EP4588779A1

EP4588779A1 - Marine propulsion device and marine hybrid drive

Info

Publication number: EP4588779A1
Application number: EP24152884.3A
Authority: EP
Inventors: Michele Zottele; Mattia Caracristi; Andrea Pellegrinetti
Original assignee: ZF Friedrichshafen AG; ZF Padova SRL
Current assignee: ZF Friedrichshafen AG; ZF Padova SRL
Priority date: 2024-01-19
Filing date: 2024-01-19
Publication date: 2025-07-23
Anticipated expiration: 2044-01-19
Also published as: EP4588779C0; EP4588779B1

Abstract

The present invention relates to a marine propulsion device (1) comprising a first input shaft (2) to be connected to a combustion engine (3). The marine propulsion device (1) further comprising an upper bevel gear set (4) to transmit propulsion power from the first input shaft (2) via a vertical shaft (5) and via a lower bevel gear set (6) to a propeller shaft (7). The upper bevel gear set (4) comprises at least one bevel pinion (8, 9) and a crown gear (10) which are meshing with each other. The at least one bevel pinion (8, 9) is arranged coaxial to the first input shaft (2) and the crown gear (10) is arranged coaxial to the vertical shaft (5).

The marine propulsion device (1) further comprising a second input shaft (11) to be connected to an electric machine (12). The second input shaft (11) is arranged coaxially to the first input shaft (2) and permanently connected to the crown gear (10) The marine propulsion device (1) comprises an output clutch (13) which is arranged between the crown gear (10) and the vertical shaft (5).

The invention further relates to a marine hybrid drive (100) with such a marine hybrid propulsion device (1).

