EP0042787A1 - Electromagnetic skid - Google Patents

Electromagnetic skid Download PDF

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Publication number
EP0042787A1
EP0042787A1 EP81400963A EP81400963A EP0042787A1 EP 0042787 A1 EP0042787 A1 EP 0042787A1 EP 81400963 A EP81400963 A EP 81400963A EP 81400963 A EP81400963 A EP 81400963A EP 0042787 A1 EP0042787 A1 EP 0042787A1
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EP
European Patent Office
Prior art keywords
rail
magnetic
friction
pad
electromagnetic
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EP81400963A
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German (de)
French (fr)
Inventor
André Willem Hendrickx
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Sa Wabco-Standard Nv
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Sa Wabco-Standard Nv
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Publication of EP0042787A1 publication Critical patent/EP0042787A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61H—BRAKES OR OTHER RETARDING DEVICES SPECIALLY ADAPTED FOR RAIL VEHICLES; ARRANGEMENT OR DISPOSITION THEREOF IN RAIL VEHICLES
    • B61H7/00—Brakes with braking members co-operating with the track
    • B61H7/02—Scotch blocks, skids, or like track-engaging shoes
    • B61H7/04—Scotch blocks, skids, or like track-engaging shoes attached to railway vehicles
    • B61H7/06—Skids
    • B61H7/08—Skids electromagnetically operated

Definitions

  • the present invention relates to an electromagnetic pad which can be used in particular for braking a rail vehicle by application to the steel running rail of this vehicle.
  • Skates of this type comprise a series of elementary trotting skids consisting of a ferromagnetic core, the two pole faces of which (north and south) separated by a vertical air gap are applied to the rail.
  • the ferromagnetic core cooperates with at least one excitation coil traversed by a direct electric current which causes the magnetic attraction of the pole faces by the running surface of the rail which closes the magnetic circuit.
  • the attraction force between the pole faces and the rail develops in a manner practically independent of the adhesion of the wheels of the rail vehicle on the rail, with the exception of the initial effort of applying the pad on the rail generally. greater than twice the action of gravity on the magnetic pad and its suspension and return system in the inactive position away from the rail.
  • the force of attraction between the skate and the rail can reach very large values which represent more than 20 times the action of gravity on the skate and its suspension and recall system and which can be close to those of- the application effort on the rail of the wheels of a railway bogie framing this skate.
  • the retarding forces obtained with such pads during braking tests generally do not exceed values of 1000 to 1200 decanewtons (daN), which translates a relatively low coefficient of friction between the friction surface of the pads and the rail.
  • magnetic brake pads are used more and more on vehicles fast railways intended for the transport of passengers because their use, on the one hand practically does not require grip between the wheels and the rail and reduces stopping distances in the worst grip conditions, and on the other hand, can be considered to be safe when the pads are applied automatically in the event of emergency braking and are supplied with direct current by the vehicle's on-board batteries.
  • One of the aims of the present invention is to produce a magnetic pad, on the one hand compatible with the current requirements of weight, size, electrical excitation power and cost for the bogies of railway vehicles intended for transport. of travelers. and, on the other hand, whose effective braking performance on the track is considerably improved.
  • the electromagnetic pad which can be used in particular for braking a rail vehicle by application to the steel running rail of this vehicle, of the type comprising at least one elementary friction pad consisting of a ferromagnetic core, the two faces of which polar (north and south) separated by a vertical air gap are likely to apply quer on the rail, the core cooperating with at least one excitation coil capable of causing the magnetic attraction of these pole faces by the running surface of the rail which then closes the magnetic circuit, is characterized in that the ferromagnetic core and its faces fleeces likely to be applied to the rail are made of a material with high magnetic permeability such as mild steel while a plate made of a material with good magnetic permeability, high coefficient of friction and good mechanical resistance such as '' an agglomerated and sintered powder based on soft iron or ferrites is attached and rigidly fixed on each pole face to come to come, when the pad is applied to the running rail, between the surface of this rail and the pole face made of material with high magnetic permeability.
  • the friction material most generally used up to now to produce the polar faces was a friction cast iron with good magnetic permeability but which nevertheless did not withstand as high inductions as mild steel. Thanks to the invention, it is possible to produce the magnetic circuit mainly in mild steel with high permeability and to really benefit from a high coefficient of friction between the surface of the poles and the rail. Sintered materials already exist which have a high permeability and a coefficient of friction of between 0.3 and 0.5. The interposition of plates of such a material between the pole faces and the rail should make it possible to triple the braking forces obtained with the magnetic pads without increasing their weight, size and electrical excitation.
  • the material with good magnetic permeability and high coefficient of friction also has properties of remanent magnetism capable of reinforcing the attraction force exerted by the running rail without preventing the return of the magnetic pad in the inactive position after the excitation coil is cut off.
  • a pad with a slight remanent magnetism can be applied to the rail without electrical excitation during the service braking of the vehicle in order to clean the surface of the rail wet or polluted by fatty products.
  • the application on the rail of such a pad can be carried out by the action of the braking pressure of the vehicle acting on one or more application pistons and the high coefficient of friction of the friction material of the poles makes it possible to obtain sensitive braking forces and effective cleaning of the surface of the rail without the return of the pad in the inactive position away from the rail, requires greater return efforts than those of the return springs usually used capable of exerting a force return substantially equal to twice the action of gravity on the skate and the movable part of its suspension and return system.
  • the material with good magnetic permeability and high coefficient of friction may also have good thermal conductivity and be connected to the minus a block of heat accumulation capable of reducing, during braking, the heating of the material to good thermal conductivity and, consequently, of the rail.
  • the material with good magnetic permeability and a high coefficient of friction may have qualities of fragmentation with friction abrasion (of the type of those of cast iron railway brake shoes) making it possible to evacuate into fragments of abrasion a significant part of the friction heat released during the friction of the pad on the rail.
  • the material with good magnetic permeability and high coefficient of friction also has high abrasion resistance and is applied in a thin layer on the polar faces by a fastening means. such as a metallization projection.
  • Another embodiment of the invention consists in forming the material with good magnetic permeability and high coefficient of friction into a massive block of friction pad with high magnetic permeability removably attached to each of the pole faces by any means achieving the continuity of the magnetic circuit passing through the ferromagnetic core.
  • the two friction shoe blocks corresponding to the two poles (north and south) of an elementary friction shoe can be assembled in a single monoblock, on the one hand consisting of the two shoe blocks separated by a continuous strip of nonmagnetic material (s) to constitute the air gap between the two poles, on the other hand, removably fixed between and on the two pole faces by any means providing continuity of the magnetic circuit.
  • the continuous strip of non-magnetic material (s) may contain a block of heat accumulation such as a fusible wax and have a flared section in the direction of the excitation coil to form a gap of minimum width at the outlet. between the two poles of the single monobloc on the side of the rail.
  • the continuous strip of non-magnetic material (s) is secured by sintering to the two friction shoe blocks corresponding to the two poles and the single monoblock is, on the one hand, tightened and assembled removably by any suitable means such as screws between the opposite lateral polar faces formed on each pole of the magnetic core and on the other hand, supported by each of these lateral faces on another polar face formed parallel to the surface of the rail on each pole of the nucleus.
  • the opposite side polar faces formed on each pole of the magnetic core preferably has a limited height allowing, in the inactive position of the magnetic pad mounted on the railway vehicle, to release towards the rail or respectively to engage from the rail, the single monoblock after removal of the assembly means of this monoblock on the poles of the magnetic core.
  • the single monoblocks can be slid laterally between the two opposite lateral polar faces formed on each pole of the core after depositing their assembly means on the poles of the magnetic core, to a lateral position outside the magnetic pad to allow the installation and / or removal of the monoblocks parallel to the rail.
  • the two opposite lateral faces formed on each pole of the core can be inclined symmetrically with respect to the longitudinal axis of the shoe and form two retaining surfaces for the single monoblock assembled in dovetail between the two polar faces of the ferromagnetic core.
  • the continuous central strip made of non-magnetic material (s) of the single monoblock can be provided with teeth and / or projections capable of cooperating with teeth and / or conjugate projections formed on a rigid envelope of the excitation coil in order to transmit to this rigid envelope the friction forces developed by the rail on the part of the single piece in contact with the rail.
  • the reference numeral 1 designates an electromagnetic pad supported by the bogie 2 of a railway vehicle by means of the piston rods 4a and 4b of two lifting cylinders, the action is shown diagrammatically by arrows 4.
  • Annular excitation coils 6, housed inside a rigid envelope 5, are aligned in the longitudinal direction of the rail 3. These coils have a vertical plane of symmetry 7 (see Figures 1 and 2) extending over the entire height of the pad and substantially coincident in service with the longitudinal plane of symmetry of the rail 3.
  • the pad 1 comprises a senna elementary friction pads 8 mounted in line and arranged between two head elements 9 along the rigid casing 5 forming a supporting frame so that each elementary pad is associated with its own coil 6.
  • the elementary end pads 9 are each provided with a chamfer 18 allowing them to engage the rail 3 progressively and thus to cross without snagging a sudden discontinuity in the rolling surface such as a rail joint or a switch fitting.
  • each elementary pad 8 applied to the running surface of the mushroom 3a of the rail 3 comprises a ferromagnetic core in the shape of an inverted U, the two branches 10 of which start from the central opening 6a of the coil 6 towards the rail 3 by supporting this coil 6 on either side so as to form at one of their ends two pole faces 11, which come opposite the upper surface of the rail 3 perpendicular to the longitudinal axis thereof.
  • the two branches of the U pass horizontally through the central opening of the coil 6 and are applied one on the other by a bearing surface 12, flat and without air gap to form the magnetic circuit of each elementary pad 8 in two easily removable parts 13 and 14 on either side of the plane of symmetry 7.
  • Each part 13 or 14 has at its base a friction end piece 15 returning under the coil 6, directed vertically towards the rail 3 and kept away from the homologous end piece of the other part 13 or 14 by means of a separation strip 16 made of a non-magnetic material such as brass or stainless steel.
  • the two removable parts 13 and 14 constituting the ferromagnetic core of each elementary shoe 8, are tightened one on the other directly by the bearing surface 12 and on the separation strip 16 by transverse bolts 17, including the one crosses the surface 12 and can be made of a material with high magnetic permeability while the other, passing through a space provided at the base of the coil 6, crosses respectively the recessed portions 15 of the branches 10 and the separation strip 16 and must imperatively be made of a non-magnetic material such as stainless steel to avoid a magnetic short circuit of the air gap formed by the strip 16.
  • the pole faces 11 of parts 13 and 14 are covered with a thin plate 19 made of a material with good magnetic permeability, high coefficient of friction, good mechanical strength and with good resistance to wear. 'abrasion.
  • a thin plate 19 made of a material with good magnetic permeability, high coefficient of friction, good mechanical strength and with good resistance to wear. 'abrasion.
  • Such plates are now produced by powder metallurgy, in particular by sintering, but their attachment, which can be achieved by screws fixed perpendicular to the running surface of the rail 3, presents difficulties when they are thin.
  • the material interposed between the surface of the rail and the pole faces has a high abrasion resistance, it can be envisaged to hang it on these pole faces in a thin layer by metatization, that is to say projection at high impact speed in the form of molten or microfused particles.
  • the coil 6 is traversed by a direct current supplying a large number of ampere-turns of excitation capable of quasi-saturating the magnetic circuit closed on the parts 13 and 14 and on the rail where the magnetic flux enters via one of the pole faces 11 and exits through the other by making in the rail a path in the form of arcs of concentric circles represented in fine lines 20.
  • the separation strip 16 and the non-magnetic rod of the lower bolt 17 in effect force the magnetic flux to preferably pass through the relatively relatively permeable rail to the force lines to connect the north and south poles of the polar faces 11.
  • Induction high which crosses the running surface of the head 3a of the rail 3 causes a very large magnetic attraction force between the plates 19 and this surface of the rail.
  • the force of application of the plates 19 on the rail can thus reach, for the longest magnetic pads, static values of 7000 to 10,000 daN.
  • the rapid displacement of the magnetic pad on the rail induces in it eddy currents which reduce the magnetic induction crossing the surface of the rail but the high coefficient of friction of the plates 19 causes a significant braking force applied by the mushroom 3a of the rail to the plates 19 which transmit it to the parts 13 and 14 of the ferromagnetic core which then comes to bear on the lateral faces of the opening 6a of the coil 6 contained in the rigid casing 5 which abuts on the chassis of the bogie 2 of the vehicle.
  • the known type of magnetic pads have ferromagnetic cores which are either solid cast iron of relatively good magnetic permeability, or cast steel of very good magnetic permeability with friction pads added in friction cast iron of medium magnetic permeability.
  • the permeability of the magnetic circuit of such cores remains lower than that obtained with the magnetic pads represented in FIG. 1.
  • the magnetic shoe represented in section in FIG. 2 takes up certain elements from that represented in FIG. 1.
  • the identical elements have the same references and relate to the excitation coil 6, the branches 10 of the ferromagnetic core in two parts 13 and 14 and their common bearing surface 12.
  • the bolts 17 are replaced by screws 17 with hexagon socket on the outside, the part 13 of mild steel being molded provided with tapped holes to receive the threaded ends of these screws 17.
  • the end piece 15 at the base of parts 13 and 14 of the magnetic core is not extended in the direction of the rail but is provided with two perpendicular bearing faces between them respectively, 21 parallel to the plane of symmetry 7 and 22, parallel to the running surface of the rail.
  • a massive friction block 23 comprising two massive poles 24 and 25 made of a material of good magnetic permeability with a high coefficient of friction and good mechanical strength (for example molded by powder metallurgy and a sintering operation, in a single monobloc 23 comprising a separation strip 26 constituting the air gap between the two poles 11) is assembled on the magnetic core by means of lateral support faces conjugate of the faces 21 and 22 (of the parts 13 and 14 of the core) and is clamped between the two faces 21 by the lower screws 17 passing with clearance a bore 27 formed for example by molding in the block 23.
  • the separation strip 26 is made of a non-magnetic material by any suitable means, in particular by powder metallurgy and may have a flared section towards the top of the figure in the direction of the coil 6, as shown in the figure.
  • This flared section allows on the one hand to have a very long air gap in the vicinity of the coil 6 in an area most at risk of magnetic short-circuits by leakage induction and on the other hand to reduce to a small width l 'gap between the two poles in the vicinity of the friction surface on the rail.
  • This arrangement makes it possible to increase the contact surface between the friction pads and the rail and to increase the induction passing through this surface and thereby increasing the attraction force between the magnetic pad and the rail.
  • the monoblocks 23 mounted on the head friction shoes 9 are provided with the chamfer 18 already described with reference to FIG. 3, and with an external lateral fin 28 allowing the monoblock to hang on to the rail in the event that, at the time of the 'application of the pad in the direction of the rail, a transverse impact laterally displaces all of the two magnetic pads of a bogie connected together by a front and lateral abutment frame on the bogie frame.
  • the solid block 23 for materials less resistant to abrasion wear than in the case of FIG. 1 because the change of the blocks 23 can easily take place on the pad mounted on the bogie 2. It it suffices to unscrew the lower screws 17 made of stainless steel. and to lower the blocks 23 onto the rail with a lever, the magnetic pad being in the inactive upper position as shown in FIG. 3. The blocks can then be removed laterally 23 if the lowering height of the rail is greater than the / height of the face 21. in the case where this face 21 is higher than the free space between the pole face 11 and the rail, can take out the blocks 23 by sliding them, after loosening the lower screws 17, between the faces 21 to a free end of the shoe beyond the end shoe 9.
  • the solid poles 24 and 25 can be entirely separated from the strip 26 on which they are tightened by the lower screws 17.
  • the strip 26 can have various cross sections, in particular a rectangular section of known type facilitating the tightening of the solid poles between the two faces 21 and it can be provided with teeth and / or projections cooperating with teeth and / or conjugate projections formed on the rigid casing 5 preferably made of stainless steel sheet for. limit magnetic leaks.
  • the clearance provided between the bore 27 and each screw 17 which passes therethrough enables the solid poles 24 and 25 to be tightened energetically between the faces 21 while allowing free expansion in the vertical direction of these poles when they are brought to high temperature by friction on the rail.
  • the material which constitutes them has abrasion fragmentation qualities to evacuate (like the phosphorous melting of the railway brake shoes) the heat of friction in the abrasion fragments then brought to red or else that the separation strip 26 contains a block of heat accumulation in non-magnetic material such as a fusible wax.
  • the present invention is not limited to the embodiments shown. It is susceptible of numerous variants, accessible to those skilled in the art, without departing from the spirit of the invention.
  • the magnetic pad comprises massive poles 24, 25 capable of being brought to high temperature by friction on the rail
  • faces 21 inclined symmetrically with respect to the axis 7 to form two surfaces downward retainer for the monobloc 23 which is then assembled in dovetail between the two faces 21 with a slight clearance allowing it to come to bear on the parts 13 and 14 by the faces 22 during braking.
  • the magnetic circuit has a slight gap between the poles 24 and 25 and the faces 21 but good contact between these poles 24 and 25 and the bearing surfaces 22.
  • the block 23 and the poles 24 and 25 can expand freely in all directions compared to the mild steel magnetic core. Such an arrangement proves to be particularly advantageous when the coefficients of expansion of the cores and of the block 23 are very different but requires relatively solid lower screws 17 to cope with the torsional and opening forces applied to this core when the magnetic pad is in rail service.
  • the use of dovetail monoblocks 23 requires the mounting by lateral sliding of these monoblocks from one of the ends of the magnetic pad.
  • this braking action by friction pad could be reinforced by permanent excitation magnets which do not prevent the pads from being returned to the inactive position, the well-known drawback of permanent magnets in rail service there being however hang all ferromagnetic particles passing in their vicinity.
  • Another variant consists in providing for the material of the poles 24 and 25 and possibly of the separation strip 26, a relatively elastic structure, which can be obtained by leaving voids between the grains of sintered material.
  • a relatively elastic structure allows the pole face 11 to better match the surface of the running rail under the action of the magnetic attraction force and therefore, to increase the magnetic induction in service and the magnetic attraction forces. and braking the pad on the rail.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Braking Arrangements (AREA)

