EP1826092B1 - Wheelset for a lowfloor rail vehicle, bogie and rail vehicle comprising such a wheelset - Google Patents

Description

The present invention relates to a railway vehicle axle of the type comprising a central shaft, two wheels connected in rotation by the shaft and two bearings, each wheel being rotatably mounted relative to a bearing along the axis of the wheels, a bogie comprising a such axle, and a railway vehicle comprising such a bogie.

Such axles are conventionally used for rail vehicles, particularly for urban rail transport, of the tramway type. These conventional axles equip bogies supporting vehicle bodies whose floor is, generally, above the axles, at a height of 520 mm above the upper edge of the rails with standard wheels 590 mm in diameter at the new condition. In urban areas, and therefore without a platform, this floor height represents a difficulty for passenger access, for example, in a tramway.

The document WO 0 / 64,721 describes a railway vehicle with, on the one hand, a lowered floor above the axles of a height, above the upper edge of the rails, of 450 mm thanks to wheels of diameter smaller than the standard diameter and, on the other hand, a floor area of lesser height, approximately 355 mm above the rails, connected by ramps to the floor area above the axles, this lower area being an area of easy access for passengers.

There are also axles bent. Such axles, described for example in the document EP 911 239 , are located under the axis of rotation of the wheels, by making it possible to lower the floor at the level of the axles of the wheels, thanks to a complex arrangement of transmission of the driving torques to the wheels. These axles comprise in fact angular references and / or reducers allowing the implementation of a remote rotary connection shaft parallel to the axis of rotation of the wheels.

The disadvantages of these two types of axles are, in the first case, the need to use non-standard wheels and, in the second case, a complexity and therefore a high cost of manufacturing the axles.

The object of the invention is therefore to provide a lowered floor vehicle without the disadvantages mentioned above.

To this end, the subject of the invention is an axle for a railway vehicle of the aforementioned type, characterized in that it furthermore comprises at least one bending stiffening cross member of the axle, this cross member rigidly connecting the two bearings, and that the diameter of the shaft is between 60 and 140 mm.

Other features of the invention appear in claims 2 to 6.

The invention also relates to a bogie comprising a chassis and at least one axle as defined above supporting said bogie.

The invention also relates to a rail vehicle comprising a body and at least one bogie as defined above for the support of the body.

• les roues ont un diamètre compris entre 530 et 660 mm, et le véhicule comprend un premier plancher d'une hauteur comprise entre 385 et 510 mm au-dessus du bord supérieur des rails dans la région du bogie ; et
• le véhicule ferroviaire comprend un second plancher d'une hauteur comprise entre 335 et 375 mm les deux planchers étant reliés par une rampe d'inclinaison comprise entre 5 et 10%.

According to other features of the invention, in the case for example of a tramway:

• the wheels have a diameter of between 530 and 660 mm, and the vehicle comprises a first floor with a height between 385 and 510 mm above the upper edge of the rails in the region of the bogie; and
• the railway vehicle comprises a second floor with a height of between 335 and 375 mm, the two floors being connected by a ramp of inclination of between 5 and 10%.

• la figure 1 est une vue schématique de dessus d'un bogie équipé de deux essieux selon l'invention ;
• la figure 2 est une vue schématique de face sensiblement suivant la flèche II de la figure 1, montrant un essieu ;
• la figure 3 est une vue de profil d'un véhicule ferroviaire avec deux niveaux différents de plancher ; et
• la figure 4 est une vue analogue à celle de la figure 2, montrant un essieu selon une variante de l'invention.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings, in which:

• the figure 1 is a schematic top view of a bogie equipped with two axles according to the invention;
• the figure 2 is a schematic front view substantially along the arrow II of the figure 1 , showing an axle;
• the figure 3 is a side view of a rail vehicle with two different floor levels; and
• the figure 4 is a view similar to that of the figure 2 , showing an axle according to a variant of the invention.

The bogie 1 of the figure 1 essentially comprises a chassis 5, two pairs of wheels 9 each integrated in an axle 11, and a suspension system 15 interposed between the axles 11 and the chassis 5.

The chassis 5 has the general shape of H with two spars 17, parallel to the longitudinal axis X of the truck 1. Each spar 17 has two zones 18 of difference in elevation, the median part of the spar between the two axles 11 being lower than the ends of the spar. The two longitudinal members 17 are connected by a transverse central beam 19 perpendicular to the longitudinal members 17. The chassis 5 is intended to support a body 20 of a vehicle, such as a tramway. The body 20 is, for example, articulated in the center of the beam 19.

Each axle 11 comprises a central shaft 21 which extends transversely along the entire width of the axle. It connects the two wheels 9 in rotation and extends along the Y axis of common rotation of the two wheels.

Two bearings 22, each located against a wheel 9, support the frame 5. Each wheel 9 is rotatably mounted relative to a bearing 22.

