Off-Center Thrust Washer for Play-Free Eccentric Shaft Connection

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Solution Overview

Problem

Existing transmission systems face challenges in securely connecting axial components without rotational play, particularly in non-circular shaft-hub connections, which complicates the manufacturing process and torque transmission.

Innovation Solution

A transmission design featuring an off-center circular recess on a thrust washer with an axially protruding projection that secures the washer non-rotatably to an eccentric shaft, utilizing an eccentric core area and involute toothing for stable, backlash-free connections, allowing for high torque transmission in a compact space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional shaft-hub connection is used to secure the thrust washer to the eccentric shaft, then the connection can be achieved, but rotational play occurs and the connection becomes complex

Engineering Contradiction:
Improveconnection stabilityVSAvoidconnection structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by providing an off-center circular recess in the thrust washer that receives an axially projecting section of the eccentric shaft. This asymmetric arrangement creates a non-rotatable connection without requiring complex additional components, as the offset geometry inherently prevents rotation while maintaining simplicity

Inventive Principle:
Principle #4Asymmetry

2Power

If a non-circular shaft-hub connection is used for the planetary gear, then high torque can be transmitted, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvetorque transmissionVSAvoidmanufacturing process
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent employs a non-circular (polygonal) shaft-hub connection between the planetary gear and eccentric shaft to transmit high torque. The asymmetric geometry provides multiple engagement surfaces that increase torque capacity while the design integrates this feature into the existing eccentric shaft structure, balancing manufacturing feasibility with power transmission requirements

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3322908B1Gearing with thrust washer for axially securing rolling bodies of a bearing
Publication Date: 2021.03.17 SEW EURODRIVE GMBH & CO KG
  • EP3322908B1 patent drawingFigure 1
  • EP3322908B1 patent drawingFigure 2
  • EP3322908B1 patent drawingFigure 3

AI summary

Thrust washer for axially securing rolling bodies of a bearing and gearing with the thrust washer, wherein the thrust washer is designed as a circular disc, which has an axially protruding projection, in particular an axially outer projection, wherein the circular disc has a clearance, which is arranged off-centre, in particular wherein the centre point of the preferably circular clearance is therefore at a distance from the centre axis and/or from the centre point of the circular disc, in particular wherein the projection is of a ring-shaped form and the axis of the ring is at a distance from the centre point of the preferably circular clearance.