Abstract

An electromagnetic skid, in particular for the braking of a railway vehicle by being applied to the rail on which the said vehicle runs, is of the type comprising a series of elementary friction skids (8). It comprises annular trip coils (6) whose median vertical plane of symmetry is oriented in the direction of the rail (3), and inverted U-shaped removable ferromagnetic cores (8) which are perpendicular to the rail (3) and are provided with friction plates (19). Application to railway braking by means of magnetised skids solidly fixed to the bogie to obtain friction on the running rail without resort to adhesion. <IMAGE>

Description

La présente invention se rapporte à un patin électromagnétique utilisable en particulier pour le freinage d'un véhicule ferroviaire par application sur le rail de roulement en acier de ce véhicule.The present invention relates to an electromagnetic pad which can be used in particular for braking a rail vehicle by application to the steel running rail of this vehicle.

Les patins de ce type comportent une série de patins trotteurs élémentaires constitués d'un noyau ferromagnétique dont les deux faces polaires, (nord et sud) séparées par un entrefer vertical sont appliquées sur le rail. Au moment du freinage, le noyau ferromagnétique coopère avec au moins une bobine excitatrice parcourue par un courant électrique continu qui provoque l'attraction magnétique des faces polaires par la surface de roulement du rail qui ferme le circuit magnétique.Skates of this type comprise a series of elementary trotting skids consisting of a ferromagnetic core, the two pole faces of which (north and south) separated by a vertical air gap are applied to the rail. At the time of braking, the ferromagnetic core cooperates with at least one excitation coil traversed by a direct electric current which causes the magnetic attraction of the pole faces by the running surface of the rail which closes the magnetic circuit.

L'effort d'attraction entre les faces polaires et le rail se développe de façon pratiquement indépendante de l'adhérence des roues du véhicule ferroviaire sur le rail, à l'exception de l'effort initial d'application du patin sur le rail généralement supérieur au double de l'action de la pesanteur sur le patin magnétique et son système de suspension et de rappel en position inactive à distance du rail.The attraction force between the pole faces and the rail develops in a manner practically independent of the adhesion of the wheels of the rail vehicle on the rail, with the exception of the initial effort of applying the pad on the rail generally. greater than twice the action of gravity on the magnetic pad and its suspension and return system in the inactive position away from the rail.

