Patent Publication Number: US-8122835-B2

Title: Undercarriage for a rail vehicle

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is the U.S. National Stage of International Application No. PCT/EP2008/053031, filed Mar. 13, 2008, which designated the United States and has been published as International Publication No. WO 2008/113744 and which claims the priority of German Patent Application, Serial No. 10 2007 013 050.5, filed Mar. 19, 2007, pursuant to 35 U.S.C. 119(a)-(d). 
     BACKGROUND OF THE INVENTION 
     The invention relates to an undercarriage for a rail vehicle, which undercarriage has an undercarriage frame having two longitudinal supports and at least one transverse support connected thereto. The undercarriage has at least two wheelsets which are mounted in wheelset bearings and each have a wheelset shaft and two wheels. The wheelset bearings are connected to the undercarriage frame. The undercarriage has at least one drive, accommodated in the undercarriage frame, for driving one wheelset shaft in each case, wherein the at least one drive is suspended in a movable fashion on the at least one transverse support. 
     The undercarriage is preferably a bogie, in particular a motor bogie. The rail vehicle can be, for example, a locomotive, an urban railway vehicle, an underground railway vehicle or a tram. An undercarriage typically accommodates two drives which each drive one wheelset shaft. A drive typically has a traction motor and a transmission connected thereto. Alternatively, just one driven wheelset may be accommodated in the undercarriage. It is also possible for a plurality of driven wheelsets, for example three or four, to be accommodated. In addition to the driven wheelsets, non-driven wheelsets may also be accommodated in the undercarriage. The wheelsets may be fixedly-mounted-wheel wheelsets or individually-mounted-wheel wheelsets. 
     The international publication WO 01/079048 A1 describes such an undercarriage for a rail vehicle. In one embodiment, drives are arranged in a co-axial design in the region of the transverse support. In a further embodiment, traction and compression forces are transmitted to the superstructure of the rail vehicle via a tension/compression rod, in the form of a low traction linkage, connected to the drive. The drive is of a non-co-axial design. In a further embodiment, the drives are connected to one another via rods or bars. In each case, two rods which are arranged parallel one on top of the other connect two drives to one another. In this embodiment, the drives are of a co-axial design. 
     Furthermore, undercarriages with cannon box drives or axial-riding drives are generally known from the prior art. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to specify an undercarriage for a rail vehicle, which undercarriage is of a design which is lighter in weight compared to the prior art. 
     The object of the invention is achieved with an undercarriage having an undercarriage frame including two longitudinal supports and at least one transverse support connected thereto, at least two wheelsets which are mounted in wheelset bearings and each have a wheelset shaft and two wheels, wherein the wheelset bearings are connected to the undercarriage frame, at least one drive, accommodated in the undercarriage frame, for driving one wheelset shaft in each case, wherein the at least one drive is suspended in a movable fashion on the at least one transverse support, wherein the at least one transverse support can be connected in an articulated fashion to a locomotive body or railcar body by means of, in each case, at least one tension/compression element which is connected in an articulated fashion to an upper side and to a lower side of the transverse support. 
     According to the invention, the at least one transverse support is connected in an articulated fashion to a locomotive body or railcar body by means of, in each case, at least one tension/compression element which is connected in an articulated fashion to an upper side and to a lower side of the at least one transverse support. 
     As a result, driving forces and braking forces or traction forces and compression forces in the direction of travel of the undercarriage are advantageously applied from the wheel/rail contact into the drive and further via the tension/compression rods directly into the transverse support and to the locomotive body or railcar body while largely avoiding the bogie frame. 
     The tension/compression rods can be connected to the locomotive body or railcar body on both sides thereof, that is to say there are four tension/compression rods which connect the at least one transverse support to the locomotive body or railcar body. Alternatively, there may also be just two tension/compression rods which connect the at least one transverse support to the locomotive body or railcar body. 
     The braking forces may not only be caused by the drives but also by a mechanical braking device such as, for example, a disk brake or an electromagnetic rail brake or else by an eddy current brake which operates in a contactless fashion. 
