Propeller drive assembly

Abstract

A propeller drive assembly for transferring a torque between an engine and at least one propeller of a water surface vessel includes a plurality of lubrication clients. The propeller drive assembly includes a first lubrication system arranged to house a first lubricant, dedicated for lubrication of at least one first of the lubrication clients, and a second lubrication system arranged to house a second lubricant, dedicated for lubrication of at least one second of the lubrication clients, the at least one second lubrication client includes a seal arranged to seal the second lubrication system from a body of water surrounding at least a portion of the propeller drive assembly, the second lubrication system being arranged to transport the second lubricant to the seal.

Claims

1. A propeller drive assembly for transferring a torque between an engine and at least one propeller of a water surface vessel, the propeller drive assembly comprising a propeller shaft for supporting a propeller and a plurality of lubrication clients, wherein the propeller drive assembly comprises a first lubrication system arranged to house a first lubricant, dedicated for lubrication of at least one first of the lubrication clients, and a second lubrication system arranged to house a second lubricant, dedicated for lubrication of at least one second of the lubrication clients, the at least one second lubrication client comprising a seal arranged to seal the second lubrication system from a body of water surrounding at least a portion of the propeller drive assembly, the second lubrication system presents a bore in the propeller shaft for transport of the second lubricant, at least a portion of the bore extends in a non-zero angle to the propeller shaft.

2. A propeller drive assembly according to claim 1, wherein the second lubrication system arranged to house the second lubricant in the form of a biodegradable oil.

3. A propeller drive assembly according to claim 1, wherein the second lubrication system presents a feeding cavity for the second lubricant, the second lubrication system being arranged to transport the second lubricant from the feeding cavity to the seal.

4. A propeller drive assembly according to claim 3, wherein the propeller drive assembly comprises a propeller shaft supporting a propeller at a first end of the propeller shaft, and in that the feeding cavity is located at a second end of the propeller shaft, which second end is opposite to the first end.

5. A propeller drive assembly according to claim 1, wherein the seal is provided between the propeller shaft and a further part of the propeller drive assembly, wherein the bore is arranged for the transport of the second lubricant towards the seal.

6. A propeller drive assembly according to claim 1, wherein the second lubrication system is arranged to transport the second lubricant to the seal at least partly by the force of gravity.

7. A propeller drive assembly according to claim 1, wherein the second lubrication system is arranged to transport the second lubricant to the seal at least partly by force of gravity, and comprises a storage reservoir arranged to communicate with the bore, and adapted to be located above the bore.

8. A propeller drive assembly according to claim 1, wherein the propeller drive assembly comprises a propeller shaft for supporting a propeller, wherein the second lubrication system presents a bore in the propeller shaft for the transport of the second lubricant, and that the second lubrication system comprises an Archimedes screw for urging the second lubricant through the bore.

9. A propeller drive assembly according to claim 8, wherein the Archimedes screw is located in the bore.

10. A propeller drive assembly according to claim 1, wherein die propeller drive assembly comprises a propeller shaft, and that the propeller drive assembly comprises at least one seal which surrounds the propeller shaft and is arranged to separate the first and second lubricants.

11. A propeller drive assembly according to claim 1, wherein the propeller drive assembly comprises a first propeller shaft for supporting a first propeller, and a second propeller shaft for supporting a second propeller, tire second propeller shaft being tubular and coaxial with the first propeller shaft, the first propeller shaft being arranged at least partly inside the second propeller shaft, and that the second lubrication system presents a gap (5024) between the first and second propeller shafts for the transport of the second lubricant.

12. A propeller drive assembly according to claim 1, wherein the propeller drive assembly comprises a propeller shaft, and a driveshaft extending in a non-zero angle to the propeller shaft and engaging with the propeller shaft via a bevelled gear set.

