Handlebar-Steering Column Alignment to Reduce Bump Steer
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Solution Overview
Problem
Conventional vehicle steering systems face misalignment issues between the handlebar, steerable wheels, and Pitman arm, leading to undesirable dynamic effects such as bump steer and directional instability during acceleration or deceleration.
Innovation Solution
A steering system with a handlebar assembly and steering column assembly featuring conical surfaces and angular position limiters, along with a compression element to secure the handlebar assembly to the steering column assembly, and a Pitman arm locking mechanism to ensure proper alignment and minimize misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional alignment process adjusting tie rod length is used, then handlebar and steerable wheels alignment is improved, but Pitman arm misalignment persists causing bump steer and directional instability
Solution Approach 1:
The alignment system is segmented into multiple independent adjustment mechanisms: tie rod length adjustment for handlebar-wheel alignment, and a novel Pitman arm alignment mechanism with adjustable alignment blocks and position limiters. This segmentation allows each component to be optimized independently, resolving the contradiction by enabling precise Pitman arm alignment without affecting handlebar-wheel alignment.
Solution Approach 2:
The patent replaces the conventional fixed Pitman arm mounting system with an adjustable mechanical system featuring alignment blocks, adjustment slots, and position limiters. This substitution enables precise positioning of the Pitman arm relative to the steering column, eliminating misalignment-induced bump steer and directional instability while maintaining reliable vehicle operation.
2Device complexity
If fixed handlebar to steering column connection is used, then structural simplicity is maintained, but alignment precision and stability are compromised
Solution Approach 1:
The connection between handlebar assembly and steering column is transformed from a fixed static joint to a dynamically adjustable connection. The system incorporates angular position limiters that can be positioned at different angles, allowing the connection to adapt to precise alignment requirements while maintaining structural integrity. This dynamic capability enables high alignment precision without excessive structural complexity.
Solution Approach 2:
The patent changes the angular parameter of the handlebar connection to the steering column from a fixed value to an adjustable parameter. By providing multiple angular positions through the position limiter mechanism, the system can optimize the angular alignment precision according to specific vehicle requirements, resolving the contradiction between simplicity and precision.
3Ease of manufacture
If conventional steering system without alignment adjustment is used, then ease of manufacture is maintained, but undesirable dynamic effects like bump steer occur
Solution Approach 1:
The patent implements preliminary alignment adjustment capabilities during the assembly process. The adjustable tie rods, Pitman arm alignment blocks, and angular position limiters are designed to be positioned and secured during initial assembly, enabling precise alignment to be established beforehand. This preliminary action eliminates bump steer and directional instability before the vehicle enters service, maintaining ease of manufacture through straightforward assembly procedures.
Solution Approach 2:
The alignment system is designed to be self-adjusting during normal operation within certain parameters. The compression element and position limiter mechanism allow for automatic maintenance of alignment under varying operational conditions, reducing the need for complex external adjustment mechanisms and simplifying the overall manufacturing process while eliminating harmful dynamic effects.
Data Source
AI summary
A steering system for a vehicle is provided. The steering system has a handlebar assembly and a steering column assembly connected to the handlebar assembly. The handlebar assembly includes a first conical surface and a first angular position limiter. The steering column assembly includes a second conical surface mated with the first conical surface, and a second angular position limiter configured to engage the first angular position limiter to limit an angular position of the handlebar assembly relative to the steering column assembly about a steering axis of the steering system. A compression element engages the handlebar assembly and the steering column assembly to compress the first and second conical surfaces against one another in order to fix the handlebar assembly to the steering column assembly. A plurality of linkages is configured to operatively connect the steering column assembly to at least one ground-engaging member of the vehicle.