Note: Descriptions are shown in the official language in which they were submitted.
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1 The present invention relates to a drive system or ships
in icy waters. More particularly, the present invention relates
to a drive system of ships for icy waters, which have a hydro-
dynamic coupling in a shaft line between a prime mover and a
propeller.
Drive systems of the above-mentioned general type are
known in the art. A known drive system includes a prime mover,
a transmission, and a connected shaft line, so that a propeller
can be uncoupled and coupled when the prime mover runs. The in-
troduction of slow running diesel engines in ships for navigationin ice has not been possible. The reason for this is that in
the event of ice contact, there is a danger o an excessive re-
volution pressure resulting from blockiny of the propeller which
can lead to mechanical and thermal overloading of the prime mover~
Drive systems have been proposed which are provided with a reduc-
.ing transmission and have, between the reducing transmission and
the propeller, a hydrodynamic coupling giving ov~rload protec-
tion and acting as a slip clutch, and a rigid bridge coupling, for
example a friction coupling. Both couplings have switching
elements which are independent from one another, and the closed
friction coupling bridges the open slip coupling. Such a con-
struction is disclosed, for example, in the German Ofenlegungs-
schrit 2,106,403. In such a construction, the friction coupling
allows during the slow travelling in icy waters a vibration-ree
torque transmission with smallest possible power losses. Fast
shaft interruptions are possible when the ship contacts ice.
The hydrodynamic coupling which acts in this event can be adjusted,
for example, by an oil pressure device that it prevents overload-
ing of the shat line by automatic emptyin~ o the coupling.
Hydrodynamic couplings for the above-mentioned constructions are
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1 described in the "Zeitschrift MTZ" November 195~, page 388.
The above-described drive units have some disadvantages with
respect to their operation in the specific field and utilization
of diesel engines.
Accordingly, it is an object of the present invention to
provide a drive system of a ship for icy waters, which avoids the
disadvantages of the prior art.
More particularly, it is an object of the present inven-
tion to provide a drive unit of a ship for icy waters, which
better suits to the special requirements of this application
field and advantageously makes possible the utilization of slow
running diesel enqines as prime movers.
In keeping with these objects and with others which will
become apparent hereinafter, one feature~ of the present invention
resides, briefly s~ated,in a drive unit oE a ship for icy waters,
having a prime mover, a propeller, and a shaft line extendin~
therebet~een wherein a 1~wheel element is arranged on a sha~t
line, and a hydrodynamic switch coupling is arranged to couple
the flywheel element with the shaft line.
In accordance with another advantageous feature of the
present invention, the flywheel is formed as a rotation symmet-
rical tubular body and is arranged on the shaft line so that it
concentrically surrounds the shaft line at the respective mounting
location.
Still another feature of the present invention is that
the hydrodynamic switch coupling has a primary wheel which is
seated on the shaft line, and a secondary wheel which forms the
flywheel element or is connected with the flywheel element.
In accordance with a fur-ther advanta~cous featur~ of the
present invention, an auxiliary drive element can be coupled with
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1 the flywheel. A further hydrodynamic coupling can be arranged
to couple the auxiliary drive element with the flywheel.
Finally, the hydrodynamic coupling of the auxiliary
drive can be formed as a hydrodynamic converter.
The novel features which are considered as characteristic
for the invention are set forth in particular in the appended
claims. The invention itself, however, both as to its constructic?
and its method of operation, together with additional objects and
~dvantages thereo~, will be best understood from the following
description of specific embodiments when read in connection with
the accompanying drawings.
FIG. 1 is a view which schematically shows a drive system
of a shaft for navigation in icy waters;
FIG. 2 is an enlarged section of a flywheel element of
the drive of FIG. l; and
FIG. 3 is an enlarged view of the fl~wheel o~ the drive
o~ FIG. 1 with an additional drive elernent.
A drive system or unit o~ a ship for icy waters has a
propeller identified by reference numeral 1, a sha~t line iden-
tified by reference numeral 2 and supported in bearings 3, and
a Diesel engine 4, which drives the shaft line 2 and thereby
the propeller 1. A flywheel element identified by reference
numeral 5 is arranged on the shàft line 2 between the bearings
3.
The flywheel element 5 is shown in detail in FIGS. 2 and
3. The fl~heel element5 is arranged on the shaft line 2 so tha~
it straddles or surrounds the latter and is preferably formed as a
rotation symmetrical tubular body which is concentric with the
shaft line 2. l~he flywheel element or unit has a housing 8 pro-
vided with inlets 6 and an outlet 7. A wor~ing medium is supplied
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1 ~nto the housing 8 of the flywheel element through the inlets6
and discharged from the housing 8 through the outlet 7.