     The design of the undercarriage is also simplified. In addition, the overall mass of the undercarriage is advantageously reduced. As a result of this, the running behavior of the undercarriage is improved. 
     In particular, the undercarriage has (just) one transverse support on which two drives are suspended. Alternatively, the undercarriage can also have two or even three transverse supports. One or two drives, which each drive a wheelset, can be suspended on each transverse support. If there are two transverse supports, each transverse support can be connected to the adjacent locomotive body or railcar body by means of two tension/compression rods. It is also possible for the upper tension/compression rod to be connected to both upper sides of the transverse support and for the lower tension/compression rod to be connected to both lower sides of the transverse support. In this case, the tension/compression rods can be connected to the locomotive body or railcar body on just one side or on both sides. Any desired combinations are conceivable for the abovementioned exemplary configuration variants of the undercarriage. 
     According to one embodiment, the tension/compression elements each have a first end. A bearing block is respectively arranged on the upper side and on the lower side of the transverse support. The first ends of the tension/compression elements form in each case one joint with the respectively bearing block. The bearing block can, for example, be welded, riveted or screwed to the transverse support. Said bearing block can also be an integral component of the transverse support itself. 
     In particular, according to a further embodiment, the joints are arranged in a cross-sectional plane through the center of the undercarriage. 
     The “cross-sectional plane” extends, in particular through the (structural) center of the vehicle. At the same time, said “cross-sectional plane” is perpendicular to the plane of the rails, that is to say orthogonal to a plane running through the rotational axes of the wheelset shafts if the wheels of the undercarriage have the same wheel diameter. In addition, the cross-sectional plane extends in parallel and in the center with respect to the rotational axes of the wheelset shafts. Such an arrangement of the abovementioned components simplifies the design of the undercarriage further. 
     According to another embodiment, the joints are arranged in a longitudinal-sectional plane through the center of the undercarriage. “Longitudinal-sectional plane” denotes a plane extending perpendicularly with respect to the plane of the rails. Said “longitudinal-sectional plane” is therefore at the same time perpendicular to a plane extending through the rotational axes of the wheelset shafts if the wheels of the undercarriage have the same wheel diameter. The intersection line of the cross-sectional plane with the longitudinal-sectional plane is here at the same time a (structural) axis of reflection of the undercarriage. The center of the undercarriage is typically the axis of reflection of the components of the undercarriage. 
     If the joints are arranged both in the cross-sectional plane and in the longitudinal-sectional plane of the undercarriage, the longitudinal forces from the transverse support are advantageously applied as centrally as possible to the locomotive body or railcar body via the tension/compression rods. This simplifies the design of the undercarriage further. 
     According to one particularly advantageous embodiment, the joints are spherical bearings or ball bearings. This permits torque-free application of the longitudinal forces, that is to say the traction forces and compression forces, from the transverse support to the locomotive body or railcar body. 
     The transverse support preferably has a longitudinal-symmetry axis which extends in a cross-sectional plane through the center of the undercarriage. The transverse support is preferably arranged in the geometric center of the undercarriage. Said longitudinal-symmetry axis extends perpendicularly with respect to the plane of the rails and forms at the same time the intersection line of the (structural) longitudinal-sectional plane with the (structural) cross-sectional plane of the undercarriage. When the transverse support is arranged in such a way, the term central transverse support is also used. 
     The at least one transverse support preferably has a transverse-symmetry axis which extends in a longitudinal-sectional plane through the center of the undercarriage. This simplifies the design of the undercarriage further. 
     In particular, the longitudinal-symmetry axis and the transverse-symmetry axis of the at least one transverse support extend in a plane which extends through the rotational axes of the wheelset shafts. 
     According to a further advantageous embodiment, the tension/compression elements have a longitudinal axis. The longitudinal axes extend parallel to one another. In addition to the application of longitudinal forces, this arrangement also advantageously permits torques to be applied from the drives to the locomotive body or railcar body. 
