Steer-By-Wire Coupling Rod Support for Anti-Twist Assembly
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Solution Overview
Problem
Steer-by-wire steering systems require a new solution for preventing the coupling rod from twisting and improving mounting, as traditional rack-and-pinion steering gears are eliminated, and existing anti-twist devices are not suitable for easy assembly.
Innovation Solution
A steering gear with a coupling rod mounted in a housing using a pressure piece with diametrically arranged bearing elements, featuring a non-round profile and sliding elements with a low friction coefficient, such as PTFE-coated bronze, to prevent twisting and facilitate axial displacement, along with an adjusting device for prestressing the bearing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional rack-and-pinion steering gear is used, then the coupling rod is supported with anti-twist protection, but the steering system is not suitable for steer-by-wire configurations
Solution Approach 1:
The pressure piece is divided into two separate bearing elements that are arranged diametrically opposite each other. Each bearing element independently supports the coupling rod and provides anti-twist protection through its specific bearing surface geometry, while allowing the coupling rod to displace axially for steer-by-wire operation
Solution Approach 2:
The bearing elements are designed with asymmetric bearing surfaces that are inclined relative to the axial direction of the coupling rod. This asymmetric geometry prevents rotational movement (anti-twist) while still permitting axial displacement, resolving the contradiction between rotation prevention and linear motion capability
2Reliability
If the coupling rod is mounted with a pressure piece for anti-twist protection, then rotation is prevented, but assembly and adjustment are complex
Solution Approach 1:
The pressure piece is segmented into two independent bearing elements that can be positioned and adjusted separately. This segmentation simplifies the assembly process compared to a monolithic pressure piece, as each element can be independently installed and adjusted to achieve proper anti-twist protection
Solution Approach 2:
The two bearing elements serve multiple functions: they provide anti-twist protection through their inclined bearing surfaces, support axial displacement of the coupling rod, and can be independently adjusted for proper positioning. This multi-functionality reduces the need for additional components and simplifies overall assembly
3Reliability
If bearing elements are arranged diametrically to provide anti-twist protection, then rotation is prevented, but friction increases
Solution Approach 1:
The bearing elements are equipped with sliding elements at specific contact locations where the coupling rod bears against them. These sliding elements locally reduce the coefficient of friction at the contact surfaces, allowing the bearing elements to prevent rotation while minimizing energy loss through reduced friction during axial displacement
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 improved anti-twist protection and easy assembly for the coupling rod, ensuring secure rotation and axial displacement while minimizing friction and play, enhancing the reliability and assembly efficiency of the steer-by-wire steering system.
Implementation Method 1
sliding elements with a low friction coefficient, such as PTFE-coated bronze, to prevent twisting and facilitate axial displacement
Data Source
Figure 1
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AI summary
The invention relates to a steering gear (7) with a steer-by-wire steering system (1) of a motor vehicle, having a coupling rod (16) which is supported in a steering gear housing (8) and on which a threaded spindle (12) is formed, said threaded spindle being surrounded by a spindle nut (11), wherein the threaded spindle and the spindle nut are part of a helical gearing (10). The coupling rod (16) can be moved along the longitudinal axis (100) by means of the helical gearing (10), and the coupling rod (16) is movably mounted in the steering gear housing (8) along the longitudinal axis (100) by means of a pressure piece (19), wherein the pressure piece (19) has two bearing elements (20, 21) which are arranged on opposite sides of the coupling rod (16) in the circumferential direction of the longitudinal axis (100).