Description

The present invention relates to a marine propulsion device, particularly to a Marine propulsion device for a Z-drive or a pod drive, and a corresponding marine hybrid drive.
Conventional marine drives comprise a combustion engine, which can be mounted inside a hull of a ship. The power from the combustion engine is transmitted via a drive train with shafts and device elements to one or two propellers, which are fixed to a propeller shaft. Typically a forward and a reverse clutch are arranged in the drive train, to realize forward and reverse rotation directions of the propeller shaft.
In recent years there is an increasing demand for marine propulsion devices with electric drive machines for environmental and efficiency reasons. For these reasons several marine propulsion devices have been proposed in form of hybrid drives comprising a combustion engine and an electric machine for the propulsion of water vessels.
In the US 2014/0187107 A1 a hybrid marine propulsion device with a combustion engine and an electric motor has been disclosed. The hybrid marine propulsion device includes a propulsion pod that houses a propulsor, which is configured to rotate about a first horizontal axis and to be driven by a vertical shaft. The drive system also includes a gearbox connected to drive the vertical shaft, the horizontally arranged combustion engine connected to drive the gearbox via a horizontal shaft, and an electric motor connected to drive the vertical shaft via the gearbox or directly.
The purpose of the present invention is to provide an improved marine propulsion device and a marine hybrid drive with a broad range of applicability and highly efficient operation.
This purpose is achieved by a marine propulsion device according to claim 1 and by a marine hybrid drive according to claim 9. Further embodiments are claimed in dependent claims.
The present invention provides a marine propulsion device comprising a first input shaft to be connected to a combustion engine and an upper bevel gear set to transmit propulsion power from the first input shaft via a vertical shaft and via a lower bevel gear set to a propeller shaft. Typically such an arrangement is used for Z-drives, thrusters, and pod-drives with inboard engines. The terms horizontal and vertical refer to a marine propulsion device operably installed in a water vessel in calm sea, wherein the vertical and horizontal directions are to be understood as approximate directions. Deviations of a few degrees from an exact vertical or horizontal direction shall still be considered as being vertical respectively horizontal.
The upper bevel gear set comprises at least one bevel pinion and a crown gear which are meshing with each other. The at least one bevel pinion is arranged coaxial to the first input shaft and the crown gear is arranged coaxial to the vertical shaft. The crown gear can be connected to and disconnected from the vertical shaft by means of an output clutch.
The marine propulsion device further comprising a second input shaft, which is connected to an electric machine. The marine propulsion device can be driven by the combustion engine and/or by the electric machine in different operating modes. The second input shaft is arranged coaxially to the first input shaft and permanently connected to the crown gear via the first bevel pinion.
The output clutch is arranged between the crown gear and the vertical shaft to be able to disconnect the transmission of driving power between the crown gear and the vertical shaft. Said disconnection is particularly useful when the electric machine is operated as a generator and driven by the combustion engine. In this operating mode, the rotation of the propeller can be avoided by disengaging the output clutch. Hence, the power from the combustion engine is solely used for generating electric energy by the electric machine.
According to one embodiment, a hub of the crown gear is arranged to permanently connect the crown gear to an output clutch input portion, and an upper end of the vertical shaft is supported in the hub. Said hub can be an integral part of the crown gear or the hub can be a sleeve which is rigidly connected to the toothed section of the crown gear. With such an embodiment, a particularly reliable and compact design can be achieved.
The output clutch can be a positive or a negative clutch. A positive clutch is normally open, i.e. disengaged. The open position of a positive clutch can be maintained by any kind of spring or elastic element. A positive clutch can be closed, i.e. engaged, by overriding the force of the spring by an external effect. A typical positive clutch is a pressure actuated clutch. Applying the correct pressure to a pressure actuated clutch will engage the clutch and torque can be transmitted by the clutch.
Particularly for embodiments, wherein the output clutch is a pressure actuated positive clutch, an oil pump can be arranged for the actuation of the output clutch. Said oil pump preferably is an external electric oil pump to enable the actuation of the output clutch during solely electric propulsion by means of the electric machine.