A crossbar 23, visible on the figure 2 , for example cylindrical and of rectangular section, rigidly connects the two bearings 22 to each other by their lower ends, to the right of the shaft 21. The crossbar 23 is thus parallel to the axis Y of rotation of the wheels 9 and located under the shaft 21. it is slightly spaced from the latter by a distance l advantageously for a tram between 80 and 120 mm, for example of the order of 100 mm.

The two bearings 22 each have a bearing surface of the suspension system 15.

The wheels 9 have a diameter D advantageously between 530 mm and 620 mm, for example of the order of 590 mm. 590 mm is the diameter standard for tramway wheels, in new condition. The standard 9-wheel diameter can go down to 530 mm with wear. The wheels 9 are placed on rails 24.

The diameter d of each shaft 21 is advantageously between 60 mm and 140 mm, for example of the order of 100 mm.

The crosspiece 23 has a section at least equal to that of the shaft 21.

Bogie control members, such as a speed reducer 26 or a motor, for example, are housed in one or more bearings 22.

The floor 31 of the body 20 of the vehicle, located just above the axle 11, is spaced from the axle 11 of an interval i. The interval i, corresponding to the deflection of the suspensions 15, is advantageously between 40 and 80 mm, of the order of 60 mm for example. The floor 31 is of a thickness e, advantageously between 30 and 70 mm, for example of the order of 50 mm.

h est donc compris entre ${\underline{\mathrm{h}}}_{\min }\mathrm{=}\frac{\mathrm{Dmin}}{\mathrm{2}}\mathrm{+}\frac{\mathrm{dmin}}{\mathrm{2}}\mathrm{+}{\mathrm{e}}_{\min }\mathrm{+}{\mathrm{i}}_{\min }\mathrm{=}\mathrm{365}\mathrm{mm}$

et ${\underline{\mathrm{h}}}_{\max }\mathrm{=}\frac{\mathrm{Dmax}}{\mathrm{2}}\mathrm{+}\frac{\mathrm{dmax}}{\mathrm{2}}\mathrm{+}{\mathrm{e}}_{\max }\mathrm{+}{\mathrm{i}}_{\max }\mathrm{=}\mathrm{530}\mathrm{mm},$

de l'ordre de 455 mm par exemple.The inside of the floor 31 is thus at a height h of the top of the rail which is a function of D, d, e and i according to the relation: $$\mathrm{h}\mathrm{=}\frac{\mathrm{D}}{\mathrm{2}}\mathrm{+}\frac{\mathrm{d}}{\mathrm{2}}\mathrm{+}\mathrm{e}\mathrm{+}\mathrm{i}$$

h is therefore between ${\underset{}{\mathrm{h}}}_{\min }\mathrm{=}\frac{\mathrm{dmin}}{\mathrm{2}}\mathrm{+}\frac{\mathrm{dmin}}{\mathrm{2}}\mathrm{+}{\mathrm{e}}_{\min }\mathrm{+}{\mathrm{i}}_{\min }\mathrm{=}\mathrm{365}\mathrm{mm}$

and ${\underset{}{\mathrm{h}}}_{\max }\mathrm{=}\frac{\mathrm{Dmax}}{\mathrm{2}}\mathrm{+}\frac{\mathrm{dmax}}{\mathrm{2}}\mathrm{+}{\mathrm{e}}_{\max }\mathrm{+}{\mathrm{i}}_{\max }\mathrm{=}\mathrm{530}\mathrm{mm},$

of the order of 455 mm for example.

The beam 19 connects the longitudinal members 17 passing under the floor 31.

The operating principle of the invention is to optimize the vertical space requirement of the axle 11 by reducing it to the maximum in height, in order to free up space to descend as far as possible to the floor 31 of the body 20 of the vehicle.

The traditional functions of the axle 11 are separated here. Indeed, an axle 11 must generally, firstly secure the wheels 9 and rotate them by transmitting the traction and braking torques, the wheels 9 thus rotating together and parallel, and, secondly, withstand the bending forces due to the mass of the vehicle and the chassis 5, transmitted by the suspension system 15.

The truck 1 separates the functions of the axle 11 between, on the one hand, the central shaft 21 which fills the first function of the axle, and secondly, the cross member 23 which performs the second function.

The crossbar 23 has in fact sufficient inertia to resist bending due to the forces from the vehicle and the chassis. The crossbar 23 does not rotate, and only the shaft 21 drives the wheels 9 in rotation.

Thus, the only dimensioning constraint of the central shaft 21 is the driving function of the wheels 9 by the shaft 21, which can therefore be of smaller diameter than if it fulfilled the two functions of the axle 11.

As the height h of the floor 31 of the body 20 above the upper edge of the rails 24 is limited by the radius R / 2 of the wheels 9 plus the radius d / 2 of the shaft 21, and a minimum interval i , the invention allows a lowering of the floor 31 to the height h of 455 mm, taking into account also the thickness of the floor 31.

