BE1020567A3 - CURRENT RETURN DEVICE FOR RAILWAY VEHICLES. - Google Patents

Description

CURRENT RETURN DEVICE FOR VEHICLES

Railway stations, railway

The present invention relates to a current return device arranged to be enclosed in a railway vehicle bogie provided with at least one axle supporting a wheel on each of its ends, each wheel comprising a hub, a front face and a face. linked, each bonded face being connected to an end of said axle, said device comprising: a) at least one contact disk comprising at least one conductive material, b) at least one blade comprising at least one conductive material, in contact with said disk c) a support comprising at least one insulating material connected to a fixing means comprising at least one conductive material and arranged to secure said support to a railway vehicle bogie, to which said axle is fixed, said support being provided to support said contact disc, located on the opposite side of the wheel, and allowing said contact disc or said broom to be joined to said means of conductive fixing, d) a connection piece comprising at least one conductive material and integrally connecting to said front face of the wheel to said blade, said blade optionally being integrally connected to a brush holder.

Such a current return device is known from the state of the art and comprises a fixing means which is for example a metal rod, preferably a transition metal or their alloy, in extension of the ends of a axle and integral with the bogie of the railway vehicle, and a portion of rod through the wheel at its center by its hub. The support made of an insulating material, which comprises a front face and a dorsal face, is traversed by a portion of the rod. The front face of said support is extended by two nozzles provided to engage a contact disc connected to said rod, such that said contact disc is disposed protruding over the bussels and located on the opposite side to the wheel. A face of the contact disc is thus integrally bonded to the front face of said support with the aid of a spacer. The stability of said protruding contact disc is provided by resilient bushings located between the bushings of said support and the back face of said contact disc. The device comprises on the one hand an aluminum brush holder provided with a removable metal-graphite brush, and on the other hand a conductive connection piece in the form of an aluminum enclosure defining a closed cavity of one side by said wheel and the other by said brush holder so that the blade is in contact with said contact disk.

This current return device, known from the state of the art, is particularly intended to be enclosed in a tramway bogie whose platform is lowered and which comprises at least one axle-bridge supporting a wheel on each of its ends. Said bogie comprises an access path to said current return device whose bore is smaller than that of the opening in which said brush holder is fitted.

As the rail vehicle moves, a current is generated at the power supply equipment and tends to reach the earth via a preferred path. More specifically, this return current typically follows a path that passes through the wheel and its bearings to the rails and the ground. Such a path is problematic in that it induces the production of arcing between the wheel and the rolling system, which are detrimental to the proper functioning of the latter. The current feedback device is therefore used in railway vehicles to deflect the return current from their preferred path, from the power supply to earth, avoiding the rolling system. For the return current to follow the path well defined by the current feedback device, it is essential that the latter includes materials of lower electrical resistivity than those comprising the wheel and its rolling system. As a result, the return current passing through the wheel to reach the earth is deflected by the conductive connecting piece, by the brush which directs the current towards the contact disc, and finally by the rod which is connected to the ground via the wheel by electrical discharge wiring.

In operation, in the known device, the brush, secured to the wheel by the aluminum enclosure is driven by the wheel and rubs against the front surface of the contact disc which is fixed when it is secured to the bogie. This friction is on the one hand the cause of the wear of the brush and the front surface of the contact disc, and on the other hand generates a large amount of dust detrimental to the proper functioning of the rolling system. These dusts are therefore contained in the cavity of the aluminum enclosure by baffles. However, the wear dust accumulated in said cavity pollutes the contact disc and the blade and results in a poorer electrical contact between these two parts and therefore a less efficient operation of the current return device. In order to reduce the accumulation of large amounts of wear dust in the cavity, said cavity has been separated in two by the introduction of a seal placed between the front surface of the contact disc and the wall internal speaker at the junction broom-contact disc.

