Steering Column Geared Rack Layout for Accurate Axial Position Sensing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing steering column assemblies with absolute position sensors face challenges in accurately sensing the displacement of the lower jacket relative to the column mounting bracket due to simultaneous translational and rotational movements during stow functions, which complicates the integration of a geared rack with the sensor.

Innovation Solution

A geared rack is integrally formed with a bushing and remains stationary relative to the lower jacket, aligning with an absolute position sensor to accurately detect axial position changes despite rotational movements, using wedge bushings for guided translation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a geared rack is used to interface with an absolute position sensor to detect axial position, then measurement precision is improved, but device complexity increases due to the need for the geared rack to remain fixed to the column mounting bracket while articulating with rake motions of the lower jacket

Engineering Contradiction:

Improveaxial position detection accuracyVSAvoidgeared rack integration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system separates the detection function from the moving components by fixing the geared rack to the stationary column mounting bracket, while the absolute position sensor moves with the lower jacket. This segmentation allows the rack to remain fixed while the sensor articulates through rake motions, solving the contradiction between measurement precision and device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The absolute position sensor acts as an intermediary that bridges the stationary geared rack and the moving lower jacket. By placing the sensor on the lower jacket rather than the rack, it mediates between the fixed reference frame and the moving component, enabling accurate axial position detection despite rotational articulations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the lower jacket translates and rotates relative to the column mounting bracket during stow functions, then adaptability is improved, but measurement precision deteriorates due to the difficulty of accurately sensing displacement with simultaneous translational and rotational movements

Engineering Contradiction:

Improvestow function capabilityVSAvoiddisplacement sensing accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical displacement sensing methods with an absolute position sensor that provides direct digital position feedback. This substitution eliminates the complexity of mechanically differentiating between translational and rotational movements, enabling accurate displacement sensing even during simultaneous stow and rake functions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The absolute position sensor serves as an intermediary measurement device that directly measures axial position without being affected by rotational articulations. By mounting the sensor on the lower jacket and having it read from the fixed geared rack, the system cleanly separates the measurement function from the complex combined movements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If an absolute position sensor is mounted to sense lower jacket displacement, then measurement precision is improved, but device complexity increases due to the challenge of integrating the sensor with the translating and rotating lower jacket

Engineering Contradiction:

Improveposition sensing accuracyVSAvoidsensor integration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of mounting the sensor to the stationary bracket and having the target move past it, the patent inverts the arrangement by mounting the sensor to the moving lower jacket and having it read from the fixed geared rack. This inversion simplifies integration because the sensor moves with the component whose position is being measured, eliminating the need for complex mounting mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The lower jacket serves multiple functions: it translates during stow operations, rotates during rake operations, and carries the absolute position sensor. By making the lower jacket a multi-functional component that integrates the sensor, the patent reduces overall device complexity while maintaining measurement precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250346283A1Translating power adjustable steering column with geared rack for an absolute sensor

Publication Date: 2025.11.13 STEERING SOLUTIONS IP HOLDING CORP

AI summary

An axially adjustable steering column assembly includes an upper jacket. The assembly also includes a lower jacket, wherein the upper jacket is received within the lower jacket and is telescopingly adjustable therein, the lower jacket having a position sensor operatively coupled thereto. The assembly further includes a column mounting bracket, wherein the lower jacket translates and rotates relative to the column mounting bracket. The assembly yet further includes a geared rack operatively coupled to the column mounting bracket, the geared rack correspondingly rotatable with the lower jacket, wherein the geared rack is in contact with a gear wheel of the position sensor to detect the axial position of the axially adjustable steering column assembly.