EP4653284A1

EP4653284A1 - Suspension system for a bogie and associated bogie and vehicle

Info

Publication number: EP4653284A1
Application number: EP24305820.3A
Authority: EP
Inventors: Vincent BETTON
Original assignee: Alstom Holdings SA
Current assignee: Alstom Holdings SA
Priority date: 2024-05-24
Filing date: 2024-05-24
Publication date: 2025-11-26

Abstract

A suspension system (22) for a bogie (10) comprises:
- a torsion bar (32), extending along a main axis (Y2),
- a left fixing bracket (34), and a right fixing bracket (36), both configured to attach the torsion bar to a vehicle chassis (12) and to prevent rotation of the torsion bar about the main axis relative to the vehicle chassis at the respective fixing bracket, and
-a left lever (38) and a right lever (40), both fixed to the torsion bar and located between the left and right fixing brackets, the left and right levers being respectively linked to a left wheel (14) and to a right wheel (16) of the bogie so that the torsion bar suspend the left wheel and the right wheel from the vehicle chassis.

Furthermore, the torsion bar extends continuously between the left fixing bracket and the right fixing bracket.

Description

TECHNICAL FIELD

The present invention concerns a suspension system for a bogie, a bogie comprising such a suspension system and a vehicle comprising such a bogie.

BACKGROUND ART

Railway vehicles are usually mounted on rails through bogies equipped with wheels. A bogie is attached to a chassis of the vehicle, suspending the wheels relative to the vehicle chassis and adapting to the curves encountered as the vehicle travels.
Usually, a bogie comprises wheels and a suspension system to suspend the wheels from the vehicle chassis. Known suspension systems include torsion bar suspension, which use torsion bars, of which one end is attached to the vehicle chassis and the other end is attached to one wheel through a lever.
Torsion bars are usually satisfactory, but are cumbersome, making it difficult to add other components to the bogie.
For example, in a single-axle bogie, i.e. in a bogie with only two wheels, the vehicle chassis is usually compact and the torsion bars takes up much of the available space, preventing the addition of an anti-roll bar to the bogie. An anti-roll bar is a part of a suspension system used to stabilize the vehicle by linking together two wheels located on opposite sides of the vehicle to counteract the rolling moment of the vehicle.
There is therefore a need for an improved suspension system.

SUMMARY OF THE INVENTION

According to one aspect, the invention relates to a suspension system for a bogie, the suspension system being configured to suspend a left wheel and a right wheel of the bogie from a vehicle chassis, the suspension system comprising:

a torsion bar, extending along a main axis,
a left fixing bracket, configured to attach the torsion bar to the vehicle chassis and to prevent rotation of the torsion bar about the main axis relative to the vehicle chassis at the left fixing bracket,
a right fixing bracket, configured to attach the torsion bar to the vehicle chassis and to prevent rotation of the torsion bar about the main axis relative to the vehicle chassis at the right fixing bracket,
a left lever, fixed to the torsion bar, located along the main axis between the left fixing bracket and the right fixing bracket and configured to be linked to the left wheel so that the torsion bar suspend the left wheel from the vehicle chassis, and
a right lever, fixed to the torsion bar, located along the main axis between the left fixing bracket and the right fixing bracket and configured to be linked to the right wheel so that the torsion bar suspend the right wheel from the vehicle chassis.

An advantage of the invention is that the torsion bar is free to rotate about the main axis relative to the vehicle chassis between the left lever and the right lever, so that the torsion bar acts as an anti-roll bar between the left lever and the right lever. Hence, the suspension system of the invention acts simultaneously as a suspension and as an anti-roll bar. This allows, in particular, single-axle bogies to be equipped with an anti-roll bar despite the limited available space.
According to advantageous aspects of the invention, the suspension system may comprise one or more of the following features, considered alone or according to all possible combinations:

