EP1508455B1 - Method for protecting an axle of a railway vehicle, corresponding axle, and bogie with such an axle. - Google Patents

Abstract

The procedure for protecting a railway vehicle bogie axle (6) consists of rolling a strip (10) of a supple polymer material cut from a large sheet and having a preferable thickness of 8 - 10 mm round each of the axle zones (2) to be protected and fixing it in place. The two ends (10 1, 10 2) of each strip are chamfered, and grooves (12) are made in its inner surface. The strips are held in place by mechanical means, e.g. stainless steel collars.

Description

The present invention relates to a method for protecting a rail vehicle axle, a railway vehicle axle thus produced, and a railway vehicle bogie comprising at least one such axle.

Conventionally, railway vehicles are equipped with wheels, which are most often mounted in pairs, on respective axles. In service, there is a risk of stones being thrown from the ballast to the axles, which can cause cracks. The size of the latter is able to progress, to cause a rupture of the entire axle.

This implies that it is not possible to rely on a traditional fatigue analysis with regard to the axles, but that it is necessary to carry out frequent inspections of these, in order to detect possible cracks. However, it is desirable to reduce the number of such visual inspections to the extent possible given the cost and time involved.

For this purpose, it has been proposed various methods to protect the axles against ballast projections.

A first solution is to project polyurethane, so as to form a peripheral coating around the axle. This implies, however, a high manufacturing cost. Moreover, once the coating is put in place, it is no longer possible to directly detect any superficial defects present at this axle.

As an alternative, it has been proposed to coat the axle with different fabrics. However, they tend to shred under the action combined humidity, axle rotation and impacts.

Finally, WO-A-00/59764 teaches to place, around the axle, shells molded and then machined, which are based on polymer. This last solution proves to be expensive since, for each diameter and each axle length to be protected, it is necessary to count with a specific mold, as well as with a suitable machining.

That being said, the invention aims to remedy the various disadvantages of the prior art mentioned above.

• on fournit au moins une bande souple réalisée en un matériau polymère ;
• on enroule la ou chaque bande autour de la ou de chaque région de l'essieu devant être protégée ;
• on fixe la ou chaque bande, ainsi enroulée, par rapport à l'essieu

caractérisé en ce qu'il comporte une étape supplémentaire consistant à réaliser des biseaux sur des extrémités de la ou chaque bande, de manière à délimiter deux faces biseautées destinées à venir en contact mutuel.For this purpose, it relates to a method for protecting a rail vehicle axle, especially with regard to projections of the ballast, comprising the following steps:

• at least one flexible strip made of a polymeric material is provided;
• winding the or each band around the or each region of the axle to be protected;
• the one or each band, thus wound, is fixed with respect to the axle

characterized in that it comprises an additional step of making bevels on ends of the or each strip, so as to define two bevelled faces intended to come into contact with each other.

• on forme la ou chaque bande à partir d'une plaque de plus grandes dimensions ;
• le matériau polymère est un polyuréthane ;
• le matériau polymère présente une dureté comprise entre 80 et 110 Shore A, de préférence entre 90 et 100 Shore A, notamment voisine de 95 Shore A ;
• la ou chaque bande présente une épaisseur comprise entre 5 et 15 mm, de préférence entre 8 et 10 mm ;
• on réalise des moyens d'amorce de pliage dans la ou chaque bande, en particulier plusieurs rainures ou plusieurs gorges ;
• on fixe la ou chaque bande, par rapport à l'essieu, au moyen d'au moins un organe de maintien mécanique.

According to other features of the invention:

• forming the or each band from a plate of larger dimensions;
• the polymeric material is a polyurethane;
• the polymeric material has a hardness of between 80 and 110 Shore A, preferably between 90 and 100 Shore A, in particular around 95 Shore A;
• the or each strip has a thickness of between 5 and 15 mm, preferably between 8 and 10 mm;
• fold initiation means are provided in the or each strip, in particular several grooves or grooves;
• the or each band is fixed with respect to the axle by means of at least one mechanical holding member.

The invention also relates to a railway vehicle axle, intended to connect at least two wheels of said vehicle, provided with at least one flexible protective strip made of a polymer material, the or each strip being wound around a region corresponding axle to be protected, in particular with regard to projections of the ballast, and for which there is further provided means for fixing the or each strip relative to the axle, characterized in that the or each strip is provided at its longitudinal ends with two beveled faces which are in mutual contact.