Regular cleaning of this cavity, the brush and the surface of the contact disc is therefore essential to ensure the efficiency of the current return device. Access to the cavity is provided by removing the brush holder nested in said enclosure. In this context, the contact disc is arranged protruding to facilitate the cleaning of the front surface of the disc thus making it closer to said opening in which is fitted said brush holder.

Unfortunately, the contact disc as described in the prior art has a low resistance to shock and vibration, despite the presence of elastic bearings located between the bushings of said support and said contact disc. Indeed, in operation, the wheels of the tram are strongly stressed, whether at each passage of a rail portion to another, when the course has a curved section, or during the braking and acceleration phases of the tram.

In addition, the accumulation of dust at the pads has the effect of altering their elastic properties. This results in a decrease in the resistance of said contact disc to shocks and vibrations. On the other hand, the resilient bushings furthermore make it possible to generate a voltage between said brush and said contact disk. This tension makes it possible to keep a frank contact between the surface of said disk and that of said blade as it wears. The alteration of the elastic properties of the bushings no longer makes it possible to compensate for losses of material at the level of the blade, and this results in less good contact between the surface of the contact disc and the blade, and therefore a less good electrical contact which compromises the efficiency of the current return device.

Stabilizers, integral with said support, have therefore been added in some existing versions to the device in order to improve the resistance of the contact disc to shocks and vibrations intrinsic to the operation of the tram, making de facto the complex construction device.

The contact disc, like the broom, wears out and needs to be replaced regularly. Access to the current return device is provided by said access path of the bogie and once the brush holder removed, the blade can then be dissociated from the brush holder and replaced. Also, the fastening means may, due to the various constraints inherent in the putting into circulation of the railway vehicle, break and in which case it must be replaced.

With regard to the contact disk and the fixing means, their replacement requires the removal of the stabilizers and the seal that can not be achieved without dismantling the aluminum enclosure and therefore at least a part of the bogie.

The disassembly and reassembly operation of said at least a portion of the bogie and the aluminum enclosure, followed by the step of replacing said contact disk is at least 16 hours. Given that a tramway includes at least four current return devices, the total duration of an interview is estimated at more than two days, during which time the tramway is immobilized. This immobilization for such a long period is expensive and seriously compromises the economic viability of the vehicle, especially given the frequency of replacement and the multiplication of vehicles in a fleet of a city.

The invention aims to overcome the drawbacks of the state of the art by providing a simpler and more compact construction current return device, and allowing disassembly and rapid replacement of the contact disc. - v-

To solve this problem, it is provided according to the invention, a device as indicated at the beginning in which said support comprises a cavity arranged to accommodate said contact disk.

In this way, the contact disc is stabilized by the cavity of the support and the current return device according to the present invention is of simplified construction by making it possible to overcome the presence of the stabilizers.

In addition the space that was necessary to place the stabilizers is therefore replaced by a dust retention zone, in the extension of the cavity of said support, by a double baffled system, making obsolete the use of the retention joint.

Surprisingly, the presence of a cavity in the support for accommodating said contact disk not only simplifies the construction of the current return device but also the disassembly and replacement of said contact disc exclusively by the way. access of the bogie, since the device according to the invention no longer includes the stabilizers and the seal. In this way, it eliminates the dismantling step of the aluminum enclosure and therefore a portion of the bogie, which can significantly reduce the maintenance time of the current return device of about 16 hours to about 1 hour.

Moreover, the fact that the contact disc is housed in the cavity of said support contributes to improving the stability and the resistance to shocks and vibrations, a large part of which is absorbed by said outer casing, and thus to increase its duration. life.

In an advantageous variant according to the present invention, said fixing means is mounted in an outer casing comprising at least one rigid insulating material.

The major advantage of this variant according to the invention lies in the fact that the vibration resistance of said fixing means is increased while not impairing its ability to conduct the current.

In a particular embodiment, a portion of said outer casing is integrally connected to said contact disk and is arranged to pass through said support.

