U.S. patent application number 14/325411 was filed with the patent office on 2015-01-15 for ship's propulsion unit.
This patent application is currently assigned to ABB OY. The applicant listed for this patent is ABB OY. Invention is credited to Petri SAKKINEN.
Application Number | 20150017032 14/325411 |
Document ID | / |
Family ID | 48747994 |
Filed Date | 2015-01-15 |
United States Patent
Application |
20150017032 |
Kind Code |
A1 |
SAKKINEN; Petri |
January 15, 2015 |
SHIP'S PROPULSION UNIT
Abstract
The present disclosure relates to a ship's propulsion unit which
includes: a closed liquid cooling system having an inner space
containing liquid. The inner space is partly limited by a
cylindrical outer surface of a cylindrical section of a motor
housing section of the propulsion unit for exchanging thermal
energy between an electric motor arranged in the cylindrical
section of the motor housing section and liquid in the inner space.
The inner space of the closed liquid cooling system is partly
limited by the shell structure of the propulsion unit so that
liquid in the inner space is in direct contact with the shell
structure of the propulsion unit for exchanging thermal energy
between liquid in the inner space and water surrounding the
propulsion unit via the shell structure of the propulsion unit.
Inventors: |
SAKKINEN; Petri; (Helsinki,
FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ABB OY |
Helsinki |
|
FI |
|
|
Assignee: |
ABB OY
Helsinki
FI
|
Family ID: |
48747994 |
Appl. No.: |
14/325411 |
Filed: |
July 8, 2014 |
Current U.S.
Class: |
417/423.8 |
Current CPC
Class: |
B63H 21/17 20130101;
B63J 2/12 20130101; H02K 7/14 20130101; B63H 5/125 20130101; B63H
23/24 20130101; B63H 21/30 20130101; F01P 3/202 20130101; B63H
2005/1258 20130101; H02K 9/19 20130101; B63H 21/383 20130101 |
Class at
Publication: |
417/423.8 |
International
Class: |
F01P 3/20 20060101
F01P003/20; B63H 21/17 20060101 B63H021/17; B63H 21/30 20060101
B63H021/30 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2013 |
EP |
13175688.4 |
Claims
1. A ship's propulsion unit, comprising: a shell structure
configured to be arranged below a hull of the ship and immersible
at least partly in water so that the shell structure will be at
least partly surrounded by water; an electric motor for rotating a
propeller outside the shell structure, the electric motor having a
stator and a rotor for rotating in the stator; wherein the electric
motor is arranged in a motor housing section of the shell structure
so that the stator of the electric motor is form-fitted into a
cylindrical section of the motor housing section of the shell
structure; the cylindrical section having a cylindrical outer
surface; and wherein the shell structure includes a support section
having a lower end connected to the motor housing section of the
shell structure and an upper end connected to the hull of the ship;
a closed liquid cooling system having an inner space containing
liquid, the inner space of the closed liquid cooling system being
partly limited by the cylindrical outer surface of the cylindrical
section of the motor housing section so that liquid in the inner
space of the closed liquid cooling system will be in direct contact
with the cylindrical outer surface of the cylindrical section of
the motor housing section for exchanging thermal energy between the
electric motor arranged in the cylindrical section of the motor
housing section and liquid in the inner space of the closed liquid
cooling system via the cylindrical section of the motor housing
section; and the inner space of the closed liquid cooling system
being partly limited by the shell structure of the propulsion unit
so that liquid in the inner space of the closed liquid cooling
system will be in direct contact with the shell structure of the
propulsion unit for exchanging thermal energy between liquid in the
inner space of the closed liquid cooling system and water
surrounding the propulsion unit via the shell structure of the
propulsion unit.
2. The propulsion unit according to claim 1, wherein the closed
liquid cooling system is a closed liquid tank forming said inner
space containing liquid, the inner space of the closed liquid tank
being partly limited by a part of the cylindrical outer surface of
the cylindrical section of the motor housing section so that liquid
in the inner space of the closed liquid tank will be in direct
contact with said part the cylindrical outer surface of the
cylindrical section of the motor housing section for exchanging
thermal energy between the electric motor arranged in the
cylindrical section of the motor housing section and liquid in the
inner space of the closed liquid tank via said part of the
cylindrical section of the motor housing section between the
electric motor and liquid in the inner space of the closed liquid
tank; and the inner space of the closed liquid tank being partly
limited by the shell structure of the propulsion unit so that
liquid in the inner space of the closed liquid tank will be in
direct contact with the shell structure for exchanging thermal
energy between liquid in the inner space of the closed liquid tank
and water surrounding the shell structure via the shell
structure.
