Drag Link Guide Assembly With Torsional Locking and Low Friction
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Solution Overview
Problem
In steer-by-wire steering systems, the absence of a mechanical connection between the steering wheel and drag link poses challenges in supporting and guiding the drag link, requiring a robust, low-friction, and cost-effective drag link guide assembly that can handle high forces and maintain torque transmission while minimizing friction.
Innovation Solution
A drag link guide assembly featuring a slide bushing with a torsional locking mechanism and a housing with a mating structure, where the slide bushing has a circular cylindrical periphery with a plane torsional locking face and outward projections that interact with the housing, preventing relative rotation and ensuring secure torque transmission with minimal friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a mechanical connection between steering wheel and drag link is used, then torque transmission is simplified, but the system cannot achieve steer-by-wire functionality
Solution Approach 1:
The drag link guide assembly is segmented into distinct functional components: a housing providing structural support, a slide bushing enabling linear movement, and a torque transmission mechanism with locking elements. This segmentation allows each component to be optimized independently while collectively achieving the complex steer-by-wire functionality without a direct mechanical connection between steering wheel and drag link.
2Strength
If a robust drag link guide assembly is used to handle high forces, then torque transmission is improved, but friction increases
Solution Approach 1:
A slide bushing acts as an intermediary element between the drag link and the housing, providing a low-friction surface that enables smooth linear movement. The bushing material is specifically selected to minimize friction while the torque transmission is handled separately by the locking elements, thus decoupling the friction-generating linear movement from the torque-transmitting function.
Solution Approach 2:
The patent replaces traditional high-friction mechanical connections with a combination of a slide bushing for linear guidance and a positive locking mechanism for torque transmission. This substitution eliminates the need for continuous friction-based torque transmission, allowing robust torque handling with minimal friction during drag link movement.
3Ease of manufacture
If a simple drag link guide assembly is used, then manufacturing cost is reduced, but the assembly cannot handle high drag link forces
Solution Approach 1:
The assembly is divided into simple, manufacturable components (housing, slide bushing, locking elements) that can be produced using conventional manufacturing processes. The segmentation allows each part to be optimized for its specific function while maintaining overall simplicity, enabling the assembly to handle high forces without requiring a complex monolithic structure.
Solution Approach 2:
The patent employs a composite approach combining a slide bushing (likely polymer or composite material for low friction) with metal locking elements and housing. This composite construction allows each material to be selected for its optimal properties, achieving high force capacity while maintaining ease of manufacture and cost-effectiveness.
Data Source
AI summary
A drag link guide assembly for guiding a drag link comprises a slide bushing and a housing enclosing the slide bushing. The housing comprises a socket portion, into which the slide bushing is inserted. The slide bushing comprises a locating area for the drag link having a substantially circular cylindrical periphery with at least one plane torsional locking face. The slide bushing comprises an outward-pointing structure, which interacts with a mating structure that is provided on the internal surface of the housing. A method for producing a drag link guide assembly is furthermore described.