U.S. patent application number 17/648882 was filed with the patent office on 2022-07-28 for marine drive unit and marine vessel.
This patent application is currently assigned to VOLVO PENTA CORPORATION. The applicant listed for this patent is VOLVO PENTA CORPORATION. Invention is credited to Lennart ARVIDSSON.
Application Number | 20220234708 17/648882 |
Document ID | / |
Family ID | |
Filed Date | 2022-07-28 |
United States Patent
Application |
20220234708 |
Kind Code |
A1 |
ARVIDSSON; Lennart |
July 28, 2022 |
MARINE DRIVE UNIT AND MARINE VESSEL
Abstract
A hybrid marine drive unit mounted to a transom. The drive unit
includes a drive housing rigidly mounted on the transom, a
propelling unit rotatable about a vertical axis and mounted to a
lower surface of the drive housing, and a transmission with at
least a vertical drive shaft located in the drive housing and
extending into the propelling unit, which vertical drive shaft is
arranged transmit drive torque from at least one of multiple
sources of drive torque. The vertical drive shaft is operably
connected to at least one first source of drive torque arranged
within the drive housing, and the vertical drive shaft is operably
connected to a horizontal output shaft extending into the drive
housing through the transom.
Inventors: |
ARVIDSSON; Lennart;
(Kallered, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VOLVO PENTA CORPORATION |
Goteborg |
|
SE |
|
|
Assignee: |
VOLVO PENTA CORPORATION
Goteborg
SE
|
Appl. No.: |
17/648882 |
Filed: |
January 25, 2022 |
International
Class: |
B63H 20/02 20060101
B63H020/02; B63H 23/04 20060101 B63H023/04; B63H 23/06 20060101
B63H023/06; B63H 20/12 20060101 B63H020/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2021 |
EP |
21153776.6 |
Claims
1. Hybrid marine drive unit configured to be mounted to a transom
of a marine vessel, which drive unit comprises a drive housing
configured to be rigidly mounted at the transom, a propelling unit
rotatable about a vertical axis and mounted to a lower surface of
the drive housing, wherein the propelling unit is arranged to be
rotatable relative to the lower surface of the drive housing by a
steering arrangement in order to steer the vessel, and a
transmission with at least a vertical drive shaft located in the
drive housing and extending into the propelling unit, which
vertical drive shaft is arranged to transmit drive torque from at
least one of multiple sources of drive torque, wherein: the
vertical drive shaft is operably connected to at least one first
source of drive torque arranged within the drive housing, and that
the vertical drive shaft is operably connected to a horizontal
output shaft extending into the drive housing, wherein the
horizontal output shaft is configured to extend through the transom
when the hybrid marine drive unit is mounted at the transom of the
marine vessel, wherein the horizontal output shaft is connectable
to a second source of drive torque located within a hull of the
vessel.
2. Hybrid marine drive unit according to claim 1, wherein the first
source of drive torque is an electric motor with an independently
excited rotor; wherein the rotor is arranged to be freewheeling
when its excitation current is deactivated.
3. Hybrid marine drive unit according to claim 2, wherein the at
least one electric motor is a polyphase synchronous motor, a
switched reluctance motor or a synchronous reluctance motor.
4. Hybrid marine drive unit according to claim 1, wherein the at
least one first source of drive torque is operably connected to an
upper end or portion of the vertical drive shaft above a gear
unit.
5. Hybrid marine drive unit according to claim 2, wherein the at
least one electric motor is directly connected to the propelling
unit via the vertical drive shaft.
6. Hybrid marine drive unit according to claim 2, wherein the at
least one electric motor is operably connected to the vertical
drive shaft by a gear unit.
7. Hybrid marine drive unit according to claim 6, wherein the first
and second sources of drive torque are operably connected to the
vertical drive shaft via the gear unit.
8. Hybrid marine drive unit according to claim 1, wherein the
horizontal output shaft is operably connected to the vertical drive
shaft via a gear unit.
9. Hybrid marine drive unit according to claim 4, wherein the gear
unit comprises opposing bevel gears operatively connected to the
horizontal output shaft, wherein each bevel gear is connected or
disconnected to the vertical drive shaft by a controllable
actuator.
10. Hybrid marine drive unit according to claim 9, wherein the
controllable actuator is a clutch.
11. Hybrid marine drive unit according to claim 1, wherein each
source of drive torque is arranged to drive the vertical drive
shaft independently or in combination.
12. Hybrid marine drive unit according to claim 1, wherein the
drive housing comprises a control unit and power electronic
controller for the at least one electric motor.
13. Hybrid marine drive unit according to claim 1, wherein the
drive housing comprises a steering system with a control unit and a
steering drive unit for rotating the propelling unit about its
vertical axis.
14. Marine vessel with a hybrid driveline comprising multiple
sources of drive torque to propel the vessel, wherein the vessel is
provided with at least one hybrid marine drive unit according to
claim 1, and wherein the drive housing is rigidly mounted at the
transom of the vessel with the horizontal output shaft extending
through the transom.
15. Marine vessel according to claim 14, wherein the at least one
hybrid marine drive unit comprises at least one electric motor
arranged within a drive housing and that the drive unit is
operatively connected to an internal combustion engine arranged
within the hull of the vessel.
Description
TECHNICAL FIELD
[0001] The present invention relates to a marine drive unit and a
marine vessel with a hybrid driveline comprising such a drive
unit.
BACKGROUND
[0002] Known marine vessels comprising a propulsion unit in the
form of a pod drive are usually provided with an internal
combustion engine (ICE) arranged within the hull of the vessel.
Torque is then transmitted from the ICE to the drive via a
transmission comprising shafts and gearing in order to drive a set
of propellers on a steerable drive unit mounted to the hull.
[0003] When operating a vessel of this type at low speed it is
sometimes desirable to be able to drive the vessel at reduced noise
levels and/or without exhaust emissions. Operating conditions when
this is an advantage is for instance when manoeuvring within a
marina, while trolling or during docking. A possible solution to
the above problems can be to provide an individual electric motor.
