Steering Gear Floating Bearing Elastic Pivot

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Solution Overview

Problem

Conventional steering gears with helical or worm gears face challenges in noise reduction and mechanical efficiency due to shaft bearings with roller or ball bearings, which are expensive and prone to noise and temperature-related issues, leading to a short service life.

Innovation Solution

A steering gear design featuring a holder with recesses that allow for pivoting movement, providing elasticity and reducing noise, where the roller bearing is mounted in a bracket with a disc-shaped portion that can pivot relative to a ring-shaped portion, and an elastic stop element is used on the floating bearing side to absorb load changes, creating a semi-cardanic or fully cardanic suspension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If roller bearings or ball bearings are used in shaft bearings, then the steering gear can support radial loads, but noise increases and service life decreases due to temperature fluctuations and play

Engineering Contradiction:
Improveradial load supportVSAvoidservice life and noise performance
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent replaces expensive roller/ball bearings with a pivotable bracket made of elastic material that can be easily manufactured and replaced. This elastic bracket absorbs temperature fluctuations and load changes, providing reliable noise-free operation throughout the service life without the complexity and cost of precision ball bearings

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the mechanical parameters of the bearing system by introducing an elastic bracket with defined pivotability. This allows the system to adapt to temperature fluctuations and load variations dynamically, maintaining optimal clearance and reducing noise while supporting radial loads, thereby extending service life

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If roller bearings are mounted directly in the housing, then the structure is simple, but noise occurs during load changes and the service life is short

Engineering Contradiction:
Improvebearing structure simplicityVSAvoidnoise during alternating steering
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent transforms the static bearing structure into a dynamic one by making the bracket pivotable about a vertical axis. This allows the bracket to automatically adjust its position in response to load changes during alternating steering, eliminating noise while maintaining structural simplicity and extending service life

Inventive Principle:
Principle #15Dynamics

3Force

If a fixed bearing with roller bearing is used, then the shaft is supported, but the bearing is susceptible to temperature fluctuations and has relatively large play leading to noise

Engineering Contradiction:
Improveshaft supportVSAvoidsusceptibility to temperature fluctuations
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent introduces an elastic bracket with defined pivotability that can dynamically adjust to temperature fluctuations. The elastic material and pivotable connection allow the bearing structure to expand and contract with temperature changes while maintaining proper clearance, eliminating play and noise while continuing to support the shaft effectively

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

This design significantly reduces noise and improves gear engagement, extending the service life while being cost-effective and adaptable to performance requirements, by introducing defined elasticity and a resilient pivotable connection between the shaft and worm wheel.

Implementation Method 1

an elastic stop element is used on the floating bearing side to absorb load changes

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A steering gear design featuring a holder with recesses that allow for pivoting movement, providing elasticity and reducing noise

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2513503B1Steering gear having a fixed bearing and a floating bearing for a screw pinion
Publication Date: 2017.02.01 ROBERT BOSCH AUTOMOTIVE STEERING
  • EP2513503B1 patent drawingFigure 1
  • EP2513503B1 patent drawingFigure 2a
  • EP2513503B1 patent drawingFigure 2b

AI summary

The invention relates to a steering gear (100) having a screw pinion (30) that can be connected to a drive by means of a shaft (90) and with which a screw gear (40) engages, wherein the steering gear (100) comprises a shaft bearing (50) implemented as a fixed bearing (FL) on the drive side end of the shaft (90), wherein said shaft bearing comprises a first rolling bearing (60) for supporting the shaft (90), wherein the steering gear (100) comprises a bearing device (80) implemented as a floating bearing (LL) on the free end of the screw pinion (30), comprising a second rolling bearing (80) for supporting the screw pinion (30). The shaft bearing (50) on the fixed bearing side has a mounting (51) comprising recesses (52) and an offset (57) allowing a pivot motion (ß) by an annular section (51b) of the mounting (51), assembled to the first rolling bearing (60), wherein the mounting (51) comprises a disc-shaped section (51a) provided with the recesses (52), relative to which the annular section (51b) can pivot, wherein the annular section (51b) is either attached to the outer race (61) of the first rolling bearing (60) and the disc-shaped section (51a) on the housing section (20), or the annular section (51b) is assembled to the inner race (62) of the first rolling bearing (60) and the disc-shaped section (51a) is attached to the shaft (90), whereby the screw pinion (30) is elastically pressed into the screw wheel (40) by the torsion in the transition regions (53).