The invention relates generally to a magnetic brake, and particularly a linear eddy-current brake for rail vehicles.
Increased attention is being paid to eddy-current brakes, particularly within the scope of the further development of high-speed trains. The reason is that, since these eddy-current brakes do not contact the rail when braking, they do not wear out and can therefore be maintained at reasonable cost. A short introduction into the technology of eddy-current brakes for rail vehicles--whose function is based on the law of induction--is found, for example, in the book by Saumweber, et al "AET--Archiv fur Eisenbahntechnik" ("Archive for Railroad Technology"), Hestra Publishers, Volume 43, Chapter 2.5.2". Accordingly, eddy-current brakes consist of an iron yoke with several pole cores. Electric coils magnetically excite the brake such that magnetic north and south poles are formed in an alternating manner. When the excited eddy-current brake is moved over the rail--that is, when braking --, magnetic fields are formed which are caused by eddy currents and which result in the braking force.
The invention is aimed at improving the construction of eddy-current brakes.
The invention achieves this goal by providing a magnetic brake, particularly a linear eddy-current brake for rail vehicles, which has a magnet yoke extending almost along the whole length of the eddy-current brake and which, in the installed position, has a concave exterior shape at least toward the rail.
The invention is based on the recognition that the application forces generated during the operation of an eddy-current brake may lead to an elastic bending of the brake (see FIG. 4). Furthermore, the rail may bend because of the normal forces of the axles (see FIG. 5; for example, in the shunt area). In addition, the rail may, under certain circumstances, be raised slightly in the area of the shunts as a result of the attraction force of the magnets.
The above-described effects have the result that the air gap between the rail and the brake is not constant along the total length of the brake. When the air gap is adjusted, the minimal value in the center of the brake must be taken into account.
The invention remedies this effect in that the concave shaping results in a compensation of the bending in the sense of an at least largely uniform linear course of the air gap.
Advantageous further developments of the invention are found herein.
In the following, the invention will be explained in detail with reference to the drawing, in which case additional advantages of the invention are also illustrated.