Helical Steering Gear Geometry for Higher Load Capacity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional steering gears with helical gears are limited in design and adaptation possibilities due to the requirement that the engagement line must intersect the axis perpendicular, restricting load compensation and performance optimization, which can only be addressed by using higher-quality materials or reducing performance specifications.

Innovation Solution

The engagement line of the helical gear is spaced apart from the axis perpendicular, allowing for increased design variants and improved load-bearing capabilities by adjusting the geometry of the gear wheels and housing, specifically the real pitch module, engagement angle, and helix angle, thereby enhancing the tooth root tension and wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the engagement line intersects the axis perpendicular according to conventional standards, then the helical gear design follows predetermined theories, but the design variants and adaptation possibilities are restricted

Engineering Contradiction:

Improvedesign variants and adaptation possibilitiesVSAvoiddesign constraints

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional requirement by deliberately spacing the engagement line away from the axis perpendicular instead of having it intersect. This inversion of the standard design approach enables new design variants and adaptation possibilities while maintaining proper gear engagement functionality

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the geometric parameter relationship between the engagement line and axis perpendicular from intersection (conventional) to spacing (invention). This parameter change allows optimization of load-bearing capability and tooth root tension while providing greater design flexibility

Inventive Principle:

Principle #35Parameter changes

2Strength

If higher-quality and more expensive materials are used, then load increases arising in later operation can be compensated, but the cost increases

Engineering Contradiction:

Improveload-bearing capabilityVSAvoidmaterial quality and cost

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent changes the geometric configuration of the gear engagement (spacing the engagement line from the axis perpendicular) to optimize load distribution and reduce tooth root tension. This allows achieving improved load-bearing capability through geometric optimization rather than relying solely on higher-quality materials

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality optimization by specifically designing the engagement line position to reduce tooth root tension in critical areas. This targeted geometric adjustment improves load-bearing capability at the tooth root without requiring uniform use of higher-quality materials throughout the entire gear component

Inventive Principle:

Principle #3Local quality

3Strength

If the engagement line intersects the axis perpendicular, then the helical gear can be configured according to standards, but the load-bearing capability and tooth root tension are suboptimal

Engineering Contradiction:

Improvetooth root tension and wear resistanceVSAvoidoptimization possibilities

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent inverts the conventional engagement line configuration by spacing it from the axis perpendicular. This inversion enables optimization of tooth root tension and wear resistance while providing greater adaptability in gear design for different load conditions and performance requirements

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20230211823A1Steering gear for a vehicle having a helical gear, and steering system having such a steering gear

Publication Date: 2023.07.06 ZF FRIEDRICHSHAFEN AG

AI summary

The invention relates to a steering gear (11) for a vehicle having a helical gear (19), the helical gear (19) having a first gear wheel (21) and a second gear wheel (22) which engages with the first gear wheel (21), a first rotation axis (23) of the first gear wheel (21) being aligned so as to be transverse to a second rotation axis (24) of the second gear wheel (22), and an axis perpendicular (25) being aligned so as to be orthogonal to the first rotation axis (23) and to the second rotation axis (24), a smallest spacing between axes (26) between the first rotation axis (23) and the second rotation axis (24) coinciding with the axis perpendicular (25), and an engagement line (33) resulting by means of common contact points (34) of the two mutually engaged gear wheels (21, 22). In order to increase the diversity in terms of variants and/or to improve the adaptation possibilities, the steering gear (11) is characterized in that the engagement line (33) is spaced apart from the axis perpendicular (25).