However, such motors are more suited for smaller vessels with an
outboard motor and are usually too small for operating vessels
comprising one or more inboard engines with pod drives. A further
solution to the problem is to provide a hybrid driveline with the
inboard engine and electric motor arranged in series. Such a
solution is known from US 2011/195618. A problem with this solution
is that it takes up more space within the hull, reducing
accommodation space for the occupants. Further, the control system
for the engine and electric motor must be combined and becomes more
complex. Such a control system will at best be difficult to adapt
to an existing inboard driveline comprising one or more engines.
Also, combining such a hybrid driveline with a pod drive will
require additional space for the transmission and steering
arrangement extending through the hull to the steerable pod beneath
the hull.
[0004] The invention provides an improved marine drive unit aiming
to solve the above-mentioned problems.
SUMMARY
[0005] An object of the invention is to provide a marine drive unit
for a vessel, which drive unit solves the above-mentioned
problems.
[0006] The object is achieved by a hybrid marine drive unit and a
marine vessel with a hybrid driveline comprising such a drive unit
according to the appended claims.
[0007] In the subsequent text, the term "drive unit" means an
assembly comprising an outdrive having two sub-units. An upper
sub-unit comprises a drive housing containing at least one source
of drive torque and a transmission comprising a vertical driveshaft
partly enclosed by the drive housing. The drive housing is
preferably, but not necessarily, completely submerged. A lower
sub-unit forms a propulsor or propelling unit and contains an
extension of the vertical driveshaft and a transmission comprising
a gearbox providing power to a propeller shaft/-s for driving at
least one propeller. The transmission in the lower sub-unit
supplies power from the transmission in the upper sub-unit to the
propellers. The component parts of the transmission in the lower
sub-unit are enclosed in a gearbox housing. At least one drive unit
is mounted to the transom of a marine vessel and forms part of a
hybrid driveline comprising a first source of drive torque within
the drive unit and an inboard, second source of drive torque. The
terms "inboard" or "on-board" are used to indicate that a component
is located within the hull of the vessel, i.e. not within the drive
unit or its housing.
[0008] According to a first aspect of the invention, the invention
relates to a hybrid marine drive unit arranged to be mounted to a
transom on a marine vessel. The drive unit comprises a drive
housing that is configured to be rigidly mounted at or on the
transom, and is preferably, but not necessarily, submerged during
operation. That the drive housing is rigidly mounted to the transom
means that it is stationary in relation to the transom during
operation, i.e. in contrast to a conventional stern drive where the
housing is arranged to pivot (together with a propelling unit)
about a vertical axis at the transom for at least steering. The
drive unit further comprises a propelling unit rotatable about a
vertical axis and mounted to a lower surface of the drive housing
and a transmission with at least a vertical drive shaft located in
the drive housing. The drive unit is an azimuthing pod drive
removably attached to the transom. The propelling unit is arranged
to be rotatable relative to the lower surface of the drive housing
by a steering arrangement in order to steer the vessel. The
vertical drive shaft is arranged to transmit drive torque from
multiple sources of drive torque to the propelling unit for
propelling the vessel. The vertical drive shaft is operably
connected to at least one first source of drive torque arranged
within the drive housing. In addition, the vertical drive shaft is
also operably connected to a horizontal output shaft extending into
the drive housing through the transom, wherein the horizontal
output shaft is connectable to a second source of drive torque.
[0009] The first source of drive torque is preferably an electric
motor with an independently excited rotor, wherein the rotor is
arranged to be freewheeling when its excitation current is
deactivated to demagnetize the rotor. A non-exhaustive list of
suitable electric motors comprises polyphase synchronous motors,
switched reluctance motors or synchronous reluctance motors.
[0010] The vertical drive shaft is operably connected to at least
one first source of drive torque in the form of an electric motor
arranged within the drive housing. According to one example, an
electric motor with a vertical output shaft can be operably
connected to the upper end or portion of the vertical drive shaft.
According to this example, the electric motor comprises a vertical
output shaft drivingly connected to the vertical drive shaft
extending directly into the propelling unit. For this electric
motor, switching between a connected torque transmitting state and
a disconnected freewheeling state relative to the vertical drive
shaft is achieved by demagnetizing its rotor. This allows the
vertical drive shaft to rotate without resistance from the electric
motor, for instance, when propelling the vessel using the second
source of drive torque only.
[0011] One or more additional sources of drive torque can be
operably connected to the vertical drive shaft by a suitable gear
unit. The gear unit can comprise a number of gears, such as bevel
gears, wherein each gear is associated with a horizontal driving
input shaft from a first source of drive torque or a driven output
shaft from the second source of drive torque. Preferably, a single
common gear unit is used for this purpose. The gears are preferably
switchable between a connected, torque transmitting state and a
disconnected, freewheeling state relative to their respective
shaft. For additional first sources of drive torque comprising
electric motors switching can be achieved by demagnetizing the
rotor of the respective motor. According to a further example the
at least one first source of drive torque comprises an electric
motor with a vertical output shaft, as described above, and at
least one electrical motor with a horizontal output shaft which can
be operably connected to the gear unit. According to a further
example the at least one first source of drive torque comprises at
least one electrical motor with a horizontal output shaft which can
be operably connected to the gear unit.
[0012] The drive unit is part of a hybrid driveline, wherein a
first source of drive torque is an electric motor and a second
source of drive torque can be an internal combustion engine.
Consequently, the vertical drive shaft is operably connected to a
second source of drive torque in the form of an internal combustion
engine. The horizontal output shaft from the second source of drive
torque is operably connected to the vertical drive shaft via the
common gear unit. A separate clutch is provided for disconnecting
the second source of drive torque from the gear unit during
electrical operation of the drive unit. This clutch can be a
friction clutch located adjacent the second source of drive torque
within the hull of the vessel. Preferably, the second source of
drive torque is operably connected to the vertical drive shaft via
the gear unit comprising multiple bevel gears in driving
connection. The at least one electric motor is operably connected
directly to the vertical drive shaft and/or indirectly via the gear
unit, as described above.
