TWO-AXLE RAILWAY VEHICLE SUSPENSION
Patent Information
- Application Number
- FR2020014177
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2020-12-28
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2040-12-28
Smart Images
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Abstract
Description
Title of the invention: SUSPENSION FOR TWO-AXLE RAIL VEHICLE Technical field
[0001] The present invention relates to the field of two-axle light rail vehicles.
[0002] The invention relates more particularly to an assembly comprising an axle and a connecting device provided for connecting said axle to the chassis of a railway vehicle, which assembly is capable of running this vehicle on very degraded, winding railway tracks and / or tracks having sharp bends. Prior art
[0003] Nowadays, the rehabilitation of small railway lines, which are generally found in suburban and rural areas and which have not been used for a long time, is being considered.
[0004] However, in addition to being generally winding and having sharp bends, due to a lack of maintenance or abandonment, these secondary tracks are often in a state that does not allow the circulation of existing railway vehicles: lack of ballast, significant left-hand track, degraded clothoid, etc.
[0005] However, bringing these railway lines up to standard and maintaining them regularly represents too high a cost to imagine reopening them for conventional railway vehicles.
[0006] Also, rather than renovating these tracks, there is a need for railway vehicles capable of running on these very degraded railway lines.
[0007] In order to travel on inconvenient railway lines, in the 1950s in Germany, a new railway vehicle was developed: the Schienenbus. This was a railcar carried by only two axles and not by bogies, which made it a light vehicle, 10 tonnes per axle, and low energy consumption.
[0008] The suspension of this vehicle was conventionally made with leaf springs such as those used for two-axle freight wagons.
[0009] However, this suspension had many drawbacks:
[0010] • It did not filter track defects sufficiently.
[0011] • It made the vehicle uncomfortable and noisy, among other things, due to the rise of the solid noises and squeals in the curves.
[0012] • It was susceptible to derailment on tight curves, requiring sharply reduce the vehicle's speed.
[0013] • It generated stresses and wear on the track in tight curves.
[0014] Since this type of suspension is not very advantageous, there is therefore a need for a new connection assembly capable of equipping a light railway vehicle which is carried by only two axles and which does not have the disadvantages of the Schienenbus suspension or other existing suspensions for railway vehicles.
[0015] Furthermore, the new railway vehicle assembly must provide interior comfort equivalent to that experienced in modern trams, while being robust, simple, inexpensive and reliable.
[0016] It is also very important that the new railway vehicle assembly ensures good guidance of the vehicle, regardless of the state of deterioration of the tracks, including on winding tracks and / or tracks with sharp bends.
[0017] To ensure the guidance of a railway vehicle on the rails, the rolling profile of the wheels is slightly conical in shape with a concave connection towards the flange. It is the shape of each wheel within a railway axle, by the difference in the right-left, inside-outside rolling radii, which allows the axle to self-center on the track when it moves laterally, without the action of external organs. This mechanical control allows the axle of a railway vehicle to take wide curves without wearing its flange, which is called the "bicone effect". The conicity, that is to say the average angle at wheel-rail contact is specific to each "wheel profile / rail profile" pair.
[0018] A high conicity is characterized by a contact capable of self-orienting the axle well, but it tends to make the axle, and therefore the vehicle, unstable. High conicity torques are usually used for winding networks, and low conicity torques for high-speed trains.
[0019] For tracks with medium curves, with a radius of curvature greater than 350 meters, the bicone effect is generally sufficient to allow the axle to orient itself correctly and the lateral forces on the flanges remain low, which preserves the track and the wheels.
[0020] In the case of sharp curves, where the radius of curvature is less than 350 meters and can be up to 150 meters, the bicone effect is insufficient. Also, in the case of the new assembly for a two-axle railway vehicle, it must advantageously allow the axle to take a drift angle - also known as yaw orientation - relative to the chassis so as not to overly hinder its self-orientation and to absorb transverse stresses. It must also have sufficient yaw stiffness to ensure the intrinsic stability and comfort necessary for passenger transport, particularly when the axle comes into contact with track defects.
[0021] The new assembly must allow lateral movements in order to filter lateral stresses generated by rolling and track defects. Similarly, this The new assembly must allow for axle parallelism, particularly in a straight line. Poorly controlled parallelism is likely to result in a permanent axle drift angle and cause premature wear of the wheels or tracks, or even derailment of the vehicle.
[0022] The new assembly must also allow individually adjustable stiffness along the vertical axis for each of the two wheels of the same axle, such a pendulum assembly advantageously making it possible to ensure a natural frequency independent of their strong load variation.
[0023] Ideally, the new assembly should also allow at least one wheel of the axle to be moved vertically and actively relative to the chassis of the railway vehicle in order to tilt the railway vehicle when cornering for greater passenger comfort.
[0024] Finally, the new assembly's mounts should advantageously be positioned outside the wheels to improve roll resistance. Presentation of the invention
[0025] The object of the present invention is therefore to overcome the drawbacks of the prior art by proposing a new light railway vehicle, for example of the railcar type, which is carried by only two axles, and not bogies. This vehicle, with a maximum load of 25 tonnes, is considered light when compared to conventional railway vehicles carried by only two bogies, and generally weighing close to 50 tonnes.
[0026] This light railway vehicle is characterized by a new assembly comprising an axle equipped with two wheels and at least one connecting device provided for connecting said axle to the chassis of a railway vehicle, characterized in that the axle is capable of pivoting relative to said chassis around a substantially vertical axis and in that the connecting device comprises the following means: • a control actuator comprising a body and a movable part, the body of said control actuator being intended to be connected to the chassis of the vehicle;
[0027] • a control rod, a first end of which is mounted by a articulation at the free end of the movable part of the control actuator, while its second end is mounted by another articulation on the chassis of the vehicle;
[0028] • a suspension arm carrying a lateral end of the axle, a first end of said suspension arm being mounted articulated to the control rod by a joint; and
[0029] • a suspension device comprising at least one suspension provided between the vehicle chassis and suspension arm to suspend and cushion vertical movements;
[0030] these means being arranged so that when the control rod is pivoted by the control actuator, the axle pivots relative to the chassis around a substantially vertical axis.
