Dual-Actuator Steering Column Assembly for Compact Full Stow
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Solution Overview
Problem
Steering column assemblies with significant telescopic travel present packaging challenges, particularly when stowed, as they occupy critical space needed for vehicle energy absorption during barrier events, complicating traditional packaging designs.
Innovation Solution
An axially adjustable steering column assembly with an upper and lower jacket, each telescopingly and translatable relative to each other, utilizing two actuators to control telescoping and translating adjustments, along with sliding wedge bushings and tapered rail slots for guidance, allowing for extended and stowed positions while minimizing footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the steering column is made longer to achieve significant telescopic travel for full stow capability, then the handwheel can be repositioned further away from the driver for autonomous driving mode or other activities, but the column occupies critical space needed for vehicle energy absorption during barrier events
Solution Approach 1:
The steering column is divided into two separate functional segments: an upper jacket that performs internal telescoping and a lower jacket that performs external translating relative to the column mounting bracket. This segmentation allows each segment to be optimized for its specific function, enabling significant total travel distance while maintaining a compact overall footprint when stowed.
Solution Approach 2:
The upper jacket is nested within the lower jacket, with the upper jacket telescopingly adjustable within the lower jacket. This nested configuration allows the steering column to achieve extended telescopic travel when needed while maintaining a compact retracted profile, effectively hiding the length requirement within the nested structure rather than extending it externally.
2Device complexity
If the steering column assembly uses traditional internal stowing mechanism (jacket-in-jacket or triple jacket), then the structure is simple, but the handwheel feedback actuator resides in a critical area needed for vehicle energy absorption during a barrier event
Solution Approach 1:
The stowing mechanism is segmented into two independent actuation systems: a first actuator for internal telescoping of the upper jacket and a second actuator for external translating of the lower jacket. This segmentation distributes the stowing function across separate mechanisms, allowing the handwheel feedback actuator to be positioned outside the critical energy absorption zone while maintaining full stow capability.
Solution Approach 2:
The handwheel feedback actuator is extracted from the traditional critical area within the steering column structure and repositioned to translate with the lower jacket relative to the column mounting bracket. This extraction removes the interference with energy absorption during barrier events while preserving the actuator's functional integration with the steering column system.
3Adaptability or versatility
If the steering column provides significant telescopic travel for stow capability, then the handwheel can be repositioned for autonomous driving mode or driver activities, but packaging challenges arise that complicate traditional design
Solution Approach 1:
The steering column assembly employs dynamic adjustability with two independent actuators that enable continuous position control throughout the telescopic and translating ranges. This dynamic system allows the column to adapt to different driving modes (manual, autonomous, parked) by positioning the handwheel at optimal locations, while the modular actuator design keeps packaging manageable through functional separation.
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 solution provides a stowable steering column assembly that optimizes packaging by reducing the forward footprint during normal driving, creating additional space for energy absorption during collisions, while maintaining functionality and comfort across various driving modes.
Implementation Method 1
a first pair of sliding wedge bushings... disposed within a respective one of the first pair of tapered rail slots
Implementation Method 2
sliding wedge bushings and tapered rail slots for guidance
Data Source
AI summary
An axially adjustable steering column assembly includes an upper jacket. The steering column assembly also includes a lower jacket, wherein the upper jacket is received within the lower jacket and is telescopingly adjustable therein. The steering column assembly further includes a column mounting bracket, wherein the lower jacket is operatively coupled to the column mounting bracket and translates relative to the column mounting bracket. The steering column assembly yet further includes a first actuator operatively coupled to the upper jacket to control telescoping adjustment of the upper jacket relative to the lower jacket. The steering column assembly also includes a second actuator operatively coupled to the lower jacket to control translating adjustment of the lower jacket relative to the column mounting bracket.