[0013] The horizontal output shafts from the internal combustion
engine and/or at least one electric motor are operably connected to
the vertical drive shaft via the common gear unit. The common gear
unit can comprise a bevel gear mounted on each of the horizontal
output shafts from the one or more electric motors and the internal
combustion engine. Each driving bevel gear is operably connected
with a pair of driven opposed bevel gears operatively connectable
to the vertical drive shaft. When driven, the bevel gear on either
one of the driving horizontal shafts will drive both the opposed
bevel gears. The bevel gears on the vertical drive shaft are
provided with controllable actuators allowing each gear to be
placed in driving connection with the vertical drive shaft in turn.
For the second source of drive torque one bevel gear is connected
for forward propulsion and the opposite bevel gear is connected for
reverse propulsion. Alternatively, both bevel gears can rotate
freely relative to the vertical drive shaft.
[0014] Switching the bevel gears between a connected torque
transmitting state and a disconnected freewheeling state relative
to the vertical drive shaft is achieved by actuation or deactuation
of a suitable controllable actuator in the form of a mechanical
actuator or a fluid (hydraulically or pneumatically) operated
clutch. An example of a suitable clutch is a wet or dry multi-plate
clutch, also termed lamella clutch. Hence, torque transmission from
each drive source is controllable between its connected and
disconnected states by a corresponding actuator mounted adjacent
the respective gear, preferably within the gear unit.
[0015] As described above, the marine drive unit comprises a
propelling unit, such as a propeller, impeller or pod drive mounted
to the lower surface of the drive housing. The propelling unit is
arranged to be rotatable relative to the lower surface of the drive
housing by a steering system in order to steer the vessel. The
steering arrangement is located in the drive housing and comprises
a steering system with a control unit and a steering drive unit for
rotating the propelling unit about its vertical axis. The steering
drive unit can comprise an electric motor. The propelling unit can
comprise counter rotating forward facing propellers in the form of
an azimuthing pod.
[0016] The drive housing can comprise a control unit and power
electronics controller (PEC) for the at least one electric motor
and for the steering arrangement. The outer enclosure for the drive
housing provides a thermal mass to absorb the heat generated by the
electric motor or the power electronics. In operation, the drive
housing is immersed in water and the water provides effective
convection cooling. The electric motor is connected to the PEC,
which supplies current to the at least one electric motor from an
energy storage, such as a high voltage battery pack via a
propulsion voltage system comprising high voltage DC buses and a
high voltage junction box. The high voltage junction box can also
be used for joining and distributing high voltage buses to a number
of different electrical components on-board the vessel. The battery
pack can comprise a separate power electronics controller (PEC) and
an electronic controller for calibrating and charging the battery
pack. Power electronics controllers of this type are known in the
art and will not be described in further detail here.
[0017] According to a further example, the drive housing can
comprise a closed coolant and lubrication circuit for the
transmission, including the gear unit and propeller unit, and the
at least one electric motor. The drive housing can comprise a
reservoir for a liquid lubricant and coolant. The closed coolant
and lubrication circuit comprises a pump, a supply conduit
connected to conduits for the electric motors and the transmission,
and a return conduit connected to the reservoir. The pump is
preferably, but not necessarily, located in the reservoir. The
provision of a closed coolant and lubrication circuit allows the
drive unit to be cooled without the use of water from the
surrounding body of water. This is a particular advantage if the
vessel is operated in saline or polluted waters. A further
advantage is that the same system can be used for lubrication,
wherein separate pumps and circuits for cooling and lubrication can
be dispensed with, which provides a reduction of both cost and
space requirement.
[0018] According to a second aspect of the invention, the invention
relates to a marine vessel with a hybrid driveline comprising
multiple sources of drive torque to propel the vessel, wherein the
vessel is provided with at least one marine drive unit as described
above. The at least one drive unit comprises at least one electric
motor arranged within a drive housing and that the drive unit is
operatively connected to an internal combustion engine arranged
within the hull of the vessel. Exhaust from the internal combustion
engine can be discharged through a suitable port through the hull
or below the waterline through the propelling unit.
[0019] The drive unit according to the invention provides a way to
mount a pod drive with a hybrid driveline without requiring
significant modifications of a marine vessel intended for stern
drive applications. In most cases the outer drive unit can be
advantageously provided with a drive housing having the same or
approximately the same shape and size as conventional stern drive
housings. Further, the interface for mounting a pod drive and its
steering gear connections to the transom can be maintained. For
marine vessel intended for pod drive applications the invention
eliminates the need for a sizable opening through the lower surface
of the hull which is required for most types of pod drives, such as
an IPS .COPYRGT. pod drive manufactured by Volvo Penta. Further, by
mounting the electric motors in the outer drive housing, it is
possible to provide a hybrid drive unit without taking up space for
electric motors or the pod drive itself within the hull. The
provision of one or more on-board battery packs can be achieved
without taking up accommodation space. The electric motor/-s and
the inboard engine can drive the propellers together, independently
or in variable combinations in response to different torque and
power demands whereby the efficiency of the drive unit is improved.
By allowing independent operation of at least a single motor the
arrangement provides a redundancy for the drive unit and ensures
that the vessel can be operated even if the engine or one or more
electric motors are inoperable.
