U.S. patent application number 11/700165 was filed with the patent office on 2007-08-16 for axle for rail vehicle having a low-level floor, bogie and corresponding rail vehicle.
This patent application is currently assigned to ALSTOM TRANSPORT SA. Invention is credited to Christophe Eche, Jean-Christophe Loiseau, Alain Rodet.
Application Number | 20070186803 11/700165 |
Document ID | / |
Family ID | 37307053 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070186803 |
Kind Code |
A1 |
Rodet; Alain ; et
al. |
August 16, 2007 |
Axle for rail vehicle having a low-level floor, bogie and
corresponding rail vehicle
Abstract
An axle for a rail vehicle including a central shaft, two wheels
which are connected in terms of rotation by the shaft and two
bearings, each wheel being mounted so as to rotate relative to a
bearing about the axis Y of the wheels. The axle further includes
at least one cross-piece for reinforcement of the axle in terms of
flexion, this cross-piece rigidly connecting the two bearings.
Inventors: |
Rodet; Alain; (Chalon Sur
Saone, FR) ; Loiseau; Jean-Christophe; (Le Creusot,
FR) ; Eche; Christophe; (Le Creusot, FR) |
Correspondence
Address: |
DAVIDSON, DAVIDSON & KAPPEL, LLC
485 SEVENTH AVENUE, 14TH FLOOR
NEW YORK
NY
10018
US
|
Assignee: |
ALSTOM TRANSPORT SA
Levallois-Perret
FR
|
Family ID: |
37307053 |
Appl. No.: |
11/700165 |
Filed: |
January 30, 2007 |
Current U.S.
Class: |
105/453 |
Current CPC
Class: |
B61D 13/00 20130101;
B61F 5/50 20130101 |
Class at
Publication: |
105/453 |
International
Class: |
B61F 1/00 20060101
B61F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 30, 2006 |
FR |
06 00834 |
Claims
1-17. (canceled)
18. An axle for a rail vehicle comprising: a central shaft; two
wheels having a wheel axis; connected in terms of rotation by the
central shaft; two bearings; each wheel being mounted so as to
rotate relative to a respective bearing of the two bending about
the wheels axis, the central shaft extending along the wheel axis;
and at least one cross-piece for reinforcement of the axle in terms
of flexion, the cross-piece rigidly connecting the two
bearings.
19. The axle as recited in claim 18 wherein the cross-piece is
located at a height lower than a height of the shaft, relative to
an upper edge of rails for the rail vehicle.
20. The axle as recited in claim 18 wherein the shaft extends
inside the cross-piece.
21. The axle as recited in claim 18 wherein the shaft has a
diameter of between 60 and 140 mm.
22. The axle as recited in claim 19 wherein the shaft has a
diameter of between 60 and 140 mm.
23. The axle as recited in claim 20 wherein the shaft has a
diameter of between 60 and 140 mm.
24. The axle as recited in claim 18 wherein the cross-piece has a
cross-section at least equal to that of the shaft.
25. The axle as recited in claim 19 wherein the cross-piece has a
cross-section at least equal to that of the shaft.
26. The axle as recited in claim 20 wherein the cross-piece has a
cross-section at least equal to that of the shaft.
27. The axle as recited in claim 21 wherein the cross-piece has a
cross-section at least equal to that of the shaft.
28. The axle as recited in claim 22 wherein the cross-piece has a
cross-section at least equal to that of the shaft.
29. The axle as recited in claim 23 wherein the cross-piece has a
cross-section at least equal to that of the shaft.
30. The axle as recited in claim 20 wherein the cross-piece
defines, with the bearings, a sealed space around the shaft.
31. A bogie for a rail vehicle comprising: a bodywork; and at least
one axle supporting the bogie as recited in claim 18.
32. A rail vehicle comprising: a body; and at least one bogie for
supporting the body as recited in claim 31.
33. The rail vehicle as recited in claim 32 wherein the wheels have
a diameter of between 530 and 660 mm, and further comprising a
first floor having a height of between 385 and 510 mm above an
upper edge of rails for the vehicle in the region of the bogie.
