U.S. patent number 3,868,910 [Application Number 05/419,107] was granted by the patent office on 1975-03-04 for railway car suspension motion control system.
This patent grant is currently assigned to Houdaille Industries, Inc.. Invention is credited to John C. Schultz.
United States Patent |
3,868,910 |
Schultz |
March 4, 1975 |
RAILWAY CAR SUSPENSION MOTION CONTROL SYSTEM
Abstract
A filled hydraulic system controls bounce, pitch and roll
vibrational movements of a railroad car by controlling displacement
of hydraulic fluid in and between double-acting single ended piston
hydraulic cylinder units connected between the car body and at
least one truck frame about the center bearing, there being check
valves and a main pressure responsive spool valve in the system, as
well as an accumulator and replenishing reservoir.
Inventors: |
Schultz; John C. (Buffalo,
NY) |
Assignee: |
Houdaille Industries, Inc.
(Buffalo, NY)
|
Family
ID: |
23660813 |
Appl.
No.: |
05/419,107 |
Filed: |
November 26, 1973 |
Current U.S.
Class: |
105/164; 105/210;
105/199.2 |
Current CPC
Class: |
B61F
5/245 (20130101) |
Current International
Class: |
B61F
5/24 (20060101); B61F 5/02 (20060101); B61f
003/08 (); B61f 005/24 (); B61f 005/50 () |
Field of
Search: |
;105/164,199A,210 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Beltran; Howard
Attorney, Agent or Firm: Hill, Gross, Simpson, Van Santen,
Steadman, Chiara & Simpson
Claims
I claim as my invention:
1. A system for controlling operational vibrations of a railroad
car body relative to its suspension, comprising:
double-acting hydraulic fluid displacement units of the rectilinear
piston and cylinder type wherein the piston rod extends from one
end of the piston and the opposite end of the piston is free within
the cylinder and having means for coupling the units to and between
the respective opposite sides of the car body and suspension;
means providing hydraulic displacement connections between said
units;
first valve means in said connections automatically responsive to
hydraulic pressure in said connections as generated by said units
for controlling displacement through the connections and thus
damping relative bounce and pitch motions between the car body and
the suspension;
additional pressure-sensitive valve means in said connections
inactive relative to bounce and pitch but operating automatically
responsive to hydraulic pressure in said connections as generated
by said units to damp roll motion between the car body and
suspension; and
accumulator means in said hydraulic displacement connections to
accomodate piston rod displacement in said units.
2. A system according to claim 1, wherein each cylinder has means
at one end for flexibly connecting it to one of said car body or
suspension and the piston rod extends from the opposite end of the
cylinder and includes means for flexibly connecting it to either
the car body or the suspension alternatively to the cylinder.
3. A system according to claim 1, wherein said hydraulic unit
cylinders have respective working subchambers, said hydraulic
displacement connections comprising respective ducts communicating
with said subchambers and with each other and with said accumulator
means.
4. A system according to claim 3, wherein said first valve means
comprise check valves operating to permit relatively free flow in
one direction between the ducts which are companion to each of the
hydraulic units and resist and damp flow in the opposite direction
between the companion ducts.
5. A system according to claim 4, wherein said pressure-sensitive
valve means comprise a reciprocable spool valve providing
controllable passage means for displacement of fluid between said
ducts and said accumulator means.
6. A system according to claim 5, including ports under the control
of said spool valve and through which ports communication is
effected between said ducts and said accumulator means.
7. A system according to claim 1, wherein said pressure-sensitive
valve means comprise a spool valve and means normally biasing the
spool valve into an inactive position, said spool valve providing
passageways for generally free communication of said hydraulic
connections therethrough with one another and with said accumulator
means in the inactive position of the spool valve, said spool valve
being responsive to roll motion displacement of hydraulic fluid
from said units in opposition to said biasing means to throttle
said passageways and thereby damp said roll motion.
8. A system according to claim 7, wherein said first valve means
comprise check valves cooperating with said spool valve in
effecting roll motion damping.
9. A system according to claim 1, wherein said hydraulic unit
cylinders have respective working subchambers and said hydraulic
displacement connections comprise respective ducts communicating
with said subchambers, and pressure-sensitive valve means
comprising a spool valve reciprocably mounted in a bore and having
fluid displacement grooves therein, said respective ducts having
ports communicating with said bore across said grooves, and said
first valve means cooperating in said ducts with said spool valve
operating in connection with said ports in effecting damping of
roll motion between the car body and suspension.