[0020] Further advantages and advantageous features of the
invention are disclosed in the following description and in the
dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] With reference to the appended drawings, below follows a
more detailed description of embodiments of the invention cited as
examples. In the drawings:
[0022] FIG. 1 shows a lower perspective view of a schematically
illustrated vessel comprising a pair of drive units;
[0023] FIG. 2 shows a schematic side view of a driveline according
to a first example;
[0024] FIG. 3 shows a schematic side view of a driveline according
to a second example;
[0025] FIG. 4 shows a schematic side view of a driveline according
to a third example;
[0026] FIG. 5 shows a schematic transmission for the driveline in
FIG. 2;
[0027] FIG. 6 shows a schematic transmission for the driveline in
FIG. 3; and
[0028] FIG. 7 shows a schematic transmission for the driveline in
FIG. 4.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION
[0029] FIG. 1 shows a lower perspective view of a schematically
illustrated marine vessel 100 comprising two marine drive units
103, 103' according to the invention. In this example, the marine
drive units 103, 103' are identical and only one will be described
in further detail below. The marine drive units 103, 103' are
mounted to a transom 102 on the vessel 100. Each marine drive unit
103, 103' comprises an upper and a lower unit, wherein the upper
unit is a drive housing 104, 104' rigidly mounted on the transom
102. The lower unit is a propelling unit 105, 105' rotatable about
a vertical axis and mounted to a lower surface 106, 106' of each
drive housing 104, 104'. The schematically indicated marine drive
units 103, 103' in FIG. 1 are preferably located below the
waterline of the vessel hull 101. The example shown in FIG. 1 shows
propelling units in the form of steerable pods which comprise twin
forward facing, pulling propellers 107, 107'. As will be described
below, alternative propelling units can be employed within the
scope of the invention.
[0030] The marine drive units in FIG. 1 are controllable by a
control means (not shown) such as a throttle lever located at an
operating position on-board the vessel. The throttle lever can be
connected to an electronic control unit (ECU) via suitable wiring,
which ECU is connected to a source of energy, such as a battery
pack or a fuel cell via additional wiring. Such an energy source is
located within the hull of the vessel and can comprise a power
electronic controller (PEC) and an electronic controller for
calibrating and charging a battery pack. The throttle lever be used
for controlling the first source of drive torque, such as at least
one electric motor within the drive housing, and the second source
of drive torque, such as an engine located within the hull of the
vessel. The first and second sources of drive torque form a hybrid
driveline and the sources can be operated individually or together.
Electronic controllers of this type are known in the art and will
not be shown or described in further detail here.
[0031] FIG. 2 shows a cross-sectional side view of a drive unit 203
according to a first example shown in FIG. 1. FIG. 2 shows the
drive unit 203 mounted to a transom 202 of a marine vessel (see
FIG. 1). The drive unit 203 comprises an upper drive housing 204,
and a lower propelling unit 205, where the propelling unit 205 is
rotatably mounted to a lower surface 206 of the drive housing 204
in order to steer the vessel. The drive housing 204 encloses a
transmission comprising a vertical drive shaft 210 arranged
transmit drive torque from at least one source of drive torque to a
pair of forward-facing counter rotating propellers 207 on the
propelling unit 205. The transmission further comprises a gear unit
213 operably connectable to an upper end of the vertical drive
shaft 210. In FIG. 2, a first source of drive torque is an electric
motor 211 with a vertical output shaft 212 that is operably
connected to the vertical drive shaft 210 directly through the gear
unit 213. The electric motor 211 can be disconnected from the
through shaft comprising the vertical drive shaft 210 and the
vertical output shaft 212 by demagnetizing the rotor. A horizontal
output shaft 220 is connected to a second source of drive torque in
the form of an inboard ICE 221 located within the hull of the
vessel (see FIG. 2).
[0032] The gear unit 213 comprises a set of bevel gears 214, 215,
216 which are in constant driving contact with each other. Each
bevel gear is associated with a respective driving or driven shaft
212, 210, 220 and is switchable between a connected state and a
disconnected state for transferring torque to the vertical drive
shaft 210. The bevel gear 216 is fixed to the horizontal output
shaft 220 and is switchable between a driven state and a
freewheeling state by a main clutch 224 adjacent the ICE 221. Each
bevel gear 214, 215 on the vertical drive shaft 210 is controllable
between its connected and disconnected states by a corresponding
actuatable clutch 214', 215' mounted adjacent the respective bevel
gear (see FIG. 5). Switching can be achieved by actuation or
deactuation of a suitable controllable clutch or mechanical
actuator. In the subsequent text switching is performed using wet
or dry multi-plate clutches, or lamella clutches, hereafter
referred to as "clutches". Lamella clutches of this type can be
pneumatically or hydraulically actuated using a suitable source of
fluid pressure. The design or control of such clutches is known in
the art and will not be described in further detail here.
[0033] In FIGS. 2 and 6, the vertical output shaft 212 of the
electric motor 211 passes through the gear unit 213. The gear unit
213 comprises an upper first bevel gear 214 arranged on the
vertical output shaft 212 and a lower second bevel gear 215
arranged on the vertical drive shaft 210. The first and second
bevel gears 214, 215 are in driving connection with the
intermediate third bevel gear 216 arranged on the horizontal output
shaft 220. The horizontal output shaft 220 is connected to a second
source of drive torque in the form of an inboard ICE 221 located
within the hull of the vessel (see FIG. 1). The horizontal output
shaft 220 passes through a seal 222 in the transom 202 and is fixed
in a vibration absorbing bushing 223 supported by the ICE output
shaft. The clutch 224 is provided between the horizontal output
shaft 220 and the ICE crankshaft to control the rotation of the
horizontal output shaft 220. The first and second bevel gears 214,
215 are freely rotatable about the vertical output shaft 212 and
the vertical drive shaft 210, respectively, in their disconnected
state. Similarly, the third bevel gear 216 is freely rotatable with
the horizontal output shaft 220 when the clutch 224 adjacent the
ICE221 in its disconnected state. The bevel gears 214, 215 are
selectably connected to the vertical drive shaft 210 in order to
transmit torque from the ICE 221 to the vertical drive shaft 210
and the propellers. In this way, the vertical drive shaft 210 can
be operably connected to the horizontal output shaft 220 which
extends out of the drive housing 204 through the transom 202.
