Steering Feedback Actuator With Variable Wheelbase Gear Mesh

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Solution Overview

Problem

Conventional steering feedback actuators in steer-by-wire systems face issues such as high production costs, complex mechanisms, noise due to gear backlash, and difficulty in securing backlash setting precision, particularly in adjusting the wheelbase.

Innovation Solution

A steering feedback actuator design that includes a housing part, a steering column part, a first gear part, an electric motor part, and a wheelbase variable member, allowing for adjustable backlash by varying the wheelbase between the steering column part and the motor shaft through a mechanism involving a plastic and metal gear engagement, reducing noise by using plastic for the second gear part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional reducer (worm reducer, belt type reducer, or planet gear reducer) is used in the steering feedback actuator, then the actuator can provide steering feedback, but the production cost increases and the structure becomes complex

Engineering Contradiction:
Improvesteering feedback capabilityVSAvoidreducer mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex reducer mechanism from the steering feedback actuator. Instead of using conventional reducers (worm reducer, belt type reducer, or planet gear reducer), the invention directly engages a pinion gear with a rack, removing the intermediate reduction mechanism while maintaining the steering feedback function through direct mechanical coupling between the motor and feedback components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the conventional approach by eliminating the reducer and using direct gear-rack engagement. Instead of reducing motor speed through multiple stages, the system uses a pinion gear directly meshing with a rack to achieve both speed reduction and steering feedback, simplifying the overall structure while maintaining functionality.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If a conventional reducer with gear backlash is used, then the actuator can operate, but noise occurs due to gear backlash

Engineering Contradiction:
Improveactuator operationVSAvoidnoise from gear backlash
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the mechanical engagement parameters by using a pinion gear directly meshing with a rack instead of conventional gear reducers. This direct engagement mechanism reduces backlash and eliminates the noise associated with multi-stage reduction gears, while maintaining operational capability through the linear-to-rotational motion conversion of the rack-and-pinion system.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the pitch of screw thread is limited for wheelbase adjustment, then the structure remains simple, but backlash setting precision cannot be secured

Engineering Contradiction:
Improveadjustment mechanism simplicityVSAvoidbacklash setting precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements a dynamic adjustment mechanism where the wheelbase between the motor shaft and steering column can be varied. This allows the system to dynamically adjust backlash settings by changing the relative position of the pinion gear and rack, enabling precise backlash control without requiring complex fixed-pitch screw threads while maintaining structural simplicity.

Inventive Principle:
Principle #15Dynamics

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 design enables precise adjustment of backlash and reduces noise by utilizing a plastic and metal gear combination, improving the reliability and reducing production costs of the steering feedback actuator.

Implementation Method 1

a wheelbase variable member coupled to the housing part in a way to be capable of advancing and retreating, coupled to the motor housing in a way to come into contact with the motor housing, and configured to vary a wheelbase between the steering column part and the motor shaft by moving the motor housing

Methodology Applied
Scientific EffectMechanical movement:

Implementation Method 2

reducing noise by using plastic for the second gear part

Methodology Applied
Scientific EffectMaterial damping:

Data Source

PatentEP4711236A1Steering feedback actuator
Publication Date: 2026.03.18 HYUNDAI MOBIS CO LTD
  • EP4711236A1 patent drawingFigure 1
  • EP4711236A1 patent drawingFigure 2
  • EP4711236A1 patent drawingFigure 3

AI summary

A steering feedback actuator may include a housing part, a steering column part rotatably accommodated in the housing part, a first gear part coupled to the steering column part and rotated along with the steering column part, an electric motor part including a motor housing that is movably coupled to the housing part and that covers an opening of the housing part and a motor shaft that is rotatably coupled to the motor housing and that comprises a second gear part engaged with the first gear part, and a wheelbase variable member coupled to the housing part in a way to be capable of advancing and retreating, coupled to the motor housing in a way to come into contact with the motor housing, and configured to vary a wheelbase between the steering column part and the motor shaft by moving the motor housing.