Steer-By-Wire Coupling Rod Support With Low-Friction Anti-Rotation
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Solution Overview
Problem
Steer-by-wire steering systems require an improved bearing and anti-rotation protection for the coupling rod, which is not adequately addressed by traditional rack and pinion steering gears, necessitating a new solution for mounting and protection.
Innovation Solution
A steering gear with a coupling rod supported in a housing by a pressure piece featuring two bearing elements on opposite sides, utilizing a helical gearing and sliding surfaces with a PTFE-coated sliding bronze layer for reduced friction and anti-rotation protection, along with an adjusting device for pretensioning the bearing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional rack and pinion steering gear is used, then bearing support and anti-rotation protection are provided, but the system complexity increases and mounting becomes difficult in steer-by-wire systems
Solution Approach 1:
The pressure piece combines multiple functions into a single component: it provides bearing support for the coupling rod through integrated bearing elements, prevents rotation through a non-circular profile geometry, and enables axial movement. This merging of functions eliminates the need for separate rack and pinion steering gear components, reducing system complexity while maintaining reliability
Solution Approach 2:
The pressure piece serves multiple purposes simultaneously: it acts as a bearing support structure, a rotation prevention mechanism, and a positioning element for the coupling rod. The bearing elements provide rotational support while the non-circular profile prevents unwanted rotation, making the component universal in addressing multiple requirements
2Reliability
If bearing elements are added to the pressure piece, then anti-rotation protection is improved, but friction increases
Solution Approach 1:
The pressure piece features localized bearing elements with PTFE-coated sliding bronze layers at specific contact points with the coupling rod. This local application of low-friction coating provides anti-rotation protection and bearing support only where needed, minimizing overall friction while maintaining reliability
Solution Approach 2:
The bearing elements use composite material construction with PTFE (polytetrafluoroethylene) coating on sliding bronze layers. This composite structure combines the load-bearing capacity of bronze with the low-friction properties of PTFE, reducing harmful friction effects while providing effective anti-rotation protection
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 and effective bearing arrangement and anti-rotation protection for the coupling rod, enhancing the reliability and ease of mounting in steer-by-wire steering systems while maintaining axial mobility and reducing rotational movement.
Implementation Method 1
sliding surfaces with a PTFE-coated sliding bronze layer for reduced friction
Implementation Method 2
a pressure piece presses the steering rack against the pinion by pretensioning
Implementation Method 3
utilizing a helical gearing and sliding surfaces
Data Source
AI summary
A steering gear for a steer-by-wire steering system of a motor vehicle may include a coupling rod which is supported in a steering gear housing and on which a threaded spindle is formed, with the threaded spindle being surrounded by a spindle nut. The threaded spindle and the spindle nut may be part of a helical gearing, and the coupling rod is movable along a longitudinal axis by way of the helical gearing. The coupling rod is movably mounted in the steering gear housing along the longitudinal axis by way of a pressure piece having two bearing elements arranged on opposite sides of the coupling rod in a circumferential direction of the longitudinal axis.