Propulsion Unit for a Marine Vessel

Abstract

A propulsion unit (1) for a marine vessel, comprising a shell structure (2), a shaft (4) rotatably coupled to a propulsion motor (3) inside the shell structure (2), and a propeller (5) coupled to the shaft (4) outside the shell structure (2). A shaft seal arrangement (6) is provided to engage the shaft (4), such that at least a first seal chamber (6a) is delimited between adjacent seal lips (6′) and the shaft (4). A first lubrication arrangement is provided for circulating a first lubricant through the first seal chamber (6a). The first lubrication arrangement (7) further comprises a first lubricant heat exchanger (7e) arranged at least partly outside of the shell structure (2) for conducting the first lubricant therethrough and for transferring heat from the first lubricant to an outside environment of the shell structure (2). A propulsion unit for a marine vessel, including a shell structure, a shaft rotatably coupled to a propulsion motor inside the shell structure, and a propeller coupled to the shaft outside the shell structure. A shaft seal arrangement is provided to engage the shaft, such that at least a first seal chamber is delimited between adjacent seal lips and the shaft. A first lubrication arrangement is provided for circulating a first lubricant through the first seal chamber. The first lubrication arrangement further includes a first lubricant heat exchanger arranged at least partly outside of the shell structure for conducting the first lubricant therethrough and for transferring heat from the first lubricant to an outside environment of the shell structure.

Claims

1. A propulsion unit, such as an azimuthing propulsion unit, for a marine vessel, the propulsion unit comprising: a shell structure mountable below a hull of an associated marine vessel such that the shell structure is at least partially immersed in water, when in use; a shaft extending between an inside and an outside of the shell structure through an opening provided thereat; a propeller, coupled to the shaft outside the shell structure so as to be rotatable by the shaft; a shaft seal arrangement comprising a plurality of seal lips axially spaced apart from each other and engaging the outer circumference of the shaft, such that at least a first seal chamber is delimited between adjacent seal lips and the outer circumference of the shaft, and a first lubrication arrangement, in turn, comprising: a first lubricant circulator; a first lubricant feed line for conducting a first lubricant to the first seal chamber via the first lubricant circulator, and a first lubricant return line for conducting said first lubricant from the first seal chamber back to the first lubricant circulator, wherein the first lubrication arrangement further includes first lubricant heat exchanger arranged at least partly in contact with an outside environment of the shell structure for conducting the first lubricant through the first heat exchanger and for transferring heat from the first lubricant to the outside environment of the shell structure.

2. The propulsion unit according to claim 1, wherein the shaft seal arrangement comprises a plurality of seal lips, such that additionally at least a second seal chamber is delimited between adjacent seal lips and the outer circumference of the shaft, and a second lubrication arrangement, in turn, comprising: a second lubricant circulator; a second lubricant feed line for conducting a second lubricant to the second seal chamber via the second lubricant circulator; a second lubricant return line for conducting said second lubricant from the second seal chamber back to the second lubricant circulator, and a second lubricant heat exchanger arranged at least partly outside of the shell structure for conducting second lubricant therethrough and for transferring heat from the second lubricant to an outside environment of the shell structure.

3. The propulsion unit according to claim 2, wherein the shaft seal arrangement comprises a plurality of seal lips, such that additionally at least a third seal chamber is delimited between adjacent seal lips and the outer circumference of the shaft, and, wherein the propulsion unit further comprises a regulator in fluid communication with the third seal chamber, such that a fluid pressure prevailing within the third seal chamber may be regulated with said regulator.

4. The propulsion unit according to claim 3, wherein the shaft seal arrangement comprises a plurality of seal lips, such that additionally at least a fourth seal chamber is delimited between adjacent seal lips and the outer circumference of the shaft, and, wherein the fourth seal chamber is an axially outermost seal chamber, such that an axially outermost seal lip associated with the fourth seal chamber is in direct contact with surrounding water, when in use. cm 5. The propulsion unit according to claim 1, wherein a portion of the first heat exchanger outside the shell structure is provided on an outside end surface of the shell structure facing the propeller, said portion of the first heat exchange preferably being at least partially covered by a cowling, such as a rope guard.

6. The propulsion unit according to claim 2, wherein a portion of the second heat exchanger outside the shell structure is provided on an outside end surface of the shell structure facing the propeller, said portion of the second heat exchanger preferably being at least partially covered by a cowling, such as a rope guard.

