Adjustable Friction Steering Column Mechanism
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Solution Overview
Problem
Existing motor-adjustable steering columns face a trade-off between achieving high rigidity and quick adjustment into or out of the stowage position, as reducing frictional force to facilitate faster movement compromises the structural rigidity and natural frequency of the steering column.
Innovation Solution
A friction means is introduced between the inner and outer casing tubes, allowing for adjustable frictional force, with higher friction in the 'friction position' for rigidity within the comfort position range and lower friction in the 'release position' for faster adjustment, enabling both sufficient rigidity and quick movement without the need for a more powerful actuating drive or complex structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If frictional force between casing tubes is reduced to enable faster adjustment into/out of stowage position, then adjustment speed is improved, but rigidity and natural frequency of the steering column deteriorate
Solution Approach 1:
The friction means is designed to dynamically change the frictional force between the inner and outer casing tubes based on the operational state. During normal operation within the comfort position range, high friction is maintained for rigidity. During stowage operations, the friction means releases to reduce frictional force, enabling fast adjustment without compromising structural integrity during use.
Solution Approach 2:
The friction means alters the friction parameter between the casing tubes according to different operational requirements. By changing the frictional force from high to low based on whether the steering column is in use or stowage mode, the system achieves both rigidity during operation and rapid adjustment during stowage without requiring a more powerful actuating drive.
2Strength
If high frictional force is maintained between casing tubes to ensure rigidity, then structural integrity is improved, but adjustment speed into/out of stowage position deteriorates
Solution Approach 1:
The friction means provides dynamic control over the frictional interaction between casing tubes. It automatically adapts the friction level to the current operational context - maintaining high friction for structural rigidity during normal use, and reducing friction to enable rapid stowage operations when required, thus resolving the speed-rigidity trade-off.
Solution Approach 2:
The system changes the friction parameter between the inner and outer casing tubes based on operational state. The friction means enables the frictional force to be high during comfort position range operations for rigidity, and low during stowage operations for speed, eliminating the need to choose between the two conflicting requirements.
3Speed
If a more powerful actuating drive is used to achieve fast adjustment into/out of stowage position, then adjustment speed is improved, but device complexity and cost increase
Solution Approach 1:
The friction means acts as an intermediary mechanism between the actuating drive and the casing tubes. Instead of increasing the power of the actuating drive, the friction means mediates the force transmission by reducing frictional resistance during stowage operations, enabling fast adjustment with the existing drive capability and avoiding increased complexity and cost.
Solution Approach 2:
The invention converts the harmful effect of friction (which resists movement) into a beneficial control mechanism. The friction means allows friction to be high when needed for rigidity and low when needed for speed, transforming friction from a limiting factor into a controllable parameter that enables fast adjustment without requiring a more powerful actuating drive.
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 solution allows for slow adjustments within the comfort position range with high rigidity and rapid adjustments in and out of the stowage position, maintaining structural integrity while reducing the power requirements of the actuating drive, resulting in a simpler, lighter, and more cost-effective steering column design.
Implementation Method 1
a friction means (8), by which a frictional force can be applied between outer casing tube (41) and inner casing tube (42) with regard to relative displacement and which is adjustable between a release position and at least one friction position
Data Source
AI summary
A motor-adjustable steering column including a supporting unit which is connectable to a vehicle body and by which an actuating unit is held which includes a steering spindle mounted in a casing unit to be rotatable about a longitudinal axis. The casing unit has an outer casing tube, in which an inner casing tube is accommodated to be axially displaceable telescopically in the direction of the longitudinal axis. An actuating drive is connected to the inner casing tube and the outer casing tube by which the inner casing tube may be displaced axially in and out relative to the outer casing tube. A feature arranged between the outer casing tube and the inner casing tube generates a frictional force between outer casing tube and inner casing tube with regard to relative displacement which is adjustable between a release position and at least one friction position.