[0031] The control actuator, via the control rod, advantageously makes it possible to force the yaw orientation of the axle, or even to force the lateral inclination of the chassis relative to the track. The control actuator modifies the drift angle between the axle and the chassis by moving the articulation point of the suspension arm relative to the chassis or relative to the axle.
[0032] Thus, the translational movement of the movable part of the actuator causes the control rod to pivot in a substantially vertical plane so as to drive the articulation of the suspension arm forwards or backwards in the general longitudinal direction of the vehicle, which advantageously leads to a yaw movement of the axle.
[0033] Similarly, advantageously, the movement of the actuator part also causes the control rod to pivot in a substantially vertical plane so as to drive the articulation of the suspension arm upwards or downwards, which laterally tilts the chassis of the vehicle relative to the axle and makes it possible to give the chassis some heel in curves and to compensate for centrifugal effects.
[0034] Advantageously, the suspension device dampens the vertical displacement of the chassis relative to the axle and provides vertical comfort. It also makes it possible to locally compensate for the load state of the vehicle in order to adjust the height of the vehicle chassis relative to the axle.
[0035] According to an exemplary implementation of the invention, the articulation of the suspension arm is an elastic articulation provided to allow, with a determined stiffness, vertical movements, lateral movements and rolling movements of the chassis of the vehicle relative to the suspension arm, and to allow the yaw orientation of the axle in curves.
[0036] According to another example of implementation of the invention, the articulation of the suspension arm comprises an elastomer part, preferably of the rubber type or rubber-metal composite type, and preferably heterogeneous to obtain different stiffnesses in x, y and z.
[0037] According to an additional example of implementation of the invention, the amplitude of the vertical, lateral and rolling movements permitted by the articulation of the suspension arm are less than 10 millimeters, preferably less than 8 millimeters and more preferably less than 5 millimeters.
[0038] According to an exemplary implementation of the invention, the stiffness of the articulation of the suspension arm in x, y and z is between 2 x 105 N / m and 2 x 107 N / m, preferably between 7 x 105 N / m and 7 x 106 N / m and more preferably between 1 x 106 N / m and 5 x 106 N / m.
[0039] According to an exemplary implementation of the invention, the suspension arm extends substantially horizontally along the longitudinal axis of the railway vehicle so that, when the connecting rod is pivoted by the control actuator and exerts a force on the suspension arm at the articulation, the kinematics of this connecting rod generates a vertical force component and laterally tilts the chassis of the railway vehicle relative to the track.
[0040] According to another example of implementation of the invention, the suspension arm is provided under the chassis and on the outside of the wheel associated with it. Indeed, the fact of separating the suspensions as much as possible improves the roll resistance of the railway vehicle.
[0041] According to an additional example of implementation of the invention, the control rod extends substantially vertically so that, when the control rod is pivoted by the control actuator and exerts a force on the suspension arm at the articulation, the kinematics of this rod generates a horizontal force component and orients the axle in yaw.
[0042] According to an exemplary implementation of the invention, the control actuator extends substantially horizontally along the longitudinal axis of the railway vehicle so as to pivot the control rod in a vertical plane when the movable part of said control actuator is moved.
[0043] According to another example of implementation of the invention, the articulation of the suspension arm is preferably provided between the two articulations of the control rod, and more preferably in the substantially middle part of the control rod so that the point of application of the forces exerted by the control actuator on the control rod at the level of the first articulation thereof is distant from said first end of the control rod.
[0044] Thus, the stroke of the actuator is amplified, which simplifies its control and the force of the forces exerted by the control actuator on the control rod at the first articulation of the latter is increased and greater at the articulation of the suspension arm, so that the force exerted by the control actuator is amplified at the articulation of the suspension arm.
[0045] According to an additional example of implementation of the invention, the axle is connected to the suspension arm, between the first and second ends of said suspension arm, preferably at the level of the substantially median part of said suspension arm so that the point of application of the forces exerted by the control rod on the suspension arm at the level of the articulation is distant from the lateral end of the axle carried by said suspension arm.
[0046] In fact, the suspension arm is said to be pulled:
[0047] - it is articulated at its end;
[0048] - it is connected to the axle in the middle part of the latter; and
[0049] - it is connected to the body by the suspension device on the opposite side.
[0050] The position of the axle connection is chosen so as to distribute the loads taken up by the articulation and the suspension. The aim is to reduce the loads on the articulation so that these loads are exerted as much as possible on the suspension. Thus, comfort is better and the fatigue resistance of the connection device is improved.
[0051] According to an exemplary implementation of the invention, the suspension of the suspension device is a pneumatic spring, preferably comprising a diaphragm or a bellows capable of being inflated with compressed air.
[0052] According to another example of implementation of the invention, the new assembly according to the invention comprises a sensor between the axle and the chassis of the vehicle, this sensor being provided to measure the load state of the vehicle and regulate the pressure of the compressed air supplied to the pneumatic suspension as a function of said load state.
[0053] According to an additional example of implementation of the invention, the suspension device comprises a substantially vertical or inclined shock absorber of the hydraulic, oleopneumatic or hydropneumatic type.
[0054] This pneumatic shock absorber is advantageously provided with a stiffness making it possible to obtain a natural frequency of the suspension of the order of Hertz, to provide vertical comfort.
[0055] Indeed, a suspension usually includes a spring element and a shock absorber, generally hydraulic, to dampen and prevent the spring from pumping. With a hydraulic suspension, for example, it is possible to combine the spring and the shock absorber in the same component. With an air suspension, preferred in the railway sector, a hydraulic telescopic shock absorber is generally added which calms the oscillations of the air spring by rolling oil, therefore by heat.
[0056] According to an exemplary implementation of the invention, the part of the control rod comprising the articulation provided in its second end is inclined longitudinally towards the center of the chassis at an angle between 10° and 65°, preferably between 20° and 55°, and more preferably between 30° and 45° relative to the vertical.
[0057] According to an exemplary implementation of the invention, the articulation of the control rod on the chassis is an elastic articulation provided to allow, with a determined stiffness, at least lateral movements of the control rod relative to the chassis.