3. The propulsion unit according to claim 1, wherein the closed
liquid cooling system is a closed liquid circulation cooling system
having said inner space containing liquid and provided with liquid
circulation means for circulating liquid in the inner space of the
closed liquid circulation cooling system, the inner space of the
closed liquid circulation cooling system being partly limited by a
part of the cylindrical outer surface of the cylindrical section of
the motor housing section so that liquid which flows in the inner
space of the closed liquid circulation cooling system will be in
direct contact with said part of the cylindrical outer surface of
the cylindrical section of the motor housing section for exchanging
thermal energy between the electric motor arranged in the
cylindrical section of the motor housing section and liquid which
flows in the inner space of the closed liquid circulation cooling
system via said part of the cylindrical section of the motor
housing section between the electric motor and liquid circulating
in the inner space of the closed liquid circulation cooling system;
and the inner space of the closed liquid circulation cooling system
being additionally partly limited by the support section of the
shell structure of the propulsion unit so that liquid which flows
in the inner space of the closed liquid circulation cooling system
will be in direct contact with the support section of the shell
structure for exchanging thermal energy between liquid which flows
in the inner space of the closed liquid circulation cooling system
and water surrounding the support section of the shell structure
via the support section of the shell structure.
4. The propulsion unit according to claim 3, wherein said part of
the cylindrical outer surface of the cylindrical section of the
motor housing section in contact with liquid in the inner space of
the closed liquid circulation cooling system is provided with
partition elements for creating several individual flows of liquid
along said part of the cylindrical outer surface of the cylindrical
section of the motor housing section.
5. The propulsion unit according to claim 3, wherein the closed
liquid circulation cooling system is provided with a first liquid
tank at a point of the closed liquid circulation cooling system
where the inner space of the closed liquid circulation cooling
system is partly limited by said part of the cylindrical outer
surface of the cylindrical section of the motor housing section,
the first liquid tank having a first inner space that forms a part
of the inner space of the closed liquid circulation cooling system;
the first liquid tank being in fluid communication with the closed
liquid circulation cooling system such that liquid which flows in
the closed liquid circulation cooling system will flow through the
first inner space of the first liquid tank; and the first inner
space of the first liquid tank being partly limited by said part of
the cylindrical outer surface of the cylindrical section of the
motor housing section so that liquid in a first inner space of the
first liquid tank will be in direct contact with the cylindrical
outer surface of the cylindrical section of the motor housing
section for exchanging thermal energy between the electric motor
arranged in the motor housing section and liquid which flows in the
first inner space of the first liquid tank via said part of the
cylindrical outer surface of the cylindrical section of the motor
housing section.
6. The propulsion unit according to claim 5, wherein the first
liquid tank is additionally partly limited by the support structure
of the shell structure so that liquid in the first inner space of
the first liquid tank will be additionally in direct contact with
the support structure of the shell structure for exchanging thermal
energy between liquid which flows in the first inner space of the
first liquid tank of the closed liquid circulation cooling system
and water surrounding the support structure of the shell structure
via the support structure of the shell structure.
7. The propulsion unit according to claim 3, wherein the closed
liquid circulation cooling system is provided with a second liquid
tank at a point of the closed liquid circulation cooling system
where the closed liquid circulation cooling system is partly
limited by the support section of the shell structure so that the
second liquid tank is partly limited by the support section of the
shell structure, the second liquid tank having a second inner space
that forms a part of the inner space of the closed liquid
circulation cooling system; the second liquid tank being in fluid
communication with the closed liquid circulation cooling system
such that liquid which flows in the closed liquid circulation
cooling system will flow through the second inner space of the
second liquid tank; and the second liquid tank being partly limited
by the support section of the shell structure so that liquid in the
second inner space of the second liquid tank will be in direct
contact with the support section of the shell structure for
exchanging thermal energy between liquid which flows in the second
inner space of the second liquid tank and water surrounding the
support section of the shell structure via the support section of
the shell structure.
8. The propulsion unit according to claim 3, wherein the support
section of the shell structure is provided with a cavity in fluid
communication with water surrounding the shell structure for
allowing water surrounding the shell structure to enter the cavity
and to exit the cavity; the closed liquid circulation cooling
system comprising a tube section; the inner space of the closed
liquid circulation cooling system being partly limited by the tube
section; and the tube section being arranged in the cavity so that
an outer surface of the tube section will be in the cavity in
direct contact with water surrounding the shell structure.
