Steering Column Bending Strap Energy Absorption
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Solution Overview
Problem
Current steering column assemblies lack effective energy absorption mechanisms during collisions, which can lead to increased trauma for drivers due to the lack of movement and energy dissipation of the steering wheel.
Innovation Solution
The proposed steering column assembly incorporates a bending strap with a jacket and rack portion, a form-fit element, and a locking assembly, which allows the steering shaft to rotate and absorb energy by deforming and potentially tearing the bending strap, thereby moving the steering wheel away from the driver upon impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid steering column assembly is used, then structural strength is maintained, but energy absorption during collision is insufficient leading to increased driver trauma
Solution Approach 1:
The bending strap is divided into distinct portions (jacket portion and rack portion) that can deform independently during collision, allowing energy absorption while maintaining overall structural integrity. The form-fit element with void creates segmented engagement zones that facilitate controlled deformation.
Solution Approach 2:
The bending strap's geometric parameters (thickness, width, curvature) are optimized to control deformation characteristics. The area thickness is specifically designed to be greater than the form-fit element thickness, creating a progressive deformation sequence that absorbs energy while maintaining strength.
2Loss of energy
If the bending strap area thickness is increased to improve energy absorption, then more material is required increasing device complexity
Solution Approach 1:
The bending strap is integrated with the jacket and rack portions to form a unified energy absorption system. The form-fit element combines multiple functions (structural support, deformation control, and engagement mechanism) into a single component, reducing overall device complexity.
Solution Approach 2:
The area of the bending strap is nested within the void of the form-fit element, creating a compact arrangement. The jacket portion and rack portion are positioned in nested relationships, allowing complex functionality within a compact structure.
3Loss of energy
If the steering wheel is allowed to move away from the driver during collision, then energy is absorbed, but the steering function may be compromised
Solution Approach 1:
The locking assembly transitions from a locked state (during normal operation) to an unlocked state (during collision), allowing the steering wheel to move. This dynamic state change enables the system to maintain steering reliability during normal use while absorbing energy during collisions.
Solution Approach 2:
The locking assembly is pre-configured to lock the steering wheel in position during normal operation, preventing unintended movement. Upon collision detection, the locking mechanism releases to allow controlled movement, ensuring steering function is maintained when needed while enabling energy absorption when required.
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 design effectively absorbs and dissipates collision energy, reducing the force exerted on the driver by moving the steering wheel away from the impact point, thereby enhancing safety by reducing the risk of injury.
Implementation Method 1
absorb energy by deforming and potentially tearing the bending strap
Implementation Method 2
absorb energy by deforming and potentially tearing the bending strap, thereby moving the steering wheel away from the driver upon impact
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
One steering column assembly includes a bracket connectable to a vehicle, a jacket with an aperture and a wall thickness at the aperture, a steering shaft supported by the jacket, a locking assembly, a bending strap having jacket and rack portions, and an engaging body irrotatably positioned at least partially inside the aperture. The steering shaft is rotatable relative to the jacket about a longitudinal axis of the steering shaft, and the rack portion overlays and is separated from the jacket portion. The engaging body is coupled to or forms part of the bending strap jacket portion and thereby couples the bending strap rack portion to the jacket. The engaging body has a thickness that extends toward the longitudinal axis past the jacket wall thickness at the aperture. The locking assembly is configured to selectively restrict the rack portion from moving relative to the bracket.