• l'essieu est pourvu d'au moins un organe auxiliaire, en particulier au moins un disque de freinage, délimitant plusieurs régions à protéger, s'étendant entre le ou chaque organe auxiliaire et/ou les roues, alors qu'il est prévu plusieurs bandes de protection, dont chacune s'étend autour d'une région correspondante ;
• le matériau polymère est un polyuréthane ;
• le matériau polymère présente une dureté comprise entre 80 et 110 Shore A, de préférence entre 90 et 100 Shore A, notamment voisine de 95 Shore A ;
• la ou chaque bande présente une épaisseur comprise entre 5 et 15 mm, de préférence entre 8 et 10 mm ;
• la ou chaque bande est pourvue de moyens d'amorce de pliage, en particulier de plusieurs rainures ou de plusieurs gorges ;
• les moyens de fixation de la ou chaque bande par rapport à l'essieu, comprennent au moins un organe de maintien mécanique.

According to other features of the invention:

• the axle is provided with at least one auxiliary member, in particular at least one braking disk, delimiting several regions to be protected, extending between the or each auxiliary member and / or the wheels, whereas several protective strips, each of which extends around a corresponding region;
• the polymeric material is a polyurethane;
• the polymeric material has a hardness of between 80 and 110 Shore A, preferably between 90 and 100 Shore A, in particular around 95 Shore A;
• the or each strip has a thickness of between 5 and 15 mm, preferably between 8 and 10 mm;
• the or each band is provided with folding initiation means, in particular of several grooves or of several grooves;
• the fastening means of the or each band relative to the axle comprise at least one mechanical holding member.

The invention finally relates to a railway vehicle bogie, comprising several axles, each of which connects at least two wheels, characterized in that each axle is as defined above.

• la figure 1 est une vue de face, illustrant un essieu de véhicule ferroviaire, ainsi qu'une première variante de réalisation d'une bande destinée à sa protection ;
• la figure 2 est une vue en coupe, selon la ligne II-II à la figure 1, illustrant à plus grande échelle une rainure ménagée sur la bande de la figure 1 ;
• la figure 2A est une vue en coupe, analogue à la figure 2, illustrant à plus grande échelle une gorge ménagée sur une bande de protection conforme à une seconde variante de réalisation de l'invention ;
• les figures 3 et 3A sont des vues de côté illustrant une étape du procédé de protection des essieux, au moyen respectivement des bandes des figures 2 et 2A ;
• les figures 4 et 4A sont des vues de côté, analogues aux figures 3 et 3A, illustrant les essieux protégés au moyen respectivement des bandes des figures 2 et 2A ;
• la figure 5 est une vue de face, analogue à la figure 1, illustrant un essieu protégé conformément à l'invention ; et
• la figure 6 est une vue de face, analogue aux figures 1 et 5, illustrant une autre variante de réalisation de l'invention.

The invention will be described below, with reference to the accompanying drawings, given solely by way of non-limiting examples, in which:

• the figure 1 is a front view, illustrating a rail vehicle axle, and a first embodiment of a strip for its protection;
• the figure 2 is a sectional view taken on line II-II to figure 1 , illustrating on a larger scale a groove on the belt of the figure 1 ;
• the Figure 2A is a sectional view, similar to the figure 2 , illustrating on a larger scale a groove on a protective strip according to a second embodiment of the invention;
• the Figures 3 and 3A are side views illustrating a step of the axle protection process, respectively by means of Figures 2 and 2A ;
• the Figures 4 and 4A are side views, similar to Figures 3 and 3A , illustrating the protected axles by means respectively of the strips of Figures 2 and 2A ;
• the figure 5 is a front view, similar to the figure 1 illustrating a protected axle according to the invention; and
• the figure 6 is a front view, similar to figures 1 and 5 , illustrating another alternative embodiment of the invention.

The figure 1 illustrates an axle 2, of known type, which interconnects two wheels 4 belonging to a railway vehicle bogie, not shown. This axle 2 comprises in known manner a cylindrical main rod 6, which is connected to the wheels 4 by peripheral shoulders 8.