A negative clutch is normally closed, i.e. engaged, so that it will transmit torque from an input side to an output side in its normal status. In a negative clutch the force of at least one spring maintains the closed status. The at least one spring maintains the negative clutch closed and provides the correct force, for example to the disks of a multi-disk clutch, to transmit a nominal torque of the clutch. A negative clutch can be opened by overriding the force of the spring by an external effect. Typical negative clutches are pressure operated multi-disk clutches or electromagnetic clutches. In one kind of an electromagnetic negative clutch the torque is transmitted via form-fitting elements like a splined connection in the closed status, while springs with a comparatively low force maintain the clutch closed. By applying electric current on an electromagnetic actuator the clutch can be opened and maintained in the open status as long as the electric current is applied.
The underwater housing of such a marine propulsion device can be designed with a more streamlined outer outline because the output clutch can be mounted together with the upper bevel gear set in a housing inside the hull. This way the drag in the water can be reduced.
A preferred embodiment comprises a first bevel pinion and a second bevel pinion, wherein the first bevel pinion can be connected to the first input shaft by a first engine clutch, and wherein the second bevel pinion can be connected to the first input shaft by a second engine clutch. The first engine clutch and the second engine clutch are there to transmit driving power from the first input shaft to the vertical shaft selectively in a forward or reverse direction by engaging the first engine clutch or the second engine clutch. This is a common configuration for a pod-drive which is driven by a combustion engine whose crankshaft is driven in one rotational direction only. The driving power will be further transmitted via the upper bevel gear set, the vertical shaft, the lower bevel gear set and the propeller shaft to a propeller and effect the propulsion of the water vessel in a forward or reverse direction. The driving power of the combustion engine can therefore be transmitted selectively in a forward or reverse direction by engaging either the first engine clutch or the second engine clutch. Engaging the first engine clutch may effect a rotation of the vertical shaft in a forward direction and an engagement of the second engine clutch may effect a rotation of the vertical shaft in a reverse direction. However, the rotating directions can also be related vice versa.
The first engine clutch in this embodiment comprises a first clutch input part and a first clutch output part. The second engine clutch comprises a second clutch input part and a second clutch output part. Both clutches are preferably pressure actuated multi-disk clutches. Hence, the first and second input parts and output parts can be disk carriers. The first and second clutch input parts can be outer disk carriers and the first and second clutch output parts can be inner disk carriers or vice versa.
In an embodiment the first input shaft is permanently connected to the first clutch input part and the second clutch input part, while the first clutch output part and the second clutch output part are permanently connected to the vertical shaft. The second input shaft is permanently connected to the second clutch output part in one embodiment. This means, that the electric machine is connected to the vertical shaft and can drive the vertical shaft and the propeller shaft independent from the status of the first and second engine clutch. In other words, the driving power from the electric machine can be transmitted directly from the second input shaft via the second clutch output part and to the vertical shaft. There is no power flow through the first or the second engine clutch, when the marine hybrid drive is driven only electrically, i.e. solely by the electric machine.
The word connected in the context of this document means that a driving power in form of torque and rotation can be transmitted via the corresponding connection. A connection can or cannot be permanent. Permanently connected means, that the connection cannot be disconnected during operation. Permanent connections for example can be rigid connections, like flanged, splined, or welded connections. Connection via a set of gears which cannot be disconnected during operation are permanent connections, as well. Non-permanent connections include some kind of clutch which can be engaged for power device and disengaged to cut off the power device during operation.
For example in case of a failure in the pressure supply to the pressure actuated first and second engine clutch, the power from the first input shaft cannot be transmitted to the vertical shaft. The present invention enables to drive the vertical shaft in such a situation solely by the electric machine via the second input shaft when the output clutch is engaged. This way, the electric machine provides for a backup solution in case of failure or lack of the main propulsion from the combustion engine or a failure of the engine clutches. Hence, the reliability of the marine hybrid device and the corresponding marine hybrid drive is increased.
