U.S. patent number 3,628,465 [Application Number 04/790,757] was granted by the patent office on 1971-12-21 for stabilizing high speed railway trucks.
This patent grant is currently assigned to Dominion Foundries and Steel Limited. Invention is credited to Kenneth E. Boyce, Richard N. Dobson, John A. Gaiser, Conrad D. Gris.
United States Patent |
3,628,465 |
Dobson , et al. |
December 21, 1971 |
STABILIZING HIGH SPEED RAILWAY TRUCKS
Abstract
In a railway truck a pivot between the truck frame and the
cooperating bolster is permitted to have lateral displacement to
improve the riding qualities of the truck. The pivot is maintained
automatically centered by motor means which oppose centrifugal
forces that would displace the pivot, e.g., while the truck
traverses a curve, thereby ensuring that lateral displacement is
still possible under such conditions. A special design of such a
truck is provided with a bolster comprising two parts, designated
upper and lower parts, the lower bolster part being pivotally
mounted on the truck transom, while the upper bolster part mounts
the vehicle body for vertical springing movement; the two bolster
parts are connected together by an articulated linkage for lateral
arcuate movement about a longitudinal tilting axis under the action
of motor means.
Inventors: |
Dobson; Richard N. (Burlington,
Ontario, CA), Boyce; Kenneth E. (Hamilton, Ontario,
CA), Gaiser; John A. (Stoney Creek, Ontario,
CA), Gris; Conrad D. (Hamilton, Ontario,
CA) |
Assignee: |
Dominion Foundries and Steel
Limited (Hamilton, Ontario, CA)
|
Family
ID: |
25151661 |
Appl.
No.: |
04/790,757 |
Filed: |
January 13, 1969 |
Current U.S.
Class: |
105/191; 105/164;
105/171; 105/185; 105/193; 105/198.1; 105/199.1; 105/201; 105/210;
105/224.1 |
Current CPC
Class: |
B61F
5/142 (20130101); B61F 5/52 (20130101); B61F
5/22 (20130101); B61F 5/245 (20130101) |
Current International
Class: |
B61F
5/22 (20060101); B61F 5/24 (20060101); B61F
5/14 (20060101); B61F 5/52 (20060101); B61F
5/00 (20060101); B61F 5/02 (20060101); B61f
003/08 (); B61f 005/20 (); B61f 005/24 () |
Field of
Search: |
;105/164,168,197,199,167,185,189,19R,19A,191,193,197R,199R,200,171,197A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: La Point; Arthur L.
Assistant Examiner: Beltran; Howard
Claims
What we claim is:
1. A railway truck comprising a truck frame constituted by
transversely spaced side frames and transom means extending between
the said side frames; at least two wheel and axle assemblies
mounted by the frame and on which the truck runs; a bolster frame
supported on the truck frame; a truck frame pivot member mounted by
the truck frame and engageable with a cooperating bolster frame
pivot member mounted by the bolster frame, the pivot members
cooperating with one another to constrain the bolster frame for
pivoting movement about a generally vertical axis, one of the said
pivot members being mounted by its mounting for lateral movement
relative to its frame; motor means operatively connected between
one of the pivot members and its respective frame and operative to
move the pivot member laterally with respect to its respective
member, detector means operative with the truck upon the presence
of a centrifugal force on the pivot members urging lateral movement
of the pivot axis from a center position, and means operative in
response to said detector means for actuating the motor means to at
least oppose the said force and urge the said pivot axis toward the
said center position.
2. A truck as claimed in claim 1, wherein the said motor means
comprise oppositely operating hydraulic units in operative
engagement between the truck frame and the truck frame pivot
member, means for supplying operating liquid under pressure to the
said hydraulic units, and a reservoir containing operating liquid
and gas connected between each hydraulic unit and the said liquid
supplying means, whereby the gas in the said reservoirs provides
the effect of springs accommodating minor movements of the truck
frame pivot member.
3. A truck as claimed in claim 1, wherein the said motor means
comprise opposed hydraulic units comprising respective cylinder
members each mounted in a respective truck side frame and having
their respective piston members in operative engagement with the
truck frame pivot member.