In this particular arrangement, said outer envelope acts as a guide, which facilitates the step of replacing said contact disc by the access path of the bogie and reduce the duration of maintenance of said return device of current.

Advantageously, said blade is integrally connected to a brush holder by a lug fixing system, so that said blade can be easily removed from its brush holder and replaced more easily.

In an advantageous variant, said conductive connection piece is an enclosure defining a cavity which includes the contact disc, its support and the brush, and which comprises a first and a second cavity portion, said enclosure being closed on one side by the wheel and on the other side by said brush holder. Said first cavity is arranged to house the brush holder and the brush while said second portion of said cavity is a wear dust retention zone which takes the form of a double baffled system.

In this way, the broom and its brush holder are stabilized by said first cavity while the second not only allows to retain the wear dust and thus preserve the bearings of the wheel but also to store the dust sufficiently far from the junction between the blade and the disk, so that these dusts do not pollute the device and that the good electrical contact between said blade and said contact disk is guaranteed.

In addition, the use of a closed enclosure as a conductive connecting part de facto implies that said portion of said fastening means and said outer casing portion are arranged to pass through the wheel at its center through the hub.

This particular embodiment makes it possible for said fixing means not to come into contact with said closed enclosure.

Advantageously, the brush holder comprises at least one elastic material such as a spring.

The use of a brush holder with elastic properties makes it possible to generate a tension between said brush and said contact disk. This tension ensures a frank contact between the surface of said disk and that of said blade as it wears.

Preferably, said contact disc comprises at least one metal material such as bronze.

In the current return device according to the invention, the support comprises an electrically insulating material, preferably a dielectric material selected from the group consisting of epoxidized polymers and glass fibers, for example impregnated and their combination.

Advantageously, said broom comprises metal-graphite while the connecting piece comprises at least one metallic material such as aluminum.

Other embodiments of said current return device according to the invention will become apparent from the appended claims.

The invention also relates to a method of dismounting a current feedback device enclosed in a bogie comprising the following steps: a) access to a gripping means provided on a brush or a brush holder of said return device current through a front access path of said bogie, b) disassembly of said brush, possibly integrally connected to said brush holder, of the current return device, with the aid of a gripping means.

Said disassembly method further comprises a step in which said brush is disengaged from its brush holder, and a step wherein said contact disc is disassembled from said current return device by means of a gripping means.

In addition, the invention relates to a method of mounting a current feedback device enclosed in a bogie comprising the following steps: a) supplying a brush, possibly integral with a brush holder of a device current return by a front access path of said bogie, b) an assembly of said brush, possibly integrally connected to said brush holder, on a contact disc with the aid of a gripping means.

This method of mounting a current return device enclosed in a bogie according to comprises firstly a step in which said blade is secured to said brush holder prior to said mounting step, and secondly a mounting step of a contact disc on a support by means of a gripping means.

Other embodiments of the methods according to the invention will become apparent from the appended claims.

Other features, details and advantages of the invention will emerge from the description given below, without limitation and with reference to the appended drawings:

Figure 1 is a schematic top view of a portion of a railway vehicle bogie with two axles each supporting two wheels.

Figure 2 is a schematic longitudinal sectional view of an axle and a portion of the bogie in which is locked the device according to the invention.

Figure 3 is a schematic longitudinal sectional view of the device according to the invention.

FIGS. 4a and 4b illustrate the steps of the method in longitudinal section of the disassembly of the current return device, in which the brush as well as the brush holder and the contact disk are subtracted from the rest of the device, and respectively in which the brush , the brush holder and the contact disc are subtracted from the rest of the device.

FIG. 1 is a schematic top view of a part of a railway vehicle bogie 1 provided with two axles 2 each supporting two wheels 3 on the ends, each wheel comprising a hub 4, a front face 5 and a bound face 6, the latter being connected to the end of the axle. The current return device 7 is placed in said bogie portion which includes a front access channel 8 to said current return device.

