Railway vehicle bogie including steerable wheels

Abstract

A railway vehicle bogie (1), the bogie (1) comprising at least one main structure (2) connecting a first wheel (R1) and a second wheel (R2), each wheel (R1, R2) extending radially in an elementary plane (Xi, Z), each wheel (R1, R2) being configured to rotate about an elementary transverse axis (Yi) orthogonal to the elementary plane (Xi, Z), the U-shaped main structure (2) comprising two arms (3) and a transverse member (4) connecting the two arms (3), the main structure (2) being configured to be connected, in a hinged manner about the vertical axis (Z), to a railway vehicle chassis, the bogie (1) comprising at least one first elementary steering device (5) for the first wheel (R1) configured to modify the inclination of the elementary transverse axis (Yi) of the first wheel (R1) so as to tilt the elementary plane (Xi, Z) of the first wheel (R1) according to the vertical axis (Z). Abbreviated figure: Figure 6

Description

Title of the invention: Railway vehicle bogie comprising steerable wheels Technical field

[0001] The present invention relates to the field of railway vehicles and more specifically to the field of bogies for railway vehicles. The invention relates in particular to a railway vehicle bogie comprising steerable wheels.

[0002] In a known manner, with reference to [Fig.l], a railway vehicle W comprises a plurality of railway cars V, each mounted on at least two bogies 101 in contact with the running rails Ql, Q2 of a railway track. A bogie 101 is a carriage, rotatable relative to the railway car V, which generally comprises one or more axles 102, each axle 102 being mounted between two wheels RI, R2. Each wheel RI, R2 is respectively in contact with one of the running rails Ql, Q2 of the railway track, via a running table TRI, TR2, as shown in [Fig.2].

[0003] More precisely, as is known and shown in [Fig.2], a running rail Ql comprises a lower part Q12, which rests on the ground, and an upper part, designated “head” Ql 1, adapted to be in contact with the wheels RI, R2 of the railway vehicle W. The running table TRI, TR2 of each wheel RI, R2 is in contact with an upper face of the head Ql 1.

[0004] In a known manner, a wheel RI, R2 of a railway vehicle W also comprises a flange B1, B2, also shown in [Fig.2], which bears on the inner lateral face of the head Ql 1 of the running rail Ql, Q2 and thus ensures the guidance of the wheel RI, R2.

[0005] With reference to [Fig. 3], when the railway vehicle W travels on a curved portion of railway track, the bogie 101 presses the flange B1, B2 of each outer wheel R1, R2 (depending on the direction of the curve) against the running rail Q1, Q2, which causes friction and therefore wear of the wheel R1, R2. The friction of the flange B1, B2 also generates a significant noise which can be a nuisance for the passengers of the railway vehicle. In addition, two wheels R1-A, R2-A connected by the same axle 102, rotate at the same rotational speed. However, on a curved section of track, the outer wheel R2-A travels a greater distance than the inner wheel Rl-A, which can cause the inner wheel Rl-A to slip against the running rail QL. The slippage causes the wheel RI, R2 to rub against the upper face of the rail head Ql 1, which can damage both the wheel RI, R2 and the running rail Ql, Q2.

[0006] To limit this drawback, there is known in the prior art from patent application WO2009071768A1 a railway vehicle bogie 101, which comprises means making it possible to modify the orientation of a first axle 102 relative to a second axle 102 when the railway vehicle is traveling on a curved portion of railway track.

[0007] More precisely, as shown in [Fig.4], the bogie 101 comprises two chassis 103, 104, each chassis 103, 104 being connected to an axle 102A (respectively 102B) mounted between two coaxial wheels R1-A, R2-A (respectively R1-B, R2-B). The chassis 103, 104 are connected by a common vertical axis Z and are articulated relative to each other along this common vertical axis Z, which forms a pivot connection. Thus the axles 102A, 102B can have different trajectories and not remain parallel.

[0008] Also known is a bogie 101 comprising two electric motors M1, M2 (also shown in [Fig.4]), each connected respectively to one of the two wheels R1-A, R2-A of the same axle 102A. Each electric motor M1, M2 controls each wheel R1, R2 independently, so as to make them rotate at different speeds, which is advantageous for example in a curved portion of railway track in which the outer wheel R2-A travels a greater distance.