34. The rail vehicle as recited in claim 33 further comprising a
second floor having a height of between 335 and 375 mm, the first
floor and second floor being connected by a ramp with an
inclination of between 5 and 10%.
Description
[0001] This claims priority to the French application number 06
00834, filed Jan. 30, 2006, and hereby incorporated by reference
herein.
TECHNICAL FIELD
[0002] The present invention relates to an axle for a rail vehicle
of the type comprising a central shaft, two wheels which are
connected in terms of rotation by the shaft and two bearings, each
wheel being mounted so as to rotate relative to a bearing about the
axis of the wheels.
BACKGROUND TO THE INVENTION
[0003] Axles of this type are conventionally used for rail
vehicles, in particular for urban rail transport of the tramway
type. These conventional axles are provided on bogies which support
vehicle bodywork whose floor is generally, above the axles, at a
height of 520 mm above the upper edge of the rails with standard
wheels having a diameter of 590 mm in the new state. In an urban
environment, and therefore with no platform, this floor height
poses access problems for passengers, for example, in a
tramway.
[0004] Document EP 1 171 336 describes a rail vehicle having, on
the one hand, a lowered floor above the axles, having a height,
above the upper edge of the rails, of 450 mm owing to wheels which
have a smaller diameter than the standard diameter and, on the
other hand, a floor zone of lesser height, at approximately 355 mm
above the rails, connected by means of ramps to the floor zone
above the axles, this zone of lesser height being a zone which
facilitates access for passengers.
[0005] There are also crank axles. Axles of this type described,
for example, in document EP 911 239, are located below the rotation
axis of the wheels, allowing the floor to be lowered in the region
of the axles of the wheels owing to a complex arrangement of
transmission of engine torques to the wheels. These axles comprise
bevel gears and/or step-down gears which allow a rotary connection
shaft to be used which is offset parallel with the rotation axis of
the wheels.
[0006] The disadvantages of these two types of axle are, firstly,
the need to use non-standard wheels and, secondly, a high level of
complexity and therefore high production cost for the axles.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is therefore to provide a
vehicle having a lowered floor without the above-mentioned
disadvantages.
[0008] The present invention provides an axle for a rail vehicle of
the above-mentioned type, wherein it further comprises at least one
cross-piece for reinforcement of the axle in terms of flexion, this
cross-piece rigidly connecting the two bearings.
[0009] According to other features of the invention: [0010] the
cross-piece is located at a height lower than the height of the
shaft, relative to the upper edge of the rails; [0011] the diameter
of the shaft is between 60 and 140 mm; [0012] the cross-piece has a
cross-section which is at least equal to that of the shaft; [0013]
the cross-piece is hollow and the shaft extends inside the
cross-piece; [0014] the cross-piece defines, with the bearings, a
sealed space around the shaft.
[0015] The present invention also provides a bogie which comprises
a bodywork and at least one axle which supports the bogie as
defined above.
[0016] The present invention also provides a rail vehicle which
comprises a body and at least one bogie for supporting the body as
defined above.
[0017] According to other features of the present invention, in the
case, for example, of a tramway: [0018] the wheels have a diameter
of between 530 and 660 mm and the vehicle comprises a first floor
having a height of between 385 and 510 mm above the upper edge of
the rails in the region of the bogie; and [0019] the rail vehicle
comprises a second floor having a height of between 335 and 375 mm,
the two floors being connected by means of a ramp with an
inclination of between 5 and 10%.
BRIEF DESCRIPTION OF THE FIGURES
[0020] The present invention will be better understood from a
reading of the following description, given purely by way of
example and with reference to the appended drawings, in which:
[0021] FIG. 1 is a schematic plan view of a bogie which is provided
with two axles according to the invention;
[0022] FIG. 2 is a schematic front view substantially in accordance
with the arrow II of FIG. 1, illustrating an axle;
[0023] FIG. 3 is a profile view of a rail vehicle having two
different floor levels; and
[0024] FIG. 4 is a view similar to that of FIG. 2, illustrating an
axle according to a variant of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] The bogie 1 of FIG. 1 substantially comprises a bodywork 5,
two pairs of wheels 9, each of which is integrated in an axle 11,
and a suspension system 15 which is interposed between the axles 11
and the bodywork 5.