The electric machine alone can drive the vertical shaft and the propeller shaft in a forward or in a reverse direction when the first engine clutch and the second engine clutch are disengaged. This way a solely electric cruising is enabled, especially to cruise protected areas with low noise and zero emission. It is possible to operate the marine hybrid drive in an Eco-mode, wherein the combustion engine only runs when power requirements exceed the renewable sources and available battery capacity.
Another mode of operation is a booster-mode, which adds the output power of the electric machine to the combustion engine power output. This is possible during operation in full power and during intermediate power output phases. During intermediate power output phases it is possible to get the best performance, efficiency and fuel saving by operating the combustion engine in the most efficient rpm range and using the electric machine for small accelerations or changes in speed.
Another possible operation mode is a generating mode. Therefore the electric machine is operated in a mode to generate electric energy for charging a battery or to provide electric energy to other consumers on the water vessel. This can be established either while the combustion engine is driving the propeller shaft at the same time or when the propeller is not being driven by the combustion engine. If the combustion engine shall drive the propeller and the electric machine for generating electric energy at the same time, the output clutch and the first or the second engine clutch must be engaged. To operate the marine hybrid drive in a generating mode, wherein the electric machine is driven by the combustion engine and the propeller is not rotating, the first or the second engine clutch must be engaged, and the output clutch must be disengaged.
A further electric generating mode can be established, if the marine propulsion device is installed on a sailboat, the vertical shaft can rotate for the effect of the propeller and effect a so-called hydrogeneration during sailing, when the output clutch is engaged. Such a further generating mode requires that a sailboat speed is greater than 3-4 knots to comport a rotation of the propeller for the drag effect at the propeller.
A further aspect of the current invention is a compact design of the marine propulsion device considering the restricted space inside a hull of a ship or boat. In one embodiment the second input shaft is directly connected to a bevel gear of the upper bevel gear set by means of a splined connection. The direct connection by means of a splined connection allows for a compact design and a solid and reliable connection.
In a further embodiment the second input shaft is a hollow shaft, and one end of the first input shaft is supported in the second input shaft. This means, that at least a part of the first input shaft can extend into or through the second input shaft, which is a hollow shaft. Such an embodiment provides a very compact and solid design. The first input shaft can be supported in a housing of the upper bevel gear set by a first bearing. An engine connection can be arranged at a first end of the first input shaft and a second bearing can be arranged at a second end of the first input shaft to support the first input shaft inside the second input shaft. Said engine connection can be a flanged connection, a splined connection, or a coupling, just to name a few examples. A third bearing can be arranged to support the second input shaft in the housing. The first, second and third bearings can be sliding or rolling bearings.
Eventually the upper bevel gear set and the output clutch may be enclosed together in one housing. Said housing can also enclose the first and second engine clutches. The housing can be installed inside a hull of a water vessel, whereas the lower bevel gear set is mounted in an underwater housing which has a relatively small and streamlined outer form and causes very little drag in the water.
The invention further relates to a marine hybrid drive comprising a combustion engine and a marine propulsion device as described above. Such a marine propulsion device provides an optimal integration between the combustion engine and the electric machine with high flexibility in view of different operating modes. The described design allows the installation of the electric motor with a direct engagement to the coaxial second input shaft in a very limited space of an engine room of a water vessel.
Depending on the requirements of the specific application, the electric machine may have a nominal power in the range between 15 and 100 Kilowatt. The electric machine can be a low voltage machine to be operated for example on 48 Volt or it can be a high voltage machine to be operated in a range between 360 and 400 Volt. The proposed marine hybrid drive can be used for thrusters, pod drives or saildrives, just to name a few exemplary applications.
The invention will be further and more particularly described in the following, by way of example only, and with reference to the accompanying figures.

