U.S. patent application number 09/987890 was filed with the patent office on 2002-05-23 for hydropneumatic suspension unit as well as hydropneumatic suspension system.
This patent application is currently assigned to Knorr-Bremse System fur Schienenfahrzeuge GmbH, a German corporation. Invention is credited to Courth, Christian, Holzl, Stefan, Hommen, Winfried, Kazmeier, Bernd.
Application Number | 20020060384 09/987890 |
Document ID | / |
Family ID | 7663594 |
Filed Date | 2002-05-23 |
United States Patent
Application |
20020060384 |
Kind Code |
A1 |
Kazmeier, Bernd ; et
al. |
May 23, 2002 |
Hydropneumatic suspension unit as well as hydropneumatic suspension
system
Abstract
A hydropneumatic suspension system arranged on a bogie for a
vehicle, particularly for a rail vehicle, and one hydropneumatic
suspension unit respectively which is contained in the suspension
system. For this purpose, the spring accumulator, the reservoir,
the tank and the control unit are arranged in the area of the at
least one spring strut, so that an essentially self-sufficient
suspension unit is obtained. The suspension system may be used and
connected to a levelling unit.
Inventors: |
Kazmeier, Bernd; (Munchen,
DE) ; Courth, Christian; (Munchen, DE) ;
Holzl, Stefan; (Munchen, DE) ; Hommen, Winfried;
(Ebersberg, DE) |
Correspondence
Address: |
Barnes & Thornburg
Ste. 900
750 17th Street, N.W.
Washington
DC
20006
US
|
Assignee: |
Knorr-Bremse System fur
Schienenfahrzeuge GmbH, a German corporation
Munich
DE
|
Family ID: |
7663594 |
Appl. No.: |
09/987890 |
Filed: |
November 16, 2001 |
Current U.S.
Class: |
267/3 ;
267/2 |
Current CPC
Class: |
B61F 5/144 20130101;
B60G 2300/10 20130101; B60G 2202/154 20130101; B60G 2500/203
20130101; B61F 5/22 20130101; B60G 17/056 20130101 |
Class at
Publication: |
267/3 ;
267/2 |
International
Class: |
B61F 005/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 17, 2000 |
DE |
100 56 929.3 |
Claims
1. A hydropneumatic suspension unit for use on a rail vehicle
between a bogie and a car body of the rail vehicle, the unit
comprising: a spring accumulator, a reservoir; at least one spring
strut; a tank; a control unit for controlling the level of the at
least one spring strut; and wherein the spring accumulator, the
reservoir, the tank and the control unit are arranged in the area
of the at least one spring strut.
2. The hydropneumatic suspension unit according to claim 1, wherein
the spring accumulator, the reservoir, the tank and the control
unit are arranged on both sides of a spring strut axis.
3. The hydropneumatic suspension unit according to claim 1, wherein
the spring accumulator, the reservoir, the tank and the control
unit are arranged in a star-shaped manner around the at least one
spring strut.
4. The hydropneumatic suspension unit according to claim 1, wherein
the spring accumulator and the reservoir are connected directly on
the at least one spring strut, while the tank and the control unit
are arranged adjacent thereto on the bogie or on the car body and
are connected by a connection line with the at least one spring
strut.
5. The hydropneumatic suspension unit according to claim 1, wherein
the spring accumulator, the reservoir, the tank and the control
unit are connected directly on the at least one spring strut.
6. A hydropneumatic suspension system for a rail vehicle,
comprising; at least two suspension units according to claim 1,
which are arranged on both sides on the car body of the vehicle;
and a levelling unit coupled with the at least two suspension
units.
7. The hydropneumatic suspension system according to claim 6,
wherein the levelling unit is located separate from the at least
two suspension units on the bogie or on the car body.
8. The hydropneumatic suspension system according to claim 6,
wherein the levelling unit is located with one of the suspension
units.
9. The hydropneumatic suspension system according to claim 6,
wherein the levelling unit is electronically coupled with the at
least two suspension units.
10. The hydropneumatic suspension system according to claim 6,
wherein in that the levelling unit has one differential-pressure
control valve respectively for each suspension unit, and the
differential-pressure control valves are mutually connected by
pressure gauge lines.
11. The hydropneumatic suspension system according to claim 6,
wherein the levelling unit has one differential-pressure control
valve respectively for each suspension unit; the
differential-pressure control valves are connected with the
suspension units by hydraulic lines; and the tanks of the at least
two suspension units are connected with one another by way of a
hydraulic line.