13. A propeller drive assembly according to claim 1, wherein the propeller drive assembly comprises a first propeller shaft for supporting a first propeller, and a second propeller shaft for supporting a second propeller, the second propeller shaft being tubular and coaxial with the first propeller shaft, the first propeller shaft being arranged at least partly inside the second propeller shaft, that the propeller drive assembly further comprises a driveshaft extending in a non-zero angle to the first aid second propeller shafts, and being arranged to drive the first and second propeller shafts, and that the second lubrication system presents a bore in the first propeller shaft for the transport of the second lubricant from a first side of tire driveshaft in a direction towards a second side of the driveshaft, opposite to the first side, the seal being located on the second side of the driveshaft.

14. A propeller drive assembly according to claim 13, wherein the second lubrication system presents a gap between the first and second propeller shafts for transport of the second lubricant received from said the bore, on the second side of the driveshaft.

15. A propeller drive assembly according to claim 13, wherein a first seal is arranged to separate the first and second lubricants, and is provided on the first side of the driveshaft, between the first propeller shaft and a surrounding fixed part of the propeller drive assembly.

16. A propeller drive assembly according to claim 13, wherein a second seal is arranged to separate the first and second lubricants, and is provided on the second side of the driveshaft, between the first and second propeller shafts.

17. A propeller drive assembly according to claim 13, wherein a third seal is arranged to separate the first and second lubricants, and is provided on the second side of the driveshaft, between the second propeller shaft and a surrounding fixed part of the propeller drive assembly.

18. A propeller drive assembly according to claim 13, wherein the seal arranged to seal the second lubrication system from the body of water, is provided between the first and second propeller shafts.

19. A propeller drive assembly according to claim 13, wherein the seal arranged to seal the second lubrication system from the body of water, is provided between the second propeller shaft and a surrounding fixed part of the propeller drive assembly.

20. A water surface vessel, comprising an assembly according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples. In the drawings:

(2) FIG. 1 is perspective view from below of a water surface vessel provided with two propeller drive assemblies according to an embodiment of the invention.

(3) FIG. 2 is a cross sectional view of a portion of one of the propeller drive assemblies of the vessel in FIG. 1, the section being oriented along the rotational axis of the propellers thereof, and along a driveshaft of the assembly.

(4) FIG. 3 is a detail of the view in FIG. 2.

(5) FIG. 4 is a cross sectional view of a portion of a propeller drive assembly according to an alternative embodiment of the invention.

DETAILED DESCRIPTION

(6) FIG. 1 shows a water surface vessel in the form of a power boat with two engines 2, indicated with broken lines. Each engine 2 is adapted to drive a set of coaxially arranged counter-rotating propellers 3 which face forward in the forward travel direction of the vessel 1. The propeller sets are provided on a respective propeller drive assembly 5 in the form of a pod drive 5. The pod drives 5 are located side by side on a bottom side of the vessel, in the vicinity of a stem 101 thereof. The pod drives 5 are distributed in a horizontal, lateral direction of the vessel 1. It is understood that each propeller drive assembly 5 is arranged to transfer a torque between the respective engine 2 and the respective set of propellers 3.

(7) It should be noted that the invention is applicable to a variety of vessel types, and to a variety of propeller drive assemblies. For example, the propeller drive assemblies 5 may be provided in the form of sterndrives 5, located side by side on the stem 101. In further embodiments, a single, or more than two propeller drive assemblies may be provided.

(8) Reference is made to FIG. 2, showing a cross section of a portion of one of the propeller drive assemblies. The propeller drive assembly comprises a housing 513 supporting various pans as described below. The propeller drive assembly further comprises a two propeller shafts 511, 512 protruding from the housing. A first 511 of the propeller shafts is provided for supporting a first of the propellers 3 in the propeller set. The first propeller, which is not shown in FIG. 2, is mounted to a distal end of the first propeller shaft 511. In FIG. 2 the distal end is shown as an end protruding in the left part of the figure.

(9) A second 512 of the propeller shafts is provided for supporting a second of the propellers 3 in the propeller set. The second propeller shaft 512 is tubular and coaxial with the first propeller shaft 511, and the first propeller shaft 511 is arranged partly inside the second propeller shaft 512. The second propeller, which is not shown in FIG. 2, is mounted behind the first propeller in the forward travel direction of the vessel 1. More specifically, the second propeller is mounted between a flange 5122 at a distal end of the second propeller shaft 512, and the housing 513.