4. A truck as claimed in claim 3, wherein the said detector means
comprises a movement detector member mounted on the truck frame
operatively connected between the truck frame pivot member and a
truck side frame and providing a corresponding signal upon movement
of the truck frame pivot member from the center position, and the
means responsive to the detector means comprise servo means
receiving the said signal and feeding operating liquid to the said
hydraulic units in response thereto.
5. A truck as claimed in claim 3, wherein the truck frame pivot
member is mounted on the transom means for lateral movement
relative to the truck frame by opposed longitudinally extending
resilient suspension units having their compression axes coincident
and disposed longitudinally of the truck.
Description
FIELD OF THE INVENTION
This invention is concerned with improvements in or relating to
railway trucks, and especially but not exclusively to such trucks
intended for use in high speed passenger cars.
REVIEW OF THE PRIOR ART
It is a continuing requirement for railway vehicles, particularly
passenger cars, to achieve higher speeds combined with a safe,
comfortable ride, and it is now considered a normal requirement for
such cars to travel at speeds as high as 120 m.p.h., speeds in
excess of this figure usually requiring a specially built track
structure. It is of course apparent that faster scheduled train
times can be achieved if the average speed can be maintained as
near as possible to the maximum, even around curves, but attempts
to take present normal passenger cars around curves at these
speeds, even when the track is given the maximum possible banking
elevation, results in uncomfortably high lateral forces (i.e.,
greater than 0.05 g.) being applied to the passengers. Accordingly,
a number of proposals have been made hitherto to tilt the cars
about a longitudinal axis, and thereby reduce the lateral force
applied to passengers.
It is found that careful location of the tilting or roll axis is
required relative to the center of gravity if the maximum effective
banking angles are to be compatible with passenger safety. From
considerations of speed, comfort and safety the center of gravity
is designed to be as low as possible, and desirably the roll axis
should be just below the center of gravity, so that relatively high
tilt angles can be employed in curves, while the resultant of the
centrifugal and gravity forces is still within the middle one third
of the track gauge, which is the generally accepted safety
limit.
It is desirable also to provide as far as possible that the
structure and components used in the trucks are, as much as
possible, the same or very closely similar to those of existing
vehicles, so that the servicing and maintenance thereof can readily
be accomplished with existing railway equipment, shop skills and
personnel.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a new railway
truck having a laterally displaceable pivot between the truck and a
cooperating bolster, and wherein means are provided for maintaining
the pivot centered against the action of centrifugal forces tending
to displace it laterally, for example as the truck traverses a
curve.
In accordance with the invention there is provided a railway truck
comprising a truck frame constituted by transversely spaced side
frames and transom means extending between the said frames; at
least two wheel and axle assemblies mounted by the frame and on
which the truck runs; a bolster frame; a truck frame pivot member
mounted by the truck frame and engageable with a cooperating
bolster frame pivot member mounted by the bolster frame, the pivot
members cooperating with one another to constrain the bolster frame
for pivoting movement about a generally vertical axis, one of the
said pivot members being mounted by its mounting for lateral
movement relative to its frame, motor means operatively connected
between one of the pivot members and its respective frame and
operative to move the pivot member laterally, detector means
operative with the truck upon the presence of a condition applying
a force on the said pivot members urging lateral movement of the
pivot axis from a center position, and means operative in response
to said detector means for actuating the motor means to at least
oppose the said force and urge the said pivot axis toward the said
center position.
DESCRIPTION OF THE DRAWINGS
A particular preferred embodiment will now be described, by way of
example, with reference to the accompanying diagrammatic drawings,
wherein
FIG. 1 is a perspective view with the bolster displaced vertically
from the truck frame for clarity of illustration,
FIG. 2 is a similar view of the bolster with parts thereof broken
away for greater clarity of illustration,
FIG. 3 is a section taken on the line 3--3 of FIG. 1,
FIG. 4 is a view similar to that of FIG. 3, but showing the car
body supported by the truck frame in an inclined attitude, as when
traversing a curve, and
FIG. 5 is a schematic diagram of the control circuit for the
automatically operated bolster centering devices of the
embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The particular preferred embodiment illustrated herein and
modifications thereto are also described and claimed in our
copending application Ser. No. 2796, filed Jan. 14, 1970. The
embodiment comprises a four-wheel, high-speed passenger truck,
having a frame which is a unitary steel casting to provide maximum
rigidity. The frame comprises two parallel side frame members 10
and 11, which have their center portions (10a and 11a respectively)
depressed to the greatest possible extent, these members being
connected to one another intermediate their ends by two
longitudinally spaced transoms 12 and 13. The truck runs on two
similar wheel and axle assemblies, each constituted by a respective
axle 14 and pair of wheels 15. The truck is of course provided with
conventional brakes, but the specific details of the construction
and arrangement thereof will be apparent to those skilled in the
art, and are not further described herein since they form no part
of the present invention. A truck in accordance with the present
invention may also be a motorized unit, in which case each axle
will, for example, be driven by a respective electric motor and
gear unit (not illustrated) mounted on the frame and operatively
connected to the respective axle.