12. The hydropneumatic suspension system according to claim 5,
wherein the levelling unit, for each suspension unit, has one
differential-pressure control valve respectively assigned to the
respective suspension unit, each differential-pressure control
valve is connected by a hydraulic line with a suspension unit on
the other car body side; and the tanks of the at least two
suspension units are connected with one another by a hydraulic
line.
13. A bogie for a rail vehicle including a hydropneumatic
suspension system according to claim 6.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] The invention relates to a hydropneumatic suspension unit
for a vehicle, particularly a rail vehicle. The invention also
relates to a hydropneumatic suspension system which has at least
two suspension units of this type, and to a bogie.
[0002] In such suspension systems, the required hydraulic supply
and control unit is disposed either in or on the bogie of a car
body and is connected with at least one spring strut per body side,
or it is arranged on the car body and supplies the spring struts of
several bogies. In this case, the spring struts of the two car body
sides of a bogie are connected with one another by one overflow
valve respectively. The valve is always closed in normal operation
and opens only when the pressure in one of the two spring struts
drops in an unacceptably excessive manner, for example, as a result
of a line snapping. Thus, it is ensured thereby that the vehicle is
lowered to a defined emergency support without taking up an
inclined position which, as a. rule, does not permit the operation
of the vehicle. This overflow function is normally implemented by a
valve arrangement on the control plate which, however, requires a
high-expenditure tubing of the components of the suspension system
distributed in the bogie or in the car body.
[0003] An example of such a hydropneumatic suspension system is
known from International Patent Document WO 94/08833. The
arrangement illustrated here is used specifically for the level and
inclination control of a car body of a rail vehicle, in which case
the hydropneumatic suspension has to be capable of controlling a
relatively high ratio of the vehicle weights in the fully loaded or
empty condition. In addition, this known construction relates to
the problem that the vehicle level has to be kept at least
approximately constant also during a change of passengers at
stops.
[0004] This system is therefore based particularly on the problem
that the levelling has to be carried out at a high speed; that is,
large amounts of oil can be fed into the hydraulic circuits of the
suspension and can be discharged from them respectively in a
relatively short time. This problem is solved in that, when a
correction requirement is recognized with respect to the level or
inclination of the car body, a pump operates directly against the
pressure of the hydropneumatic spring accumulator of the suspension
damping system and pressure medium will be removed from the
reservoir filled during the travel only when the delivery volume of
the pump is not sufficient for keeping the level of the car body
constant. In particular, as a result, the energy consumption of the
overall system is minimized.
[0005] In order to be able to minimize the size of the units, these
hydropneumatic suspension systems or control circuits exist in the
vehicle several times, in which case each side may comprise only
one or several spring struts. The spring struts of the left and
right suspension are hydraulically connected with one another, so
that one-sided lowerings or lifts of the vehicle can be corrected
by overflowing hydraulic fluid.
[0006] However, such distributed systems for a hydropneumatic
suspension generally require a high-expenditure casing of the
components distributed in the bogie or in the car body. This casing
results in high costs; its laying in the bogie is difficult; and
there is the danger that the hydraulic system of the hydropneumatic
suspension is contaminated by dirt in the lines which may result in
an impairment of its functioning. It is another disadvantage that,
as a result of the unavoidable relative movements between the
individual components on the bogies and the car body as well as
between components at different installation sites on the bogie,
there is the danger of damage to the line elements and a possible
leakage. This may result in a loss of the operability of the entire
system.
[0007] It is therefore an object of the present invention to
further develop a hydropneumatic suspension unit for a vehicle,
particularly a rail vehicle, or a hydropneumatic suspension system
such that the casing expenditures can be reduced.
[0008] This object is achieved by a hydropneumatic suspension unit
of the present invention.
[0009] It was recognized according to the invention that the casing
expenditures can be reduced by a meaningful arrangement of the
parts components in the direct proximity of the spring strut. As a
result, a type of self-sufficient suspension unit can be achieved
which supplies in each case only one or several spring struts on
one side of the car body of the bogie. This leads to a very compact
construction whose components are subjected to essentially no
relative movements with respect to one another. These can therefore
be directly coupled to one another, which significantly simplifies
the construction and reduces the danger of damage as a result of
the dynamic movement of the vehicle when travelling.
[0010] The suspension unit according to the invention is therefore
distinguished by low mounting expenditures and high
reliability.