[0034] In operation, the driveline can be operated in electric mode
using the electric motor 211 rotating the vertical output shaft 212
and the vertical drive shaft 210 directly as shown in FIGS. 2 and 5
to drive the vessel in a forward direction. FIG. 5 shows a
schematic view of the transmission for the driveline in FIG. 2. In
the electric mode, the rotor of the electric motor 211 is
magnetized and the bevel gears 214, 215 are disconnected from the
vertical drive shaft 210. Propelling the vessel in a reverse
direction is achieved by switching the direction of rotation of the
electric motor 211.
[0035] Alternatively, the driveline can be operated in ICE mode,
wherein the rotor (not shown) of the electric motor 211 is
demagnetized making the vertical output shaft 212 freely rotatable
relative to the motor. In the gear unit 213, the first bevel gear
214 is maintained disconnected while the second bevel gear 215 is
connected to the vertical drive shaft 210 by actuation of the
clutch 215'. At the same time, the third bevel gear 216 is driven
by the horizontal output shaft 220 by actuation of the main clutch
224. The ICE 221 can then be operated to transmit torque to the
horizontal shaft 220 and the vertical drive shaft 210 via the third
bevel gear 216 and the second bevel gear 215, in order to propel
the vessel in a forward direction. In order to propel the vessel in
a reverse direction the main clutch 224 is deactuated. The second
bevel gear 215 is then disconnected by deactuation of the clutch
215', while the first bevel gear 214 is connected to the vertical
output shaft 212 by actuation of the clutch 214'. Subsequently, the
third bevel gear 216 continues to be driven by the horizontal
output shaft 220 by actuation of the main clutch 224. The ICE 221
can then be operated to transmit torque to the horizontal shaft 220
and the vertical drive shaft 210 via the third bevel gear 216 and
the first bevel gear 214.
[0036] According to a further example, the driveline can be
operated in a hybrid mode using the electric motor 211 and the ICE
221 together. In the hybrid mode, the gear unit 213 is operated in
the same way as in the ICE mode described above, wherein the rotor
of the electric motor 211 is magnetized so that the motor can be
operated to drive the vertical output shaft 212 to assist the ICE
221. The direction of rotation of the electric motor 211 is
selected to correspond with the direction of rotation of the
currently connected first or second bevel gear 214, 215.
[0037] The propelling unit 205 contains a gearbox 208 operably
connected to a lower end of the vertical drive shaft 210, which can
be rotated as shown by the arrow A.sub.1 to drive the counter
rotating propellers 207. Gearboxes for driving counter-rotating
shafts of this type are well known and will not be described in
further detail.
[0038] The drive housing 204 further comprises a control unit and
power electronics controller (PEC) 230 for the electric motor 211.
The combined control unit and power electronics controller (PEC)
230 is also used for controlling a steering arrangement 240
described below. The outer enclosure for the drive housing 204
provides a thermal mass to absorb the heat generated by the
electric motor 211 and the PEC 230. In operation, the drive housing
204 is immersed in water and the water provides effective
convection cooling. The electric motor 211 is connected to the PEC
230, which supplies current to the electric motor 211 from an
inboard energy storage (not shown). Control means such as a
throttle and a steering means (not shown) are provided at an
operator station on-board the vessel.
[0039] The propelling unit 205 is arranged to be rotatable relative
to the lower surface 206 of the drive housing by a steering
arrangement 240 in order to steer the vessel. The steering
arrangement 240 is located in the drive housing comprises a
steering system with a control unit and a steering drive unit for
rotating the propelling unit about its vertical axis. The steering
drive unit can comprise an electric motor. The steering drive unit
drives a steering transmission comprising a pinon gear that drives
a gear fixed to the propelling unit 205 about the central axis X of
the vertical drive shaft 210 as indicated by the arrow A.sub.2.
[0040] The drive housing 204 in FIG. 2 further comprises a coolant
and lubricant circuit 250. FIG. 2 schematically indicates a closed
coolant and lubrication circuit for the gear unit 213, the vertical
drive shaft 210, the steering arrangement 240 and the electric
motor 211. The closed coolant and lubrication circuit comprises a
pump, a reservoir, a supply conduit connected to conduits for
cooling the electric motor 211 and a conduit supplying the
coolant/lubricant to the gear unit and steering arrangement. The
provision of a closed coolant and lubrication circuit allows
internal components to be cooled without using water from the
surrounding body of water. As described above, the outer enclosure
of the drive housing 204 can provide additional cooling by using it
as a thermal mass to absorb the heat generated by the electric
motor 211 and the PEC 230. The arrangement also allows the same
system to be used for both cooling and lubrication.
[0041] FIG. 3 shows a schematic side view of a driveline according
to a second example. FIG. 3 shows the drive unit 303 mounted to a
transom 302 of a marine vessel (see FIG. 1). The drive unit 303
comprises an upper drive housing 304, and a lower propelling unit
305, where the propelling unit 305 is rotatably mounted to a lower
surface 306 of the drive housing 304 in order to steer the vessel.
The drive housing 304 encloses a transmission comprising a vertical
drive shaft 310 arranged to transmit drive torque from at least one
source of drive torque to a pair of forward-facing counter rotating
propellers 307 on the propelling unit 305. The transmission further
comprises a gear unit 313 operably connectable to an upper end of
the vertical drive shaft 310, which passes directly through the
gear unit 313. In FIGS. 3 and 6, a first source of drive torque is
an electric motor 311 with a horizontal output shaft 312 that is
operably connectable to the vertical drive shaft 310 directly
through the gear unit 313. FIG. 6 shows a schematic view of the
transmission for the driveline in FIG. 3. The electric motor 311
can be disconnected from the horizontal output shaft 312 and the
through shaft comprising the vertical drive shaft 310 and a
vertical support shaft 318 by demagnetizing the rotor. A horizontal
output shaft 320 is connected to a second source of drive torque in
the form of an inboard internal combustion engine (ICE) 321 located
within the hull of the vessel (see FIG. 3 or 1).
