Floating Bearing Steering Gear for Stable Backlash Control
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Solution Overview
Problem
Power-assisted steering systems in vehicles face issues with gear backlash due to component tolerances, thermal expansions, and wear, leading to undesirable noise and increased friction, particularly during alternating steering directions.
Innovation Solution
A floating bearing system for the steering gear, featuring a rotary bearing with an inner ring supporting the helical pinion shaft and an outer ring integrated in a bearing sleeve, which allows for defined pivoting and tilting of the guide element within a retention element, preventing excessive pivoting of the pinion shaft and maintaining consistent basic play over the vehicle's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the pinion shaft is made pivotable with resilient elements to eliminate gear backlash, then noise from alternating steering directions is reduced, but the basic play increases over time due to wear and material settling
Solution Approach 1:
The bearing is segmented into a bearing sleeve and an outer ring connected by multiple torsion webs, allowing the resilient function to be distributed across multiple elastic elements rather than a single pivotable connection
Solution Approach 2:
The torsion webs are pre-twisted during assembly to store elastic energy, creating a resilient restoring action that actively counteracts gear backlash while maintaining stable basic play dimensions throughout the service life
2Adaptability or versatility
If the basic play is increased to accommodate thermal expansions and geometry changes, then adaptability to temperature and material changes is improved, but friction in the tooth arrangement increases undesirably
Solution Approach 1:
The torsion webs are pre-twisted during assembly to store elastic energy, creating a resilient restoring action that actively counteracts gear backlash while maintaining stable basic play dimensions throughout the service life
Solution Approach 2:
The bearing provides dynamic resilience through the elastic torsion webs, allowing the pinion shaft to adapt to thermal and geometric changes while maintaining optimal tooth engagement through the restoring force
3Object-generated harmful factors
If torsion webs are used to provide resilient loading, then gear backlash is eliminated, but the manufacturing complexity increases due to the need to twist and assemble the webs
Solution Approach 1:
The bearing sleeve and outer ring are merged into a single integral component with the torsion webs, eliminating the need for separate assembly steps and simplifying manufacturing while maintaining the resilient function
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 floating bearing system ensures minimal and consistent basic play, reducing noise and friction, while allowing for temperature-related expansions and geometry changes, thereby enhancing the durability and performance of the steering gear.
Implementation Method 1
the outer ring and the bearing sleeve are connected via a plurality of torsion webs which are twisted in the case of rotation of the outer ring relative to the bearing sleeve. After the assembly of the steering gear, the torsion webs are twisted so that the resilient restoring action which is thereby produced brings about the resilient loading of the pinion shaft.
Data Source
AI summary
A floating bearing for a steering gear of a motor vehicle includes a rotary bearing having an inner bearing ring for receiving a screw pinion shaft of the steering gear, and an outer bearing ring built into a bearing sleeve. The bearing sleeve interacts with a guiding element, which interacts with a holding element, such that the bearing sleeve moves relative to the holding element in a first direction oriented radially to the longitudinal axis of the bearing sleeve when the screw pinion shaft is not loaded with torque, and relative movement is prevented when the screw pinion shaft is loaded with torque by moving the bearing sleeve in relation to the holding element in a second direction that is oriented radially to the longitudinal axis and perpendicularly to the first direction, whereby the guiding element is tilted in a guiding opening of the holding element or the bearing sleeve.