Segmented Sliding Bearing Bushing for Steering Rod Anti-Rotation
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Solution Overview
Problem
Steer-by-wire systems in motor vehicles face challenges in providing independent radial support and rotation prevention for the steering rod, as existing technologies lack the flexibility to adapt these functions to varying requirements effectively.
Innovation Solution
The sliding bearing is segmented to implement pure sliding and rotation prevention functions separately, with elastic supporting elements, such as curved spring sheets, arranged between these segments to provide radial support and prevent rotation, allowing for optimization of each function independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional rack and pinion connection is used to prevent rotation and support the rack, then rotation prevention and support functions are provided, but the system lacks flexibility to adapt these functions to varying requirements independently
Solution Approach 1:
The sliding bearing is divided into multiple segments (first sliding bearing segment, second sliding bearing segment, third sliding bearing segment) along the axial direction. Each segment can be independently designed to perform specific functions: radial support, rotation prevention, or both. This segmentation allows the system to adapt to different functional requirements by selectively activating or configuring specific segments, while maintaining a manageable overall structure.
Solution Approach 2:
Different segments of the sliding bearing are assigned different local qualities and functions. The first sliding bearing segment is optimized for radial support with appropriate clearance, the second segment for rotation prevention with interference fit or keyway, and the third segment can provide additional support. This local differentiation enables each part to be optimized for its specific function while contributing to the overall system performance.
2Reliability
If the sliding bearing is segmented into different functional segments, then each function can be optimized independently, but the device complexity increases
Solution Approach 1:
The sliding bearing is divided into multiple segments (first sliding bearing segment, second sliding bearing segment, third sliding bearing segment) along the axial direction. Each segment can be independently designed to perform specific functions: radial support, rotation prevention, or both. This segmentation allows the system to adapt to different functional requirements by selectively activating or configuring specific segments, while maintaining a manageable overall structure.
Solution Approach 2:
Multiple sliding bearing segments are combined along the axial direction to form a unified bearing assembly. The segments work together to provide comprehensive support and rotation prevention functions. By merging these segments into a single integrated structure with connecting elements, the design achieves functional optimization while avoiding the complexity of multiple separate components.
3Adaptability or versatility
If elastic supporting elements are used to provide radial support, then the support can be optimized for specific loading conditions, but the manufacturing precision requirements increase
Solution Approach 1:
The elastic supporting elements are designed as curved spring sheets with specific geometric parameters (amplitude, wavelength, width, sheet thickness) that can be adjusted to optimize performance for different loading conditions. By changing these parameters, the bearing can adapt to varying radial loads and support requirements without requiring complex manufacturing processes, as the geometry can be controlled through standard sheet metal forming techniques.
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 solution enables effective radial support and rotation prevention of the steering rod, reducing frictional forces and allowing for adaptable functionality to meet diverse requirements, ensuring efficient operation in steer-by-wire systems.
Implementation Method 1
The supporting elements are composed of an elastic material and can deflect under loading. In a preferred embodiment, the supporting elements consist of a curved spring sheet, which has one or more curves.
Implementation Method 2
The curve is compressed as a function of load during loading and poses a defined resistance to the deformation. In the limiting case, the curve is even completely flattened, thereby giving rise to flat surface contact. Depending on the material and in terms of geometry, the curve should be configured in such a way in the design process that, even when pressed flat, no plastic deformations result and hence the curve rises again almost completely in a reversible manner after the load is relieved.
Data Source
AI summary
The disclosure relates to a steer-by-wire system for a motor vehicle including a steering rod, an electric servo unit configured to move the steering rod, and a sliding bearing which radially supports the steering rod in a housing. The housing, the sliding bearing, and the steering rod have complementary geometries whereby the steering rod is prevented from rotating. The sliding bearing includes multiple segments in the circumferential direction, at least one segment of the multiple segments is a sliding bearing location for the radial support. At least one segment of the multiple segments is a first supporting element configured to prevent rotation in one direction of rotation. At least one segment of the multiple segments is a second supporting element configured to prevent rotation in the opposite direction of rotation.