Axtone offers Crash components for High Speed Rail, providing passive protection of the vehicle in accordance with European standard EN 15227. The components are designed to cater for Customer's individual needs. They are characterized by excellent performance parameters resulting from the application of peeling technology.
The following products illustrate just some of the possible solutions.
In high-speed trains coil springs are used as primary and in some applications also as secondary suspension. Due to space and load requirements regarding the primary springs, linear spring sets are usually used.
Linear coil spring means a cylindrical coil spring with constant diameter and constant wire diameter. The spring ends are either “closed and ground” or “taper rolled, closed and ground”.
Spring set means that two linear coil springs with the same length are put together one into the other. Therefore the inner spring has a smaller outer diameter than the inner diameter of the outer spring. The inner spring also has a smaller wire diameter. The two springs of one set must have different coiling directions (one left, one right hand coiled).
If coil springs are also used in the secondary suspension, single linear coil springs are usually installed. As the lateral deflections are quite high, these springs must have a bigger length than primary springs.
The direction of the lateral displacement under vertical load (“chasse”) is marked on the springs and they have to be mounted into the vehicle according to the correct orientation of this marking.
As the strain (load amplitudes and their frequency) of the springs is also depending on the speed of the train, the springs for high-speed trains require a very high material grade and production quality.
Production of rings used for friction springs which meet the requirements of the chart UIC 827-2 takes place in the Czech company owned by the Group. The springs are manufactured in a wide range of various diameters from 80 to 400 mm. The rings are used in friction springs of Ringfeder type applied in buffers, tractive apparatuses, pull rod bars and automatic couplers.
Features:
- Hot formed, highest quality materials;
- Various shapes possible;
- Linear characteristic;
- Safe against overloading;
- Big damping due to friction;
- Characteristic independent of the speed;
- Characteristic independent of the temperature;
- Proven in rail applications.
Basic technical dates of friction springs:
| F Spring terminal force Se Stroke for 1 element We Spring work for 1 element he Height of 1 element | d1 Inner diameter b/2 Half ring width D2 Guide outer diameter d2 Guide inner diameter |
Example of spring calculation
This spring consists of 4 elements type 19600:
- End force = 600 kN
- Stroke = 4 x 4,4 (Se ) = 17,6 mm
- Spring work (Absorbed energy) = 4 x 1300 (We) = 5200 J
- Spring length = 4 x 23,4 (he) = 93,6 mm
By adding additional elements, we increase the stroke (length of the spring), the absorbed energy (spring work) but the end force will remain the same. End force still 600 kN.
During the operation of the friction spring two thirds of the input energy is dissipated as frictional heat. The recoil force at any point on the diagram is approximately equal 1 / 3 of the relative compressive force F. The capacity of the spring is represented by the total area shown below the load curve.
Friction springs are generally designed to „block”, so it is therefore ensured that the admissible stresses cannot be exceeded and the friction spring will not be damaged.
Applications:
- Buffers;
- Draw gears;
- Draw bars;
- (Semi) automatic couplers