In addition, an axle 11 allows a simple transmission system, the first function of the axle being retained, thanks to the central shaft 21.

As shown in figure 3 in the vehicle 33, a ramp inclination of less than 10% is advantageously provided for connecting the floor 31 of the area above the bogie to a lower floor zone 39 h ' . This zone 39 of lower height h ' is for example the passenger access zone. This results in a relatively low floor level 39 for the passenger access area, of the order of 355 mm.

Alternatively, each axle comprises two cross members, for example in the case (not shown) where the bearings are located outside the wheels. Each crossbar connects the two bearings, the first crossbar being located in front of the wheels and the second behind the wheels, symmetrically with respect to the shaft.

In the embodiment of Figures 1 and 2 the cross member 23 of each axle 11 is located under the corresponding shaft 21, and spaced therefrom. The shaft 21 is located outside the crossbar 23.

The embodiment illustrated on the figure 4 , where numerical references to elements similar to those of the figure 2 have been preserved, differs from that of the figure 2 in that the cross-member 23 surrounds the shaft 21. In other words, the shaft 21 extends inside the cross-member 23.

The crossbar 23 is nevertheless located at a height lower than that of the conventional axle for the same application with respect to the tops of the rails 24. More specifically, the crossbar 23 is made with a neutral surface of the crossbar located below the axis of the tree.

The neutral bending surface under vertical load of the beam is called the location of the points of zero longitudinal stress in flexion under a vertical load due to the chassis 5 and to a rail vehicle resting on the chassis

To do this, the crossbar 23 has for example more material in the lower part, between the shaft 21 and the top of the rail, in the upper part, above the shaft 21. In the example shown, the crossbar 23 is offset vertically relative to the shaft 21 so that the clearance Jsup between the shaft 21 and the upper inner wall of the crossmember 23 is less than the clearance Jinf between the shaft 21 and the lower inner wall of the crossbar 23.

The crosspiece 23 defines with the bearings 22 a sealed volume around the shaft 21, between the bearings 22.

Thus, the outlets of the bearings 22 on the inside (on the side of each bearing 22 opposite the adjacent wheel 9) are sealed by the crosspiece 23, and it is not necessary to provide additional sealing means. Only the outlets of the bearings 22 outer side must be provided with sealing means. This has the advantage of simplifying the bearings 22 and reducing the manufacturing cost of the axle 11.

In this embodiment, the distance i between the shaft 21 and the floor 31 must be sufficient to accommodate the upper wall of the cross member 23 (which is for example of the order of 10 mm), and arrange a sufficient Jsup clearance (for example of the order of 10 mm). As a result, the height of the floor 31 is greater than that which can be obtained with the embodiment of the figure 2 (for example greater than 20 mm).

Claims (10)

1. An axle (11) for a rail vehicle (33) of the type comprising a central shaft (21), two wheels (9) connected in terms of rotation by the shaft (21) and two bearings (22), each wheel (9) being mounted so as to rotate relative to a bearing (22) along the axis (Y) of the wheels (9), the central shaft (21) extending along the axis (Y) of the wheels, characterised in that it further comprises at least one cross-piece (23) for reinforcement of the axle (11) in terms of flexion, this cross-piece (23) rigidly connecting the two bearings (22), and in that the diameter (d) of the shaft (21) is between 60 and 140 mm.
2. The axle (11) according to Claim 1, characterised in that the or each cross-piece (23) is located at a height lower than the height of the shaft (21), relative to the tops of the rails (24).
3. The axle (11) according to Claim 1, characterised in that the shaft (21) extends inside the cross-piece (23).
4. The axle (11) according to Claim 3, characterised in that the cross-piece (23) is offset vertically relative to the central shaft (21) such that the play (Jsup) between the shaft (21) and the upper inner wall of the cross-piece (23) is less than the play (Jinf) between the shaft (21) and the lower inner wall of the cross-piece (23).
5. The axle (11) according to any of the preceding claims, characterised in that the cross-piece (23) has a cross-section at least equal to that of the shaft (21).
6. The axle (11) according to Claim 3, characterised in that the cross-piece (23) defines, with the bearings (22), a sealed space around the shaft (21).
7. A bogie (1) for a rail vehicle (33) characterised in that it comprises bodywork (5) and at least one axle (11) according to any of the preceding claims supporting said bogie.
8. A rail vehicle (33), characterised in that it comprises a body (20) and at least one bogie (1) according to Claim 7 for supporting the body.
9. The rail vehicle (33) according to Claim 8, characterised in that the wheels (9) have a diameter (D) of between 530 and 660 mm, and the vehicle (33) comprises a first floor (31) having a height (h) of between 385 and 510 mm above the upper edge of the rails (24) in the region of the bogie.
10. The rail vehicle (33) according to Claim 9, characterised in that it comprises a second floor (39) having a height (h') of between 335 and 375 mm, the two floors (31, 39) being connected by a ramp (35) with an inclination of between 5 and 10%.

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