U.S. patent number 3,868,911 [Application Number 05/372,851] 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 |
3,868,911 |
Schultz |
March 4, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
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 hydraulic cylinder
units connected between the car body and at least one truck frame,
there being check valves and a main pressure responsive spool valve
in the system.
Inventors: |
Schultz; John C. (Buffalo,
NY) |
Assignee: |
Houdaille Industries, Inc.
(Buffalo, NY)
|
Family
ID: |
23469880 |
Appl.
No.: |
05/372,851 |
Filed: |
June 22, 1973 |
Current U.S.
Class: |
105/164;
105/199.2; 105/210 |
Current CPC
Class: |
B61F
5/22 (20130101); B61F 5/245 (20130101) |
Current International
Class: |
B61F
5/24 (20060101); B61F 5/02 (20060101); B61F
5/22 (20060101); B61f 003/08 (); B61f 005/24 ();
B61f 005/50 () |
Field of
Search: |
;105/164,182R,210,199A |
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 rail-road
car body relative to its suspension, comprising:
double-acting hydraulic fluid displacement units having means for
coupling them 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
hydrualic pressure in said connections as generated by said units
controlling displacement through the connection and thus damping
relative bounce and pitch motions between the car body and the
suspension; and
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.
2. A system according to claim 1, wherein said actuators comprise
piston and cylinder devices wherein the cylinder has means for
flexibly connecting it to one of said body or suspension and the
piston has a piston rod including 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 units 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, and the
ducts communicating with others of the subchambers having
communication with the freely communicating ducts through said
valve means.
4. 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 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 motiom.
5. A system according to claim 4, wherein said first valve means
comprise check valves cooperating with said spool valve in
effecting roll motion damping.
6. A system according to claim 1, wherein said first valve means
cooperate with said pressure-sensitive valve means in effecting
damping of roll motion between the car body and suspension.
7. A system according to claim 1, wherein said hydraulic units are
linearly acting cylinder and piston devices having 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, 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.
8. A system according to claim 7, wherein said pressure-sensitive
valve means in part provide said passage means and control
displacement between said upper subchamber ducts and between said
lower subchamber ducts and the upper subchamber ducts.
9. 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 having means
coupling them 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
controlling displacement through the connections and thus damping
relative bounce and pitch motions between the car body and the
suspension; and
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.
10. In a combination according to claim 9, wherein said actuators
comprise piston and cylinder devices in which the cylinder has
means for flexibly coupling it to one of said car body or truck
frame and the piston has a piston rod including means for flexibly
connecting it to either the car body or the truck frame
alternatively to the cylinder.
11. In a combination according to claim 9, wherein said hydraulic
units 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,
and the ducts communicating with others of the subchambers having
communication with the freely communicating ducts through said
valve means.
12. In a combination according to claim 9, wherein said
pressure-sensitive valve means comprise a spool valve and means
normally biasing the spool valve into an inactive postion, said
spool valve providing passageways for generally free communication
of said hydraulic connections therethrough 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.
13. In a combination according to claim 12, wherein said first
valve means comprise check valves cooperating with said spool valve
in effecting roll motion damping.
14. In a combination according to claim 9, wherein said first valve
means cooperate with said pressure-sensitive valve means in
effecting damping of roll motion between the car body and
suspension.
15. In a combination according to claim 9, wherein said hydraulic
units are linearly acting cylinder and piston devices having 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, said lower subchambers having
ducts in communication therewith, passage 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.
16. In a combination according to claim 15, wherein said
pressure-sensitive valve means in part provide said passage means
and control displacement between said upper subchamber ducts and
between said lower subchamber ducts and the upper subchamber
ducts.
17. A system for controlling operational vibrations of a railroad
car body relative to its suspension, comprising:
double-acting hydraulic fluid displacement units having means for
coupling them 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 for controlling displacement
therethrough and thus damping relative bounce and pitch motions
between the car body and the suspension;
pressure-sensitive valve means in said connections inactive
relative to bounce and pitch but operating to damp roll motion
between the car body and suspension;
said hydraulic units having respective working subchambers and 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, and the ducts
communicating with others of the subchambers having communication
with the freely communicating ducts through said valve means;
and
said first valve means comprising 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.
18. A system according to claim 17, wherein said pressure-sensitive
valve means comprise a reciprocable spool valve providing
controllable passage means for displacement of fluid between said
ducts.
19. A system according to claim 18, including ports under the
control of said spool valve and through which ports said ducts
communicate.
20. 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 having means
coupling them 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 for controlling displacement
therethrough and thus damping relative bounce and pitch motions
between the car body and the suspension;
pressure-sensitive valve means in said connections inactive
relative to bounce and pitch, but operating to damp roll motion
between the car body and suspension;
said hydraulic units having respective working subchambers and
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, and the ducts
communicating with others of the subchambers having communication
with the freely communicating ducts through said valve means;
and
said first valve means comprising 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.
21. In a combination according to claim 20, wherein said
pressure-sensitive valve means comprise a reciprocable spool valve
providing controllable passage means for displacement of fluid
between said ducts.
22. In a combination according to claim 21, including ports under
the control of said spool valve and through which ports said ducts
communicate.
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 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 about the center bearing
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 nornal 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 suspension,
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.
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
drawings 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 simplified, illustrative fragmentary end elevational
view, partially in section, of a railroad car embodying features of
the present invention.
