Circular Arc Gear Profiles for High Torque Transmission

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Solution Overview

Problem

Existing gear transmissions face challenges in achieving high torque transmission with a compact design while maintaining low noise and minimizing wear, as conventional involute gearing has limitations in flank load capacity and precision.

Innovation Solution

The development of a transmission with circular arc tooth profiles and S-shaped cutting edges, where the radius of curvature is maintained with high precision, and the gear design includes helical or spur teeth with a convex-convex or convex-concave engagement, ensuring high flank load-bearing capacity and reduced wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional involute gearing is used, then the gearbox structure is simple and easy to manufacture, but the flank load-carrying capacity is limited and torque transmission is reduced

Engineering Contradiction:
Improveflank load-carrying capacityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies circular arc tooth profiles instead of conventional involute profiles. The circular arc shape with optimized radius of curvature creates more favorable contact conditions between mating gears, distributing loads more effectively across the tooth flanks. This curved geometry increases flank load-carrying capacity while maintaining manufacturability through specialized cutting tools designed to produce the circular arc profiles.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Strength

If the radius of curvature of the circular arc is increased, then the flank load-bearing capacity is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveflank load-bearing capacityVSAvoidradius of curvature precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent optimizes the radius of curvature parameter of the circular arc profile to achieve an optimal balance between load-bearing capacity and manufacturability. By carefully selecting and standardizing specific radius values, the design ensures high flank load capacity while keeping manufacturing precision requirements within achievable limits using conventional machining equipment and processes.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the active engagement area is maintained undisturbed, then the torque transmission efficiency is improved, but the ability to correct manufacturing deviations is reduced

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidprofile correction capability
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent applies different profile characteristics to different regions of the tooth flank. The active engagement area maintains an undisturbed circular arc shape optimized for torque transmission, while the root and tip areas allow for corrections to reduce entry and exit shocks. This localized differentiation ensures both efficient torque transmission and acceptable manufacturing tolerances.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3380756B1Method of manufacture of a gearbox having a first gearwheel and a second gearwheel
Publication Date: 2020.09.02 SEW EURODRIVE GMBH & CO KG
  • EP3380756B1 patent drawingFigure 1
  • EP3380756B1 patent drawingFigure 2
  • EP3380756B1 patent drawingFigure 3

AI summary

A gearbox having a first gearwheel, which is rotatable about a first axis of rotation, and having a second gearwheel, which is rotatable about a second axis of rotation, wherein the first and the second axis of rotation are oriented parallel to one another and are spaced apart from one another, wherein the first gearwheel, in particular spur gear, is formed with teeth which are spaced apart from one another uniformly in a circumferential direction and which are in particular in each case of identical design, wherein, in particular in cross section, one of the two flanks of the respective tooth is in the form of a circular arc at least in the active engagement region, wherein in particular, the axes of rotation are parallel to a normal to the section plane of the cross section, wherein the central point of the circle that comprises the circular arc has a finite and non-insignificant spacing to the first and to the second axis of rotation, that is to say in particular an eccentric offset e, and in that the central point of the circle that comprises a circular arc has a finite and non-insignificant spacing to the plane that encompasses the first and the second axis of rotation, that is to say in particular a lateral offset I.