The suspension system further comprises at least one rotation free support, each rotation free support being located between the left fixing bracket and the right fixing bracket along the main axis and being configured to attach the torsion bar to the vehicle chassis without preventing rotation of the torsion bar about the main axis relative to the vehicle chassis at the rotation free support.
The at least one rotation free support comprises a left rotation free support and a right rotation free support.
The left lever is located between the left fixing bracket and the left rotation free support along the main axis and wherein the right lever is located between the right fixing bracket and the right rotation free support along the main axis.
The torsion bar extends rectilinearly along the main axis.
The suspension system further comprises at least one secondary torsion bar, extending along a secondary axis, the left wheel and the right wheel being configured to be further suspended from the vehicle chassis by the at least one secondary torsion bar.
The at least one secondary torsion bar comprises a left secondary torsion bar extending along the secondary axis and a right secondary torsion bar extending along the secondary axis, the left wheel being configured to be suspended from the vehicle chassis by the left secondary torsion bar and the right wheel being configured to be suspended from the vehicle chassis by the right secondary torsion bar.
The suspension system further comprises:
- ∘ a left secondary fixing bracket, configured to attach the left secondary torsion bar to the vehicle chassis and to prevent rotation of the left secondary torsion bar about the secondary axis relative to the vehicle chassis at the left secondary fixing bracket,
- ∘ a left secondary lever, fixed to the left secondary torsion bar and configured to be linked to the left wheel so that the left secondary torsion bar suspend the left wheel from the vehicle chassis,
- ∘ a right secondary fixing bracket, configured to attach the right secondary torsion bar to the vehicle chassis and to prevent rotation of the right secondary torsion bar about the secondary axis relative to the vehicle chassis at the right secondary fixing bracket, and
- ∘ a right secondary lever, fixed to the right secondary torsion bar and configured to be linked to the right wheel so that the right secondary torsion bar suspend the right wheel from the vehicle chassis.
The suspension system further comprises:
- ∘ a left secondary rotation free support, configured to attach the left secondary torsion bar to the vehicle chassis without preventing rotation of the left secondary torsion bar about the secondary axis relative to the vehicle chassis at the left secondary rotation free support, the left secondary lever being located between the left secondary fixing bracket and the left secondary rotation free support, along the secondary axis, and
- ∘ a right secondary rotation free support, configured to attach the right secondary torsion bar to the vehicle chassis without preventing rotation of the right secondary torsion bar about the secondary axis relative to the vehicle chassis at the right secondary rotation free support, the right secondary lever being located between the right secondary fixing bracket and the right secondary rotation free support, along the secondary axis.

According to another aspect, the invention also relates to a bogie for a vehicle, the vehicle comprising a chassis, the bogie comprising:

a suspension system as described above,
a left wheel, linked to the left lever and configured to be suspended from the vehicle chassis by the suspension system, and
a right wheel, linked to the right lever and configured to be suspended from the vehicle chassis by the suspension system.

An advantage of the invention is to allow the bogie to benefit from an anti-roll bar without having to add a dedicated anti-roll bar, the suspension system of the invention acting simultaneously as a suspension and as an anti-roll bar.
According to advantageous aspects of the invention, the bogie may comprise one or more of the following features, considered alone or according to all possible combinations:

The left wheel is linked to the left lever through a left link bar of the suspension system, the left link bar being pivotally attached to the left lever, and the right wheel is linked to the right lever through a right link bar of the suspension system, the right link bar being pivotally attached to the right lever.
The main axis is parallel to a rotation axis of the left wheel and of the right wheel.
The bogie is a single-axle bogie.

According to another aspect, the invention also relates to a vehicle comprising a bogie as described above and a vehicle chassis, in which the left wheel and the right wheel are respectively suspended from the vehicle chassis by the suspension system.
An advantage of the invention is to allow the vehicle to benefit from an anti-roll bar without having to add a dedicated anti-roll bar, the suspension system of the invention acting simultaneously as a suspension and as an anti-roll bar. The invention therefore improves the compactness of the bogie and vehicle chassis.
Advantageously, the suspension system further comprises a left secondary torsion bar extending along a secondary axis and a right secondary torsion bar extending along the secondary axis, the left wheel being configured to be suspended from the vehicle chassis by the left secondary torsion bar and the right wheel being configured to be suspended from the vehicle chassis by the right secondary torsion bar. In addition, the vehicle chassis comprises a drawbar located between the left secondary torsion bar and the right secondary torsion bar, along the secondary axis.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and other advantages thereof will appear more clearly upon reading the following description of an exemplary suspension system and an exemplary bogie, provided solely as an example and made in reference to the appended drawings, in which:

