Non-Circular Coupling Profile for Torque Transfer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional conic couplings rely heavily on friction for torque transfer, leading to weight, complexity, and cost issues, making them less suitable for weight-critical applications and more difficult to assemble.

Innovation Solution

A coupling with a non-circular connection profile defined by a varying annular projection and recess, allowing for increased torque capacity without added weight or complexity, featuring optional elliptical, square, hexagonal, or octagonal profiles that simplify alignment and assembly, and include angled side surfaces for improved contact and robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional conic couplings use friction-based torque transfer, then torque transfer capability is achieved, but weight and device complexity increase

Engineering Contradiction:
Improvetorque transfer capabilityVSAvoidcoupling structure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by using a non-circular connection profile (such as rectangular, oval, or irregular shape) instead of a conventional circular profile. This asymmetric geometry creates interlocking surfaces between the first and second elements that directly transmit torque through mechanical engagement rather than relying on friction. The non-circular profile ensures positive engagement while reducing the need for additional alignment features or fasteners, thereby reducing device complexity while maintaining torque transfer capability

Inventive Principle:
Principle #4Asymmetry

2Strength

If conventional conic couplings use multiple fasteners, then connection strength is improved, but assembly difficulty and time increase

Engineering Contradiction:
Improveconnection strengthVSAvoidassembly ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent merges the functions of multiple fasteners into a single integrated non-circular connection profile. The interlocking geometry of the asymmetric profile provides both mechanical strength and alignment functionality that would otherwise require separate fasteners and alignment features. This consolidation maintains connection strength while significantly simplifying assembly, as the non-circular profile naturally guides alignment and requires only a single fastening operation rather than multiple bolt holes and fasteners

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The non-circular connection profile uses asymmetric geometry to provide inherent alignment features that eliminate the need for multiple fasteners. The unique shape ensures that only one orientation fits properly, providing self-alignment during assembly. This asymmetric design maintains strong mechanical engagement while reducing assembly complexity and time, as the profile itself serves as both the connection mechanism and the alignment guide

Inventive Principle:
Principle #4Asymmetry

3Ease of manufacture

If conventional couplings use circular connection profiles, then manufacturing is simpler, but torque capacity and alignment precision decrease

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidtorque capacity
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The patent transitions from a circular symmetric profile to a non-circular asymmetric profile. While the asymmetric shape requires slightly more complex manufacturing, modern machining and forming processes can easily produce these profiles. The payoff is significant: the non-circular geometry provides positive mechanical engagement for torque transfer, inherent alignment features, and improved torque capacity compared to circular profiles that rely on friction. The manufacturing complexity increase is minimal compared to the substantial performance gains

Inventive Principle:
Principle #4Asymmetry

4Power

If conventional conic couplings rely on friction, then torque transfer is achieved, but weight increases

Engineering Contradiction:
Improvetorque transfer capabilityVSAvoidcoupling weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The non-circular connection profile uses asymmetric interlocking geometry to transmit torque directly through mechanical engagement rather than through friction. This eliminates the need for large contact surfaces and high normal forces that would require heavier components. The asymmetric profile provides sufficient torque capacity with lighter materials and thinner sections, directly reducing the weight of the coupling while maintaining the required power transmission capability

Inventive Principle:
Principle #4Asymmetry

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 non-circular connection profile enhances torque carrying capacity, reduces the need for fasteners, and simplifies assembly by providing multiple orientation options and improved resistance to imperfections, making the coupling more efficient and user-friendly.

Implementation Method 1

the annular projection being removably accommodated within the annular recess, and wherein a radius of the annular projection varies circumferentially around the axis to thereby define a connection profile

Methodology Applied
Scientific EffectMechanical engagement:

Implementation Method 2

Rotation of the male or female element is transmitted to the other element by friction between the abutting side surfaces

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2840273B1Coupling
Publication Date: 2018.01.17 ROLLS ROYCE PLC
  • EP2840273B1 patent drawingFigure 1~2
  • EP2840273B1 patent drawingFigure 3
  • EP2840273B1 patent drawingFigure 4

AI summary

A coupling (200) includes a first element (210) having an annular projection (210) and a second element (240) having an annular recess (250). Both the first element (210) and the second element (240) have a common axis (205). A radius of the annular projection (210) varies circumferentially around the axis (205) to thereby define a connection profile (270). The annular projection (210) is removably accommodated within the annular recess (250) to couple the first (210) and second (240) elements to one another.