[0009] However, when the railway vehicle travels on a curved portion of railway track, the articulation of the two chassis 102, 103 of the same bogie 101 is driven by the contact of the flange B2 of the outer wheels R2-A, R2-B against the running rail Q2. Also, even if the pressure of the flange B1, B2 against the running rail Q1, Q2 is lowered due to the articulation between the two axles 102, 103, the radius of curvature of the railway track causes continuous friction of the front of the wheel R1, R2, which is not desirable because it can wear or damage the wheel R1, R2 and / or the running rail Q1, Q2, as described above. This is particularly the case when the railway vehicle W travels at high speeds, during which the contact force of the flange against the running rail is high. The axle must then be removed with its wheels to correct the deformations of the two wheels.

[0010] The invention thus aims to eliminate at least some of these drawbacks by proposing a reliable railway vehicle bogie which makes it possible to limit friction between the wheel flange and the head of the running rail. The bogie according to the invention thus aims to limit premature wear of the wheels, which makes it possible to limit maintenance interventions, thereby limiting maintenance costs and times. PRESENTATION OF THE INVENTION

[0011] The invention relates to a railway vehicle bogie, the bogie comprising at least one main structure connecting a first wheel and a second wheel mounted coaxially with respect to each other, each wheel extending radially in an elementary plane in which the Z axis defines a vertical axis, each wheel being configured to rotate along an elementary transverse axis orthogonal to the elementary plane, the U-shaped main structure comprising two arms and a transverse member connecting the two arms, each arm being mechanically connected respectively to a wheel, the main structure being configured to be connected, in an articulated manner along the vertical axis, to a chassis of the railway vehicle so as to modify the orientation of the bogie relative to the chassis of the railway vehicle.The bogie is remarkable in that it comprises at least a first elementary device for orienting the first wheel, the elementary orientation device being configured to modify the inclination of the elementary transverse axis of the first wheel so as to incline the elementary plane of the first wheel along the vertical axis.

[0012] The bogie according to the invention advantageously makes it possible to modify the orientation of the first wheel independently of the orientation of the second wheel connected by the same main structure. The elementary orientation device makes it possible to adapt the orientation of the wheel to the curvature of the railway. In other words, thanks to the elementary orientation device, the direction of the elementary transverse axis of the wheel can be modified to allow the wheel to rotate along its own axis of rotation different from the axis of rotation of the second wheel mounted on the same main structure. This makes it possible to limit the friction of the wheel and in particular of the wheel flange against the running rail. The wear of the wheel is thus limited, which makes it possible to extend its service life and to limit maintenance times and costs.

[0013] When a wheel is damaged and it is necessary to correct a defect, for example to flatten the tread, the bogie according to the invention makes it possible to intervene only on the wheel which has a defect and to avoid the need to intervene on all the wheels so that they all have an equivalent diameter, as was the case in the prior art, which was time-consuming and impractical. Indeed, in the bogies of the prior art, all the wheels had to have an equivalent diameter to avoid any risk of slippage. Thanks to the invention, the elementary steering device allows each wheel to be independent of the other wheels of the bogie.

[0014] Preferably, the bogie comprises a second elementary device for orienting the second wheel, the elementary orientation device being configured to modify the inclination of the elementary transverse axis of the second wheel so as to incline the elementary plane of the second wheel along the vertical axis, so as to modify the orientation of each wheel independently. The wheels initially mounted coaxially and connected by the same main structure can thus each rotate along an independent axis different from the axis of the other wheel, which advantageously allows each to follow a different trajectory and to adapt to the running rail with which it is in contact. The friction between each wheel and the running rail is thus greatly limited, which makes it possible both to extend the service life of the wheels and to limit noise pollution for passengers on the railway vehicle.

[0015] In a first embodiment, the elementary orientation device comprises a controlled cylinder mounted between the arm and the wheel connected to said arm. A controlled cylinder advantageously makes it possible to modify the orientation of the wheel by pushing locally on the wheel with a controlled force. A controlled cylinder also makes it possible to guarantee an optimal inclination of the wheel relative to the curvature of the running rail. In other words, this makes it possible to control the inclination of the elementary transverse axis of the wheel and to modify this inclination before the wheel flange is in contact with the head of the running rail. A controlled cylinder thus makes it possible to limit even more significantly the friction between the wheel flange and the running rail.

[0016] Preferably, the piloted cylinder is chosen from an electric cylinder, a pneumatic cylinder or a hydraulic cylinder.

