UNDERWATER PROPULSION UNIT

Abstract

An underwater propulsion unit is provided for an outboard motor or a pod drive. The underwater propulsion unit includes a plastic housing designed for water to flow around, and a metal housing in which an electrical drive is received. The electrical drive is received in the metal housing so as to be sealed off from the surroundings in a watertight manner, and the metal housing is arranged inside the plastic housing.

Claims

1. An underwater propulsion unit comprising: a plastic housing configured for water to flow around; and a metal housing configured to receive an electrical drive so as to be sealed off from surroundings in a watertight manner, wherein the metal housing is arranged inside the plastic housing that includes a plurality of openings that are connected via a flow channel, and wherein the plastic housing is configured such that, when the water flows around the plastic housing, the water flows at least partially around the metal housing.

2. The underwater propulsion unit according to claim 1, wherein the plastic housing comprises an inlet opening in a front region, and an outlet opening in a rear region, and the flow channel extends along a longitudinal axis of the underwater propulsion unit.

3. The underwater propulsion unit according to claim 1, wherein the flow channel is at least partially formed by the metal housing.

4. The underwater propulsion unit according to claim 1, wherein the plastic housing is connected to a shaft tube via a shaft tube molding.

5. The underwater propulsion unit according to claim 1, wherein the electrical drive comprises at least one of an electric motor, an optional transmission, and an electronic component.

6. The underwater propulsion unit according to claim 5, wherein the electrical drive is configured to drive a propeller via a drive shaft.

7. The underwater propulsion unit according to claim 1, wherein the metal housing comprises a metal tube that includes at least one of a front tube seal at a front end and a rear tube seal at a rear end thereof.

8. The underwater propulsion unit according to claim 7, wherein the metal housing comprises a cable seal at the front end thereof, for sealing a cable, and a shaft seal at the rear end thereof.

9. The underwater propulsion unit according to claim 1, wherein the plastic housing comprises a plurality of flow channels.

10. The underwater propulsion unit according to claim 9, wherein the flow channels are separated from one another by longitudinal ribs that fix the metal housing to and the plastic housing.

11. The underwater propulsion unit according to claim 9, wherein the flow channels each open out into at least one of separate inlet openings and outlet openings in the plastic housing.

12. The underwater propulsion unit according to claim 8, wherein the flow channels open out into at least one of a common inlet distributor and outlet distributor having a common inlet opening or outlet opening, respectively.

13. The underwater propulsion unit according to claim 1, wherein the metal housing is arranged substantially centrally in the plastic housing, and the plastic housing includes a cable guide channel between the metal housing and the plastic housing.

14. The underwater propulsion unit according to claim 2, wherein at least one of the openings and the flow channel comprise fixed or variable flow limitation means to adjust a flow through the flow channel.

15. The underwater propulsion unit according to claim 2, wherein at least one of the openings and the flow channel comprises turbulators that are connected to the metal housing.

16. The underwater propulsion unit according to claim 1, wherein the shaft tube is directly connected to the metal housing.

17. The underwater propulsion unit according to claim 6, wherein the shaft tube is directly connected to the metal housing by at least one of being welded, begin screwed or being riveted to the metal housing, and the shaft tube is formed in one piece with the metal housing.

18. A system comprising: at least two underwater propulsion units according to claim 1, wherein the at least two underwater propulsion units comprise at least one of an electrical drive of identical construction and a metal housing of identical construction, wherein each electrical drive is pre-set to a different power class, and wherein at least one dimension of the plastic housing is selected depending on the pre-set power class.

19. The system according to claim 18, wherein the first underwater propulsion unit is pre-set to a higher power class than the second underwater propulsion unit, and the plastic housing of the first underwater propulsion unit has at least one of a larger cross-section and a greater length than the plastic housing of the second underwater propulsion unit.

20. A boat comprising an underwater propulsion unit according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0057] Preferred embodiments of the invention are explained in greater detail by way of the following description of the figures, in which:

[0058] FIG. 1 is a simplified schematic cross-sectional view of an underwater propulsion unit according to a first embodiment, in a sectional plane extending in a longitudinal direction of the underwater propulsion unit;

[0059] FIG. 2 is a detailed cross-sectional view of an underwater propulsion unit according to a further embodiment, in a sectional plane extending in a longitudinal direction of the underwater propulsion unit;

[0060] FIG. 3 is a schematic cross-sectional view of the underwater propulsion unit according to FIG. 2, in a sectional plane oriented perpendicularly to the longitudinal axis of the underwater propulsion unit;

[0061] FIG. 4 is a schematic cross-sectional view of the underwater propulsion unit according to a further embodiment, in a sectional plane extending in a longitudinal direction of the underwater propulsion unit;

[0062] FIG. 5 is a perspective view of the underwater propulsion unit from FIG. 4; and

[0063] FIG. 6 is a schematic view of an underwater propulsion unit, in which the shaft tube is connected to the metal housing.