[Fig. 1] Figure 1 is a perspective view of a vehicle comprising a bogie integrated under a vehicle chassis, the vehicle and the bogie being according to the invention.
[Fig. 2] Figure 2 is a bottom view of the bogie and vehicle chassis of the vehicle of Figure 1.
[Fig. 3] Figure 3 is a top view of a suspension system of the bogie of Figures 1 and 2, the suspension system being according to the invention.
[Fig. 4] Figure 4 is a top view of a suspension system according to another embodiment of the invention.

DETAILED DESCRITPION OF SOME EMBODIMENTS

An exemplary vehicle V comprising a bogie 10 and a vehicle chassis 12 is illustrated on Figures 1 and 2. The vehicle V is preferably a railway vehicle, such as a tramway or a train. Hence, the vehicle chassis 12 is preferably a railway vehicle chassis.
The bogie 10 is intended to be attached to the vehicle chassis 12. The vehicle V, bogie 10 and vehicle chassis 12 are intended to move along a longitudinal axis X.
The bogie 10 comprises a left wheel 14 and a right wheel 16. In the example, the left and right wheels 14, 16 are independent and can therefore rotate independently of each other about a rotation axis Y1 of the wheels relative to the vehicle chassis 12, the rotation axis Y1 being perpendicular to the longitudinal axis X. When the bogie 10 is moving along the longitudinal axis X, the left wheel 14 is located to the left of the longitudinal axis X and the right wheel 16 is located to the right of the longitudinal axis X, in the direction of movement of the bogie and of the vehicle V.
The bogie comprises a support bar 18, fixed onto the vehicle chassis 12 and on which both left and right wheels 14, 16 are mounted. In the example, the left and right wheels 14, 16 are mounted on the support bar 18 by means of respective hubs 20. Each hub 20 allows for the respective wheel 14, 16 to rotate relative to the support bar 18 and relative to the vehicle chassis 12 about the rotation axis Y1 of the wheels. In Figures 1 and 2, the hubs 20 are represented in simplified form by cylinders.
When the bogie 10 is moving along the longitudinal axis X, the front of the bogie correspond to the portion of the bogie located in front of the support bar 18 and the rear of the bogie correspond to the portion of the bogie located behind the support bar, in the direction of movement of the bogie and of the vehicle V.
As an alternative, not shown, the left and right wheels 14, 16 are connected by an axle so that both wheels and said axle rotate in unison about the rotation axis Y1 relative to the vehicle chassis 12.
The bogie 10 comprises a suspension system 22 to suspend the left wheel 14 and the right wheel 16 from the vehicle chassis 12.
The suspension system 22 comprises a rear part 30 and a front part 60. In the example, the rear part 30 is located in the rear of the bogie 10, and the front part 60 is located in the front of the bogie. As an alternative, not shown, the rear part 30 is located in the front of the bogie 10, and the front part 60 is located in the rear of the bogie.
The rear part 30 of the suspension system 22 is represented alone in Figure 3. The rear part 30 of the suspension system 22 comprises a torsion bar 32, extending along a main axis Y2 parallel to the rotation axis Y1, a left fixing bracket 34 and a right fixing bracket 36. The torsion bar 32 is attached to the vehicle chassis 12 by the left fixing bracket 34 and by the right fixing bracket 36 and each of the left and right fixing bracket prevent rotation of the torsion bar 32 about the main axis Y2 relative to the vehicle chassis 12 at the fixing bracket. In other words, the torsion bar 32 is not free to rotate about the main axis Y2 relative to the vehicle chassis 12 at the left and right fixing brackets 34, 36. In the example, the left and right fixing brackets 34, 36 are positioned at both ends of the torsion bar 32.
The rear part 30 of the suspension system 22 further comprises a left lever 38 and a right lever 40, both of which are fixed to the torsion bar 32 in such a manner that they cannot rotate about the main axis Y2 relative to the torsion bar.
The left lever 38 and the right lever 40 are located, along the main axis Y2, between the left fixing bracket 34 and the right fixing bracket 36.
Preferably, the left and right levers 38, 40 each extend from the torsion bar 32 perpendicular to the torsion bar.
The left lever 38 is linked to the left wheel 14 so that the left wheel is suspended from the vehicle chassis 12 by the rear part 30 of the suspension system 22.
