Steering Gear Wedge Preload Adjustment for Precise Gear Meshing

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Solution Overview

Problem

Existing steering gears in motor vehicles face complexity and difficulty in adjusting preload force due to their design, which complicates structural implementation and precise preload adjustment.

Innovation Solution

A steering gear design with a wedge element and tensioning element that allows for a hinge-like connection between the motor and gearbox housings, enabling a simple and precise adjustment of preload force by pivoting the gear wheels apart using a lever mechanism, with the wedge element inserted between mating surfaces on the housings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If an adjustable wedge arrangement is used to pretension the traction device, then the preload can be adjusted, but the design becomes complex with multiple holding, support, and guide elements

Engineering Contradiction:
Improvepreload adjustment precisionVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pretensioning device is segmented into functionally independent components: the wedge element for generating pretension force, the support element for positioning, and the guide element for directional control. This segmentation allows each component to be optimized for its specific function while reducing overall structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wedge element serves multiple functions simultaneously: it generates pretension force through its geometric shape, acts as a positioning element, and provides guidance through its interaction with the guide element. This multi-functionality reduces the need for separate holding, support, and guide elements

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If the pretensioning device introduces preload force in the area of the connecting line between motor and transmission axes, then the distance can be adjusted, but the structural implementation and precise preload adjustment become complicated

Engineering Contradiction:
Improvepreload adjustment precisionVSAvoidstructural implementation ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The wedge element acts as an intermediary between the support element and the motor/transmission assembly. It converts the vertical support force into horizontal pretension force on the traction device, enabling precise preload adjustment without direct intervention in the connecting line area

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pretensioning device operates in a dimension perpendicular to the connecting line by using the wedge element's geometric shape to convert vertical displacement into horizontal force. This dimensional transformation simplifies structural implementation while maintaining precise preload control

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

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

Enables sensitive and precise adjustment of preload force with minimal effort, protecting the traction mechanism from external influences and simplifying assembly and adjustment, while maintaining optimal tensile stress.

Implementation Method 1

the pretensioning device has a wedge element and a tensioning element, wherein the wedge element has wedge surfaces which converge in a wedge direction transverse to the connecting line and are parallel to the motor axis and gear axis and which interact with corresponding counter surfaces on the motor housing and the gear housing

Methodology Applied
Scientific EffectWedge: Wedge

Implementation Method 2

the motor housing is hinged to the gearbox housing at a distance from the connecting line

Methodology Applied
Scientific EffectHinge: Hinge

Data Source

PatentEP4299416B1Steering gear for a motor vehicle
Publication Date: 2025.10.22 THYSSENKRUPP PRESTA AG
  • EP4299416B1 patent drawingFigure 1~2
  • EP4299416B1 patent drawingFigure 3~4
  • EP4299416B1 patent drawingFigure 5

AI summary

The present invention relates to a steering gear (1) for a motor vehicle. To reduce the effort and enable improved preload adjustment, the invention proposes that the preload device (5) comprises a wedge element (51) and a clamping element (53), wherein the wedge element (51) has wedge surfaces (510, 511) converging in a wedge direction transverse to the connecting line (V) and parallel to the engine axis (G) and transmission axis (G), which interact with corresponding counter surfaces (520, 521) on the engine housing (3) and on the transmission housing (2), and the clamping element (53) is designed to force the wedge element (51) in the wedge direction between the counter surfaces (520, 521).