10. A system according to claim 1, wherein said cylinders have the
piston dividing the cylinder into upper and lower working
subchambers, said connections comprising ducts leading from the
upper subchamber and connected for normally generally free
communication between one another and with said accumulator means
said lower subchambers having ducts in communication therewith,
passage means effecting communication between the upper subchamber
ducts and the lower subchamber ducts, and said first valve means
being in displacement controlling relation to said ducts in said
passage means.
11. A system according to claim 10, wherein said pressure-sensitive
valve means in part provide said passage means and control
displacement between said upper subchamber ducts and also between
said lower subchamber ducts and the upper subchamber ducts.
12. In combination with a railroad car having a body and suspension
means comprising a truck having rail running wheels supporting a
truck frame on which are mounted springs carrying a bolster on
which the body is mounted, a system for controlling operational
vibrations between the car body and the suspension, comprising:
double-acting hydraulic fluid displacement units of the recilinear
piston and cylinder type wherein the piston rod extends from one
end of the piston and the opposite end of the piston is free within
the cylinder and having means coupling the units at respectively
opposite sides of the truck to the truck frame and to the car
body;
means providing hydraulic displacement connections between said
units;
first valve means in said connections automatically responsive to
hydraulic pressure in said connections as generated by said units
for controlling displacement through the connections and thus
damping relative bounce and pitch motions between the car body and
the suspension;
additional pressure-sensitive valve means in said connections
inactive relative to bounce and pitch, but operating automatically
responsive to hydraulic pressure in said connections as generated
by said units to damp roll motion between the car body and
suspension; and
accumulator means in said hydraulic dsiplacement connections to
accommodate piston rod displacement in said units.
13. A combination according to claim 12, wherein each cylinder has
means at one end for flexibly coupling it to one of said car body
or truck frame and the piston rod extends from the opposite end of
the cylinder and includes means for flexibly connecting it to
either the car body or the truck frame alternatively to the
cylinder.
14. A combination according to claim 12, wherein said hydraulic
unit cylinders have respective working subchambers, said hydraulic
displacement connections comprising respective ducts communicating
with said subchambers, the ducts connecting one of the chambers of
the units being normally in free communication with one another
through said accumulator means, and the ducts communicating with
others of the subchambers having communication with the freely
communicating ducts through said valve means.
15. A combination according to claim 14, wherein said first valve
means comprise check valves operating to permit relatively free
flow in one direction between the ducts which are companion to each
of the hydraulic units and resist and damp flow in the opposite
direction between the companion ducts.
16. A combination according to claim 15, wherein said
pressure-sensitive valve means comprises a reciprocable spool valve
providing controllable passage means for displacement of fluid
between said ducts.
17. A combination according to claim 16, including ports under the
control of said spool valve and through which ports communication
is effected between said ducts and said accumulator means.
18. A combination according to claim 12, wherein said
pressure-sensitive valve means comprise a spool valve and means
normally biasing the spool valve into an inactive position, said
spool valve providing passageways for generally free communication
of said hydraulic connections therethrough with one another and
with said accumulator means in the inactive position of the spool
valve, said spool valve being responsive to roll motion
displacement of hydraulic fluid from said units in opposition to
said biasing means to throttle said passageways and thereby damp
said roll motion.
19. A combination according to claim 18, wherein said first valve
means comprise check valves cooperating with said spool valve in
effecting roll motion damping.
20. A combination according to claim 12, wherein hydraulic
cylinders have respective working subchambers and said hydraulic
displacement connections comprise respective ducts communicating
with said subchambers, said pressure-sensitive valve means
comprising a spool valve reciprocably mounted in a bore and having
fluid displacement grooves therein, said respective ducts having
ports communicating with said bore across said grooves, and said
first valve means cooperating in said ducts with said spool valve
operating in connection with said ports in effecting damping of
roll motion between the car body and suspension.
21. A combination according to claim 12, wherein each cylinder has
the piston dividing the cylinder into upper and lower working
subchambers, said connections comprising ducts leading from the
upper subchamber and connected for normally generally free
communication with one another and with said accumulator means,
said lower subchambers having ducts in communication therewith, and
passage means effecting communication between the upper subchamber
ducts and the lower subchamber ducts, and said first valve means
being in displacement controlling relation to said ducts in said
passage means.