L'effort d'attraction entre le patin et le rail peut atteindre des valeurs très importantes qui représentent plus de 20 fois l'action de la pesanteur sur le patin et son système de suspension et de rappel et qui peuvent être voisines de celles de-l'effort d'application sur le rail des roues d'un bogie ferroviaire encadrant ce patin. A titre d'exemple, on peut indiquer que les deux patins magnétiques d'un bogie ferroviaire pèsent environ 1/2 tonne avec leur équipement mobile d'application et de relevage mais peuvent être appliqués sur le rail par l'attraction électromagnétique avec un effort d'attraction maximal d'environ 14 000 daN. Les efforts retardateurs obtenus avec de tels patins au cours des essais de freinage ne dépassent en général pas des valeurs de 1 000 à 1 200 décanewtons (daN) ce qui traduit un coefficient de frottement relativement faible entre la surface de friction des patins et le rail ainsi qu'une diminution de l'induction traversant la surface du rail lorsque le patin se déplace sur le rail. En dépit de ces performances de freinage apparemment modestes, les patins magnétiques de freinage sont de plus en plus utilisés sur les véhicules ferroviaires rapides destinés au transport de voyageurs car leur usage, d'une part ne sollicite pratiquement pas d'adhérence entre les roues et le rail et réduit les distances d'arrêt dans les pires conditions d'adhérence, et d'autre part, peut être considéré comme de sécurité lorsque les patins sont appliqués automatiquement en cas de freinage d'urgence et sont alimentés en courant continu par les batteries de bord du véhicule. L'usage des patins magnétiques sur les véhicules ferroviaires légers pour le transport des voyageurs, tels que les trams, a toujours été très prisé car dans une telle application, il est possible d'alimenter le bobinage d'excitation électrique à grande puissance par prélèvement direct ou quasi-direct sur la caténaire à courant continu généralement à 600V, et la charge des bogies plus limitée, permet d'atteindre en freinage d'urgence des décélérations voisines de 3m/sec2.The force of attraction between the skate and the rail can reach very large values which represent more than 20 times the action of gravity on the skate and its suspension and recall system and which can be close to those of- the application effort on the rail of the wheels of a railway bogie framing this skate. As an example, we can indicate that the two magnetic pads of a railway bogie weigh around 1/2 ton with their mobile application and lifting equipment but can be applied to the rail by electromagnetic attraction with a force. maximum attraction of around 14,000 daN. The retarding forces obtained with such pads during braking tests generally do not exceed values of 1000 to 1200 decanewtons (daN), which translates a relatively low coefficient of friction between the friction surface of the pads and the rail. as well as a reduction in the induction crossing the surface of the rail when the shoe moves on the rail. Despite these apparently modest braking performance, magnetic brake pads are used more and more on vehicles fast railways intended for the transport of passengers because their use, on the one hand practically does not require grip between the wheels and the rail and reduces stopping distances in the worst grip conditions, and on the other hand, can be considered to be safe when the pads are applied automatically in the event of emergency braking and are supplied with direct current by the vehicle's on-board batteries. The use of magnetic pads on light rail vehicles for the transport of passengers, such as trams, has always been very popular because in such an application, it is possible to supply the high excitation electric excitation winding by sampling direct or almost direct on the direct current catenary, generally at 600V, and the more limited load of the bogies allows decelerations of around 3m / sec 2 to be reached in emergency braking.

De nombreux perfectionnements ont été proposés et/ou appliqués pour améliorer les performances de freinage des patins magnétiques. L'augmentation de l'excitation électrique ne peut être envisagée par suite de la quasi saturation des circuits magnétiques, non plus que l'augmentation des dimensions en largeur et en longueur qui se heurtent, respectivement à la largeur limitée du champignon du rail de roulement et à l'espace disponible entre les deux roues du bogie en dehors duquel il ne saurait être question de transmettre au véhicule les forces frottantes appliquées par le rail au patin. Un autre perfectionnement a consisté à ajouter entre les pôles magnétiques du patin, notamment dans l'entrefer entre ces deux pôles, des garnitures de friction à coefficient de frottement élevé. De telles garnitures se sont révélées pratiquement inefficaces car, ou bien leur effort d'application sur le rail est faible, ou bien la perméabilité entre les pôles du patin magnétique et le rail en est sérieusement affectée et le gain sur le coefficient de frottement est pratiquement annulé par la diminution de l'effort d'application magnétique du patin sur le rail.Many improvements have been proposed and / or applied to improve the braking performance of magnetic pads. The increase in the electrical excitation cannot be envisaged as a result of the virtual saturation of the magnetic circuits, no more than the increase in the dimensions in width and in length which collide, respectively with the limited width of the head of the running rail. and the space available between the two wheels of the bogie outside which there can be no question of transmitting to the vehicle the friction forces applied by the rail to the pad. Another improvement consisted in adding between the magnetic poles of the pad, in particular in the air gap between these two poles, friction linings with a high coefficient of friction. Such linings have proved to be practically ineffective because either their application force on the rail is low, or the permeability between the poles of the magnetic pad and the rail is seriously affected and the gain in the coefficient of friction is practically canceled by the reduction of the magnetic application force of the pad on the rail.

L'un des buts de la présente invention est de réaliser un patin magnétique, d'une part compatible avec les exigences actuelles de poids, d'encombrement, de puissance d'excitation électrique et de coût pour les bogies des véhicules ferroviaires destinés au transport de voyageurs.et, d'autre part, dont les performances effectives de freinage sur la voie sont améliorées de façon considérable.One of the aims of the present invention is to produce a magnetic pad, on the one hand compatible with the current requirements of weight, size, electrical excitation power and cost for the bogies of railway vehicles intended for transport. of travelers. and, on the other hand, whose effective braking performance on the track is considerably improved.

A cet effet, le patin électromagnétique utilisable en particulier pour le freinage d'un véhicule ferroviaire par application sur le rail de roulement en acier de ce véhicule, du type comportant au moins un patin frotteur élémentaire constitué d'un noyau ferromagnétique dont les deux faces polaires (nord et sud) séparées par un entrefer vertical sont susceptibles de venir s'appliquer sur le rail, le noyau coopérant avec au moins une bobine excitatrice apte à provoquer l'attraction magnétique de ces faces polaires par la surface de roulement du rail qui ferme alors le circuit magnétique, est caractérisé en ce que le noyau ferromagnétique et ses faces polaires susceptibles de s'appliquer sur le rail sont réalisés en un matériau à haute perméabilité magnétique tel que de l'acier doux tandis qu'une plaque en un matériau à bonne perméabilité magnétique, à coefficient de friction élevé et de bonne résistance mécanique tel qu'une poudre agglomérée et frittée à base de fer doux ou de ferrites est rapportée et fixée rigidement sur chaque face polaire pour venir s'interposer, lorsque le patin est appliqué sur le rail de roulement, entre la surface de ce rail et la face polaire en matériau à haute perméabilité magnétique. Le matériau de frottement le plus généralement utilisé jusqu'ici pour réaliser les faces polaires était une fonte de frottement à bonne perméabilité magnétique mais qui néanmoins ne supportait pas des inductions aussi élevées que l'acier doux. Grâce à l'invention, il est possible de réaliser le circuit magnétique principalement en acier doux à haute perméabilité et de bénéficier vraiment d'un coefficient de friction élevé entre la surface des pôles et le rail. Des matériaux frittés existent déjà qui possèdent une perméabilité élevée et un coefficient de frottement compris entre 0,3 et 0,5. L'interposition de plaques d'un tel matériau entre les faces polaires et le rail devrait permettre de tripler les forces freinantes obtenues avec les patins magnétiques sans augmenter leur poids, encombrement et excitation électrique.To this end, the electromagnetic pad which can be used in particular for braking a rail vehicle by application to the steel running rail of this vehicle, of the type comprising at least one elementary friction pad consisting of a ferromagnetic core, the two faces of which polar (north and south) separated by a vertical air gap are likely to apply quer on the rail, the core cooperating with at least one excitation coil capable of causing the magnetic attraction of these pole faces by the running surface of the rail which then closes the magnetic circuit, is characterized in that the ferromagnetic core and its faces fleeces likely to be applied to the rail are made of a material with high magnetic permeability such as mild steel while a plate made of a material with good magnetic permeability, high coefficient of friction and good mechanical resistance such as '' an agglomerated and sintered powder based on soft iron or ferrites is attached and rigidly fixed on each pole face to come to come, when the pad is applied to the running rail, between the surface of this rail and the pole face made of material with high magnetic permeability. The friction material most generally used up to now to produce the polar faces was a friction cast iron with good magnetic permeability but which nevertheless did not withstand as high inductions as mild steel. Thanks to the invention, it is possible to produce the magnetic circuit mainly in mild steel with high permeability and to really benefit from a high coefficient of friction between the surface of the poles and the rail. Sintered materials already exist which have a high permeability and a coefficient of friction of between 0.3 and 0.5. The interposition of plates of such a material between the pole faces and the rail should make it possible to triple the braking forces obtained with the magnetic pads without increasing their weight, size and electrical excitation.