To this end, in the example, the rear part 30 of the suspension system 22 comprises a left link bar 42 and a left fixing plate 44. The left fixing plate 44 is fixed onto the hub 20 associated to the left wheel 14. A first extremity of the left link bar 42 is pivotally attached to the left fixing plate 44 and the other extremity of the left link bar 42 is pivotally attached to the left lever 38. Hence, the left wheel 14 is linked to the left lever 38 by the left link bar 42 and the left fixing plate 44. Furthermore, a displacement of the left wheel 14 perpendicular to the rotation axis Y1 and perpendicular to the longitudinal axis X results in a shift of the left link bar 42, causing a rotation of the left lever 38 about the main axis Y2 and thus a rotation of the torsion bar 32 about the main axis Y2 at the left lever, relative to the vehicle chassis 12. In other words, the left lever 38 receives the forces applied to the left wheel 14 perpendicularly to the rotation axis Y1 and to the longitudinal axis X and converts them into a rotation of the torsion bar 32 about the main axis Y2 relative to the vehicle chassis 12.
Similarly, the right lever 40 is linked to the right wheel 16 so that the right wheel is suspended from the vehicle chassis 12 by the rear part 30 of the suspension system 22. To this end, in the example, the rear part 30 of the suspension system 22 comprises a right link bar 46 and a right fixing plate 48, which are similar respectively to the left link bar 42 and to the left fixing plate 44 and work in the same way.
In Figures 1 and 2, the fixation of the left and right fixing plates 44, 48 are represented in a simplified way.
As an alternative, not shown, other means to link the left wheel 14 to the left lever 38 and to link the right wheel 16 to the right lever 40 can be considered.
Thanks to the torsion bar 32, the left fixing bracket 34 and the left lever 38, the left wheel 14 is suspended to the vehicle chassis 12 of the vehicle V. Indeed, a displacement of the left wheel 14 perpendicular to the rotation axis Y1 and perpendicular to the longitudinal axis X results in a rotation of the torsion bar 32 about the main axis Y2 at the left lever 38, relative to the vehicle chassis 12, as explained above. As the torsion bar 32 is fixed to the vehicle chassis 12 by the left fixing bracket 34, this rotation of the torsion bar at the left lever 38 results in a twisting of the torsion bar 32 about the main axis Y2 between the left lever and the left fixing bracket, relative to the vehicle chassis 12. This twisting of the torsion bar 32 is resisted by the torsion resistance of the torsion bar, i.e. by its stiffness, and therefore the torsion bar 32 opposes the displacement of the left wheel 14.
Similarly, thanks to the torsion bar 32, the right fixing bracket 36 and the right lever 40, the right wheel 16 is suspended to the vehicle chassis 12 of the vehicle V.
In addition, the positioning of the left and right levers 38, 40, between the left and right fixing brackets 34, 36 is particularly advantageous as it allows the portion of the torsion bar 32 between the left and right levers 38, 40 to act as an anti-roll bar.
Indeed, the torsion bar 32 is free to rotate about the main axis Y2 relative to the vehicle chassis 12 between the left and right levers 38, 40 as the left and right fixing brackets 34, 36 are not located between the left and right levers.
Therefore, an identical displacement of the left wheel 14 and the right wheel 16 perpendicular to the rotation axis Y1 and perpendicular to the longitudinal axis X simply results in a rotation of the torsion bar 32 about the main axis Y2 relative to the vehicle chassis 12 between the left lever 38 and the right lever 40, because the rotation of the left and right levers 38, 40 about the main axis Y2 are identical.
On the contrary, when the two wheels 14, 16 undergo different displacement perpendicular to the rotation axis Y1 and perpendicular to the longitudinal axis X, then the left and right levers 38, 40 rotate differently about the main axis Y2, relative to the vehicle chassis 12, resulting in a torsion, i.e. a twist, of the torsion bar about the main axis Y2 between the left and right levers. This twisting of the torsion bar 32 is resisted by the torsion resistance of the torsion bar, i.e. by its stiffness, and therefore the torsion bar 32 opposes the different rotation of the left and right levers and thus the different displacement of the left and right wheels. In other words, the torsion bar 32 opposes rotation of the left lever 38 relative to the right lever 40 about the main axis Y2. As a result, both left and right wheels 14, 16 to tend to undergo the same displacement perpendicular to the rotation axis Y1 and perpendicular to the longitudinal axis X, thereby reducing the body roll of the bogie 10.
Hence, the rear portion 30 of the suspension system 22 acts simultaneously as a suspension for both left and right wheels 14, 16 and as an anti-roll bar opposing the body roll of the bogie 10. More precisely, the two extremities of the torsion bar 32, between the levers 38, 40 and the respective fixing brackets 34, 36, act as suspension for the left and right wheels 14, 16 and the centre of the torsion bar, between the two levers 38, 40, acts as an anti-roll bar.