[0011] As a special embodiment of the suspension unit according to
the invention, the spring accumulator, the reservoir, the tank and
the control unit may be arranged on both sides of a spring strut
axis. This results in a construction which is compact and continues
to be easily accessible with respect to the individual components,
which facilitates the mounting as well as the servicing.
[0012] As an alternative construction, the spring accumulator, the
reservoir, the tank and the control unit may also be arranged in a
star shape around the at least one spring strut, so that all
components are present as closely as possible around the spring
strut axis. This very compact construction can therefore even
better withstand the dynamic stresses occurring during the travel.
In addition, the space requirements for the arrangements can be
minimized thereby.
[0013] As an additional alternative construction of the spring unit
according to the invention, the spring accumulator and the
reservoir can be arranged directly at the at least one spring
strut, while the tank and the control unit are arranged adjacent
thereto at the bogie and are connected by a connection line with
the at least one spring strut. This two-part solution has the
advantage that the spring system can be manipulated better for the
mounting. In addition, the control unit can be mounted at low
expenditures for servicing work, particularly without having to
remove the spring strut.
[0014] According to another aspect of the invention, a
hydropneumatic suspension system is provided, which has at least
two suspension units according to the invention which are arranged
on both sides on the car body of the vehicle, and, in addition,
contains a levelling unit which is assigned to the at least two
suspension units.
[0015] The suspension unit according to the invention thereby also
utilizes the advantage that a casing within the suspension units
will not be necessary. As a result, a very simple modular
construction of the suspension system can be achieved which
significantly simplifies the mounting. As will be explained in
detail in the following, the levelling unit can in this case also
be connected without casing expenditures with the suspension units,
thereby permitting a constructively particularly simple and very
reliable construction.
[0016] Thus, it is, for example, possible that the levelling unit
is arranged separately of the at least two suspension units on the
bogie or on the car body. The levelling unit will then constitute a
separate module which is easy to mount. In addition, the suspension
units may be provided as identically designed modules.
[0017] As an alternative, it is possible to assign the levelling
unit to a suspension unit, whereby the installation expenditures
for the connection lines can be reduced as a whole. Furthermore, no
additional devices are required for the fastening of the levelling
unit on the bogie or on the car body so that the construction is
simplified.
[0018] In this case, the levelling unit can be electronically
coupled with the at least two suspension units. In this manner, an
overflow function can be implemented without any casing
expenditures. Thus, a purely electronic pressure monitoring of the
system pressure can take place in the two levelling circuits. Thus,
when a previously adjusted differential pressure is exceeded, an
electrically actuated drain valve or the like is actuated and thus
provides the required pressure compensation. Such a drain valve can
already be provided in the levelling unit. In addition, for
detecting the pressure in the two suspension units, one electric
pressure sensor respectively can be utilized, for example, for the
electric load detection. This solution requires a pressure
detection of the respective other side by the hydraulic medium
itself, because here only signal cables are required between the
suspension units. This construction can therefore be implemented at
low mounting expenditures and is distinguished by high
reliability.
[0019] As an alternative, it is also possible for the levelling
unit to have one differential-pressure control valve respectively
for each suspension unit, the differential-pressure control valves
being mutually connected by pressure gauge lines. A pressure
compensation is therefore permitted between two or more
self-sufficient suspension units, without the requirement of a
fluid mass flow. In this case, such a differential-pressure control
valve opens up starting from an adjusted differential pressure
between the two suspension units and drains oil from the levelling
circuit into the tank of the respective unit until the differential
pressure has again reached its predetermined amount. In this case,
the oil quantity in each suspension unit does not change, which is
why a tank connection line between the two suspension units is not
required. This results in very low casing expenditures because the
at least two required connection lines between the car sides can be
implemented by the pressure gauge line. These have clearly smaller
dimensions than hydraulic lines and can be laid at lower
expenditures than such hydraulic pipes or hydraulic hoses. In
addition, they have a more flexible design, so that the mounting is
further simplified.
[0020] Furthermore, it is also possible that the levelling unit has
one differential-pressure control valve for each suspension unit,
the differential-pressure control valves being connected with the
suspension units by hydraulic lines, and the tanks of the at least
two suspension units also being connected with one another by a
hydraulic line. Despite the required two hydraulic lines, this
construction is also still distinguished by essentially reduced
casing expenditures in comparison to the prior art because the
casing expenditures are clearly reduced as a whole as a result of
the decentralization of the suspension units.
