Steering Column Layout With External Feedback Actuator

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Solution Overview

Problem

Steering columns for steer-by-wire systems have a high mass and occupy significant installation space due to their bulky design.

Innovation Solution

The steering column design includes a casing unit with a recess allowing the steering shaft to be driven by a feedback actuator with a drive means positioned outside the casing unit, utilizing a gearbox to connect the drive means to the steering shaft, and featuring a shorter steering shaft that protrudes into the casing unit, reducing mass and installation volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the steering column uses a conventional design with the drive means positioned inside the casing unit, then the structural integrity and protection of components is improved, but the mass and installation space volume increase significantly

Engineering Contradiction:
Improvemass of steering columnVSAvoidstructural complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The drive means (motor) is extracted from the casing unit and positioned externally. This allows the casing unit to be simplified and reduced in size, while the drive means can be mounted separately on the vehicle structure. The transmission elements (belt, pulleys) connect the externally mounted drive means to the steering shaft, achieving weight reduction without complete separation of the drive system from the steering column assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The drive means is relocated from the internal three-dimensional space of the casing unit to an external mounting position on the vehicle structure. This spatial reconfiguration in another dimension (from internal to external mounting) resolves the contradiction by allowing the casing unit to be minimized while maintaining all necessary drive functions through external component placement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of stationary object

If the steering shaft is made longer to extend throughout the casing unit, then the mechanical coupling and stability are improved, but the installation space volume and mass increase

Engineering Contradiction:
Improvelength of steering shaftVSAvoidinstallation space volume
Core Design Contradiction:
Length of stationary objectVSVolume of stationary object

Solution Approach 1:

The drive means is extracted from the casing unit, allowing the steering shaft to be shortened. The transmission elements extend from the externally mounted drive means to the shortened steering shaft, eliminating the need for a long steering shaft that would otherwise need to span the entire internal length of a bulky casing unit.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The drive system is segmented into separate functional components: the drive means mounted externally, the transmission elements (belt and pulleys) as intermediate connectors, and the shortened steering shaft. This segmentation allows each component to be optimized independently, with the steering shaft being as short as necessary while maintaining mechanical coupling through the transmission system.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the feedback actuator is positioned farther from the steering wheel, then the space for actuator mounting is improved, but the installation space volume and design freedom are reduced

Engineering Contradiction:
Improvedesign freedomVSAvoidinstallation space volume
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The feedback actuator is relocated from the vertical dimension (inside the steering column assembly) to an external dimension (mounted on the vehicle structure nearby). This spatial reconfiguration allows the actuator to be positioned closer to the steering wheel in terms of functional proximity while maintaining adequate mounting space, thereby increasing design freedom and reducing overall installation volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The transmission elements (belt and pulleys) act as intermediaries between the externally mounted feedback actuator and the steering shaft. This intermediary connection allows the actuator to be positioned externally with greater design freedom while maintaining effective mechanical coupling to the steering shaft, reducing the need for large internal spaces within the steering column assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration results in a compact, lightweight steering column with increased design freedom, allowing the feedback actuator to be positioned closer to the steering wheel, thereby reducing installation space and mass while providing a realistic steering feel.

Implementation Method 1

a belt which is guided through at least one recess of the outer casing (103) in such a way that the steering shaft (51) can be driven by the output shaft (115) via the belt (114)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the feedback actuator (116, 117, 120) has a drive means (116), in particular an electric motor, which has an output shaft (115)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a gearbox (117, 120) for effectively connecting the drive element to the steering shaft (51)

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3853107B1Steering column and steer-by-wire steering system
Publication Date: 2023.04.12 THYSSENKRUPP PRESTA AG
  • EP3853107B1 patent drawingFigure 1
  • EP3853107B1 patent drawingFigure 2
  • EP3853107B1 patent drawingFigure 3

AI summary

The aim of the invention is to improve a steering column (2, 200, 300) for a steer-by-while steering system (1), comprising a steering shaft (51, 510) which can be connected to a steering wheel, which steering shaft is rotatably mounted about a longitudinal axis (104) in a casing unit (103), wherein a feedback actuator (114, 115, 116, 117, 120, 301, 302, 303, 305) is provided, which is operatively coupled to the steering shaft (51, 510), wherein the casing unit (103) has a length L2 in the direction of the longitudinal axis (104) and the steering shaft (51, 510) projects into the casing unit (103) by a length L1, to the effect that installation space volume and weight are saved. This aim is achieved, according to the invention, in that length L1 is less than length L2.