[0058] According to another additional example of implementation of the invention, the assembly according to the invention comprises a lateral damping device provided to connect the axle to the chassis so as to dampen the lateral stresses generated by the axle and transmitted to the chassis.
[0059] According to an additional example of implementation of the invention, the lateral damping device comprises two dampers provided one behind the other and symmetrically with respect to the median longitudinal axis of the vehicle.
[0060] According to an exemplary implementation of the invention, the control actuator is a hydraulic cylinder, which advantageously allows the control actuator, which has become passive in the event of a breakdown, to fulfill the role of a yaw damper to guarantee satisfactory stability of the vehicle. Brief description of the drawings
[0061] Other characteristics and advantages of the present invention will appear more clearly on reading the description which follows, given with reference to the appended drawings, given as non-limiting examples, in which:
[0062] [Fig-1] [Fig. 1] is a plan view from above illustrating a part of the chassis of a railway vehicle comprising an axle equipped with two suspensions according to the invention.
[0063] [Fig.2] [Fig.2] is a perspective view from below illustrating part of chassis similar to that of [Fig.l].
[0064] [Fig.3] [Fig.3] is a perspective view from above illustrating a chassis portion similar to that of Figures 1 and 2 and in which the control rod is in the form of a single, slightly curved plate.
[0065] [Fig.4] [Fig.4] is a perspective view similar to that of [Fig.3], in in which the chassis of the railway vehicle is not shown.
[0066] [Fig.5] [Fig.5] is a perspective view from above illustrating a chassis portion similar to that of Figures 1 and 2, in which the control rod is in the form of two parallel, non-curved flanks.
[0067] [Fig.6] [Fig.6] is a detail view of [Fig.5] at the level of the device of connection.
[0068] [Fig.7] [Fig.7] is a side view illustrating a chassis portion similar to that of figures 1 and 2 and in which the control rod is curved.
[0069] [Fig.8] [Fig.8] is a side view illustrating a similar chassis portion to that of figures 1 and 2, in which the chassis of the railway vehicle is not shown and in which the control rod is substantially rectilinear.
[0070] [Fig.9] [Fig.9] is a perspective view of the elastic joint of the arm of suspension.
[0071] [Fig. 10] [Fig. 10] is a sectional view of the elastic joint of the suspension arm of [Fig.9] along the section axis XX. Detailed description
[0072] Structurally and functionally identical elements present in several distinct figures are assigned the same numerical or alphanumeric reference.
[0073] By vertical or horizontal, we will refer to the vehicle when it is in normal conditions of use on flat and non-inclined ground. By longitudinal we will therefore understand the general axis of the vehicle along which it moves, an axis which is the same as that of the track in the case where the latter is straight. Similarly, by horizontal plane, we mean the average plane in which the vehicle is located, a plane which is parallel to that comprising the two rails of the track in the case where the latter is straight, flat and non-inclined. Furthermore, by vertical axis, we mean an axis which is perpendicular to the horizontal plane previously defined. Finally, by transverse, we mean a direction or an axis which extends horizontally and perpendicularly to the longitudinal axis of the vehicle.
[0074] The new assembly according to the invention is preferably intended to equip a new light railway vehicle, with a maximum load of 25 tonnes, which is carried by only two axles (2), and not by bogies. Said assembly comprises an axle (2) equipped with two wheels (3) and at least one connecting device (1) provided to connect said axle (2) to the chassis (9) of a railway vehicle
[0075] Conventionally, each axle (2) comprises a railway wheel (3) at each of its ends.
[0076] In the new light rail vehicle, for example of the railcar type, the motorization is provided by at least one electric motor (4) which is preferably fixed to the chassis (9), but which can also be fixed to at least one axle (2). Preferably, each axle (2) thus motorized carries in its center a reducer (5), for example of the bevel gear type with a reduction ratio defined according to the expected performances. The crown of the reducer (5) is linked in rotation to the axle (2), while the casing (6) which carries the input pinion of the reducer (5) is mounted free in rotation relative to the axle (2) which transmits the torques to the wheels (3). The casing (6) of the reducer (5) is for example suspended from the chassis (9) of the railway vehicle by a suspension device (34) comprising for example two upper (23) and lower (24) connecting rods which hold it in rotation. Each electric motor (4) is preferably fixed under the body, and the mechanical connection (7) between the electric motor (4) and the axle (2) associated with it is preferably a homokinetic transmission, for example of the cardan type. Thus, each electric motor (4) is not subjected to the shocks and vibrations experienced by the axle (2) associated with it. In addition, the unsprung mass is lower compared to conventional railway vehicles, which is beneficial for comfort and less damaging to the track.
[0077] It will be noted that this suspension is also valid for a non-driven axle (2). In this case, central connecting rods are provided, for example upper (23) and lower (24) connecting rods, which are connected to the axle (2) by a part equivalent to the casing (6) of the reducer (5) of the previous case, but without mechanical transmission members such as the mechanical connection (7).
[0078] Of course, the suspension of the axle (2) by means of the casing (6) of the reducer (5) is only a preferred example. In order for the axle (2) to be able to yaw, it is however essential that it is provided to pivot relative to the chassis (9) of the railway vehicle around a substantially vertical axis.
[0079] The engine (4) is preferably suspended from the chassis (9) of the railway vehicle, although this is not obligatory.
[0080] In the case where there is a suspension device (34) comprising two central connecting rods (23, 24), these connecting rods (23, 24) mainly take up the longitudinal traction and braking forces while the suspension arms (8), the control connecting rods (15) and the control actuators (16) play more of a yaw stabilization role.
[0081] In the case where there is no suspension device (34), it is the control rods (15) which take up all the longitudinal forces, these longitudinal forces being distributed between the articulation point (20) on the chassis and the articulation point (19) on the control actuators (16).
[0082] Although a motorized axle (2) is shown as an example in the figures, it is understood that the assembly according to the invention can be provided for a non-motorized axle (2).
[0083] In the case of a motorized axle (2), an articulated connecting device, for example in the form of upper (23) and lower (24) connecting rods, is provided between the casing (6) and the chassis (9) to take up, among other things, the traction and braking torques.
