Patent Application
20240425092
The invention relates to a rail vehicle having at least a first carriage and a second carriage which are coupled to one another via a carriage articulation device, where the carriage articulation device has a variable resistance to twisting of the at least first carriage relative to the second carriage.
High demands are often placed on rail vehicles in terms of driving characteristics, driving safety and driving comfort. Connections between individual carriages of a rail vehicle influence the driving characteristics of the rail vehicle. For example, multiple-articulation low-floor trams having long head vehicle modules and having chassis arranged in rear regions of the head vehicle modules, as a result of wide doors in front regions of the head modules, have carriage centers of gravity in the head vehicle modules, which carriage centers of gravity are arranged in front of the chassis centers of gravity in the direction of travel.
As a result of such carriage centers of gravity, multiple-articulation low-floor trams often have cornering characteristics in the case of which the head vehicle modules, as a result of centrifugal forces when entering a corner, are firstly urged in the direction of the outside of the curve and are forced suddenly into the curve progression when the chassis begin to follow curve progressions.
DE 10 2007 004 522 A1, for example, discloses a rail vehicle formed as an articulated train. Here, articulation apparatuses and damping apparatuses are arranged between individual carriages of the rail vehicle. The damping apparatuses cause speed-dependent damping of pivoting movements of individual carriages relative to one another, where a resistance force against the pivoting movements increases linearly with increasing pivoting speed and the articulation apparatuses are stiffened. As a result of this, its derailment stability should be improved, particularly in the case of collisions of the rail vehicle.
The conventional approach has the disadvantage that this relates to extraordinary scenarios (collisions), where a rigidity of carriage articulations that increases with increasing speed is, for example, not suitable to increase the driving safety and the driving comfort of the rail vehicle when entering curves.
In view of the foregoing, it is therefore an object of the invention to provide an improved a rail vehicle, in which the carriage articulation device, particularly when entering into track curves enables particularly high driving safety and particularly high driving comfort.
This and other objects and advantages are achieved in accordance with the invention by a rail vehicle in which a first resistance torque gradient of the carriage articulation device is greater in magnitude cases of a first angular position of at one least first carriage relative to a second carriage in one direction of rotation than a second resistance torque gradient of the carriage articulation device in cases of a second angular position of the at least first carriage relative to the second carriage in the same direction of rotation, where the first angular position is associated with a lesser twisting of the at least one first carriage relative to the second carriage than the second angular position. This measure provides a variable rotational resistance of the carriage articulation device via which, on one hand, transverse forces cannot only be transmitted from the first carriage to a chassis of the at least one first carriage, but rather, in order to stabilize the rail vehicle to a certain extent, also to the second carriage and which, on the other hand, reduces in terms of its increase when entering a curve with an increasing relative angular position between the at least one first carriage and the second carriage. As a result of this, this rotational resistance does not hinder steering of the first carriage into the curve and does not lead to excessive guiding forces between wheel sets of the chassis and rails of a track.
Improvements in terms of driving dynamics of rail vehicles entering track curves are facilitated, for example, if a first resistance torque of the carriage articulation device in the case of the first angular position has a greater magnitude than a second resistance torque of the carriage articulation device in the case of a third angular position of the at least one first carriage relative to the second carriage in the same direction of rotation, where the first angular position is associated with a lesser twisting of the at least one first carriage relative to the second carriage than the third angular position.
It may also be helpful if the carriage articulation device has a maximum third resistance torque in terms of magnitude in the case of a fourth angular position of the at least one first carriage relative to the second carriage between the first angular position and the third angular position in the same direction of rotation.
A profile of a resistance torque above an angular position can be mapped, for example, by a higher-order non-linear function. As a result of the maximum third resistance torque between the first angular position and the third angular position, it possible to achieve a situation in which the carriage articulation device initially has a stiffening or stabilizing effect in the case of small angular positions and yields, in the case of larger angular positions, such as those that occur, for example, when the at least one first carriage is already entering a curve, while the second carriage is still driving on a straight section. As a result of this, an improvement in terms of driving dynamics of the rail vehicle is achieved when entering into curves.
A particularly robust and maintenance-friendly solution is obtained if the carriage articulation device has a pivot point, where a first spring is connected to the at least one first carriage and the second carriage, and where a first normal distance between a first spring longitudinal axis of the first spring and the pivot point is variable, and if a second spring is connected to the at least one first carriage and the second carriage, where a second normal distance between a second spring longitudinal axis of the second spring and the pivot point is variable.
