EP3378723B1 - Railway vehicle bogie comprising axles rigidly attached to the frame of the bogie - Google Patents

Description

The present invention relates to a railway vehicle bogie according to the preamble of claim 1.

The invention also relates to a railway vehicle of the type described above.

Such a bogie, in which the wheels are fitted with a tire, called a carrier tire, is particularly intended for a railway vehicle of the metro or tramway type, traveling on rolling tracks.

In such a bogie, the elasticity of the tires can be used to simplify the structure of the bogie by not providing any suspension element between the frame and the axles because the function of these elements can be fulfilled by the tires.

However, it is all the same necessary to provide elastic elements in the bogie in order to allow the latter to undergo torsion in the longitudinal direction. In fact, this characteristic is necessary to allow the bogie to pass the left-hand sides of the tracks, that is to say the zones in which the points of contact of the wheels of the bogie with the ground are not in the same plane, particularly in case of a tire puncture.

Thus, the structure of the bogie remains complex due to the need either to elastically articulate different parts of the frame of the bogie between them, or to introduce a so-called primary suspension stage between the frame and the axles. In the first case, provision is made in particular for elastically articulating the beams to one or more crosspieces connecting the beams together. Consequently, the assembly of the bogie is complicated by the assembly of the elastic articulation elements or by the assembly of the primary suspensions.

Examples of bogies for railway vehicles are described in the documents EN 2169448 , US 2036194 and FR 1310469 .

One of the aims of the invention is to overcome these drawbacks by proposing a simplified bogie structure whose assembly is facilitated.

To this end, the invention relates to a bogie according to claim 1.

By providing side members extending in the longitudinal direction interconnected by the axle casings, that is to say the chassis of which does not include an additional cross member linking the side members together, it is possible to take advantage of the flexibility of the beams to give the bogie the ability to undergo torsion about a longitudinal axis without an elastic hinge element in the bogie frame or between the beams and the axles. Thus, the axle housings can be rigidly fixed to the spars, that is to say without elastic articulation elements, which simplifies the structure of the bogie and its assembly. The invention therefore makes it possible to switch from a bogie with an articulated frame or from a bogie with primary suspension, to a flexible bogie while retaining the same capacities in terms of suspension and torsion.

According to other embodiments, the bogie according to the invention has one or more of the characteristics of claims 2 to 8, taken separately or in any technically possible combination.

The invention also relates to a railway vehicle comprising a bogie as described above.

• la figure 1 est une représentation schématique en perspective d'un bogie selon l'invention,
• la figure 2 est une représentation schématique en perspective du bogie de la figure 1, dans lequel les roues ont été retirées, et
• la figure 3 est une représentation schématique en coupe selon l'axe III-III de la figure 2.

Other aspects and advantages of the invention will appear on reading the following description, given by way of example and made with reference to the appended drawings, in which:

• the figure 1 is a schematic representation in perspective of a bogie according to the invention,
• the picture 2 is a schematic representation in perspective of the bogie of the figure 1 , in which the wheels have been removed, and
• the picture 3 is a schematic sectional representation along the III-III axis of the figure 2 .

In the description, the term “longitudinal” is defined with respect to the direction of travel of a railway vehicle, that is to say according to the direction in which the rolling tracks on which the railway vehicle travels extend. The term "transverse" is defined by a direction corresponding to the width of a railway vehicle, that is to say a direction substantially perpendicular to the longitudinal direction and extending in a horizontal plane when the railway vehicle is traveling on horizontal rolling tracks. The term "elevation" is defined by a direction substantially perpendicular to the longitudinal and transverse directions, that is to say a direction substantially vertical when the railway vehicle is traveling on horizontal rolling tracks.

With reference to the figure 1 , a railway vehicle bogie 1 is described comprising a frame 2 and two axles 4 mounted on the frame 2.

The frame 2 comprises two beams 6 each extending in a longitudinal direction and spaced from each other in the transverse direction. Each spar 6 is formed by a metal section, for example steel.

The profile has in cross section, that is to say in a plane extending in a transverse direction and in a direction of elevation, the shape of an I, as shown in the picture 3 . Thus, the cross section of the spar 6 comprises a web 8 extending in a plane extending in the longitudinal direction and in the direction of elevation and two flanges 10 extending on either side of the core 8. The flanges 10 extend in planes substantially perpendicular to the plane of the core 8, that is to say in planes extending in the longitudinal direction and in the transverse direction. Thus, the profile comprises an upper flange 10a and a lower flange 10b extending respectively above and below the web 8 in the direction of elevation. Such a shape of profile makes it possible to impart a certain flexibility or flexibility to the spar 6 in the longitudinal direction. Thus, the spar 6 is capable of undergoing a torsion around an axis A extending in the longitudinal direction along the web 8 substantially equidistant from the two flanges 10. According to one embodiment, the torsion around the axis A can go up to 1° for a bogie with approximately 2 m wheelbase. Such a torsion occurs in particular when crossing a left track of 10 mm/m while driving on the auxiliary wheels or else in the event of a puncture of a carrier tire, as will be described later. The side member used in the bogie according to the invention does not have a closed section, as is the case in the side members having a box structure, which makes it possible to confer on it this torsion capacity unlike side members having a structure box, which are particularly rigid. Thus, although the profile described above has the shape of an I, it is understood that this profile could have a different shape as long as this shape is adapted so that the spar has a certain flexibility or flexibility around its longitudinal axis A.

