Symmetrical Serration Ramps in Progressive Steering Gears

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Solution Overview

Problem

Existing progressive steering systems face challenges in providing a harmonious and safe steering experience while being cost-effective, as conventional tooth geometries often lead to uneven counterforce feedback and increased production complexity.

Innovation Solution

The use of serrated components with uniform flank angles symmetrical relative to a central plane in progressive steering gears, featuring serrated ramps and pinion elements with specific angle configurations, allows for a harmonious and safe steering feel by evenly reporting counterforces back to the steering wheel, and enables cost-effective production through simplified tooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional tooth geometries are used in progressive steering systems, then the steering system can be manufactured with standard tooling, but the counterforce feedback becomes uneven and the steering feel is compromised

Engineering Contradiction:
Improvesteering feel qualityVSAvoidproduction complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies asymmetry by using symmetrical flank angles (equal angles on both sides of the tooth) instead of the conventional asymmetric tooth geometry. This symmetrical design creates uniform counterforce feedback during steering operations, improving steering feel quality while maintaining compatibility with standard manufacturing processes

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the geometric parameters of the tooth flanks by specifying that both flanks have equal angles relative to the tooth centerline. This parameter modification (making both flank angles equal) transforms the conventional asymmetric tooth into a symmetrical tooth form, achieving harmonious steering feel without compromising manufacturability

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If asymmetric tooth geometries are used to optimize steering performance, then steering feedback improves, but production costs increase due to complex tooling requirements

Engineering Contradiction:
Improvesteering feedback qualityVSAvoidtooling complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent reverses the conventional approach by applying symmetry to the tooth flanks (equal angles on both sides), which simplifies the manufacturing tooling while maintaining optimized steering feedback. The symmetrical geometry allows standard tooling to produce consistent, high-quality steering feel without requiring complex custom tooling

Inventive Principle:
Principle #4Asymmetry

3Reliability

If conventional rack and pinion tooth geometries are used, then production processes remain simple, but the steering experience lacks harmony and consistency

Engineering Contradiction:
Improvesteering experience qualityVSAvoidtooth geometry complexity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent modifies the tooth geometry parameters by setting both flanks at equal angles to the tooth centerline, creating a symmetrical tooth form. This parameter change achieves harmonious and consistent steering experience while remaining compatible with existing manufacturing precision capabilities and processes

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4182203B1Progressive steering gear, serrated component, and production method
Publication Date: 2024.09.18 BLESS WERNER
  • EP4182203B1 patent drawingFigure 1~2
  • EP4182203B1 patent drawingFigure 3~4
  • EP4182203B1 patent drawingFigure 5~6

AI summary

The invention relates to a serrated component (10) for use in a progressive steering gear, having a first and a second inclined serration ramp (14, 16). The first and second inclined serration ramp (14, 16) have a plurality of serrations (20, 50) with a respective first flank angle and a second flank angle with respect to a central plane (48) running perpendicularly to the longitudinal direction (34) of the serrated component (10). For at least 50% of the serrations (20, 50) of the plurality of serrations (20, 50), the first flank angle has a single first angular value and the second flank angle has a single second angular value, wherein the first angular value corresponds to the second angular value in a mirrored manner on the central plane (48). The invention additionally relates to a progressive steering gear, to a method for producing a serrated component, and to a method for producing a steering gear.