Fig. 1: shows a marine hybrid drive with a combustion engine, with an electric machine and with a marine hybrid propulsion device according to the invention in a schematic drawing and
Fig. 2: shows a sectional view of a marine propulsion device according to the invention.

The marine hybrid drive 100 as shown in Fig. 1 comprises a marine propulsion device 1, a combustion engine 3 as a first prime mover and an electric machine 12 as a second prime mover. The marine propulsion device 1 is mounted in an engine room inside a hull 101 of a water vessel 102.
The marine propulsion device 1 comprising a first input shaft 2 which is permanently connected to a crank shaft 31 of the combustion engine 3 and a second input shaft 11 which is permanently connected to a motor shaft 32 of the electric machine 12. The motor shaft 32 of the electric machine 12 runs coaxial to the first input shaft 2 and to the second input shaft 11. The electric machine 12 is installed in horizontal position in the back of the marine hybrid drive 100, i.e. on the opposite side of the marine hybrid device 1 with regard to the combustion engine 3. The electric machine 12 is supported by an intermediate casing 34, which is fastened to a housing 26. The second input shaft 11 extends at least partially in the intermediate casing 34.
The marine propulsion device further comprises an upper bevel gear set 4 to transmit propulsion power from the first input shaft 2 via a vertical shaft 5 and via a lower bevel gear set 6 to a propeller shaft 7. The upper bevel gear set 4 comprises two bevel pinions 8 and 9 and a crown gear 10. Each of the two bevel pinions 8 and 9 is permanently meshing with the crown gear 10. Both bevel pinions 8 and 9 are arranged coaxial to the first input shaft 2. The first bevel pinion 8 can be drivingly connected to the first input shaft 2 by a first engine clutch 19 and the second bevel pinion 9 can be connected to the first input shaft 2 by a second engine clutch 22.
The vertical shaft 5 runs in a vertical direction and transmits the driving power from the upper bevel gear set 4 via the output clutch 13 to the lower bevel gear set 6, which is located inside a POD underneath the hull 101. The vertical shaft 5 is connected to the output side of the output clutch 13. The lower bevel gear set 6 drives a propeller shaft 7 with a propeller 33 fastened to its trailing end. The propeller shaft 7 is oriented in a horizontal direction.
The first engine clutch 19 and the second engine clutch 22 are arranged inside the housing 26 for selectively transmitting the driving power from the first input shaft 2 in a forward or reverse direction. The forward direction can be selected by engaging the first engine clutch 19, while the second engine clutch 22 is disengaged. The reverse direction can be selected by engaging the second engine clutch 22, while the first engine clutch 19 is disengaged. The first engine clutch 19 comprises a first clutch input part 20 and a first clutch output part 21. The second engine clutch 22 comprises a second clutch input part 23 and a second clutch output part 24. Both engine clutches 19 and 22 are multi-disk clutches. The clutch input parts 20 and 23 of both engine clutches 19 and 22 are outer disk carriers. The clutch output parts 21 and 24 are both inner disk carriers.
The first input shaft 2 is permanently connected to the first clutch input part 20 and to the second clutch input part 23, i.e. to both outer disk carriers. The second clutch output part 24 is rigidly connected to the second input shaft 11. In this embodiment, the second input shaft 11 and with it the motor shaft 32 of the electric machine 12 are permanently connected to the crown gear 10 via the second bevel pinion 9. Said permanent connection between the electric machine 12 and the crown gear 10 allows for forward and reverse maneuvers without any interaction with the first and second engine clutch 19, 22. The electric machine 12 can be operated in the requested rotational direction to propel the water vessel 102 forward or reverse. With other words, the electric machine 12 can be operated independently from the drive train of the combustion engine 3, when the engine clutches 19 and 22 are disengaged. The electric machine 12 may be controlled by a separate control system without interaction or interfaces with a control system of the combustion engine 3.
The first clutch output part 21 is rigidly connected to the first bevel pinion 8, and the second clutch output part 24 is rigidly connected to the second bevel pinion 9.
Hence, the first clutch output part 21 and the second clutch output part 24 are both permanently connected to crown gear 20, which is constantly meshing with the first and the second bevel pinion 8, 9.
At a first end of the first input shaft 2 there is an engine connection 28 arranged to connect the first input shaft 2 to the crank shaft 31 of the combustion engine 3. The connection between the crank shaft 31 and the first input shaft 2 may include further elements, like a flywheel, an elastic coupling and/or a torsional damper, in some embodiments.
Fig. 2 shows a section from a part of the marine propulsion device 1 with the electric machine 12 in a more detailed section of the upper bevel gear set 4 and the output clutch 13. The same components are indicated with the same referals as in Fig. 1.
A hub 14 of the crown gear 10 is arranged to permanently connect the crown gear 10 to an output clutch input portion 16. The output clutch 13 is a pressure actuated multi-disk clutch. The output clutch input portion 16 comprises an inner disk carrier. An output clutch output portion 17 in form of an outer disk carrier is rigidly connected to the vertical shaft 5. The upper end 18 of the vertical shaft 5 is supported in the hub 14. The hub 14 extends in vertical direction to form an essentially cylindrical extension. Such a hub 14 can be a solid support for a bearing arrangement 35 to support the crown gear 10 in the housing 26 of the upper bevel gear set 4. A vertical shaft bearing 15 is arranged at the lower end of the hub 14. The upper end 18 of the vertical shaft 5 is rotatable supported in the crown gear 10 by the vertical shaft bearing 15.
The engine connection 28 is done in form of a spline at the first end of the first input shaft 2. A first end of the first input shaft 2 is supported in the housing 26 by a first bearing 27. The second end of the first input shaft 2 extends into the central bore of the second input shaft 11, which is a hollow shaft. At the second end of the first input shaft 2, there is a second bearing 29 arranged to support the first input shaft 2 inside the second input shaft 11. The second bearing 29 in this embodiment is a roller bearing. It is arranged between the central first input shaft 2 and the hollow second input shaft 11. The second input shaft 11 is supported in the housing 26 by means of a third bearing 30, which is a double angular ball bearing. The first bearing 27 and the second bearing 29 are tapered roller bearings, which are arranged in a X-type application to appropriately support the first input shaft 2 in the housing 26. The second input shaft 11 is connected to the motor shaft 32 of the electric machine 12 by means of a splined connection 25. The vertical shaft 5 with crown gear 20 is supported in the housing 26 by a bearing arrangement 35 comprising two tapered roller bearings in an O-type application.