Each axle 14 is rotatably mounted in the frame by a respective pair
of journals 18, each of which in this particular embodiment is
mounted and guided for the necessary generally vertical movement by
two resilient suspension units 19. These suspension units are of
the kind comprising a plurality of flat layers of a suitable
rubber, or a suitable rubber like material, interleaved with flat
metal plates, and provided with metal end plates by which the unit
is connected respectively to the journal and the adjacent side
frames. Such units operate in compression and have a longitudinal
compression axis generally perpendicular to the plane of the said
flat plates; they inherently have the characteristic of a highly
damped spring and are able to accommodate a substantial amount of
movement along their longitudinal axis, while permitting relatively
high shear displacement of their end plates, the shear
characteristic being controllable by control of the compression
along the said axis. The compression axes of the two units 19
supporting each journal 18 are inclined towards each other to
intersect at or close to the normal loaded position of the rolling
axis of the axle.
The car body that is to be mounted on the truck is indicated
diagrammatically herein in FIGS. 3 and 4 as a flat floor member 20,
having two downwardly extending bracket members 21 fastened to the
underside thereof on either side adjacent each truck. Bolster frame
means for mounting the body on the truck frame comprise lower and
upper bolster members 22 and 23 respectively, the lower bolster
member 22 being supported by the side frames and pivotally
connected to the frame between the transoms 12 and 13, while the
upper bolster member 23 is supported by the lower bolster member
and in turn supports the vehicle body 20.
The means supporting the lower bolster member 22 on the truck frame
comprise four resilient suspension units 24, disposed at the four
corners of a rectangle with their longitudinal compression axes
generally vertical, spigots such as 25 on the lower bolster fitting
into the top plate of the respective unit 24. Each suspension unit
24 is mounted between the depressed portion of the respective side
frame and an upwardly curved portion of the bolster member, the
arrangement permitting the use of relatively long units, while
maintaining the lower bolster as low as possible in the truck in
order to maintain the center of gravity of the whole truck as low
as possible. The center portion of the lower bolster is depressed
as much as possible, and is provided with a downwardly extending
spigot 26 that is freely rotatable without play in an aperture 27
in a pivot member 28.
The pivot member 28 is mounted between the two transoms 12 and 13
by two opposed longitudinally spaced resilient suspension units 29,
and also by motor means constituted by two opposed motor units to
be described in detail below, the motor units being connected to
the member 28 via respective suspension members 30. Each unit 29 is
disposed between a flat surface of the respective transom and a
corresponding flat surface of the pivot member 28, with the
longitudinal compression axes thereof coincident and extending
longitudinally of the truck, while each unit 30 extends between a
flat surface of the pivot member and the adjacent end of a piston
31 of a respective motor unit 32 mounted inside the respective
depressed central frame portion.
The upper bolster member 23 has the general form of an open frame,
and in this embodiment comprises two parallel transverse members 33
connected rigidly together by two end members 34 and a central
member 35. The two end members 34 carry respective massive
laterally spaced air springs 36, mounted with their compression
axes vertical, by which the car body 20 is mounted on the bolster,
the springs being supplied in conventional manner with operating
air under pressure from the train air pressure line. The end
portions of the lower bolster member 22 extend upwards into the
respective openings in the upper bolster member, so as to reduce
the overall height of the composite bolster as much as
possible.