9. The propulsion unit according to claim 8, wherein the tube
section is a part of a liquid-liquid-heat exchanger for exchanging
thermal energy between liquid in the inner space of the closed
liquid circulation cooling system and water surrounding the shell
structure; and said liquid-liquid-heat exchanger is arranged in the
cavity.
10. The propulsion unit according to claim 8, wherein the cavity is
at least partly closed by at least one cover forming a part of the
shell structure.
11. The propulsion unit according to claim 1, wherein the lower end
of the support section of the shell structure is connected to the
motor housing section of the shell structure so that the
cylindrical outer surface of the cylindrical section of the motor
housing section of the shell structure of the propulsion unit
partly forms the outermost surface of the propulsion unit.
12. The propulsion unit according to claim 11, wherein the part of
the cylindrical outer surface of the cylindrical section of the
motor housing section forming the outermost surface of the
propulsion unit is provided with projecting heat-exchanging
elements for enhancing transfer of thermal energy between the
electric motor in the motor housing section and water surrounding
the part of the cylindrical outer surface of the cylindrical
section of the motor housing section forming the outermost surface
of the propulsion unit.
13. The propulsion unit according to claim 1, wherein by the
cylindrical section of the motor housing section is of a
single-layer construction
14. The propulsion unit according to claim 1, wherein the part of
the cylindrical section of the cylindrical outer surface of the
motor housing section in contact with liquid in the closed liquid
cooling system is provided with projecting heat-exchanging elements
for enhancing transfer of thermal energy between the electric motor
in the motor housing section and liquid in the closed liquid
cooling system.
15. The propulsion unit according to claim 1, wherein the closed
liquid cooling system is arranged fully enclosed by the shell
structure of the propulsion unit.
16. The propulsion unit according to claim 1, wherein the electric
motor is a permanent-magnet electric motor.
17. The propulsion unit according to claim 4, wherein the closed
liquid circulation cooling system is provided with a first liquid
tank at a point of the closed liquid circulation cooling system
where the inner space of the closed liquid circulation cooling
system is partly limited by said part of the cylindrical outer
surface of the cylindrical section of the motor housing section,
the first liquid tank having a first inner space that forms a part
of the inner space of the closed liquid circulation cooling system;
the first liquid tank being in fluid communication with the closed
liquid circulation cooling system such that liquid which flows in
the closed liquid circulation cooling system will flow through the
first inner space of the first liquid tank; and the first inner
space of the first liquid tank being partly limited by said part of
the cylindrical outer surface of the cylindrical section of the
motor housing section so that liquid in a first inner space of the
first liquid tank will be in direct contact with the cylindrical
outer surface of the cylindrical section of the motor housing
section for exchanging thermal energy between the electric motor
arranged in the motor housing section and liquid which flows in the
first inner space of the first liquid tank via said part of the
cylindrical outer surface of the cylindrical section of the motor
housing section.
18. The propulsion unit according to claim 4, wherein the closed
liquid circulation cooling system is provided with a second liquid
tank at a point of the closed liquid circulation cooling system
where the closed liquid circulation cooling system is partly
limited by the support section of the shell structure so that the
second liquid tank is partly limited by the support section of the
shell structure, the second liquid tank having a second inner space
that forms a part of the inner space of the closed liquid
circulation cooling system; the second liquid tank being in fluid
communication with the closed liquid circulation cooling system
such that liquid which flows in the closed liquid circulation
cooling system will flow through the second inner space of the
second liquid tank; and the second liquid tank being partly limited
by the support section of the shell structure so that liquid in the
second inner space of the second liquid tank will be in direct
contact with the support section of the shell structure for
exchanging thermal energy between liquid which flows in the second
inner space of the second liquid tank and water surrounding the
support section of the shell structure via the support section of
the shell structure.
19. The propulsion unit according to claim 4, wherein the support
section of the shell structure is provided with a cavity in fluid
communication with water surrounding the shell structure for
allowing water surrounding the shell structure to enter the cavity
and to exit the cavity; the closed liquid circulation cooling
system comprising a tube section; the inner space of the closed
liquid circulation cooling system being partly limited by the tube
section; and the tube section being arranged in the cavity so that
an outer surface of the tube section will be in the cavity in
direct contact with water surrounding the shell structure.
20. The propulsion unit according to claim 9, wherein the cavity is
at least partly closed by at least one cover forming a part of the
shell structure.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a ship's propulsion unit as defined
in the preamble of independent claim 1.
