PROPULSORS

Abstract

A propulsor for a marine vessel is described. The propulsor includes a plurality of blades extending from a rotary housing. The blades are distributed around a blade pitch circle diameter of the rotary housing. A mounting plate rotatably mounts the rotary housing to a hull of the marine vessel. A slewing bearing includes a driven ring with a driven gear that is fixed to the rotary housing and a stationary ring fixed to the mounting plate. A diameter of the slewing bearing is at least 0.4 times the blade pitch circle diameter. The propulsor includes a main electric motor with a drive shaft mechanically connected to a driving gear. The driven gear of the slewing bearing and the driving gear define a single-stage transmission gear with a transmission ratio between 5:1 and 15:1.

Claims

1. A propulsor for a marine vessel, the propulsor comprising: a rotary housing; a plurality of blades extending from the rotary housing, each blade having a respective blade axis about which it can be pivoted relative to the rotary housing, and wherein the blades are distributed around a blade pitch circle diameter of the rotary housing; a slewing bearing comprising a driven ring fixed to the rotary housing and including a driven gear, and a stationary ring adapted to be fixed to the hull of the marine vessel, wherein a diameter of the slewing bearing is at least 0.4 times the blade pitch circle diameter; a main electric motor with a drive shaft; and a driving gear mechanically connected to the drive shaft, wherein the driven gear and the driving gear define a single-stage transmission gear with a transmission ratio between 5:1 and 15:1.

2. The propulsor according to claim 1, wherein the driven ring is a radially inner ring, and the driven gear is provided on the radially inner surface of the slewing bearing.

3. The propulsor according to claim 2, wherein the driving gear is positioned radially inside the slewing bearing.

4. The propulsor according to claim 1, wherein the driven ring and the driven gear are formed as separate components that are fixed together to define a unitary driven component of the slewing bearing.

5. The propulsor according to any preceding claim 1, wherein the drive shaft is substantially parallel to the axis of rotation of the rotary housing.

6. The propulsor according to claim 1, wherein the driving gear is mechanically connected to the drive shaft by a main drivetrain that comprises a mechanism for selectively disengaging the drive shaft from the driven ring.

7. The propulsor according to claim 6, wherein the mechanism is a clutch mechanism between the drive shaft and the driving gear.

8. The propulsor according to claim 1, wherein the main electric motor is a liquid cooled permanent magnet motor.

9. The propulsor according to claim 1, further comprising a second main electric motor with a second drive shaft, and a second driving gear mechanically connected to the second drive shaft, wherein the driven gear and the second driving gear define a second single-stage transmission gear.

10. The propulsor according to claim 1, further comprising a plurality of blade actuators, each blade actuator being mechanically connected to a respective one of the blades for pivoting the blade about the blade axis.

11. The propulsor according to claim 10, wherein each blade actuator comprises an electric motor.

12. The propulsor according to claim 11, further comprising: an auxiliary electric motor for driving rotation of the rotary housing; a main power supply; and an auxiliary power supply; wherein the main electric motor is electrically connected to the main power supply and the auxiliary electric motor is electrically connected to at least one of the blade actuator electric motors and is configured to receive electrical power recovered by the at least one blade actuator electric motor a during regenerative mode.

13. The propulsor according to claim 12, wherein the auxiliary electric motor is fixed to a stationary part of the propulsor.

14. The propulsor according to claim 12, wherein the auxiliary electric motor is fixed to the rotary housing.

15. The propulsor according to claim 1, wherein the plurality of blades extend from a surface of the rotary housing, and wherein the propulsor further comprises a first empty access volume extending axially from a first access opening in the surface of the rotary housing to a second access opening adjacent the slewing bearing, the first access opening in the surface of the rotary housing being covered by a first removable access panel.

16. The propulsor according to claim 15, wherein the first empty access volume and the first and second access openings are sized and shaped to completely receive the main electric motor therethrough.

17. The propulsor according to claims 15, further comprising a mounting plate rotatably mounting the rotary housing to the hull of the marine vessel, wherein the propulsor further comprises a second empty access volume extending axially from the second access opening to a third access opening in the mounting plate, and wherein the second empty access volume and the third access opening are sized and shaped to completely receive the main electric motor therethrough

18. The propulsor according to claim 17, wherein the third access opening is covered by a second removable access panel.

19. The propulsor according to claim 1, further comprising a mounting plate rotatably mounting the rotary housing to the hull of the marine vessel, wherein the stationary ring of the slewing bearing is fixed to the mounting plate.