As a result of this measure, resistance torques of the carriage articulation device are formed and adjusted by spring forces of the first and second springs and by the first and second normal distances that act as lever arms. As a result of a variability of the first and second normal distances, resistance torques formed during twisting of the first carriage relative to the second carriage are reduced in magnitude in terms of their gradients with an increasing relative angular position between the first carriage and the second carriage. If the gradients change their plus/minus sign, for example, during the twisting, the resistance torques themselves can also be reduced in terms of magnitude.
It is furthermore helpful if the first and second springs are pretensioned. As a result of this, the carriage articulation device has a base resistance in the translational direction (e. g., in the direction of a vehicle longitudinal axis).
A damping of relative movements between the first carriage and the second carriage is furthermore brought about if the first spring is combined with a first damper to form a first spring/damper unit and the second spring is combined with a second damper to form a second spring/damper unit.
It is furthermore advantageous if the first normal distance in the first angular position is greater than in the second angular position. As a result of its reducing tendency between the first angular position and the second angular position, the first normal distance contributes to a reduction in terms of magnitude of resistance torque gradients or the resistance torques themselves.
An alternative solution for forming and adjusting suitable resistance torques of the carriage articulation device based on a kinematic coupling is obtained if the carriage articulation device has a curved molding that is bent multiple times in opposite directions, a first guide arm, a first roller that is connected rotatably to the first guide arm, a second guide arm and a second roller that is connected rotatably to the second guide arm, where the first and second guide arms are coupled to the at least one first carriage in an articulated manner, where the curved molding is coupled to the second carriage, and where the first and second rollers, on one hand, and the curved molding, on the other hand, are coupled to one another via rolling contacts. As a result of this measure, profiles of the resistance torques can be predefined by geometrical shaping of the curved molding and are not bound to spring parameters that are only adjustable to a restricted extent (e.g., spring rigidity, or pretensioning).
It is expedient in relation to an adjustment of the profiles of the resistance torques if the curved molding has an undulating first mold contour that contacts the first roller and an undulating second mold contour that contacts the second roller.
In this context, it is particularly helpful if the first roller contacts a first wave trough of the first mold contour and the second roller contacts a second wave trough of the second mold contour if the at least first carriage has a neutral angular position of 0° relative to the second carriage.
The first roller and the second roller are surrounded by the first wave trough and the second wave trough. Resistances must be overcome in order to guide the first roller and the second roller out of the first wave trough and the second wave trough. If the first roller and the second roller, however, reach wave peaks of the first mold contour and the second mold contour with an increasing relative angular position between the first carriage and the second carriage, for example, a further increase in the angular position can bring about a reducing resistance torque of the carriage articulation device.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
The invention is explained in greater detail below on the basis of exemplary embodiments, in which:
The rail vehicle is formed as a low floor tram. The first carriage 1 has a first idler chassis 3, and the second carriage 2 has a second idler chassis 4. The rail vehicle comprises further chassis and further carriages which are, however, not represented in
The first carriage 1 and the second carriage 2 are coupled to one another via a carriage articulation device 5, where the carriage articulation device 5 has a variable resistance against twisting of the first carriage 1 relative to the second carriage 2. This twisting occurs substantially in relation to a parallel to a vehicle vertical axis 42 of the rail vehicle that appears in a projecting manner in
The carriage articulation device 5 comprises a carriage articulation 6, in the center of which a pivot point 7 of the carriage articulation device 5 is arranged, and comprises a first spring 8 and a second spring 9. The first spring 8 and the second spring 9 are connected to the first carriage 1 and the second carriage 2 in an articulated or rotatable manner and are formed as pretensioned, metallic screw/compression springs.
