Steering Column Telescopic Shroud Clamp Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing collapsible steering column assemblies face issues with achieving positive locking to prevent unwanted movement during crashes, as friction alone is insufficient to resist high forces, and inter-engaging teeth can lead to permanent damage if not aligned correctly, occurring in 10% to 20% of adjustment operations.
Innovation Solution
A steering column assembly with a telescopic shroud and clamp mechanism featuring a toothed block and puller system, where the toothed block is designed to engage with a slot having opposing rows of teeth, ensuring positive locking by aligning teeth to prevent rotation and deformation under high loads, and an energy-absorbing mechanism to facilitate controlled collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If friction-based locking is used to prevent movement, then the clamp mechanism can be simple in structure, but it cannot resist high forces of up to 6000N applied during crashes
Solution Approach 1:
The locking mechanism is segmented into multiple independent teeth rows (first row and second row) that can engage separately. This allows the system to distribute the high crash forces across multiple engagement points rather than relying on a single friction-based clamp, thereby increasing force resistance while maintaining reasonable structural complexity.
Solution Approach 2:
The invention transitions from a single-plane friction-based clamp to a multi-dimensional tooth engagement system where teeth engage in both radial and axial directions. The first row of teeth engages radially while the second row engages axially, creating a three-dimensional locking structure that resists high forces more effectively than conventional two-dimensional friction clamps.
2Reliability
If inter-engaging teeth are used for positive locking, then high force resistance is achieved, but tooth-on-tooth misalignment occurs in 10% to 20% of adjustment operations causing permanent damage
Solution Approach 1:
The clamp mechanism is designed to preliminarily engage the first row of teeth before final locking with the second row. This preliminary engagement establishes a stable radial position that guides the subsequent axial engagement, ensuring proper alignment is achieved before full locking force is applied, thereby preventing misalignment damage during adjustment operations.
Solution Approach 2:
The locking process is made dynamic through a two-stage engagement sequence. The first row of teeth engages radially first, allowing the system to dynamically adjust and settle into proper alignment. Then the second row engages axially to complete the locking. This dynamic, sequential process eliminates the static alignment problems that cause tooth-on-tooth misalignment in conventional single-stage systems.
3Force
If massive clamp forces are applied to prevent movement during crashes, then positive locking is achieved, but the steering column assembly cannot collapse telescopically when needed
Solution Approach 1:
The system incorporates a preliminary anti-action mechanism where the first row of teeth engages radially to prevent unwanted movement during normal operation and crashes. However, this same radial engagement serves as a preliminary step that can be overridden by sufficient axial force during controlled collapse, allowing the system to switch between locked and collapsed states based on the direction and magnitude of applied forces.
Solution Approach 2:
The clamp mechanism transitions from a static, always-locked state to a dynamic system that can switch between locked and collapsed states. The two-row tooth engagement creates a conditional locking system where the first row provides radial stability during normal use, but the entire mechanism can dynamically disengage and allow telescopic collapse when subjected to specific crash conditions or controlled adjustment forces.
Data Source
AI summary
A steering column assembly comprises a support bracket, a telescopic shroud having an outer shroud portion and an inner shroud portion, an energy absorbing mechanism that includes a puller, a clamp rail fixed to the inner shroud portion including a slot that extends axially along the inner shroud portion, the slot defining two opposing walls which each carry a row of teeth, the two rows thereby being spaced apart from one another with the teeth extending towards each other; the puller being positioned adjacent the slot, a clamp bolt that extends perpendicular to the shroud, and a toothed block having a row of teeth on each side, the pitch between teeth of each row being equal to, or a whole multiple of, the pitch of the teeth of the corresponding row of the slot. The block is supported by a carrier element that moves in response to rotation of the clamp bolt to move, in turn, the toothed block between a clamped position. A contact face of the puller and a contact face of the toothed block are arranged such that the toothed block is prevented from rotating more than a predetermined amount when forced onto the puller, urging the toothed block into engagement with the teeth of the slot.