20. The propulsor according to claim 1, adapted to be installed into the hull of a marine vessel from below.

21. A marine vessel comprising at least one propulsor according to claim 1.

22. A method of operating a propulsor according to claim 11, the propulsor further comprising an auxiliary electric motor for driving the rotary housing, the method comprising supplying electrical power recovered by at least one of the blade actuator electric motors during a regenerative mode to the auxiliary electric motor.

23. A method of operating a propulsor according to any of claim 1 as a turbine, wherein the main electric motor is operated as a generator to generate electrical power that is fed to a main power supply electrically connected to the main electric motor.

24. A method of repairing or servicing a propulsor according to claim 16, wherein: the main electric motor is detached from the propulsor; the first access panel is removed; and the main electric motor is received completely through the second access opening, the first access volume, and the first access opening.

25. A method of repairing or servicing a propulsor according to claim 18, wherein: the main electric motor is detached from the propulsor; the first and second access panels are removed; and the main electric motor is received completely through the third access opening in the mounting plate, the second access volume, the second access opening, the first access volume, and the first access opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG. 1 is a perspective view of a propulsor according to the present invention;

[0071] FIG. 2 is a perspective view of the propulsor shown in FIG. 1 installed in the hull of a marine vessel;

[0072] FIG. 3 is a cross section view of the installed propulsor shown in FIG. 2;

[0073] FIG. 4 is a detail cross section of the installed propulsor shown in FIG. 2 showing part of the slewing bearing;

[0074] FIG. 5 is a top view of the slewing bearing and driving gears of the propulsor of FIG. 1;

[0075] FIG. 6 is a cross section view of the slewing bearing and driving gears along line A-A of FIG. 5;

[0076] FIG. 7 is a detail cross section view of the slewing bearing and driving gears shown in FIG. 5;

[0077] FIG. 8 is a perspective view of the slewing bearing and driving gears shown in FIG. 5;

[0078] FIG. 9 is a perspective view of the slewing bearing and driving gears shown in FIG. 5 with main electric motors and an auxiliary electric motor;

[0079] FIG. 10 is a schematic view of first power supply system for the propulsor according to the present invention;

[0080] FIG. 11 is a schematic view of a second power supply system for the propulsor according to the present invention;

[0081] FIG. 12 is a schematic view of the propulsor according to the present invention installed in a marine vessel;

[0082] FIGS. 13 to 15 are schematic views showing how a main electric motor can be detached and removed through the rotary housing of the propulsor according to the present invention; and

[0083] FIG. 16 is a schematic view showing how the propulsor according to the present invention can be installed from below the marine vessel.

DETAILED DESCRIPTION

[0084] Referring to FIGS. 1 to 4, a propulsor 1 for a marine vessel includes a rotary housing 2. Six blades 4a, 4b, . . . , 4f extend axially from the lower surface 2a of the rotary housing 2. Each blade 4a, 4b, . . . , 4f has a respective blade axis 6 about which it can be pivoted relative to the rotary housing 2 by a blade actuator 8. The propulsor 1 includes six blade actuators 8. Each blade actuator 8 includes an electric motor 10 and a drivetrain 12 that includes a transmission gear for pivoting the respective blade. As shown in FIG. 1, each blade 4a, 4b, . . . , 4f is mounted in a respective blade module housing 36a, 36b, . . . , 36e, 36f that extends radially outwardly from a main body.

[0085] The blades 4a, 4b, . . . , 4f are distributed around a blade pitch circle diameter D1 of the rotary housing 2i.e., the diameter of the rotary housing that passes through the blade axes 6.

[0086] The propulsor 1 includes a mounting plate 14 for mounting the propulsor to the hull of the marine vessel. A slewing bearing 16 is used to mount the rotary housing 2 to the mounting plate 14 so that it can rotate freely.

[0087] FIGS. 2 to 4 show the propulsor 1 mounted within an annular collar H that forms a structural part of the hull of the marine vessel. The annular collar includes an upper annular surface H1, a first inner cylindrical surface H2, an inner frustoconical surface H3, and a second inner cylindrical surface H4. The inner surface H2 is adjacent the slewing bearing 16 and the inner surfaces H3 and H4 define an inner profile of the collar that conforms generally to the outer profile of the rotary housing 2. The rotary housing 2 and the inner surfaces H3 and H4 of the collar are separated by a gap G that allows the rotary housing to rotate freely. The gap G has an open end at the lower surface 2a of the rotary housing 2 and a closed end adjacent the slewing bearing 16. One or more static or dynamic seals (not shown) can be provided at the closed end to provide a watertight seal and prevent the ingress of water into the interior of the rotary housing 2 past the slewing bearing 16.

