Vehicle Seatback Rotation Mechanism for Side Impact Protection
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Solution Overview
Problem
Current vehicle impact tests, such as side and oblique impact tests, fail to effectively manage the kinematics of vehicle occupants during cross-vehicle movements, leading to inadequate protection and unfavorable crash test results.
Innovation Solution
An assembly that includes a seatback rotatably supported by a seat bottom, with an active actuator connected to rotate the seatback about a vertical axis towards one side, utilizing a swivel mechanism with a ratchet gear and pawl, and a frangible pin to control rotation, activated by a computer system that detects impacts and commands the actuator to reorient the seatback away from the impact side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the seatback is kept fixed in position during impact, then the structure is simple and stable, but the occupant's cross-vehicle movement cannot be effectively limited
Solution Approach 1:
The seatback is designed to rotate dynamically about a vertical axis in response to impact forces. The rotation mechanism allows the seatback to reorient away from the impact side, converting a static structure into a dynamic protective system that adapts to crash conditions.
Solution Approach 2:
The swivel mechanism with ratchet gear and pawl is pre-configured to automatically engage and control rotation when impact occurs. The frangible pin is pre-positioned to break at a specific force threshold, initiating the protective rotation action before full impact force is transmitted to the occupant.
2Reliability
If an active actuator is added to rotate the seatback, then occupant protection is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The system uses the impact force itself to trigger the protective action. The frangible pin breaks under impact load, automatically releasing the pawl from the ratchet gear, which allows the seatback to rotate in response to the same force that triggered the mechanism, eliminating the need for external sensors or powered actuators.
Solution Approach 2:
The impact force, which is harmful to the occupant, is converted into the activating mechanism for protection. The frangible pin is designed to break at a predetermined force level, transforming the harmful impact energy into the useful action of rotating the seatback away from the impact side.
3Adaptability or versatility
If the seatback rotates freely, then it can adapt to impact from any direction, but control over the rotation is lost
Solution Approach 1:
The swivel mechanism introduces asymmetric constraints to the rotation system. The ratchet gear and pawl allow rotation in one direction (away from impact) while preventing rotation in the opposite direction, creating controlled asymmetric adaptability rather than free rotation in all directions.
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
This solution effectively limits cross-vehicle movement of occupants by redirecting normal forces, enhancing occupant safety during impact tests and improving crash test results by altering the direction of forces applied to the occupant, thereby providing better protection.
Implementation Method 1
The active actuator may include pyrotechnic material
Data Source
AI summary
An assembly includes a seat bottom having a rear and a pair of sides extending in a seat-forward direction from the rear. The assembly includes a seatback rotatably supported by the seat bottom. The assembly includes an active actuator operatively connected to the seatback to rotate the seatback about a vertical axis toward one of the sides of the seat bottom.