[0042] The gear unit 313 comprises a set of bevel gears 315, 316,
317, 319 which are in constant driving contact with each other.
Each bevel gear is associated with a respective driving or driven
shaft 310, 320, 312, 318 and is switchable between a connected
state and a disconnected state for transferring torque to the
vertical drive shaft 210. The bevel gear 316 fixed to the
horizontal output shaft 320 from the ICE 321 is switchable between
a driven state and a freewheeling state by a main clutch 324
adjacent the ICE 321. The bevel gear 317 fixed to the horizontal
output shaft 312 from the electric motor 311 is switchable between
a driven state and a freewheeling state by magnetizing and
demagnetizing the rotor of the electric motor 311. Each bevel gear
319, 315 on the vertical drive shaft 310 is controllable between
its connected and disconnected states by a corresponding actuatable
clutch 319', 315' mounted adjacent the respective bevel gear.
Switching the bevel gears 319, 315 can be achieved by actuation or
deactuation of a suitable controllable clutch or mechanical
actuator. In the subsequent text switching is performed using wet
multi-plate clutches, or lamella clutches, hereafter referred to as
"clutches". Hence, each bevel gear 319, 315 on the vertical drive
shaft 310 is controllable between its connected and disconnected
states by a corresponding actuatable clutch 319', 315' mounted
adjacent the respective bevel gear.
[0043] With reference to FIG. 6, the vertical drive shaft 310
passes directly upwards through the gear unit 313 and exits as the
upper supporting shaft 318. The gear unit 313 comprises an upper
first bevel gear 319 and a lower second bevel gear 315 arranged on
the vertical drive shaft 310. The first and second bevel gears 319,
315 are in driving connection with an intermediate third bevel gear
316 fixed to a first horizontal output shaft 320 connected to a
main clutch 324 via a main clutch 324. The first and second bevel
gears 319, 315 are further in driving connection with an
intermediate fourth bevel gear 317 arranged on a second horizontal
output shaft 312. The fourth bevel gear 317 is arranged opposite
the third bevel gear 316 coaxially with the first horizontal output
shaft 320. The second horizontal output shaft 312 is connected to a
first source of drive torque in the form of an electric motor 311.
The first horizontal output shaft 320 is connected to a second
source of drive torque in the form of an inboard ICE 321 located
within the hull of the vessel (see FIG. 1). The first horizontal
output shaft 320 passes through a seal 322 in the transom 302 and
is fixed in a vibration absorbing bushing 323 supported by the ICE
output shaft. A main clutch 324 is provided between the first
horizontal output shaft 320 and the ICE crankshaft to control the
rotation of the first horizontal output shaft 320. The first and
second bevel gears 319, 315 are freely rotatable about the
supporting shaft 318 and the vertical drive shaft 310,
respectively, in their disconnected state. Similarly, the third
bevel gear 316 is freely rotatable with the first horizontal output
shaft 320 in its disconnected state. The fourth bevel gear 317 is
freely rotatable about the second horizontal output shaft 312 with
the main clutch 324 in its disconnected state. The upper and lower
bevel gears 319, 315 are selectably connected to the vertical drive
shaft 310 in order to transmit torque from the electric motor 311
and/or the ICE 321 to the vertical drive shaft 310 and the
propellers. In this way, the vertical drive shaft 310 can be
operably connected to the first horizontal output shaft 320, which
extends out of the drive housing 304 through the transom 302, and
to the second horizontal output shaft 312.
[0044] In operation, the driveline can be operated in electric mode
using the electric motor 311 for rotating the horizontal second
output shaft 312 and the vertical drive shaft 310 to drive the
vessel in a forward direction. In this mode, the third bevel gear
316 is allowed to rotate freely by disconnection of the main clutch
324. In the gear unit 313, the first bevel gear 319 is maintained
disconnected while the second bevel gear 315 is connected to the
vertical drive shaft 310 by actuation of the lower clutch 315'. At
the same time, the rotor of the electric motor 311 is magnetized
allowing it to be operated to transmit torque to the second
horizontal output shaft 312 and the vertical drive shaft 310 via
the fourth bevel gear 317 and the second bevel gear 315, in order
to propel the vessel in a forward direction. Propelling the vessel
in reverse direction is achieved by switching the direction of
rotation of the electric motor 311.
[0045] Alternatively, the driveline can be operated in ICE mode,
wherein the rotor (not shown) of the electric motor 311 is
demagnetized making the second horizontal output shaft 312 freely
rotatable. In the gear unit 313, the first bevel gear 319 is
maintained disconnected while the second bevel gear 315 is
connected to the vertical drive shaft 310 by actuation of the
clutch 315'. At the same time, the third bevel gear 316 and the
first horizontal output shaft 320 are operatively connected to the
ICE 321 by actuation of the main clutch 324. The ICE 321 can then
be operated to transmit torque to the horizontal shaft 320 and the
vertical drive shaft 310 via the third bevel gear 316 and the
second bevel gear 315, in order to propel the vessel in a forward
direction. In order to propel the vessel in a reverse direction the
main clutch 324 is deactuated. The second bevel gear 315 is then
disconnected by deactuation of the clutch 315', while the first
bevel gear 319 is connected to the vertical support shaft 318 by
actuation of the clutch 319'. Subsequently, the third bevel gear
316 continues to be driven the horizontal output shaft 320 by
actuation of the main clutch 324. The ICE 321 can then be operated
to transmit torque to the horizontal shaft 320 and the vertical
drive shaft 310 via the third bevel gear 316 and the first bevel
gear 319.