     According to a further embodiment, the tension/compression elements are arranged in mirror-inverted fashion with respect to a plane extending through the rotational axes of the wheelset shafts. In this case, the resultant force of two tension/compression elements when the longitudinal forces are applied to the locomotive body or railcar body extends precisely in this plane and preferably along the intersection line between the longitudinal-sectional plane and the plane extending through the rotational axes of the wheelset shafts. This permits virtually torque-free application of the torques originating from the drives to the locomotive bodies or railcar bodies. The torques which are applied to the transverse support are immediately applied further to the locomotive body or railcar body via the tension/compression elements. Torque-associated loading of the undercarriage frame therefore occurs only to a small degree. 
     According to one particular embodiment, the wheelset bearings in the undercarriage frame are each connected to at least one transverse support by means of a wheelset connecting rod. As a result, in addition to application of the longitudinal forces from the wheel contact points to the transverse support via the wheelset bearing and the wheelset connecting rods, transverse forces can also advantageously be applied to the transverse support. The applied forces are applied to the locomotive body or railcar body via the tension/compression elements. 
     The at least one transverse support is preferably connected laterally to the wheelset connecting rods. The wheelset connecting rods can be connected to the transverse support by means of a comparatively rigid connecting element such as, for example, a rubber/metal element. 
     According to one preferred embodiment, the two drives accommodated in the undercarriage frame are cannon box drives with one traction motor and one transmission each. The traction motors are connected to a cannon box tube which is rotatably mounted co-axially with respect to the wheelset shaft. The traction motor has a torque support by means of which the respective traction motor is connected in an articulated fashion to the transverse support. As an alternative to the cannon box drives, the drives accommodated in the undercarriage frame can be axial-riding drives with one traction motor and one transmission each. Alternatively, it is possible for just one cannon box drive to be accommodated in the undercarriage. It is also alternatively possible for three or more cannon box drives to be accommodated. 
     As a result, the driving torques or braking torques of the cannon box drive can advantageously be supported on the transverse support. 
     In this embodiment, the traction motor is seated, as it were, on the wheelset or on the wheelset shaft. Between the wheelset shaft and the cannon box tube, cannon boxes are arranged which, to a certain degree, also permit axial relative movement between the cannon box tube and the wheelset shaft. The word “axial” denotes directions parallel to the rotational axis of the wheelset shaft. The transmission has gear wheels which mesh with one another. The transmission usually has a large wheel and a small wheel, which transmission is driven by the traction motor. The large wheel is connected in a rotationally fixed fashion to the wheelset shaft. 
     Furthermore, the torque supports can be connected in an articulated fashion to the lower side of the transverse support. Alternatively, said torque supports can be connected in an articulated fashion to the transverse support via one pendulum each. The latter embodiment permits a more elastic connection of the drives to the transverse support. Only parts of the drive masses are therefore suspended primarily on the transverse support in the vertical direction. They therefore do not form part of the unsprung part of the wheelset masses. 
     According to a further embodiment, the transverse support has two side regions which each lie opposite a traction motor. In each case one bracket is arranged in the side region of the transverse support. The upper end of the pendulum is accommodated in an articulated fashion in the bracket. The lower end of the pendulum is connected in an articulated fashion to the torque support of the respective traction motor. The suspension of the traction motor and of the drive which oscillate to a certain extent can compensate better compensation movements of the traction motors during travel. 
     According to a further advantageous embodiment, in each case a bearing block or bracket for the articulated connection of the tension/compression elements is arranged on the upper side (OS) and lower side (US) of the transverse support. In addition, in each case a traction force connecting rod is arranged in an articulated fashion between the lower bearing block and the torque supports. 
     By means of the traction force connecting rods, the traction forces and braking forces can be applied more directly to the transverse support via the cannon box drive. In particular, the traction force connecting rods have a longitudinal axis which each extend in a longitudinal-sectional plane through the center of the undercarriage. 
     If, according to a further embodiment, the traction force connecting rods are arranged parallel to a plane extending through the rotational axes of the wheelset shafts, the traction forces and braking forces can be applied to the transverse support in a plane parallel to the tension/compression elements. 
     According to a further embodiment, the traction force connecting rods are arranged between the lower side of the transverse support and the lower tension/compression element. This arrangement permits the traction forces and braking forces which are passed on via the torque supports and which are relatively small in absolute terms to be applied to the transverse support as close as possible to the plane extending through the rotational axes of the wheelset shafts. 