[0084] The connecting device (1) according to the invention is a so-called trailing arm suspension version. As shown in the figures by way of example, such a connecting device (1) preferably equips each axle (2) of the vehicle, and is more preferably present on both sides of the vehicle, for each of the two axles (2) thereof. Although this seems of little advantage in the case of a light rail vehicle, nothing prevents the use of the connecting device (1) for a single axle (2) and / or on a single side of the vehicle.
[0085] The connecting device (1) comprises a suspension arm (8) provided to carry a lateral end of the axle (2) associated with it. The suspension arm (8) is preferably provided under the chassis (9) and offset laterally on the outer side of the wheel (3) associated with it. It preferably extends substantially horizontally along the longitudinal axis of the railway vehicle, i.e. parallel to the rails of the track.
[0086] It will be noted that the connection between the axle ends (2) and the suspension arms (8) are connections that are free to rotate around the axis of the axle (2) since this axle (2) rotates. These are preferably high-capacity bearings.
[0087] Advantageously, the braking device is positioned between the suspension arms (8) and the wheels (3). The brake discs are connected to the axle (2) while the calipers are fixed to the suspension arms (8), with the brake control members located above the suspension arms (8). Thus the brake discs are well ventilated, protected from ballast projections and the members are accessible for maintenance.
[0088] The chassis (9) of the railway vehicle is connected to the axle (2) in an articulated manner by a first end (10) of the suspension arm (8), while the chassis (9) of the railway vehicle is connected and suspended from the suspension arm (8), at the second end (11) of the suspension arm (8), by means of a suspension device (12).
[0089] All longitudinal and lateral forces and part of the vertical forces are taken up at these joints, while the other part of the vertical forces and the main suspension are taken up by the suspension device (12).
[0090] According to a preferred embodiment of the invention, the axle (2) is connected to the suspension arm (8), between the first end (10) and the second end (11) of said suspension arm (8), preferably at the level of the substantially middle part of said suspension arm (8).
[0091] The suspension device (12) comprises at least one suspension (13) mounted between the chassis (9) of the vehicle and the suspension arm (8) to dampen vertical movements, said suspension (13) being preferably provided at the second end (11) of the suspension arm (8).
[0092] The suspension (13) of the suspension device (12) is preferably a pneumatic spring comprising a diaphragm or a bellows capable of being inflated with compressed air.
[0093] This pneumatic suspension (13) is advantageously provided in particular to manage the height of the chassis (9) of the vehicle relative to the axle (2), for example in order to take into account the load state of the vehicle and / or the heights authorized for the railway vehicle. This advantageously makes it possible to have a constant attitude for the railway vehicle, which facilitates access for people - for example in wheelchairs for example.
[0094] This suspension (13) can also be a hydraulic or electric spring and integrate damping. It can advantageously be controlled in extension to control and correct the attitude of the vehicle.
[0095] The suspension (13) can also be a suspension in the form of a metal spring, for example a coil spring, or an elastomer block, for example made of rubber, but this type of suspension does not allow the vehicle's attitude to be corrected and provides a little less comfort.
[0096] The pneumatic regulation is slow enough to allow dynamic filtration while driving without generating unpleasant rolling movements. The characteristics of this suspension are adapted to filter the vibrations generated by driving and obtain the comfort sought for public transport.
[0097] According to a preferred variant of the invention, the assembly according to the invention comprises a sensor provided between the chassis (9) of the vehicle and the axle (2) equipped with the connecting device (1), this sensor being provided to measure the distance between the chassis (9) and the axle (2) or the elongation of the pneumatic suspension (13) at this axle (2) and to regulate the pressure of the compressed air supplied to the pneumatic suspension (13) as a function of the load state of the vehicle at said axle (2). By adjusting the air pressure supplied to the pneumatic suspension (13), it is thus possible to keep the distance between the chassis (9) and the axle (2) constant. Thus, a constant attitude is obtained for the vehicle regardless of the load.
[0098] According to a preferred variant of the invention, the suspension device (12) also comprises a shock absorber (14) for example of the hydraulic, oleopneumatic or hydropneumatic type. This shock absorber (14) preferably extends in a substantially vertical or inclined manner, but is preferably located in a vertical plane parallel to the general longitudinal direction of the vehicle.
[0099] Preferably, the suspension (13) and the shock absorber (14) are located close and parallel to each other to operate jointly in order to provide a suspension device (12) adapted to the needs of the invention, in particular to provide vertical comfort and adjust the height of the chassis (9) of the vehicle relative to the axle (2).
[0100] The shock absorber (14) has the role of damping the oscillations of the suspension (13).
[0101] The first end (10) of the suspension arm (8) is intended to be mounted articulated to the chassis (9) of the railway vehicle by means of a control rod (15) which is preferably moved in inclination by a control actuator (16).
[0102] This control actuator (16) comprises a body (17) mounted articulated on the chassis (9) of the vehicle, and a movable part (18) connected to a first end of the control rod (15) at a joint (19). The movable part (18) of the control actuator (16) is the movable part for actuating the latter, for example a movable rod in the case where the control actuator (16) is a pneumatic or hydraulic cylinder, the movable tube or the movable screw in the case where the control actuator (16) is a screw and / or nut actuator.
[0103] The control actuator (16) is preferably a cylinder, and more preferably a hydraulic cylinder, which includes a displacement sensor to know its stroke. The hydraulic circuit of the cylinder is preferably designed to put the large chamber of the cylinder on one side in communication with the annular chamber of the opposite cylinder. Thus the flow rate to be provided for controlling the cylinder is the same at the outlet and at the retraction for the same displacement value. The control is thus simplified. A throttle is preferably provided on the hydraulic circuit of the cylinder, so that when the cylinder is passive, it provides hydraulic damping, in particular for the yaw orientation of the axle (2) relative to the chassis (9) of the vehicle. Indeed, in certain track configurations, the control actuator (16) can advantageously become passive and act as a yaw damper.In this case the yaw orientation of the axle (2) is done only by the effect of the bicone of the wheels (3).
[0104] According to a preferred embodiment of the invention, the control actuator (16) extends substantially horizontally along the longitudinal axis of the railway vehicle, while the control rod (15) extends substantially vertically, i.e. substantially perpendicular to the control actuator (16).
