Steering Column Plastic Sleeve Minimizes Axial Play
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Solution Overview
Problem
Existing steering column designs with plastic bushings for axial adjustability and impact absorption are complex and prone to play, making them difficult to produce and assemble while maintaining low play and reliable operation.
Innovation Solution
A telescopic bearing system using a thermoplastic plastic sleeve with protrusions and elastic deformation, inserted with a press fit between concentric jacket tubes, ensuring minimal play and secure operation through plastic and elastic deformation, and optionally enhanced with spring elements for additional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plastic bushings are used in steering columns to absorb vibrations and impact energy, then vibration damping and impact absorption are improved, but the bushings do not provide guide function and result in play and rattling
Solution Approach 1:
The patent combines the guide function and bearing function into a single plastic sleeve component. The sleeve features an elongated bearing surface that contacts the inner jacket tube to provide guidance, while simultaneously providing the vibration damping and impact absorption properties of plastic bushings. This merging eliminates the need for separate guide elements and reduces play and rattling.
Solution Approach 2:
The plastic sleeve incorporates a localized bearing surface with specific geometric characteristics (elongated shape) that provides guidance functionality at the critical interface between the inner and outer jacket tubes. This local quality enhancement ensures stable operation while maintaining the overall vibration-damping properties of the plastic material.
2Ease of operation
If complex bearing designs with special support elements are used to ensure low-play support, then operational stability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the essential bearing function from complex multi-element support structures and concentrates it into a single plastic sleeve component. By removing unnecessary support elements and focusing on the critical bearing interface, the design achieves low-play support with minimal complexity, simplifying both the structure and manufacturing process.
Solution Approach 2:
The plastic sleeve serves multiple functions simultaneously: it acts as a guide element, a bearing element, and a vibration-damping component. This multi-functionality eliminates the need for separate specialized support elements, reducing overall device complexity while maintaining operational stability and low-play support.
3Adaptability or versatility
If plastic bushings are used to allow axial displacement and rotation, then adjustability is improved, but play and rattling occur during operation
Solution Approach 1:
The plastic sleeve is designed with dynamic characteristics that allow controlled axial displacement and rotation while maintaining stability during operation. The material properties and geometric configuration enable the sleeve to adapt to movement requirements while damping vibrations and preventing rattling through its inherent plastic deformation capabilities.
Solution Approach 2:
The patent utilizes the viscoelastic properties of the plastic material, where the mechanical parameters (stiffness, damping) change based on the operational state. During axial displacement and rotation, the material exhibits appropriate compliance, while during static operation, it provides rigid support to eliminate play and rattling.
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 simple, cost-effective, and reliable telescopic steering column with minimal play, ensuring secure driver feedback and impact resistance by eliminating rattling and tilting, suitable for adjustable and non-adjustable steering columns.
Implementation Method 1
The bearing of the protrusions is brought about either by a plastic or by an elastic or by a combination of plastic and elastic deformation. In the preferred case, the elastic deformation is brought about by a spring element which acts with a spring effect on the protrusions in the direction of the surface of the inner jacket tube.
Implementation Method 2
the plastic sleeve is inserted into the outer jacket tube with a press fit, and in which the outer jacket tube has at least one opening, in the region of which the plastic sleeve has, on its inner surface, protrusions towards the inner jacket tube or towards a central axis, at which the plastic sleeve is pressed against the outer surface of the inner jacket tube.
Implementation Method 3
the elastic deformation is brought about by a spring element which acts with a spring effect on the protrusions in the direction of the surface of the inner jacket tube.
Data Source
AI summary
Various aspects of the disclosure relate to a steering column for a motor vehicle, comprising a bracket which carries an upper jacket unit and a lower jacket unit, wherein the jacket units surround a steering shaft rotatably mounted therein, and wherein the jacket units comprise an inner jacket tube and an outer jacket tube which surrounds the inner jacket tube at least in some sections, said jacket tubes being mounted such that they can be displaced one inside the other in their axial direction by means of a plastic sleeve made of thermoplastic which is located therebetween. Freedom from play is achieved in that the plastic sleeve is inserted into the outer jacket tube with a press fit, and in that the outer jacket tube has at least one opening, in the region of which the plastic sleeve is pressed against the inner jacket tube by deformation.