This dual function of the rear portion 30 of the suspension system 22, and more specifically of the torsion bar 32, is particularly advantageous as it allows to benefit from an anti-roll bar without needing more available space, thus allowing the bogie 10 to be more compact. In particular, this dual function of the rear portion 30 of the suspension system 22 is made possible by the fact that the torsion bar 32 extends continuously between the left fixing bracket 34 and the right fixing bracket 36 and by the fact that the torsion bar 32 is free to rotate about the main axis Y2 relative to the vehicle chassis 12 between the left lever 38 and the right lever 40.
Advantageously, the left lever 38 and the right lever 40 each comprise a fixation hole 49, which allows for the fixation of a shock absorber between the lever and the vehicle chassis 12 to improve the performances of the suspension system 22.
Advantageously, the rear portion 30 of the suspension system 22 further comprises a left rotation free support 50 and a right rotation free support 52. Both left and right rotation free supports 50, 52 are located between the left fixing bracket 34 and the right fixing bracket 36, along the main axis Y2.
Each rotation free support 50, 52 is configured to attach the torsion bar 32 to the vehicle chassis 12 without preventing rotation of the torsion bar about the main axis Y2 relative to the vehicle chassis at the rotation free support. Thus, the rotation free supports 50, 52 do not affect the rotation or torsion of the torsion bar 32 about the main axis Y2 and therefore do not affect the operation of the torsion bar 32 as a suspension of the wheels 14, 16 and as an anti-roll bar.
The rotation free supports 50, 52 prevent the torsion bar 32 from moving perpendicularly to the main axis Y2 at the rotation free supports as a result of the torsion of the torsion bar. This prevents flexion of the torsion bar, i.e. this prevents the torsion bar from bending. Hence, the torsion bar 32 can only be deformed in torsion. The reliability of the torsion bar 32 is thus increased, as a flexion of the torsion bar could negatively affect its operation.
Preferably, the left lever 38 is located between the left fixing bracket 34 and the left rotation free support 50 and the right lever 40 is located between the right fixing bracket 36 and the right rotation free support 52.
As a variant, shown in Figure 4, the left lever 38 and the right lever 40 are located between the right rotation free support 52 and the left rotation free support 50. This variant can be used when it is not possible to integrate the right rotation free support 52 and the left rotation free support 50 between the left lever 38 and the right lever 40, for reasons of compactness or because of other constraints on the vehicle chassis 12.
As a variant, not shown, the rear portion 30 of the suspension system 22 comprises only one rotation free support, preferably located in the middle of the torsion bar 32, between the left and right levers 38, 40, or more than two rotation free supports.
In the example, the torsion bar 32 is straight, so that the left fixing bracket 34, the right fixing bracket 36, the left lever 38, the right lever 40, the left rotation free support 50 and the right rotation free support 52 are all arranged on the main axis Y2, i.e. are all aligned along the main axis Y2. In other words, the torsion bar 32 extends rectilinearly along the main axis Y2 between the left fixing bracket 34 and the right fixing bracket 36.
Advantageously, the front part 60 of the suspension system 22 comprises a left secondary torsion bar 62 and a right secondary torsion bar 64, each extending along a common secondary axis Y3 parallel to the main axis Y2. Hence, the rotation axis Y1, the main axis Y2 and the secondary axis Y3 are all parallel. The left wheel 14 is further suspended from the vehicle chassis 12 by the left secondary torsion bar 62 and the right wheel 16 is further suspended from the vehicle chassis 12 by the right secondary torsion bar 64.
The front part 60 of the suspension system 22 further comprises a left secondary fixing bracket 66, attaching the left secondary torsion bar 62 to the vehicle chassis 12 and preventing rotation of the left secondary torsion bar 62 about the secondary axis Y3 relative to the vehicle chassis 12 at the left secondary fixing bracket 66.
The front part 60 of the suspension system 22 further comprises a left secondary lever 68, fixed to the left secondary torsion bar 62 and linked to the left wheel 14. In the example, the left wheel 14 is linked to the left secondary lever 68 with a left secondary link bar 70 and a left secondary fixing plate 72, which operate similarly to the left link bar 42 and the left fixing plate 44 previously described.