Selon une autre caractéristique de l'invention, le matériau à bonne perméabilité magnétique et à coefficient de friction élevé possède également des propriétés de magnétisme rémanent aptes à renforcer l'effort d'attraction exercé par le rail de roulement sans interdire le rappel du patin magnétique en position inactive après coupure du courant de la bobine excitatrice. Un patin doté d'un léger magnétisme rémanent peut être appliqué sur le rail sans excitation électrique pendant le freinage de service du véhicule aux fins de nettoyer la surface du rail mouillée ou polluée par des produits gras. L'application sur le rail d'un tel patin peut être réalisée par l'action de la pression de freinage du véhicule agissant sur un ou plusieurs pistons d'application et le coefficient de friction élevé du matériau de frottement des pôles permet d'obtenir des forces freinantes sensibles et un nettoyage efficace de la surface du rail sans que le rappel du patin en position inactive à distance du rail, n'exige des efforts de rappel plus importants que ceux des ressorts de rappel habituellement utilisés capables d'exercer un effort de rappel sensiblement égal à deux fois l'action de la pesanteur sur le patin et la partie mobile de son système de suspension et de rappel.According to another characteristic of the invention, the material with good magnetic permeability and high coefficient of friction also has properties of remanent magnetism capable of reinforcing the attraction force exerted by the running rail without preventing the return of the magnetic pad in the inactive position after the excitation coil is cut off. A pad with a slight remanent magnetism can be applied to the rail without electrical excitation during the service braking of the vehicle in order to clean the surface of the rail wet or polluted by fatty products. The application on the rail of such a pad can be carried out by the action of the braking pressure of the vehicle acting on one or more application pistons and the high coefficient of friction of the friction material of the poles makes it possible to obtain sensitive braking forces and effective cleaning of the surface of the rail without the return of the pad in the inactive position away from the rail, requires greater return efforts than those of the return springs usually used capable of exerting a force return substantially equal to twice the action of gravity on the skate and the movable part of its suspension and return system.

Pour diminuer l'échauffement de la surface du rail en cas de défilement d'une longue rame de véhicules freinés par patins magnétiques, le matériau à bonne perméabilité magnétique et à coefficient de friction élevé peut posséder également une bonne conductibilité thermique et être relié à au moins un bloc d'accumulation de chaleur apte à diminuer au cours du freinage l'échauffement du matéri.au à bonne conductibilité thermique et, par voie de conséquence du rail.To reduce the heating of the surface of the rail in the event of the running of a long train of vehicles braked by magnetic pads, the material with good magnetic permeability and high coefficient of friction may also have good thermal conductivity and be connected to the minus a block of heat accumulation capable of reducing, during braking, the heating of the material to good thermal conductivity and, consequently, of the rail.

En variante, le matériau à bonne perméabilité magnétique et à coefficient de friction élevé peut posséder des qualités de fragmentation à l'abrasion par friction (du type de celles de la fonte des sabots de freins ferroviaires) permettant d'évacuer dans les fragments d'abrasion une part importante de la chaleur de frottement dégagée au cours de la friction du patin sur lé rail.As a variant, the material with good magnetic permeability and a high coefficient of friction may have qualities of fragmentation with friction abrasion (of the type of those of cast iron railway brake shoes) making it possible to evacuate into fragments of abrasion a significant part of the friction heat released during the friction of the pad on the rail.

Selon une autre caractéristique importante de l'invention, le matériau à bonne perméabilité magnétique et à coefficient de friction élevé est doté également d'une grande résistance à l'abrasion et est rapporté en couche mince sur les faces polaires par un moyen d'accrochage tel qu'une projection de métallisation.According to another important characteristic of the invention, the material with good magnetic permeability and high coefficient of friction also has high abrasion resistance and is applied in a thin layer on the polar faces by a fastening means. such as a metallization projection.

Une autre mode de réalisation de l'invention consiste à former le matériau à bonne perméabilité magnétique et à coefficient de friction élevé en un bloc massif de patin de friction à haute perméabilité magnétique fixé de façon amovible sur chacune des faces polaires par tout moyen réalisant la continuité du circuit magnétique traversant le noyau ferromagnétique. En perfectionnement de ce mode de réalisation, les deux blocs de patin de friction correspondant aux deux pôles (nord et sud) d'un patin frotteur élémentaire peuvent être assemblés en un monobloc unique, d'une part constitué des deux blocs de patin séparés par une bande continue en matériau(x) amagnêtique(s) pour constituer l'entrefer entre les deux pôles, d'autre part, fixé de façon amovible entre et sur les deux faces polaires par tout moyen réalisant la continuité du circuit magnétique. La bande continue en matériau(x) amagnétique(s) peut contenir un bloc d'accumulation de chaleur tel qu'une cire fusible et présenter une section évasée en direction de la bobine d'excitation pour former un entrefer de largeur minimale à la sortie entre les deux pôles du monobloc unique du côté du rail.Another embodiment of the invention consists in forming the material with good magnetic permeability and high coefficient of friction into a massive block of friction pad with high magnetic permeability removably attached to each of the pole faces by any means achieving the continuity of the magnetic circuit passing through the ferromagnetic core. In an improvement of this embodiment, the two friction shoe blocks corresponding to the two poles (north and south) of an elementary friction shoe can be assembled in a single monoblock, on the one hand consisting of the two shoe blocks separated by a continuous strip of nonmagnetic material (s) to constitute the air gap between the two poles, on the other hand, removably fixed between and on the two pole faces by any means providing continuity of the magnetic circuit. The continuous strip of non-magnetic material (s) may contain a block of heat accumulation such as a fusible wax and have a flared section in the direction of the excitation coil to form a gap of minimum width at the outlet. between the two poles of the single monobloc on the side of the rail.

Selon un mode de réalisation particulièrement compact et novateur, la bande continue en matériau(x) amagnêtique(s) est solidarisée par frittage aux deux blocs de patin de friction correspondant aux deux pôles et le monobloc unique est d'une part, serré et assemblé de façon amovible par tout moyen approprié tel que des vis entre les faces polaires latérales opposées ménagées sur chaque pôle du noyau magnétique et d'autre part, en appui par chacune de ces faces latérales sur une autre face polaire ménagée parallèlement à la surface du rail sur chaque pôle du noyau. Les faces polaires latérales opposées ménagées sur chaque pôle du noyau magnétique présentent de préférence une hauteur limitée permettant, en position inactive du patin magnétique monté sur le véhicule ferroviaire, de dégager vers le rail ou respectivement d'engager depuis le rail, le monobloc unique après dépose des moyens d'assemblage de ce monobloc sur les pôles du noyau magnétique. En variante, les monoblocs uniques peuvent être glissés latéralement entre les deux faces polaires latérales opposées ménagées sur chaque pôle du noyau après dépose de leurs moyens d'assemblage sur les pôles du noyau magnétique, jusqu'à une position latérale hors du patin magnétique pour permettre la pose et/ou la dépose des monoblocs parallèlement au rail. Pour l'assemblage sur le noyau magnétique, les deux faces latérales opposées ménagées sur chaque pôle du noyau peuvent être inclinés symétriquement par rapport à l'axe longitudinal du patin et former deux surfaces de retenue pour le monobloc unique assemblé en queue d'aronde entre les deux faces polaires du noyau ferromagnétique.According to a particularly compact and innovative embodiment, the continuous strip of non-magnetic material (s) is secured by sintering to the two friction shoe blocks corresponding to the two poles and the single monoblock is, on the one hand, tightened and assembled removably by any suitable means such as screws between the opposite lateral polar faces formed on each pole of the magnetic core and on the other hand, supported by each of these lateral faces on another polar face formed parallel to the surface of the rail on each pole of the nucleus. The opposite side polar faces formed on each pole of the magnetic core preferably has a limited height allowing, in the inactive position of the magnetic pad mounted on the railway vehicle, to release towards the rail or respectively to engage from the rail, the single monoblock after removal of the assembly means of this monoblock on the poles of the magnetic core. Alternatively, the single monoblocks can be slid laterally between the two opposite lateral polar faces formed on each pole of the core after depositing their assembly means on the poles of the magnetic core, to a lateral position outside the magnetic pad to allow the installation and / or removal of the monoblocks parallel to the rail. For assembly on the magnetic core, the two opposite lateral faces formed on each pole of the core can be inclined symmetrically with respect to the longitudinal axis of the shoe and form two retaining surfaces for the single monoblock assembled in dovetail between the two polar faces of the ferromagnetic core.

La bande centrale continue en matériau(x) amagnétique(s) du monobloc unique peut être munie de dents et/ou saillies aptes à coopérer avec des dents et/ou saillies conjuguées ménagées sur une enveloppe rigide de la bobine excitatrice afin de transmettre à cette enveloppe rigide les efforts de friction développés par le rail sur la partie du monobloc unique en contact avec le rail.The continuous central strip made of non-magnetic material (s) of the single monoblock can be provided with teeth and / or projections capable of cooperating with teeth and / or conjugate projections formed on a rigid envelope of the excitation coil in order to transmit to this rigid envelope the friction forces developed by the rail on the part of the single piece in contact with the rail.

D'autres buts, avantages et caractéristiques de la présente invention apparaîtront à la lecture de la description qui va suivre à titre non limitatif et en regard du dessin où:

  • . les figures 1 et 2 représentent en coupe transversale deux modes de réalisation différents du patin électromagnétique selon l'invention appliqué en position de freinage sur le raiT de roulement d'un véhicule ferroviaire.
  • . La figure 3 est une vue en élévation partielle d'un bogie de véhicule ferroviaire équipé de patins électromagnétiques conformes à l'invention.
Other objects, advantages and characteristics of the present invention will appear on reading the description which follows, without limitation, and with reference to the drawing in which:
  • . Figures 1 and 2 show in cross section two different embodiments of the electromagnetic pad according to the invention applied in the braking position on the running gear of a railway vehicle.
  • . Figure 3 is a partial elevational view of a rail vehicle bogie equipped with electromagnetic pads according to the invention.

En référence à la figure 3 qui représente un patin en service sur un véhicule, le repère 1 désigne un patin électromagnétique supporté par le bogie 2 d'un véhicule ferroviaire au moyen des tiges de piston 4a et 4b de deux cylindres de relevage dont l'action est schématisée par des flèches 4. Des bobines annulaires d'excitation 6, logées à l'intérieur d'une enveloppe rigide 5, sont alignées dans le sens longitudinal du rail 3. Ces bobines présentent un plan vertical de symétrie 7 (voir les figures 1 et 2) s'étendant sur toute la hauteur du patin et sensiblement confondu en service avec le plan de symétrie longitudinal du rail 3. Le patin 1 comporte une séné de patins frotteurs élémentaires 8 montés en ligne et disposés entre deux éléments de tête 9 le long de l'enveloppe rigide 5 formant châssis porteur de manière que chaque patin élémentaire soit associé à sa propre bobine 6. Les patins élémentaires d'extrémité 9 sont pourvus chacun d'un chanfrein 18 leur permettant d'engager le rail 3 progressivement et de franchir ainsi sans accrochage une discontinuité brutale de la surface de roulement telle qu'un joint de rail ou un raccord d'aiguillage.With reference to FIG. 3 which represents a pad in service on a vehicle, the reference numeral 1 designates an electromagnetic pad supported by the bogie 2 of a railway vehicle by means of the piston rods 4a and 4b of two lifting cylinders, the action is shown diagrammatically by arrows 4. Annular excitation coils 6, housed inside a rigid envelope 5, are aligned in the longitudinal direction of the rail 3. These coils have a vertical plane of symmetry 7 (see Figures 1 and 2) extending over the entire height of the pad and substantially coincident in service with the longitudinal plane of symmetry of the rail 3. The pad 1 comprises a senna elementary friction pads 8 mounted in line and arranged between two head elements 9 along the rigid casing 5 forming a supporting frame so that each elementary pad is associated with its own coil 6. The elementary end pads 9 are each provided with a chamfer 18 allowing them to engage the rail 3 progressively and thus to cross without snagging a sudden discontinuity in the rolling surface such as a rail joint or a switch fitting.