[0021] According to another embodiment of the invention, it is also
possible that the levelling unit has in each case one
differential-pressure control valve respectively for each
suspension unit. In this case, each differential-pressure control
valve is connected by a hydraulic line with a suspension unit on
the other car body side, and the tanks of the at least two
suspension units are connected with one another also by a hydraulic
line. As a result, the parts components of the system can
essentially be integrated in the suspension units, in which case
they can, in addition, have an essentially identical construction.
The expenditures for providing the suspension system can be
significantly reduced thereby. In addition, clearly lower casing
expenditures can thereby be achieved in comparison to the prior art
because the individual components are combined in suspension
units.
[0022] According to another aspect of the invention, a bogie is
provided which has such a suspension unit or such a suspension
system. Because of the compact construction of the components, the
bogie according to the invention is distinguished by particularly
low mounting expenditures. In addition, it can be provided at
reasonable cost and has a high reliability and service life, in
which case the servicing expenditures can also be minimized.
[0023] Other objects, aspects and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a simplified perspective representation of a bogie
having a hydropneumatic suspension system according to the
invention, individual components being omitted for the purpose of
clarity;
[0025] FIG. 2 is a perspective view of a suspension unit according
to the invention in a first embodiment;
[0026] FIG. 3 is a view of a suspension unit according to the
invention according to a second embodiment;
[0027] FIG. 4 is a schematic operational diagram of a first
embodiment of the suspension system according to the invention;
[0028] FIG. 5 is a schematic operational diagram of a second
embodiment of the suspension system according to the invention;
[0029] FIG. 6 is a schematic operational diagram of a third
embodiment of the suspension system according to the invention;
[0030] FIG. 7 is a schematic operational diagram of a fourth
embodiment of the suspension system according to the invention;
and
[0031] FIG. 8 is a schematic operational diagram of a fifth
embodiment of the suspension system according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] According to the representation in FIG. 1, a suspension
system in this embodiment has two suspension units 2 each mounted
on a frame on a bogie 1 of the vehicle. In this case, the
suspension system is used for damping shocks and vibrations of the
bogie 1 with respect to the car body of the vehicle which is not
shown here and which is arranged above the suspension units 2.
[0033] The active axis of each suspension unit 2 is arranged
perpendicular to the wheel axes of the bogie 1. The two suspension
units 2 jointly support the car body at a line which is not shown
and which connects the upper ends of the suspension units 2 and is
situated parallel to the wheel axes. In this case, the suspension
system is situated essentially in the center between the wheel axes
of the bogie 1. In addition, each suspension unit 2 is arranged
outside the respective wheel disk of the bogie 1, an arrangement in
the wheel disk plane also being possible.
[0034] As illustrated in the detail in FIG. 2, each suspension unit
2 has a carrier or manifold 21 on which a spring strut 22, a spring
accumulator 23, a reservoir 24, a control unit 25 and a tank 26 are
fastened. The control unit 25 has an electric motor 251, an
electronic control module 252 and valve or pressure transducing
units 253. These components are essentially coupled directly to one
another through the carrier or manifold 21 so that no casing
expenditures are required between the latter. For the purpose of
completeness, it should also be pointed out that the suspension
unit 2 also has additional valves, level sensors, a hydraulic pump
etc. as well as a covering, which are not shown here. The level
sensor may be integrated, for example, into the suspension unit 2
or may be mounted externally. As illustrated in FIG. 2, the parts
components of the suspension unit 2 are arranged on both sides of
the spring strut axis.
[0035] FIG. 3 shows a modified construction in which a suspension
unit 2' is essentially divided into two parts units. On the one
hand, the spring strut 22 with the directly flanged-on spring
accumulator 23 and the reservoir 24 form a unit on carrier 21A;
while the control unit 25 and the tank 26 are provided separately
thereof on carrier 21B. A connection line 27 is used as the
connection between carrier 21A and 21B which, however, according to
the representation, may have a very short length because, in
addition, all components are arranged in the area of the spring
strut 22. In this case, the connection line 27 is shown as a
hydraulic hose.
[0036] FIG. 4 is a schematic operational diagram of a first
embodiment of the suspension system according to the invention. In
addition to the two suspension units 2, level sensors 4 assigned to
each suspension 2 and a joint levelling unit 5 are provided. The
level sensors 4 supply corresponding information to the levelling
unit 5 which, in turn, emits a control signal to the control unit
25 of each suspension unit 2. Here, the levelling unit 5 can be
centrally arranged on the bogie 1, on or in the car body or it can
also be assigned to a suspension unit 2. By this construction, an
overflow function can be implemented without any casing
expenditures because a purely electronic pressure monitoring of the
system pressure can take place in the two levelling circuits. In
this case, when a differential pressure, which is preferably
adjusted with respect to the software, is exceeded, an electrically
controlled drain valve is actuated which, as a rule exist for each
unit, whereby the required pressure compensation becomes possible.
