MARINE PROPULSION SYSTEM

Abstract

A marine propulsion system having an upper housing part, a pod, and a shank extending between the upper housing part and the pod. An underwater transmission having an input shaft and an output shaft is arranged in the pod and the input shaft is connected to a drive shaft that extends through the shank and is driven by an electric motor. The electric motor is mounted inside the shank and that surrounds the drive shaft.

Claims

1. A marine propulsion system comprising an upper housing part (10), a pod (12), and a shank (11) extending between the upper housing part (10) and the pod (12); an underwater transmission (120) having an input shaft (121) and an output shaft (122) arranged in the pod (12) and the input shaft (121) connected to a drive shaft (13) extending through the shank (11) and driven by an electric motor (14), the electric motor (14) being positioned inside the shank (11) and surrounding the drive shaft (13), and the drive shaft (13) connected to the electric motor (14) by a reduction gear (15) and the reduction gear (15) accommodated in the upper housing part.

2. The marine propulsion system according to claim 1, wherein the electric motor (14) extends beyond the shank into the upper housing part (10).

3. The marine propulsion system according claim 2, wherein the drive shaft (13) forms or is connected to the rotor of the electric motor (14).

4. The marine propulsion system according to claim 3, wherein the reduction gear (15) is a planetary gear.

5. The marine propulsion system according to claim 4, wherein the marine propulsion system is embodied as a rudder propeller with an adjusting drive for rotating the pod (12) around a vertical axis (V).

6. The marine propulsion system according to claim 5, wherein the marine propulsion system is embodied as a propulsion system that can be extended out from a hull.

7. The marine propulsion system according to claim 6, wherein the drive shaft (13) can be connected by a switchable clutch to an above-water transmission and can be driven.

8. The marine propulsion system according to claim 7, wherein the output shaft (122) is connected to a reduction gear (15a) embodied as a planetary gear.

9. The marine propulsion system according to claim 1, wherein the drive shaft (13) forms or is connected to the rotor of the electric motor (14).

10. The marine propulsion system according to claim 1, wherein the reduction gear (15) is a planetary gear.

11. The marine propulsion system according to claim 1, wherein the marine propulsion system is embodied as a rudder propeller with an adjusting drive for rotating the pod (12) around a vertical axis (V).

12. The marine propulsion system according to claim 1, wherein the marine propulsion system is embodied as a propulsion system that can be extended out from a hull.

13. The marine propulsion system according to claim 1, wherein the drive shaft (13) can be connected by a switchable clutch to an above-water transmission and can be driven.

14. The marine propulsion system according to claim 1, wherein the output shaft (122) is connected to a reduction gear (15a) embodied as a planetary gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other embodiments and details of this invention are explained in greater detail in view of embodiments shown in the drawings, wherein:

[0015] FIG. 1 is a schematic side view of a first embodiment of a marine propulsion system according to this invention;

[0016] FIG. 2 shows a schematic side view of a second embodiment of this invention;

[0017] FIG. 3 shows a schematic side view of a cooling of a first embodiment of this invention;

[0018] FIG. 4 shows a schematic side view of a cooling of a second embodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION

[0019] FIG. 1 shows a marine propulsion system according to a first embodiment, which is a rudder propeller that can be rotated around a vertical axis V by adjusting drives that are not shown, but are intrinsically known to those skilled in the art.

[0020] The marine propulsion system comprises an upper housing part 10, a pod 12, and a shank 11 extending between the upper housing part 10 and the pod 12. Whereas the upper housing part 10 is installed in stationary fashion in a hull that is not shown here, the shank 11 and the pod 12 can be pivoted around the axis V by the adjusting drive in order, in addition to propulsion, to also produce a control impulse for the watercraft that is equipped with it.

[0021] The pod 12 accommodates an underwater transmission 120, which has an input shaft 121 and an output shaft 122 that are arranged at a 90 angle with respect to each other. For example, the horizontally extending output shaft 122 supports a propeller labeled with the reference numeral 16 at one of its ends that extends out from the pod 12.

[0022] The input shaft 121 of the underwater transmission 120 is connected to a drive shaft 13, which is driven by an electric motor 14. The electric motor 14 draws its energy, for example, from suitable energy storage devices onboard the vessel or from an internal combustion engine in order to implement a diesel-electric drive.

[0023] In order to achieve a particularly compact propulsion system, the electric motor 14 is positioned inside the shank 11 and surrounds the drive shaft, with the electric motor 14 extending into the upper housing part 10.

[0024] The selected positioning of the electric motor 14 inside the shank 11, possibly extending into the upper housing part 10, achieves a particularly compact propulsion system, which can be easily integrated into a watercraft and requires only an extremely small amount of space. For this purpose, usually only the upper housing part 10 is accommodated inside the hull, whereas the shank 11 and the pod 12 protrude from the underside of the hull and are positioned underwater.

[0025] The upper housing part 10 thus accommodates only a part of the electric motor 14 and the adjusting drive, whereas the remaining part of the electric motor 14 is accommodated inside the shank.

[0026] Because the electric motor 14 is positioned inside the shank 11 and extends partially into the upper housing part 10, it is possible for a very long embodiment of the electric motor 14 to be integrated into the propulsion system, permitting a significant reduction in the outer diameter of the latter. The shank 11 thus achieves a cross-section that is advantageous from a flow standpoint despite the fact that it accommodates the electric motor 14.

[0027] The drive shaft 13 extends all the way through the electric motor 14 and is coupled to the input shaft 121 of the underwater transmission 122. The electric motor 14 acts on the drive shaft 13 via a reduction gear in the form of a planetary gear accommodated in the upper housing part 10. This planetary gear is driven by the electric motor 14 via a hollow shaft through which the drive shaft 13 extends. By providing such a reduction gear, only a slight drive torque is required from the electric motor 14 so that the dimensions of the electric motor 14 can be further reduced and it can also be accommodated in a shank 14 that is of only small dimensions.

[0028] In the embodiment according to FIG. 2, it is also possible to provide additional reduction gears, for example, in the vicinity of or near the pod 12, as indicated by the reference numeral 15a. For example, the output shaft 122 can be connected to a reduction gear 15a embodied in the form of a planetary gear and can be driven via the latter. In this way, it is possible to implement total gear ratios of i>20. By selectively adapting the gear ratios of the planetary gears 15, 15a, a very small ring gear can be used in the underwater transmission 120, which requires very advantageous L/D ratios.

[0029] In all of the embodiments explained above, the required oil volume in the marine propulsion system is reduced because a large part of the available space is already taken up by the electric motor 14 in the shank 11 and in the upper housing part 10. Depending on the embodiment of the marine propulsion system, it is possible to reduce the oil volume to only the underwater transmission inside the pod 12.

[0030] Naturally, the above-explained marine propulsion systems cannot only be installed in a stationary fashion in a hull, but can also be used in the form of marine propulsion systems that can be extended along the vertical axis V. Here, too, the positioning of the electric motor 14 inside the shank in the way proposed according to this invention offers significant advantages.

[0031] FIGS. 3 and 4 show two embodiments according to FIG. 1 of how the underwater transmission accommodated inside the pod 12 and the electric motor 14 can be cooled.

[0032] According to the exemplary embodiment shown in FIG. 3, the cooling of the propulsion system components is carried out exclusively by the water W flowing past underneath the hull S, whereas in the exemplary embodiment according to FIG. 4, an additional coolant circuit K is provided inside the marine propulsion system in addition to the cooling provided by the water W flowing past.