22. A combination according to claim 21, wherein said
pressure-sensitive valve means in part provide said passage means
and control displacement between said upper subchamber ducts and
also between said lower subchamber ducts and the upper subchamber
ducts.
Description
This invention relates to the control of motions of railroad cars
related to their suspension systems, and is more particularly
concerned with a new and improved hydraulic system for this
purpose.
Pertinent elements involved in the suspension system of a railroad
car are the car body, bolsters, suspension springs and truck
assemblies. Basically, the car body is supported at its four
corners by springs which rest on the truck frames, this being
generally accomplished through a swivel plate connection between
the car body and each bolster. This constitutes a mass elastic
system. When track irregularities and force and speed disturb the
elastic system at its natural frequency, large undesirable
oscillations of the car body result. In running operation, a car
body basically has three modes of vibration, that is, "bounce"
wherein the entire car body vibrates vertically in phase, "pitch"
wherein the two ends vibrate vertically 180.degree. out of phase,
and "roll" wherein the vibrations are transverse to the length of
the car and are 180.degree. out of phase. Resonant disturbances
which are sustained for any length of time result in a build-up of
car body oscillation amplitudes to undesirable levels. Track
surface irregularities which predominantly produce these
disturbances are variations of the cross level of the tracks and
rail joints. American railroads stagger the joints. Therefore, cars
are subjected to disturbances which contribute to the "roll"
mode.
Conventionally, the railroad car body is supported through center
plates on bolsters, carried on springs on the truck frames riding
on the wheel and axle assembly. During major roll motion the weight
of the car transfers to the side bearing on and between the car and
bolster and the center plate separates. The suspension springs
compress to virtually solid condition on the side toward which the
roll extends and expand on the other side. The wheel opposite the
roll direction lifts from the track. Permitting the roll to build
sufficiently in magnitude may result in extremely high forces being
imposed on the bolster and side frame requiring high endurance
strength in these components. If wheel lift occurs while
negotiating a curve or during a lateral disturbance, derailment may
result.
On bad track, the roll problem occurs in a speed range of about 15
to 30 miles per hour, requiring the engineer to take the train
through this range as rapidly as possible or to slack off and pass
through this speed range where track conditions are more
desirable.
Vertical or bounce frequency is in the order of 2.5 cps and the
roll frequency is in the order of 0.5 cps. Therefore, ordinary
shock absorbers which will sufficiently damp the roll oscillations
are much too stiff for normal vertical or bounce conditions.
An important object of the present invention is to overcome the
foregoing and other disadvantages, deficiencies, inefficiencies,
shortcomings and problems in railroad car suspension systems, and
to attain important advantages and improvements and new and
improved results through the system to be hereinafter described and
which will satisfy the requirements for roll control as well as
providing for efficient bounce and pitch control.
Another object of the present invention is to provide a new and
improved railroad car suspension control system wherein all three
basic modes of vibration are controlled in a simple, efficient and
highly effective manner, wherein vibrations in the roll mode,
especially, are effectively controlled.
A further object of the invention is to provide a new and improved
filled hydraulic system for controlling railroad car suspensions,
and involving an advantageous automatic, self-adjusting valve
arrangement.
Still another object of the invention is to provide a new and
improved control valve arrangement for railroad car suspension
systems.
A still further object of the invention is to provide a new and
improved vibration damping system for railroad cars utilizing
single ended double acting hydraulic control cylinders.
Yet another object of the invention is to provide a new and
improved vibration damping system for railroad cars.
Other objects, features and advantages of the invention will be
readily apparent from the following description of a preferred
embodiment thereof, taken in conjunction with the accompanying
drawing although variations and modifications may be effected
without departing from the spirit and scope of the novel concepts
embodied in the disclosure, and in which:
FIG. 1 is a schematic illustration of the manner in which bounce
and pitch are controlled in a railroad car suspension, according to
the present invention;
FIG. 2 illustrates roll control in the railroad car suspension,
according to the present invention.
As shown in FIGS. 1 and 2, a typical railroad car as exemplified
and which may be a passenger car but may also be a freight car,
includes a body 10 and a suspensison including a pair of trucks 11
(only one of which is shown) on each of which the body is mounted
through the medium of swivel center plate means 12 on a bolster 13
extending transversely under the car. At each opposite end the
bolster 13 is mounted on coil springs 14 supported by truck frame
15 carried by journals extending from the opposite ends of an axle
17 of flanged car wheels 18 riding on rails 19.