Si l'on se refère maintenant à la figure 1, on voit que chaque patin élémentaire 8 appliqué sur la surface de roulement du champignon 3a du rail 3, comprend un noyau ferromagnétique en forme de U renversé, dont les deux branches 10 partent de l'ouverture centrale 6a de la bobine 6 vers le rail 3 en épaulant cette bobine 6 de part et d'autre de manière à former à l'une de leur extrémité deux faces polaires 11, qui viennent en face de la surface supérieure du rail 3 perpendiculairement à l'axe longitudinal de celui-ci. Les deux branches du U passent horizontalement à travers l'ouverture centrale de la bobine 6 et viennent s'appliquer l'une sur l'autre par une surface d'appui 12, plane et sans entrefer pour constituer le circuit magnétique de chaque patin élémentaire 8 en deux parties aisément amovibles 13 et 14 de part et d'autre du plan de symétrie 7.If we now refer to FIG. 1, we see that each elementary pad 8 applied to the running surface of the mushroom 3a of the rail 3, comprises a ferromagnetic core in the shape of an inverted U, the two branches 10 of which start from the central opening 6a of the coil 6 towards the rail 3 by supporting this coil 6 on either side so as to form at one of their ends two pole faces 11, which come opposite the upper surface of the rail 3 perpendicular to the longitudinal axis thereof. The two branches of the U pass horizontally through the central opening of the coil 6 and are applied one on the other by a bearing surface 12, flat and without air gap to form the magnetic circuit of each elementary pad 8 in two easily removable parts 13 and 14 on either side of the plane of symmetry 7.

Chaque partie 13 ou 14 comporte à sa base un embout de friction 15 rentrant sous la bobine 6, dirigé verticalement vers le rail 3 et maintenu à l'écart de l'embout homologue de l'autre partie 13 ou 14 au moyen d'une bande de séparation 16 en un matériau amagnétique tel que du laiton ou de l'acier inoxydable. Les deux parties amovibles 13 et 14 constituant le noyau ferromagnétique de chaque patin élémentaire 8, sont serrées l'une sur l'autre directement par la surface d'appui 12 et sur la bande de séparation 16 par des boulons transversaux 17, dont l'un traverse la surface 12 et peut être réalisé en un matériau à haute perméabilité magnétique tandis que l'autre, passant dans un espace ménagé à la base de la bobine 6, traverse respectivement les parties en retrait 15 des branches 10 et la bande de séparation 16 et doit impérativement être réalisé en un matériau amagnétique tel que de l'acier inoxydable pour éviter un court- circuit magnétique de l'entrefer constitué par la bande 16.Each part 13 or 14 has at its base a friction end piece 15 returning under the coil 6, directed vertically towards the rail 3 and kept away from the homologous end piece of the other part 13 or 14 by means of a separation strip 16 made of a non-magnetic material such as brass or stainless steel. The two removable parts 13 and 14 constituting the ferromagnetic core of each elementary shoe 8, are tightened one on the other directly by the bearing surface 12 and on the separation strip 16 by transverse bolts 17, including the one crosses the surface 12 and can be made of a material with high magnetic permeability while the other, passing through a space provided at the base of the coil 6, crosses respectively the recessed portions 15 of the branches 10 and the separation strip 16 and must imperatively be made of a non-magnetic material such as stainless steel to avoid a magnetic short circuit of the air gap formed by the strip 16.

Conformément à l'invention, les faces polaires 11 des parties 13 et 14 sont couvertes d'une plaque mince 19 en un matériau de bonne perméabilité magnétique, de coefficient de friction élevé, de bonne résistance mécanique et doté d'une bonne résistance à l'abrasion. De telles plaques sont maintenant réalisées par la métallurgie des poudres, notamment par frittage mais leur accrochage qui peut être réalisé par des vis fixées perpendiculairement à la surface de roulement du rail 3, présente des difficultés lorsqu'elles sont de faible épaisseur. Dans le cas où le matériau interposé entre la surface du rail et les faces polaires présente une grande résistance à l'abrasion, on peut envisager de l'accrocher sur ces faces polaires en couche mince par mêtatlisation, c'est-à-dire projection à grande vitesse d'impact sous forme de particules fondues ou microfondues.According to the invention, the pole faces 11 of parts 13 and 14 are covered with a thin plate 19 made of a material with good magnetic permeability, high coefficient of friction, good mechanical strength and with good resistance to wear. 'abrasion. Such plates are now produced by powder metallurgy, in particular by sintering, but their attachment, which can be achieved by screws fixed perpendicular to the running surface of the rail 3, presents difficulties when they are thin. In the case where the material interposed between the surface of the rail and the pole faces has a high abrasion resistance, it can be envisaged to hang it on these pole faces in a thin layer by metatization, that is to say projection at high impact speed in the form of molten or microfused particles.

Lorsque le patin magnétique représenté sur la figure 1 est appliqué en position active sur le rail et glisse sur celui-ci, la bobine 6 est parcourue par un courant continu fournissant un grand nombre d'ampères-tours d'excitation capables de quasi-saturer le circuit magnétique fermé sur les parties 13 et 14 et sur le rail où le flux magnétique entre par l'une des faces polaires 11 et ressort par l'autre en réalisant dans le rail un parcours en forme d'arcs de cercles concentriques représentés en traits fins 20. La bande de séparation 16 et la tige amagnétique du boulon inférieur 17 obligent en effet le flux magnétique à traverser préférentiellement le rail relativement plus perméable aux lignes de force pour relier les pôles nord et sud des faces polaires 11. L'induction élevée qui traverse la surface de roulement du champignon 3a du rail 3 provoque un effort d'attraction magnétique très important entre les plaques 19 et cette surface du rail. L'effort d'application des plaques 19 sur le rail peut ainsi atteindre pour les plus longs patins magnétiques des valeurs statiques de 7000 à 10000 daN. Le déplacement rapide du patin magnétique sur le rail induit dans celui-ci des courants de Foucault qui réduisent l'induction magnétique traversant la surface du rail mais le coefficient de friction élevé des plaques 19 provoque un effort de freinage important appliqué par le champignon 3a du rail aux plaques 19 qui le transmettent aux parties 13 et 14 du noyau ferromagnétique qui vient alors en appui sur les faces latérales de l'ouverture 6a de la bobine 6 contenue dans l'enveloppe rigide 5 qui vient en butée sur le châssis du bogie 2 du véhicule.When the magnetic pad shown in FIG. 1 is applied in the active position on the rail and slides on it, the coil 6 is traversed by a direct current supplying a large number of ampere-turns of excitation capable of quasi-saturating the magnetic circuit closed on the parts 13 and 14 and on the rail where the magnetic flux enters via one of the pole faces 11 and exits through the other by making in the rail a path in the form of arcs of concentric circles represented in fine lines 20. The separation strip 16 and the non-magnetic rod of the lower bolt 17 in effect force the magnetic flux to preferably pass through the relatively relatively permeable rail to the force lines to connect the north and south poles of the polar faces 11. Induction high which crosses the running surface of the head 3a of the rail 3 causes a very large magnetic attraction force between the plates 19 and this surface of the rail. The force of application of the plates 19 on the rail can thus reach, for the longest magnetic pads, static values of 7000 to 10,000 daN. The rapid displacement of the magnetic pad on the rail induces in it eddy currents which reduce the magnetic induction crossing the surface of the rail but the high coefficient of friction of the plates 19 causes a significant braking force applied by the mushroom 3a of the rail to the plates 19 which transmit it to the parts 13 and 14 of the ferromagnetic core which then comes to bear on the lateral faces of the opening 6a of the coil 6 contained in the rigid casing 5 which abuts on the chassis of the bogie 2 of the vehicle.

Les patins magnétiques de type connu comportent des noyaux ferromagnétiques qui sont, soit massifs en fonte de relativement bonne perméabilité magnétique, soit en acier moulé à très bonne perméabilité magnétique avec des patins de friction rapportés en fonte de frottement de perméabilité magnétique moyenne. La perméabilité du circuit magnétique de tels noyaux reste inférieure à celle obtenue avec les patins magnétiques représentés sur la figure 1. Un tel avantage permet d'augmenter de façon sensible l'induction magnétique traversant la surface du rail et de bénéficier d'efforts d'attraction nettement plus importants du fait que ces efforts d'attraction sont proportionnels au carré de l'induction. Dans de tels patins, l'effort de retenue par les courants de Foucault est minoré le plus possible pour privilégier l'action du frottement entre les plaques 19 à haut coefficient de frottement (0,2 à 0,4) et le rail dont la rugosité de surface augmente après le passage abrasif du patin mégnétique du premier bogie d'un train, ce qui augmente l'efficacité des patins suivants.The known type of magnetic pads have ferromagnetic cores which are either solid cast iron of relatively good magnetic permeability, or cast steel of very good magnetic permeability with friction pads added in friction cast iron of medium magnetic permeability. The permeability of the magnetic circuit of such cores remains lower than that obtained with the magnetic pads represented in FIG. 1. Such an advantage makes it possible to appreciably increase the magnetic induction crossing the surface of the rail and to benefit from efforts of significantly greater attraction because these attraction forces are proportional to the square of the induction. In such pads, the retaining force by the eddy currents is reduced as much as possible to favor the action of friction between the plates 19 with a high coefficient of friction (0.2 to 0.4) and the rail whose surface roughness increases after the abrasive passage of the megetic pad of the first bogie of a train, which increases the efficiency of the following pads.