FIG. 2 is a schematic illustration of the manner in which bounce
and pitch are controlled in the railroad car suspension; and
FIGS. 3,4 and 5 illustrate various progressive phases in roll
control in the railroad car suspension.
Referring, first, to FIG. 1, a typical railroad car is exemplified
which may be a passenger car but in the example shown, comprises a
freight car having a body 10 and suspension including a pair of
trucks 11 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 and having its opposite ends mounted on
coil springs 14 supported by truck frame 15 carried by the journals
extending from the opposite ends of an axle 17 of flanged car
wheels 18 riding on track 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 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 with
a protective flexible boot 24 about the portion of the piston rod
which projects beyond the cylinder. 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. As best seen in FIG. 2,
the hydraulic units 22 are of the double-ended cylinder type,
although single-ended cylinders could be used where rod
displacement is accounted for by design. In the present instance,
the cylinders 22 are such that the piston rod 23 in each instance
extends through the opposite ends of the cylinder and with a piston
25 fixed on the piston rod normally located intermediate the ends
of the working chamber within the cylinder, dividing such working
chamber into an upper subchamber 27 and a lower subchamber 28. On
its upper end, the cylinder 22 has means defining a replenishing
chamber 29 which is partially filled with hydraulic fluid through a
suitable port normally closed by a filler plug 30 positioned so as
to insure the proper air to oil relationship when the unit is in
the installed attitude for servicing purposes. Suitable check
valved replenishing communication between the reservoir 29 and the
working chamber within the cylinder 22 is provided for in any
well-known manner to insure a continously filled operating system
and make up and fluid leakage. Apart from providing replenishing
fluid, the chamber 29 serves as a place for the increased oil
volume in the system which occurs due to thermal expansion. At its
free end portion the piston rod 23 extends into the reservoir
chamber 29 and on moving into the chamber 29, may compress the air
in the chamber.
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 the units 20 for controlling
displacement therethrough and thereby damping relative bounce and
pitch motions between the car body and the suspension. Additonal,
pressure-sensitive valve means are provided in the hydraulic
displacement connections inactive relative to bounce and pitch but
operating automatically responsive to hydraulic pressue in the
connections as generated by the units 20 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. 2, 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 comprises a reciprocating 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, and through the bore with the
companion duct 31 by way of a respective blind end bore 41 in the
adjacent end portion of the valve 38 and one or more side ports 42
near the inner end of the respective bore 41 and a communication
groove 43 in the perimeter of the valve spool registering with a
port 44 from which a branch passage 45 connects with the seat for
the check valve 35 and a branch passage 47 connects with the check
valve 34. Communication between the ducts 31 is effected by way of
adjacently spaced ports 48 near the longitudinal center of the bore
39 and a peripheral groove 49 in the valve 38 bracketing the ports
48.
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 is effected automatically. For example, FIG. 2
demonstrates damping of bounce vibrations wherein the entire 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 hydaulic
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 raise from their seats 50 as shown
in full outline and the displaced fluid finds its way freely
through the passage 47 bypassing the check valve 35 to the lower
subchambers 28 through the ducts 32. Any slight rolling movement is
compensated for by stabilizing displacement between the ends of te
ducts 31 through the ports 48. Damping during rebound occurs by
closing of the check valve 34, thereby compelling return flow as
indicated by the dashed arrows in FIG. 2 through the biased check
valve 35. As shown in dash outline in FIG, 2, the check valve
during rebound closes against its seat 50 and the check valve 35 is
moved by the returning hydraulic fluid from its seat 51 against the
bias of the spring 37 which thus restricts return flow and damps
the rebound. 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. 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
FIGS. 3,4 and 5, 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 FIG. 3, line pressue conditions
at initial roll movement are shown. In this condition, the lower
subchamber 28 of the left-hand cylinder 22 and the uppper
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 te check
valve 35 connected with the duct 32 from that subchamber and the
flow from the upper right-hand subchamber 27 will displalce through
its duct 31 past the right-hand check valve 34 with little
resistance. This provides a pressure differential from the
left-hand circuit toward the right-hand circuit across the pressure
sensitive spool valve 38 tending to shift it toward the right as
shown in FIG. 3, and fluid thus displaced from the right-hand
circuit flows to the left-hand circuit through the ports 48. As
transition to roll mode occurs, as shown in FIG. 4, the
differential pressure across the valve 38 causes it to move against
the bias of right-hand spring 40 and gradually to throttle
communication between the ports 48. At the same time, the valve 38
moves toward restricting movement of fluid thorugh the ports 44.
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 52 on the car body engages tilt stop
bearing 53 on the bolster 13 and the corresponding tilt stop
bearings at the left side of the car increase their normal spaced
relation and the center bearing plates 33 may partially
separate.
As shown in FIG. 5, as the rolling motion reaches maximum, the
bolster 13 tilts, compressing the springs 14 at the right side, and
the pressure differential across the valve 38 reaches maximum
wherein the valve completely shuts off communication between the
ports 48 so that no bypass of fluid can occur therethrough. At this
time the valve 38 also greatly increases the resistance to
displacement of fluid in the hydrualic system by throttling the
ports 44 to minimum flow, thereby thoroughly damping the rolling
motion. By the same token, return to normal attitude will be
resisted until the valve 38 centers.
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.
* * * * *