Variable-Deformability Gear Teeth for Thermal Backlash Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gearings with toothed gears made of different materials or having different thermal expansion coefficients face challenges in maintaining optimal engagement over a wide temperature range, leading to varying circumferential backlash, which can result in either too little or too much backlash depending on the temperature.
Innovation Solution
A toothed gear design featuring first teeth with a lower deformability and second teeth with higher deformability and oversize, specifically in the circumferential direction, to maintain low backlash across a temperature range without jamming, using thermoplastic materials and strategically positioned connection webs to enhance deformability and prevent noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gear tooth profile is optimized for optimal engagement at a specific temperature, then engagement quality is improved at that temperature, but engagement quality deteriorates at other temperatures in the operating range
Solution Approach 1:
The gear is divided into two distinct tooth types: first teeth with standard dimensions and second teeth with increased circumferential dimensions. This segmentation allows each tooth type to serve different temperature conditions, with the second teeth providing compensation for thermal expansion variations without affecting the overall gear structure
Solution Approach 2:
Different regions of the gear have different tooth properties. The second teeth are specifically designed with increased deformability and oversize in the circumferential direction, creating local quality variations that enable temperature compensation while maintaining standard engagement characteristics in other regions
2Manufacturing precision
If the second teeth are given oversize to maintain low backlash at lower temperatures, then backlash is reduced, but the risk of jamming increases at higher temperatures
Solution Approach 1:
The second teeth are designed with increased deformability, allowing them to dynamically adapt their engagement characteristics based on temperature conditions. At lower temperatures, their oversize compensates for backlash, while at higher temperatures, their flexibility allows them to deform and prevent jamming, providing dynamic adjustment without active control
Solution Approach 2:
The key parameter changed is the deformability of the second teeth, achieved through material selection (thermoplastic) and geometric design (connection webs). This parameter change enables the teeth to adjust their effective dimensions in response to temperature changes, maintaining optimal engagement across the operating range
3Manufacturing precision
If the gear uses materials with different thermal expansion coefficients to achieve desired engagement at operating temperature, then engagement is optimized at that temperature, but backlash varies significantly across the temperature range
Solution Approach 1:
The invention explicitly utilizes thermal expansion effects by designing the second teeth with increased deformability and oversize. These teeth are intended to deform in response to temperature changes, compensating for the thermal expansion differences between gear components and maintaining consistent backlash across the operating temperature range
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 consistent low circumferential backlash across a wide temperature range, preventing jamming and noise, while allowing for smooth and quiet engagement by adapting to temperature changes through the increased deformability of second teeth.
Implementation Method 1
If one toothed gear is comprised of a synthetic material and the other toothed gear of a metal or if the thermal expansion coefficients of the discrete components of a gearing have a marked difference, at the toothing engagement a considerable difference of the obtaining radial-/circumferential backlash will be present with a temperature change
Implementation Method 2
Due to their increased deformability, the second teeth act like a spring element with a second spring rate which is less than the first spring rate of the first teeth
Data Source
AI summary
A toothed gear for use in a gearing, comprising a base body that forms a ring gear with a number of first teeth having a first deformability and a number of second teeth having a second deformability, wherein the second deformability is greater than the first deformability and to a gear pair of a gearing, comprising such a toothed gear and at least one further toothed gear which can be made to mesh or is in mesh with the toothed gear. The invention relates moreover to a gearing with such a gear pair.