[0026] The bodywork 5 is generally H-shaped having two longitudinal
members 17 which are parallel with the longitudinal axis X of the
bogie 1. Each longitudinal member 17 has two ramped zones 18, the
central portion of the longitudinal member between the two axles 11
being lower than the ends of the longitudinal member. The two
longitudinal members 17 are connected by means of a transverse
central beam 19 which is perpendicular relative to the longitudinal
members 17. The bodywork 5 is intended to support a body 20 of a
vehicle, for example a tramway vehicle. The body 20 is, for
example, articulated to the centre of the beam 19.
[0027] Each axle 11 comprises a central shaft 21 which extends
transversely along the entire width of the axle. It connects the
two wheels 9 in terms of rotation and extends along the axis Y of
rotation which is common to both wheels.
[0028] Two bearings 22, each located against a wheel 9, support the
bodywork 5. Each wheel 9 is mounted so as to rotate relative to a
bearing 22.
[0029] A cross-piece 23 which can be seen in FIG. 2 and which is,
for example, cylindrical with a rectangular cross-section, rigidly
connects the two bearings 22 to each other by means of the lower
ends thereof, in vertical alignment with the shaft 21. The
cross-piece 23 is thus parallel with the rotation axis Y of the
wheels 9 and located below the shaft 21. It is slightly spaced from
the shaft at a distance i which is advantageously, for a tramway
between 80 and 120 mm, for example, in the order of 100 mm.
[0030] The two bearings 22 each have a support surface for the
suspension system 15.
[0031] The wheels 9 have a diameter D which is advantageously
between 530 mm and 620 mm, for example, in the order of 590 mm. 590
mm is the standard diameter for tramway wheels in the new state.
The diameter of standard wheels 9 may become as low as 530 mm with
wear. The wheels 9 are placed on rails 24.
[0032] The diameter d of each shaft 21 is advantageously between 60
mm and 140 mm, for example, in the order of 100 mm.
[0033] The cross-piece 23 has a cross-section which is at least
equal to that of the shaft 21.
[0034] Elements for controlling the bogie, such as a speed
step-down gear 26 or a motor, for example, are arranged in one or
more bearings 22.
[0035] The floor 31 of the body 20 of the vehicle, located just
above the axle 11, is remote from the axle 11 with a spacing i. The
spacing i, which corresponds to the deflection of the suspensions
15, is advantageously between 40 and 80 mm, in the order of 60 mm,
for example. The floor 31 has a thickness e which is advantageously
between 30 and 70 mm, for example, in the order of 50 mm.
[0036] The inner side of the floor 31 is thus at a height h from
the peak of the rail which is a function of D, d, e, and i in
accordance with the relationship: h = D 2 + d 2 + e + i ##EQU1## h
is therefore between h min = Dmin 2 + dmin 2 + e min + i min = 365
.times. .times. mm ##EQU2## and h max = Dmax 2 + dmax 2 + e max + i
max = 530 .times. .times. mm ##EQU3## for example, in the order of
455 mm.
[0037] The beam 19 connects the longitudinal members 17 and extends
below the floor 31.
[0038] The operating principle of the invention is to optimise the
vertical spatial requirement of the axle 11 by reducing it to the
maximum extent in terms of height in order to free space in order
to lower the floor 31 of the body 20 of the vehicle to the maximum
extent.
[0039] The traditional functions of the axle 11 are separate in
this instance. An axle 11 must generally, on the one hand, connect
the wheels 9 and drive them in terms of rotation by transmitting
the traction and braking torques to them, the wheels 9 thus
rotating together and in parallel and, on the other hand, withstand
the flexion forces which are caused by the mass of the vehicle and
the bodywork 5 and which are transmitted by the suspension system
15.
[0040] The bogie 1 separates the functions of the axle 11 between,
on the one hand, the central shaft 21 which performs the first
function of the axle and, on the other hand, the cross-piece 23
which performs the second function.
