed differently. The hook rotates and engages with the bracket, distributing the force across multiple contact points and reducing the concentrated torque on a single long bolt connection.
Solution Approach 2:
Instead of using a bolt that extends forward to engage the locking surface, the invention inverts the approach by using a hook that rotates backward to engage with a bracket. This inversion changes the force application direction and reduces the torque moment arm, thereby reducing the torque in the connection area.
3Adaptability or versatility
If the lock shackle is made larger to accommodate longer displacement paths for greater front elevation, then the front flap elevation capability is improved, but the device complexity and installation space requirements increase
Solution Approach 1:
The locking hook is designed to be rotatable rather than fixed, allowing it to dynamically adjust its position and orientation during the displacement process. This dynamic capability enables the locking mechanism to accommodate larger displacement paths and greater front elevation without requiring a proportionally larger lock shackle structure.
Solution Approach 2:
The locking mechanism utilizes rotational movement in an angular dimension rather than requiring linear extension in the displacement direction. This allows the locking components to remain compact while accommodating complex displacement paths through multi-dimensional motion rather than simple linear scaling.
4Ease of manufacture
If linear guidance is used for the lock shackle, then the guidance simplicity is improved, but the lock angle changes with displacement position
Solution Approach 1:
The locking hook is designed to rotate during displacement, dynamically adjusting its angular position to maintain a constant engagement angle with the bracket. This rotational degree of freedom allows the system to compensate for displacement variations while keeping the lock angle stable, combining simple linear guidance with angular adjustment capability.
Data Source
Figure 1~2
Figure 3~4
AI summary
In the case of a locking device for the bonnet (5) of a motor vehicle, a guide device (7) is arranged on the bonnet (5), wherein an element of the lock, which comprises a locking hook (9) and a clip (11), is in engagement with the guide device (7), and wherein, when the bonnet (5) is closed and locked, the latter can be displaced relative to the locking hook (9) and the clip (11) via the guide device (7).