Helical Gear Backlash Elimination via Elastic Biasing

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Solution Overview

Problem

In multi-color printers, the backlash between helical gears reduces rotational accuracy of plate cylinders, leading to deteriorated printing quality due to tilting and uneven contact between gears.

Innovation Solution

A plate cylinder drive unit design that allows rotational position adjustment of the driven gear member relative to the drive shaft, with a whirl-stop member fixation mechanism and elastic biasing to eliminate backlash, ensuring precise alignment and contact between helical gears.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a second driven gear is stacked with the first driven gear to eliminate backlash, then backlash between gears is reduced, but the driven gear member tilts and rotational accuracy deteriorates

Engineering Contradiction:
Improvebacklash eliminationVSAvoidrotational accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

A guide bar is introduced as an intermediary component to support the second driven gear. The guide bar prevents the second driven gear from tilting while maintaining axial clearance for backlash elimination, thus resolving the contradiction between backlash reduction and rotational accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The problem is solved by moving from a two-dimensional gear stacking approach to a three-dimensional solution involving axial clearance and radial guidance. The guide bar provides radial support while allowing axial movement, creating a spatial solution that addresses both backlash and tilting issues

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If axial clearance is formed between driven gears to ensure pressure contact, then gear meshing reliability is improved, but the structure complexity increases

Engineering Contradiction:
Improvegear meshing reliabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring mechanism automatically maintains the axial clearance and pressure contact between gears. The elastic force of the spring self-adjusts to keep the gears in proper meshing contact without requiring complex external control systems, thus improving reliability while limiting complexity increase

Inventive Principle:
Principle #25Self-service

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 solution eliminates backlash between drive and driven helical gears, enhancing rotational accuracy and printing quality by maintaining gear alignment and preventing tilting, resulting in improved printing performance.

Implementation Method 1

the backlash eliminating helical gear rotates in a predetermined direction with respect to the driven helical gear in a state in which the second elastic member biases the backlash eliminating helical gear

Methodology Applied
Scientific EffectElastic biasing: Elasticity

Implementation Method 2

helix angle of the both helical gears causes the driven helical gear to rotate with respect to the drive helical gear

Methodology Applied
Scientific EffectHelical gear meshing: Gear

Data Source

PatentEP2676796B1Plate cylinder drive device in printing machine
Publication Date: 2017.11.08 I MAR PLANNING INC
  • EP2676796B1 patent drawingFigure 1
  • EP2676796B1 patent drawingFigure 2
  • EP2676796B1 patent drawingFigure 3

AI summary

The present invention eliminates backlash between a drive helical gear and a driven helical gear and facilitates rotation of a driven gear member to increase rotational accuracy of a plate cylinder. A plate cylinder drive unit 3 includes a plate cylinder drive shaft 5, a driven gear member 7 having a driven helical gear 6 that meshes with a drive helical gear 1 and attached around the plate cylinder drive shaft 5, a position adjustment member 11 moving the driven gear member 7 to fix it at a predetermined position, a whirl-stop member 9 attached to the plate cylinder drive shaft 5, a sandwiching member 10 removably fixing the whirl-stop member 9 to the driven gear member 7, a backlash eliminating helical gear 8 disposed on one side of the driven helical gear 6, first springs 44 bringing the backlash eliminating helical gear 8 in pressure-contact with the driven helical gear 6, and second springs 46 biasing the backlash eliminating helical gear 8 to rotate it in a predetermined direction.