[0046] According to a further example, the driveline can be
operated in a hybrid mode using the electric motor 311 and the ICE
321 together. In the hybrid mode, the gear unit 313 is operated in
the same way as in the ICE mode described above, wherein the rotor
of the electric motor 311 is magnetized so that the motor can be
operated to drive the vertical output shaft 312 to assist the ICE
321. The direction of rotation of the electric motor 311 is
selected to correspond with the direction of rotation of the
currently connected first or second bevel gears 314, 315 selected
for forward or reverse operation of the vessel using the ICE
321.
[0047] The propelling unit 305 contains a gearbox 308 operably
connected to a lower end of the vertical drive shaft 310, which can
be rotated as shown by the arrow A.sub.1 to drive the counter
rotating propellers 307. Gearboxes for driving counter-rotating
shafts of this type are well known and will not be described in
further detail.
[0048] The drive housing 304 further comprises a control unit and
power electronics controller (PEC) 330 for the electric motor 311.
The combined control unit and power electronics controller (PEC)
330 is also used for controlling a steering arrangement 340
described below. The outer enclosure for the drive housing 304
provides a thermal mass to absorb the heat generated by the
electric motor 311 and the PEC 330. In operation, the drive housing
304 is immersed in water and the water provides effective
convection cooling. The electric motor 311 is connected to the PEC
330, which supplies current to the electric motor 311 from an
inboard energy storage (not shown). Control means such as a
throttle and a steering means (not shown) are provided at an
operator station on-board the vessel.
[0049] The propelling unit 305 is arranged to be rotatable relative
to the lower surface 306 of the drive housing by a steering
arrangement 340 in order to steer the vessel. The steering
arrangement 340 is located in the drive housing comprises a
steering system with a control unit and a steering drive unit for
rotating the propelling unit about its vertical axis. The steering
drive unit can comprise an electric motor. The steering drive unit
drives a steering transmission comprising a pinon gear that drives
a gear fixed to the propelling unit 305 about the central axis X of
the vertical drive shaft 310 as indicated by the arrow A.sub.2.
[0050] The drive housing 304 in FIG. 3 further comprises a coolant
and lubricant circuit of the same type as described with reference
to FIG. 2 above.
[0051] FIG. 4 shows a schematic side view of a driveline according
to a third example. FIG. 4 shows the drive unit 403 mounted to a
transom 402 of a marine vessel (see FIG. 1). The drive unit 403
comprises an upper drive housing 404, and a lower propelling unit
405, where the propelling unit 405 is rotatably mounted to a lower
surface 406 of the drive housing 404 in order to steer the vessel.
The drive housing 404 encloses a transmission comprising a vertical
drive shaft 410 arranged to transmit drive torque from at least one
source of drive torque to a pair of forward-facing counter rotating
propellers 407 on the propelling unit 405. The transmission further
comprises a gear unit 413 operably connected to an upper end of the
vertical drive shaft 410. In FIGS. 4 and 7, one first source of
drive torque is an electric motor 411 with a vertical output shaft
412 that is operably connectable to the vertical drive shaft 410
directly through the gear unit 413. A further first source of drive
torque is a second electric motor 417 with a horizontal output
shaft 418 that is operably connectable to the vertical drive shaft
410 via the gear unit 413.
[0052] FIG. 7 shows a schematic view of the transmission for the
driveline in FIG. 4. The electric motors 411, 417 can be
disconnected from their respective shaft 412, 418 and the through
shaft comprising the vertical drive shaft 410 by demagnetizing
their respective rotors. A horizontal output shaft 320 is connected
to a second source of drive torque in the form of an inboard ICE
321 located within the hull of the vessel (see FIGS. 4 and 1).
[0053] The gear unit 413 comprises a set of bevel gears 414, 415,
416, 419 which are in constant driving contact with each other.
Each bevel gear is associated with a respective driving or driven
shaft 412, 410, 420, 418 and is switchable between a connected
state and a disconnected state for transferring torque to the
vertical drive shaft 410.
[0054] The bevel gear 416 fixed to the horizontal output shaft 420
from the ICE 421 is switchable between a driven state and a
freewheeling state by a main clutch 424 adjacent the ICE 421. The
bevel gear 419 fixed to the horizontal output shaft 418 from the
electric motor 417 is switchable between a driven state and a
freewheeling state by magnetizing and demagnetizing the rotor of
the electric motor 417. Each bevel gear 414, 415 on the vertical
drive shaft 410 is controllable between its connected and
disconnected states by a corresponding actuatable clutch 414', 415'
mounted adjacent the respective bevel gear. Switching the bevel
gears 414, 415 can be achieved by actuation or deactuation of a
suitable controllable clutch or mechanical actuator. In the
subsequent text switching is performed using wet multi-plate
clutches, or lamella clutches, hereafter referred to as "clutches".
Hence, each bevel gear 414, 415 is controllable between its
connected and disconnected states by a corresponding actuatable
clutch 414', 415' mounted adjacent the respective bevel gear.
[0055] With reference to FIG. 7, the vertical output shaft 412 of
the electric motor 411 passes directly through the gear unit 413.
The gear unit 413 comprises an upper first bevel gear 414 arranged
on the vertical output shaft 412 and a lower second bevel gear 415
arranged on the vertical drive shaft 410. The first and second
bevel gears 414, 415 are in driving connection with an intermediate
third bevel gear 416 arranged on a first horizontal output shaft
420 connected to a main clutch 424 via a main clutch 424. The first
and second bevel gears 414, 415 are further in driving connection
with an intermediate fourth bevel gear 419 arranged on a second
horizontal output shaft 418. The fourth bevel gear 419 is arranged
opposite the third bevel gear 416 coaxially with the first
horizontal output shaft 420. The second horizontal output shaft 418
is connected to an optional further source of drive torque in the
form of a second electric motor 417. The first horizontal output
shaft 420 is connected to a second source of drive torque in the
form of an inboard ICE 421 located within the hull of the vessel
(see FIG. 1). The first horizontal output shaft 420 passes through
a seal 422 in the transom 402 and is fixed in a vibration absorbing
bushing 423 supported by the ICE output shaft. A clutch 424 is
provided between the first horizontal output shaft 420 and the ICE
crankshaft to control the rotation of the first horizontal output
shaft 420. The first and second bevel gears 414, 415 are freely
rotatable about the vertical output shaft 412 and the vertical
drive shaft 410, respectively, in their disconnected state.
