Dual-Deformability Gear Teeth for Low-Backlash Temperature Compensation

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Solution Overview

Problem

Gear transmissions with gears made of different materials face challenges in maintaining optimal torsional backlash over a wide temperature range due to varying thermal expansion coefficients, leading to either excessive backlash at lower temperatures or insufficient backlash at higher temperatures.

Innovation Solution

A gear design featuring first teeth with one deformability and second teeth with greater deformability, oversized in the circumferential direction, which act like a spring element to maintain low backlash across a wide temperature range without jamming, and can be manufactured with asymmetrical design and different materials for enhanced flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gears are made of different materials to achieve specific functional requirements, then the engagement can be optimized at specific temperatures, but the torsional backlash varies significantly across wide temperature ranges

Engineering Contradiction:
Improveengagement qualityVSAvoidtemperature range adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The gear wheel incorporates two types of teeth with different deformability characteristics: first teeth with normal deformability and second teeth with increased deformability. This local differentiation allows the gear to optimize engagement at different temperature ranges - the first teeth engage at higher temperatures while the second teeth engage at lower temperatures, resolving the contradiction between engagement quality and temperature adaptability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of deformability by designing second teeth with increased deformability compared to first teeth. This parameter change enables the gear to adapt to temperature variations - as temperature decreases, the more deformable second teeth can accommodate thermal contraction better, maintaining acceptable backlash, while at higher temperatures the less deformable first teeth provide stable engagement.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the second teeth are oversized in the circumferential direction to reduce backlash at low temperatures, then low temperature engagement improves, but jamming risk increases at high temperatures

Engineering Contradiction:
Improvelow temperature engagementVSAvoidjamming risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The gear wheel differentiates between first teeth and second teeth in terms of their circumferential dimensions and deformability. The second teeth are oversized only in the circumferential direction and have increased deformability, allowing them to provide low backlash at low temperatures without causing jamming at high temperatures due to their ability to deform.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The second teeth are designed with increased deformability, making them dynamically adaptable to temperature changes. At low temperatures, they maintain their oversized shape to reduce backlash, while at high temperatures, their increased deformability allows them to adjust and prevent jamming, thus resolving the contradiction between reducing backlash and preventing jamming.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If a single tooth design is used for all gears, then manufacturing is simple, but backlash cannot be optimized across wide temperature ranges

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidbacklash consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The gear wheel incorporates two types of teeth with different deformability characteristics: first teeth with normal deformability and second teeth with increased deformability. This local differentiation allows the gear to optimize engagement at different temperature ranges - the first teeth engage at higher temperatures while the second teeth engage at lower temperatures, resolving the contradiction between engagement quality and temperature adaptability.

Inventive Principle:
Principle #3Local quality

4Stability of the object's composition

If teeth are made with uniform deformability, then structural consistency is maintained, but the gear cannot adapt to thermal expansion differences across temperature ranges

Engineering Contradiction:
Improvestructural consistencyVSAvoidthermal adaptability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The gear wheel incorporates two types of teeth with different deformability characteristics: first teeth with normal deformability and second teeth with increased deformability. This local differentiation allows the gear to optimize engagement at different temperature ranges - the first teeth engage at higher temperatures while the second teeth engage at lower temperatures, resolving the contradiction between engagement quality and temperature adaptability.

Inventive Principle:
Principle #3Local quality

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

The design ensures low torsional backlash at both ends of the temperature range, providing optimal engagement and smooth running by adjusting the second teeth's deformability to accommodate temperature variations without interfering with meshing gears.

Implementation Method 1

the second teeth with a second deformability, the second deformability being greater than the first deformability... Due to the increased deformability, the second teeth act like a spring element

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

when the two meshing gears have a significantly different coefficient of thermal expansion, the engagement can be better or worse depending on the current temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3686462B1Toothed wheel for use in a gear transmission, gear pairing of a gear transmission and gear transmission with such a gear pairing
Publication Date: 2021.06.09 IMS GEAR SE & CO KGAA
  • EP3686462B1 patent drawingFigure 1A~1C
  • EP3686462B1 patent drawingFigure 2~4A
  • EP3686462B1 patent drawingFigure 4B~4C

AI summary

The present invention relates to a gear (12) for use in a gear transmission (48), comprising a base body (16) forming a toothed ring (18) with a number of first teeth (20) having a first deformability (v1) and a number of second teeth (22) having a second deformability (v2), wherein the second deformability (v2) is greater than the first deformability (v1). The invention further relates to a gear pair (10) of a gear transmission, comprising such a gear (12) and at least one further gear (14) which can be engaged with or is engaged with the gear (12). The invention also relates to a gear transmission with such a gear pair (10).