Each end of the upper member 23 is connected to the respective end
member 34 of the lower member 22 by an articulated linkage
comprising a generally Y-shaped link member 37, which is operative
as a bellcrank lever and is pivoted to the member 22 about its
crank pivot axis by a pivot rod 38. The end of one crank arm of the
link member 37 is connected by a pivot rod 39 to the adjacent ends
of two spaced parallel links 40, the other ends of the links 40
being connected by a pivot rod 41 to the member 34. The ends of the
other crank arms of the Y link members 37 are connected by pivot
rods 42 to the respective ends of a connecting link 43, which
extends through apertures 44 provided in the member 22, the link 43
being bowed upwards to clear the depressed central portion of the
member 22 over its full range of movement.
The articulated linkage is completed by means of a depending link
45 fixed rigidly at its upper end to the central member 35 and
pivoted at its lower end by a rod 46 to one end of a short
transverse link 47 that is disposed generally parallel to the
connecting link 43 and is accommodated in a recess therein. The
other end of the transverse link 47 is connected to the link 43 by
a pivot rod 48.
The required rolling or tilting motion of the two bolster parts
relative to one another is produced under the control of mechanism
to be described in detail below, this mechanism controlling the
operation of motor means comprising two double-acting hydraulic
units 50, which are disposed one on each side of the bolster. Each
unit 50 comprises a cylinder member 51 pivotally connected at 52 to
the lower bolster member 22 and a piston member 53 pivotally
connected at 54 to the upper member 23. It will be apparent that of
course the connection of the units 50 can be reversed. Diagonally
extending links 55 (FIG. 1) are connected by spherical rubber
bushings to the lower bolster 22 and to brackets 56 fastened to the
car floor approximately in the center thereof, so that they will
not foul the truck side frames as the car body tilts relative
thereto. Laterally extending links 57 (FIGS. 3 and 4) are connected
by similar bushings to the upper bolster member and the brackets 21
of the car floor. These links 55 and 57 ensure that there can be no
substantial transverse and/or longitudinal motion between the
bolster and the car body, and the springs 36 are required to
accommodate only vertical displacement and to provide only vertical
springing.
The action of the connecting linkage can be seen by a comparison of
FIGS. 3 and 4, which show the upper bolster member respectively in
its horizontal position and in one of its extreme tilted positions.
It is important to note that one action of the linkage is to keep
the roll center 58 approximately stationary in the position
illustrated during the bolster tilting, avoiding the large lateral
motions that would be encountered for example with a suspension
comprising two spaced single links. The tilting action illustrated
in FIG. 4 is produced by an increase in length of the motor units
50, forcing the upper bolster member 23 to the left (as seen in the
Figure) relative to the lower member 22. This movement of the upper
member 23 causes a corresponding clockwise movement of the links 37
about the rods 38 via the connection constituted by the end members
34 and the links 40. This lateral movement of bolster member 23
causes a corresponding lateral movement of connecting link 43, via
the links 45 and 47, that applies an additional clockwise rotation
to the bellcrank links 37. In the absence of the links 43, 45 and
47, and their described action on the links 37, the lateral
displacement of the upper bolster member would cause it to tilt
about a laterally moving effective axis disposed approximately
midway between the rods 38, and at the same level as the axes of
these rods (i.e., below the level of the floor 20). The effect of
these additional links is therefore to raise the height of the tilt
axis 58, and by careful choice of the lengths of the individual
links of the articulated linkage it can be located in the desired
position.
In this particular embodiment the immediately adjacent ends of the
two bolster members have the lower bolster member end above the
respective upper bolster member end, so that the upper bolster
member is suspended by the articulated linkage from the lower
bolster member. It is also contemplated that the two bolster
members may be suspended from one another by some other means, the
connecting linkage ensuring that the required relative movement
takes place between them upon operation of the motor units 50.
In a passenger vehicle the preferred height of the axis 58 above
the car floor is such that it is located approximately at the level
of an elbow of the average seated passenger. The actual
determination of the lengths of the links to achieve this result
for a particular truck construction can be effected by one of the
methods known to those skilled in the art, such as a graphical
method.