     The wheelset connecting rods are preferably arranged parallel to the traction force connecting rods. As a result of the apportionment of forces it is possible for the wheelset connecting rods to be made less rigid with respect to the connection to the transverse support compared to the solution without traction force connecting rods. This is more favorable in terms of technical running properties when the undercarriage travels through a bend. 
     When the traction force connecting rods are arranged centrally, that is to say the traction force connecting rods are arranged in the plane of the wheelset shafts and the longitudinal-sectional plane of the undercarriage, comparatively small bending torques about the vertical axis of the transverse support result owing to the traction forces and braking forces compared to the application of these forces via the wheelset connecting rods. 
     According to one particularly advantageous embodiment, in each case two cannon boxes are arranged between the wheelset shaft and the cannon box tube. The cannon boxes form in each case an integrated structural unit with the wheelset bearings. This reduces the expenditure on components for such an undercarriage. 
     As an alternative to the cannon box drives, the two drives accommodated in the undercarriage frame can be axial-riding drives with one traction motor and one transmission each. Alternatively, there may be one, three or more axial-riding drives in the undercarriage. 
     In this embodiment, the traction motor is connected, in particular, in a transversely elastic fashion to the transverse support. The traction motors can be attached to the transverse support by means of a rubber element, for example. As a result of the connection to the transverse support, the traction motor is part of what are referred to as the sprung masses. The transmission has gear wheels which mesh with one another. The transmission usually has a large wheel and a small wheel or alternatively a large wheel, an intermediate wheel and a small wheel. The large wheel is connected in a rotationally fixed fashion to the wheelset shaft. In order to transmit torque, the small wheel and a motor shaft of the traction motor may be connected via a toothed coupling. The toothed coupling permits both axial and radial relative movements of the motor shaft with respect to a transmission input shaft of the small wheel. The word “radial” denotes directions toward the rotational axis of the motor shaft and away from said rotational axis. The toothed coupling decouples the sprung mass of the traction motor from the unsprung mass of the axial-riding transmission. 
     In one particular embodiment, the one transmission has an even number of transmission stages, and the other transmission has an uneven number of transmission stages with the same transmission ratio. The first transmission is preferably a single-stage transmission, and the second transmission a two-stage transmission. Alternatively, the first transmission can, for example, be designed with two stages and the second transmission with three stages. 
     As a result, the reaction torques of the traction motors which act on the transverse support are compensated. 
     The transmissions of the axial-riding drives are preferably connected to a cannon box tube which is rotatably mounted co-axially with respect to the wheelset shaft. This permits a small degree of axial relative movement of the cannon box tube with respect to the wheelset shaft. 
     According to a further embodiment, the tension/compression elements and/or the traction force connecting rods are rigid tension/compression rods. 
     They can have a hinge joint or ball-socket joint at the respective end. They can also have eyelets which correspond to respectively corresponding bearing bolts. 
     According to a further embodiment, the two longitudinal supports of the bogie frame are connected in a moveable fashion to the at least one transverse support such as, for example, via cylinder springs or rubber elements. This improves the running comfort of the undercarriage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The invention and advantageous embodiments of the invention will be described in more detail below with reference to the following figures, in which: 
         FIG. 1  shows by way of example an undercarriage having two drives according to the prior art, 
         FIG. 2  shows by way of example a wheelset having a cannon box drive in a plan view according to the prior art, 
         FIG. 3  shows by way of example a wheelset having an axial-riding drive in a plan view according to the prior art, 
         FIG. 4  shows by way of example a longitudinal section through an undercarriage having two cannon box drives which are connected in an oscillating fashion to a transverse support, in a basic illustration according to the prior art, 
         FIG. 5  shows by way of example a longitudinal section through an inventive undercarriage having a transverse support which is arranged centrally in the undercarriage frame and is connected to a locomotive body or railcar body via two tension/compression elements, in a basic illustration, 
         FIG. 6  shows by way of example an undercarriage according to the invention in a structural illustration and in a plan view, 
         FIG. 7  shows a section through the undercarriage according to  FIG. 6  along the sectional line VII-VII given in  FIG. 6 , 
         FIG. 8  shows a section through the transverse support along the sectional line VIII-VIII given in  FIG. 6 , in an enlarged illustration, and 
         FIG. 9  shows a section through the transverse support in an enlarged illustration corresponding to an alternative embodiment of the undercarriage. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows by way of example an undercarriage  1  having two drives  9  according to the prior art. 