[0105] The control rod (15) is preferably in the form of an elongated part, for example a single substantially flat part (see figures 3 and 4) or in the form of two parallel flanks (see figures 2, 5 and 6). Depending on the configuration in which the control rod (15) is in the form of a single elongated part, it is held in a yoke between the flanks of the suspension chair (21) mounted in the lower part of the chassis (9). According to the second configuration, the articulation (22) of the suspension arm (8) can be held in a yoke between the two parallel flanks of the control rod (15).
[0106] According to a first variant shown in Figures 5, 6 and 8, the control rod (15) can be of substantially straight shape.
[0107] According to a second, more advantageous variant shown in Figures 3, 4 and 7, the control rod (15) may be of a slightly curved shape like a boomerang. This curved shape makes it possible to connect the control rod (15) to the control actuator (16) and to the suspension arm (8) at fixing points located substantially along the same substantially vertical axis, and to connect it to the chassis (9) of the vehicle at a point offset longitudinally away from the axle. According to this configuration, the two fixing points of the control rod (15) are not aligned with the articulation (22) of the suspension arm (8), which avoids the creation of an unstable operating point, since little effort is required to move away from it.
[0108] The curved shape for the control rod (15) simplifies the installation of the control actuator (16) in the embodiment shown as an example in the figures. In this embodiment, it will also be noted that the control actuator (16) is positioned in a high position relative to the control rod (15), it could just as easily be positioned elsewhere, for example at the bottom and on the other side of the control rod (15). The installation shown as an example in the figures was chosen in order to allow the installation of an anti-roll bar (25) and to place the control actuator (16) away from ballast projections.
[0109] It will be noted that the location of the articulation points of the control rod (15) is justified by the desired effect of rolling the chassis (9) in coincidence with the yaw of the axle (2) and by the fact of positioning the axis of the control actuator (16) as tangent as possible to the radius described by the articulation point (19) when it rotates around the articulation point, to have similar forces and strokes in one direction as in the other during the movements of the control rod (15).
[0110] According to a preferred embodiment of the invention, a first end of the control rod (15) is mounted articulated at the free end of the movable part (18) of the control actuator (16), while the second end of the control rod (15) is mounted articulated on the chassis (9) at a joint (20).
[0111] The lower part of the control rod (15) where its second end and its articulation (20) are located preferably makes an angle of approximately 30° to 45° relative to the vertical.
[0112] Thus, the axle (2) is connected to the chassis (9) via the upper (23) and lower (24) connecting rods and via the control connecting rod (15). These different articulation points are advantageously positioned so as to allow a parallelogram movement, which advantageously makes it possible to keep the pivot axis of the axle (2) substantially vertical in yaw relative to the chassis (9).
[0113] It will be noted that, due to the inclination of the lower part of the control rod (15) where its second end and its articulation (20) are located, a horizontal force component is generated by the mass of the vehicle. The upper (23) and lower (24) rods take up this component.
[0114] The articulation (20) at the second end of the control rod (15) is preferably mounted on the chassis (9) of the vehicle by means of a part, called a suspension chair (21), which is fixed to said chassis (9), generally in the lower part thereof, and which provides an anchoring point usually offset downwards for the suspension arm (8) on the chassis (9) of the vehicle.
[0115] According to the preferred embodiment shown in the figures, it will be noted that each axle (2) is provided to pivot in a horizontal plane on the chassis (3) of the vehicle and that the chassis (3) is preferably suspended from said axle (2) in different zones.
[0116] The chassis (3) is first of all suspended in an articulated manner from the suspension arms (8) at the level of the suspension chairs (21). As can be seen in particular in Figures 1 to 4, the chassis (3) is connected to the axle (2) by two upper (23) and lower (24) connecting rods rotatably connected to the axle (2), for example at the level of the middle of said axle (2) and / or at the level of the casing (6) of the reducer (5), these two upper connecting rods (23, 24).
[0117] It will be noted that the axle (2) is pivotally connected to the chassis (3) and that it can be connected to said chassis (3) by a substantially central device such as the two upper (23) and lower (24) connecting rods or by the only connecting devices (1) of the invention when the axle (2) is equipped with a connecting device (1) at each of its two wheels (3).
[0118] Thus, the modification of the position of the articulation of the suspension arm (8) by the control actuator (16) leads to the yaw of the axle (2) around a point located approximately at the level of the attachment of these connecting rods (23, 24) on the chassis (9).
[0119] The first end (10) of the suspension arm (8) is connected in an articulated manner to the chassis (9) of the railway vehicle via the control rod (15). Thus, the first end (10) of the suspension arm (8) is fixed to the control rod (15) by an articulation (22), preferably provided between the articulations (19, 20) provided at the two ends of the control rod (15) and more preferably in the substantially middle part of the control rod (15).
[0120] The articulation (22) of the suspension arm (8) is preferably an elastic articulation, which is provided to allow vertical movements, lateral movements and rolling movements of the chassis (9) of the vehicle relative to the suspension arm (8), and to allow the yaw orientation of the axle (2) in curves.
[0121] The articulation (22) of the suspension arm (8) primarily fulfills a kinematic function using the physical principle of the elasticity of the material and preferably comprises an elastomer part. It is preferably an elastic articulation (22) of the anti-vibration type comprising an external ring (28) and an internal ring (29) with an elastic material (30) between the two. Its purpose is to filter the transmission of vibrations generated by rolling. The elastic material (30) is preferably made of rubber, plastic or other materials meeting stiffness and mechanical strength criteria compatible with the mechanical forces received by the articulation (22) of the suspension arm (8). This elastomer part may be heterogeneous, for example of the rubber type, or composite, for example of the rubber-metal type.The elastic material (30) of the articulation (22) of the suspension arm (8) may have recesses to obtain different stiffnesses in x, y and z. This type of elastic articulation is known to those skilled in the art and an example is shown in figures 9 and 10.