[0088] The mounting plate 14 is fixed to the collar H by means of an intermediate fixing structure (not shown) that is positioned between the lower surface of the mounting plate and the upper annular surface H1 of the collar.

[0089] As shown in more detail in FIGS. 5 to 9, the slewing bearing 16 includes a driven ring 18 that is fixed to the rotary housing 2, a stationary ring 20 that is fixed to the mounting plate 14, and a driven gear 22 that is fixed to the driven ring 18. In an alternative arrangement, the stationary ring 20 can be fixed directed to the hull of the marine vessel, e.g., to the inner surface H2 of the collar.

[0090] The driven ring 18 defines a seat for receiving and locating the driven gear 22. The driven ring 18 includes a plurality of openings 18a distributed around a driven ring pitch circle diameter. The driven gear 22 is located in the seat defined by an annular surface 18b and a cylindrical surface 18c of the driven ring 18. The driven gear 22 includes a plurality of openings 22a distributed around a driven gear pitch circle diameter, which openings 22a are aligned with the openings 18a in the driven ring 18. The driven ring 18 and the driven gear 22 are fixed together and to the rotary housing 2 by a plurality of bolts (not shown) that are received in the aligned openings 18a and 22a, and also in corresponding aligned openings 2b in the rotary housing. A plurality of teeth 22b are formed on the radially inner surface of the driven gear 22.

[0091] The driven ring 18 and the driven gear 22 together define a unitary driven component of the slewing bearing 16 that is used to rotate the rotary housing 2 relative to the mounting plate 14. In an alternative arrangement, the driving gear can be formed as an integral part of the driving ring.

[0092] The stationary ring 20 includes a plurality of openings 20a distributed around a stationary ring pitch circle diameter. The stationary ring 20 is fixed to the mounting plate 14 by a plurality of bolts (not shown) that are received in the openings 20a and also in corresponding aligned openings in the mounting plate.

[0093] The stationary ring 20 is located radially outside the driven ring 18 and the driven gear 22.

[0094] A plurality of rolling elements (not shown) are positioned between the driven and stationary rings 18 and 20.

[0095] A diameter D2 of the slewing bearing is at least 0.4 times the blade pitch circle diameter D1. The diameter D2 of the slewing bearing is preferably less than 0.8 times the blade pitch circle diameter. In this example, the diameter D2 is the radially outer diameter of the driven gear 22i.e., the interface between the driven gear and the driven ring 18. But it will be readily understood that the diameter D2 could also be: [0096] the radially inner diameter of the driven ring, [0097] the radially outer diameter of the driven ring, [0098] the driven ring pitch circle diameter, [0099] the radially inner diameter of the driven gear, [0100] the driven gear pitch circle diameter, [0101] a diameter of the rolling elements between the driven and stationary rings, [0102] the radially inner diameter of the stationary ring, [0103] the radially outer diameter of the stationary ring, or [0104] the stationary ring pitch circle diameter, for example.

[0105] In this example, the blade pitch circle diameter D1 is about 10 m and the diameter D2 is about 6.7 m, which is within the preferred range of about 4 m to about 8 m.

[0106] Two driving gears 24a and 24b (or pinion gears) are located radially inside the driven gear 22. The first driving gear 24a is mechanically connected to a drive shaft 26a of a first main electric motor 28a. The second driving gear 24b is mechanically connected to a drive shaft 26b of a second main electric motor 28b.

[0107] The driven gear 22 and the first driving gear 24a define a first single-stage transmission gear 30a. The driven gear 22 and the second driving gear 24b define a second single-stage transmission gear 30b in parallel with the first single-stage transmission gear 30a.

[0108] In this example, the transmission ratio of the first and second single-stage transmission gears is 10:1. Each of the first and second driving gears 24a and 24b has twelve teeth and the driven gear 22 has one hundred and twenty teeth around its radially inner surface. If the transmission ratio is 10:1 it means that each driving gear 24a and 24b will rotate about ten times for each rotation of the driven ring 22 of the slewing bearing relative to the stationary ring 20 that is fixed to the mounting plate 14.

