Vehicle Frame Side Impact Absorber Design
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Solution Overview
Problem
Conventional vehicle frames, particularly those of hybrid and electric trucks, face challenges in withstanding side impacts without compromising the integrity of the battery pack, as existing designs often result in contact between the side rail and the battery pack during collisions, leading to potential damage and increased weight through rudimentary upsizing of the side rails.
Innovation Solution
The integration of a multi-member side impact absorber system, featuring a wave-form shaped member and a stiffer reinforcing member, which are secured to the side rail to create distinct energy-absorbing load paths, preventing the side rail from deflecting towards the battery pack during side impacts and maintaining clearance between the side rail and the battery pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the side rail is upsized to prevent deflection during side impact, then the side impact protection is improved, but the vehicle weight increases
Solution Approach 1:
The side impact protection system is segmented into multiple functional components: the side rail, side impact absorber, energy-absorbing member, and battery pack housing. This segmentation allows each component to perform its specific function optimally without requiring the entire side rail structure to be oversized, thereby reducing unnecessary weight while maintaining protection effectiveness.
Solution Approach 2:
The side impact absorber acts as an intermediary component between the side rail and the battery pack. It includes an energy-absorbing member that deflects under impact forces, allowing controlled movement away from the battery pack, and a second member that provides structural support. This intermediary mechanism protects the battery pack without requiring the side rail itself to be substantially oversized.
2Reliability
If the side rail is upsized to maintain clearance from the battery pack during side impact, then the battery pack protection is improved, but the vehicle package size increases
Solution Approach 1:
The side impact absorber incorporates dynamic elements that allow controlled movement during impact. The energy-absorbing member is configured to deflect away from the battery pack under impact forces, dynamically adjusting the clearance distance. This dynamic response maintains battery pack protection while minimizing the overall package size compared to static oversized rail designs.
Solution Approach 2:
The system changes the physical state and position of components during impact. The energy-absorbing member transitions from a neutral position to a deflected position, changing the clearance parameter dynamically. This parameter change allows the system to maintain protection reliability while keeping the vehicle package size compact during normal operation.
3Strength
If a single robust side rail design is used, then the structural strength is improved, but the energy absorption capability is reduced
Solution Approach 1:
The side impact protection system is divided into distinct functional segments: the side rail for structural strength, the side impact absorber with energy-absorbing member for energy dissipation, and the battery pack housing for final protection. This segmentation allows the side rail to maintain high structural strength while the dedicated energy-absorbing components handle crash energy, preventing energy transfer to the battery pack.
Solution Approach 2:
The side impact absorber serves as an intermediary that absorbs and dissipates crash energy before it reaches the battery pack. The energy-absorbing member is specifically designed to deform and absorb energy, while the second member provides structural support. This intermediary mechanism allows the side rail to maintain structural strength without directly absorbing all the impact energy, improving overall energy absorption capability.
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 side impact absorber system effectively absorbs crash energy, inhibiting side rail deflection and preventing contact with the battery pack, thus enhancing side impact protection without increasing the side rail's cross-sectional size or weight, while maintaining the vehicle's package size and efficiency.
Implementation Method 1
a first member of the side impact absorber is secured to the outboard sidewall of the first side rail to define a first energy-absorbing load path to the first side rail in the event of a side impact, the first member having a wave-form shape
Implementation Method 2
a second member of the side impact absorber is secured to the outboard sidewall of the first side rail, nearer the bottom wall than the first member of the side impact absorber, the second member defining a second energy-absorbing load path from the outboard end of the side impact absorber to the first side rail
Data Source
AI summary
A vehicle frame for a hybrid or electric vehicle includes a pair of longitudinally-extending side rails being positioned in spaced relation across a width direction of the vehicle frame to define a battery space therebetween. A side impact absorber is positioned on a first one of the pair of longitudinally-extending side rails. A first member of the side impact absorber is secured to an outboard sidewall of the first side rail to define a first impact energy-absorbing load path to the first side rail. The first member has a wave-form shape and extends laterally outward from the outboard sidewall to an outboard end of the side impact absorber. A second member of the side impact absorber is secured to the outboard sidewall of the first side rail, further from a height-wise center thereof, the second member defining a second impact energy-absorbing load path from the outboard end of the side impact absorber to the first side rail.