Hence, thanks to the left secondary fixing bracket 66 and to the left secondary lever 68, the left secondary torsion bar 62 operates as a suspension to suspend the left wheel 14 from the vehicle chassis 12. Practically speaking, the operation of the left secondary torsion bar 62 as a suspension of the left wheel 14 is similar to the operation of the torsion bar 32 as a suspension of the left wheel.
Preferably, the front part 60 of the suspension system 22 further comprises a left secondary rotation free support 74, through which the left secondary torsion bar 62 is attached to the vehicle chassis 12 without preventing rotation of the left secondary torsion bar about the secondary axis Y3 relative to the vehicle chassis 12 at the left secondary rotation free support 74. The left secondary lever 68 is located between the left secondary fixing bracket 66 and the left secondary rotation free support 74, along the secondary axis Y3. Hence, the left secondary rotation free support 74 prevents flexion of the left secondary torsion bar 62, which can therefore only be deformed in torsion.
Similarly, the front part 60 of the suspension system 22 further comprises a right secondary fixing bracket 76, a right secondary lever 78, a right secondary link bar 80 and a right secondary fixing plate 82, with which the right wheel 16 is linked to the right secondary torsion bar 64 so that the right wheel is suspended from the vehicle chassis 12.
Hence, thanks to the right secondary fixing bracket 76 and to the left secondary lever 78, the right secondary torsion bar 64 operates as a suspension to suspend the right wheel 16 from the vehicle chassis 12. Practically speaking, the operation of the right secondary torsion bar 64 as a suspension of the right wheel 16 is similar to the operation of the torsion bar 32 as a suspension of the right wheel.
Preferably, the front part 60 of the suspension system 22 further comprises a right secondary rotation free support 84, which operates similarly to the left secondary rotation free support 74.
As an alternative, not shown, other means to link the left wheel 14 to the left secondary lever 68 and to link the right wheel 16 to the right secondary lever 78 can be considered.
The front part 60 of the suspension system 22 therefore comprises two torsion bars 62, 64, each torsion bar being dedicated to the suspension of one of the left and right wheels 14, 16 from the vehicle chassis 12. The use of two torsion bars, instead on a common torsion bar to suspend both the left and right wheels 14, is particularly advantageous as it allows freeing space between the two torsion bars, along the secondary axis Y3, as visible in Figures 1 and 2.
In the example, said free space allows the vehicle chassis 12 of the vehicle V to further comprises a drawbar 90. The drawbar 90 is pivotally attached to the vehicle chassis 12 and is intended to attach the vehicle V to another vehicle to which the same type of bogie 10 is attached, said another bogie preceding the bogie 10 along the longitudinal axis X, in the direction of movement of the bogie 10.
As an alternative, not shown, instead of the left and right secondary torsion bar 62, 64, the front part 60 of the suspension system 22 comprises only a secondary torsion bar, with which the left and right wheels 14, 16 are both suspended to the vehicle chassis 12, preferably through respective levers.
As an alternative, not shown, the suspension system 22 only comprises the rear part 30 and do not comprises the front part 60.
In the example, the bogie 10 is a single-axle bogie, i.e. only comprises one pair of wheels 14, 16. As an alternative, not shown, the bogie 10 is a multi-axle bogie, having more than one pair of wheels. In such alternative, at least one pair of wheels, and preferably all pairs of wheels, are suspended to the vehicle chassis 12 with a suspension system 22 as described above.
In the example, the vehicle V is a railway vehicle. As an alternative, not shown, the vehicle is another type of vehicle, such as a tracked vehicle or a wheeled vehicle. Indeed, the suspension system 22 of the invention can also be used in other vehicles, such as in tracked vehicles or in wheeled vehicles, for example in trucks. In particular, the suspension system 22 of the invention can be used to suspend a truck wheelset, or axle, to a truck chassis.
The relative terms "left" and "right" are used herein to describe a relationship of one component of the bogie 10 to another component of the bogie relative to the longitudinal axis X, as illustrated in Figures 1 to 3. It will be understood that these terms are intended to encompass different orientations of the bogie 10 and its components in addition to the orientation depicted in the Figures.
The features of the embodiment and variants considered in this description can be combined to generate new embodiments of the invention, within the framework of the appended set of claims.