[0002] The invention relates to ship's propulsion units such as
azimuthing propulsion units as presented in U.S. Pat. No.
5,403,216.
[0003] U.S. Pat. No. 6,312,298 B1 presents in an electromotive
drive system in an improved form of a propeller motor for a ship,
the cooling of the motor in a simple manner is provided. For
re-cooling a circulating coolant, an annular duct is provided,
which is arranged inside a shaft-like supporting part on its wall.
With the assistance of this supporting part, the propeller motor is
arranged, gondola-like, on the lower side of the ship.
[0004] U.S. Pat. No. 6,485,339 B1 presents an electric propulsion
pod for a ship having an electric propulsion pod heat rejection
member. The electric propulsion pod is attached below the ship by a
hollow ship access shaft. The electric propulsion pod contains an
electric motor for producing a water propulsion. The electric motor
generates an amount of heat that is conducted and subsequently
released into the water through the electric propulsion pod and
ship access shaft surfaces. The heat rejection member is fitted for
increasing the conduction and subsequent release of the electric
motor heat.
[0005] U.S. Pat. No. 7,186,156 B1 presents propulsion unit for
propelling a waterborne vessel includes an electric motor arranged
to provide propulsion, and a housing arranged to contain the motor.
The interior of the housing is maintained at an increased pressure
of above roughly 2 bar to increase the cooling effect of a cooling
gas maintained therein. An end region of the housing is provided
with a heat exchange mechanism arranged to cool a cooling gas
passing thereover. The heat exchange mechanism is associated with
the housing such that, in use, water surrounding the housing
absorbs heat therefrom.
[0006] WO0154973 a propulsion unit arrangement for a ship. The
arrangement includes a motor unit comprising a motor housing which
is arranged in the water and which comprises a motor and any
control means related thereto, as well as a propeller which is
arranged at a motor shaft. Said motor unit comprises an electrical
motor for which the cooling is arranged to take place via the
surface of the motor's whole circumference through the motor's
casing structure directly into the water which surrounds said
unit.
Objective of the Invention
[0007] The object of the invention is to provide an efficient
cooling of a ship's propulsion unit.
Short Description of the Invention
[0008] The ship's propulsion unit of the invention is characterized
by the definitions of independent claim 1.
[0009] Preferred embodiments of the ship's propulsion unit are
defined in the dependent claims.
[0010] "Closed" in means in this connection for example that water
surrounding the propulsion unit, when the propulsion unit is at
least partly immersed in water, is not let into the closed liquid
cooling system, nor is liquid discharged from the closed liquid
cooling system into water surrounding the propulsion unit, when the
propulsion unit is at least partly immersed in water.
[0011] Cooling of the motor's whole circumference through the
motor's casing structure is a very effective way to cool the stator
of the electric motor. However, it is difficult to arrange strength
wise optimum design for motor housing section connection to the
supporting section if the top part of the motor housing section
cannot be used for this purpose. Strength wise optimal design for
motor housing connection to the support section would be such that
supporting section would be connected rigidly to the entire length
of the motor housing section. This can be arranged if supporting
part is welded directly to top of motor housing section. However,
in this case water cannot flush the whole circumference of motor
housing section and cooling of electrical motor is reduced
resulting hot spot to top of the motor housing section.
[0012] This problem can for example be solved by providing the
support section with a closed liquid cooling system in the form of
a closed liquid tank filled with liquid that is in contact with the
top part of motor housing section as is the case in the first
embodiment. Alternatively or additionally, this problem can be
solved by using a closed liquid circulation cooling system that is
filled with cooling liquid that flows in contact with the top part
of motor housing section as is the case in the second, third,
fourth, fifth and sixth embodiment. This arrangement is strength
wise superior when compared to other arrangements with an opening
above the motor housing section or with an opening between the
motor housing section and the support section. This design can
provide for smaller outer dimensions and weight of the final
propulsion unit due to strength wise optimized design.
