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(11) | EP 0 646 510 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Device for orientating the axles of a railway vehicle on bends |
| (57) A device for orientating, during travel along a curved track (13), the axles (7,
8) of a railway vehicle (1, 2) connected to at least one similar vehicle to form a
train, each vehicle (1, 2) comprising, for its guiding and support along said track,
means which contain one axle (7, 8), or several axles (7, 8) possibly associated with
each other within a possible bogie, and which are positioned in proximity to the ends
(9, 10) of the vehicle; at least one of the guide means of each vehicle (1, 2) forms
part of a corresponding articulated structure connected to transmission and connection
means (70, 71) which couple two adjacent vehicles (1, 2) and connect the articulated
structures associated with the two vehicles together, said means (70, 71) providing
articulated connection between the vehicles and, when on a bend, generating a movement
of their axles (7, 8) which causes these latter to assume a position inclined to the
longitudinal axis (F) of the vehicle (1, 2) and enable the wheels supported by them
to follow the radius of curvature of the track (3). |
[0002] During the movement of an at least two-vehicle train (railway, underground or tramway) along a curved track (ie on a bend), mutual stresses are known to be generated between the wheels of each vehicle and the rails, leading to wear of the contacting parts and hence the need for maintaining these parts at relatively frequent time intervals. This involves considerable cost.
[0003] Contact between the wheels and track rails also gives rise to squealing and vibration which negatively influence the travelling comfort of vehicle passengers.
[0004] In an attempt to overcome such problems, known arrangements associate the axles of each pair of wheels with movable bogies pivoted to the vehicle body and free to move about the pivot, or provide single axles interposed between the ends of connected vehicles and comprising means for their connection to both vehicles.
[0005] The first known arrangement (used on railway trains, underground trains and trams) only limits this problem without properly solving it. In this respect, movable bogies to not achieve optimum reduction in the noise and vibration transmitted to passengers by the wheels when the vehicle or coach is travelling on a bend unless there is a considerable use of special soundproofing means and vibration absorption means interposed between the bogie and the coach body.
[0006] In addition, the presence of bogies in proximity to the ends of the vehicle means that its floor has to be raised, with obvious consequences for the overall structure and the total height.
[0007] The second arrangement (single axle with means for its connection between adjacent vehicles) solves some of the problems connected with the use of bogies (such as the increase in the vehicle height), but gives rise to parasite movements of the axles due to the mutual displacement which normally occurs between vehicles along a curved path. This has consequences both for the vehicle running stability and for the comfort of vehicle passengers.
[0008] An object of the present invention is therefore to provide a device for orientating the support and guide means (comprising one or more axles associated with each other in a bogie, wheels, brake discs mounted on the wheels, suspension members, shock absorbers, braking members and usual brake pads) of a railway vehicle which overcomes the aforesaid drawbacks in an optimum manner during the movement of the vehicle along a curved track.
[0009] A particular object of the present invention is to provide a device by which track and wheel flange wear is drastically reduced on bends, with evident advantage in terms of maintenance costs.
[0010] A further object is to provide a device by which the noise and vibration is drastically reduced on bends, with evident advantage to the vehicle environmental impact and comfort on board.
[0011] A further object is to provide a device which can replace conventional railway bogies by guided axles if the load per axle of the vehicle allows it, with evident advantage to vehicle cost and weight.
[0012] A further object is to provide a device which enables the vehicle floor level to be reduced by virtue of the fact that wheels and suspensions housed under the seats undergo only small movement relative to the vehicle body, so leaving a sufficient corridor for passage.
[0013] These and further objects which will be apparent to the expert of the art are attained by a device in accordance with the accompanying claims.
[0014] The present invention will be more apparent from the accompanying drawing, which is provided by way of non-limiting example and in which:
Figure 1 is a schematic view of two coupled railway vehicles during travel along a curved path;
Figure 2 is a schematic view of the device applied to coupled vehicles;
Figure 3 is an enlarged view of the part indicated by A in Figure 2;
Figure 4 is a schematic view of the essential features of the invention;
Figure 5 is a view from above of an embodiment of the device according to the invention;
Figure 6 is a section on the line 6-6 of Figure 5;
Figures 7, 8 and 9 are a front, side and top plan view of a part of the device according to the invention.
[0015] Figure 1 shows two coupled railway vehicles 1 and 2 during travel along a curved track 3. Each vehicle 1 and 2 comprises in the example single axles 7 and 8 positioned in proximity to its opposing ends 9 and 10; each of these axles is guided by a device according to the invention to enable them to incline to the longitudinal axis of the vehicle when this travels along a curved track portion in order to enable the usual wheels to follow the tracks. Specifically, to achieve this inclination, the device utilizes the relative rotation which occurs between the bodies 1A and 2A of the vehicles 1 and 2 when on the bend.