Similarly, the third bevel gear 416 is freely rotatable about the
first horizontal output shaft 420 in its disconnected state. The
fourth bevel gear 419 is freely rotatable about the second
horizontal output shaft 418 in its disconnected state. The upper
and lower bevel gears 414, 415 are selectably connected to their
respective shaft in order to transmit torque from the ICE 421
and/or from the second electric motor 417 to the vertical drive
shaft 410 and the propellers. In this way, the vertical drive shaft
410 can be operably connected to the first horizontal output shaft
420 which extends out of the drive housing 404 through the transom
402.
[0056] In operation, the driveline can be operated in electric mode
using the electric motor 411 rotating the output shaft 412 and the
vertical drive shaft 410 directly to drive the vessel in a forward
direction, as described for FIGS. 4 and 6. The second electric
motor 417 can be operated together with, or instead of the electric
motor 411 in electric mode. In this mode, the third bevel gear 416
is allowed to rotate freely by disconnection of the main clutch
424. This is achieved by maintaining the first bevel gear 414
disconnected. At the same time, or alternatively, the fourth bevel
gear 419 is connected to the second horizontal output shaft 418 by
actuation of the clutch 419' and the second bevel gear 415 is
connected to the vertical drive shaft 410 by actuation of the
clutch 415'. Propelling the vessel in reverse direction is achieved
by switching the direction of rotation of the electric motors 411,
417. The provision of two electric motors provides a degree of
redundancy in case one motor should malfunction.
[0057] Alternatively, the driveline can be operated in ICE mode,
wherein the rotors (not shown) of the electric motors 411, 417 are
demagnetized making the vertical output shaft 412 and the second
horizontal output shaft 418 freely rotatable. In the gear unit 413,
the first bevel gear 414 is maintained disconnected while the
second bevel gear 415 is connected to the vertical drive shaft 410
by actuation of the clutch 415'. At the same time, the third bevel
gear 416 and the first horizontal output shaft 420 are operatively
connected to the ICE 421 by actuation of the main clutch 424. The
ICE 421 can then be operated to transmit torque to the horizontal
shaft 420 and the vertical drive shaft 410 via the third bevel gear
416 and the second bevel gear 415, in order to propel the vessel in
a forward direction. In order to propel the vessel in a reverse
direction the main clutch 424 is deactuated. The second bevel gear
415 is then disconnected by deactuation of the clutch 415', while
the first bevel gear 414 is connected to the vertical output shaft
412 by actuation of the clutch 414'. Subsequently, the third bevel
gear 416 continues to be driven by the horizontal output shaft 420
by actuation of the main clutch 424. The ICE 421 can then be
operated to transmit torque to the horizontal shaft 420 and the
vertical drive shaft 410 via the third bevel gear 416 and the first
bevel gear 414.
[0058] According to a further example, the driveline can be
operated in a hybrid mode using the electric motors 411, 417 and
the ICE 421 together. In the hybrid mode, the gear unit 413 is
operated in the same way as in the ICE mode described above,
wherein the rotor of the electric motor 411 and/or the electric
motor 417 is magnetized so that the motors can be operated to drive
the vertical output shaft 412 to assist the ICE 421. The direction
of rotation of the electric motors 411, 417 is selected to
correspond with the direction of rotation of the currently
connected first or second bevel gears 414, 415 selected for forward
or reverse operation of the vessel using the ICE 421.
[0059] The propelling unit 405 contains a gearbox 408 operably
connected to a lower end of the vertical drive shaft 410, which can
be rotated as shown by the arrow A.sub.1 to drive the counter
rotating propellers 407. Gearboxes for driving counter-rotating
shafts of this type are well known and will not be described in
further detail.
[0060] The drive housing 404 further comprises a control unit and
power electronics controller (PEC) 430 for the electric motor 411.
The combined control unit and power electronics controller (PEC)
430 is also used for controlling a steering arrangement 440
described below. The outer enclosure for the drive housing 404
provides a thermal mass to absorb the heat generated by the
electric motor 411 and the PEC 430. In operation, the drive housing
404 is immersed in water and the water provides effective
convection cooling. The electric motor 411 is connected to the PEC
430, which supplies current to the electric motor 411 from an
inboard energy storage (not shown). Control means such as a
throttle and a steering means (not shown) are provided at an
operator station on-board the vessel.
[0061] The propelling unit 405 is arranged to be rotatable relative
to the lower surface 406 of the drive housing by a steering
arrangement 440 in order to steer the vessel. The steering
arrangement 440 is located in the drive housing comprises a
steering system with a control unit and a steering drive unit for
rotating the propelling unit about its vertical axis. The steering
drive unit can comprise an electric motor. The steering drive unit
drives a steering transmission comprising a pinon gear that drives
a gear fixed to the propelling unit 405 about the central axis X of
the vertical drive shaft 410 as indicated by the arrow A.sub.2.
[0062] The drive housing 404 in FIG. 4 further comprises a coolant
and lubricant circuit of the same type as described with reference
to FIG. 2 above.
[0063] It is to be understood that the present invention is not
limited to the embodiments described above and illustrated in the
drawings; rather, the skilled person will recognize that many
changes and modifications may be made within the scope of the
appended claims. For instance, the electric motor can be connected
operatively to the vertical drive shaft in different ways, such as
at a position still above but closer to the gear unit, or below the
gear unit but still inside the drive housing. The drive unit may
comprise an additional separate gear unit for the electric
motor.
* * * * *