     The undercarriage  1  which is shown comprises an undercarriage frame  2 , composed of two longitudinal supports  3  and a transverse support  4  connected thereto. In the example in  FIG. 1 , the undercarriage  1  has two wheelsets  7  which each have a wheelset shaft  8  and two wheels  5 . The wheelsets  7  are mounted in wheelset bearings  6  which, in the example in  FIG. 2 , are connected to the transverse support  4 . Two non-co-axial drives  9  are accommodated in the undercarriage frame  2 . In this case, the rotational axis of the traction motor  10  lies outside the rotational axis of the wheelset shaft  8 . Co-axial drives  9  are, for example, direct drives. For the application of longitudinal forces, that is to say of traction forces and compression forces, in particular of driving forces and braking forces of the undercarriage, the drive  9  which is located further toward the rear in the plane of the diagram is connected to a locomotive body or railcar body (not shown in more detail) via a tension/compression rod  15 . The two drives  9  can be connected to one another in an articulated fashion by means of a rod (not shown in  FIG. 1 ). 
     Furthermore, the two wheelsets  7  each have a brake device  12 . Primary springs are denoted by the reference symbol  13 . Said primary springs are arranged between the undercarriage frame  2  and the wheelset bearings  6  for the purpose of damping. The longitudinal supports  3  can be connected in an articulated fashion to the transverse support  4 . The undercarriage  1  can be connected, by means of large secondary springs  14  which are embodied as air springs, to a base plate of the rail vehicle, which is located above said secondary springs  14  and is not shown in more detail. 
       FIG. 2  shows by way of example a wheelset  7  with a cannon box drive  9  in a plan view according to the prior art. 
     As is shown by  FIG. 2 , the traction motor  10  is, as it were, seated on the wheelset shaft  8 . A cannon box tube  20 , which is co-axial with respect to the wheelset shaft  8 , can be seen between the traction motor  10  and the wheelset shaft  8 . The reference number  21  denotes two associated cannon boxes. The traction motor  10  drives, via a small wheel  23 , a large wheel  24  which is fixedly connected to the wheelset shaft  8 . The traction motor  10  also has a traction motor suspension system  22  by means of which the traction motor  10  can be connected in an articulated fashion to a transverse support  4 . 
       FIG. 3  shows by way of example a wheelset  7  with an axial-riding drive  9  in a plan view according to the prior art. 
     In the example in  FIG. 3 , the traction motor  10  is attached to a transverse support  4  (not illustrated) via traction motor suspension systems  29 . The traction motor  10  drives, via a motor shaft  25  and via a subsequent toothed coupling  26 , a transmission input shaft  27  which is connected to the small wheel  23 . The small wheel  23  drives a large wheel  24  which is fixedly connected in a rotationally fixed fashion to the wheelset shaft  8 . The housing (not described in more detail) of the drive  11  is connected to a cannon box tube  20  which is, for example, shorter compared to the cannon box tube  20  in  FIG. 2 . 
       FIG. 4  shows by way of example a longitudinal section through an undercarriage  1  with two cannon box drives  9  which are connected in an oscillating fashion to a transverse support  4 , in a basic illustration according to the prior art. The two traction motors  10  are connected to a cannon box tube  20  which is rotatably mounted co-axially in relation to the respective wheelset shaft  8 . Alternatively, just one driven wheelset  7  may be accommodated in the undercarriage  1 . It is also possible for a plurality of driven wheelsets  7 , for example three or four, to be accommodated. In addition to the driven wheelsets  7 , non-driven wheelsets  7  can also be arranged in the undercarriage  1 . The wheelsets  7  can be fixedly-mounted-wheel wheelsets or individually-mounted-wheel wheelsets. 