[0109] In this example, the rotary housing 2 may be driven to rotate at a rotational speed of about 15 rpm when operating in a trochoidal mode and at a rotational speed of about 30 rpm when operating in a cycloidal mode. The drive shafts 26a and 26b of the first and second main electric motors 28a and 28b, and the first and second driving gears 24a and 24b, may rotate at a rotational speed of about 150 rpm and about 300 rpm depending on the operating mode.

[0110] The first and second main electric motors 28a and 28b are liquid cooled permanent magnet motors.

[0111] The first and second main electric motors 28a and 28b are mounted on the mounting plate 14. More particularly, each first and second electric motor 28a and 28b has an outer housing or casing that is fixed to the upper surface of the mounting plate 14. Each drive shaft 26a and 26b extends through a respective opening in the mounting plate 14 because the first and second main electric motors 28a and 28b and the first and second driving gears 24a and 24b are positioned on opposite sides of the mounting plate.

[0112] The drive shafts 26a and 26b of the first and second main electric motors 28a and 28b are aligned substantially parallel to the axis of rotation of the rotary housing 2.

[0113] The first and second main electric motors 28a and 28b receive electrical power from a main power supply. The main power supply can be electrically connected to, or be part of, the power distribution system of the marine vessel. FIG. 10 shows a first power supply system 100 for the propulsor. The rotating part of the first power supply system is indicated generally by the dashed box 102 and the stationary part by the dashed box 104. Four blade actuator motors 10a, 10b, . . . , 10d are located in the rotary housing 2 and are therefore shown in the rotating part. Each blade actuator motor 10a, 10b, . . . , 10d is mechanically connected to a respective inverter 106a, 106b, . . . , 106d by means of a slip ring 108a, 108b, . . . , 108d. The inverters 106a, 106b, . . . , 106d are electrically connected to a rectifier 110 by a DC link 112. The rectifier 110 is electrically connected to the power distribution system 114 of the marine vessel. The first main electric motor 28a is also electrically connected to the power distribution system 114 of the main vessel by means of a main power converter or variable speed drive (VSD) 116. Although not shown, it will be readily understood that the second main electric motor 28b can be electrically connected to the power distribution system in the similar manner. The main power converter or VSD 116 is part of a main power supply.

[0114] The blade actuator electric motors 10 can sometimes experience a regenerative mode during operation of the propulsor 1. Electrical power generated by the blade actuator electric motors 10 during this regenerative mode can be supplied to an auxiliary electric motor 32 by an auxiliary power supply. FIG. 11 shows a second power supply system 200 for the propulsor 1. The rotating part of the power supply system is indicated generally by the dashed box 202 and the stationary part by the dashed box 204. Four blade actuator motors 10a, 10b, . . . , 10d are shown in the rotating part. Each blade actuator motor 10a, 10b, . . . , 10d is mechanically connected to a respective inverter 206a, 206b, . . . , 206d. The inverters 206a, 206b, . . . , 206d are electrically connected to a rectifier 208 by means of a slip ring 210. The rectifier 208 is electrically connected to the power distribution system 212 of the marine vessel. The auxiliary electric motor 32 is in the stationary part and is also electrically connected to the DC link 214 by means of an auxiliary power converter or VSD 216 which forms part of the auxiliary power supply. The first main electric motor 28a is electrically connected to the power distribution system 212 of the marine vessel by means of a main power converter or VSD 218. Although not shown, it will be readily understood that the second main electric motor 28b can be electrically connected to the power distribution system in the similar manner. The main power converter or VSD 218 is part of a main power supply.

[0115] As shown in FIG. 9, a third (or auxiliary) driving gear 24c is located radially inside the driven gear 22. The third driving gear 24c is mechanically connected to a drive shaft 34 of the auxiliary electric motor 32. The driven gear 22 and the third driving gear 24c define a third single-stage transmission gear 30c. Although in FIG. 9 the auxiliary electric motor 32 is positioned below the third driving gear 24c, this is only so that the third single-stage transmission gear 30c is shown clearly. In practice, the auxiliary electric motor 32 is mounted on a stationary part of the propulsor such as the mounting plate 14 and would therefore be positioned above the third driving gear 24c in a similar manner to the main electric motors. In an alternative arrangement, which is not shown, the auxiliary electric motor is fixed to the rotary housing and the third driving gear is engaged with an auxiliary stationary gear that is fixed to a stationary part of the propulsor.