When the railway vehicle moves on the rails R, the current generated at the power supply equipment tends to reach the rails R and then the ground via the wheels 3 and their rolling system.

In order to prevent the current from passing through the wheel and the bearings, and thus generating electric arcs, the current is deflected from the wheel and its bearings by said current return device 7.

Figure 2 is a schematic longitudinal sectional view of an axle and a portion of the bogie in which is locked the device according to the invention, while Figure 3 illustrates a schematic longitudinal sectional view of said device.

As shown in FIG. 2, the current return device according to the invention comprises a fastening means 9, which is, for example, a rod comprising at least one conductive material, extending from the ends 10 of an axle 2, by example a bridge axle as shown in Figure 2, and which is secured to said bogie 11 by said bridge axle 2, and a portion through which the wheel 3 at its center by its hub 4. Said bogie 11 is arranged to receive the platform on which is erected the passenger compartment of said railway vehicle.

As can be seen in Figure 3, the current feedback device further comprises an insulating support 12a, 12b connected to said fixing means which secures said support to said bogie 11. Said support comprises a cavity arranged to accommodate at least one disk 13, located on the side opposite the wheel, and to allow the latter to be in contact with said fixing means.

In this way, the contact disc is stabilized by the cavity of the support and the current return device according to the present invention is of more simplified construction than that of the device as described in the prior art.

Furthermore, the current feedback device comprises firstly a brush holder 14 which is conductive and provided with at least one removable conductive brush 15 and a gripping means 22, and secondly a conductive connection piece. 16 which for example takes the form of an enclosure defining a cavity closed on one side by said front face 5 of said wheel and on the other side by said brush holder 14 or said blade 15 so that the latter is in contact with said contact disc. The conductive broom 15 is enclosed in a first cavity 19 of said conducting enclosure 16.

In the particular embodiment of the invention as illustrated in FIG. 3, said fastening means 9 is a threaded rod whose said portion, which is arranged to obstruct an orifice, possibly provided with a thread, present on said contact disc, constitutes a connection means for connecting preferably preferably said contact disc to said threaded rod for example by aiming at said rod portion.

In addition, said threaded rod is mounted in an insulating outer casing 17 which takes for example the shape of a rigid tubular and of which a part, which is arranged to obstruct said orifice present on the contact disc and to pass through an orifice present on said support 12a, 12b is a connecting means for connecting preferably rigid tube rigidly to said contact disc.

Finally, in the particular embodiment of the invention, said portion of the tubing and said portion of the rod pass through the wheel at its center by its hub.

The current return device according to the invention makes it possible to divert this current towards the earth by the conductive connection piece 16, by the brush 15 which directs the current towards the contact disk 13, and finally by the fixing means 9 which is connected to the rails via the wheels 3 by electrical wiring.

In operation, in the device according to the invention, the blade 15, locked in said first cavity portion 19 of said conducting enclosure 16 is driven and rotated by the wheel 3 to which it is secured and rubs against the disk of contact 13 which is fixed when it is secured to the bogie 11 by the fastening means 9. This continuous friction wears the surfaces of said contact disc and said brush, and is accompanied by a release of wear dust which accumulate in the retention zone formed in said second cavity portion 20. Due to its double-baffled shape, said retention zone makes it possible to store the wear dust at a distance from the interface between the blade and the blade. contact.

As shown in FIG. 4a, said blade is preferably integrally connected to said brush holder by a lug fixation system 18.

Said cavity defined by the conductive connection piece which takes the form of a closed enclosure 16, is illustrated in Figure 4b.

As shown in this figure, said cavity is intended to include said support and said contact disk as well as said brush, and comprises a first cavity portion 19 and a second cavity portion 20.

Said first cavity portion 19 is arranged to accommodate said brush alone or with said brush holder while the second cavity portion 20 is a wear dust retention zone produced during the friction of said brush on said contact disc. Preferably, said retention zone is a double-baffled system.