Claims

A suspension system (22) for a bogie (10), the suspension system (22) being configured to suspend a left wheel (14) and a right wheel (16) of the bogie (10) from a vehicle chassis (12), the suspension system (22) comprising:
- a torsion bar (32), extending along a main axis (Y2),

- a left fixing bracket (34), configured to attach the torsion bar (32) to the vehicle chassis (12) and to prevent rotation of the torsion bar about the main axis (Y2) relative to the vehicle chassis (12) at the left fixing bracket (34),

- a right fixing bracket (36), configured to attach the torsion bar (32) to the vehicle chassis (12) and to prevent rotation of the torsion bar about the main axis (Y2) relative to the vehicle chassis (12) at the right fixing bracket (36),

- a left lever (38), fixed to the torsion bar (32), located along the main axis (Y2) between the left fixing bracket (34) and the right fixing bracket (36) and configured to be linked to the left wheel (14) so that the torsion bar (32) suspend the left wheel (14) from the vehicle chassis (12), and

- a right lever (40), fixed to the torsion bar (32), located along the main axis (Y2) between the left fixing bracket (34) and the right fixing bracket (36) and configured to be linked to the right wheel (16) so that the torsion bar (32) suspend the right wheel (16) from the vehicle chassis (12),
wherein the torsion bar (32) extends continuously between the left fixing bracket (34) and the right fixing bracket (36).
The suspension system (22) of claim 1, further comprising at least one rotation free support (50, 52), each rotation free support (50, 52) being located between the left fixing bracket (34) and the right fixing bracket (36) along the main axis (Y2) and being configured to attach the torsion bar (32) to the vehicle chassis (12) without preventing rotation of the torsion bar about the main axis (Y2) relative to the vehicle chassis (12) at the rotation free support (50, 52).
The suspension system (22) of claim 2, wherein the at least one rotation free support (50, 52) comprises a left rotation free support (50) and a right rotation free support (52).
The suspension system (22) of claim 3, wherein the left lever (38) is located between the left fixing bracket (34) and the left rotation free support (50) along the main axis (Y2) and wherein the right lever (40) is located between the right fixing bracket (36) and the right rotation free support (52) along the main axis (Y2).
The suspension system (22) of any one of claims 1 to 4, wherein the torsion bar (32) extends rectilinearly along the main axis (Y2).
The suspension system (22) of any one of claims 1 to 5, further comprising at least one secondary torsion bar (62, 64), extending along a secondary axis (Y3), the left wheel (14) and the right wheel (16) being configured to be further suspended from the vehicle chassis (12) by the at least one secondary torsion bar (62, 64).
The suspension system (22) of claim 6, wherein the at least one secondary torsion bar (62, 64) comprises a left secondary torsion bar (62) extending along the secondary axis (Y3) and a right secondary torsion bar (64) extending along the secondary axis (Y3), the left wheel (14) being configured to be suspended from the vehicle chassis (12) by the left secondary torsion bar (62) and the right wheel (16) being configured to be suspended from the vehicle chassis (12) by the right secondary torsion bar (64).
The suspension system (22) of claim 7, further comprising:
- a left secondary fixing bracket (66), configured to attach the left secondary torsion bar (62) to the vehicle chassis (12) and to prevent rotation of the left secondary torsion bar about the secondary axis (Y3) relative to the vehicle chassis (12) at the left secondary fixing bracket (66),