According to the embodiment shown in the figure 1 and 2 , each spar 6 comprises two longitudinal end portions 12 extending at each end of the spar 6 in the longitudinal direction. The longitudinal end parts 12 each extend in a transverse direction towards the outside of the bogie 1. The longitudinal end parts 12 are arranged to each carry a guide wheel 14, as shown on the figure 1 . Each guide wheel 14 extends substantially transversely and is arranged to bear against a guide surface (not shown) extending on one side of the rolling tracks on which the railway vehicle is running. Indeed, in the case of a bogie comprising wheels provided with tires, as will be described later, the railway vehicle does not run permanently on rails and guidance of the bogie is necessary, in particular in bends, and this guidance can be achieved by guide surfaces extending on either side of the rolling tracks, and by the contact of the guide wheels 14 with these guide surfaces. The guide wheels 14 are for example each provided with a tire and is rotatable around an axis Z extending in the direction of elevation relative to the longitudinal end portions 12.

Each spar 6 further comprises fixing zones 16 allowing the fixing of the axles 4 and possibly of a motor 18, as will be described later. The fixing zones 16 are for example provided with one or more orifices in the upper sole 10a allowing the screwing of a screw 19 or the bolting of a bolt in the sole as will be described later.

Each axle 4 comprises two wheels 20 connected to a connecting device arranged in an axle housing 22.

Each wheel 20 extends at a transverse end of the axle 4 so that the wheels 20 of an axle 4 extend on either side of the side members 6 of the frame 2, as shown in the figure 1 . Each wheel 20 is provided with a tire 21, called carrier tire, and is rotatable around an axis of rotation B extending in a substantially transverse direction. Each axle 4 may further comprise two auxiliary wheels 23 each arranged next to one of the wheels 20. Such auxiliary wheels 23 are arranged to allow movement on rails, for example in areas without rolling tracks for tires carriers 21.

The connecting device extends transversely from one wheel 20 to the other (or from one auxiliary wheel 23 to the other) and is for example formed by one or more shafts integral in rotation with the wheels 20, and for example driven in rotation by a reduction gear 24 disposed between the side members 6 in the case of a motor bogie, as will be described later.

The shaft or shafts and the reducer 24 are housed, at least partially and rotatable in the axle housing 22 which extends at least from one side member 6 to the other. The axle housing 22 therefore forms a sheath whose shape is adapted to receive the shaft or shafts and the reducer 24. At the level of the reducer 24, the axle housing 22 is for example open for the passage of a shaft of entry 26 of the reducer 24. The axle housing 22 is rigidly fixed to each spar 6 and provides a connection between these spars 6. By rigid fixing, it is meant that the axle housing 22 is not movable with respect to the beams 6. Thus, there is no suspension element or elastic articulation provided between the axle housing 22, and more generally the axle 4, and the beams 6. The fixing of the axle housing 22 to a spar 6 is made in a fixing zone 16 of the latter, for example by screwing at least one screw 19 or bolting a bolt passing through a plate 28 of the axle housing 22 in the orifice provided at this effect in the top flange 10a of the spar. According to an embodiment represented on the figure 1 and 2 , the fixing of the axle housing 22 of an axle 4 on a spar 6 is done by two screws 19 extending on either side of the axle housing 22 in the longitudinal direction. It should be noted that the figures show a bogie 1 in which the axles 4 are fixed to the upper flange 10a of the side members 6, the axles therefore extending above the side members 6. However, according to another embodiment, the axles 4 could be fixed on the bottom flange 10b of the side members 6 and extend below them.

The axle casings 22 are rigidly fixed to the beams 6, each in the vicinity of a longitudinal end part 12 of the beams 6, so that the axles 4 and the beams 6 form a rigid frame according to the direction of elevation and according to the transverse direction. This assembly is however capable of undergoing a torsion around a longitudinal axis A′ extending substantially equidistant from the longerons 6 between them due to the flexibility of the longerons 6 in this longitudinal direction, as described previously. The bogie 1 according to the invention is therefore able to take up the forces in the direction of elevation thanks to the elasticity of the tires 21 and to pass the twists and turns thanks to this ability to undergo a torsion around a longitudinal axis then even as the bogie 1 has no suspension element and elastic articulation element.

