Steering Device Shear Pin Mechanism for Stable Separating Load
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Solution Overview
Problem
Conventional steering apparatuses face challenges in achieving a stable and consistent separating load during secondary collisions, as the load distribution across the column can vary, leading to instability and increased friction forces.
Innovation Solution
The steering apparatus incorporates a clamp portion with a shearing pin mechanism, a friction plate with an elongate hole, and a resin interposed between the holding member and the inner column to reduce friction and stabilize the separation load, allowing for a more controlled and stable separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional friction-based clamping mechanisms are used to fix the steering column, then the column can be securely held during normal operation, but the separating load becomes unstable and varies during secondary collisions due to load distribution differences and friction force changes
Solution Approach 1:
The patent replaces the conventional friction-based clamping mechanism with a shear pin mechanism. The shear pin connects the inner and outer columns and is designed to shear at a predetermined load, providing a stable and predictable separating load. This mechanical substitution eliminates the instability caused by friction force variations while maintaining secure column fixation during normal operation.
Solution Approach 2:
The patent changes the failure mode parameter from friction-based slippage to shear-based failure. By designing the shear pin with specific material properties and dimensions, the separating load is precisely controlled to occur at a predetermined value. This parameter change ensures consistent and stable separating load characteristics during secondary collisions, eliminating the variability inherent in friction-based systems.
2Strength
If the steering column uses a friction-based clamping mechanism, then the column remains fixed during normal steering, but the column may twist under impact load causing increased separating load and unstable performance
Solution Approach 1:
The patent replaces the friction-based clamping mechanism with a shear pin connection that provides both strong fixation and twist resistance. The shear pin acts as a rigid connector that maintains column alignment and prevents twisting under impact loads, while still allowing controlled separation at the predetermined shear point. This substitution eliminates the column twist issue inherent in friction-based systems.
3Force
If conventional clamping mechanisms are used, then the steering column can be firmly held, but the separating load increases due to friction forces and load distribution variations
Solution Approach 1:
The patent replaces the friction-based clamping mechanism with a shear pin mechanism that provides firm column holding through rigid connection while ensuring consistent separating load. The shear pin maintains strong clamping force during normal operation but shears at a predetermined, consistent load value, eliminating the variability caused by friction force changes and load distribution differences in conventional systems.
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 configuration enables a more stable and lower separating load, preventing column twist and maintaining steering stability even during secondary collisions, while reducing friction forces and ensuring consistent load distribution.
Implementation Method 1
the holding member and the inner column are connected together via a shearing pin, and the shearing pin is sheared into fracture upon receiving a predetermined level of impact force
Implementation Method 2
a resin interposed between the holding member and the inner column to reduce friction and stabilize the separation load
Data Source
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AI summary
A steering apparatus is disclosed, the apparatus including friction plates 23, 24a, 24b clamped by a clamping bolt 10 together with a clamp portion and a vehicle-sided bracket 6 to extend toward a rear side of a vehicle in an axial direction; and a holding member 20 fitted on an inner column 3 and connected to portions, on the rear side of the vehicle, of the friction plates 23, 24a, 24b, the holding member 20 and the inner column 3 being connected together via shearing pins 21a, 21b, the shearing pins being sheared into fracture upon receiving a predetermined level of impact force to enable a more stable and lower separating load to be acquired.