7. The propulsion unit according to claim 1, wherein the first lubrication arrangement comprises a first sensor configured to produce a first sensor signal indicative of first lubricant properties, the first sensor being coupled to a control unit configured to adjust output flow of the first lubricant circulator based on the first sensor signal.

8. The propulsion unit according to claim 11, wherein the control unit is configured to adjust output flow of the first lubricant circulator by controlling an associated circulator motor configured to drive said first lubricant circulator.

9. The propulsion unit according to claim 11, wherein the first sensor is provided as a first temperature sensor configured to produce a first sensor signal indicative of first lubricant temperature, and wherein the control unit is configured to increase output flow of the first lubricant circulator if the first sensor signal indicates an excessive first lubricant temperature, and/or decrease output flow of the first lubricant circulator if the first sensor signal indicates insufficient first lubricant temperature, or the first sensor is provided as a first pressure sensor indicative of a first lubricant pressure prevailing in the first seal chamber, and wherein the control unit is configured to increase output flow of the first lubricant circulator if the first sensor signal indicates an insufficient first lubricant pressure, and/or decrease output flow of the first lubricant circulator if the first sensor signal indicates excessive first lubricant temperature.

10. The propulsion unit according to claim 2, wherein the second lubrication arrangement comprises a second sensor configured to produce a second sensor signal indicative of second lubricant properties, the second sensor being coupled to a control unit configured to adjust output flow of the second lubricant circulator based on the first sensor signal.

11. The propulsion unit according to claim 13, wherein the control unit is configured to adjust output flow of the second lubricant circulator by controlling an associated circulator motor configured to drive said second lubricant circulator.

12. The propulsion unit according to claim 13, wherein either or both of the second sensor is provided as a second temperature sensor configured to produce a second sensor signal indicative of second lubricant temperature, and wherein the control unit is configured to increase output flow of the second lubricant circulator if the second sensor signal indicates an excessive second lubricant temperature, and/or decrease output flow of the second lubricant circulator if the second sensor signal indicates insufficient second lubricant temperature, or the second sensor is provided as a second pressure sensor indicative of a second lubricant pressure prevailing in the second seal chamber, and wherein the control unit is configured to increase output flow of the second lubricant circulator if the second sensor signal indicates an insufficient second lubricant pressure, and/or decrease output flow of the second lubricant circulator if the second sensor signal indicates excessive second lubricant temperature.

13. The propulsion unit according to claim 2, wherein both the first lubricant circulator and the second lubricant circulator are driven by a shared circulator motor.

14. The propulsion unit according to claim 1, wherein further comprising a propulsion motor arranged within the shell structure, and wherein the propulsion motor is rotatably coupled with the shaft such that the propeller is rotatable by the propulsion motor.

15. A marine vessel, wherein comprising a propulsion unit, such as an azimuthing propulision unit, for a marine vessel, the propulsion unit having: a shell structure mountable below a hull of an associated marine vessel such that the shell structure is at least partially immersed in water, when in use: a shaft extending between an inside and an outside of the shell structure through an opening provided thereat: a propeller coupled to the shaft outside the shell structure so as to be rotable by the shaft: a shaft seal arrangement comprising a plurality of seal lips axially spaced apart from each other and engaging the outer circumference of the shaft, such that at least a first seal chamber is delimited between adjacent seal lips and the outer circumference of the shaft, and a first lubrication arrangement, in turn, having: a first lubricant circulator; a first lubricant feed line for conducting a first lubricant to the first seal chamber via the first lubricant circulator, and a first lubricant return line for conducting said first lubricant from the first seal chamber back to the first lubricant circulator, wherein the first lubrication arrangement further comprises a first lubricant heat exchanger arranged at least partly in contact with an outside environment of the shell structure for conducting the first lubricant through the first heat exchanger and for transferring heat from the first lubricant to the outside environment of the shell structure.

16. The propulsion unit according to claim 2, wherein a portion of the first heat exchanger outside the shell structure is provided on an outside end surface of the shell structure facing the propeller, said portion of the first heat exchange preferably being at least partially covered by a cowling, such as a rope guard.