[0116] Any electrical energy that is recovered by the blade actuator electric motors 10 during a regenerative mode of operating can be converted to mechanical energy which can be used to help rotate the rotary housing, e.g., to drive the driven ring 18 of the slewing bearing 16. In particular, as shown in FIG. 11, any electrical power generated by one or more of the blade actuator electric motors 10a, 10b, . . . , 10d can be supplied to the DC link 214 and then to the auxiliary electric motor 32 by means of the auxiliary power converter or VSD 216. The electrical power supplied to the auxiliary electric motor 32 is used to rotate the third driving gear 24c to drive the driven ring 18 of the slewing bearing 16. In the alternative arrangement mentioned above, the electrical power supplied to the auxiliary electric motor is used to rotate the third driving gear which rotates the auxiliary electric motor, which is fixed to the rotary housing, relative to the auxiliary stationary gear.

[0117] In an alternative arrangement, any electrical power generated by the blade actuator electric motors 10 can be fed back into the main power supply that is .

[0118] The mounting plate 14 includes an upper main access panel 38 and two smaller access panels 40a and 40b. The upper main access panel 38 covers an upper access opening 42 in the mounting plate 14 that is sized and shaped to completely receive the main electric motors 28a and 28b. The smaller access panels 40a and 40b cover access openings that allow an engineer to access the interior of the rotary housing 2 from inside the marine vessel and are located radially inside slewing bearing 16.

[0119] The lower surface 2a of the rotary housing 2 includes a lower main access panel 44. The lower main access panel 44 covers a lower access opening 46 in the rotary housing 2 that is also sized and shaped to completely receive the main electric motors 28a and 28b. A watertight seal is maintained between the lower main access panel 44 and the rotary housing 2 to prevent ingress of water into the interior of the rotary housing.

[0120] The central part of the interior of the rotary housing 2 is devoid of any components or equipment to create an empty access volume 48 that extends axially between the upper and lower access openings 42 and 46 that are covered by the upper and lower main access panels 38 and 44. The empty access volume 48 also includes an intermediate access opening 50 that is defined by the slewing bearing 16 and through which the interior of the rotary housing 2 can be accessed from above. The empty access volume 48 can therefore be considered to include a lower access volume 48a that extends between the lower access opening 46 in the lower surface 2a of the rotary housing 2 and the intermediate access opening 50, and an upper access volume 48b that extends between the intermediate access opening and the upper access opening 42 in the mounting plate 14.

[0121] FIGS. 13 to 15 show how one of the main electric motors 28b can be removed through the propulsor so that a replacement main electric motor can be installed in its place without the need to remove the whole propulsor. In particular, FIG. 13 shows the upper main access panel 38 removed and the main electric motor 28b detached from the mounting plate 14 and from any associated equipment (e.g., cooling system or auxiliaries). FIG. 14 shows the lower main access panel 44 removed from the lower surface 2a of the rotary housing. FIG. 15 shows how the detached main electric motor 28b can be lowered by winch cables through the upper and lower access openings 42 and 46 in the mounting plate 14 and the lower surface 2a of the rotary housing as indicated by the block arrows. The main electric motor 28b will pass through the intermediate access opening 50 adjacent the slewing bearing 16 and through the empty access volume 48 without obstruction. A replacement main electric motor can be installed through the propulsor in a similar manner, i.e., lifted by winch cables through the lower and upper access openings 46 and 42 in the lower surface 2a of the rotary housing 2 and the mounting plate 14, before being attached to the mounting plate.

[0122] FIG. 16 shows how the propulsor is adapted to be installed into the collar H from below the marine vessel. In particular, FIG. 16 shows an intermediate installation stage where the mounting plate 14 has been at least partly disassembled, passed through the opening in the collar H, and reassembled and fixed to the collar. The main electric motors 28a and 28b have also been attached to the mounting plate 14. The rotary housing 2 with its internal components and equipment can then be installed into the collar from below as indicated by the block arrow. The driven ring 18 and the driven gear 22 of the slewing bearing 16 are already fixed to the rotary housing 2. Once the rotary housing 2 is installed into the collar H, the stationary ring 20 is fixed to the mounting plate 14 (or directly to the hull) and the blades can be installed to the blade modules.