Torque Transmission Collar with Concave Tooth Flanks

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Solution Overview

Problem

Existing torque transmission systems face challenges in efficiently transmitting torque between components with concave and convex surfaces, leading to issues with disengagement and manufacturing complexity, particularly in axle assemblies where precise gear ratios and lubrication management are critical.

Innovation Solution

A torque transmission apparatus featuring a collar with concave side surfaces and a set of teeth that mate with convex surfaces on drive components, allowing axial movement while inhibiting rotation, thereby simplifying the manufacturing process and enhancing torque transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional tooth flank shapes are used in splined connections, then manufacturing complexity increases and disengagement becomes difficult, but torque transmission efficiency is maintained

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddisengagement performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent inverts the conventional tooth flank configuration by making the collar tooth flanks concave and the drive component tooth flanks convex, rather than the traditional convex-concave arrangement. This inversion simplifies manufacturing by eliminating the need for complex cutting tools while improving disengagement characteristics through the negative pressure angle geometry

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the geometric parameters of the tooth flanks by introducing concave surfaces with negative pressure angles. This parameter change transforms the engagement characteristics, allowing for easier disengagement and simplified manufacturing without compromising torque transmission capability

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If expensive cutting tools are used to create precise tooth profiles, then manufacturing precision improves, but manufacturing cost increases

Engineering Contradiction:
Improvetooth profile precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs simpler, less expensive cutting tools that can be used for creating the tooth profiles. The concave tooth flank geometry allows for using basic forming tools rather than expensive precision cutting tools, reducing manufacturing cost while maintaining adequate precision for torque transmission

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By changing the tooth flank geometry to concave surfaces with negative pressure angles, the patent enables the use of simpler manufacturing processes and tools, thereby reducing manufacturing precision requirements and associated costs while still achieving functional performance

Inventive Principle:
Principle #35Parameter changes

3Strength

If conventional tooth geometries with positive pressure angles are used, then structural strength is maintained, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvetooth structural strengthVSAvoidtooth geometry complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent inverts the conventional positive pressure angle geometry by using negative pressure angles on the collar tooth flanks. This inversion maintains structural strength through proper geometric design while significantly reducing the complexity of manufacturing and assembly operations

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces asymmetric concave surfaces on the collar tooth flanks with negative pressure angles, creating an asymmetric geometry that simplifies the mating convex surfaces on drive components. This asymmetric design maintains strength while reducing overall system complexity

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3578842B1Torque transmission apparatus and a collar having concave tooth side surfaces
Publication Date: 2020.12.30 ARVINMERITOR TECHNOLOGY LLC
  • EP3578842B1 patent drawingFigure 1
  • EP3578842B1 patent drawingFigure 2
  • EP3578842B1 patent drawingFigure 3

AI summary

A collar and a torque transmission apparatus having a collar. The collar may have a set of collar teeth. Each collar tooth may include a first end surface, a second end surface, a first collar side surface, and a second collar side surface. The first and second collar side surfaces may be concave from the first end surface to the second end surface.