17. The propulsion unit according to claim 2, wherein the first lubrication arrangement comprises a first sensor configured to produce a first sensor signal indicative of first lubricant properties, the first sensor being coupled to a control unit configured to adjust output flow of the first lubricant circulator based on the first sensor signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which

[0057] FIG. 1 is a schematic representation of a propulsion unit according to an embodiment of the present disclosure;

[0058] FIG. 2 is more detailed schematic representation of FIG. 1

[0059] FIG. 3 is a partially cut view of a propulsion unit according to an embodiment of the present disclosure as seen from a perspective view;

[0060] FIG. 4 is a perspective view of the propulsion unit shown in FIG. 3, and

[0061] FIG. 5 is a perspective view of the propulsion unit shown in FIG. 3 with heat exchangers being covered.

DETAILED DESCRIPTION

[0062] FIG. 1 is a schematically represent a propulsion unit according to an embodiment of the present disclosure. Particularly, the propulsion unit 1 is intended to be attached to a marine vessel beneath the hull thereof. The propulsion unit 1 has a shell structure, i.e., a casing, in which a propulsion motor 3 is housed. A propeller 5 is arranged outside the shell structure 2 and is coupled to the propulsion motor 3 with a propeller shaft 4. The propeller shaft 4 penetrates through the shell structure 2, while a shaft seal arrangement 6 seals the inside of the shell structure 2 from an outside thereof the interface of the propeller shaft 4 and the shell structure 2. A first lubrication arrangement 7 and a second lubrication arrangement 8 are provided for lubricating and cooling the shaft seal arrangement 6, while a control unit 10 is provided for controlling said lubrication arrangement 7, 8.

[0063] FIG. 2 is more detailed schematic representation of the first lubrication arrangement, the second lubrication arrangement, and other entities associated thereto, of the embodiment illustrated in FIG. 1. Particularly, the shaft seal arrangement 6 comprises a plurality of seal lips 6′ engaging with propeller shaft 4. A first seal chamber 6a is delimited between adjacent axially adjacent seal lips 6′ and the propeller shaft 4. In the embodiment of FIG. 2, the first seal chamber is also an axially innermost seal chamber. A second seal chamber 6b is also delimited between axially adjacent seal lips 6′ and the propeller shaft 4. In the illustrated embodiment, the second seal chamber 6b is axially adjacent to the first seal chamber 6a, i.e., they are separated by a mutual seal lip. A third seal chamber 6c is also delimited between axially adjacent seal lips 6′ and the propeller shaft 4. In the illustrated embodiment, the third seal chamber 6c is axially adjacent to the second seal chamber 6b, i.e., they are separated by a mutual seal lip 6′. A fourth seal chamber 6d is also delimited between axially adjacent seal lips 6′ and the propeller shaft 4. In the illustrated embodiment, the fourth seal chamber 6c is an axially outermost seal chamber and axially adjacent to the third seal chamber 6c, i.e., they are separated by a mutual seal lip 6′.

[0064] The first seal chamber 6a is associated to a first lubrication arrangement 7, such that a first lubricant lubricates and cools the first seal chamber and the seal lips 6′ associated thereto. Particularly, the first lubricant from a first lubricant reservoir 7a, provided as a separate tank, is circulated through the first seal chamber 6a by a first lubricant circulator 7b, after which the first lubricant is again returned to the first lubricant reservoir 7a. Before entering the first seal chamber 6a, the first lubricant is conducted through a first heat exchanger 7e, which is at least partly in contact with the environment surrounding the shell structure, such that thermal exchange between the first lubricant and the surrounding environment is achieved. A first bypass valve 7f is also provided in connection with the first heat exchanger, such that the first lubricant can be directed past the first heat exchanger 7e, e.g., in case of failure thereof, thereby preventing the risk of lubricant leakage to the surrounding environment. In the illustrated embodiment, the first bypass valve 7f also provides a closed position, in which first lubricant circulation is halted altogether. The first lubricant arrangement is also provided with a first sensor 7g. In the illustrated embodiment, the first sensor 7g is a temperature sensor arranged downstream of the first seal chamber 6a, although other types of sensors and placements thereof may be envisaged. The first sensor 7g is couple to a control unit 10, which adjusts the output flow of the first lubricant circulator 7b by controlling a circulator motor 7b′ driving the first lubricant circulator.