LIST OF FIGURES
[0013] In the following the invention will described in more detail
by referring to the figures, of which
[0014] FIG. 1 shows a propulsion unit arrangement according to a
first embodiment,
[0015] FIG. 2 shows the working principle of the propulsion unit
arrangement shown in FIG. 1,
[0016] FIGS. 3 to 5 shows some alternative configurations of
section X-X in FIGS. 1 and 2,
[0017] FIG. 6 shows a propulsion unit arrangement according to a
second embodiment,
[0018] FIG. 7 shows the working principle of the propulsion unit
arrangement shown in FIG. 6,
[0019] FIGS. 8 to 11 shows some alternative configurations of
section X-X in FIGS. 6 and 7,
[0020] FIG. 12 shows a propulsion unit arrangement according to a
third embodiment,
[0021] FIG. 13 shows the working principle of the propulsion unit
arrangement shown in FIG. 12,
[0022] FIGS. 14 to 17 shows some alternative configurations of
section X-X in FIGS. 12 and 13,
[0023] FIG. 18 shows a propulsion unit arrangement according to a
fourth embodiment,
[0024] FIG. 19 shows the working principle of the propulsion unit
arrangement shown in FIG. 18,
[0025] FIGS. 20 to 23 shows some alternative configurations of
section X-X in FIGS. 18 and 19,
[0026] FIG. 24 shows a propulsion unit arrangement according to a
fifth embodiment,
[0027] FIG. 25 shows the working principle of the propulsion unit
arrangement shown in FIG. 24,
[0028] FIGS. 26 to 29 shows some alternative configurations of
section X-X in FIGS. 24 and 25,
[0029] FIG. 30 shows a propulsion unit arrangement according to a
sixth embodiment,
[0030] FIG. 31 shows the working principle of the propulsion unit
arrangement shown in FIG. 30,
[0031] FIG. 32 is a side view of the propulsion unit arrangement
shown in FIG. 30,
[0032] FIGS. 33 to 36 show some alternative configurations of
section X-X in FIGS. 30 and 31.
DETAILED DESCRIPTION OF THE INVENTION
[0033] In the following the ship's propulsion unit and some
preferred embodiments and variants of the ship's propulsion unit
will be described in greater detail.
[0034] The propulsion unit (not marked with a reference numeral)
comprises a shell structure 1 arranged below a hull 2 of the ship
(not marked with a reference numeral) and immersible at least
partly in water (not marked with a reference numeral) so that the
shell structure 1 is at least partly surrounded by water.
[0035] The propulsion unit comprises an electric motor 3 for
rotating a propeller 23 outside the shell structure 1. The electric
motor 3 has a stator 4 and a rotor 5 for rotating in the stator 4.
In the figures a propeller shaft 24 is connected to the rotor 5 for
rotating with the rotor 5 as the rotor 5 rotates in the stator 4.
In the figures the propeller shaft 24 is rotatable arranged in the
shell structure by means of bearing arrangements 25. In the figures
the propeller 23 is attached to the propeller shaft 24
[0036] The electric motor 3 is arranged in a motor housing section
6 of the shell structure 1 so that the stator 4 of the electric
motor 3 is form-fitted into a cylindrical section 7 of the motor
housing section 6 of the shell structure 1.
[0037] The cylindrical section 7 has a cylindrical outer surface
8.
[0038] The shell structure 1 includes a support section 26 having a
lower end connected to the motor housing section 6 of the shell
structure 1 and an upper end connected to the hull 2 of the ship.
The upper end of the support section 26 may be connected to the
hull 2 of the ship by means of a turning arrangement (not shown in
the drawings) for turning the propulsion unit with respect to the
hull 2 of the ship.
[0039] The propulsion unit comprises a closed liquid cooling system
9 having an inner space 10 containing liquid 11.
[0040] The inner space 10 of the closed liquid cooling system 9 is
partly limited by the cylindrical outer surface 8 of the
cylindrical section 7 of the motor housing section 6 so that liquid
11 in the closed liquid cooling system 9 is in direct contact with
the cylindrical outer surface 8 of the cylindrical section 7 of the
motor housing section 6 for exchanging thermal energy between the
electric motor 3 arranged in the cylindrical section 7 of the motor
housing section 6 and liquid in the inner space 10 of the closed
liquid cooling system 9 via the cylindrical outer wall 7 of the
motor housing section 6 of the shell structure 1 of the propulsion
unit.
[0041] The inner space 10 of the closed liquid cooling system 9 is
additionally partly limited by the shell structure 1 of the
propulsion unit so that liquid in the inner space 10 of the closed
liquid cooling system 9 is in direct contact with the shell
structure 1 of the propulsion unit for exchanging thermal energy
between liquid in the inner space 10 of the closed liquid cooling
system 9 and water surrounding the propulsion unit via the shell
structure 1 of the propulsion unit.
[0042] The closed liquid cooling system 9 may be in the form of a
closed liquid tank 12 forming said inner space 10 containing
liquid, as in the first embodiment of the propulsion unit shown in
FIGS. 1 to 5.