DETAILED DESCRIPTION

[0064] Preferred embodiments are described in the following, with reference to the figures. In this case, identical, similar, or identically acting elements are provided with identical reference signs in the different figures, and repeated description of these elements is omitted in part, in order to prevent redundancies.

[0065] FIG. 1 is a simplified schematic cross-sectional view of an underwater propulsion unit 10 according to a first embodiment. The underwater propulsion unit 10 is shown in a sectional plane extending in a longitudinal direction L of the underwater propulsion unit. The underwater propulsion unit 10 comprises a plastic housing 1 designed for water to flow around, and a metal housing 2 which is arranged in the plastic housing 1 and in which an electrical drive 3 is received.

[0066] The metal housing 2 is designed so as to be watertight, and receives the electrical drive 3. The metal housing 2 is in turn arranged completely inside the plastic housing 1. Therefore, a “shell-in-shell” principle is used, specifically a “metal housing-in-plastic housing” principle. In this case, the outer shell, the plastic housing 1, fulfils the function of flow optimization, since in operation of the underwater propulsion unit 10 water flows around the plastic housing 1. In this case, the inner shell, the metal housing 2, fulfils the function of cooling the metal housing 2, and thus ultimately cooling the electrical drive 3. The metal housing 2 is untreated and was produced substantially without surface treatment.

[0067] The plastic housing 1 is connected to a shaft tube 6. The connection of the shaft tube 6 to the plastic housing 1 is achieved via a shaft tube molding 7. In this case, the shaft tube 6 does not have to be sealed. The underwater propulsion unit 10 can be connected to a boat (not shown) via the shaft tube 6. The propulsion of the underwater propulsion unit 10 is generated in that an electrical drive 3 in the metal housing 2 drives a drive shaft 8, on which a propeller 9 is mounted.

[0068] FIG. 2 is a detailed cross-sectional view of an underwater propulsion unit 10 according to a further embodiment, in a sectional plane extending in a longitudinal direction of the underwater propulsion unit 10. The plastic housing 1 comprises openings 4 which are connected via a flow channel 5. In this case, the plastic housing 1 is designed such that, in the state in which water flows around the plastic housing 1, it flows around the metal housing 2, at least in part.

[0069] The openings 4 comprise an inlet opening 4′ formed in the front region of the plastic housing 1, and an outlet opening 4″ formed in the rear region of the plastic housing 1. The flow channel 5 extends between the inlet opening 4′ and the outlet opening 4″, substantially along a longitudinal axis L of the underwater propulsion unit 10.

[0070] The flow channel 5 of the underwater propulsion unit 10 is formed in part by the metal housing 2. This means that, in the state in which water flows around the plastic housing 1, it reaches the metal housing 2, via the inlet opening 4′ into the flow channel 5, and wets said housing. The heat transport between the metal housing 2 and the water flowing therearound is promoted by the water-metal housing effective surface pair. The metal housing 2 is watertight.

[0071] The plastic housing 1 is connected to a shaft tube 6. The connection of the shaft tube 6 to the plastic housing 1 is achieved via a shaft tube molding 7. In this case, the shaft tube 6 does not need to be sealed. The underwater propulsion unit 10 can be connected to a boat (not shown) via the shaft tube 6. The propulsion of the underwater propulsion unit 10 is generated in that an electrical drive 3 the metal housing 2 drives a drive shaft 8, on which a propeller 9 is mounted.

[0072] The underwater propulsion unit 10 shown in FIG. 2 comprises two flow channels 5. Accordingly, the underwater propulsion unit 10 comprises two inlet openings 4′ and two outlet openings 4″. The inlet openings 4 and the outlet openings 4″ are in each case formed as separate openings 4 in the plastic housing 1.

[0073] According to the drawing in FIG. 2, the metal housing 2 further comprises a metal tube 60 which comprises a front tube seal 61 at a front end, and a rear tube seal 62 at the rear end thereof. The metal tube 60 is a simple, untreated metal tube. The front tube seal 61 and the rear tube seal 62 can in each case be understood as covers. The metal tube 2 is sealed, via said covers, against entry of water. The covers can be connected to the metal tube 60 by screw connections, in particular via flanges, and optionally additionally by means of suitable seals. Furthermore, the metal housing 2 comprises a cable seal 63 at the front end thereof and a shaft seal 64 at the rear end thereof. In the specific embodiment, the cable seal 63 is arranged on the front tube seal 63, and the shaft seal 64 is arranged on the rear tube seal 62.

[0074] By means of the cable seal 63, which is arranged in the front tube seal 61 of the metal housing 3, a cable 65 is conducted out of the metal housing 2, into the cable guide channel 50, in a manner sealed off against entry of water. Subsequently, the cable 65 is conducted out of the cable guide channel 50, on the shaft tube molding 7, into the shaft tube 6.

[0075] In this case, the electrical drive 3 can comprise i) a motor, ii) a motor comprising a transmission, iii) a motor comprising electronics, and iv) a motor comprising a transmission and electronics.