As can be seen from FIG. 2, a double-10w hydrodynamic
coupling 9 is arranged between the flywheel element 5 and the
shaft line 2. The hydrodynamic coupling 9 has a primary double
wheel identified by reference numeral 9', and secondary wheels
identified by reference numeral 9". Both secondary wheels 9"
of the hydrodynamic coupling 9, are fixedly connected with the
flywheel element 5. By actuation of an emptying arrangement
lQ in the condition of blocked working medium supply, uncoupling
between the flywheel 5 and the shaft line 2 takes place.
5traddling support of the flywheel 5 on the shaft line 2 can be
performed with the aid of support bearings which are identified
by reference numeral 11. The shaft line 2 is connected ou-tside
of the housing 8 with the prime mover 4, on the one hand, and
with the propeller 1 via a conneating piece, on the other hand.
When contact with ice is expected, the flywheel 5 can
be driven by filling of the hydrodyanmic coupling 9 so as to at-
tain approxima~ely the number o~ revolutions of the shaft line 2.
Then during the ice contact the properties of the hydrodyanmic
coupling is advantageously utilized~ More particularly, the
coupling transmits, af.ter termination of the acceleration step
with a small slip,only a very small torque.. which substantially
corresponds to the torque generated from the friction of the fly-
wheel in its bearings. On the other hand, the ~orque transmitted
by the coupling with given diameter increases with the increase
of the coupling slip or the difference of the
numbers of revolutions between the primary wheel 9' and the secon-
dary wheel 9" of the coupling g. This means that the smaller is
the number of revolutions of the shaft line during contact of the
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1 propeller wi~h icc or other hindrances, the more active is the
flywheel 5. This leads back to the fact that the primary shaft
of the rotating coupling is suddenly decelerated, so that a great
difference of the numbers of revolution between the secondary
wheel which continues to run because of its flywheel mass and the
primary wheel is controlled. As a result of the great slip,
a higher torque is now transmitted via the hydrodynamic coupling
so that the rotation energy of the coupling secondary wheel and
all flywheel masses connected therewith are transmitted to the
primary wheel in shock-free and wear-free manner. As mentioned
above, the greater is the difference of the numbers of revolution,
the greater is the transmitted torque.
As can be seen from FIG. 3, the drive unit shown here
has a flywheel element which substantially corresponds to
the flywheel ele~nents of FIG. 5. In addition, an auxiliary drive
13 is provided here and connected with the flywheel 5 via a
transmission, such as a reduction transmission 12. A coupliny,
such as advantageously a hydrodynamic coupling 14 is arranged
between the auxiliary drive or drive motor 13 and the transmis-
sion 12. The hydrodynamic coupling 14 is provided for attainingof the above-mentioned advantages. The hydrodynamic coupling 14
may be formed as a double-flow coupling; however, it also may be
formed as a single flow coupling.
When the drive unit is designed in accordance with this
embodiment, the flywheel 5 can be accelerated independently of
the shaft line 2. The flywheel 5 can thereby be driven in rota-
-
tion in the event when the propeller shat line does not rotate.
The rotation energy of the rotating flywheel 5 can be transmitted
by filling of the coupling with the primary wheel on the fly-
wheel 5 to the shaf-t line 2. The acceleration of the flywlleel 5
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1 with the aid of the auxiliary drive 13 can be performed with
any frequency and in any direction and for such a long time until
the eventually blocked propeller is again released.
The additional auxiliary drive can be advantageously
utilized for accelerating reversal maneuvers, wherein the fly-
wheel 5 is driven by the auxiliary drive 13 continuously in a
direction which is opposite to the direction of the propeller
rotation. During the reversal maneuver, the coupling is filled
between the flywheel 5 and the shaft line 2, and the latter is
dragged and accelerated in the opposite direction of rotation.
Instead of the hydrodynamic coupling 14 between the
auxiliary drive 13 and the flywheel 5, a hydrodyanmic torque con-
verter also may be provided.
It will be understood that each of the elements described
above, or two or more together, may also find a useful application
in other types of constructions differing from the types described
above.
While the invention has been illustrated and described
as embodied in a drive system of a ship for icy waters, it is not
intended to be limited to the details shown, since various modi-
fications and structural changes may be made without departing
in any way from the spirit of the present invention.
