Elastic Gear Connection Layout for Torque Transfer and Deformation Relief

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Solution Overview

Problem

Existing elastic gearings for internal combustion engine applications face limitations in torque transfer and service life due to material weaknesses and deformation loads, particularly in contact regions with the housing components.

Innovation Solution

A gearing system with an elastic gear that features a connection arrangement providing minimal play in the circumferential direction but significant play in the axial and radial directions, allowing for deformation absorption without material weaknesses, using a cylindrical and planar section design with bolts and oblong holes for secure attachment to the housing component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the elastic gear uses a thick hub region fastened on the housing component, then the gear can be securely retained, but the flexibility is reduced and material weaknesses are introduced

Engineering Contradiction:

Improveretention strengthVSAvoidflexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The elastic gear is segmented into a thick hub region for secure retention and thin cross-section regions for flexibility. The connection arrangement is segmented to provide different play characteristics in different directions (rigid in circumferential direction, compliant in axial and radial directions).

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the elastic gear have different local qualities: the hub region has high strength and rigidity for secure fastening, while the toothed section has high flexibility for deformation. The connection arrangement also has local quality differences with rigid circumferential connection and compliant axial/radial connection.

Inventive Principle:

Principle #3Local quality

2Reliability

If the circular spline absorbs the deformation load, then the gear can function, but another material is required and production is complicated

Engineering Contradiction:

Improvedeformation load absorptionVSAvoidproduction complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the deformation load absorption function from a separate circular spline component and integrates it into the elastic gear itself through strategically positioned thin cross-section regions. This eliminates the need for additional materials and simplifies production to a single gear component.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the functions of the elastic gear and the deformation-absorbing circular spline into a single integrated component. The thin cross-section regions within the elastic gear perform both the gear function and the deformation load absorption function, eliminating the need for separate components.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If the circular spline is used to connect sections, then the gear can be assembled, but the contact regions are heavily loaded and service life is limited

Engineering Contradiction:

Improveassembly capabilityVSAvoidservice life

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent incorporates thin cross-section regions within the elastic gear that act as predetermined deformation zones. These regions absorb loads before they can be transmitted to the connection regions, cushioning the connection areas from heavy loading and extending service life.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If the positive or non-positive connection is used, then the gear can be retained, but the transferable torque is limited

Engineering Contradiction:

Improveconnection simplicityVSAvoidtransferable torque

Core Design Contradiction:

Ease of manufactureVSForce

Solution Approach 1:

The connection arrangement transitions from static positive/non-positive connections to a dynamic system where the elastic gear can deform elastically. The thin cross-section regions allow controlled deformation that enables higher torque transfer while maintaining simple bolted connections.

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

This design enhances the gearing's performance in transferring rotating movements by decoupling the elastic gear from the housing in axial and radial directions, enabling deformation without hindrance and improving torque transfer capabilities.

Implementation Method 1

The flexibility of the gear is achieved through regions of thin cross-section within the gear

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a connection arrangement which is rigid in circumferential direction, that is, at least approximately has little play, and at the same time, has a large amount of play in the axial direction and in the radial direction

Methodology Applied

Scientific EffectMechanical constraint with directional play: Mechanical Fastener

Data Source

PatentUS11226027B2Gearing having an elastic gear

Publication Date: 2022.01.18 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

A strain wave gearing, comprising an elastic gear retained by a housing component, wherein a connection between the elastic gear and the housing component has a first play in a circumferential direction and a second play in an axial and radial direction with respect to a center axis of rotation of the elastic gear, wherein the first play is an amount less than the second play.