[0076] FIG. 3 is a schematic cross-sectional view of the underwater propulsion unit 10 according to the embodiment shown in FIG. 2, in a sectional plane A-A which is oriented perpendicularly to the longitudinal axis L and extends through the front tube seal 61.

[0077] Therefore, FIG. 3 shows the underwater propulsion unit 10 which comprises a plastic housing 1 designed for water to flow around, and a metal housing 2 which is arranged in the plastic housing 1 and comprises an electrical drive (not shown). In this case, the plastic housing 1 comprises a plurality of flow channels 5 which are separated from one another via longitudinal ribs 20. The longitudinal ribs furthermore fix the metal housing 2 and the plastic housing 1 to one another. In this case, the metal housing 2 is arranged substantially centrally in the plastic housing 1. Furthermore, the plastic housing 1 comprises a cable guide channel 50 between the metal housing 2 and the plastic housing 1.

[0078] Via the cable seal 63, which is arranged in the front tube seal 61 of the metal housing 3, the cable 65 is conducted out of the metal housing 2, into the cable guide channel 50, in a manner sealed off against entry of water. Subsequently, the cable 65 is conducted out of the cable guide channel 50, on the shaft tube molding 7, into the shaft tube 6.

[0079] FIG. 4 is a schematic cross-sectional view of the underwater propulsion unit 10 according to a further embodiment, in a sectional plane extending in the longitudinal direction 11. Accordingly, the drawing in FIG. 4 shows an underwater propulsion unit 10 which comprises a plastic housing 1 designed for water to flow around, and a watertight metal housing 2 which is arranged in the plastic housing 1 and comprises an electrical drive 3. The plastic housing 1 comprises a plurality of flow channels 5 which in each case extend between separate inlet openings 4 and separate outlet openings 5. In this case, the plastic housing 1 is designed such that, in the state in which water flows around the plastic housing 1, it flows around the metal housing 2, at least in part. In the specific example, the flow around the metal housing 2 takes place via the flow through the individual flow channels 5. In this case, the respective flow channels 5 are formed in part by the metal housing 2. In the state in which water flows around the plastic housing 1, the water flowing therearound wets the outside of the metal housing 2.

[0080] The plastic housing 1 is connected to a shaft tube 6, the connection being achieved via a shaft tube molding 7. The electrical drive 3 of the underwater propulsion unit comprises an electric motor 31, a transmission 30, and an electronics component, and drives a propeller (not shown) via a drive shaft 8.

[0081] The metal housing 2 of the underwater propulsion unit 10 comprises a cable seal 63 (not shown) at the front end thereof, for sealing a cable 65, and a shaft seal 64 at the rear end thereof. In this case, the cable seal 63 is arranged on a front tube seal 61 which is arranged at a front end of the metal tube 60. The shaft seal 64 is arranged on a rear tube seal 62 which is arranged at a rear end of the metal tube 60.

[0082] The inlet openings 4′ have a substantially rectangular cross section having rounded edges. The outlet openings 4″ have a substantially oval cross section. In this way, hydrodynamically induced flow losses can be reduced, as a result of which efficient cooling of the metal housing 2 is made possible.

[0083] FIG. 5 is a perspective view of the underwater propulsion unit 10 from FIG. 4. As can be gathered from this drawing that the individual flow channels 5 of the underwater propulsion unit 10 comprise protrusions. In other words, the plastic housing 1 comprises protrusions. In this case, the respective inlet openings 4′ and outlet openings 4″ are formed at the start and end of each protrusion.

[0084] FIG. 6 shows an underwater propulsion unit 10 similar to the variant from FIG. 1, the difference here being that the shaft tube 6 is directly connected to the metal housing 2. In the embodiment shown, the connection is provided by a welding 22 of the shaft tube 6 to the metal housing 2.

[0085] The direct connection between the shaft tube 6 and the metal housing 2 can, however, also be achieved by screwing or riveting. In a further embodiment, the shaft tube 6 can be formed in one piece with the metal housing 2.

[0086] In the mentioned variants, the plastic housing 1 can likewise be connected to the shaft tube 6, as shown in FIG. 6. In this case, a shaft tube molding 7 is also provided, which serves for connecting the plastic housing 1 to the shaft tube 6.

[0087] However, in the case of a direct connection between the shaft tube 6 and the metal housing 2, the plastic housing 1 can also be arranged without contact with the shaft tube 6. The shaft tube 6 can be guided for example merely through one opening in the plastic housing 1.

[0088] If applicable, all the individual features set out in the embodiments can be combined and/or substituted with one another, without departing from the scope of the invention.

[0089] List of reference signs

TABLE-US-00001 1 plastic housing 2 metal housing 3 electrical drive 4 openings 4′ inlet openings 4″ outlet openings 5 flow channel 6 shaft tube 7 shaft tube molding 8 drive shaft 9 propeller 10 underwater propulsion unit 20 longitudinal ribs 22 welding 30 transmission 31 electric motor 50 cable guide channel 60 metal tube 61 front tube seal 62 rear tube seal 63 cable seal 64 shaft seal 65 cable