     In the example in  FIG. 4 , the longitudinal section extends through the geometric center of the undercarriage  1 . The plane of the diagram according to  FIG. 4  therefore corresponds to the longitudinal-sectional plane LSE. The longitudinal-sectional plane LSE extends perpendicular to a plane of the rails SE. An axis extending perpendicularly through this center is at the same time the axis of reflection of the undercarriage  1 . The word “perpendicular” denotes a parallel orientation to the surface normal of the plane of the rails SE on which the undercarriage  1  shown is located. 
       FIG. 5  shows by way of example a longitudinal section through an inventive undercarriage  1  with a transverse support  4  which is arranged centrally in the undercarriage frame  2  and is connected to a locomotive body or railcar body  16  via two tension/compression elements  41 ,  42  in a basic illustration. 
     According to the invention the transverse support  4  can be connected in an articulated fashion to the locomotive body or railcar body  16  by means of, in each case, at least one tension/compression element  41 ,  42  which is connected in an articulated fashion to an upper side OS and to a lower side US of the transverse support  4 . The illustrated tension/compression elements  41 ,  42  are preferably rigid tension/compression rods. As a result, by means of the arrangement according to the invention, torques DM and traction forces and compression forces FZ, FD which are applied to the transverse support  4  can be applied directly to the locomotive body or railcar body  16  while avoiding the bogie frame. 
     Furthermore, the reference symbol LA denotes a longitudinal-symmetry axis LA, and QA denotes a transverse-symmetry axis of the transverse support  4 . The longitudinal-symmetry axis LA extends in a cross-sectional plane QSE through the center of the undercarriage  1 . Furthermore the transverse support  4  is arranged in the undercarriage  1  in such a way that the transverse-symmetry axis QA extends in a longitudinal-sectional plane LSE through the center of the undercarriage  1 . In order to pass on with as little torque as possible the traction forces FZ and compression forces FD which are applied from the wheelset contact points, the longitudinal-symmetry axis LA and the transverse-symmetry axis QA of the transverse support  4  also extend in a plane extending through the rotational axes RA of the wheelset shafts  8 . Perpendicular sections through the transverse support  4  along the longitudinal-symmetry axis LA and the transverse-symmetry axis QA have at least predominantly a rectangular cross section. 
     The tension/compression elements  41 ,  42  which are shown in  FIG. 5  each have a first end  41   a ,  42   a . Second ends  41   b ,  42   b  form in each case a joint  47 ,  48  with a locomotive-side or railcar-body-side bearing (not illustrated in more detail). Furthermore, in each case a bearing block or a bracket  43 ,  44  is arranged on the upper side OS and on the lower side US of the transverse support  4 , with the first ends  41   a ,  42   a  of the tension/compression elements  41 ,  42  forming in each case one joint  45 ,  46  with the respective bearing block  43 ,  44 . The previously described joints  45  to  48  are preferably spherical bearings or ball-and-socket joints. 
     In the example in  FIG. 5 , the joints  45 ,  46  are arranged both in a cross-sectional plane QSE and in a longitudinal-sectional plane LSE through the center of the undercarriage  1 . The tension/compression elements  41 ,  42  which are connected in an articulated fashion thereto extend parallel to one another and also in mirror-inverted fashion with respect to the plane extending through the rotational axes RA of the wheelset planes  8 . 
     Two drives  9  with one traction motor  10  and one transmission  11  each are accommodated in the undercarriage frame  2 . The drives  9  are cannon box drives  9  whose traction motors  10  are connected to a cannon box tube  20  which is rotatably mounted co-axially with respect to the wheelset shaft  8 . Each traction motor  10  has, for applying the torque originating from it or from the drive  9 , a torque support  51  which is connected in an articulated fashion to the transverse support  4 . Braking torques, which originate, for example, from a mechanical brake device arranged in the wheelset  7 , can also be applied to the transverse support  4  via the torque support  51 . The torque supports  51  which are shown are connected in an articulated fashion to the lower side US of the transverse support  4 . 