Referals

1: marine propulsion device
2: first input shaft
3: combustion engine
4: upper bevel gear set
5: vertical shaft
6: lower bevel gear set
7: propeller shaft
8: bevel pinion
9: bevel pinion
10: crown gear
11: second input shaft
12: electric machine
13: output clutch
14: hub
15: vertical shaft bearing
16: output clutch input portion
17: output clutch output portion
18: upper end
19: first engine clutch
20: first clutch input part
21: first clutch output part
22: second engine clutch
23: second clutch input part
24: second clutch output part
25: splined connection
26: housing
27: first bearing
28: engine connection
29: second bearing
30: third bearing
31: crank shaft
32: motor shaft
33: propeller
34: intermediate casing
35: bearing arrangement
100: marine hybrid drive
101: hull
102: water vessel

Claims

Marine propulsion device (1) comprising a first input shaft (2) to be connected to a combustion engine (3), the marine propulsion device (1) further comprising an upper bevel gear set (4) to transmit propulsion power from the first input shaft (2) via a vertical shaft (5) and via a lower bevel gear set (6) to a propeller shaft (7),
wherein the upper bevel gear set (4) comprises at least one bevel pinion (8, 9) and a crown gear (10) which are meshing with each other, wherein the at least one bevel pinion (8, 9) is arranged coaxial to the first input shaft (2) and the crown gear (10) is arranged coaxial to the vertical shaft (5),

the marine propulsion device (1) further comprising a second input shaft (11) to be connected to an electric machine (12), wherein the second input shaft (11) is arranged coaxially to the first input shaft (2), wherein the second input shaft (11) is permanently connected to the crown gear (10), and

wherein the marine propulsion device (1) comprises an output clutch (13) which is arranged between the crown gear (10) and the vertical shaft (5).
Marine propulsion device (1) according to claim 1, wherein a hub (14) of the crown gear (10) is arranged to permanently connect the crown gear (10) to an output clutch input portion (16), and wherein an upper end (18) of the vertical shaft (5) is supported in the hub (14).
Marine propulsion device (1) according to claim 1 or 2, comprising a first engine clutch (19) and a second engine clutch (22) to transmit driving power from the first input shaft (2) to the vertical shaft (5) selectively in a forward or reverse direction by engaging the first engine clutch (19) or the second engine clutch (22), wherein the first engine clutch (19) comprises a first clutch input part (20) and a first clutch output part (21), wherein the second engine clutch (22) comprises a second clutch input part (23) and a second clutch output part (24),
wherein the first input shaft (2) is permanently connected to the first clutch input part (20) and the second clutch input part (23),

wherein the second input shaft (11) is permanently connected to the second clutch output part (24),

and wherein the first clutch output part (21) and the second clutch output part (24) are permanently connected to the crown gear (10).
Marine propulsion device (1) according to claim 3, wherein the first clutch output part (21) is rigidly connected to a first bevel pinion (8), and wherein the second clutch output part (24) is rigidly connected to a second bevel pinion (9).
Marine propulsion device (1) according to one of the preceding claims, wherein the second input shaft (11) is directly connected to the second bevel pinion (9) by means of a splined connection (25).
Marine propulsion device (1) according to one of the preceding claims, wherein the second input shaft (11) is a hollow shaft, and wherein one end of the first input shaft (2) is supported in the second input shaft (11).
Marine propulsion device (1) according to one of the preceding claims, wherein the first input shaft (2) is supported in a housing (26) by a first bearing (27), wherein an engine connection (28) is arranged at a first end of the first input shaft (2), wherein a second bearing (29) is arranged at a second end of the first input shaft (2) to support the first input shaft (2) inside the second input shaft (11), and wherein a third bearing (30) is arranged to support the second input shaft (11) in the housing (26).
Marine propulsion device (1) according to one of the preceding claims, wherein the upper bevel gear set (4) and the output clutch (11) are enclosed in a housing (26).
Marine hybrid drive (100) comprising a combustion engine (3), an electric machine (12) and a marine propulsion device (1) according to one of the preceding claims.