According to the present invention, a new and improved control
system for damping bounce, pitch and roll is provided and which is
mounted on and between the car body 10 and the suspension 11.
Either or both of the trucks 11 of the car may be equipped with the
control system. For this purpose, at each side of the truck 11 a
double-acting single ended hydraulic fluid displacement unit 20 is
coupled to and between the body 10 and the truck frame 15 by
suitable flexible joint means 21 such as universal joints to permit
lateral and turning movements between the car body and the truck.
In the present instance, the units 20 comprise rectilinear cylinder
and piston assemblies each comprising a cylinder 22 having an upper
end thereof coupled to the car body 10, and a piston rod 23
extending from the lower end of the cylinder coupled to the truck
frame. If preferred, mounting of the hydraulic units 20 may be
reversed, that is, the piston rod 23 in each instance attached to
the car body and the opposite end of the cylinder 22 attached to
the truck frame 15. In this instance, the hydraulic units 22 are of
the single ended type in which the piston rod 23 extends only
through one end of the cylinder so that a piston 25 fixed on the
piston rod and normally located intermediate the ends of the
working chamber within the cylinder devides the working chamber
within the cylinder into a subchamber 27 at the free end of the
piston and a subchamber 28 on the opposite piston rod side of the
piston. Any suitable means may be provided for filling the
cylinders 22 with suitable oil.
Means providing hydraulic displacement connections between the
units 20 comprise a preferably flexible conduit or duct 31
communicating with the upper working subchamber 27 and a preferably
flexible duct or conduit 32 communicating with the lower subchamber
28. First valve means are provided in the hydraulic displacement
connections automatically responsive to hydraulic pressure in said
connections as generated by said units for controlling displacement
therethrough and thereby damping relative bounce and pitch motions
between the car body and the suspension. Additionally
pressuure-sensitive valve means are provided in the hydraulic
displacement connections inactive relative to bounce and pitch but
operating automatically responsive to hydraulic pressure in said
connections as generated by said units to damp roll motion between
the car body and the suspension. These valve means are desirably
housed within a housing which may be in the form of a block 33 with
which the ducts 31 and 32 communicate.
In a desirable construction, as exemplified in FIG. 1, the valve
means functioning to control and damp relative bounce and pitch
motions comprise a set of check valves for the hydraulic circuit
associated with each of the units 20. Such valves include a check
valve 34 permitting relatively free hydraulic fluid displacement
from the duct 31 to the duct 32 of each of the hydraulic units 20,
and a check valve 35 which is normally biased as by means of a
spring 37 for resisting hydraulic fluid displacement from the duct
32 to the duct 31 of each of the hydraulic units 20. Suitable
means, (not shown) may be provided for adjusting the biasing thrust
of the spring 37 in each instance.
Roll motion damping valve means comprise a reciprocatingly mounted
spool valve member 38 mounted in a bore 39 and normally maintained
centered therein by biasing means such as respective coiled
compression springs 40 thrusting towards the respective opposite
ends of the valve. Each of the ducts 32 communicates with a
respective one end of the bore 39 through a branch 41 through the
associated spring 41 with the adjacent end of the spool valve 38.
Communication between the duct 32 in each instance with its
companion duct 31 is provided for through a branch 42 of the duct
32 opening by way of a port 43 into the bore 39 spaced from the
branch 41 and aligned with that side of an annular groove 44 of the
spool valve 38 which is remote from the adjacent end of the spool
valve, while a port 45 opens into the bore 39 in alignment with the
opposite side of the groove 44 and has a branch passage 47 leading
therefrom to a valve seat 48 for the biased check valve 35. A
branch 49 from the duct branch 47 leads to a valve seat 50 for the
check valve 34 with which the duct 31 communicates by way of a
branch 51.
For pressure release and replenishing of oil, each of the ducts 31
communicates at its end remote from the cylinder 20 through a port
52 with a respective annular passage groove 53 in the spool valve
38 and adjacent to that side of the groove which is remote from the
adjacent groove 44. Intermediate the sides of the grooves 52 a
pressure relief or accumulator and replenishing reservoir 54
communicates by way of respective ducts 55 with the bore 39 for
communication with the ducts 31. Hydraulic fluid filling means 56
may be provided for the reservoir 54.
