KTR designs couplings for rail industry

Edited by the Engineeringtalk editorial team Dec 2, 2008

KTR has designed a range of shaft couplings that have been specifically manufactured to meet the exacting specifications of the rail industry.

These include a membrane coupling and an overload system that significantly increase the service life of gear splines.

The company said that integrating the torsionally flexible Rotex coupling into a electromechanical drive system offers benefits to train manufacturers, maintenance staff, train drive design engineers and passengers.

The Rotex spider element can compensate for shaft misalignment and increases the service life of the drive system, while the damping characteristics of the spider aid the driving comfort of the vehicle.

The curved-tooth spline is made from a material that KTR has developed for applications in train technology allowing the service life of the coupling to exceed one million kilometers.

KTR's overload system makes use of the operating principle of a safety clutch and provides a consistent torque curve.

As soon as the overload torque (set by the manufacturer) is achieved, the power flow is interrupted - without any peak in the torque curve.

A high repeating accuracy is guaranteed, which is crucial for train drives.

The same applies when multiple overload instances occur.

Tests in the field have shown that overload systems on train drives can be activated up to 50 times a year.

This is not a problem for the Ruflex system.

KTR has also developed a type of friction lining that is resistant to wear and effective in protecting against the impact of environmental influences.

If requested, this coupling system may be equipped with sensor disks allowing for electronic control of twisting angles and as a result a reliable 'condition monitor' is achieved.

Rotex shaft couplings along with the Ruflex overload system are already used on the drive system of diesel-electric locomotives.

The combination of coupling and overload system is characterised by a low-cost plug-in assembly with a closed housing and short mounting dimensions.

The torsionally-rigid membrane coupling Radex MK is used in many railway applications.

KTR provides design engineers with a solution for the integration of compact single-bearing motors into the drive system.

Manufacturers of rail vehicles are often faced with a problem in this area.

On one hand the drives become more and more powerful, while on the other hand the mounting space available becomes more and more compact.

In order to achieve more compact dimensions single-bearing designs are used.

A torsionally-rigid coupling is used to transmit the power on the bearing of the rotor to the bearing of the first gearbox step.

On this critical application Radex MK is suitable because of its flexibility and its accuracy in production, thus achieving the precondition required for a smooth running of the power train.

This coupling may also be combined with a Ruflex overload unit that protects the drive train against torque shocks.

KTR said that its couplings have a proven track record in train technology, offering improved passenger comfort, longer service life of drive components and ease of assembly.