[0017] In a second embodiment, the elementary orientation device comprises a spring member mounted between the arm and the wheel connected to said arm, which makes it possible to modify the orientation of the wheel by means of a simple and effective device. The use of a spring also makes it possible to guarantee the return of the wheel to the axis of the railway vehicle, for example when the railway vehicle is traveling in a straight line and no more force is applied to the wheel.

[0018] Preferably, the spring is a passive spring, which ensures the assembly of a simple and efficient bogie. A passive spring also has a limited footprint.

[0019] Preferably, the elementary orientation device is configured to modify the angular position of the first wheel along the vertical axis in the plane up to a maximum angle of between - 10° and 10°. Such an angle makes it possible to adapt the orientation of the wheel effectively to any radius of curvature of a railway track while ensuring that there is no risk of the wheel flange rubbing against the inner lateral face of the head of the running rail.

[0020] In a preferred embodiment, the bogie comprises a first electric motor connected to the first wheel and controlled so as to modify the speed of the first wheel. The rotational speed of the wheel can thus be adapted independently hanging, which advantageously allows it to be adapted, for example, to a curved section of railway track, in which the outer wheel travels a greater distance. The latter can thus advantageously rotate at a higher speed than the speed of the inner wheel (relative to the curvature), which eliminates the risk of wheel slippage and thus limits the risk of damage to the wheel and the running rail.

[0021] Preferably, the bogie comprises a second electric motor connected to the second wheel and controlled so as to modify the speed of the second wheel. The two wheels can thus advantageously be driven at independent rotational speeds which can each be adapted according to the radius of curvature of a railway track. The inner wheel and the outer wheel can be accelerated or slowed down to ensure that there is no risk of slippage and therefore no risk of damage to the wheel and / or the rail due to traffic.

[0022] Preferably, the bogie comprises a plurality of vertical and transverse suspension members configured to dampen vibrations and / or correct a rolling effect of the railway vehicle. The suspension members thus make it possible to limit vibrations for the passengers of the railway vehicle.

[0023] In one embodiment, the suspension members are also configured to adapt the height of the chassis of the railway vehicle to the height of the platform. Access to the railway vehicle is thus simpler.

[0024] In a preferred embodiment, the bogie comprises two main structures, each main structure connecting a first wheel and a second wheel, each main structure being mechanically connected to a common connecting member connected to the chassis of the railway vehicle. The bogie comprising four wheels can thus advantageously adapt the orientation of each of the main structures to the curvature of the railway track, independently, which makes it possible to limit the friction of all the wheels.

[0025] The invention also relates to a railway vehicle comprising a chassis and at least one bogie as described above, the main structure of the bogie being connected to the chassis of the railway vehicle and articulated with said chassis along the vertical axis.

[0026] Preferably, the orientation along the vertical axis of the main structure relative to the chassis of the railway vehicle is carried out at a first angle of between - 10° and 10°, making it possible to ensure that the orientation of each main structure is adapted to any radius of curvature of the railway track.

[0027] Finally, the invention relates to a method for modifying the orientation of a first wheel of a railway vehicle bogie as described previously, the bogie being mechanically connected to a chassis of the railway vehicle, the method comprises the steps consisting of: • modify the orientation of the bogie relative to the chassis of the railway vehicle by a first angle, and • independently modify the orientation of the first wheel by a first orientation angle relative to the bogie arm.

[0028] The orientation of the main structure of the bogie relative to the chassis of the railway vehicle makes it possible to absorb a significant part of the curvature of a railway track and the orientation of the first makes it possible, in the end, to ensure that the wheel flange does not rub the head of the running rail.

[0029] In a preferred embodiment, the method comprises, after or simultaneously with the step of modifying the orientation of the first wheel, a step of independently modifying the orientation of the second wheel by a second orientation angle relative to the arms of the bogie. The orientation of the two wheels can thus advantageously be modified independently. PRESENTATION OF FIGURES

[0030] The invention will be better understood on reading the description which follows, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0031] [Fig.l] is a schematic representation of a railway vehicle comprising a plurality of bogies according to the prior art.

[0032] [Fig.2] is a schematic representation of flanges of the two wheels of the same axle.

[0033] [Fig. 3] is a schematic representation of a railway vehicle traveling on a curved portion of railway track.

[0034] [Fig. 4] is a schematic representation of a prior art bogie in which two axles are steerable relative to each other.