For detecting the pressure in the two suspension units 2, one
electric pressure sensor respectively is provided which can be
utilized, for example, also for the electric load detection. Thus,
no pressure detection of the respective other side is required by
way of a hydraulic medium, since in this construction there are
only signal cables between the suspension units. The installation
expenditures for the required signal cables can be further reduced
if the levelling unit 5 is assigned to one of the suspension units
2 or is integrated therein.
[0037] FIG. 5 illustrates second embodiment of the suspension
system according to the invention in which the levelling unit 5 has
two differential-pressure control valves 51 and 52 which are
assigned to the respective suspension units 2. Each
differential-pressure control valve 51 and 52 respectively is
connected with the other suspension unit 2 by a pressure gauge line
or mini gauge line, so that it is provided with the pressure level
of this levelling circuit. Starting from a previously set
differential pressure between the two suspension units 2, the
respective differential-pressure control valve 51 or 52
respectively will open up and will drain oil from the respective
levelling circuit into the tank 26 of the suspension unit 2, until
the differential pressure again falls below the predetermined limit
value. Here, the oil quantity in the suspension system cannot
change. Since only two pressure gauge lines are used for the two
connection lines between the car body sides, casing expenditures
can essentially be avoided. Such pressure gauge lines have
significantly smaller dimensions than hydraulic tube lines or
hydraulic hoses and can be laid in an easier or more flexible
manner. A pressure adjustment is by an offset signal which is
transmitted by an upright oil pressure column, which is closed in
itself, in a pressure gauge line from one differential-pressure
sensor to another differential-pressure sensor of the differential
pressure control valves. Thus, no pressure compensation takes place
by a fluid mass flow.
[0038] FIG. 6 illustrates a third embodiment of the suspension
system according to the invention, here the two
differential-pressure control valves 51 and 52 being arranged as a
separate unit on the bogie 1 or on the car body. In addition, this
construction has one hydraulic line respectively from the levelling
unit 5 to the suspension units 2. Another hydraulic line connects
the tanks 26 of the suspension units 2 with one another in order to
prevent an unacceptably high amount of oil on one car body side in
the event of an overflow of oil.
[0039] According to FIG. 7, the differential-pressure control
valves 51 and 52 in a fourth embodiment can also be assigned to a
suspension unit 2, so that they are not present as a separate
module.
[0040] In a fifth embodiment of the present invention according to
FIG. 8, the differential pressure control valves 51 and 52 may also
each be assigned to the suspension units 2. An additional hydraulic
line will then be required in order to form the levelling
circuit.
[0041] In addition to the embodiments indicated here, the invention
permits additional design principles.
[0042] Thus, some of the components of the electric control unit 25
or additional electric components may be arranged on the bogie 1 or
on the car body, the control unit 25 interacting with these
components. As a result, the stress on one portion of the electric
components can be reduced within certain limits.
[0043] In addition, it is possible to arrange the spring
accumulator 23, the reservoir 24, the tank 26 and the control unit
25 in a star-shaped manner around the respective spring strut
22.
[0044] Also, when larger loads are to be absorbed, two or several
spring struts 22 can be arranged directly side-by-side, which are
then supplied or controlled by a common spring accumulator 23,
reservoir 24, tank 26 or a joint control unit 25. Furthermore,
spring struts 22 which are arranged on one side of the vehicle in a
mutually spaced manner can also be serviced by joint supply and
control components.
[0045] When the levelling unit 5 is arranged on the car body or on
the bogie 1, it can also control more than two suspension units 2
arranged laterally on the vehicle.
[0046] The invention thus provides a hydropneumatic suspension
system for a vehicle, particularly for a rail vehicle, and a
hydropneumatic suspension unit respectively which is contained in
the suspension system, and by means of which the casing
expenditures for the suspension system can clearly be reduced. As a
result, the mounting and the maintenance of the system can be
significantly simplified.
[0047] Although the present invention has been described and
illustrated in detail, it is to be clearly understood that the same
is by way of illustration and example only, and is not to be taken
by way of limitation. The spirit and scope of the present invention
are to be limited only by the terms of the appended claims.
* * * * *