Compact Steering Mechanism With Center Rack Output
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Solution Overview
Problem
Rack-and-pinion steering systems face issues with structural support, misalignment, increased stress on components, and space constraints, leading to undesirable steering geometry and bump-steer, particularly in smaller vehicles and off-road vehicles.
Innovation Solution
A compact steering mechanism with a center rack input and output member positioned between the ends of the rack, utilizing a pinion shaft with a common center axis, and an output member coupled to tie rod assemblies, which reduces the overall length and weight of the steering assembly, improving alignment and reducing stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If tie rods are coupled at or beyond the ends of the rack, then the steering output is positioned far from the steering input, but this creates an undesirable steep angle of the tie rods and increases stress on components
Solution Approach 1:
The patent introduces an intermediary output member (such as a flange or gear) that couples to the rack at a central position between its ends. This intermediary member serves as a mediator that transfers the steering motion from the rack to the tie rods while maintaining optimal angles, thereby reducing stress on the tie rod assemblies and other steering components.
Solution Approach 2:
Instead of coupling the tie rods directly to the ends of the rack as in conventional systems, the patent inverts the approach by coupling them through an output member positioned at the center of the rack. This inversion of the coupling location optimizes the steering geometry and reduces component stress.
2Reliability
If a lengthy rack is used to achieve proper steering geometry, then the steering system provides adequate support and alignment, but this requires much lateral space leaving little room for other components
Solution Approach 1:
The patent inverts the conventional approach by positioning the steering output at the center of the rack rather than at its ends. This allows for a shorter rack length while maintaining proper steering geometry and alignment, thereby reducing the lateral space required for the steering system.
Solution Approach 2:
The patent changes the positional parameter of the steering output from the rack ends to the rack center. This parameter change enables a more compact rack length while preserving the necessary steering geometry and structural support, thus reducing the overall lateral space requirement.
3Adaptability or versatility
If tie rod couplings are positioned outside the ends of the rack, then the steering system can be configured, but this does not well position the inboard ends of the tie rods at the same lateral position as the inboard ends of the front drive pivots
Solution Approach 1:
The output member acts as an intermediary that enables precise positioning of the tie rod couplings. By providing a central coupling point on the rack, it facilitates proper alignment of the inboard ends of the tie rods with the inboard ends of the front drive pivots, improving the precision of the steering system configuration.
4Weight of moving object
If a center input and output steering mechanism is used, then the overall length and weight of the steering assembly is reduced, but this requires careful positioning of the output member to achieve proper steering geometry
Solution Approach 1:
The output member is designed with multi-functionality, serving as both the structural coupling element and the geometric reference point for tie rod attachment. This universal design simplifies the positioning requirements while achieving proper steering geometry and reducing the overall complexity of the center input-output mechanism.
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 compact steering mechanism enhances steering geometry, reduces bump-steer, and provides improved handling and structural support, making it suitable for smaller vehicles and off-road applications while minimizing weight and space requirements.
Implementation Method 1
The pinion gear is coupled to a pinion shaft... the pinion meshes at approximately the middle portion of the rack
Data Source
AI summary
A compact steering mechanism for steering a vehicle having a steering input being a pinion shaft coupled to a pinion meshing with a rack, and a steering output member coupled to the rack. The pinion is positioned at a middle portion of the rack and the output member is positioned between opposing ends of a rack. The mechanism includes a compact steering housing supporting the pinion shaft and containing the rack-and-pinion. The pinion and pinion shaft have a center axis parallel to an axis of the output member. The output member, being a steering pin and rack carrier, a gear, or a flange, is coupled to left and right tie rod assemblies and wheels for steering the vehicle to improve handling.