[0122] The stiffness of the articulation (22) of the suspension arm (8) is adapted so as to limit the amplitude of the movements. According to a preferred embodiment of the invention, the articulation (22) of the suspension arm (8) is designed to allow vertical, lateral and rolling movements whose amplitude is less than 10 millimeters, preferably less than 8 millimeters and more preferably less than 5 millimeters.
[0123] Thus, when the control actuator (16) pivots the control rod (15), the first end (10) of the suspension arm (8) is moved longitudinally, which mainly has the effect of pivoting the axle (2) in yaw, and also has the effect of laterally tilting the chassis (9) of the vehicle relative to the axle (2) and therefore to the track.
[0124] By a single translational movement of the movable part (18) of the control actuator (16), the assembly of the invention advantageously makes it possible both to orient the axle (2) in yaw in curves and to give heel to the chassis (9) in curves while providing a damping effect on any vertical, lateral and rolling movements of the chassis (9) relative to the axle (2).
[0125] Orienting the axle (2) towards the center of the curve by means of the control actuator (16) allows in particular that the wheel flanges no longer come into contact with the outer rail, which reduces wear, squealing and damage to the rail attachments.
[0126] Giving the chassis (9) some heel in curves makes it possible in particular to compensate for centrifugal effects for greater passenger comfort.
[0127] It will be noted that the articulation (20) provided at the second end of the control rod (15) can also be a substantially elastic articulation similar to the articulation (22) of the suspension arm (8). This thus improves the filtration of vibrations and also allows the control rod (15) to oscillate slightly laterally to provide lateral suspension, a very important suspension in the railway sector, in particular during contact of the wheel flanges on the track. This lateral suspension is preferably supplemented by a lateral damping device (31), comprising for example two shock absorbers (32, 33), preferably of hydraulic and telescopic types. These two shock absorbers (32, 33) are preferably provided one behind the other, symmetrically with respect to the median longitudinal axis of the vehicle, along the same transverse axis, above and substantially in the center of the axle (2), between the casing (6) of the reducer (6) of the axle (2) and the chassis (9).The two lateral shock absorbers (32, 33) are preferably connected to the chassis (9) and to the axle (2) in the central part thereof to absorb the numerous lateral stresses undergone by the axle (2).
[0128] The control actuator (16) of the connecting device (1) can be controlled by the driver of the railway vehicle.
[0129] According to a preferred embodiment of the invention, the control actuator (16) of the connecting device (1) can also be controlled by an automatic servo device. By means of a device for determining the curvature of the track, for example a GPS, feelers, cameras, or the like, this servo device takes note of the layout of the railway track and measures the curve which appears in front of the vehicle in order to control the control actuator (16) to orient the axle (2) and tilt the vehicle towards the center of the curve.
[0130] Advantageously, the control actuator (16) is fixed to the chassis (9) of the railway vehicle and is connected to the control rod (15) so as to produce a lever arm. Thus the stroke of the movable part (18) of the control actuator (16) is greater than that of the articulation (22) of the suspension arm (8). This configuration facilitates the control of the control actuator (16) because the useful stroke at the articulation (22) is small, of the order of a centimeter, for example between 20 and 40 millimeters.
[0131] Generally speaking, it will be noted that the suspension regulation and the design of the suspension arms (8), its articulations, the suspensions (13) and the shock absorbers (14) give the vehicle good quality roll stability.
[0132] In the event of excessive oscillation movement, this type of swinging also being referred to as swaying, it is possible to add an anti-roll bar (25). The anti-roll bar (25) is preferably mounted articulated on the sides at the level of the suspension chairs (21). It extends on each side towards the axle (2) by a lever (26), for example substantially horizontal, and is connected on each side to a suspension arm (8) by a connecting rod (27), for example substantially vertical.
[0133] Roll stability can be ensured by controlling the suspension device (12), for example by independent right-left attitude control. This control can also make it possible to travel on tracks with significant differences in transverse level between two points on the railway, this type of defect also being referred to as lefts. This is particularly advantageous if the chassis (9) of the vehicle is torsionally rigid. Indeed, it will be noted that for crossing lefts, the chassis (9) must be sufficiently flexible in torsion. If the chassis (9) is too rigid, an anti-roll bar (25) can also be provided on only one of the two axles (2).
[0134] We will now describe the operation of the entire invention as shown in the figures. As a preferred example, we will focus on the case of a light rail vehicle whose two axles (2) are each equipped with two connecting devices (1) according to the invention, at the rate of one connecting device (1) at each wheel (3). In the figures, the axis of movement of the vehicle is indicated by an arrow A. It will be noted, however, that the operation of the connecting device (1) of the invention does not depend on the direction of movement of the vehicle.
[0135] The geometry of the means of each connecting device (1) according to the invention is preferably provided so that in static the lower part of the control rod (15) where its articulation (20) is located preferably makes an angle of approximately 30° to 45° relative to the vertical and so that the articulation point (22) of the control rod (15) to the suspension arm (8) is almost fixed in vertical. Thus, the articulation point (20) of the control rod (15) to the chassis (9) is located downwards and offset, preferably towards the chassis (9), and the articulation point (22) of the control rod (15) to the suspension arm (8) is located above the articulation point (20) and offset towards the axle (2). Thus, moving this articulation point relative to the chassis (9) changes the inclination of the control rod (15).As a result, the articulation point (20) of the control rod (15) to the chassis (9) rises or falls, which causes the chassis (9) to roll.
[0136] This geometry is also designed for stops or low-speed driving on curves that may be raised. In these cases, the vehicle leans to the inside of the track and the axle (2) automatically yaws towards the center of the curve. This avoids the risk of derailment.
[0137] Another very important characteristic is that this geometry and the location of the different articulation points mean that the axle (2) tends to automatically return to a position perpendicular to the vehicle. The chassis (9) being suspended from the control rods (15) and these being inclined, a stable position is clearly defined.
[0138] The axle (2) rotates around its center around a quasi-vertical axis, and the two inclined control rods (15) generate opposing longitudinal forces which generate a straight line restoring torque, which is very advantageous in the event of failure of the connecting device (1) according to the invention.