A first spring longitudinal axis 10 of the first spring 8 and a second spring longitudinal axis 11 of the first spring 9 are, in a relative neutral angular position 12 of 0° between the first carriage 1 and the second carriage 2, as is represented in
If the first carriage 1 travels into a track curve, then an angular position between the first carriage 1 and the second carriage 2 is increased firstly from the neutral angular position 12 because the second carriage 2 is still traveling along a straight section of track. When the first carriage 1 is entering the track curve, a first angular position 16 is gradually reached between the first carriage 1 and the second carriage 2 and later, via a second angular position 17 shown in
A first spring force of the first spring 8 and a second spring force of the second spring 9 change during twisting between the neutral angular position 12, the first angular position 16, the second angular position 17 and the third angular position 18, because the first spring 8 and the second spring 9 are compressed or expanded during twisting as a result of their connections to the first carriage 1 and to the second carriage 2.
The first normal distance 14 and the second normal distance 15 change during twisting because the first spring longitudinal axis 10 and the second spring longitudinal axis 11 change their orientation during twisting.
A resistance torque of the carriage articulation device 5 is changed via the first spring 8 and the first normal distance 14 and via the second spring 9 and the second normal distance 15.
During the described twisting, the first spring 8 is compressed and the first spring force is increased, as a result of which the resistance torque between the neutral angular position 12 and the first angular position 16 is increased. At the same time, the first normal distance 14, however, is reduced during twisting. In the case of twisting beyond the first angular position 16, the reducing first normal distance 14 influences the resistance torque to a greater extent than the first spring force which reaches a spring force maximum during twisting.
As a result of this, the resistance torque reduces in terms of magnitude once a resistance torque maximum is reached, which resistance torque maximum is arranged between the first angular position 16 and the third angular position 18.
The second spring force initially decreases during the stated twisting and rotates from a relaxed spring position about 180°, and therefore transforms from a compressive force into a tensile force. The second normal distance 15 does indeed increase during the stated twisting, but this, as a result of the second spring force that initially reduces during twisting and is later rotated about 180°, only insignificantly influences the resistance torque or not in an undesirable manner. As a result, the resistance torque does not change in its initially increasing and, once the resistance torque maximum is reached, decreasing tendency.
The graphical plot has an x-axis 20 on which the angular position is plotted as well as a y-axis 21 on which the resistance torque is plotted. The profile of the resistance torque is non-linear.
In a neutral angular position 12 of 0°, the resistance torque is not equal to zero because a carriage articulation 6 of the carriage articulation device 5 has a base rotational resistance.
In the case of a first angular position 16 between the first carriage 1 and the second carriage 2 in a direction of rotation that is greater than the neutral angular position 12, the carriage articulation device 5 has a first resistance torque 22 against a twisting of the first carriage 1 relative to the second carriage 2 that is greater than the resistance torque in the neutral angular position 12. In the first angular position 16, the carriage articulation device 5 furthermore has a first resistance torque gradient 25.
In the case of a second angular position 17 between the first carriage 1 and the second carriage 2 in the same direction of rotation, the carriage articulation device 5 has a second resistance torque gradient 26. The first resistance torque gradient 25 is greater in terms of magnitude than the second resistance torque gradient 26. An increase in the resistance torque therefore reduces, where the profile of the resistance torque becomes flatter.
In the case of a third angular position 18 between the first carriage 1 and the second carriage 2 in the same direction of rotation, the carriage articulation device 5 has a second resistance torque 23 against the twisting of the first carriage 1 relative to the second carriage 2.
In the third angular position 18, the first carriage 1 is twisted to a greater extent relative to the second carriage 2 than in the first angular position 16. The first resistance torque 22 is greater in terms of magnitude than the second resistance torque 23.
The carriage articulation device 5 furthermore has, in the case of a fourth angular position 19 between the first angular position 16 and the third angular position 18, a maximum third torque resistance 24 in terms of magnitude. The resistance torque therefore increases in terms of magnitude from the resistance torque in the neutral angular position 12 via the first resistance torque 22 in the first angular position 16 up to the maximum third resistance torque 24 and then reduces in terms of magnitude in the case of a further increase in the angular position between the first carriage 1 and the second carriage 2 in the same direction of rotation via the second resistance torque 23 in the third angular position 18.
The profile of the resistance torque between the first resistance torque 22 and the second resistance torque 23 is influenced because a first normal distance 14 described by way of example in conjunction with
In accordance with the invention, it is also conceivable to allow the resistance torque to increase in terms of magnitude only to such an extent that the second resistance torque gradient 26 is reached because a reduction in the resistance torque gradient already delivers improvements in terms of driving dynamics when the rail vehicle enters track curves.
