Gear Backlash Control via Adhesive Spacer Sheets

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Solution Overview

Problem

Existing methods for providing a predetermined backlash in gear transmissions using spacer means are difficult and expensive due to the complexity of applying coatings to gear teeth, requiring elaborate alignment equipment and additional steps.

Innovation Solution

A method involving gluing a sheet of spacer material to the upright sidewall of a toothed gear, which simplifies the application and control of backlash, allowing for precise positioning without the need for additional steps or removal of the spacer material, using compressible and rigid materials like polypropylene or metal foils with pressure-sensitive adhesives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a coating is applied to the upright sidewalls of gear teeth to provide backlash, then the backlash can be provided, but the application process becomes difficult and expensive requiring elaborate alignment equipment

Engineering Contradiction:
Improvebacklash precisionVSAvoidalignment equipment complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention divides the continuous coating approach into discrete spacer elements (shims or strips) that can be individually positioned and secured between the gear tooth and the mating gear. This segmentation allows for simpler application without requiring elaborate alignment equipment, as each spacer element can be independently positioned to achieve the desired backlash.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary spacer element that mediates between the gear tooth and the mating gear to establish the correct backlash. This intermediary component (spacer strip or shim) serves as a physical mediator that defines the clearance, eliminating the need for complex alignment equipment while maintaining precise backlash control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If a coating is used as spacer means, then backlash can be provided, but the thickness control becomes difficult and expensive

Engineering Contradiction:
Improvebacklash thickness controlVSAvoidcoating application ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention employs disposable or replaceable spacer elements (shims or strips) with predetermined thicknesses that can be easily manufactured and applied. These spacer elements are simple, inexpensive components whose thickness can be precisely controlled during manufacturing, making thickness control much easier and more cost-effective compared to applying controlled-thickness coatings.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the parameter of spacer material from a continuous coating with variable thickness control to discrete elements with fixed, predetermined thicknesses. This parameter change makes thickness control straightforward, as the backlash thickness is determined by the selected spacer element rather than requiring precise control of a coating application process.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If spacer material is used to provide backlash, then positioning can be achieved, but the spacer material may be displaced during operation

Engineering Contradiction:
Improvegear positioning precisionVSAvoidspacer material position stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention applies adhesive to the spacer element or gear tooth surface in advance of assembly, creating a preliminary bonding action that secures the spacer in its correct position. This preliminary adhesive action prevents displacement during operation, maintaining both the precise positioning and the reliability of the backlash clearance throughout gear operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces purely mechanical positioning methods (which rely on friction or interference fits that may allow displacement) with an adhesive bonding system. This substitution of mechanical retention with chemical adhesion provides more reliable position stability, preventing spacer material displacement while maintaining the precise gear positioning required for correct backlash.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method enables easier, faster, and more precise application of backlash, reducing the risk of spacer material displacement and maintaining operational integrity by using compressible yet rigid materials that remain on the gear during operation.

Implementation Method 1

The application of the spacer means comprises the step of gluing a surface of a sheet of spacer material to the upright sidewall of the first tooth

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP2171314B1Method of providing a predetermined backlash for a transmission, a first toothed gear and a method for applying a sheet of spacer material to at least part of an upright sidewall of a first toothed gear
Publication Date: 2013.01.02 VCST IND PROD
  • EP2171314B1 patent drawingFigure 1~3
  • EP2171314B1 patent drawingFigure 4

AI summary

A method of providing a predetermined backlash (4) for a transmission comprising at least a first (1 ) and a second (2) interlocking toothed gear, the backlash (4) being provided by positioning the first (1 ) and second (2) gear with respect to each other by means of spacer means (5) applied to at least part of an upright sidewall (3) of at least one first tooth (1 1 ), the upright sidewall (3) facing a second tooth (12) of the second gear (2) adjacent to the first tooth (11 ), characterized in that the application of the spacer means (5) comprises the step of gluing a surface (8) of a sheet (6) of spacer material to the upright sidewall (3) of the first tooth (11 ).