Steering Column Slide Bearing With Preload for Uniform Braking Torque

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Solution Overview

Problem

Existing steering column plain bearings lack the ability to specify a defined, uniform braking torque, leading to uncomfortable steering feel due to insufficient resistance during manual intervention, as they are optimized for low friction rather than damping or braking.

Innovation Solution

A plain bearing with a prestressing element that applies a defined preload force to the inner ring, increasing frictional force between the bearing surfaces, allowing for adjustable damping or braking torque by varying the prestressing force, using a spring element or adjustment device to achieve this.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the inner ring is designed with low friction properties (using plastics with good sliding properties or surface treatments), then sliding friction is reduced, but braking torque and damping effect are insufficient

Engineering Contradiction:
Improvesliding frictionVSAvoidbraking torque
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The invention changes the parameter of friction by introducing a preload force that acts in the direction of the bearing opening reduction. This preload force increases the contact pressure between the inner ring and steering spindle, thereby increasing the friction force to generate the desired braking torque while maintaining low sliding friction through material selection and surface treatments

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the inner ring is preloaded to increase friction and braking torque, then steering feel is improved, but the preload force cannot be specified with sufficient uniformity and accuracy

Engineering Contradiction:
Improvebraking torqueVSAvoidpreload force uniformity
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The preload element is designed to automatically apply a uniform preload force to the inner ring through its elastic deformation. The element's geometry and material properties are selected to ensure that the preload force is distributed uniformly around the bearing opening, eliminating the need for complex adjustment mechanisms and ensuring consistent braking torque

Inventive Principle:
Principle #25Self-service

3Loss of energy

If the inner ring is made from elastic plastic with radial slot to reduce friction, then sliding friction is minimized, but the bearing becomes excessively loose and offers no noticeable resistance

Engineering Contradiction:
Improvesliding frictionVSAvoidresistance to steering input
Core Design Contradiction:
Loss of energyVSForce

Solution Approach 1:

The invention changes the force parameter by introducing a preload force that acts in the direction of bearing opening reduction. This preload force increases the contact pressure between the inner ring and steering spindle, thereby generating the desired resistance to steering input while maintaining low sliding friction through the elastic plastic material and radial slot design

Inventive Principle:
Principle #35Parameter changes

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 noticeable counter-torque during steering, enhancing the steering feel by allowing for adjustable damping or braking torque, independent of the inner ring's elastic properties, and maintaining consistent performance over the steering column's lifespan.

Implementation Method 1

at least one preload element is arranged such that it exerts a preload force (V) on the inner ring (52) to clamp the inner ring (52) onto the steering spindle (22)... increasing frictional force between the bearing surfaces

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

using a spring element or adjustment device to achieve this... maintaining consistent performance over the steering column's lifespan

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3586019B1Slide bearing for a steering shaft and steering column for a vehicle
Publication Date: 2021.06.09 THYSSENKRUPP PRESTA AG
  • EP3586019B1 patent drawingFigure 1~4
  • EP3586019B1 patent drawingFigure 5~7
  • EP3586019B1 patent drawingFigure 8

AI summary

The invention relates to a sliding bearing (5) for a steering spindle (22) of a steering column (1) for a motor vehicle, comprising an inner ring (52) which has an axially continuous bearing opening (53) for the sliding reception of the steering spindle (22). In order to predetermine a defined, uniform braking torque, it is proposed according to the invention that at least one prestressing element (6) is arranged in such a manner that it exerts a prestressing force onto the inner ring (52) for bracing the inner ring (52) on the steering spindle (22).