[0035] [Fig.5] is a schematic representation of a railway vehicle comprising a plurality of bogies according to one embodiment of the invention.

[0036] [Fig.6] is a schematic representation of a bogie according to a first embodiment of the invention.

[0037] [Fig.7] is a schematic representation of a connection between two bogies of [Fig.6] and the railway vehicle of [Fig.5].

[0038] [Fig.8] is a schematic representation of an elementary device for orienting a wheel of the bogie of [Fig.6] according to a first embodiment.

[0039] [Fig.9] is a schematic representation of an elementary device for orienting a wheel of the bogie of [Fig.6] according to a second form of rea- lization.

[0040] [Fig. 10] is a schematic representation of an elementary device for orienting a wheel of the bogie of [Fig. 6] according to a third embodiment.

[0041] [Fig. 11] is an example of the basic orientation of each wheel of a bogie of [Fig.6] on a curved portion of railway track.

[0042] [Fig. 12] is a representation of the elementary axes of each elementary reference frame of the two wheels of the bogie of [Fig.6] when the bogie is in the curved portion of the railway track of [Fig.9].

[0043] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0044] With reference to [Fig. 5], in a known manner, a railway vehicle W comprises a plurality of railway cars V, each mounted on at least two bogies 1 in contact with the running rails Q1, Q2 of a railway track. A bogie 1 is a trolley, movable in rotation relative to the railway car V. For the sake of simplicity, the railway vehicle W shown in [Fig. 5] comprises two railway cars V, however it goes without saying that the railway vehicle W can comprise a different number of railway cars V.

[0045] Subsequently, in this document, the railway vehicle W is described in an orthogonal reference frame (X, Y, Z), in which the X axis extends longitudinally from the rear to the front of the railway vehicle W in its direction of travel, the Y axis extends transversely from the right to the left for a person positioned in the railway vehicle W and facing the front of the railway vehicle W, and the Z axis extends vertically from the bottom to the top, as shown in [Fig. 5]. Subsequently, the terms "inner" and "outer" are understood in relation to the two running rails Q1, Q2 which define an inner gap between them. The same will apply to two wheels mounted opposite each other as will be described in more detail later.

[0046] In this example, the railway vehicle W comprises a plurality of bogies 1 according to the invention. All the bogies 1 being identical, for the sake of clarity, only one bogie 1 will be described subsequently.

[0047] Preferably, the bogie 1 is connected to a chassis CH of the railway car V. More preferably, the bogie 1 is articulated with the chassis CH along the vertical axis Z to allow the railway vehicle W to travel on a portion of curved railway track.

[0048] In one embodiment, shown in [Fig.7], the bogie 1 is connected to a intermediate connecting member L, itself connected to the chassis CH of the railway car V. In this example, the bogie 1 is connected to the connecting member L by means of two connecting rods 6 which make it possible to articulate the connecting member L in each of the directions of the orthogonal reference frame (X, Y, Z), thus making it possible to absorb at least part of the movements of the bogie 1 on the railway track and to limit the vibrations felt by the passengers. It goes without saying that the connection between the bogie 1 and the connecting member L could be different, for example fixed by means of bolted connections or articulated by means of suitable mechanical members such as jacks for example. In this embodiment, the connecting member L is articulated with the chassis CH of the railway car V along the Z axis, by means of a pivot connection P (shown in [Fig.7]).The connecting member L could alternatively be connected to the chassis CH by a fixed connection or a ball joint for example. In this embodiment, the connecting member L is preferably pre-assembled to the bogie 1, which allows the assembly to be connected to the railway vehicle W in a single operation, allowing simple and rapid installation. In the event of maintenance, when necessary, the replacement of the entire bogie 1 also allows a significant saving of time. It goes without saying that the bogie 1 could alternatively be connected directly to the chassis CH of the railway vehicle W, by means of connecting rods or jacks for example, as shown in [Fig. 10].

[0049] In a preferred embodiment, still with reference to [Fig. 10], the bogie 1 is articulated so as to allow rotation along the Z axis of the bogie 1 relative to the chassis CH of the railway car V at a first angle a, preferably between - 10° and 10°. In other words, the articulation allows the bogie 1 to be offset relative to the longitudinal axis X of the railway vehicle W, allowing the railway vehicle W to travel along a curved portion of railway track.