In operating condition, the hydraulic system as described is
self-contained and is filled with suitable hydraulic fluid such as
oil, and vibration damping in the several modes of capability of
the system. if effected automatically. For example, FIG. 1
demonstrates damping of bounce vibrations wherein the entire car
body vibrates vertically in phase, and pitch vibrations wherein the
two ends of the car vibrate vertically 180.degree. out of phase.
The solid directional arrows represent hydraulic fluid displacement
during compression wherein the distance between the car body 10 and
the truck 11 reduces by yielding of the springs 14 as where the
wheels 18 strike a raised rail joint. Although many prior
suspension systems offer little damping for such vibrational
motions, the present system efficiently damps such motions. During
the compression movement, the upper subchambers 27 of the hydraulic
units 22 contract and the lower subchambers 28 expand. Hydraulic
fluid from the upper chambers 27 displaces through the ducts 31
past the check valves 34 which are raised from their seats 50 as
shown in full outline and the displaced fluid finds its way freely
through the passages 49 bypassing the check valves 35 to the lower
subchambers 28 through the ducts 32. Fluid displaced by the piston
rods 23 is accepted by the reservoir 54 through the ports 52 the
valve grooves 53 and the passageways 55. Any slight rolling
movement is compensated for by stabilizing displacement between the
ends of the ducts 31 through the ports 52, the grooves 53, the
ducts 55 and the reservoir 54. Damping during rebound occurs by
closing of the check valves 34, thereby compelling return flow as
indicated by the dashed arrows in FIG. 1 through the biased check
valves 35. As shown in dash outline in FIG. 1, each check valve 34
during rebound closes against its seat 50 and the check valves 35
are moved by the returning hydraulic fluid from their seats 48
against the bias of the springs 37 which thus restrict return flow
to damp the rebound. Any fluid make up required by the chambers 27
is provided by the reservoir 54. During bounce and pitch damping,
the spool valve 38 remains inactive, serving as a passive flow
passage member in connecting the ducts 31 and 32 with one another
and with the accumulator 54. Inasmuch as hydraulic pressures are
substantially equal at each side of the hydraulic system during
bounce and pitch vibrations, the valve 38 is held inactive even
though the pressure exerted during rebound, especially, may be of
fair magnitude.
During a roll movement as indicated by the directional arrow R in
FIG. 2, the car body 10 tilts either to the left or to the right
relative to the frame 15 of the truck 11, a rightward tilt being
shown by way of example. In this condition, the lower subchamber 28
of the left-hand cylinder 22 and the upper subchamber 27 of the
right-hand cylinder 22 will expel fluid and the opposite
subchambers will expand. The tendency to expel fluid by the lower
left-hand subchamber 28 will be resisted by the check valve 35
connected with the duct 32 from that subchamber and the flow from
the upper right-hand subchamber 27 will displace through its duct
31 past the right-hand check valve 34 with little resistance. This
provides a pressure differential from the left-hand circuit across
the pressure sensitive spool valve 38 shifting it against the
right-hand spring 40 toward the right as shown in FIG. 2. Fluid
displaced by the right-hand piston rod 23 and from the right-hand
circuit end of the spool valve 38 flows to the left-hand circuit
through the ports 52 and the reservoir 54. Shifting of the spool
valve 38 causes it to throttle the right-hand port 52 while the
left-hand port 52 remains open to its duct 31. Thereby, the
reservoir 54 is cut off from the developing high pressure in the
right-hand duct 31. At the same time, the movement of the valve 38
restricts and damps movement of fluid through the right-hand port
43 and the left-hand port 45 by progressively throttling them. This
gradually increases resistance to the roll movement in a smooth
manner as the car body tilt progresses to the point where
right-hand tilt stop bearing 57 on the car body engages tilt stop
bearing 58 on the bolster 13 and the corresponding tilt stop
bearings at the left of the car increase their normal spaced
relation and the center bearing plates 33 may partially separate.
As the rolling motion reaches maximum, the bolster 13 tilts,
compressing the springs 14 at the right side.
It will be understood, of course, that roll toward the left will be
controlled in the same manner as control of roll to the right as
has been described, since the control system is equal and
complementary in each direction.
Not only viscous damping for vertical control, but also viscous
damping for control of roll oscillations is provided by the present
system. In roll oscillation damping, the oscillations will not be
permitted to build up to undesirable amplitudes wherein wheel lift,
derailment or high component loading might occur.
It will be understood that variations and modifications may be
effected without departing from the spirit and scope of the novel
concepts of this invention.
* * * * *