Le patin magnétique représenté en coupe sur la figure 2 reprend certains éléments de celui représenté sur la figure 1. Les éléments identiques portent les mêmes références et concernent la bobine d'excitation 6, les branches 10 du noyau ferromagnétique en deux parties 13 et 14 et leur surface d'appui commune 12.The magnetic shoe represented in section in FIG. 2 takes up certain elements from that represented in FIG. 1. The identical elements have the same references and relate to the excitation coil 6, the branches 10 of the ferromagnetic core in two parts 13 and 14 and their common bearing surface 12.

Pour des raisons de facilité de démontage depuis le côté extérieur (partie 14) du patin par rapport au châssis du bogie 2, les boulons 17 sont remplacés par des vis 17 à 6 pans creux du côté extérieur, la partie 13 en acier doux moulé étant munie de trous taraudés pour recevoir les embouts filetés de ces vis 17. L'embout 15 à la base des parties 13 et 14 du noyau magnétique n'est pas prolongé en direction du rail mais est muni de deux faces d'appui perpendiculaires entre elles respectivement, 21 parallèle au plan de symétrie 7 et 22, parallèle à la surface de roulement du rail.For reasons of ease of dismantling from the outside (part 14) of the shoe relative to the chassis of the bogie 2, the bolts 17 are replaced by screws 17 with hexagon socket on the outside, the part 13 of mild steel being molded provided with tapped holes to receive the threaded ends of these screws 17. The end piece 15 at the base of parts 13 and 14 of the magnetic core is not extended in the direction of the rail but is provided with two perpendicular bearing faces between them respectively, 21 parallel to the plane of symmetry 7 and 22, parallel to the running surface of the rail.

Selon l'invention, un bloc massif de friction 23 comportant deux pôles massifs 24 et 25 en un matériau de bonne perméabilité magnétique à coéfficient de friction élevé et de bonne résistance mécanique (par exemple moulés par la métallurgie des poudres et une opération de frittage, en un monobloc unique 23 comportant une bande de séparation 26 constituant l'entrefer entre les deux pôles 11) est assemblée sur le noyau magnétique par l'intermédiaire de faces latérales d'appui conjuguées des faces 21 et 22 (des parties 13 et 14 du noyau) et est serré entre les deux faces 21 par les vis inférieures 17 traversant avec jeu un alésage 27 ménagé par exemple par moulage dans le bloc 23. La bande de séparation 26 est réalisé en un matériau amagnétique par tout moyen convenable, notamment par la métallurgie des poudres et peut présenter une section évasée vers le haut de la figure en direction de la bobine 6, tel que représenté sur la figure. Cette section évasée permet d'une part de disposer d'un entrefer de grande longueur au voisinage de la bobine 6 dans une zone risquant le plus les court-circuits magnétiques par induction de fuite et d'autre part de réduire à une faible largeur l'entrefer entre les deux pôles au voisinage de la surface de friction sur le rail. Cette disposition permet d'augmenter la surface de contact entre les patins de friction et le rail et d'augmenter l'induction traversant cette surface et partant d'augmenter l'effort d'attraction entre le patin magnétique et le rail. Les monoblocs 23 montés sur les patins frotteurs de tête 9 sont munis du chanfrein 18 déjà décrit en référence à la figure 3, et d'un aileron latéral extérieur 28 permettant au monobloc de se raccrocher au rail dans le cas où, au moment de l'application du patin en direction du rail, un choc transversal déporte latéralement l'ensemble des deux patins magnétiques d'un bogie reliés entre eux par un cadre de butée frontale et latérale sur le châssis de bogie.According to the invention, a massive friction block 23 comprising two massive poles 24 and 25 made of a material of good magnetic permeability with a high coefficient of friction and good mechanical strength (for example molded by powder metallurgy and a sintering operation, in a single monobloc 23 comprising a separation strip 26 constituting the air gap between the two poles 11) is assembled on the magnetic core by means of lateral support faces conjugate of the faces 21 and 22 (of the parts 13 and 14 of the core) and is clamped between the two faces 21 by the lower screws 17 passing with clearance a bore 27 formed for example by molding in the block 23. The separation strip 26 is made of a non-magnetic material by any suitable means, in particular by powder metallurgy and may have a flared section towards the top of the figure in the direction of the coil 6, as shown in the figure. This flared section allows on the one hand to have a very long air gap in the vicinity of the coil 6 in an area most at risk of magnetic short-circuits by leakage induction and on the other hand to reduce to a small width l 'gap between the two poles in the vicinity of the friction surface on the rail. This arrangement makes it possible to increase the contact surface between the friction pads and the rail and to increase the induction passing through this surface and thereby increasing the attraction force between the magnetic pad and the rail. The monoblocks 23 mounted on the head friction shoes 9 are provided with the chamfer 18 already described with reference to FIG. 3, and with an external lateral fin 28 allowing the monoblock to hang on to the rail in the event that, at the time of the 'application of the pad in the direction of the rail, a transverse impact laterally displaces all of the two magnetic pads of a bogie connected together by a front and lateral abutment frame on the bogie frame.

Lorsque le patin magnétique représenté sur la figure 2 est appliqué en position active sur le rail et glisse sur celui-ci, la bobine 6 étant parcourue par un courant continu d'excitation, le flux magnétique traverse les faces 21 et 22 pratiquement sans entrefer, s'étale dans le pôle massif 25 de bonne perméabilité magnétique, entre par l'une des faces polaires 11 et ressort par l'autre en réalisant dans le rail un parcours en forme d'arcs de cercles concentriques représentés en traits fins 20 et revient par le pôle massif 24 dans la partie 14 du noyau, sans traverser la bande de séparation 26 constituant un entrefer de largeur variable. L'attraction magnétique-développée entre les pôles 24 et 25 et le rail produit des efforts de frottement importants par suite du coefficient de frottement élevé du matériau fritté constituant les pôles et du matériau amagnétique constituant la bande de séparation 26. Dans cette version, il est possible d'utiliser pour-le bloc massif 23 des matériaux moins résistant à l'usure par abrasion que dans le cas de la figure 1 car le changement des blocs 23 peut s'opérer aisément sur le patin monté sur le bogie 2. Il suffit pour cela de dévisser les vis inférieures 17 en acier inoxydable .et de faire descendre les blocs 23 sur le rail avec un levier, lé patin magnétique étant en position inactive haute telle que représentée sur la figure 3. On peut alors retirer latéralement les blocs 23 si la hauteur de descente sur le rail est supérieure à la/hauteur de la face 21. Dans le cas où cette face 21 est plus haute que l'espace libre entre la face polaire 11 et le rail, on peut sortir les blocs 23 en les faisant glisser, après desserrage des vis inférieures 17, entre les faces 21 jusqu'à une extrémité libre du patin au-delà du patin d'extrémité 9. On doit comprendre également que les pôles massifs 24 et 25 peuvent être entièrement séparés de la bande 26 sur laquelle ils sont serrés par les vis inférieures 17. La bande 26 peut présenter diverses sections transversales, notamment une section rectangulaire de type connu facilitant le serrage des pôles massifs entre les deux faces 21 et elle peut être munie de dents et/ou de saillies coopérant avec des dents et/ou saillies conjuguées ménagées sur l'enveloppe rigide 5 réalisée de préférence en tôle d'acier inoxydable pour. limiter les fuites magnétiques.When the magnetic pad shown in FIG. 2 is applied in the active position on the rail and slides on it, the coil 6 being traversed by a continuous excitation current, the magnetic flux crosses the faces 21 and 22 practically without air gap, spreads out in the solid pole 25 of good magnetic permeability, enters through one of the polar faces 11 and emerges through the other by making a path in the rail in the form of arcs of concentric circles represented in thin lines 20 and returns by the solid pole 24 in part 14 of the core, without crossing the separation strip 26 constituting an air gap of variable width. The magnetic-developed attraction between the poles 24 and 25 and the rail produces significant friction forces owing to the high coefficient of friction of the sintered material constituting the poles and of the non-magnetic material constituting the separation strip 26. In this version, it it is possible to use the solid block 23 for materials less resistant to abrasion wear than in the case of FIG. 1 because the change of the blocks 23 can easily take place on the pad mounted on the bogie 2. It it suffices to unscrew the lower screws 17 made of stainless steel. and to lower the blocks 23 onto the rail with a lever, the magnetic pad being in the inactive upper position as shown in FIG. 3. The blocks can then be removed laterally 23 if the lowering height of the rail is greater than the / height of the face 21. in the case where this face 21 is higher than the free space between the pole face 11 and the rail, can take out the blocks 23 by sliding them, after loosening the lower screws 17, between the faces 21 to a free end of the shoe beyond the end shoe 9. It should also be understood that the solid poles 24 and 25 can be entirely separated from the strip 26 on which they are tightened by the lower screws 17. The strip 26 can have various cross sections, in particular a rectangular section of known type facilitating the tightening of the solid poles between the two faces 21 and it can be provided with teeth and / or projections cooperating with teeth and / or conjugate projections formed on the rigid casing 5 preferably made of stainless steel sheet for. limit magnetic leaks.

On doit comprendre également que le jeu prévu entre l'alésage 27 et chaque vis 17 qui le traverse permet de serrer énergiquement les pôles massifs 24 et 25 entre les faces 21 tout en autorisant la libre dilatation dans le sens vertical de ces pôles lorsqu'ils sont portés à température élevée par la friction sur le rail. Pour réduire l'échauffement du rail et de ces pôles au cours du freinage, on peut prévoir que le matériau qui les constitue possède des qualités de fragmentation à l'abrasion pour évacuer (comme la fonte phosphoreuse des sabots de frein ferroviaire) une partie de la chaleur de frottement dans les fragments d'abrasion portés alors au rouge ou bien que la bande de séparation 26 contient un bloc d'accumulation de chaleur en matériau amagnétique tel qu'une cire fusible.It should also be understood that the clearance provided between the bore 27 and each screw 17 which passes therethrough enables the solid poles 24 and 25 to be tightened energetically between the faces 21 while allowing free expansion in the vertical direction of these poles when they are brought to high temperature by friction on the rail. To reduce the heating of the rail and of these poles during braking, it is possible to provide that the material which constitutes them has abrasion fragmentation qualities to evacuate (like the phosphorous melting of the railway brake shoes) the heat of friction in the abrasion fragments then brought to red or else that the separation strip 26 contains a block of heat accumulation in non-magnetic material such as a fusible wax.