By way of illustration, FIGS. 4a and 4b also summarize the major steps in the maintenance process of said current feedback device. This replacement process involves a disassembly method and a method of mounting said current device.

The disassembly method comprises a step of access by said front access channel 8 to said gripping means 22 provided on the brush 15 or the brush holder 14 of said current return device, and a step of disassembly of said brush, possibly connected to the brush holder, with the aid of said gripping means, as illustrated in FIG. 4a. In Figure 4a, the disassembly step of the blade and possibly the brush holder is illustrated by the arrow pointing to the right. For example, the gripping means is a key disposed projecting on said blade, or possibly said brush holder, said key comprising a threaded rod complementary to a thread of an orifice of said blade, or possibly said brush holder, in which it is intended to be aimed. Preferably, the threaded rod of said key is mounted in a tube whose one end is intended to fit on a connection piece arranged in a projection on said blade, or possibly said brush holder, when said threaded rod of said key is screwed into the thread of said broom or said brush holder.

The disassembly method further comprises a step in which said brush is disengaged from its brush holder for example, by separating said brush holder from the lug fixing system and disengaging the blade lug broom, followed by a step wherein said contact disk is disassembled, as shown in Figure 4b by the arrow pointing to the right figure 4b, of said current return device by means of a gripping means 23, for example by unscrewing it the threaded rod, which is dislodged from said cavity 21 of said support.

Once disassembled, said current return device is for example cleaned of wear dust and optionally, said brush and said contact disc are replaced.

The mounting method of said current return device comprises a first step of supplying said brush, possibly integral with said brush holder, by said front access channel 8 followed by a step of mounting said brush on said contact disc in connecting said brush or said brush holder to said connection piece by means of said gripping means 22. In FIG. 4a, the step of dismounting the brush and possibly the brush holder is illustrated by the arrow pointing to the left. .

Said method of mounting said current return device further comprises a step, preceding the step of mounting said brush on said contact disc, wherein said brush is secured to said brush holder.

The step of mounting said blade on the contact disk may be preceded by a step of mounting the contact disk on said support of the current return device. In Figure 4b, the mounting step of the contact disc on the support is illustrated by the arrow pointing to the left.

In the particular embodiment as described in Figures 4a and 4b, said outer casing 9 acts as a guide, which facilitates the process of replacing said contact disc.

The present invention also relates to the particular or alternative embodiment of said current feedback device, as described above, wherein said brush and possibly said brush holder are housed in the cavity of said support and said contact disc is connected to said conductive connection piece.

In this context, the invention, in another alternative embodiment, relates to a current return device in which said blade is arranged to be housed in said cavity of said support and to be connected to said fixing means, and wherein said contact disc is intended to be connected to said conductive connection piece.

Therefore, said enclosure is closed on one side by said front face of said wheel and on the other side by said contact disc, said first portion of said cavity being arranged to accommodate said contact disc.

In this current return device, said fixing means is a threaded rod whose said part, which is arranged to obstruct an orifice, possibly provided with a screw thread, present on said brush, constitutes a connecting means for connecting preferably solidly said brush to said threaded rod for example by targeting the latter to said rod portion.

In addition, said threaded rod is mounted in an insulating outer casing which takes for example the shape of a rigid tubular and a part of which is arranged to obstruct said orifice present on said brush and to pass through an orifice present on said support, is a connection means for connecting preferably rigid tube rigidly said brush.

Also, the subject of the invention is an alternative method of disassembling a current return device of a bogie from the frontal access way 8 of said bogie which makes it possible to reach a gripping means 22 provided on a contact disc 13 of said current return device, said gripping means 22 for disassembling said contact disc from said current return device.

Said alternative disassembly method further comprises a step of disassembly of the blade 15, possibly integrally connected to said brush holder 14, which is followed by a step in which said blade is disengaged from the brush holder.

Finally, the invention provides an alternative method of mounting a current feedback device of a bogie comprising a first step of feeding a contact disc 13 of a current return device by a path of front access 8 followed by a mounting step of said contact disk on the brush of said current return device.