[0043] In a such embodiments of the propulsion unit the inner space
10 the closed liquid tank 12 is partly limited by a part 13 of the
cylindrical outer surface 8 of the cylindrical section 7 of the
motor housing section 6 so that liquid in the inner space 10 of the
closed liquid tank is in direct contact with said part the
cylindrical outer surface 8 of the cylindrical section 7 of the
motor housing section 6 for exchanging thermal energy between the
electric motor 3 arranged in the cylindrical section 7 of the motor
housing section 6 and liquid in the inner space 10 of the closed
liquid tank 12 via said part 13 the cylindrical section 7 of the
motor housing section 6 between the electric motor 3 and liquid 11
in the closed liquid tank 12.
[0044] In a such embodiments of the propulsion unit the inner space
10 of the closed liquid tank 12 is additionally partly limited by
the shell structure 1 of the propulsion unit so that liquid in the
inner space 10 of the closed liquid tank 12 is in direct contact
with the shell structure 1 for exchanging thermal energy between
liquid in the inner space 10 of the closed liquid tank 12 and water
surrounding the propulsion unit via the shell structure 1.
[0045] The closed liquid tank 12 may be provided with circulation
means (not shown in the figures) for circulating liquid in the
closed liquid tank.
[0046] The inner space 10 of the closed liquid tank 12 may be
provided with baffles (not shown in the figures) for serving as
heat exchanging elements between liquid in the inner space 10 of
the closed liquid tank 12 and the support structure of the shell
structure 1.
[0047] The closed liquid tank 12 may be provided with projecting
heat-exchanging elements 22 extending from the support section 26
of the shell structure 1 into the closed liquid tank 12 for serving
as heat exchanging elements between liquid 11 in the closed liquid
tank 12 and the shell structure 1 of the propulsion unit for
enhancing transfer of thermal energy between liquid in the closed
liquid tank 12 and water surrounding the propulsion unit, as shown
in FIG. 3.
[0048] The closed liquid cooling system 9 may be in the form of a
closed liquid circulation cooling system 14 having said inner space
10 containing liquid 11 and provided with liquid circulation means
15 for circulating liquid in the inner space 10 of the closed
liquid circulation cooling system 14, as in the second embodiment
of the propulsion unit illustrated in FIGS. 6 to 11, in the third
embodiment of the propulsion unit illustrated in FIGS. 12 to 17, in
the fourth embodiment of the propulsion unit illustrated in FIGS.
18 to 23, and in the fifth embodiment of the propulsion unit
illustrated in FIGS. 24 to 29.
[0049] In a such embodiments of the propulsion unit, the inner
space 10 of the closed liquid circulation cooling system 14 is
partly limited by a part 13 of the cylindrical outer surface 8 of
the cylindrical section 7 of the motor housing section 6 so that
liquid flowing in the inner space 10 of the closed liquid
circulation cooling system 14 is in direct contact with said part
13 of the cylindrical outer surface 8 of the cylindrical section 7
of the motor housing section 6 for exchanging thermal energy
between the electric motor 3 arranged in the cylindrical section 7
of the motor housing section 6 and liquid flowing in the inner
space 10 of the closed liquid circulation cooling system 14 via
said part 13 of the cylindrical section 7 of the motor housing
section 6 between the electric motor 3 and liquid circulating in
the inner space 10 of the closed liquid circulation cooling system
14.
[0050] In a such embodiments of the propulsion unit, the inner
space 10 of the closed liquid circulation cooling system 14 is
additionally partly limited by the support section 26 of the shell
structure 1 of the propulsion unit so that liquid flowing in the
inner space 10 of the closed liquid circulation cooling system 14
is in direct contact with the support section 26 of the shell
structure 1 for exchanging thermal energy between liquid flowing in
the inner space 10 of the closed liquid circulation cooling system
14 and water surrounding the support section 26 of the shell
structure 1 via the support section 26 of the shell structure
1.
[0051] If the closed liquid cooling system 9 is in the form of a
closed liquid circulation cooling system 14 provided with liquid
circulation means 15 for circulating liquid in the inner space 10
of the closed liquid circulation cooling system 14, said part 13 of
the cylindrical outer surface 8 of the cylindrical section 7 of the
motor housing section 6 partly limiting the inner space 10 of the
closed liquid circulation cooling system 14 is preferably, but not
necessarily, provided with partition elements 16 for creating
several individual channels for liquid along said part of the
cylindrical outer surface 8 of the cylindrical section 7 of the
motor housing section 6.
