Toothed Belt Shear Strength Testing Under Dynamic Load

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Solution Overview

Problem

Existing methods for testing the shear strength of toothed belts under dynamic loading are inadequate as they do not simulate real operating conditions, leading to unrealistic load scenarios and failure modes that do not accurately represent service life behavior.

Innovation Solution

A method and device that dynamically load a toothed belt by stretching it around a freely rotating toothed pulley with a pulsating tensile force, simulating the belt's wrap around a pulley and measuring shear stress, allowing for realistic testing of tooth shearing strength over multiple load cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a toothed belt is tested under static loading conditions, then the test setup is simple and straightforward, but the test results do not correlate well with real service life behavior

Engineering Contradiction:
Improvecorrelation between test results and service life behaviorVSAvoidcomplexity of test setup
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from static loading to dynamic loading by rotating the toothed pulley at controlled speeds while applying pulsating tensile forces to the toothed belt. This dynamic testing approach simulates real operating conditions, improving the correlation between test results and actual service life behavior.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies periodic pulsating tensile forces to the toothed belt during rotation, creating cyclic loading conditions that mimic real-world operational patterns. This periodic action allows assessment of fatigue resistance and tooth shearing strength under realistic varying load conditions.

Inventive Principle:
Principle #19Periodic action

2Reliability

If a toothed belt is tested with high pressing force on the back, then the test can be performed on simple equipment, but the load on the test tooth is unrealistic and does not represent actual operating conditions

Engineering Contradiction:
Improverealism of load conditionsVSAvoidpressing force on belt back
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent changes the loading parameters by eliminating excessive pressing forces and instead applying controlled pulsating tensile forces during rotation. This parameter change creates realistic load conditions that accurately represent actual operating stresses on the toothed belt teeth.

Inventive Principle:
Principle #35Parameter changes

3Force

If a toothed belt is tested without simulating wrap around the pulley, then the test setup is simpler, but the test force required is significantly higher than expected in real operation

Engineering Contradiction:
Improvetest force requiredVSAvoidcomplexity of wrap simulation
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent preliminarily configures the test setup to include a toothed pulley and routing arrangement that pre-establishes the wrap angle and contact geometry before testing begins. This preliminary action ensures that the belt naturally wraps around the pulley during rotation, reducing the required test force to realistic operational levels.

Inventive Principle:
Principle #10Preliminary action

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 approach provides a better correlation between test conditions and real service life behavior, enabling the development of timing belts with improved tooth strength by accurately testing tooth shearing strength under realistic operating conditions and varying load levels.

Implementation Method 1

During the flow of forces between the teeth of the belt and the teeth of the belt pulley, strong shearing or shearing stresses arise in the connection of the toothed belt

Methodology Applied
Scientific EffectShear stress: Shear Stress

Implementation Method 2

toothed belts made of elastomeric material, preferably rubber

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2963407B1Method and device for testing the shear strength of the teeth of a toothed belt
Publication Date: 2017.07.12 CONTITECH ANTRIEBSSYSTEME GMBH
  • EP2963407B1 patent drawingFigure 1
  • EP2963407B1 patent drawingFigure 2
  • EP2963407B1 patent drawingFigure 3

AI summary

Method and apparatus for testing the wear resistance of teeth of a toothed belt under dynamic load, wherein the toothed belt is tensioned around a toothed pulley consisting of an inner drum and an outer toothed ring rotatably surrounding the drum, wherein the toothed belt is subjected to a pulsating tensile force by clamps attached to its ends, and wherein a tooth of the toothed belt is received in a recess of the toothed ring arranged within the wrap angle in a separate cam belonging to the drum, and the torque exerted by the tooth on the drum is supported and measured.