The figure 1 illustrates also a strip 10, intended to cover the outer periphery of the axle 2. This strip is made of a plastic material, such as polyurethane. It has a hardness of between 80 and 110 Shore A, preferably between 90 and 100 Shore A, in particular around 95 Shore A.

The constituent material of this band 10 may advantageously have other remarkable characteristics. Thus, it can in particular be moldable plate, and be machinable.

The thickness e of this band, referenced in particular on the figure 3 , is advantageously between 8 and 10 mm. Moreover, its length corresponds to the width of the axle 2, while the width of this band corresponds to the perimeter of this axle.

This band 10 is cut advantageously from a plate, not shown, having larger dimensions. As shown in figure 2 grooves 12 are formed laterally in this band, once the latter has optionally been cut.

These grooves, whose faces extend at 45 ° relative to an axis perpendicular to its main surface, facilitate the winding of this band.

Moreover, as shown in particular figure 3 , the longitudinal ends of the strip 10 are bevelled, so as to form two end faces 10 ₁ and 10 ₂ . As illustrated on this figure 3 it is a matter of winding the band 10 around the axle 2, which is facilitated by the presence of the grooves 12.

Once this strip 10 is wound, as shown in FIG. figure 4 the bevelled faces 10 ₁ and 10 ₂ come into mutual contact. Such a measure is advantageous, since it makes it possible in particular to reduce unbalance at the axle.

Then, there is reported at least one mechanical holding member 14, of a type known per se, around the band 10, itself arranged at the periphery of the axle. This is also illustrated in figures 4 and 5 where three members 14 are provided.

Such a holding member is for example a metal link, especially stainless steel, or a self-tightening collar. However, it should be noted that it is also possible to bond each other, by gluing, the strip 10 and the rod 6 of the axle 2.

The figure 5 illustrates, seen from the front, the axle 2 covered by the belt 10. It may be noted that this band 10 is provided with lateral shoulders 11, extending in the vicinity of those 8 of the axle 2, so as to maintain substantially constant the thickness e of this band.

Alternatively, the fold initiation grooves 12 may be replaced by equivalent embodiments, such as grooves. These grooves or grooves may be present on the inside or outside of the strip.

One of these possibilities is more particularly illustrated in Figures 2A to 4A . In these figures, the mechanical elements similar to those of Figures 2 to 4 receive the same number, assigned the reference "premium".

As shown more particularly in Figure 2A , the grooves 12 'are formed laterally in the strip 10', once the latter has been optionally cut. The radius of curvature r of each groove is for example advantageously between 3 and 5 mm, while its depth is for example close to half the thickness of the strip 10 '.

In this variant, as illustrated in Figures 3A and 4A the strip 10 'is wound so that the grooves 12' are present on the outer face of this strip. The mechanical maintenance of this strip relative to the axle is finally achieved in a manner similar to that described with reference to the figures 4 and 5 .

The figure 6 illustrates an alternative embodiment of the invention. In this figure, the mechanical elements similar to those of the preceding figures are assigned the same reference numbers, increased by 100.

There is an axle 102, connecting two wheels 104. This axle differs from that 2 of the preceding figures, in that it is also provided with brake disks 105, mounted in conventional manner on the rod 106.

In this case, for the protection of the axle, it is to have three strips 110A, 110B and 110C around the respective three regions 102A, 102B and 102C, respectively defined by the wheels 104 and the discs 105.

These strips 110A, 110B, 110C are similar to that 10, of larger size, of the preceding figures. Moreover, the assembly of these three bands, around Corresponding regions 102A to 102C are operated in the same manner as described above.

Of course, by way of variant not shown, the three strips 110A, 110B and 110C can be replaced by strips similar to that of Figures 2A to 4A . In this respect, these strips are provided, on their outer face, fold initiation grooves, while having transverse dimensions smaller than those of the aforementioned strip 10 '.

If it is desired to carry out a visual inspection of the outer surface of the axle 2, 2 'or 102, it is a matter of removing the or each strip 10, 10' or 110A, 110B and 110C. For this purpose, the mechanical holding member 14 is removed successively, for example by cutting it, then the or each strip initially wound around the axle.

The invention makes it possible to achieve the objectives mentioned above.

Indeed, the or each protective band can be implemented simply and quickly, around the axle, without the need to use specific tools. Moreover, the disassembly of the band is effected easily, by removing the mechanical holding member.