Said alternative mounting method further comprises a step of mounting the blade 15 on a support of the current return device, prior to said mounting step of said contact disk, said step of mounting the blade optionally being preceded by a step in which blade is secured to the brush holder.

It is understood that the present invention is in no way limited to the above embodiments and that many modifications can be made without departing from the scope of the appended claims.

Claims (15)

1. Current return device (7) arranged to be enclosed in a bogie (1) of railway vehicles provided with at least one axle (2) supporting a wheel (3) on each of its ends, each wheel comprising a hub (4), a front face (5) and a bonded face (6), each bonded face being arranged to be connected to an end of said axle, said device comprising: a) at least one contact disc (13) comprising at least a conductive material, b) at least one broom (15) comprising at least one conductive material, in contact with said contact disc (13) c) a support (12a, 12b) comprising at least one insulating material intended to be connected to fastening means (9) comprising at least one conductive material and arranged to secure said support to a railway vehicle bogie, to which said axle is fixed, said support being provided to support said contact disc, situated on the opposite side to the wheel , and allow said that contact to be joined integrally or not to said conductive fixing means, d) a connecting piece (16) comprising at least one conductive material and integrally connecting to said front face of the wheel (3) to said brush (15), said brush being optionally integrally connected to a brush holder (14). characterized in that said support comprises a cavity (21) arranged to accommodate said contact disk. 2. current feedback device according to claim 1, wherein the blade, or possibly the brush holder, comprises a gripping means (22). A current feedback device according to claim 1 or claim 2, wherein the contact disk comprises gripping means (23). 4. Current feedback device according to any one of claims 1 to 3, wherein said fixing means (9) is mounted in an outer casing (17) comprising at least one rigid insulating material. 5. A current feedback device according to claim 4, wherein said outer casing (17) comprises means for connection with said contact disc (13), arranged to secure or not said contact disc to said outer casing. 6. current feedback device according to any one of the preceding claims, wherein said connection means of said outer casing is a projection arranged to pass through an orifice on said support. The current feedback device according to any one of the preceding claims, wherein said brush is integrally connected to said brush holder by a pod attachment system (18). A current feedback device according to any one of the preceding claims, wherein said conductive connecting piece (16) is an enclosure defining a cavity, said cavity comprising a first (19) and a second cavity portion (20) said enclosure being closed on one side by said front face (5) of said wheel (3) and on the other side by said brush (15) or said brush holder (14), said first part of said cavity (19) being arranged to house said brush or said brush and said brush holder, said second portion of said cavity (20) being intended to accommodate a wear dust retention zone. The current feedback device of claim 8, wherein said dust retention zone is a double baffled system. 10. A method of dismounting a current return device enclosed in a bogie comprising the following steps: c) an access to a gripping means (22) provided on a brush (15) or a brush holder (14) of said current return device by a frontal access way (8) of said bogie (1), d) disassembly of said brush (15), possibly integrally connected to said brush holder (14), of the current return device, to using a means of grip. 11. A method of dismounting a current return device enclosed in a bogie according to claim 10, wherein said blade is further separated from said brush holder. 12. A method of dismounting a current feedback device enclosed in a bogie according to claim 11 or claim 10, further comprising a step of dismounting a contact disk using a gripping means ( 23). 13. A method of mounting a current feedback device enclosed in a bogie comprising the following steps: c) supplying a brush, possibly integral with a brush holder of a current return device by a d frontal access (8) of said bogie (1), d) an assembly of said brush (15), possibly integrally connected to said brush holder (14), on a contact disc by means of a gripping means. 14. A method of mounting a current feedback device enclosed in a bogie according to claim 13, wherein said blade is secured to a brush holder prior to said mounting step. 15. A method of mounting a current feedback device enclosed in a bogie according to claim 14 or claim 13, further comprising a step of mounting a contact disk on a support using a means. grasping.