Rear Body Trailer Hitch Structure for EV Rear Collision Absorption
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Solution Overview
Problem
Small-bodied electric vehicles with rear-wheel drive and a trailer hitch face challenges in absorbing collision energy from behind, particularly when equipped with high voltage components like motors, due to limited impact absorption capability and protection.
Innovation Solution
A vehicle rear body structure design that includes a trailer hitch with specific bracket and mount configurations, allowing for the generation of a rotational moment and controlled deformation to absorb collision energy, protecting the high voltage component by moving it forward during a collision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a trailer hitch is attached to the rear portion of a vehicle body in a small-bodied electric vehicle with rear-wheel drive, then the vehicle can tow trailers, but the collision energy absorption capability from behind is insufficient
Solution Approach 1:
The vehicle rear body is segmented into distinct functional zones: the trailer hitch assembly (including brackets and cross member) is separated from the high voltage component mounting area. This segmentation allows the hitch to absorb collision energy through controlled deformation while the high voltage component remains protected in a separate zone with sufficient clearance.
Solution Approach 2:
A subframe acts as an intermediary structure between the trailer hitch and the high voltage component. The subframe provides a mounting platform for the high voltage component while maintaining a predetermined distance from the trailer hitch, serving as a buffer zone that prevents direct transmission of collision forces to the high voltage component.
2Loss of energy
If the bracket length in the front-rear direction is increased to improve collision energy absorption, then more energy can be absorbed, but the height clearance from the rear side frame to the subframe is reduced
Solution Approach 1:
Instead of increasing bracket length in the front-rear direction (one dimension), the design utilizes the vertical dimension by optimizing the bracket length in the up-down direction. This dimensional shift allows sufficient collision energy absorption while maintaining adequate height clearance to the subframe, preventing interference with the high voltage component.
Solution Approach 2:
The bracket dimensions are optimized with specific parameter values: the bracket length in the up-down direction is set to be greater than a predetermined value for adequate energy absorption, while the bracket length in the front-rear direction is constrained to be less than the height clearance. This parameter optimization resolves the contradiction between energy absorption and clearance requirements.
3Reliability
If the trailer hitch structure is made more robust to protect the high voltage component, then component protection improves, but the device complexity increases
Solution Approach 1:
The high voltage component is extracted from the direct collision path and mounted on a subframe at a predetermined distance from the trailer hitch. This spatial extraction eliminates the need for complex protective structures around the high voltage component, as the distance itself provides protection while maintaining structural simplicity.
Solution Approach 2:
The trailer hitch brackets and cross member are designed to undergo controlled deformation before collision forces reach the high voltage component. This beforehand cushioning through structured deformation absorbs collision energy, protecting the high voltage component without requiring additional complex protective mechanisms.
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
Effectively absorbs collision energy in a short stroke, protecting the high voltage motor and enabling the integration of a trailer hitch in small-bodied electric vehicles.
Implementation Method 1
a rotational moment is generated on a downward side where the trailer hitch being given a collision load from a collision body collides with the rear mount
Implementation Method 2
absorbing a collision load when the collision load is input to a trailer hitch
Data Source
AI summary
A vehicle rear body structure includes rear side frames extending along a front-rear direction, a trailer hitch fixedly provided in the rear side frames, a subframe between the rear side frames, a high voltage component on the subframe, and mounts supporting the high voltage component. The trailer hitch includes brackets fixed to the rear side frames respectively and having a length shorter than a height from the rear side frames to the subframe, a cross member between the brackets, a stay extending downward from the cross member, an arm extending rearward from the stay, a support shaft erecting on the arm, and a hitch ball provided on the support shaft below the rear side frames. The mounts include front mounts and a rear mount. A rotational moment is generated on a downward side where the trailer hitch collides with the rear mount at a collision from behind.