[0050] According to one aspect of the invention, with reference to [Fig. 6], the bogie 1 comprises a main structure 2 connecting a first wheel RI and a second wheel R2 mounted coaxially with respect to each other. This document describes a bogie 1 comprising a single main structure 2 connecting two wheels RI, R2. In an alternative embodiment, shown in [Fig. 7], the bogie 1 comprises two main structures 2A, 2B, each connecting two wheels R1-A, R2-A (respectively RI-B, R2-B). The two main structures 2A, 2B are preferably identical. For the sake of clarity and conciseness, the bogie 1 will be described below for a single main structure 2 connecting two wheels RI, R2.

[0051] Each wheel RI, R2 is respectively in contact with one of the running rails Q1, Q2 of the railway track, via a running table TRI, TR2 (as shown in [Fig.5]). In a known manner, a wheel RI R2 of a railway vehicle W also comprises a flange B1, B2, which bears on the inner lateral face of a mushroom Q11, Q21 of the running rail Ql, Q2 and thus ensures the guidance of the wheel RI, R2 on the railway track.

[0052] As shown in [Fig.6], each wheel RI, R2 extends in an elementary plane (Xi, Z) in which the axis Z corresponds to the vertical axis Z of the railway vehicle W. More precisely, each wheel RI, R2 comprises a web RI 1 which has the shape of a solid disc and extends on an inner face of the wheel RI, R2. The web RI 1 extends in the elementary plane (Xi, Z). Each wheel RI, R2 is configured to rotate along an elementary transverse axis Yi orthogonal to the elementary plane (Xi, Z). When the railway vehicle W travels on a straight line, the elementary longitudinal axis Xi and the elementary transverse axis Yi of the wheel RI, R2 correspond respectively to the longitudinal axis X and the transverse axis Y of the railway vehicle W.

[0053] Still with reference to [Fig.6], the main structure 2 has a U-shape and comprises two arms 3 and a transverse member 4 connecting the two arms 3. Each arm 3 is mechanically connected respectively to a wheel RI, R2. Each arm 3 is connected to the associated wheel RI, R2 by a pivot axis to allow said wheel RI, R2 to rotate. In one embodiment, the arms 3 and the transverse member 4 form a single-piece assembly. Alternatively, each arm 3 is connected to the transverse member 4 by means of a bearing (not shown in the figures) which allows rotation around the Y axis (by a predetermined angle for example) of the arm 3 relative to the transverse member 4. This makes it possible to absorb part of the vibrations due to the contact of the wheels RI, R2 on the running rails Q1, Q2 and can also limit the rolling effect.

[0054] In this example, the bogie 1 is connected to the chassis CH of the railway vehicle W by the main structure 2.

[0055] According to one aspect of the invention, with reference to Figures 8 to 10, the bogie 1 comprises a first elementary device 5 for orienting the first wheel RL. The elementary orientation device 5 is configured to modify the inclination of the elementary transverse axis YI of the first wheel RI, in the plane (X, Y), so as to incline the elementary plane (XI, Z) of the first wheel RI by rotating it along the vertical axis Z (as shown in [Fig. 10]). In other words, the elementary orientation device 5 is configured to modify the angular position of the first wheel RI along the vertical axis Z, i.e. in the plane (XI, Y1). The first wheel RI thus rotates along its own elementary rotation axis. In other words, the elementary orientation device 5 makes it possible to modify the direction of the elementary transverse axis Y1 (in the plane (X, Y) of the railway vehicle W), which corresponds to the axis of rotation of the first wheel RL

[0056] In a preferred embodiment, the bogie 1 comprises a second elementary device 5 for orienting the second wheel R2. The second elementary device orientation device 5 being configured to modify the inclination of the elementary transverse axis Y2 of the second wheel R2, in the plane (X, Y), so as to incline the elementary plane (X2, Z) of the second wheel R2 along the vertical axis Z (as shown in [Fig. 10]). The second orientation device 5 allows the second wheel R2 to rotate along its own elementary rotation axis. Two elementary orientation devices 5 advantageously make it possible to modify the orientation of each wheel RI, R2 connected to the same main structure 2 of a bogie 1 independently. Thus, the orientation of two wheels RI, R2 can be adapted according to the trajectory of the circulation rail Q1, Q2 on which the wheel RI, R2 circulates.

[0057] Subsequently, for the sake of conciseness and clarity, only the first elementary orientation device 5 will be described, the second elementary orientation device 5 being identical to the first.

