Gear Transmission Flank Clearance Adjustment Mechanism

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Solution Overview

Problem

Existing clearance adjustment mechanisms for gearwheel transmissions are complex, costly, and difficult to use, with high material requirements, and do not provide accurate and efficient flank clearance adjustments, which can lead to increased radial forces, reduced bearing life, and noise issues in combustion engines.

Innovation Solution

A spigot with a threaded and conical portion is used to adjust the flank clearance by moving the gearwheel's centreline in parallel, allowing for precise adjustment with minimal material and manufacturing costs, using a conical step in the hole to cooperate with the spigot's conical portion, and a pivot pin for controlled movement, enabling accurate flank clearance adjustments with standard tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If known clearance adjustment mechanisms are used, then flank clearance can be adjusted, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveflank clearance adjustment accuracyVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The adjustment mechanism is segmented into distinct functional components: a spigot with threaded portion for axial positioning, a conical portion for radial adjustment, and a conical step for controlled movement. This segmentation allows each component to perform its specific function efficiently, reducing overall complexity while maintaining adjustment accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conical portion and conical step utilize curved surfaces to convert rotational movement into precise radial and axial adjustments. The conical geometry provides mechanical advantage and smooth, controlled movement of the gearwheel centreline, achieving accurate flank clearance adjustment without complex mechanisms.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Manufacturing precision

If complex adjustment mechanisms are used, then adjustment accuracy may improve, but ease of operation deteriorates

Engineering Contradiction:
Improveflank clearance adjustment accuracyVSAvoidadjustment ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The spigot's threaded portion engages with the gearwheel's threaded hole, allowing the spigot to self-position axially when rotated. The conical portion automatically centers on the conical step, providing self-aligning and self-adjusting functionality that simplifies operation while maintaining precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The conical surfaces provide automatic centering and guidance during adjustment. When the spigot is rotated, the conical portion rides on the conical step, automatically guiding the movement path and ensuring precise radial adjustment without requiring complex alignment procedures.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If more material is used in adjustment mechanisms, then reliability may improve, but quantity of substance and manufacturing cost increase

Engineering Contradiction:
Improvebearing service lifeVSAvoidmaterial requirement
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The mechanism uses minimal material concentrated in critical locations: the spigot with its threaded and conical portions, and the conical step in the gearwheel. This segmented approach provides reliable adjustment functionality with minimal material, reducing manufacturing cost while maintaining the reliability needed to protect bearing service life.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If conventional adjustment methods are used, then flank clearance can be modified, but radial forces and noise increase

Engineering Contradiction:
Improveflank clearance setting accuracyVSAvoidradial forces and noise
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The conical surfaces provide smooth, gradual adjustment of the gearwheel centreline, ensuring proper tooth engagement and minimizing impact loads. This results in reduced radial forces and noise while achieving the required flank clearance setting accuracy.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The adjustment mechanism allows dynamic modification of the centre distance between gearwheels, enabling optimal flank clearance to be achieved and maintained. This dynamic adjustment capability ensures proper tooth contact patterns, reducing radial forces and noise during operation.

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

The solution provides a simple, cost-effective, and accurate method for adjusting flank clearance, reducing radial forces and noise, while extending the service life of gearwheel bearings and ensuring precise transmission ratios, even under varying thermal conditions and manufacturing tolerances.

Implementation Method 1

A spigot (46) which comprises a threaded portion (48) that fits in a threaded aperture (54) in a frame element (30)

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

a conical portion (50) and is inserted in a hole (36) in the gearwheel, the hole has a conical step (52) configured to cooperate with the conical portion of the spigot

Methodology Applied
Scientific EffectConical friction mechanism: Conic Capillary Effect

Data Source

PatentEP3014146B1Method and device for adjusting the play of a gear transmission
Publication Date: 2019.11.06 SCANIA CV AB
  • EP3014146B1 patent drawingFigure 1
  • EP3014146B1 patent drawingFigure 2
  • EP3014146B1 patent drawingFigure 3

AI summary

The invention relates to a clearance adjustment mechanism (14) for a gearwheel transmission (12) which comprises at least one gearwheel (16, 66) with a centreline (39, 67), and a hole (36) formed in the gearwheel (16, 66) and running substantially parallel with the centreline (39, 67). A spigot (46) which is insertable in the hole (36), is provided with a threaded portion (48) and a conical portion (50) and fits in the hole (36) in such a way that the centreline (39, 67) moves in parallel when the spigot (46) is turned in the hole (36). The invention relates also to a gearwheel transmission (12) with such a clearance adjustment mechanism (14), to a combustion engine (4) with such a gearwheel transmission (12), to a vehicle (1) with such a combustion engine (4), and to a method for adjusting the flank clearance in such a gearwheel transmission (12).