(10) The propeller drive assembly further comprises a driveshaft 514 extending substantially perpendicularly to the first and second propeller shafts 511, 512. The driveshaft 514 extends from the first and second propeller shafts 511, 512, which are located in a lower portion of the propeller drive assembly 5, upwards, and is arranged to deliver the torque from the respective engine 2.

(11) The driveshaft 514 is engaged with the propeller shafts 511, 512 via bevelled gear sets. More specifically, the driveshaft 514 comprises at its lower end a bevelled gear 5141. On a first side of the driveshaft 514, which first side in FIG. 2 is to the right of the driveshaft 514, i.e. opposite to the forward travel direction of the vessel 1, the bevelled gear 5141 of the driveshaft meshes with a bevelled gear 5111, herein also referred to as a first bevelled gear, fixed to the first propeller shaft 511. On a second side of the driveshaft 514, which second side in FIG. 2 is to the left of the driveshaft 514, i.e. in the forward travel direction of the vessel 1, the bevelled gear 5141 of the driveshaft meshes with a bevelled gear 5121, herein also referred to as a second bevelled gear, fixed to the second propeller shaft 512. This provides for the propellers on the first and second propeller shafts 511, 512 to be counter-rotating.

(12) The first propeller shaft 511 is supported by a first bearing 531 and a second bearing 532. The first bearing 531 is provided on the first side of the driveshaft 514, and supports the first propeller shaft against the housing 513. The second bearing 532 is provided on the second side of the driveshaft 514, and supports the first propeller shaft 511 against the second propeller shaft 512. A third bearing 533 and a fourth bearing 534 support the second propeller shaft 512 against the housing 513. A fifth bearing 535 supports the second propeller shaft 512 against the first propeller shaft 511. The fifth bearing 535 is located on the second side of the driveshaft. The third bearing 533 and the fourth bearing 534 are located between the second bearing 532 and the fifth bearing 535. A sixth bearing 536 supports the driveshaft 514 against the housing 513.

(13) The bearings 531-536 and number of seals, described below, form what is herein referred to as lubrication clients served by two lubrication systems. A first lubrication system 501 is arranged to house a first lubricant in a liquid form. The first lubricant is in this embodiment a traditional transmission oil. The first lubrication system 501 is dedicated for providing lubrication for what is herein referred to as first lubrication clients. The first lubrication clients include the first bearing 531, the third bearing 553, the fourth bearing 534, the fifth bearing 535 and the sixth bearing 536. The first lubrication system 501 is arranged to transport the first lubricant to the first lubrication clients 531, 533, 534, 535, 536.

(14) A second lubrication system 502 is arranged to house a second lubricant in a liquid form. The second lubricant is in this embodiment a biodegradable oil. The second lubrication system 502 is dedicated for providing lubrication for what is herein referred to as second lubrication clients which include the second bearing 532.

(15) The first and second lubricants are separated from each other and from the surrounding water by parts of the propeller drive assembly 5 including seals and the housing 513 with a plurality of walls 5131. A first seal 541, arranged to separate the first and second lubricants, is provided on the first side of the driveshaft 514, between the first propeller shaft 511 and the housing 513. A second seal 542, also arranged n separate the first and second lubricants, is provided on the second side of the driveshaft 514, between the first and second propeller shafts 511, 512. A third seal 543, also arranged to separate the first and second lubricants, is provided on the second side of the driveshaft 514, between the second propeller shaft 512 and the housing 513.

(16) A fourth seal 521 is arranged to separate the second lubricant from the water surrounding the propeller drive assembly, and is provided on the second side of the driveshaft 514, at the distal and of the second propeller shaft 512, and between the first and second propeller shafts 511, 512. A fifth seal 522 is also arranged to separate the second lubricant from the water, and is provided on the second side of the driveshaft 514, between the second propeller shaft 512 and the housing 513. The fourth seal 521 and the fifth seal 522 are arranged to be lubricated by the second lubrication system and are therefore herein referred to as second lubrication clients.