[0058] Preferably, the elementary orientation device 5 is mounted between the arm 3 and the wheel RI, R2, so as to locally control the orientation of the wheel RI, R2.

[0059] For this, in a first embodiment, shown in [Fig. 8], the elementary orientation device 5 comprises one (or more) spring member(s) 51 mounted between the arm 3 and the wheel RI, R2. In this example, the elementary orientation device 5 comprises two spring members 51 mounted along the longitudinal axis X in a diametrically opposite manner on the wheel RI, R2, so as to modify the orientation of the wheel RI, R2 along the vertical axis Z.

[0060] In this example, each spring member 51 is passive and is configured to adapt the inclination of the wheel RI, R2 which is then controlled according to the radius of curvature of the railway. In practice, when the wheel RI, R2 travels on a curved portion of railway, the latter is configured to apply a pressure force on the flange B1, B2 of the wheel RI, R2 and to constrain each spring member 51 of the elementary orientation device 5 so as to offset the wheel RI, R2 and allow it to follow the curvature of the railway by limiting the friction between the flange B1, B2 and the head Q11 of the running rail Q1, Q2.

[0061] In a second embodiment, shown in [Fig.9], the elementary orientation device 5 comprises one or more jack(s) 52. In this example, the elementary orientation device 5 comprises two jacks 52 mounted along the longitudinal axis X in a diametrically opposite manner on the wheel RI, R2, so as to modify the orientation of the wheel RI, R2 along the vertical axis Z.

[0062] Preferably, each wheel RI, R2 is mounted on a hub J fixed in rotation and connected to the arm 3 opposite. The wheel RI, R2 is preferably connected to the hub J by a plurality of bearings. The hub J is connected to the arm 3 by means of the jacks 52, the assembly being fixed in rotation relative to the main structure 2 of the bogie 1. In other words, the hub J comprises a support face for the jacks 52 which extends in a plane parallel to the elementary plane (Xi, Y) of the wheel RI, R2.

[0063] The cylinders 52 can be in different forms, for example in the form of a pneumatic, hydraulic or electric cylinder.

[0064] Preferably, each cylinder 52 is controlled so as to impose the inclination of the wheel RI, R2. In an exemplary embodiment, each cylinder 52 is electrically controlled by a computer 9 of the railway vehicle W. In practice, the cylinder 52 is configured to be controlled so as to locally move the wheel RI, R2 to modify its orientation along the vertical axis Z by pushing according to a controlled force. The controlled force can for example be calculated according to a known trajectory of the railway vehicle W and therefore a curvature of the railway track known at a given instant. In this example, when the wheel RI, R2 travels on a curved portion of railway track, each cylinder 52 is controlled to tilt the plane of the hub J causing the inclination of the elementary plane (Xi, Y) of the wheel RI, R2.

[0065] In an alternative embodiment, shown in [Fig. 10], the elementary orientation device 5 comprises a support member 53 connected to the arm 3 and free to rotate relative to the latter. The jacks 52 are mounted on the support member 53 and the assembly of the wheel RI, R2, the jacks 52 and the support member 53 rotates along the transverse elementary axis Yl. The jacks 52 are then defined according to polar coordinates and configured to be continuously controlled so as to ensure that the elementary plane (Xi, Z) of the wheel RI, R2 follows a rotation along the Z axis.

[0066] Two examples are described in which the elementary orientation device 5 comprises two spring members 51 or two jacks 52, it goes without saying that the elementary orientation device 5 could comprise a different number of spring members 51 or jacks 52, in particular a number greater than two. Likewise, it goes without saying that the elementary orientation device 5 could be in a different form, for example in the form of a longitudinal jack system of the rudder type, known to those skilled in the art.

[0067] According to a preferred aspect of the invention, with reference to [Fig. 11] and [Fig. 12], the elementary orientation device 5 is configured to modify the angular position of the first wheel RI along the vertical axis Z in the plane (XI, Y1) up to a maximum angle 0 of between - 10° and 10°. [Fig. 12] shows the example of two elementary orientation devices 5 of the two wheels RI, R2. In particular, [Fig. 12] shows the inclination of the elementary transverse axis Y1 of the first wheel RI in the plane (X, Y) by a first angle 01 and the inclination of the elementary transverse axis Y2 of the second wheel R2 in the plane (X, Y) by a second angle 02. Thanks to the invention, the two elementary transverse axes Y1, Y2 and therefore the two axes of rotation of the two wheels RI, R2 are not collinear and have different directions while being in the plane (X, Y).