[0016] With reference to Figures 2 to 9 (in which parts corresponding to those of Figure 1 are indicated by the same reference numerals), the device according to the invention comprises elements common to the vehicles 1 and 2 which will be indicated respectively by numerals followed by the letter A (vehicle 1) or B (vehicle 2). However, for simplicity of description that particular device of Figures 5-9 applied to the vehicle 2 is described, with only those parts common with the device of vehicle 1 being followed by a letter. Normal vehicle parts are merely numbered.
[0017] The axle 8 of the vehicle 2 supports usual wheels 14 at its ends 12 and 13. Axle boxes 15 are present at these ends and cooperate with usual suspension springs 16; usual shock absorbers 17 and 18 of known operation are also present at these ends. The axle 8 is associated with the device according to the invention comprising a rocker arm 20B pivoted on its centre line 21B and supported by fixed arms 22 and 23 forming part of the body 2A of the vehicle 2. These arms carry at their free end a C-shaped member 50 to which the middle of the rocker arm 20B is connected by a pin 60.
[0018] The ends 24B and 25B of the rocker arm are hinged at 26B to arms 27B hinged at 28B to slides 29B slidable along longitudinal guides (parallel to the vehicle axis F) 30B associated with the vehicle bodies 2A. To each slide there are hinged two connecting rods 31B and 32B hinged at 33B to a corresponding guide member 34B for a corresponding axle box 15. This member, the connecting rods and the slide define a guide parallelogram between this latter and the member 34B. Each guide member supports corresponding shock absorbers 17 and 18 and a usual guide 35 for a brake 36 associated with the corresponding wheel 14. Said member enables relative movement of the corresponding axle box 15 to take place by way of usual bearings (not shown).
[0019] The axle box support members 34B also carry a bracket 37 arranged to cooperate with usual buffers 38 provided to the side of the wheels to receive the lateral stresses arising from forces transverse to the axis F of the vehicle 2 during the movement of this latter along the track 3.
[0020] Each spring 16 is associated with the vehicle body, which comprises an intermediate portion 55 located between the wheels 14 and depressed relative to lateral portions 56 to which the springs 16 are connected.
[0021] These latter, besides acting as usual suspensions, tend to maintain the axis W of the axle 8 in the rest position, ie perpendicular to the vehicle axis F and to return the axle 8 to this position after the vehicle has travelled along a curved track portion 3. This is because of the natural lateral elasticity of the springs 16. Should lack of symmetry exist in the behaviour of the axle 8 during movement on bends (which would occur if the axle 8 is connected to another axle of the vehicle where this is at the end of the railway train, as will be seen), additional auxiliary springs (equivalent members) 40B are provided between the vehicle body and the rocker arm 20B. These springs are preferably located in a position symmetrical about the C-shaped member 50 which supports the rocker arm. At this C-shaped member there is also provided a buffer element 41B (for example an elastic or rubber body) to absorb those stresses acting on the vehicle along the direction of its axis F (due for example to impact between two adjacent vehicles). This buffer can act directly on the rocker arm 20B or not.
[0022] It should be noted that the slides 29B directly damp the oscillatory movements along the direction of the axis F.
[0023] Moreover, advantageously each slide 29A, B can be associated with a shock absorber 44 fixed to the body of the relative vehicle (as shown in Figures 2 and 3) to compensate and further damp any oscillations undergone by the slides during vehicle movement.
[0024] A member or shaft 70 connecting together the devices of the aforesaid type associated with the adjacent vehicles 1 and 2 is connected to the C-shaped member by the pin 60 and a ball joint 42. The shaft 70 is hinged by the pin 60 to the rocker arms 20A and 20B of the two adjacent vehicles (see Figures 2-4).
[0025] A further connection shaft 71 is hinged to the rocker arms 20A and 20B (in known manner, for example in proximity to their ends 24A and 24B) of the two adjacent vehicles to form with said rocker arms and with the shaft 70 an articulated guide parallelogram system which, when in use, enables the axles 7 and 8 of the two vehicles 1 and 2 to orientate themselves and follow the curved track with their wheels 14. In this case the axis W of said axles inclines to the vehicle axis F so that said wheels follow the track 3 in the best manner.
