Preloaded Toothed Disc Gear Assembly for Backlash-Free Meshing

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Solution Overview

Problem

Existing backlash-free gear designs suffer from axial offset and play due to tension between disks, leading to complications in manufacturing and control of gear teeth alignment, which results in backlash and reduced freedom from play.

Innovation Solution

The use of asymmetrically arranged involute toothing on toothed discs with a spring washer and connecting bolts creates a calculable preload, allowing for symmetrical, play-free tooth engagement and transfer of this preload to a central hub, ensuring continuous rolling without play between tooth flanks and counter gears.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring pin is used to achieve tension between disks, then backlash-free operation is improved, but axial offset and play between disks and hub are introduced

Engineering Contradiction:
Improvebacklash-free operationVSAvoidalignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs asymmetric spring elements with different stiffness characteristics on each side of the gear assembly. By creating an asymmetric preload distribution, the system compensates for axial offsets and prevents play between disks and hub while maintaining backlash-free tooth engagement. The asymmetric design allows the softer spring side to accommodate misalignment without creating gaps.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent modifies the mechanical parameters of the spring elements, specifically using softer spring constants on one side compared to the other. This parameter change enables the system to absorb axial deviations and maintain continuous tooth contact despite manufacturing tolerances and assembly variations, thereby preventing play while preserving backlash-free operation.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If symmetrical teeth are used in meshing gears, then manufacturing simplicity is improved, but play arises between meshing rows due to axis misalignment

Engineering Contradiction:
Improvegear manufacturing simplicityVSAvoidcontinuous rolling contact
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces asymmetric spring preloading to compensate for the inherent play in symmetrical gear meshes. By creating differential preload forces, the system ensures continuous contact on the driving side while allowing controlled clearance on the non-driving side, thereby maintaining reliable rolling contact despite axis misalignment while keeping symmetrical tooth geometry.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies preliminary asymmetric preloading forces through the spring elements before the gear transmission begins operation. This preliminary action pre-compresses the tooth contacts in a controlled manner, preventing the development of play during operation and ensuring continuous rolling contact from the start of operation despite symmetrical tooth design and potential axis misalignment.

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If a toothed disc is shifted circumferentially in a fixture, then backlash-free pre-tensioning is achieved, but manufacturing complexity and backlash control difficulty increase

Engineering Contradiction:
Improvebacklash-free pre-tensioningVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables the toothed discs to self-adjust and self-preload through the asymmetric spring mechanism during normal operation. The springs automatically apply the necessary differential forces to maintain backlash-free engagement without requiring complex pre-adjustment fixtures or manual circumferential shifting operations, thereby simplifying the manufacturing process while maintaining reliable pre-tensioning.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent transitions from a static, pre-adjusted backlash-free system to a dynamic system where asymmetric springs continuously adapt the preload forces based on operating conditions. This dynamic approach maintains backlash-free engagement automatically during operation, eliminating the need for complex static pre-adjustment procedures and reducing manufacturing complexity.

Inventive Principle:
Principle #15Dynamics

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

This solution provides a backlash-free gearing system with enhanced load-bearing capacity, reduced idling friction, and improved rigidity, eliminating the need for additional position measurement systems and allowing for cost-effective production across various applications.

Implementation Method 1

a spring disc with a toothless smooth outer circumference is arranged axially parallel to the axis on one side of a circular surface and below the asymmetrical involute toothing of the toothed disc, with openings, including several spaced-apart spirally extending spring surfaces

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

which is positively connected to each toothed disc via connecting bolts

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3985283A1Play-free toothing
Publication Date: 2022.04.20 BREHM BERNHARD
  • EP3985283A1 patent drawingFigure 1~2
  • EP3985283A1 patent drawingFigure 3~4
  • EP3985283A1 patent drawingFigure 5~6

AI summary

The invention relates to a backlash-free gear for drives of systems in a wide variety of technical fields. The objective was to find a backlash-free gear that ensures radially and backlash-free pre-tensioned toothed discs are mounted on a hub, transmit power to a mating gear, and guarantee uninterrupted rolling of the tooth flanks of the toothed discs against the tooth flanks of the mating gear.The invention is characterized by a toothed disc which has an asymmetric involute toothing on its outer circumference and is positively connected on one side and below the toothing to a spring disc with a toothless outer circumference and radial spiral spring surfaces, and in that a second toothed disc with a spring disc of the type described above is arranged opposite to the direction of rotation, with which a toothed disc pair with mutually directed radial preload and a backlash-free, symmetrical involute toothing on the outer circumference is to be formed and by continuous arrangement of further such toothed disc pairs, always opposite to the direction of rotation, are to be firmly connected as a toothed roller via a central opening on a central hub.