Retractable Steer-by-Wire Column with Pyrotechnic Energy Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Steer-by-wire steering systems in autonomous vehicles need to be collapsible during impacts to minimize driver injury while maintaining manual control capabilities and providing road feel feedback.
Innovation Solution
A retractable steering column with a telescopic mechanism, electrically powered linear actuators, pyrotechnically actuated energy absorption straps, and a bellcrank lever for height adjustment, allowing for adaptive crash energy absorption by disengaging straps during impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the steering column is made rigid to maintain structural strength and manual control, then the strength and stability are improved, but the driver is more vulnerable to injury during impact
Solution Approach 1:
The steering column transitions from a static rigid structure to a dynamic system with multiple states. The telescopic mechanism allows the column to collapse axially during impact, while the straps can be engaged or disengaged from the retaining member based on crash conditions, enabling the structure to adapt its rigidity dynamically
Solution Approach 2:
The steering column is divided into separable components including the telescopic mechanism with inner and outer tubes, and multiple straps that can independently engage or disengage from the retaining member. This segmentation allows selective energy absorption paths to be activated based on impact characteristics
2Object-affected harmful factors
If the steering column is made collapsible to reduce impact energy transmission, then driver safety is improved, but the manual control capability and road feel feedback are compromised
Solution Approach 1:
The system dynamically adjusts its mechanical properties based on operating conditions. During normal operation, the straps remain engaged with the retaining member, maintaining full structural integrity for precise manual control and road feel feedback. During impact, the pyrotechnical actuator disengages the straps, enabling controlled collapse to absorb impact energy
Solution Approach 2:
The straps act as intermediary elements that can selectively connect or disconnect the telescopic mechanism from the retaining member. This intermediary mechanism allows the system to transition between rigid (normal operation) and collapsible (impact) states without permanently compromising either function
3Device complexity
If a single fixed energy absorption level is used, then the device complexity is reduced, but the adaptability to different crash conditions is limited
Solution Approach 1:
The energy absorption mechanism transitions from a static single-level design to a dynamic multi-level system. The straps can be engaged or disengaged based on impact characteristics, allowing the system to adapt its energy absorption capacity to match different crash scenarios without requiring complex real-time adjustment 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
Enables selective energy absorption levels and maintains manual control and road feel feedback, enhancing safety by adapting to crash conditions.
Implementation Method 1
a pyrotechnically actuated means for disengaging the first retaining member from the first and second straps
Implementation Method 2
means for absorbing the impact energy transmitted between a driver and the steering wheel in a crash
Implementation Method 3
an electric motor connected to the shaft in order to provide a sensation of road feel to the driver
Data Source
AI summary
A steering column for a vehicle includes a telescopic mechanism, a first electrically powered linear actuator, and a means for absorbing the impact energy transmitted between a driver and the steering wheel in a crash. The telescopic mechanism includes substantially coaxial first and second tubular members. The first electrically powered linear actuator controls the longitudinal position of the first tubular member relative to the second tubular member. The means for absorbing the impact energy includes: (1) two or more folded metal straps; (2) at least one strap is fixed at one of its ends to a member which is fusibly connected to the first tubular member and to which is also connected a moving part of the said electrically powered linear actuator; (3) an adjacent edge of each of at least the first and second straps comprising an array of teeth or ramps; and (4) a pyrotechnically actuated means.