[0026] Finally, as shown in Figures 2 and 3 a rear end vehicle has that axle 7 close to the (free) end 9 connected to the other axle 8 by a motion transmission and reversal system; this can be achieved for example by connecting close to the end 10 of the vehicle two pulleys 80 with which there cooperate crossed cables 81 connected to the ends 12 and 13 of the axle 7. Other arrangements are however possible, such as those comprising connection rods and reversing linkages, flexible cables or usual hydrostatic transmissions.
[0027] In addition, the axle 7 at the free end 9 can be advantageously connected by pairs of connecting rods 700 to slides 710, these latter connected by connecting rods to the rocker arm 720 hinged to the vehicle body at 730.
[0028] It will be assumed that the device of the invention applied to adjacent vehicles and connected together by shafts 70 and 71 is now to be used.
[0029] During straight-line movement of the vehicles and in the absence of relative transverse movement between the two coupled vehicle bodies, the rocker arms 20A and 20B are perpendicular to the longitudinal axis F of each vehicle and by means of the arms 27A and 27B maintain the lines Q joining the pairs of slides 29A and 29B perpendicular to the longitudinal axis F of each vehicle.
[0030] By means of the pairs of connecting rods 31A, B and 32A, B the pairs of slides each maintain the corresponding pairs of axle boxes 15 in their correct position.
[0031] Even when relative transverse movement between the two coupled vehicle bodies is present, the guide parallelogram maintains the rocker arms 20A and 20B perpendicular to the longitudinal axis of the vehicle, and in the aforegoing manner the axle boxes remain in their correct position.
[0032] The device therefore does not give rise to parasite rotation of the axles 7 and 8, and any hunting motion of these latter (due to attainment of critical speeds) is opposed and absorbed by the shock absorbers 44.
[0033] When the train of vehicles reaches the curved track portion, the guide parallelogram (comprising the shafts 70 and 71 and the two rocker arms 20A and 20B) assumes relative to the two coupled vehicle bodies an intermediate position provided by the symmetry of the elastic return action of the suspension springs 16 for the guided axles 7, 8 and, if provided, of the auxiliary springs 40A, B. Consequently the line E perpendicular to the shaft 70 passing through its central point extends radially, ie passes through the centre of the bend, and the rocker arms of the guide parallelogram, by remaining parallel to this perpendicular line, assume a "nearly radial" position, with a slight excess rotation beyond the rigorously radial position. The arms 27A, B, positioned slightly inclined, transmit to the slides the component of the movement in the direction parallel to the vehicle longitudinal axis so as to position the pairs of slides 29A, B. These move along the respective guides 30A, B to each transmit their position, via the connecting rods 31A, B and 32A, B, to the corresponding pairs of axle boxes. Consequently the axles 7 and 8 rotate about the point of intersection of their axis W and the axis F of the vehicle to which it pertains, to undergo radial positioning with respect to the vehicle to which they pertain.
[0034] In the front and rear end carriages of the train, the rotation of the axles connected by the device of the invention is transmitted reversed to the free end axles (for example by the pulleys 80 and cables 81) so as to orientate them in the correct direction.
[0035] The described device enables:
a) traditional bogies to be replaced by guided axles, in those cases in which the load per vehicle axle allows it, with evident advantage in terms of vehicle cost and weight;
b) track and wheel flange wear on bends to be drastically reduced, with evident advantage in terms of maintenance costs;
c) noise and vibration on bends to be substantially reduced, with evident advantage in terms of vehicle environmental impact and comfort on board;
d) the vehicle floor level to be reduced by virtue of the fact that wheels and suspensions housed under the seats undergo only small movement relative to the vehicle body, so leaving a sufficient corridor for passage.
[0036] A device applied to support and guide means of vehicles defined as single-axle has been described.
[0037] In addition to single axles, the described device also enables railway bogies to be guided should it be necessary to use these. In such a case the advantages of the aforesaid points b) and c) are partially obtained.
[0038] These advantages could be totally achieved by also using, in addition to the aforedescribed device able to radially orientate the transverse axis of bogies on bends, a primary suspension (springs 16) with a longitudinal elasticity sufficient to enable the bogie axles to undergo the further radial orientation required by the bogie wheel base and automatically generated by the wheel taper.
[0039] It is apparent that, in guiding the bogie, the pairs of connecting rods 31A, B and 32A, B intended to react against reaction moments deriving from braking or traction, are no longer required. The bogie can be directly connected to the arms 27A, B positioned parallel to the axis F of the corresponding vehicle.
[0040] The described device can also be associated with an axle which receives its movement from a usual motor mounted under the vehicle body. In this case the members 34A, B are structurally modified to receive the usual motion transmission elements, but must again be connected to the connecting rods 31A, B and 32A, B.
