Universal joint shafts are frequently used to transmit the power from a Diesel engine to the driven unit where the driven unit cannot be flange mounted to the engine.

Every Diesel engine produces torsional vibration and every universal joint shaft has a certain torsional elastic- ity. When these two components are connected to a driv- en machine a system is created which in many cases will generate very high vibratory torques somewhere within the equipment. In other words there will be a resonance speed. At this speed the equipment will be subject to very high alternating torques giving rise to noise and dam- age to working parts leading to premature failure of the system. In resonance the universal joint shaft acts like a spring, which is almost undamped and magnifies the tor- sional vibration produced by the engine. These oscillating torques can have a value of well over 10 times the output torque of the engine.

This problem can be solved by the introduction of a highly flexible intermediate coupling which will provide two advantages for the drive:

1) The torsional elasticity of the intermediate coupling and universal joint shaft combined is so high that the dangerous resonances are shifted below the operating speed of the engine.

2) The flexible intermediate coupling has a high damping capability so that the vibratory torque is reduced to an acceptable level only a short distance away from the resonance speed. Most importantly, the vibra- tory torque levels while passing through resonance on engine start up will be within acceptable levels.

The CENTAX series V intermediate couplings have all these desirable features.

The power flow normally goes from the engine flywheel through a flange to the highly flexible element and from there to the inner hub onto which the universal joint shaft is flange connected.

Driving and driven sides of the coupling are accurately located on a plain bearing so that good concentricity is provided. Additionally the rubber element is compressed in an axial direction. This preload is applied when the ele- ment is bolted to the inner hub and absorbed by an axial bearing. 

This axial preload has several advantages:

  • The adhesion of the rubber to the metal is enhanced.

  • The damping capacity of the rubber is increased.

  • When subjected to the high torsional vibration, with the drive side twisting relatively to the driven side, a relative movement occurs simultaneously on the axial plain bearing thus providing considerable friction dam- ping.

  • The coupling can absorb both tensile and compressive axial forces coming from the universal joint shaft. 

  • Advantages and characteristics

    • Linear stiffness characteristics.

    • Conservatively dimensioned flexible elements and bearings.

    • Internal ventilation of the couplings, hence good heat dissipation, the element will not overheat in normal operation.

    • The radial bearing is close to the universal joint, ensuring low angular moment.

    • Wide range of design and types, each size available with several standard SAE flywheel adaptors and hubs to suit a variety of universal shaft flanges.

    • Graduated torque range with each size having a vari- ety of torsional stiffness elements.

    • On request the couplings can be provided with clas- sification certificates.

    • Maximum angular misalignment of 9 degrees on uni- versal joint shaft.

    • The couplings are free of maintenance.

    • In addition to standard designs, other designs for special flywheels or universal joint shafts can be sup- plied.

    • Economical prices and ready availability.

      Important areas of application Construction equipment:

      between Diesel engine and hydrodynamic transmission, change speed gear and splitter gear, e.g. for dumpers, graders, scrapers, excavators, cranes, etc.

      Ship propulsion drives:

      between Diesel engine and marine gear, waterjet, stern- drive, Z or V drive.


      between engine and transmission, transmission and axle, engine and cooling pump.

      Pumping sets.