     Alternatively, axial-riding drives  9  with one traction motor and one transmission  11  each can be accommodated in the undercarriage frame  2 , with the traction motors  10  then in particular being connected in a transversely elastic fashion to the transverse support  4 . In this drive variant it is particularly advantageous if the one transmission has an even number of transmission stages, in particular has two stages, and the other transmission has an uneven number of transmission stages, in particular has a single stage, with the same transmission ratio. As a result, the engine torques originating from the two traction motors  10  which are mounted on the transverse support  4  largely compensate one another. In order to apply the torques originating from the transmissions  11  to the transverse support  4 , a torque support, which is itself connected in an articulated fashion to the transverse support  4 , is mounted on each axial-riding transmission  11 . 
       FIG. 6  shows by way of example an undercarriage  1  according to the invention in a structural illustration and in a plan view. 
     The central transverse support  4  which is shown has a longitudinal-symmetry axis LA and a transverse-symmetry axis QA which are arranged in the cross-sectional plane QSE and in the longitudinal-sectional plane LSE through the (geometric) center of the undercarriage  1 . The transverse support  4  is connected in a movable fashion to two longitudinal supports  3  of the undercarriage frame  2  via two guide elements  60 . In addition, secondary springs  14  are arranged on the upper side OS of the transverse support  4 . Said secondary springs  14  serve to provide suspension to the locomotive body or railcar body  16  (not illustrated) which is “located above them”. 
     In the projected geometric center of the undercarriage there is, on the upper side OS of the transverse support  4 , a bearing block  43  to which the upper tension/compression element  41  is connected in an articulated fashion. The other end of the upper tension/compression element  41  is also connected in an articulated fashion to a locomotive body or railcar body  16  (illustrated only in a rudimentary fashion). The lower tension/compression element  42  which is arranged horizontally parallel to the upper tension/compression element  41  is concealed in this illustration by the upper tension/compression element  41  and therefore is not visible. In the structural configuration of the undercarriage  1  which is shown, the tension/compression elements  41 ,  42  are embodied as tension/compression rods. 
     Two cannon box drives  9  with one traction motor  10  and one transmission  11  each are accommodated in the undercarriage  1 . The traction motors  10  are, on the one hand, connected fixedly to a cannon box tube  20 , with the cannon box tube  20  being embodied co-axially with respect to the wheelset shaft  8 . In each case two cannon boxes  21  are arranged between the wheelset shaft  8  and the cannon box tube  20 , and they each form an integral structural unit with the wheelset bearings  6 . On the other hand, the two traction motors  10  are connected in an articulated fashion to the side region of the transverse support  4  via one torque support  51  each in order to apply the traction-motor-side or drive-side torques. The torque supports  51  are also connected in an articulated fashion to the transverse support  4  via one pendulum  55  each, which pendulums  55  are, however, not visible in the present illustration. The torque supports  51  are illustrated in detail in the following  FIG. 7  and  FIG. 8 . Furthermore, the wheelsets  7  are connected to the transverse support  4  via wheelset connecting rods  49 . The wheelset bearings  6  can, as shown in  FIG. 6 , be damped in relation to the respective wheelset connecting rod  49  using, for example, primary springs  13  which are embodied as cylinder springs. 
     In the example in  FIG. 6 , the transverse support  4  has a maximum width QB. In the projected illustration of the undercarriage  1 , the transverse support  4  is located between the wheelsets  7 , viewed in the longitudinal extent LR of the undercarriage  1 . AR denotes the distance of the rotational axes RA of the wheelset shafts  8  from one another, and AB denotes the distance of the longitudinal-symmetry axis LA of the transverse support  4  from the bearing axis of the joint  52  in the longitudinal extent LR of the undercarriage  1 . The ratio of the distance AB to the maximum width QB of the transverse support  4  is less than ½. In particular, the ratio has a value in a range from ¼ to ⅓, so that virtually torque-free application of the traction-motor-side or drive-side torques to the transverse support  4  can take place. Here, application of the torques as closely as possible to the longitudinal-symmetry axis LA of the transverse support  4  is desirable. 
