Telescopic Steering Shaft Bearing Bush Vibration Damping
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Solution Overview
Problem
Conventional bearing bushing assemblies in telescopic steering shafts contribute significantly to the transmission of acoustic and mechanical vibrations between the chassis and the driver's cab, compromising both sealing and noise reduction.
Innovation Solution
A bearing bushing assembly featuring an inflexible plastic bearing bushing enclosed by an elastic rubber bushing with radially extending convex ribs and axial sealing lips, providing effective radial and axial damping, and a three-piece design with a retaining cap for enhanced sealing and damping performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bearing bushing assembly with a sealing element is used to connect the inner tube and outer tube in an axially movable and sealing manner, then reliable sealing against moisture and dirt is achieved, but acoustic and mechanical vibrations are significantly transmitted between the chassis and driver's cab
Solution Approach 1:
An elastic damping bushing is introduced as an intermediary element between the bearing bushing and the outer tube. This damping bushing acts as a mediator that transmits necessary mechanical forces while filtering out vibrations and noise, thus resolving the contradiction between maintaining sealing reliability and reducing harmful vibration transmission.
Solution Approach 2:
The bearing bushing assembly combines multiple materials with different properties: a hard bearing bushing for structural support and sealing, and a soft elastic damping bushing for vibration isolation. This composite structure allows the assembly to simultaneously achieve reliable sealing and effective noise reduction by leveraging the complementary properties of different materials.
2Strength
If a hard plastic bearing bushing is used to guide the inner tube in the outer tube, then structural support and sealing are provided, but vibration damping and noise reduction are insufficient
Solution Approach 1:
The bearing bushing is divided into two distinct functional segments: a hard plastic bearing bushing for structural support and sealing, and a separate elastic damping bushing for vibration isolation. This segmentation allows each component to optimize its specific function without compromising the other, resolving the contradiction between structural strength and vibration damping.
Solution Approach 2:
Different regions of the bearing bushing assembly have different material properties tailored to local requirements: the bearing bushing region uses hard plastic for structural support, while the outer region uses elastic material for damping. This local differentiation of material quality allows the assembly to simultaneously provide structural support and vibration reduction.
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
Significantly reduces noise and vibration transmission while maintaining the necessary mechanical coupling for steering feedback, with adjustable damping and sealing properties through material and design variations.
Implementation Method 1
Because the bearing bushing is enclosed by an elastic bushing, and more particularly by a rubber bushing, damping that acts notably in the radial direction is achieved between the bearing bushing and the exterior steering shaft tube (outer tube)
Implementation Method 2
a sealing element, which is molded onto the bearing bushing and made of an elastic plastic material, for connecting the inner tube to the outer tube in an axially movable and sealing manner
Data Source
AI summary
A bearing bushing assembly for a telescopic steering shaft comprises an outer tube and an inner tube, wherein the bearing bushing assembly comprises a bearing bushing, which is seated against the inner tube and made of an inflexible plastic material, and a sealing element, which is molded onto the bearing bushing and made of an elastic plastic material so as to connect the inner tube to the outer tube in an axially movable and sealing manner, the bearing bushing being enclosed by an elastic bushing, which in turn is enclosed by an end section of the outer tube, the outer circumference of the elastic bushing comprising outwardly extending rib-shaped elements, the elastic bushing comprises at least one sealing lip extending in the axial direction.