[0139] It will be noted that if the connecting rod is vertical, there is no horizontal return component, designated F below. The slightest force at the low point (see articulation point (20) in the figures) moves this point which remains in this new position due to the different frictions. In this case, the axle (2) is no longer perpendicular to the chassis (9). On the contrary, if the connecting rod (15) is inclined, a relatively large force F is generated applied to the articulation point (20). As there is a force F on either side of the center of rotation of the axle (2), under the action of gravity, a natural return of the axle (2) to a perpendicular position relative to the vehicle is generated. These forces F are sufficient to overcome the friction. Furthermore, regardless of the relative positions, it is sufficient for the connecting rod to be inclined for this to work.
[0140] We will now describe the operation of the entire invention as shown in the figures. As a preferred example, we will focus on the case of a light rail vehicle whose two axles (2) are each equipped with two connecting devices (1) according to the invention, at the rate of one connecting device (1) at each wheel (3). In the figures, the axis of movement of the vehicle is indicated by an arrow A. It will be noted, however, that the operation of the connecting device (1) of the invention does not depend on the direction of movement of the vehicle.
[0141] When the driver of the railway vehicle and / or a suitable device detects that the railway vehicle is entering a curve, the control actuators (16) located on the inside of the curve are actuated so that their movable part (18) is moved in extension. Generally, it is necessary to anticipate a little, of the order of 2 to 5 m, but this also depends on the speed.
[0142] The output of a movable part (18) pivots the control rod (15) associated with it at the articulation (20) provided at its second end. The control rod (15) being connected to a suspension arm (8) at the articulation (22), the pivoting of the control rod (15) exerts forces on the suspension arm (8) associated with it, these forces tending both to move the suspension arm (8) longitudinally towards the center of the chassis (9) (in the preferred case and illustrated by way of example where the control rod (15) is placed on the side of the center of the chassis (9), because it is possible to do the opposite), and the articulation point (20) located on the inner side of the curve is moved downwards.
[0143] In the preferred case where there is a control actuator (16) on both sides of the axle (2), the opposite happens at the second control actuator (16) located on the outer side of the curve: the movable part (18) is retracted, the arm suspension (8) is moved away from the center of the chassis (9) and the articulation point (20) located on the outer side of the curve is moved upwards.
[0144] The longitudinal forces exerted on the suspension arms (8) located on the inner and outer sides of the curve cause each of the axles (2) to pivot, causing them to yaw and allowing them to follow the curve, each axle (2) then being pivoted in the manner of a steering axle.
[0145] The vertical forces exerted on the suspension arms (8) located on the inner side of the curve do not allow the suspension arms (8) to be lifted but are transmitted to the chassis (9). Indeed, the suspension arms (8) are integral with the axles (2) which carry the wheels (3), and these - due to the weight of the vehicle - cannot be lifted from the rails. The axles (2) therefore cannot move vertically relative to the rails. Thus, the vertical forces exerted on the suspension arms (8) result in the chassis (9) moving closer to or further away from the suspension arm (8). Consequently, the vertical forces exerted upwards on the suspension arms (8) bring the chassis (9) closer to said suspension arms (8), which laterally tilts said chassis (9) towards the inner side of the curve, thus giving the chassis (9) a heel in the curve and compensating for the centrifugal effects.
[0146] When the chassis (9) is brought closer to the suspension arms (8) located on one side of the vehicle, it is also moved away from the suspension arms (8) located on the other side of the vehicle.
[0147] In the preferred case where there is a control actuator (16) on both sides of the axle (2), the two control actuators (16) are preferably servo-controlled in opposition. In the event of a servo-control failure or in the event of a large curve or even a straight line, these control actuators (16) become passive and become simple yaw dampers, an important function for the stability of the vehicle.
[0148] Thus, by a small amplitude displacement of the movable part (18) of a single control actuator (16), preferably on both sides of each axle (2), the axles (2) of a railway vehicle can be oriented in yaw and, preferably, the chassis (9) of said vehicle can also be inclined laterally in roll, so that the railway vehicle negotiates the curve better, with increased comfort, and limiting the wear of the wheels (3) and the rails.
[0149] It will be noted that if the two control actuators (16) are correctly controlled, it is possible to do without the central connecting rods (23, 24) which hold the axle (2) in rotation.
[0150] In the case where the axles (2) of the light rail vehicle comprise only one connecting device (1) according to the invention, provided at the level of only one of the two wheels (3), the operating principle is substantially the same. Indeed, if the connecting device (1) is located on the inside of the curve, its operation is identical to that described previously. If the connecting device (1) is located on the outer side of the curve, the movable part (18) of the control actuator (16) is retracted, which pivots the control rod (15) so that the latter exerts forces on the suspension arm (8) associated with it. These forces tend both to move the suspension arm (8) longitudinally away from the center of the chassis (9) and to move the articulation point (20) located on the outer side of the curve vertically upwards. As before, these forces then result respectively in a yaw orientation of the axle to follow the curve and a lateral inclination of the chassis (9) towards the inner side of the curve, and vice versa if the connecting device (1) is located on the outer side of the curve.
[0151] Indeed, several embodiments are possible for the assembly according to the invention.
[0152] According to a preferred embodiment, for the same axle (2) the assembly comprises two control actuators (16), namely a control actuator (16) provided at each of the wheels (3) of said axle (2). According to this embodiment, the pivoting of the axle (2) is carried out by the two control actuators (16), which are preferably hydraulic, but it is also materialized by central connecting rods (23, 24) which retain the axle (2) in rotation or by a similar device.
[0153] According to a first variant, for the same axle (2) the assembly comprises a control actuator (16) at each of the two wheels (3). These two control actuators (16) operate in opposition, that is to say that when the movable part (18) of one of the control actuators (16) retracts, the movable part (18) of the other control actuator (16) moves in extension, and vice versa. According to this embodiment, the pivoting of the axle (2) is carried out by the two control actuators (16) without any articulation point (materialized for example by connecting rods (23, 24)) connecting the middle part of the axle (2) to the chassis (9) being necessary, and can therefore be optional.
[0154] According to a second variant, for the same axle (2) the assembly comprises a control actuator (16) at each of the two wheels (3). These two control actuators (16) do not operate in opposition, but individually and autonomously, which advantageously provides redundancy and / or dampens the yaw movements of the axle. According to this embodiment, an articulation point connects the middle part of the axle (2) to the chassis (9), for example by means of an articulation device such as the connecting rods (23, 24) or another similar device.
