Steering Column Leadscrew Assembly for Single-Motor Axial Adjustment
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Solution Overview
Problem
Traditional steering column assemblies that require multiple actuators for significant axial movement are costly and require additional packaging space, posing challenges in vehicle design.
Innovation Solution
A single actuator system utilizing a leadscrew with dual thread forms and two trunnions to simultaneously achieve telescoping and translating movements of the steering column components, reducing the need for multiple actuators and minimizing packaging requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple actuators are used to achieve significant axial movement of the steering column, then the steering column can reach both comfort and stow positions, but the cost, weight, and device complexity increase
Solution Approach 1:
The patent combines two separate actuator functions into a single actuator that performs both telescoping (upper jacket relative to lower jacket) and translating (lower jacket relative to column mounting bracket) movements. This is achieved by integrating a leadscrew mechanism with dual thread forms that can simultaneously drive two different trunnions, thereby reducing the total number of actuators from two to one while maintaining full axial movement capability.
Solution Approach 2:
The single actuator is designed with multi-functionality to perform multiple axial adjustment tasks. The leadscrew incorporates first and second thread forms with different pitch values, allowing the same actuator to generate different linear displacements at different locations along its length. This enables one actuator to replace what would traditionally require two separate actuators, achieving both comfort position and stow position adjustments.
2Adaptability or versatility
If multiple actuators are used to achieve significant axial movement, then the full range of motion is obtained, but the packaging space required increases
Solution Approach 1:
By merging the functions of two actuators into one integrated leadscrew-trunnion system, the patent reduces the overall volume required for actuator packaging. The single actuator with dual thread forms occupies less space than two separate actuators would require, while still enabling the lower jacket to translate significantly relative to the column mounting bracket and the upper jacket to telescope relative to the lower jacket.
Solution Approach 2:
The patent employs a nested structure where the upper jacket is received within the lower jacket, and the single actuator mechanism is integrated within the column assembly. The leadscrew passes through both trunnions, and the dual thread forms are nested along the length of the single leadscrew, maximizing space efficiency while achieving significant stow travel.
3Device complexity
If a single actuator is used to control both telescoping and translating movements, then cost and complexity are reduced, but the mechanical design becomes more challenging
Solution Approach 1:
The leadscrew is designed with local quality variations through its dual thread forms. The first portion of the leadscrew has a first thread form with a first pitch, while the second portion has a second thread form with a second pitch. This allows different sections of the same component to have different mechanical properties, enabling the single leadscrew to drive two different trunnions with different movement requirements. This localized differentiation makes the manufacturing process more manageable compared to designing a completely new mechanism.
Solution Approach 2:
The leadscrew is segmented into distinct functional portions along its length. The first thread form region and second thread form region are separated into different portions of the leadscrew, each optimized for driving a specific trunnion. This segmentation allows for modular manufacturing and assembly, where each thread form can be independently machined or formed, reducing the overall manufacturing challenge compared to creating a completely integrated single-function component.
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 single actuator system reduces costs, weight, and complexity while enabling efficient axial adjustment of the steering column, accommodating both comfort and stow positions without increasing packaging space.
Implementation Method 1
A single actuator system utilizing a leadscrew with dual thread forms and two trunnions to simultaneously achieve telescoping and translating movements
Data Source
AI summary
An axially adjustable steering column assembly includes an upper jacket. The steering column assembly also includes a lower jacket, wherein the upper jacket is received within the lower jacket and is telescopingly adjustable therein, wherein the lower jacket is translatable relative to a stationary component. The steering column assembly further includes a single motor controlling rotation of a leadscrew extending therefrom to actuate telescoping axial movement of the upper jacket and translation of the lower jacket. The steering column assembly yet further includes a first thread form region located at a distal portion of the leadscrew relative to the single motor. The steering column assembly also includes a second thread form region located at a proximal portion of the leadscrew relative to the single motor, wherein at least one feature of the first thread form region is different than the second thread form region.