[0052] If the closed liquid cooling system 9 is in the form of a
closed liquid circulation cooling system 14 having said inner space
10 containing liquid 11 and provided with liquid circulation means
15 for circulating liquid in the inner space 10 of the closed
liquid circulation cooling system 14, the closed liquid circulation
cooling system 14 may be provided with a first liquid tank 17 at a
point of the closed liquid circulation cooling system 14 where the
inner space 10 of the closed liquid circulation cooling system is
partly limited by said part 13 of the cylindrical section 7 of the
cylindrical outer surface 8 of the motor housing section 6 as in
the third embodiment of the propulsion unit illustrated in FIGS. 12
to 17 and in the fifth embodiment of the propulsion unit
illustrated in FIGS. 24 to 29.
[0053] Such first liquid tank 17 has a first inner space (not
marked with a reference numeral) that forms a part of the inner
space 10 of the closed liquid circulation cooling system 14.
[0054] Such first liquid tank 17 is in fluid communication with the
closed liquid circulation cooling system 14 such that liquid
flowing in the closed liquid circulation cooling system 14 flows
through the first inner space of the first liquid tank 17.
[0055] The first inner space of the first liquid tank 17 is partly
limited by said part 13 of the cylindrical outer surface 8 of the
cylindrical section 7 of the motor housing section 6 so that liquid
in the first inner space of the first liquid tank 17 is in direct
contact with the cylindrical outer surface 8 of the cylindrical
section 7 of the motor housing section 6 for exchanging thermal
energy between the electric motor 3 arranged in the cylindrical
section 7 of the motor housing section 6 and liquid flowing in the
first inner space of the first liquid tank 17 via said part 13 of
the cylindrical outer surface 8 of the motor housing section 6.
[0056] Such first liquid tank 17 may additionally be partly limited
by the support structure 26 of the shell structure 1 so that liquid
11 in the first inner space of the first liquid tank 17 is in
direct contact with the support structure 26 of the shell structure
1 for exchanging thermal energy between liquid flowing in the first
inner space of the first liquid tank 17 of the closed liquid
circulation cooling system 14 and water surrounding the support
structure 26 of the shell structure 1 via the support structure 26
of the shell structure 1.
[0057] The first inner space of such first liquid tank 17 may be
provided with baffles 18 for guiding liquid through the first inner
space of the first liquid tank 17 to prolong the residence time of
liquid in the first inner space of the first liquid tank 17 and/or
for serving as heat exchanging elements between liquid flowing
through the first inner space of the first liquid tank 17 and the
support structure 26 of the shell structure 1.
[0058] Such first liquid tank may be provided with projecting
heat-exchanging elements 22 extending from the shell structure 1
into the first liquid tank 17 for serving as heat exchanging
elements between liquid flowing through the first liquid tank 17
and the shell structure 1 of the propulsion unit for enhancing
transfer of thermal energy between the electric motor 3 in the
motor housing section 6 and liquid in the first liquid tank 17, as
shown in drawings 15 and 26.
[0059] If the closed liquid cooling system 9 is in the form of a
closed liquid circulation cooling system 14 having said inner space
10 containing liquid and provided with liquid circulation means 15
for circulating liquid in the inner space 10 of the closed liquid
circulation cooling system 14, the closed liquid circulation
cooling system 14 may be provided with a second liquid tank 19 at a
point of the closed liquid circulation cooling system where the
closed liquid circulation cooling system is partly limited by the
support section 26 of the shell structure 1 of the propulsion unit
so that the second liquid tank 19 is partly limited by said part of
the support section 26 of the shell structure 1, as in the fourth
embodiment of the propulsion unit illustrated in FIGS. 18 to 23 and
in the fifth embodiment of the propulsion unit illustrated in FIGS.
24 to 29.
[0060] The second liquid tank 19 has a second inner space (not
marked with a reference numeral) that forms a part of the inner
space 10 of the closed liquid circulation cooling system 14.
[0061] The second liquid tank 19 is in fluid communication with the
closed liquid circulation cooling system 14 such that liquid
flowing in the closed liquid circulation cooling system 14 flows
through the second inner space of the second liquid tank 19.
[0062] Such second liquid tank 19 is partly limited by the support
section 26 of the shell structure 1 so that liquid in the second
inner space of the second liquid tank 19 is in direct contact with
the support section 26 of the shell structure 1 for exchanging
thermal energy between liquid flowing in the second inner space of
the second liquid tank 19 of the closed liquid circulation cooling
system 14 and water surrounding the support section 26 of the shell
structure 1 via the support section 26 of the shell structure
1.
