Steering Column Cam Mechanism Resists Strain Rotation
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Solution Overview
Problem
Steering column assemblies in automotive vehicles face issues with undesirable audible clicking noises and potential damage due to rapid rotation of the fixed cam portion when the clamp mechanism is released, caused by stored strain energy, which can lead to unwanted rotation and contact with the clamp bracket.
Innovation Solution
A cam mechanism with a mechanical connection between the fixed cam portion and the support bracket that resists rotational movement until at least 50% of the strain energy is released, using a high lift cam with steep ramp angles and a direct contact with a roughened surface to provide a friction force that exceeds the rotational strain force, along with a soft liner to absorb any remaining energy and prevent noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the clamp mechanism is released to allow adjustment, then the steering column becomes adjustable, but the fixed cam portion rotates rapidly causing clicking noise and potential damage
Solution Approach 1:
The patent applies preliminary anti-action by providing a mechanical connection (such as a detent mechanism, friction connection, or guiding feature) that prevents the fixed cam portion from rotating during the initial release phase. This counteracts the harmful rotational movement before it can occur, eliminating the clicking noise and potential damage while still allowing the clamp to be released for adjustment.
2Ease of operation
If the cam mechanism allows free rotation during release, then the clamp can be unlocked easily, but strain energy causes unwanted rotation and contact with the bracket
Solution Approach 1:
The patent segments the release process into two distinct phases: an initial phase where the mechanical connection prevents rotation and stabilizes the cam portion, and a subsequent phase where rotation is permitted. This segmentation allows the clamp to unlock easily while maintaining rotational stability during the critical initial release period, preventing the harmful effects of uncontrolled rotation.
3Object-affected harmful factors
If the fixed cam portion is constrained during release, then noise and damage are prevented, but the mechanical connection must withstand high forces
Solution Approach 1:
The patent applies preliminary action by designing the mechanical connection to be in place and active before the release phase begins. This pre-positioned connection is specifically designed to handle the high forces generated during initial release, preventing rotation and its harmful effects. Once the strain energy is dissipated and forces reduce, the connection naturally becomes less critical, allowing the system to transition to the unlocked state.
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 effectively reduces or eliminates the clicking noise and potential damage by delaying the rotation of the fixed cam portion until significant strain energy is dissipated, ensuring a controlled release and minimizing wear during adjustment.
Implementation Method 1
a direct contact with a roughened surface to provide a friction force that exceeds the rotational strain force
Implementation Method 2
along with a soft liner to absorb any remaining energy and prevent noise
Implementation Method 3
a cam mechanism with a mechanical connection between the fixed cam portion and the support bracket
Data Source
AI summary
A steering column assembly comprises a steering column shroud comprising an inner and an outer tubular member, a support bracket which is fixed to part of the vehicle, and a clamp assembly which includes a cab mechanism having a fixed portion and a moving portion and a clamp pin which passes through arms of the support bracket, the clamp pin being provided with a first reaction member located towards one end of the pin outside of one arm of the support bracket and a second reaction member located towards the other end of the clamp pin outside of the other arm of the support bracket such that the arms of the bracket are located on the clamp pin between the reaction members and with the cam assembly located between the outside of one arm and one of the reaction members. The fixed cam portion is mechanically connected to the support bracket such that at least during an initial release phase of the clamp assembly the force required to produce a rotational movement of the fixed cam portion relative to the support bracket exceeds any rotational force exerted on the fixed part due to strain energy stored in the assembly.