This exemplary second embodiment is structurally and functionally similar to that exemplary first embodiment of a rail vehicle in accordance with the invention that is represented in
In contrast to
A first spring 8 and a first damper 27 are combined to form the first spring/damper unit, and a second spring 9 and a second damper 28 are combined to form the second spring/damper unit. The first spring 8 and the second spring 9 are formed as pressure-pretensioned helical springs, where the first spring 8 sheathes the first damper 27 and the second spring 9 sheathes the second damper 28. The first damper 27 and the second damper 28 are formed as hydraulic telescopic dampers.
A first spring longitudinal axis 10 of the first spring/damper unit and a second spring longitudinal axis 11 of the second spring/damper unit are oriented in that neutral angular position 12 shown in
The first carriage 1 has a first idler chassis 3, the second carriage 2 has a second idler chassis 4. The rail vehicle comprises further carriages and further idler chassis, which are, however, not shown in
The carriage articulation device 5 furthermore has a curved molding 29 that is bent multiple times in opposite directions, a first guide arm 30, a first roller 32 that is connected rotatably to the first guide arm 30, a second guide arm 31 and a second roller 33 that is connected rotatably to the second guide arm 31. The first guide arm 30 and the second guide arm 31 are coupled to the first carriage 1 in an articulated manner. The curved molding 29 is connected to the second carriage 2, immovably relative to the second carriage 2.
The first roller 32 and the second roller 33 are coupled to the curved molding 29 via rolling contacts, i.e., can roll on the curved molding 29. The curved molding 29 has an undulating first mold contour 34 which contacts the first roller 32 and an undulating second mold contour 35 that contacts the second roller 33.
In a neutral angular position 12 of 0° between the first carriage 1 and the second carriage 2, as shown in
In the described neutral angular position 12, the first roller 32 contacts a first wave trough 36 of the first mold contour 34 and the second roller 33 contacts a second wave trough 37 of the second mold contour 35.
If the first carriage 1 deflects during a twisting relative to the second carriage 2 from the neutral angular position 12 in the direction of rotation of a first angular position 16, then the first roller 32 moves out of the first wave trough 36 to a first wave peak 38 of the first mold contour 34 and the second roller 33 moves from the second wave trough 37 to a second wave peak 39 of the second mold contour 35.
Contact forces between the first roller 32 and the first mold contour 34 and between the second roller 33 and the second mold contour 35 increase in magnitude.
A resistance torque of the carriage articulation device 5, formed from the contact forces and from variable normal distances between the contact forces and a pivot point 7 of the carriage articulation device 5 increases as a result, where a resistance torque gradient between the first angular position 16 and a second angular position 17 as a result of a decreasing pitch between wave troughs and wave peaks of the curved molding 29 decreases in terms of magnitude.
If the first carriage 1 further twists relative to the second carriage 2 in the same direction of rotation, i.e. in the direction of a third angular position 18, then the first roller 32 rolls from the first wave peak 38 and the second roller 33 rolls from the second wave peak 39. As a result of this, the contact forces and the resistance torque are reduced.
A profile of the resistance torque as a function of an angular position, proceeding from the neutral angular position 12 in the direction of the first angular position 16, of the second angular position 17 and the third angular position 18, is similar to that profile which is represented in
A pressure-pretensioned first contact pressure spring 40 is arranged between the first carriage 1 and the first guide arm 30, and a pressure-pretensioned second contact pressure spring 41 is arranged between the first carriage 1 and the second guide arm 31. The first contact pressure spring 40 pushes the first roller 32 against the first mold contour 34, the second contact pressure spring 41 the second roller 33 against the second mold contour 35. In accordance with the invention, it is also conceivable that the first roller 32 and the second roller 33 are connected via a brace and are thus pushed against the first mold contour 34 or the second mold contour 35.
In accordance with the invention, it is furthermore conceivable that the first guide arm 30 and the second guide arm 31 themselves have contact pressure structures, for example, torsion springs in articulations of the first guide arm 30 and of the second guide arm 31.
Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements that perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| A 50780/2021 | Sep 2021 | AT | national |
This is a U.S. national stage of application No. PCT/EP2022/076731 filed 26 Sep. 2022. Priority is claimed on Austrian Application No. A50780/2021 filed 30 Sep. 2021,the content of which is incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/076731 | 9/26/2022 | WO |