1. A device for orientating, during travel along a curved track, the axles of a railway
vehicle connected to at least one similar vehicle to form a train, each vehicle comprising,
for its guiding and support along said track, means which contain one axle or several
axles possibly associated with each other within a possible bogie, and which are positioned
in proximity to the end of the vehicle, characterised in that at least one of the
support and guide means of each vehicle (1, 2) is guided by a corresponding articulated
structure connected to transmission and connection means (70, 71) which couple two
adjacent vehicles (1, 2) and connect the articulated structures associated with the
two vehicles together, said means (70, 71) providing articulated connection between
the vehicles and, when on a bend, generating a movement of their axles (7, 8) which
causes these latter to assume a position inclined to the longitudinal axis (F) of
the vehicle (1, 2) and enable the wheels connected to them to follow the radius of
curvature of the track (3).
2. A device as claimed in claim 1, characterised in that a part (20A, 20B) of each articulated
structure of each vehicle (1, 2) defines with the transmission and connection means
(70, 71) an articulated quadrilateral for guiding the support and guide means (7,
8) of said vehicle.
3. A device as claimed in claim 1, characterised in that that part of each articulated
structure connected to the transmission and connection means (70, 71) is a rocker
arm (20A, 20B).
4. A device as claimed in the preceding claims, characterised in that the transmission
and connection means are at least a first and a second shaft (70, 71) hinged to the
rocker arms (20A, 20B) of the articulated structures of adjacent vehicles (1, 2).
5. A device as claimed in claim 4, characterised in that the first shaft (70) is hinged
to at least one member (50) supported by fixed arms (22, 23) of the bodies (2A) of
at least one vehicle (2), to said member (50) there being also connected the corresponding
rocker arm (20B) of said vehicle, preferably at a central part thereof.
6. A device as claimed in claim 4, characterised in that the second shaft (71) is hinged
to each rocker arm (20A, 20B) at one of its ends.
7. A device as claimed in claims 1 and 4, characterised in that the articulated structure
associated with each vehicle (1, 2) comprises the rocker arm (20A, 20B) and at least
one pair of arms (27A, 27B) hinged to said rocker arm (20A, 20B) and to the support
and guide means (7, 8) of the vehicle (1, 2).
8. A device as claimed in claim 7, characterised in that the arms (27A, 27B) hinged to
the rocker arm (20A, 20B) are connected to sliding elements (29A, 29B) movable along
guides rigid with the body (1A, 2A) of the corresponding vehicle (1, 2) and arranged
parallel to its longitudinal axis (F), said elements being associated, via transmission
elements (31A, 31B; 32A, 32B), with the support and guide means (7, 8) of said vehicle
(1, 2).
9. A device as claimed in claim 8, characterised in that the transmission means (31A,
31B; 32A, 32B) are connected to end elements (34A, 34B) of the vehicle support and
guide means (7, 8).
10. A device as claimed in claim 8, characterised in that the transmission members are
arms (31A, 31B; 32A, 32B), of which at least one is associated with each movable element
(29A, 29B).
11. A device as claimed in claim 8, characterised in that each transmission member comprises
arms (31A, 31B; 32A, 32B) positioned mutually superposed and parallel and hinged to
the corresponding sliding element (29A, 29B) and to the corresponding end element
(34A, 34B) of the support and guide means (7, 8) of each vehicle (1, 2), said members
and the elements associated with them defining an articulated quadrilateral structure.
12. A device as claimed in claim 9, characterised in that each end element of the support
and guide means (7, 8) of each vehicle (1, 2) is at least one member (34A, 34B) rotatably
supporting a usual corresponding end bushing (15) for said means, said member supporting
usual braking elements (36) for the wheels (14) of the vehicle (1, 2).
13. A device as claimed in claim 1, characterised by comprising elastic means (16; 40A,
40B) for returning the support and guide means (7, 8) of each vehicle to its rest
position after travelling along a curved track portion.
14. A device as claimed in claim 13, characterised in that the elastic return means are
at least the usual suspension springs (16) associated with the support and guide means
(7, 8) of each vehicle (1, 2).
15. A device as claimed in claim 13, characterised in that the elastic return means are
members (40A, 40B) cooperating with each rocker arm (20A, 20B) defining with the transmission
means (70, 71) the articulated guide quadrilateral.
16. A device as claimed in claim 1, characterised by comprising means (41A, 41B) associated
with each articulated guide quadrilateral to support and/or compensate and/or damp
those stresses directed along the axis (F) of each vehicle.