Today's high-speed trains can travel at more than 300 km/h. Just imagine the forces at play in the form of air resistance and wear and tear. The carriage door systems must function flawlessly under such extreme conditions. This is why we have developed cold-formed threaded spindles made of aluminium, which ensure that the doors can be opened and closed safely in any situation, even after many years and thousands of kilometres on the rails.
Aluminium leadscrews deliver reliability
The forces acting at high speeds are exceedingly imposing: for example, air resistance increases in square of the speed. This means that if speed doubles, air resistance quadruples. The same applies to door systems. The linear drive is at the heart of these door systems. The goal of our designers was to develop a more cost-effective solution for the motional tasks inside this drive unit:
In the tightest of spaces
The linear drives have to operate in the tightest of spaces, guaranteeing great force, robustness, precision and reliability. The doors need to move easily and quickly. The spindle-nut system must not self-lock in the event of a power failure as manual opening of the doors must be possible at any time.
Key innovations are always the result of intensive development work. The cold-rolled aluminium leadscrew type EASY with a special 20 mm profile diameter and 80 mm pitch was the result of such efforts.
EASY aluminium high helix spindle: cold-formed, hard-anodised
Only when the various components - such as the right raw and alloy material, impeccable cold forming with thread rolling tools specially produced by Eichenberger for the rolling process - are in perfect alignment can the optimum material flow for a high 80 mm pitch ratio be achieved. Eichenberger is able to offer development, production and quality assurance simultaneously. This gives a high level of technical flexibility in the manufacturing process or in the creation of prototypes, including thread rolling tools. A high degree of know-how is also essential when it comes to the design of the tools for the internal thread of the plastic screw nut.
The combination of the special hard-anodised aluminium 20 / 80 high-helix threaded spindle and the plastic nut (nut material varies according to the application) is designed in such a way that the spindle can be manufactured by cold forming. This thread rolling process brings considerable advantages in terms of hardening, rough surface values and notch sensitivity. The special profile of the thread gives a totally different load-bearing effect. The tilting moment is absorbed by the outer diameter of the spindle, which ensures smooth operation and prevents jamming.
Sliding screw drive EASY 20 x 80
Aluminium is lightweight while retaining high stability and load-bearing capacity
Plus points at a glance
The aluminium threads, already massively reinforced by thread rolling, become even more resistant through further refinement of the outer layer, or hard anodising. This reduces the friction coefficient and results in very good sliding properties. These values and of course the protection against corrosion are instrumental in ensuring a long service life.
What sounds simple can only be achieved with a wealth of experience gained over many decades, a high level of quality awareness and modern machinery. The dynamic ratio of 80 mm pitch and 20 mm diameter facilitates a very high traversing speed. A single-thread standard trapezoidal 20 mm diameter spindle would have to rotate over 16 times faster to achieve such a high nut speed. In addition, the low speeds favourably impact on wear and noise.
The streamlined and fast production of large quantities positively affects the price. Non-standard thread forms are the challenges we are looking for. On request, Eichenberger can also produce tailor-made and solution-oriented diameters and pitches for aluminium spindles.
Speedy aluminium leadscrew ø 26 mm, pitch 6 mm