[0041] The cross-piece 23 has sufficient inertia to withstand the
flexion brought about by the forces originating from the vehicle
and the bodywork. The cross-piece 23 does not rotate and only the
shaft 21 drives the wheels 9 in terms of rotation.
[0042] The only limitation in terms of the sizing of the central
shaft 21 is thus the function of driving the wheels 9 by the shaft
21 which can therefore have a smaller diameter than if it were
performing the two functions of the axle 11.
[0043] Since the height h of the floor 31 of the body 20 above the
upper edge of the rails 24 is limited by the radius R/2 of the
wheels 9 increased by the radius d/2 of the shaft 21, and by a
minimum spacing i, the invention allows the floor 31 to be lowered
to the height h of 455 mm, further taking into account the
thickness of the floor 31.
[0044] Furthermore, an axle 11 allows a simple transmission system,
the first function of the axle being retained, owing to the central
shaft 21.
[0045] As shown in FIG. 3, in the vehicle 33, a ramp 35 having an
inclination of less than 10% is advantageously provided in order to
connect the floor 31 of the zone above the bogie to a floor zone 39
of lesser height h'. This zone 39 of lesser height h' is, for
example, the access zone for passengers. A relatively low floor
level 39 is therefore achieved for the passenger access zone, in
the order of 355 mm.
[0046] In a variant, each axle comprises two cross-pieces, for
example, when (not illustrated) the bearings are located at the
outer side of the wheels. Each cross-piece connects the two
bearings, the first cross-piece being located in front of the
wheels and the second behind the wheels, symmetrically relative to
the shaft.
[0047] In the embodiment of FIGS. 1 and 2, the cross-piece 23 of
each axle 11 is located below the corresponding shaft 21 with being
spaced therefrom. The shaft 21 is located outside of the
cross-piece 23.
[0048] The embodiment illustrated in FIG. 4, in which the reference
numerals for elements which are similar to those of FIG. 2 have
been retained, differs from that of FIG. 2 in that the cross-piece
23 surrounds the shaft 21. That is to say, the shaft 21 extends
inside the cross-piece 23.
[0049] The cross-piece 23 is nonetheless located at a height lower
than that of the conventional axle for the same application
relative to the peaks of the rails 24. More precisely, the
cross-piece 23 is produced with a neutral surface of the
cross-piece located below the axis of the shaft.
[0050] The surface which is neutral in terms of flexion under a
vertical load of the cross-piece is intended to refer to the
location of the points of zero longitudinal load in terms of
flexion under a vertical load brought about by the bodywork 5 and a
rail vehicle which is supported on the bodywork.
[0051] To this end, the cross-piece 23 has, for example, more
material in the lower portion thereof, between the shaft 21 and the
peak of the rail, than in the upper portion, above the shaft 21. In
the example illustrated, the cross-piece 23 is offset vertically
relative to the shaft 21 so that the clearance Jupper between the
shaft 21 and the upper inner wall of the cross-piece 23 is less
than the clearance Jlower between the shaft 21 and the lower inner
wall of the cross-piece 23.
[0052] The cross-piece 23 defines, with the bearings 22, a sealed
space around the shaft 21 between the bearings 22.
[0053] In this manner, the outputs of the bearings 22 at the inner
side (at the side of each bearing 22 opposite the adjacent wheel
9), are sealed by the cross-piece 23 and it is not necessary to
provide additional sealing means. Only the outputs of the bearings
22 at the outer side must be provided with sealing means. This has
the advantage of simplifying the bearings 22 and reducing the
production cost of the axle 11.
[0054] In this embodiment, the distance i between the shaft 21 and
the floor 31 must be sufficient to accommodate the upper wall of
the cross-piece 23 (which is, for example, in the order of 10 mm)
and provide sufficient clearance Jupper (for example, in the order
of 10 mm). The height of the floor 31 is consequently greater than
the height which can be obtained with the embodiment of FIG. 2 (for
example, greater by approximately 20 mm).
* * * * *