Bien entendu, la présente invention n'est pas limitée aux modes de réalisation représentés. Elle est susceptible de nombreuses variantes, accessibles à l'homme de l'art, sans que l'on ne s'écarte de l'esprit de l'invention. Ainsi, dans le cas où le patin magnétique comporte des pôles massifs 24, 25 susceptibles d'être portés à haute température par le frottement sur le rail, on peut prévoir des faces 21 inclinées symétriquement par rapport à l'axe 7 pour former deux surfaces de retenue vers le bas pour le monobloc 23 qui est alors assemblé en queue d'aronde entre les deux faces 21 avec un léger jeu lui permettant de venir en appui sur les parties 13 et 14 par les faces 22 au cours du freinage. Dans une telle disposition, le circuit magnétique présente un léger entrefer entre les pôles 24 et 25 et les faces 21 mais un bon contact entre ces pôles 24 et 25 et les surfaces d'appui 22. Le bloc 23 et les pôles 24 et 25 peuvent se dilater librement dans tous les sens par rapport au noyau magnétique en acier doux. Une telle disposition se révèle particulièrement avantageuse lorsque les coefficients de dilatation des noyaux et du bloc 23 sont très différents mais exige des vis inférieures 17 relativement solides pour faire face aux efforts de torsion et d'ouverture appliqués à ce noyau lorsque le patin magnétique est en service sur le rail. L'utilisation de monoblocs 23 à queue d'aronde exige le montage par glissement latéral de ces monoblocs à partir de l'une des extrémités du patin magnétique.Of course, the present invention is not limited to the embodiments shown. It is susceptible of numerous variants, accessible to those skilled in the art, without departing from the spirit of the invention. Thus, in the case where the magnetic pad comprises massive poles 24, 25 capable of being brought to high temperature by friction on the rail, it is possible to provide faces 21 inclined symmetrically with respect to the axis 7 to form two surfaces downward retainer for the monobloc 23 which is then assembled in dovetail between the two faces 21 with a slight clearance allowing it to come to bear on the parts 13 and 14 by the faces 22 during braking. In such an arrangement, the magnetic circuit has a slight gap between the poles 24 and 25 and the faces 21 but good contact between these poles 24 and 25 and the bearing surfaces 22. The block 23 and the poles 24 and 25 can expand freely in all directions compared to the mild steel magnetic core. Such an arrangement proves to be particularly advantageous when the coefficients of expansion of the cores and of the block 23 are very different but requires relatively solid lower screws 17 to cope with the torsional and opening forces applied to this core when the magnetic pad is in rail service. The use of dovetail monoblocks 23 requires the mounting by lateral sliding of these monoblocks from one of the ends of the magnetic pad.

L'utilisation de patins magnétiques dotés de parties frottantes, soit très résistantes à l'abrasion comme les plaques minces 19 de la figure 1, soit très faciles à remplacer sur le patin en service comme les monoblocs 23 de la figure 2, permet d'utiliser de tels patins en freinage de service. Dans cette application, la modérabilité du freinage, à défaut d'une modulation du courant d'excitation apparamment difficile et onéreuse à réaliser, pourrait être obtenue, comme décrit précédemment, en appliquant le patin sur le rail par l'action de la pression de freinage agissant sur au moins un piston d'application des patins à l'encontre des ressorts et autres moyens de rappel de ce patin en position inactive.The use of magnetic pads provided with friction parts, either very resistant to abrasion like the thin plates 19 of FIG. 1, or very easy to replace on the pad in service like the monoblocks 23 of FIG. 2, makes it possible to use such pads in service braking. In this application, the moderation of the braking, in the absence of a modulation of the apparently difficult and expensive excitation current, could be obtained, as described previously, by applying the shoe on the rail by the action of the pressure of braking acting on at least one piston for applying the pads against the springs and other means for returning this pad to the inactive position.

Comme décrit auparavant, cette action de freinage par patin de frottement pourrait être renforcée par des aimants permanents d'excitation n'interdisant pas le rappel des patins en position inactive, l'inconvénient bien connu des y aimants permanents en service ferroviaire étant cependant d'accrocher toutes les particules ferromagnétiques passant à leur voisinage.As described above, this braking action by friction pad could be reinforced by permanent excitation magnets which do not prevent the pads from being returned to the inactive position, the well-known drawback of permanent magnets in rail service there being however hang all ferromagnetic particles passing in their vicinity.

Une autre variante consiste à prévoir pour le matériau des pôles 24 et 25 et éventuellement de la bande de séparation 26, une structure relativement élastique, ce qui peut s'obtenir en laissant des vides entre les grains de matériau frittés. Une telle structure élastique permet à la face polaire 11 de mieux épouser la surface du rail de roulement sous l'action de l'effort d'attraction magnétique et partant, d'augmenter l'induction magnétique en service et les efforts d'attraction magnétique et de freinage du patin sur le rail.Another variant consists in providing for the material of the poles 24 and 25 and possibly of the separation strip 26, a relatively elastic structure, which can be obtained by leaving voids between the grains of sintered material. Such an elastic structure allows the pole face 11 to better match the surface of the running rail under the action of the magnetic attraction force and therefore, to increase the magnetic induction in service and the magnetic attraction forces. and braking the pad on the rail.

Claims (16)