[0065] In a similar manner, the second seal chamber 6b is associated to a second lubrication arrangement 8, such that a second lubricant lubricates and cools the second seal chamber and the seal lips 6′ associated thereto. Particularly, the second lubricant from a second lubricant reservoir 8a, provided as a separate tank is circulated through the second seal chamber 6b by a second lubricant circulator 8b, after which the second lubricant is again returned to the second lubricant reservoir 8a. Before entering the second seal chamber 6b, the second lubricant is conducted through a second heat exchanger 8e, which is at least partly in contact with the environment surrounding the shell structure, such that thermal exchange between the second lubricant and the surrounding environment is achieved. A second bypass valve 8f is also provided in connection with the second heat exchanger, such that the second lubricant can be directed past the second heat exchanger 8e, e.g., in case of failure thereof, thereby preventing the risk of lubricant leakage to the surrounding environment. In the illustrated embodiment, the second bypass valve 8f also provides a closed position, in which second lubricant circulation is halted altogether. The second lubricant arrangement 8 is also provided with a second sensor 8g. In the illustrated embodiment, the second sensor 8g is a temperature sensor arranged downstream of the second seal chamber 6b, although other types of sensors and placements thereof may be envisaged. The second sensor 8g is couple to a control unit 10, which adjusts the output flow of the second lubricant circulator 8b by controlling a circulator motor 8b′ driving the second lubricant circulator.

[0066] In the illustrated embodiment, the first lubricant reservoir 7a is coupled to a first lubricant supply line 7a′ for filling said first lubricant reservoir 7a. Correspondingly, the second lubricant reservoir 8a is coupled to a second lubricant supply line 8a′ for filling said second lubricant reservoir 8a.

[0067] In the illustrated embodiment, both the first lubricant circulator 7a and the second lubricant circulator 8a are driven by the same circulator motor 7b′, 8b′, although separate motors may also be implemented

[0068] In the illustrated embodiment, an air supply line 11 is coupled to the second lubricant reservoir 8a, and also to the first lubricant reservoir 7a via a respective regulator so as to set a desired reservoir pressure within the first lubricant reservoir 7a, lower than that of the air supply line 11.

[0069] Furthermore, the air supply line 11 is also coupled to the third seal chamber 6c along a regulator line 9a, such that a pressure prevailing within the third seal chamber 6c may be regulated. That is, the pressure prevailing within the third seal chamber is set, so as to counteract a hydrostatic pressure prevailing in the environment surrounding the shell structure 2, i.e. to smoothen out the pressure differential acting over the seal arrangement 6 Although other arrangement are possible, the enclosed drawings illustrate an embodiment in which the pressure prevailing in the second lubricant reservoir 8a and the third seal chamber 6c are governed by the pressure prevailing in the air supply line 11, while a separate regulator for governing the pressure prevailing in the first lubricant reservoir 7a is provided.

[0070] The third seal chamber 6c is further coupled to a drainage reservoir 9c with a drainage line 9b. This enables any water the fourth seal chamber 6d or lubricant from the second seal chamber 6b leaking over to the third seal chamber 6c to be drained therefrom. Effectively, any lubricant from the second seal chamber 6b is prevented from contaminating environment surrounding the shell structure 2.

[0071] When in use, the first seal chamber 6a and second seal chamber 6b are chiefly occupied by the first lubricant and the second lubricant, respectively. The third seal chamber 6c is chiefly occupied by air fed via the regulator line 9a, and the fourth seal chamber 6d is chiefly occupied by water from the surrounding environment.

[0072] FIG. 3 is a partially cut view of a propulsion unit 1 according to an embodiment of the present disclosure as seen from a perspective view. Particularly FIG. 3 illustrates the shell structure 2 defining an inner space, housing components of the propulsion unit 1, as discussed above. Furthermore, a portion of the shaft 4, namely a sleeve thereof can be seen extending through the shell structure 2. The seal arrangement 6 is provided surrounding the propeller shaft 4. Morevoer, portions of the first heat exchanger 7e and the second heat exchanger 8e can be seen on an end face of the shell structure 2 surrounding the propeller shaft 4.

[0073] FIG. 4 is a perspective view of the propulsion unit shown in FIG. 3. FIG. 4 more clearly illustrates the arrangement, in which the first heat exchanger and second heat exchanger annularly surround the propeller shaft 4.

[0074] FIG. 5 is a perspective view of the propulsion unit shown in FIG. 3 and FIG. 4. with the exception of the heat exchanger being covered by a separate cowling in the form of a rope guard 12.

[0075] Although the annexed drawings discuss the present disclosure in connection with an embodiment employing a first lubrication arrangement 7 and second lubrication arrangement, it should be understood that the present disclosure encompasses propulsion units implemented with a single lubrication arrangement, or alternatively, with more than two lubrication arrangements.