[0068] In a preferred embodiment, the bogie 1 comprises a first electric motor M1 (shown in FIGS. 6 and 8 to 11) connected to the first wheel RI and controlled so as to modify the speed of the first wheel RI. More preferably, the bogie 1 comprises a second electric motor M2 connected to the second wheel R2 and controlled so as to modify the speed of the second wheel R2. Each motor M1, M2 thus makes it possible to drive a wheel RI, R2 respectively independently. The two wheels can advantageously be driven at different rotational speeds, which is advantageous in particular on a curved portion of railway track on which the outer wheel R2 travels a greater distance.

[0069] In one embodiment, the bogie 1 comprises a plurality of vertical and transverse suspension members 7 (shown in [Fig.6]) configured to dampen vibrations and / or correct a rolling effect of the railway vehicle W. The suspension members 7 are configured to dampen vibrations along the three axes X, Y, Z of the orthogonal reference frame (X, Y, Z). In this example, the suspension members 7 are in the form of elastic members, for example spring members 51 or shock-absorbing cylinders 52.

[0070] Alternatively or additionally, the suspension members 7 comprise a plurality of damping members 71 (shown in [Fig.6]) configured to adapt the height of the chassis CH of the railway vehicle W to the height of the platform. In other words, the suspension members 7 are configured to adapt the leveling of the chassis CH of the railway vehicle W. In this example, the damping members 71 are in the form of pneumatic elements.

[0071] Preferably, the bogie 1 also comprises a braking device 8 (shown in [Fig.6]) making it possible to control the speed of the wheels RI, R2.

[0072] A method for modifying the orientation of a first wheel RI of a bogie 1 as described above will now be described, according to an embodiment of the invention, with reference to [Fig. 1 1]. It goes without saying that the method applies in a similar manner for modifying the orientation of a second wheel R2 of the bogie. In this example, the bogie 1 comprises a single main structure 2 connected to two wheels RI, R2, however it goes without saying that the method also applies in a similar manner for all the wheels of a bogie 1 comprising two main structures 2, as shown in [Fig. 7]. In this example, the elementary orientation device 5 is in the form of two controllable jacks 52 mounted radially opposite each other on the first wheel RL. In this example also the bogie 1 is connected to the chassis CH of the railway vehicle W by through a pivot link.

[0073] When the railway vehicle W enters a curved portion of railway track, the flange B1 of the outer wheel RI comes into contact with the head Q1 1 of the running rail Q1. The orientation of the bogie 1 is then modified, in a first step E1, relative to the chassis CH of the railway vehicle W. In other words, the orientation of the bogie 1 is offset relative to the longitudinal axis X of the railway vehicle W. In this step, the orientation of the main structure 2 of the bogie 1 is inclined in the horizontal plane (X, Y) along the vertical axis Z by a first angle a of between -10° and 10°.

[0074] In a second step E2, the computer 9 controls, in this example, a modification of the orientation of the first wheel RI by a first orientation angle 01 relative to the arm 3 of the bogie 1, via the elementary orientation device 5. In other words, the elementary transverse axis Y1 of the first wheel RI, corresponding to the axis of rotation of the wheel RI is offset, in this step, along the axis Z, in the plane (X, Y) of the railway vehicle W by the first orientation angle 01. In this example, the elementary transverse axis Y1 of the first wheel RI is inclined by an angle 01 between - 10° and 10°.

[0075] Preferably, the method comprises, simultaneously with the step of modifying the orientation of the first wheel RI, a step consisting of independently modifying the orientation of the second wheel R2 by a second orientation angle 02 relative to the arm 3 of the bogie 1. Thus the two wheels RI, R2 can adapt to different radii of curvature of the two running rails Q1, Q2.

[0076] Alternatively, the orientations of the wheels RI, R2 are carried out passively by the spring members 51 which advantageously allow a calibrated angular movement.