[0063] The second inner space of such second liquid tank 19 may be
provided with baffles 18 for guiding liquid through the second
inner space of the second liquid tank 19 to prolong the residence
time of liquid in the second inner space of the second liquid tank
19 and/or for serving as heat exchanging elements between liquid
flowing through the second inner space of the second liquid tank 19
and the support structure 26 of the shell structure 1.
[0064] Such second liquid tank 19 may be provided with projecting
heat-exchanging elements (not shown in the drawings) extending from
the support structure 26 of the shell structure 1 into the second
liquid tank 19 for serving as heat exchanging elements between
liquid flowing through the second liquid tank 19 and said part of
the shell structure 1 of the propulsion unit for enhancing transfer
of thermal energy between water surrounding the support structure
26 of the shell structure 1 and liquid in the closed liquid cooling
system 9.
[0065] In the propulsion unit, the lower end of the support section
26 of the shell structure 1 may connected to the motor housing
section 6 of the shell structure 1 so that the cylindrical outer
surface 8 of the cylindrical section 7 of the motor housing section
6 of the shell structure 1 of the propulsion unit partly forms the
outermost surface of the propulsion unit, as is the case in the
embodiments shown in the drawings. Such part of the cylindrical
outer surface 8 of the cylindrical section 7 of the motor housing
section 6 forming the outermost surface of the propulsion unit may
be provided with projecting heat-exchanging elements 20 for
enhancing transfer of thermal energy between the electric motor 3
in the motor housing section 6 and water surrounding the part of
the cylindrical section 7 of the motor housing section 6 forming
the outermost surface of the propulsion unit, as is the case in the
embodiments shown in the drawings 4, 9, 15, 21, and 26.
[0066] The propulsion unit the support section 26 of the shell
structure 1 may in some embodiments be provided with a cavity 25 in
fluid communication with water surrounding the shell structure 1
for allowing water surrounding the shell structure to enter the
cavity 25 and to exit the cavity 25. A such embodiment is shown in
FIGS. 30 to 36. In such embodiments the closed liquid circulation
cooling system 14 comprises a tube section 29 so that the inner
space of the closed liquid circulation cooling system 14 is partly
limited by the tube section 29. In such embodiments the tube
section 29 is arranged in the cavity 25 so that an outer surface of
the tube section 29 is in the cavity 25 in direct contact with
water surrounding the shell structure 1. The tube section 29 may be
a part of a liquid-liquid-heat exchanger for exchanging thermal
energy between liquid in the inner space 10 of the closed liquid
circulation cooling system 14 and water surrounding the shell
structure, which liquid-liquid-heat exchanger is arranged in the
cavity 25. If the support section of the shell structure is
provided with a cavity 25 in fluid communication with water
surrounding the shell structure 1 for allowing water surrounding
the shell structure 1 to enter the cavity 25 and to exit the cavity
25, the cavity 25 may, as shown in FIG. 32, be at least partly
closed by at least one cover 27 forming a part of the shell
structure 1. A such cover 27 may be provided with at least one
opening 28 for allowing water surrounding the shell structure 1 to
enter the cavity 25 and to exit the cavity 25.
[0067] In the propulsion unit, the cylindrical section 7 of the
motor housing section 6 is preferably, but not necessarily, of a
single-layer construction, as is the case in the embodiments shown
in the drawings.
[0068] In the propulsion unit, the part of the cylindrical outer
surface 8 of the cylindrical section 7 of the motor housing section
6 in contact with liquid in the closed liquid cooling system 9 is
preferably, but not necessarily, provided with projecting
heat-exchanging elements 21 for enhancing transfer of thermal
energy between the electric motor 3 in the motor housing section 6
and liquid in the second liquid tank, as shown in drawings 3, 4, 9,
11, 15, 17, 21, 23, 26 and 28.
[0069] In the propulsion unit, the closed liquid cooling system 9
is preferably, but not necessarily, arranged fully enclosed by the
shell structure 1 of the propulsion unit as is shown in the
drawings.
[0070] In the propulsion unit, the electric motor 3 is preferably,
but not necessarily, a permanent-magnet electric motor 3.
[0071] It is apparent to a person skilled in the art that as
technology advances, the basic idea of the invention can be
implemented in various ways. The invention and its embodiments are
therefore not restricted to the above examples, but they may vary
within the scope of the claims.
* * * * *