Gear Flexible Coupling Axial Travel Limiting Inversion

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Solution Overview

Problem

Existing gear flexible couplings used in high-speed trains are limited by their size, torque transmission capacity, and sealing efficiency, requiring frequent servicing due to axial and angular misalignments.

Innovation Solution

The axial travel limiting device is reconfigured with the nose fixed to the sleeve and abutment elements to the hub, enhancing the structural rigidity and stiffness of the hub, allowing higher torque transmission and improved sealing through a more effective stop function and reduced deformation, while maintaining axial and angular misalignment capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the axial travel limiting device is configured with the nose fixed to the hub and abutment elements fixed to the sleeve (prior art), then the device can limit axial relative movements, but the hub requires a larger annular section which reduces structural rigidity and torque transmission capacity

Engineering Contradiction:
Improvetorque transmission capacityVSAvoidhub annular section configuration
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent inverts the prior art configuration by fixing the nose to the sleeve instead of the hub, and fixing the abutment elements to the hub instead of the sleeve. This inversion allows the hub to have a smaller, more rigid annular section while the sleeve absorbs the axial limiting function, thereby improving torque transmission capacity without compromising axial movement limitation.

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

2Strength

If the hub annular section is reduced to improve structural rigidity, then torque transmission capacity increases, but the sealing effectiveness may be compromised due to reduced space for seal members

Engineering Contradiction:
Improvestructural rigidityVSAvoidsealing effectiveness
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By inverting the axial limiting device configuration, the sealing surface is transferred from the hub to the sleeve (specifically to the cap fixed to the sleeve). This allows the hub annular section to be minimized for maximum rigidity, while the sleeve provides adequate space and surface area for effective seal members, thus maintaining both structural rigidity and sealing reliability.

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

3Volume of moving object

If the gear coupling is designed for compact size, then space requirements are reduced, but the torque transmission capacity and ability to handle dynamic angular misalignments are limited

Engineering Contradiction:
Improvegear coupling sizeVSAvoidtorque transmission capacity
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The inverted configuration of the axial travel limiting device enables a more efficient use of the hub annular section, which can be minimized without compromising strength. This inversion allows the compact design to maintain adequate torque transmission capacity by concentrating the structural strength where most needed while the sleeve handles the axial limiting function.

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

Solution Approach 2:

The patent optimizes the geometric parameters of the hub and sleeve to achieve a compact overall size while maintaining sufficient torque transmission capacity. By changing the distribution of functional elements (inverting the axial limiting configuration), the design achieves better parameter efficiency, allowing compact dimensions without sacrificing strength.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If frequent servicing is required to maintain sealing effectiveness, then reliability is maintained, but operational efficiency and productivity decrease

Engineering Contradiction:
Improvesealing effectivenessVSAvoidservicing frequency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

By inverting the axial limiting device configuration and relocating the sealing interface to the sleeve rather than the hub, the patent creates a more reliable sealing arrangement that is less prone to degradation. The sleeve provides a more stable sealing surface that maintains effectiveness over longer periods, thereby reducing servicing frequency and improving operational productivity while maintaining reliability.

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

Data Source

PatentEP2492530B1Gear flexible coupling for transmitting torque between a drive shaft and a driven shaft, particularly for use on high-speed trains
Publication Date: 2014.05.14 MAINA ORGANI DI TRASMISSIONE
  • EP2492530B1 patent drawingFigure 1
  • EP2492530B1 patent drawingFigure 2
  • EP2492530B1 patent drawingFigure 3

AI summary

The gear coupling (10; 110) comprises first and second half-couplings (12, 12'; 112, 112'), each comprising a hub (14, 14'; 114, 114') provided with rounded outer teeth (36, 36'; 136, 136') and a sleeve (16, 16'; 116, 116') provided with inner teeth (40, 40'; 140, 140') meshing with the outer teeth (36, 36'; 136, 136'). Each hub comprises a first radially inner tubular portion (26, 26'; 126, 126') and a second radially outer tubular portion (28, 28'; 128, 128'), which is arranged coaxially to the first one and on which the outer teeth (36, 36'; 136, 136') are provided. Each half-coupling further comprises a cap (44, 44'; 144, 144') which is fixed to the sleeve and comprises a tubular portion (48, 48'; 148, 148') extending in an annular seat (30, 30'; 130, 130') provided between the first and second tubular portions of the hub. At least one half-coupling further comprises an axial travel limiting device (52, 52'; 152, 152') which is accommodated in the annular seat of the hub and comprises a stop annular element (54, 54'; 154, 154') fixed to the tubular portion of the cap and a pair of abutment elements (56, 58, 56', 58'; 156, 158, 156', 158') which are fixed to the hub and are arranged on axially opposite sides with respect to the stop annular element so as to define respective axial abutment surfaces for this latter.