Highly Flexible Couplings – Technical information

Driveline

Highly Flexible Coupling – Driveline

A driveline will normally consist of:

  • a driving machine (prime mover)
  • coupling elements (couplings, gears etc.)
  • a driven machine (power consumer)

The individual components of a driveline are made of elastic materials (e.g. steel) and have a mass. Accordingly they represent a system susceptible to torsional vibration. If this system is incited, it will start vibrating with a determined frequency: its natural frequency and amplitude.

If a damping is introduced, the vibration amplitude will assume a finite value. A reciprocating diesel engine does not convey its capacity evenly over one rotation of the crankshaft. Nonetheless, a diesel engine strains the driveline considerably, especially since the new injection technologies have been introduced and there is the trend towards ever lighter inertia weights.

A useful operational strength and unit lifetime is often achieved only after a highly flexible coupling has been installed in the driveline.

Design and properties of the highly flexible coupling

Torsional Coupling Design

The elastomer element is the basic functional and constructional component of Voith highly flexible couplings.

An essential characteristic feature of the elastomer element is its great capacity for deformation that is attained through the special molecular structure of the material and gives it an elastomeric-viscous quality.

When a elastomer element is deformed, the work of deformation is transformed to:

  • Elastic energy which can be reconverted to mechanical work (spring-back to the initial position).
  • Viscous energy which is dissipated in the form of heat.

Friction damper
To maximise damping, Voith highly flexible couplings can be equipped with an optional friction damper. This is a friction disk which is inserted between the primary and the secondary part of the coupling and is preloaded by the elastomer element. The required damping can be adjusted via the preload path of the element. The Kuesel universal joint shaft coupling with frictional damping is a development of the company "Küsel Drives".

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Functions of the highly flexible coupling

Torsional Coupling – Functions

In systems where a diesel engine acts as prime mover, the highly flexible coupling has mainly two functions:

  1. moving natural frequencies
  2. damping critical torsional vibration amplitudes

Voith highly flexible couplings are well-suited to these tasks:

  • Special elastomers are employed in the spring elements that feature both high elasticity and excellent damping characteristics.
  • The damping effect can be further increased using additional friction damping.
  • A suitable design and material selection allows us to vary the characteristic data of a coupling and to adapt them to the customer's specific requirements.

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Customer benefits of the highly flexible coupling

Customer benefit by using a Voith highly flexible coupling in the driveline:

  • increased availability of all components in the driveline
    due to damping of torsional vibrations and load peaks in the driveline
  • decreased life cycle costs
    due to increases lifetime of all driveline components
  • increased comfort
    due to less vibration and noise

Dimensioning of highly flexible couplings

Dimensioning a highly flexible coupling is an iterative process due to the complexity of the material stressing:

Torsional Coupling – Dimensioning