(17) The second lubrication system 502 presents, on the first side of the driveshaft 514, a feeding cavity 5021 for the second lubricant. Thus the feeding cavity 5021 is located at an end of the first propeller shaft 511, which end is opposite to the distal end 5111 at which the first propeller shaft 511 carries one of the propellers 3 (FIG. 1).

(18) The second lubrication system 502 further presents a bore 5022 in the first propeller shaft 511 for transport of the second lubricant from the feeding cavity 5021 in a direction towards the second side of the driveshaft 514. Tire bore 5022 presents a longitudinal portion which is coaxial with the first propeller shaft 511, and a lateral portion 5022b, or radial portion, on the second side of the driveshaft 514. The lateral portion 5022b leads from the longitudinal portion of the bore 5022 to a gap 5024 between the first and second propeller shafts 511, 512. The lateral portion 5022b allows the centrifugal force caused by the first propeller shaft rotation to act on the second lubricant in the lateral portion 5022b, to move the second lubricant along the lateral portion 5022b; to thereby assist in the transport of the second lubricant to the fourth and fifth seals 521, 522.

(19) Thus, the longitudinal bore portion is arranged to transport die second lubricant from the propeller shaft end at the feeding cavity 5021, to a position between the shaft ends, and the radial bore portion 5022b provides a communication between the longitudinal bore portion at said position and the exterior of the first propeller shaft 511. The gap 5024 is arranged guide the second lubricant from the bore 5022, on the second side of the driveshaft 514, towards the distal end of the second propeller shaft 512.

(20) Thus, the bore 5022 and the gap 5024 are arranged to guide the second lubricant from the feeding cavity 5021 to the second beating 532 and the fourth seal 521. Also, a lateral, i.e. radially extending hole 5025 in the second propeller shaft 512 is arranged to guide the second lubricant from the gap 502-1 to the fifth seal 522.

(21) Thus, the second lubrication system 502 is arranged to transport the second lubricant from the feeding cavity 5021 to the second lubrication clients including the second bearing 532 and the fourth and fifth seals 521,522.

(22) The second lubrication system 502 further comprises a storage reservoir 5026 arranged to communicate with the bore 5022 via the feeding cavity 5021. The storage cavity is located above the feeding cavity 5021 and the bore 5022. A feeding conduit 5027 extends between the storage reservoir 5026 and the feeding cavity 5021. This provides a gravity feed of the second lubricant from the storage reservoir 5026 to tire bore 5022. The second lubricant is fed further through the bore 5022 and onwards towards the fourth and fifth seals 521, 522 via the gap 5024, by the pressure created the force of gravity provided by the storage reservoir location. In addition, the storage reservoir is located so that it is easily accessible for a person servicing the propeller drive assembly, allowing such a person to refill second lubricant into the storage reservoir 5026 when needed. The storage reservoir 5026 presents a ventilation opening 5028 providing a communication with the atmosphere to allow air to enter to replace second lubricant which has been consumed by the second lubrication clients.

(23) It should be noted that in some embodiments, the feeding cavity 5021 may provide the entire storage function of the second lubrication system, and it may thereby be provided with a ventilation opening ensuring a communication with the atmosphere to allow air to enter to replace consumed second lubricant. In such embodiments the feeding cavity 5021 may thus also be what is herein referred to as a storage reservoir 5026. In other embodiments, the feeding conduit 5027 may extend to a fixed portion surrounding the propeller shaft 511, so that the conduit extends all the way to the bore 5022. In such embodiments, a lower pan of the feeding conduit 5027, in the vicinity of the bore 5022, may be regarded as what is herein referred to as a feeding cavity 5021.