1.- Patin électromagnétique utilisable en particulier pour le freinage d'un véhicule ferroviaire par application sur le rail de roulement en acier de ce véhicule, du type comportant au moins un patin frotteur élémentaire constitué d'un noyau ferromagnétique dont les deux faces polaires (nord et sud) séparées par un entrefer vertical sont susceptibles de venir s'appliquer sur le rail, le noyau coopérant avec au moins une bobine excitatrice apte à provoquer l'attraction magnétique de ces faces polaires par la surface de roulement du rail qui ferme alors le circuit magnétique, caractérisé en ce que le noyau ferromagnétique et ses faces polaires susceptibles de s'appliquer sur le rail sont réalisés en un matériau à haute perméabilité magnétique tel que de l'acier doux tandis qu'une plaque en un matériau à bonne perméabilité magnétique, à coefficient de friction élevé et de bonne résistance mécanique tel qu'une poudre agglomérée et frittée à base de fer doux ou de ferrites est rapportée et fixée rigidement sur chaque face polaire pour venir s'interposer, lorsque le patin est appliqué sur le rail de roulement, entre la surface de ce rail et le matériau à haute perméabilité magnétique de la face polaire.1.- Electromagnetic pad usable in particular for braking a rail vehicle by application to the steel running rail of this vehicle, of the type comprising at least one elementary friction pad consisting of a ferromagnetic core, the two polar faces of which ( north and south) separated by a vertical air gap are likely to be applied to the rail, the core cooperating with at least one excitation coil capable of causing the magnetic attraction of these pole faces by the running surface of the rail which then closes the magnetic circuit, characterized in that the ferromagnetic core and its polar faces capable of being applied to the rail are made of a material with high magnetic permeability such as mild steel while a plate of a material with good permeability magnetic, with a high coefficient of friction and good mechanical resistance such that an agglomerated and sintered powder based on soft iron or ferrites is added and rigidly fixed on each pole face to come to come, when the pad is applied to the running rail, between the surface of this rail and the material with high magnetic permeability of the pole face. 2.- Patin électromagnétique selon la revendication 1, caractérisé en ce que le matériau à bonne perméabilité magnétique et à coefficient de friction élevé possède également des propriétés de magnétisme rémanent aptes à renforcer l'effort d'attraction exercé par le rail de roulement sans interdire le rappel du patin magnétique en position inactive après coupure du courant de la bobine excitatrice.2.- electromagnetic shoe according to claim 1, characterized in that the material with good magnetic permeability and high coefficient of friction also has properties of remanent magnetism capable of reinforcing the attraction force exerted by the running rail without prohibiting the return of the magnetic shoe in the inactive position after cutting the current of the excitation coil. 3.- Patin électromagnétique selon la revendication 1 ou 2, caractérisé en ce que le matériau à bonne perméabilité magnétique et à coefficient de friction élevé possède également une bonne conductibilité thermique.3.- electromagnetic shoe according to claim 1 or 2, characterized in that the material with good magnetic permeability and high coefficient of friction also has good thermal conductivity. 4.- Patin électromagnétique selon la revendication 3, caractérisé en ce que le matériau à bonne conductibilité thermique est relié à au moins un bloc d'accumulation de chaleur apte à diminuer au cours du freinage l'échauffement du matériau à bonne conductibilité thermique et, par voie de conséquence, du rail.4.- electromagnetic shoe according to claim 3, characterized in that the material with good thermal conductivity is connected to at least one block of heat accumulation capable of reducing during braking the heating of the material with good thermal conductivity and, consequently, rail. 5.- Patin électromagnétique selon l'une des revendications 1 à 4, caractérisé en ce que le matériau à bonne perméabilité magnétique et à coefficient de friction élevé possède des qualités de fragmentation à l'abrasion par friction (du type de celles de la fonte des sabots de frein ferroviaires) permettant d'évacuer dans les fragments d'abrasion une part importante de la chaleur de frottement dégagée au cours de la friction du patin sur le rail.5.- electromagnetic shoe according to one of claims 1 to 4, characterized in that the material with good magnetic permeability and high coefficient of friction has fragmentation qualities to abrasion by friction (of the type of those of cast iron railway brake shoes) allowing a large part of the friction heat released during friction of the shoe on the rail to be removed from the abrasion fragments. 6.- Patin électromagnétique selon l'une des revendications 1 à 4, caractérisé en ce que le matériau à bonne perméabilité magnétique et à coefficient de friction élevé est doté également d'une grande résistance à l'abrasion et est rapporté en couche mince sur les faces polaires par un moyen d'accrochage tel qu'une projection de métallisation.6.- electromagnetic shoe according to one of claims 1 to 4, characterized in that the material with good magnetic permeability and high coefficient of friction is also endowed with a great resistance to abrasion and is reported in a thin layer on the polar faces by a hooking means such as a metallization projection. 7.- Patin électromagnétique selon l'une des revendications 1 à 5, caractérisé en ce que le matériau à bonne perméabilité magnétique et à coefficient de friction élevé est formé en un bloc massif de patin de friction à haute perméabilité magnétique fixé de façon amovible sur chacune des faces polaires par tout moyen réalisant la continuité du circuit magnétique traversant le noyau ferromagnétique.7.- electromagnetic pad according to one of claims 1 to 5, characterized in that the material with good magnetic permeability and high coefficient of friction is formed in a massive block of friction pad with high magnetic permeability removably attached to each of the pole faces by any means achieving continuity of the magnetic circuit passing through the ferromagnetic core. 8.- Patin électromagnétique selon la revendication 7, caractérisé en ce que les deux blocs de patin de friction correspondant aux deux pôles (nord et sud) d'un patin frotteur élémentaire sont assemblés en un monobloc unique, d'une part, constitué des deux blocs de patin séparés par une bande continue en matëriau(x) amagnétique(s) pour constituer l'entrefer entre les deux pôles, d'autre part, fixé de façon amovible entre et sur les deux faces polaires par tout moyen réalisant la continuité du circuit magnétique.8.- electromagnetic shoe according to claim 7, characterized in that the two friction shoe blocks corresponding to the two poles (north and south) of an elementary friction shoe are assembled in a single piece, on the one hand, consisting of two pad blocks separated by a continuous strip of non-magnetic material (s) to form the air gap between the two poles, on the other hand, removably fixed between and on the two pole faces by any means providing continuity of the magnetic circuit. 9.- Patin électromagnétique selon la revendication 8, caractérisé en ce que la bande continue en matériau(x) amagnétique(s) contient un bloc d'accumulation de chaleur tel qu'une cire fusible.9.- electromagnetic shoe according to claim 8, characterized in that the continuous strip of non-magnetic material (s) contains a heat accumulation block such as a fusible wax. 10.- Patin électromagnétique selon la revendication 8 ou 9, caractérisé en ce que la bande continue en matériau(x) amagnétique(s) présente une section évasée en direction de la bobine d'excitation pour former un entrefer de largeur minimale à la sortie entre les deux pôles du monobloc unique du côté du rail.10.- electromagnetic shoe according to claim 8 or 9, characterized in that the continuous strip of non-magnetic material (s) has a flared section in the direction of the excitation coil to form a gap of minimum width at the outlet between the two poles of the single piece on the side of the rail. 11.- Patin électromagnétique selon l'une des revendications 8 à 10, caractérisé en ce que la bande continue en matériau(x) amagnétique(s) est solidarisée par frittage aux deux blocs de patin de friction correspondant aux deux pôles.11.- electromagnetic pad according to one of claims 8 to 10, characterized in that the continuous strip of non-magnetic material (s) is secured by sintering to the two friction pad blocks corresponding to the two poles. 12.- Patin électromagnétique selon l'une des revendications 8 à 11, caractérisé en ce que le monobloc unique est, d'une part, serré et assemblé de façon amovible par tout moyen approprié tel que des vis entre les faces polaires latérales opposées, ménagées sur chaque pôle du noyau magnétique et, d'autre part, en appui par chacune de ces faces latérales sur une autre face polaire ménagée parallèlement à la surface du rail sur chaque pôle du noyau.12.- electromagnetic shoe according to one of claims 8 to 11, characterized in that the single piece is, on the one hand, tightened and assembled in a removable manner by any suitable means such as screws between the opposite lateral polar faces, formed on each pole of the magnetic core and, on the other hand, supported by each of these side faces on another pole face formed parallel to the surface of the rail on each pole of the core. 13.- Patin électromagnétique selon la revendication 12, caractérisé en ce que les faces polaires latérales opposées ménagées sur chaque pôle du noyau magnétique, présentent une hauteur limitée permettant, en position inactive du patin magnétique monté sur le véhicule ferroviaire, de dégager vers le rail ou respectivement d'engager depuis le rail le monobloc unique;après .dépose des moyens d'assemblage de ce monobloc sur les pôles du noyau magnétique.13.- electromagnetic pad according to claim 12, characterized in that the opposite lateral pole faces formed on each pole of the magnetic core, have a limited height allowing, in the inactive position of the magnetic pad mounted on the rail vehicle, to clear towards the rail or respectively to engage from the rail the single monoblock ; after .deposition of the means of assembly of this monoblock on the poles of the magnetic core. 14.- Patin électromagnétique selon la revendication 12 ou 13, caractérisé en ce que, en position sur le véhicule, le (ou les) monobloc(s) unique(s) peuvent être glissés latéralement entre les deux faces polaires latérales opposées ménagées sur chaque pôle du noyau, après dépose des moyens d'assemblage du (ou des) monobloc(s) sur les pôles du noyau magnétique, jusqu'à une position latérale hors du patin magnétique pour permettre la pose et/ou la dépose de ce (ou ces) monobloc(s) unique(s) parallèlement au rail.14.- electromagnetic shoe according to claim 12 or 13, characterized in that, in position on the vehicle, the single piece (s) can be slid laterally between the two opposite lateral polar faces formed on each pole of the core, after removal of the means for assembling the monoblock (s) on the poles of the magnetic core, to a lateral position outside the magnetic pad to allow the installation and / or removal of this (or these) single piece (s) parallel to the rail. 15.- Patin électromagnétique selon la revendication 14, caractérisé en ce que les deux faces latérales opposées ménagées sur chaque pôle du noyau sont inclinées symétriquement par rapport à l'axe longitudinal du patin et forment deux surfaces de retenue pour le monobloc unique assemblé "en queue d'aronde" entre les deux faces polaires du noyau ferromagnétique.15.- electromagnetic shoe according to claim 14, characterized in that the two opposite lateral faces formed on each pole of the core are symmetrically inclined relative to the longitudinal axis of the shoe and form two retaining surfaces for the single assembled piece "in dovetail "between the two polar faces of the ferromagnetic core. 16.- Patin électromagnétique selon l'une des revendications 8 à 15, caractérisé en ce que la bande centrale continue en matériau(x) amagnétique(s) du monobloc unique est munie de dents et/ou saillies aptes à coopérer avec des dents et/ou saillies conjuguées ménagées sur une enveloppe rigide de la bobine excitatrice afin de transmettre à cette enveloppe rigide les efforts de friction développés par le rail sur la partie du monobloc unique en contact avec le rail.16.- electromagnetic shoe according to one of claims 8 to 15, characterized in that the continuous central strip of non-magnetic material (s) of the single piece is provided with teeth and / or projections capable of cooperating with teeth and / or conjugate projections formed on a rigid envelope of the excitation coil in order to transmit to this rigid envelope the friction forces developed by the rail on the part of the single piece in contact with the rail.
EP81400963A 1980-06-20 1981-06-16 Electromagnetic skid Withdrawn EP0042787A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE883950 1980-06-20
BE883950 1980-06-20

Publications (1)

Publication Number Publication Date
EP0042787A1 true EP0042787A1 (en) 1981-12-30

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Application Number Title Priority Date Filing Date
EP81400963A Withdrawn EP0042787A1 (en) 1980-06-20 1981-06-16 Electromagnetic skid

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EP (1) EP0042787A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0633174A1 (en) * 1993-07-05 1995-01-11 Siemens Aktiengesellschaft Österreich Magnetic track brake
DE19619409A1 (en) * 1996-05-14 1997-11-27 Ruefas Pagid Ag Rail vehicle magnetic rail-brake
CN105151077A (en) * 2015-08-21 2015-12-16 青岛四方车辆研究所有限公司 Rail transit magnetic track brake provided with horizontal magnet exciting coils

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK8717C (en) * 1906-08-06 Westinghouse Electric Corp Device for magnetic brakes for railway wagons and other wagons.
US2207151A (en) * 1937-08-11 1940-07-09 Transit Res Corp Brake shoe
FR1010184A (en) * 1950-01-21 1952-06-09 Method of increasing the adhesion of vehicles on rails and devices by allowing the implementation
DE843930C (en) * 1948-11-04 1952-07-14 Freins Jourdain Monneret Soc Electromagnet for the transmission of torque or thrust between the magnet body and the armature
DE1802876A1 (en) * 1968-10-12 1970-06-04 Bielefelder Elektrotechnische Electromagnetic rail brake
FR2409897A1 (en) * 1977-11-23 1979-06-22 Wabco Westinghouse Spa ELECTROMAGNETIC SKATES, ESPECIALLY FOR RAILWAY VEHICLES

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK8717C (en) * 1906-08-06 Westinghouse Electric Corp Device for magnetic brakes for railway wagons and other wagons.
US2207151A (en) * 1937-08-11 1940-07-09 Transit Res Corp Brake shoe
DE843930C (en) * 1948-11-04 1952-07-14 Freins Jourdain Monneret Soc Electromagnet for the transmission of torque or thrust between the magnet body and the armature
FR1010184A (en) * 1950-01-21 1952-06-09 Method of increasing the adhesion of vehicles on rails and devices by allowing the implementation
DE1802876A1 (en) * 1968-10-12 1970-06-04 Bielefelder Elektrotechnische Electromagnetic rail brake
FR2409897A1 (en) * 1977-11-23 1979-06-22 Wabco Westinghouse Spa ELECTROMAGNETIC SKATES, ESPECIALLY FOR RAILWAY VEHICLES

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0633174A1 (en) * 1993-07-05 1995-01-11 Siemens Aktiengesellschaft Österreich Magnetic track brake
DE19619409A1 (en) * 1996-05-14 1997-11-27 Ruefas Pagid Ag Rail vehicle magnetic rail-brake
DE19619409C2 (en) * 1996-05-14 2001-02-15 Ruefas Pagid Ag Magnetic rail brake
CN105151077A (en) * 2015-08-21 2015-12-16 青岛四方车辆研究所有限公司 Rail transit magnetic track brake provided with horizontal magnet exciting coils

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