Motor Vehicle Headlight Frangible Zone Impact Absorption
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Solution Overview
Problem
Current motor vehicle headlamp designs with fusible mounting lugs or frangible zones face challenges in absorbing frontal impacts without causing deformation to surrounding components, such as the front wing, which can prevent door opening and increase repair costs.
Innovation Solution
A headlamp design featuring a frangible zone on the rear part of the housing and a breaking mechanism between the glass and housing, allowing the glass to detach during an impact, with protrusions on the glass and a groove on the housing to facilitate this separation, and fixed support points to prevent recoil, directing impact forces to a rigid front support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fusible mounting lugs are used to allow the housing to move backward during impact, then the headlamp can absorb impact forces, but the required free space behind the housing is incompatible with current installation constraints
Solution Approach 1:
The headlamp housing is divided into multiple parts connected by frangible zones, allowing selective separation during impact. The glass lens separates from the housing, and the housing itself can split into segments that move independently, enabling impact absorption without requiring large rear free space.
Solution Approach 2:
The glass lens is extracted as a separable component from the housing through frangible zones. During impact, the glass detaches from the housing, allowing the housing to move backward independently while the glass remains in place, thus absorbing impact forces without requiring the entire assembly to have large rear clearance.
2Strength
If the headlamp housing moves backward during impact, then impact forces are absorbed, but surrounding components such as the front wing deform and prevent door opening
Solution Approach 1:
The housing is segmented with frangible zones that allow controlled separation into multiple parts during impact. This segmentation directs the impact absorption to specific designated areas rather than allowing uncontrolled backward movement that would deform surrounding components like the front wing.
Solution Approach 2:
The frangible zones act as intermediaries between the glass lens and the housing, and between housing segments. These zones control the separation process, ensuring that impact forces are absorbed in a controlled manner through designated failure paths rather than transmitting forces to surrounding vehicle components.
3Strength
If frangible zones are provided on the housing to allow component parts to penetrate into each other, then impact forces are absorbed, but the same space constraints and component deformation issues occur
Solution Approach 1:
The housing is divided into multiple segments connected by frangible zones positioned strategically to control the separation process. During impact, these zones allow controlled separation that absorbs forces in designated areas, preventing uncontrolled deformation of surrounding vehicle components while maintaining compact installation space.
4Strength
If the headlamp tip crashes onto the front support during impact, then the impact force is directed to a rigid support, but the frangible zone must be precisely positioned at the tip
Solution Approach 1:
The frangible zones are positioned at specific locations on the housing, particularly at the tip area, with locally optimized geometry and thickness. This local quality enhancement ensures that the frangible zones initiate failure at the correct location to direct impact forces onto the front support, while the rest of the housing maintains its structural integrity.
Data Source
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AI summary
A motor vehicle headlight (1), comprising a casing (2) intended to be mounted on the body of the vehicle, a protective window (3) made from a rigid material transparent to light, secured to the front part (2a) of the casing (2), characterised in that said headlight (1) comprises at least one weakened breakable area (Z2b) provided in the rear part (2b) of the casing (2), in that it further comprises at least one breaking means (PD3) arranged at the interface between the rear rim (3c) of the window (3) and the front peripheral rim (2a) of the casing (2), making it possible to release the window (3) from the casing (2) in the event of frontal impact of the headlight (1).