[0077] Thanks to the invention, the articulation of the bogie with the chassis of the railway vehicle makes it possible to adapt the orientation of the bogie to a part of the curvature of the railway track. The elementary orientation device makes it possible, in finishing, to adapt the orientation of the wheel to the curvature of the railway track. Thus, thanks to the invention, the friction of the wheel on the running rail is greatly reduced, which makes it possible to ensure the durability of the wheels of the bogie. In addition, the adaptation of both the rotation speed of each wheel independently and the adaptation of their local orientation with respect to the railway track make it possible, when necessary, to replace only the damaged wheel, without it being necessary to adjust the diameter of all the wheels of the bogie, as was the case in the prior art. In summary, thanks to the invention, the wheels are independent and the defects can be corrected independently.

Claims

Claims

1. Bogie (1) of a railway vehicle (W), the bogie (1) comprising at least one main structure (2) connecting a first wheel (RI) and a second wheel (R2) mounted coaxially with respect to each other, each wheel (RI, R2) extending radially in an elementary plane (Xi, Z) in which the axis (Z) defines a vertical axis (Z), each wheel (RI, R2) being configured to rotate along an elementary transverse axis (Yi) orthogonal to the elementary plane (Xi, Z), the main U-shaped structure (2) comprising two arms (3) and a transverse member (4) connecting the two arms (3), each arm (3) being mechanically connected respectively to a wheel (RI, R2), the main structure (2) being configured to be connected, in an articulated manner along the vertical axis (Z), to a chassis (CH) of the railway vehicle (W) so as to modify the orientation of the bogie (1) relative to the chassis (CH) of the railway vehicle (W),• the bogie (1) being characterized in that it comprises at least one first elementary orientation device (5) for the first wheel (RI), the elementary orientation device (5) being configured to modify the inclination of the elementary transverse axis (Yi) of the first wheel (RI) so as to incline the elementary plane (Xi, Z) of the first wheel (RI) along the vertical axis (Z).,

2. Bogie (1) according to claim 1, comprising a second elementary orientation device (5) for the second wheel (R2), the elementary orientation device (5) being configured to modify the inclination of the elementary transverse axis (Yi) of the second wheel (R2) so as to tilt the elementary plane (Xi, Z) of the second wheel (R2) along the vertical axis (Z), so as to modify the orientation of each wheel (RI, R2) independently.

3. Bogie (1) according to one of claims 1 to 2, in which the elementary orientation device (5) comprises a jack (52) controlled and mounted between the arm (3) and the wheel (RI, R2) connected to said arm (3).

4. Bogie (1) according to one of claims 1 to 2, in which the elementary orientation device (5) comprises a spring member (51) mounted between the arm (3) and the wheel (RI, R2) connected to said arm (3).

5. Bogie (1) according to one of claims 1 to 4, in which the elementary orientation device (5) is configured to modify the angular position of the first wheel (RI) along the vertical axis (Z) in the plane (Xi, Yi) up to a maximum angle of between - 10° and 10°.

6. Bogie (1) according to one of claims 1 to 5, comprising a first electric motor (Ml) connected to the first wheel (RI) and controlled so as to modify the speed of the first wheel (RI).

7. Bogie (1) according to one of claims 1 to 6, comprising a plurality of vertical and transverse suspension members (7) configured to dampen vibrations and / or correct a rolling effect of the railway vehicle (W).

8. Bogie (1) according to one of claims 1 to 7 comprising two main structures (2A, 2B), each main structure (2A, 2B) connecting a first wheel (RI-A, RI-B) and a second wheel (R2-A, R2, B), each main structure (2A, 2B) being mechanically connected to a common connecting member (L) connected to the chassis (CH) of the railway vehicle (W).

9. Railway vehicle (W) comprising a chassis (CH) and at least one bogie (1) according to one of claims 1 to 8, the main structure (2) of the bogie (1) being connected to the chassis (CH) of the railway vehicle (W) and articulated with said chassis (CH) along the vertical axis (Z).

10. Railway vehicle (W) according to claim 9, in which the orientation along the vertical axis (Z) of the main structure (2) relative to the chassis (CH) of the railway vehicle (W) is carried out at a first angle (a) of between - 10° and 10°.

11. Method for modifying the orientation of a first wheel (RI) of a bogie (1) of a railway vehicle (W) according to one of claims 1 to 8, the bogie (1) being mechanically connected to a chassis (CH) of the railway vehicle (W), the method comprises the steps of: • modifying the orientation of the bogie (1) relative to the chassis (CH) of the railway vehicle (1) by a first angle (a), and • independently modifying the orientation of the first wheel (RI) by a first orientation angle (02) relative to the arms (3) of the bogie (1).

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