- a left secondary lever (68), fixed to the left secondary torsion bar (62) and configured to be linked to the left wheel (14) so that the left secondary torsion bar (62) suspend the left wheel from the vehicle chassis (12),

- a right secondary fixing bracket (76), configured to attach the right secondary torsion bar (64) to the vehicle chassis (12) and to prevent rotation of the right secondary torsion bar about the secondary axis (Y3) relative to the vehicle chassis (12) at the right secondary fixing bracket (76), and

- a right secondary lever (78), fixed to the right secondary torsion bar (64) and configured to be linked to the right wheel (16) so that the right secondary torsion bar (64) suspend the right wheel from the vehicle chassis (12).
The suspension system of claim 8, further comprising:
- a left secondary rotation free support (74), configured to attach the left secondary torsion bar (62) to the vehicle chassis (12) without preventing rotation of the left secondary torsion bar about the secondary axis (Y3) relative to the vehicle chassis (12) at the left secondary rotation free support (74), the left secondary lever (68) being located between the left secondary fixing bracket (66) and the left secondary rotation free support (74), along the secondary axis (Y3), and

- a right secondary rotation free support (84), configured to attach the right secondary torsion bar (64) to the vehicle chassis (12) without preventing rotation of the right secondary torsion bar about the secondary axis (Y3) relative to the vehicle chassis (12) at the right secondary rotation free support (84), the right secondary lever (78) being located between the right secondary fixing bracket (76) and the right secondary rotation free support (84), along the secondary axis (Y3).
A bogie (10) for a vehicle (V), the vehicle comprising a chassis (12), the bogie (10) comprising:
- a suspension system (22) according to any one of claims 1-9,

- a left wheel (14), linked to the left lever (38) and configured to be suspended from the vehicle chassis (12) by the suspension system (22), and

- a right wheel (16), linked to the right lever (40) and configured to be suspended from the vehicle chassis (12) by the suspension system (22),

wherein the torsion bar (32) is configured to be free to rotate about the main axis (Y2) relative to the vehicle chassis (12) between the left lever (38) and the right lever (40),

and wherein the torsion bar (32) is configured to oppose rotation of the left lever (38) relative to the right lever (40) about the main axis (Y2).
The bogie (10) of claim 10, wherein the left wheel (14) is linked to the left lever (38) through a left link bar (42) of the suspension system (22), the left link bar (42) being pivotally attached to the left lever (38), and wherein the right wheel (16) is linked to the right lever (40) through a right link bar (46) of the suspension system (22), the right link bar (46) being pivotally attached to the right lever (40).
The bogie (10) of any one of claims 10 or 11, wherein the main axis (Y2) is parallel to a rotation axis (Y1) of the left wheel (14) and of the right wheel (16).
The bogie (10) of any one of claims 10 to 12, wherein the bogie (10) is a single-axle bogie.
A vehicle (V) comprising a bogie (10) according to any one of claims 10 to 13 and a vehicle chassis (12), wherein the left wheel (14) and the right wheel (16) are respectively suspended from the vehicle chassis (12) by the suspension system (22).
The vehicle of claim 14, the suspension system (22) further being according to any one of claims 7 to 9, wherein the vehicle chassis (12) comprises a drawbar (90) located between the left secondary torsion bar (62) and the right secondary torsion bar (64), along the secondary axis (Y3).