[0155] According to a third variant, for the same axle (2) the assembly comprises a single control actuator (16) which is at the level of one of the two wheels (3). According to this embodiment, an articulation point connects the middle part of the axle (2) to the chassis (9), for example by means of an articulation device such as the connecting rods (23, 24) or another similar device.
[0156] It is obvious that the present description is not limited to the examples explicitly described, but also includes other embodiments and / or implementations. Thus, a described technical characteristic can be replaced by an equivalent technical characteristic without departing from the scope of the present invention as defined by the appended claims and a described step of implementing the method can be replaced by an equivalent step without departing from the scope of the invention as defined by the claims.
[0157] Thus, although the assembly according to the invention has been described for a railway vehicle not comprising a bogie, it is obvious to those skilled in the art that the connecting device described is also applicable to a bogie. The axle(s) of the bogie are then connected to the chassis of the bogie by this device.
[0158] Similarly, although the assembly according to the invention was designed for a light rail vehicle with two axles, these axles being driven or not, it is obvious to those skilled in the art to adapt this assembly to other vehicles.
Claims
Claims
1. Assembly comprising an axle (2) equipped with two wheels (3) and at least one connecting device (1) provided for connecting said axle (2) to the chassis (9) of a railway vehicle, characterized in that the axle (2) is capable of being pivoted relative to said chassis (9) around a substantially vertical axis and in that the connecting device (1) comprises the following means: • a control actuator (16) comprising a body (17) and a movable part (18), the body (17) of said control actuator (16) being provided to be connected to the chassis (9) of the vehicle; • a control rod (15) a first end of which is mounted by an articulation (19) at a free end of the movable part (18) of the control actuator (16), while its second end is mounted by another articulation (20) on the chassis (9) of the vehicle;• a suspension arm (8) carrying a lateral end of the axle (2), a first end (10) of said suspension arm (8) being mounted articulated to the control rod (15) by an articulation (22); and • a suspension device (12) comprising at least one suspension (13) provided between the chassis (9) of the vehicle and the suspension arm (8) to suspend and dampen vertical movements;these means being arranged so that when the control rod (15) is pivoted by the control actuator (16), the axle (2) pivots relative to the chassis (9) around a vertical axis and in that the axle (2) is connected to the suspension arm (8), between the first end (10) and the second end (11) of said suspension arm (8), preferably at the level of the substantially middle part of said suspension arm (8) so that the point of application of the forces exerted by the control rod (15) on the suspension arm (8) at the level of the articulation (22) is distant from the lateral end of the axle (2) carried by said suspension arm (8).;
2. Assembly according to claim 1, characterized in that the part of the control rod (15) comprising the articulation (20) provided in its second end is inclined longitudinally towards the center of the chassis (9) at an angle between between 10° and 65°, preferably between 20° and 55°, and more preferably between 30° and 45° relative to the vertical.
3. An assembly according to claim 1 or claim 2, characterized in that the control actuator (16) is a hydraulic cylinder.
4. Assembly according to any one of the preceding claims, characterized in that the articulation (22) of the suspension arm (8) is an elastic articulation provided to allow, with a determined stiffness, vertical movements, lateral movements and rolling movements of the chassis (9) of the vehicle relative to the suspension arm (8), and to allow the yaw orientation of the axle (2) in curves, the stiffness of the articulation (22) in x, y and z being between 2 x 105 N / m and 2 x 107 N / m, preferably between 7 x 105 N / m and 7 x 106 N / m and more preferably between 1 x 106 N / m and 5 x 106 N / m.
5. Assembly according to any one of the preceding claims, characterized in that the suspension arm (8) extends substantially horizontally along the longitudinal axis of the railway vehicle so that, when the connecting rod (15) is pivoted by the control actuator (16) and exerts a force on the suspension arm (8) at the articulation (22), the kinematics of this connecting rod generates a vertical force component and laterally tilts the chassis (9) of the railway vehicle relative to the track.
6. Assembly according to any one of the preceding claims, characterized in that the suspension arm (8) is provided under the chassis (9) and on the outside of the wheel (3) associated with it so as to improve the roll resistance of the railway vehicle.
7. Assembly according to any one of the preceding claims, characterized in that the control actuator (16) extends substantially horizontally along the longitudinal axis of the railway vehicle and in that the control rod (15) extends substantially vertically so that, when the movable part (18) of said control actuator (16) is moved, the control rod (15) is pivoted in a vertical plane by the control actuator (16) and orients the axle (2) in yaw.
8. Assembly according to any one of the preceding claims, characterized in that the articulation (22) of the suspension arm (8) is provided between the two joints (19, 20) of the control rod (15).
9. Assembly according to any one of the preceding claims, characterized in that the suspension (13) of the suspension device (12) is a pneumatic spring, preferably comprising a diaphragm or a bellows capable of being inflated with compressed air.
10. Assembly according to the preceding claim, characterized in that it comprises a sensor between the axle (2) and the chassis (9) of the vehicle, this sensor being provided to measure the load state of the vehicle and regulate the pressure of the compressed air supplied to the suspension (13) as a function of said load state.
11. Assembly according to any one of the preceding claims, characterized in that the suspension device (12) comprises a substantially vertical or inclined shock absorber (14) of the hydraulic, oleopneumatic or hydropneumatic type.
12. Assembly according to any one of the preceding claims, characterized in that the articulation (20) of the control rod (15) on the chassis (9) is an elastic articulation provided to allow, with a determined stiffness, at least lateral movements of the control rod (15) relative to the chassis (9).
13. Assembly according to any one of the preceding claims, characterized in that it comprises a lateral damping device (31) provided to connect the axle (2) to the chassis (9) so as to dampen the lateral stresses generated by the axle (2) and transmitted to the chassis (9).
14. Assembly according to the preceding claim, characterized in that the lateral damping device (31) comprises two dampers (32, 33) provided one behind the other and symmetrically with respect to the median longitudinal axis of the vehicle.