     Furthermore, in order to improve the running properties of the undercarriage  1  which is shown in the example in  FIG. 6 , the wheelset bearings  6  in the undercarriage frame  2  are each connected to the transverse support  4 , in particular connected laterally to the transverse support  4 , by means of a wheelset connecting rod  49 . 
       FIG. 7  shows an illustration of a section through the undercarriage  1  according to  FIG. 6  along the sectional line VII-VII plotted in  FIG. 6 . 
     The two tension/compression rods  41 ,  42  which are arranged one on top of the other and are arranged parallel to the plane of the rails SE can be seen in the right-hand part of  FIG. 7 . The reference symbol FZ denotes a traction force which acts on the wheelset shaft  8  and is brought about by the drives  9 . The reference symbol FD denotes a compression force which acts on the wheelset shaft  8 , in the opposite direction to the traction force FZ. The drive torque which acts on the respective wheelset shaft  8  is denoted by the reference symbol DM. The traction force FZ and compression force FD are, in particular driving forces or braking forces of the drives  9  depending on the direction of travel of the undercarriage. As is shown further in  FIG. 7 , the torque DM and the longitudinal forces FZ, FD can be applied virtually completely to the locomotive body or railcar body  16  via the two tension/compression rods  41 ,  42 . 
     In this illustration, the articulated connection of the traction motors  10  via, in each case, one torque support  51  and via, in each case, one pendulum  55  can be seen clearly in the side region of the transverse support  4 . 
       FIG. 8  shows an illustration of a section through the transverse support  4  along the sectional line VIII-VIII plotted in  FIG. 6 , in an enlarged illustration. 
     In this illustration it is apparent that in each case one bracket  56  is arranged in the side region of the transverse support  4 . The upper end of the pendulum  55  is accommodated in an articulated fashion in the bracket  56 , while the lower end of the pendulum  55  is connected in an articulated fashion to the torque support  51  of the respective traction motor  10 . The oscillating connection permits, to a certain degree, vehicle movement dynamics compensation of transverse movements of the traction motor  10 . As a result, only parts of the drive masses are suspended in a primary fashion in the vertical direction on the transverse support  4 . They are therefore not included in the unsprung part of the wheelset masses. 
     Furthermore,  FIG. 8  shows the connection of the wheelset connecting rods  49  in the lateral region of the transverse support  4 . The wheelset connecting rods  49  can be connected to the transverse support  4  by means of a comparatively rigid connecting element such as, for example, a rubber/metal element. 
       FIG. 9  shows an illustration of a section through the transverse support  4  corresponding to an alternative embodiment of the undercarriage, in an enlarged illustration. 
     As is shown by  FIG. 9 , in each case a bearing block  43 ,  44  for the articulated connection of the tension/compression elements  41 ,  42  is arranged on the upper side OS and lower side US of the transverse support  4 . In addition, in each case a traction force connecting rod  57  is arranged in an articulated fashion between the lower bearing block  44  and the torque supports  51 . The traction force connecting rods  57  have a longitudinal axis which each extend in a longitudinal-sectional plane through the center of the undercarriage  1 . Said traction force connecting rods  57  are also arranged parallel to a plane extending through the rotational axes of the wheelset shafts and between the lower side US of the transverse support  4  and the lower tension/compression element  42  or the lower tension/compression rod  42 . With such an arrangement of the traction force connecting rods  57 , comparatively low bending torques result owing to the traction forces and braking forces about the vertical axis of the transverse support  4  compared to the application of these forces via the wheelset connecting rods  49 . 
     As is shown further by  FIG. 9 , each end of the two traction force connecting rods  57  which are shown has a joint  58 ,  59 . The joints  58 ,  59  may be, for example, a spherical bearing, a ball bearing or else a rubber/metal element. 
     The wheelset connecting rods  49  are preferably arranged parallel to the traction force connecting rods  57 . As a result of the apportionment of forces, the wheelset connecting rods  49  can be made less rigid with respect to the connection to the transverse support compared to the solution without traction force connecting rods  57 . This is more favorable in terms of technical running properties when the undercarriage  1  travels through a bend.