(24) For further assisting in the transportation of the second lubricant, the second lubrication system comprises an Archimedes screw 5023 for urging the second lubricant through the bore 5022. The screw 5023 is located in a widened end of the bore 5022 at the feeding cavity 5021, and it is fixed to the first propeller shaft 511. In some embodiments, no such Archimedes screw is provided, and the transport of the second lubricant is effected

(25) FIG. 3 shows an enlarged view of a part of the fourth seal 521 in this embodiment in FIG. 2. The other seals therein, including the fifth seal 522, may be of the same type. The fourth seal 521 is a V ring seal which is fixed to the second propeller shaft 512. The fourth seal 521 is arranged to extend around the first propeller shaft 511, and to rotate in relation to the first propeller shaft 511. The fourth seal 521 presents a U-shaped cross-section, and a lip 5211 which abuts the first propeller shaft 511.

(26) The transport by the second lubrication system of the biodegradable oil to the fourth and fifth seals 521, 522 provides for a lubricating film at the seals to be renewed to avoid wear. Also, the biogradability of the second lubricant will minimise the environmental impact of any leakage of the lubricant into the water. The separation of the first and second lubricants provides for the first lubrication system, which may include considerably more lubrication clients than the second lubrication system, to provide an effective traditional transmission oil, e.g. a fully synthetic transmission oil. The second lubrication system may be seen as a barrier between the water and the environmentally less friendly traditional transmission oil.

(27) FIG. 4 shows a cross section of a propeller drive assembly 5 according to an alternative embodiment of the invention. The propeller drive assembly 5 is arranged to drive a single propeller, (not shown). The propeller drive assembly comprises a housing 513 and a propeller shaft 512 protruding from the housing. The propeller shaft 512 is arranged to support, on a distal end 5121 thereof, a propeller. The propeller drive assembly further comprises a driveshaft 514 extending substantially perpendicularly to the propeller shaft 512. The driveshaft 514 comprises at its lower end a bevelled gear 5141, which meshes with a bevelled gear 5121 fixed to the propeller shaft 512.

(28) The propeller shaft 511 is supported by bearings 531, 533, 534 against the housing 513. A further bearing 536 supports the driveshaft 514 against the housing 513.

(29) The bearings 531, 533, 534 and number of seals, described below, form lubrication clients served by two lubrication systems. A first lubrication system 501 is arranged to house a first lubricant in a liquid form. The first lubrication system 501 is dedicated for providing lubrication for first lubrication clients including the bearings 531, 533, 534. A second lubrication system 502 is arranged to house a second lubricant in a liquid form. The first and second lubricants are separated from each other and from the surrounding water by parts of the propeller drive assembly 5 including the housing 513 with a plurality of walls 5131, and seals 541, 543 provided between the propeller shaft 512 and the housing 513.

(30) The second lubrication system 502 is dedicated for providing lubrication for a second lubrication client in the form of a seal 522 arranged to separate the second lubricant from the water surrounding the propeller drive assembly 5. The seal 522 is provided between the propeller shaft 512 and the housing 513.

(31) The second lubrication system 502 presents a feeding cavity 5021 for the second lubricant. The feeding cavity 5021 is located at an end of the propeller shaft 512, which end is opposite to the distal end 5121 at which the propeller shaft 512 carries the propeller. The second lubrication system 502 further presents a bore 5022 in the propeller shaft 512 for transport of the second lubricant from the feeding cavity 5021 in a direction towards the distal end 5121 of the propeller shaft 512. The bore 5022 presents a longitudinal portion which is coaxial with the propeller shaft 512, and a lateral portion 5022b. The lateral portion 5022b leads from the longitudinal portion of the bore 5022 to the seal 522.

(32) Similarly to the embodiment described with reference to FIG. 2, for assisting in the transportation of the second lubricant from the feeding cavity 5021 towards the seal 522, the second lubrication system comprises a storage reservoir 5026 arranged to communicate with the bore 5022 via the feeding cavity 5021, and an Archimedes screw 5023 for urging the second lubricant through the bore 5022.

(33) Again, the transport by the second lubrication system of the biodegradable oil to the seal 522 provides for a lubricating film at the seal to be renewed to avoid wear. Also, the biogradability of the second lubricant will minimise the environmental impact of any leakage of the lubricant into the water. The second lubrication system may be seen as a barrier between the water and an environmentally less friendly traditional transmission oil of the first lubrication system.

(34) 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.