Column Tube Switch Module Centering for Sensor Precision
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Solution Overview
Problem
Conventional column tube switch modules in motor vehicles have large tolerances and a complex part structure, which hinder the accurate mounting of high-resolution steering angle sensors due to indirect support and free bearing systems, leading to propagation of errors and increased costs.
Innovation Solution
A column tube switch module with a radially secured stator using a centering device that applies a coaxial force to center the module, supporting a high-resolution steering angle sensor directly on the stator, ensuring minimal axial and radial tolerances and preventing component interference with the sensor's accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the code disc is positioned closer to the bearing of the steering column to shorten the axial tolerance chain, then measurement precision improves, but device complexity increases due to the large number of parts required
Solution Approach 1:
The patent combines the stator and column tube into a single integrated component, eliminating the need for separate mounting parts and reducing the overall part count while maintaining precise positioning of the steering angle sensor
Solution Approach 2:
The column tube serves multiple functions: it provides structural support, acts as a mounting element for the stator, and defines the positioning reference for the steering angle sensor, thereby reducing the need for additional dedicated components
2Ease of manufacture
If the steering wheel sensor system is freely borne in the module with indirect driving, then ease of manufacture improves, but measurement precision deteriorates due to large tolerances from free bearing
Solution Approach 1:
The stator is pre-centered on the column tube during assembly, establishing a fixed reference position before the steering angle sensor is mounted, which prevents tolerance accumulation and ensures precise sensor positioning
Solution Approach 2:
The stator acts as an intermediary component that directly connects the column tube to the steering angle sensor, eliminating indirect driving paths and free bearing conditions that would otherwise introduce tolerances
3Ease of operation
If a conventional centering device with bearing is used to support the column tube switch module, then ease of operation improves during mounting, but manufacturing precision deteriorates due to propagation of errors
Solution Approach 1:
The patent removes the bearing component from the centering device, replacing it with a direct friction-based centering mechanism that eliminates the bearing's tolerance contributions while maintaining the centering function during assembly
Solution Approach 2:
The centering device utilizes the inherent friction between the stator and column tube surfaces to automatically center and secure the assembly, eliminating the need for additional bearing components and reducing tolerance propagation
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 allows for cost-effective manufacturing of the column tube switch module while enabling high-resolution steering angle sensors with reduced tolerances, ensuring accurate data and fault-free mounting of steering angle sensors, and increasing the distance between the column tube and steering spindle without compromising axial tolerance.
Implementation Method 1
a force directed coaxially to the longitudinal axis of the steering spindle moves the column tube switch module in the axial direction as far as an end position and automatically centered in the radial direction
Data Source
AI summary
A column tube switch module is radially and axially fixed to a column tube and is supported at the same time on a bearing arranged on the steering spindle. A centering device secures a stator radially to the column tube when a force is acting coaxially on the longitudinal axis of the steering spindle. A steering angle sensor is provided whose fixed part is connected to the stator-end bearing while its rotating part is held so as to be capable of being driven by the steering wheel hub.