In addition, the solution provided by the invention proves to be considerably less expensive than that described in WO-A-00/59764 , where it is especially necessary to use a specific mold. Indeed, the invention allows to use plastic bands of simple structure, the cost is relatively low. This is particularly remarkable in the case where these strips are obtained from plates of larger dimensions.

Claims (15)

1. Process for protecting a railway vehicle axle (2; 2'; 102), particularly with respect to ballast thrown upwards, comprising the following stages:

   - at least one flexible strip (10; 10 ; 110A, 110B, 110C), made of a polymeric material, is supplied,

   - the or each strip (10, 10', 110A, 110B and 110C) is wrapped round the or each area (2; 2'; 102A, 102B, 102C) of the axle to be protected and

   - the or each strip, thus wrapped round, is fastened with respect to the axle,

   characterized in that it comprises a supplementary stage consisting of forming chamfers on ends of the or each strip (10; 10'; 110A, 110B, 110C), so as to define two chamfered faces (10₁, 10₂; 10'₁, 10'₂) intended to come into contact with each other.
2. Process according to claim 1, characterized in that the or each strip (10; 10'; 110A, 110B, 110C) is formed from a sheet of larger dimensions.
3. Process according to claim 1 or 2, characterized in that the polymeric material is a polyurethane.
4. Process according to any of the foregoing claims, characterized in that the polymeric material is of between 80 and 110 Shore A hardness, preferably between 90 and 100 Shore A, in particular close to 95 Shore A.
5. Process according to any of the foregoing claims, characterized in that the or each strip (10; 10'; 110A, 110B, 110C) is of thickness (e) of between 5 and 15 mm, preferably between 8 and 10 mm.
6. Process according to any of the foregoing claims, characterized in that means of starting bending are formed in the or each strip (10; 10 ; 110A, 1110B, 110C), in particular several notches (12) or several grooves (12').
7. Process according to any of the foregoing claims, characterized in that the or each strip (10; 10'; 110A, 110B, 110C) is fastened with respect to the axle by means of at least one mechanical holding element (14; 14').
8. Railway vehicle axle (2; 2' ; 102), intended to connect at least two wheels (4; 104) of the said vehicle, provided with at least one protective flexible strip (10; 10 ; 110A, 110B, 110C), made of a polymeric material, the or each strip being wrapped round a corresponding area (2; 2'; 102A, 102B, 102C) of the axle to be protected, particularly with respect to ballast thrown upwards and for which means (14) are also provided, with which the or each strip (10; 10 ; 110A, 110B, 110C) can be fastened with respect to the axle (2; 2'; 102), characterized in that the or each strip (10; 10'; 110A, 110B, 110C) is provided, at its longitudinal ends, with two chamfered faces (10₁,10₂; 10'₁, 10'₂) which are in contact with each other.
9. Axle according to claim 8, characterized in that it is provided with at least one auxiliary element, in particular with at least one brake disc (105), defining several areas (102A, 102B, 102C) to be protected, running between the or each auxiliary element and/or the wheels, when there is provision for several protective strips (110A, 110B, 110C), each of which runs round a corresponding area.
10. Axle according to claim 8 or 9, characterized in that the polymeric material is a polyurethane.
11. Axle according to any of claims 8 to 10, characterized in that the polymeric material is of between 80 and 110 Shore A hardness, preferably between 90 and 100 Shore A, in particular close to 95 Shore A.
12. Axle according to any of claims 8 to 11, characterized in that the or each strip (10; 10'; 110A, 110B, 110C) is of thickness (e) of between 5 and 15 mm, preferably between 8 and 10 mm.
13. Axle according to any of claims 8 to 12, characterized in that the or each strip (10; 10'; 110A, 110B, 110C) is provided with means of starting bending, in particular with several notches (12) or several grooves (12').
14. Axle according to any of claims 8 to 13, characterized in that the means of fastening the or each strip (10; 10'; 110A, 110B, 110C) with respect to the axle (2; 2'; 102) comprise at least one mechanical holding element (14).
15. Railway vehicle bogie comprising several axles (2; 2'; 102), each of which connects at least two wheels (4; 104) of the said railway vehicle, characterized in that each axle is according to any of claims 8 to 14.

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