Referring especially to FIG. 5, each of the motor units 32 is
supplied with an operating liquid under pressure, usually a
suitable oil. This liquid is drawn from a reservoir 60 by a pump 61
and supplied thereby to a pressure reservoir 62, the pump being
controlled in a known manner by means which are now shown to
maintain the liquid in the reservoir 62 between predetermined
pressure limits. Liquid from the reservoir is fed via pipes 63 to
two servo valves 64, which are controlled via pipes 65 from a
hydraulic slave pilot transducer 66. The transducer 66 is in turn
controlled electrically by a master transducer device, indicated
herein as box 67, and to be described in more detail below. The
servo valves 64 feed liquid via respective pipes 68 and
air-containing reservoirs 69 to their respective motor units 32.
While the truck is running straight the servovalves 64 maintain
substantially equal high pressures in their motor units 32,
centering the member 27, the excess oil returning to the reservoir
60 via pipes 70. The usual random track forces applied to the
member 27 are absorbed by the reservoirs 69, the air in these
reservoirs causing them to act as air springs.
As the vehicle traverses a curve corresponding large lateral
centrifugal forces are applied to the lower bolster member, and
thence to the pivot pin 26 and pivot member 27, so that the latter
is urged to move off center. The device 67 feeds a corresponding
control signal to the slave transducer 66 that in turn operates one
or both of the servovalves 64 to effectively increase the pressure
applied to one motor unit and decrease the pressure applied to the
other motor unit, so that a corresponding force is applied to the
member 27 by the units opposing the said centrifugal forces and
urging the member 27 to return to its central position.
Such a control can be arranged to maintain the member 27
substantially central at all times, with the result that the shear
forces applied to the suspension units 24 and 29 are very
considerably reduced, so that more resilient units can be used than
if these units sustained the effect of these lateral forces. Such
more resilient units of course result in a softer and quieter
suspension. In an alternative arrangement the centering of the
member 27 is controlled by a movement detector member 74 mounted on
the pivot member 27 and connected by a link 75 to one of the side
frames. The detector member can operate as described above for the
transducer 67, or may be mechanically connected to a servovalve
such as the valve 64, that is operative under control of the
detector member to supply additional oil under pressure to the
appropriate motor unit cylinder 32 until the pivot block has been
moved back to its center position. Such a centering system operates
completely automatically under control of the detector member and
independently of the tilting control system. In this embodiment the
oil supplied from the pump 61 and reservoir 62 is also fed to the
tilting motor means 50 via connecting pipes 71 and a servovalve
72.
Since the links 55 and 57 between the upper bolster member 23 and
the car body 20 prevent relative lateral and rotational motions
thereof only relative vertical motion need be accommodated by the
main secondary suspension air springs 36. Such springs do not
therefore have to resist and/or accommodate the relatively large
lateral translation motions that would otherwise be applied to them
by a fast moving train. The connection between the upper and lower
bolster members, namely the articulated linkage and the operator
units 50, only permit relative lateral motion thereof under the
control of the units 50, which is in effect a rotational motion
about the center 58. The weight of the car body and of the bolster
is supported from the truck frame by the units 24 which are
designed principally to accommodate the pivoting of the vehicle
body on the truck as it traverses a curve. The wheel primary
suspension units 19 permit vertical translation of the axle 15 and
a limited lateral translation of the wheels relative to the frame,
such as to accommodate the usual irregularities in the track.
It will be seen therefore that the various required springing and
mounting functions are separated out into three distinct groups,
thereby assisting in permitting conventional components to be used.
The first group comprises the upper bolster member 23 and the
associated air springs 36 which provide vertical secondary
springing with no lateral motion. The second group comprises the
mounting of the upper bolster member to the lower bolster member,
whereby the two members function as a single unit between the frame
and the car body for mounting the latter, but are moved relative to
one another to provide the lateral tilting of the car body. The
third group comprises the special pivot suspension which freely
permits the pivoting motion of the bolster relative to the truck
frame, accommodates lateral displacements of the bolster relative
to the truck frame and permits the bolster structure to remain
centered despite high lateral centrifugal forces generated by
deficiencies in the track superelevation.
It will therefore be apparent to those skilled in the art that all
of the parts of the suspension are of relatively conventional
construction and can readily be manufactured and services using
conventional existing equipment, shop skills and personnel.
* * * * *