According to the embodiment shown in the figure 1 and 2 , the bogie 1 is a motor bogie comprising a motor 18 arranged to drive the wheels 20 in rotation via the reducers 24.

In a conventional manner, the motor 18 is connected to the reduction gears via the input shafts 26. The motor 18 is placed, at least partially, in a motor casing 30 extending substantially transversely from a spar 6 to the each other and placed, in the longitudinal direction, between the axles 4. The engine casing 30 is fixed rigidly to each of the longitudinal members 6. As for the axles 4, by rigid attachment is meant that the engine casing 30 is not movable relative to the side members 6 and there is no suspension element or elastic joint provided between the engine casing 30 and the side members 6. According to one embodiment, the engine casing motor 30 is fixed by screwing or bolting in a fixing zone 31 of the longerons 6. Thus, the motor casing 30 also participates in the connection of the longerons 6 between them.

It will be noted that the bogie frame 2 described above comprises only two side members 6 and no mechanically welded connection between these two side members, such as a cross member or the like, this function being fulfilled by the axle casings 22, and possibly the engine casing 30. Such a chassis structure makes it possible to give it the desired flexibility around the longitudinal axis A′, in particular when crossing left-hand tracks when the bogie is running on the auxiliary wheels 23 or in puncture of a carrier tire 21. The mounting of the chassis is thus particularly simple since it can be obtained by simple screwing or bolting operations. By way of example, eight screwing or bolting operations are sufficient to obtain the bogie when each axle casing 22 is fixed to each beam 6 by two screws or two bolts.

The bogie has been described as comprising a motor 18, that is to say a motorized bogie, driving the wheels 20 of the two axles 4 in rotation. It is however understood that the invention could apply to a motorless bogie, whose wheels are driven in rotation due to the drive by another motorized bogie, or to a bogie whose motor does not rotate the wheels only one axle 4 on both.

The invention also relates to a railway vehicle comprising one or more bogies as described above. Such a railway vehicle is, for example, a metro or a tramway arranged to travel on rolling tracks which, at least in part, have no rails and which comprise guide surfaces on the sides, in at least certain zones.

Claims (9)

1. - A railway vehicle bogie (1), comprising a chassis (2) and two axles (4), the chassis (2) comprising two longitudinal members (6) extending in a longitudinal direction, each axle (4) comprising a pair of wheels (20) each provided with a tyre (21) and a connecting device extending between said wheels (20), characterized in that each axle (4) comprising an axle housing (22) extending in a transverse direction substantially perpendicular to the longitudinal direction and at least partially surrounding the connecting device, the longitudinal members (6) of the chassis (2) being connected to each other by the axles (4), the axle housing (22) of each axle (4) being rigidly attached to each of said longitudinal members (6),
   characterised in that each longitudinal member (6) has a cross-section comprising a web (8) extending in an elevation direction substantially perpendicular to the longitudinal and transverse directions and two flanges (10, 10a, 10b) extending in a substantially transverse direction on either side of the web (8) in the elevation direction.
2. The railway vehicle bogie according to claim 1, wherein each longitudinal member (6) has a flexibility such that the bogie (1) has a degree of freedom in bending about a longitudinal axis (A') substantially parallel to the longitudinal members (6) and extending between said longitudinal members (6).
3. The railway vehicle bogie according to claim 1 or 2, wherein the axle housing (22) of each axle (4) is attached to each longitudinal member (6) by at least one screw (19) or bolt.
4. The railway vehicle bogie according to any of claims 1 to 3, wherein the connection between the chassis (2) and the axles (4) is free of any hinge or elastic suspension element.
5. The railway vehicle bogie according to any one of claims 1 to 4, wherein each longitudinal member (6) comprises at each of its longitudinal end portions (12) a guide wheel support (14), said longitudinal end portions (12) extending in a direction substantially transverse to the rest of the longitudinal member (6).
6. The railway vehicle bogie according to any of claims 1 to 5, further comprising a motor (18) extending between the longitudinal members (6) and between the axles (4) and a motor housing (30) extending at least partially around the motor (18).
7. The railway vehicle bogie according to claim 6, wherein the longitudinal members (6) of the chassis (2) are connected to each other by the motor housing (30), said motor housing (30) being rigidly attached to each of said longitudinal members (6).
8. The railway vehicle bogie according to claim 6 or 7, wherein the connecting device between the wheels (20) of each axle (4) comprises a gearbox (24) connecting the motor (18) to each of the wheels (20), said gearbox being housed in the axle housing (22) between the longitudinal members (6).
9. A railway vehicle comprising at least one bogie according to any of claims 1 to 8.

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