Dry Rotational Damper for Steering Column Locking
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Solution Overview
Problem
Existing locking devices for adjustable steering columns in vehicles suffer from mechanical play and vibrations, leading to rattling noise and undesired snapping back of the actuating lever during locking and releasing, and the use of liquid damping fluids complicates the design and raises acceptance issues in automotive engineering.
Innovation Solution
A dry rotational damper is implemented, where a rotor with radially projecting blades makes frictional contact with a continuous contact track on the housing, utilizing dry friction to dampen rotational movement, eliminating the need for liquid damping fluids and simplifying the design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid damping fluid is used in the rotational damper, then the damping function is reliable and defined, but the design becomes complicated due to sealing requirements and the use of liquids in the vehicle interior is fundamentally to be avoided
Solution Approach 1:
The patent extracts the liquid damping fluid from the system entirely, replacing it with a dry friction-based damping mechanism. The rotor is designed with friction elements that contact the housing directly, eliminating the need for liquid fluid and associated sealing measures while maintaining the damping function through solid-friction-based energy dissipation.
Solution Approach 2:
The patent replaces the hydraulic/mechanical system using liquid damping fluid with a purely mechanical dry friction system. The rotor includes friction elements that slide against the housing, converting rotational kinetic energy into thermal energy through dry friction, thereby substituting the liquid-based damping mechanism with a solid-based alternative.
2Object-generated harmful factors
If mechanical play exists in the clamping system parts, then the actuating lever can vibrate and generate rattling noise, but eliminating play requires tighter tolerances that increase manufacturing complexity
Solution Approach 1:
The patent incorporates a pre-loaded spring mechanism that applies constant force to eliminate mechanical play between clamping parts before operation begins. This preliminary action ensures that all moving surfaces remain in constant contact under controlled pressure, preventing vibration and noise without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The patent changes the operational parameters of the clamping system by introducing controlled elastic deformation through spring elements. This allows the system to accommodate normal manufacturing tolerances while maintaining zero play during operation, as the spring force compensates for minor dimensional variations in the clamping components.
3Ease of operation
If a restoring force acts on the actuating lever during release, then the clamping action can be released, but the restoring force causes undesired snapping back of the actuating lever
Solution Approach 1:
The patent introduces a damping mechanism that dynamically opposes the motion of the actuating lever during release. The rotational damper creates velocity-dependent friction forces that allow the lever to move smoothly to its released position while preventing any snapping back motion, transforming the static restoring force into a controlled dynamic process.
Solution Approach 2:
The patent converts the potentially harmful snapping back motion into a beneficial controlled release by using the restoring force to drive the lever through the damping mechanism. The friction-based damper dissipates the energy of the restoring force as heat, transforming what would be harmful vibration and noise into smooth, controlled motion with quiet operation.
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 dry rotational damper effectively reduces vibrations and noise, provides a reliable damping action, and simplifies manufacturing by eliminating the complexity of sealing measures, while ensuring the rotor is protected from environmental influences.
Implementation Method 1
a rotor with radially projecting blades makes frictional contact with a continuous contact track on the housing, utilizing dry friction to dampen rotational movement
Implementation Method 2
a rotational damper which is coupled to the actuating shaft and which damps a rotational movement of the actuating shaft about its rotational axis
Data Source
AI summary
A locking device for an adjustable steering column for a motor vehicle may include an actuating shaft that is mounted such that it can be rotated about a rotational axis, that is connected to an operative element of a clamping device, and that is coupled to a rotor of a rotational damper. The rotor may be mounted rotatably in a housing and may be capable of being driven rotationally about a rotor axis by the actuating shaft. A rotational movement of the rotor may be damped in at least one rotational direction. The rotor may have at least one blade that projects radially with regard to the rotor axis and that has a contact face that makes frictional contact with a contact track on an inner face of the housing. Such a locking device has an improved rotational damper, is less complicated to manufacture, and has high acceptance in automotive engineering.