Steering Column Speed-Dependent Damping for Quiet End Stops
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Solution Overview
Problem
Existing adjustable steering columns suffer from unwanted noise and rebound issues due to hard impacts at end stops, and lack a clear defined end position, especially at high adjustment speeds.
Innovation Solution
Incorporating a stop damping device with a speed-dependent damper and a retraction device featuring a force accumulator that ensures a controlled, defined end position by exerting a retraction force to guide the component to the end stop, even at low adjustment speeds, using a friction or fluid damper to absorb kinetic energy and prevent rebound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a buffer made of rubber-elastic material is used to dampen impact noise, then noise reduction is improved, but elastic rebound occurs at high adjustment speeds causing the actuating unit to rebound from the end position
Solution Approach 1:
The patent changes the damping characteristic from elastic (speed-independent) to viscous (speed-dependent). The viscous damping coefficient increases with adjustment speed, providing strong damping at high speeds to prevent rebound while maintaining effectiveness at low speeds. This parameter change resolves the contradiction by making the damping force adaptive to the operating condition.
Solution Approach 2:
The patent replaces the rubber-elastic buffer material with a viscous damping mechanism. Instead of relying on elastic deformation and recovery, the system uses viscous fluid resistance to dissipate kinetic energy. This substitution eliminates the elastic rebound effect while maintaining noise damping capability through controlled energy dissipation.
2Reliability
If a speed-dependent damper is used to prevent rebound, then end position accuracy is improved, but the damper may not provide sufficient damping force at low adjustment speeds
Solution Approach 1:
The patent employs a speed-dependent damping coefficient that varies with adjustment velocity. At low speeds, the damping coefficient is reduced to allow smooth positioning without excessive resistance. At high speeds, the coefficient increases automatically to provide strong damping force that prevents rebound and ensures accurate end positioning. This dynamic parameter adjustment resolves the contradiction between sufficient damping force and smooth low-speed operation.
3Productivity
If the actuating unit is adjusted at high speed, then adjustment time is reduced, but the impact at the end stop increases causing noise and rebound
Solution Approach 1:
The patent replaces traditional elastic damping with viscous damping that is inherently speed-dependent. The viscous damping force automatically scales with the square of the adjustment speed, providing proportional damping that allows high-speed adjustment while preventing excessive impact at the end stop. This substitution enables high productivity without generating harmful impact noise.
Solution Approach 2:
The patent converts the kinetic energy that would otherwise cause harmful impact into useful damping work through the viscous damper. The high-speed movement generates greater damping force, which dissipates the kinetic energy as heat in the viscous fluid, transforming the potentially harmful high-speed impact into a controlled energy dissipation process that protects the end stop and reduces noise.
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 provides a smooth, quiet, and pleasant steering experience by eliminating disruptive rebounds and ensuring a precise end position without elastic restoring forces, enhancing user comfort and safety.
Implementation Method 1
using a friction or fluid damper to absorb kinetic energy
Implementation Method 2
which has a speed-dependent damper
Implementation Method 3
a retraction device which comprises a force accumulator which, when the limiting device is reached, is coupled to the component to be braked
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a steering column (1) for a motor vehicle, comprising a jacket unit (3) which is retained on a support unit (2) and in which a steering shaft (4) is mounted rotatably about a longitudinal axis (L) in an inner jacket (31), which can be adjusted relative to the support unit (2) by an adjustment distance in at least one adjustment direction, wherein at least one limiting device for limiting the adjustment distance is arranged between the inner jacket (31) and the support unit (2), said limiting device having a stop damping device (6, 60) effective in the adjustment direction. According to the invention, the stop damping device (6, 60) has a speed-dependent damper (61) to achieve an improved stop behaviour.