Gearwheel Supporting Structure for Tooth Root Stress Reduction

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Solution Overview

Problem

Existing gearwheels with reinforcing structures to counteract material fatigue and cracks suffer from weight increase and increased installation space requirements, limiting their efficiency and inertia, especially in applications like automotive engineering.

Innovation Solution

A gearwheel design with a supporting structure that extends between adjacent teeth, featuring a transition region with a geometric variable that changes steadily along the axial and radial directions, reducing stress concentrations and allowing for a more uniform distribution of mechanical loads, thereby enhancing rigidity and load-bearing capability while maintaining a lightweight and compact size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If massive reinforcing structures are provided on the gearwheel to counteract material fatigue and cracks, then the service life and load-bearing capability are improved, but the weight and installation space requirement increase

Engineering Contradiction:

Improveservice lifeVSAvoidgearwheel weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The supporting structure is positioned specifically at the tooth base regions where stress concentrations occur during operation. This localized reinforcement provides the necessary fatigue resistance and crack prevention exactly where needed, rather than using massive reinforcing structures throughout the entire gearwheel, thereby avoiding unnecessary weight increase while maintaining service life and load-bearing capability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The supporting structure is designed with transition regions that prevent stress concentrations from forming in the first place. By providing these supporting structures at the tooth bases before operational stresses can cause fatigue or cracks, the gearwheel achieves improved service life without requiring excessive reinforcement, thus avoiding weight penalties.

Inventive Principle:

Principle #10Preliminary action

2Reliability

Engineering Contradiction:

Improveservice lifeVSAvoidinstallation space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The supporting structures are localized to the tooth base regions where they are most needed for preventing fatigue and cracks. This concentrated placement provides the necessary reinforcement without extending the overall dimensions of the gearwheel, thereby maintaining compact installation space requirements while improving service life.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If sharp edges or constant radius transitions are used for the reinforcing structure, then the manufacturing is simpler, but stress concentrations occur reducing service life and load-bearing capability

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidservice life

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The transition regions of the supporting structures are designed with curved surfaces instead of sharp edges or constant radius transitions. These curved transition regions smoothly connect the supporting structures to the gearwheel body, preventing stress concentrations that would otherwise occur at sharp transitions. This design maintains manufacturing feasibility while significantly improving service life and load-bearing capability by eliminating stress concentration points.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Reliability

If the geometric variable of the transition region changes steadily, then stress concentrations are reduced and load distribution is more uniform, but the manufacturing precision requirement increases

Engineering Contradiction:

Improveload-bearing capabilityVSAvoidtransition region geometry

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The transition regions utilize curved surfaces with steadily changing geometric variables to achieve smooth stress distribution. While this requires precise manufacturing, the curved geometry can be implemented using standard machining or forming processes, and the steady change in geometric variables provides predictable stress distribution patterns that can be controlled within normal manufacturing tolerances, balancing the precision requirement with the significant improvement in load-bearing capability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS11965588B2Gearwheel with supporting structure

Publication Date: 2024.04.23 HIRSCHVOGEL UMFORMTECHNIK GMBH

AI summary

A gearwheel includes a gearwheel body with teeth arranged around its rotational axis. Two adjacent teeth are connected to one another at their tooth roots via a tooth base. The gearwheel includes a supporting structure which has a supporting region at least one or both axial ends of the respective tooth base, which supporting region extends away from the tooth base between the respective adjacent teeth. The supporting regions are connected directly to the adjacent teeth and the tooth base in each case by way of a transition region. The respective transition region surrounds the supporting region in a manner which extends at least partially and contiguously and has a transition geometry in cross section as viewed in the direction of its extent. A geometric variable of the said transition geometry changes steadily, depending on the supporting region, along an axial and/or radial direction with regard to the rotational axis.