High-speed trains reach speeds of over 300 km/h. Imagine the forces involved in terms of air resistance and wear. The door systems of the carriages must function perfectly even under such stresses. We have therefore developed cold-formed threaded spindles made of aluminum, which allow the doors to open and close safely in any situation, even after many years and thousands and thousands of kilometers of track.
Aluminum screw drives ensure reliability
The forces acting at high speeds are more than impressive: Air resistance, for example, increases as the square of the speed. So if the speed doubles, the air resistance quadruples. This also applies to door systems. At the heart of these door systems is the linear drive. The aim of our design engineers was to develop a more cost-effective solution for the movement tasks inside these drive units:
In the tightest of spaces
The linear drives have to guarantee high force exertion, robustness, precision and reliability in the tightest of spaces. The doors should move easily and quickly. In the event of a power failure, the spindle-nut system must not be self-locking. Emergency opening must be possible by hand at all times.
Decisive innovations are always the result of intensive development work. We have succeeded in producing the EASY cold-rolled aluminum lead screw with a special profile diameter of 20 mm and a pitch of 80 mm.
EASY aluminium steep thread spindle: cold-formed, hard-anodized
The material flow for a high pitch ratio of 80 mm can only be optimized if the various components - such as the right raw material/alloy, flawless cold forming with thread rolling tools specially manufactured by Eichenberger for the rolling process - are in harmony. Eichenberger is able to offer development, production and quality assurance at the same time. This means that flexibility in the manufacturing process or in prototype production, including thread rolling tools, is at a high technical level. Potent know-how is also essential when it comes to designing the tools for the internal thread of the plastic nut.
The combination of the special hard-anodized aluminium 20 / 80 pitch threaded spindle and the plastic nut (nut material depending on the application) is designed in such a way that the spindle can be manufactured using the cold forming production process. The thread rolling process results in impressive advantages in terms of hardening, roughness values and notch sensitivity. The special profile of the thread provides a completely different support. The tilting moment is absorbed via the outer diameter of the spindle, which ensures smooth operation and prevents jamming.
Aluminum offers light weight with consistent stability and high load capacity
Plus points at a glance
The aluminum threads, which have already been solidified by the thread rolling process, are given a further outer layer finish, or hard anodizing, an even more resistant surface. This results in an additional reduction in friction and very good sliding properties. These values and, of course, the protection against corrosion, are the main reasons for 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 allows a very high traversing speed. To achieve such a high nut speed, a single-start standard trapezoidal spindle with a diameter of 20 mm would have to rotate over 16 times faster. In addition, the low speeds have a positive effect on wear and noise generation.
The efficient and fast production of large quantities has a positive effect on the price. For us, thread forms that are outside the norm are the challenges we are looking for. On request, Eichenberger can also realize customer and solution-oriented diameters and pitches for aluminium spindles.
