Drive for a watercraft

Abstract

The invention relates to a propulsion system (1) for a watercraft, designed as a pump jet, comprising a housing (10) with at least one inlet channel (14) and at least one outlet nozzle (15) communicating therewith, and a propeller arranged between the at least one inlet channel (14) and the at least one outlet nozzle (15), designed as an impeller (13) and rotatable via a drive motor, by means of which water is drawn into the housing (10) via the inlet channel (14), accelerated, and expelled from the housing as a jet of thrust via the outlet nozzle (15), wherein the housing (10) is rotatable about a steering axis (S) by means of a steering drive, and the drive motor comprises an annular stator (11) fixed in the housing (10) and a rotor (12) received therein, which forms the impeller (13).wherein the housing (10) comprises a stationary inner part (100) and an outer part (101) rotatably mounted on the inner part (100) about the control axis (S) and the stator (11) is fixedly connected to the inner part (100).

Description

[0001] The invention relates to a propulsion system for a watercraft, designed as a pump jet, comprising a housing with at least one inlet channel and at least one outlet nozzle communicating with it, and a propeller arranged between the at least one inlet channel and the at least one outlet nozzle, designed as an impeller and rotatable via a drive motor, by means of which water is drawn into the housing via the inlet channel, accelerated and expelled from the housing as a jet of thrust via the outlet nozzle, wherein the housing is rotatable about a control axis by means of a steering drive and the drive motor comprises an annular stator fixed in the housing and a rotor received therein, which forms the impeller.

[0002] Pump-jet propulsion systems for watercraft are widely known and, due to their operating principle, are also referred to as water jet propulsion. They are primarily a propulsion unit with a reaction drive for a variety of applications, such as in specialized vessels and rescue units, but also in amphibious military vehicles and submersible underwater vehicles. A high-speed, lightweight gasoline or diesel engine or gas turbine drives an impeller—that is, a shrouded propeller—which draws water from under the hull and expels it through movable nozzles. Pump-jet propulsion enables efficient vector control by swiveling the nozzle in the direction the watercraft is to turn. Reverse travel is also possible in this way.Compared to classic propeller-driven watercraft, jet-driven watercraft can be built and operated extremely flat and are extremely maneuverable even at the slowest speeds.

[0003] From the generic WO 2009 / 071077, such a pump-jet waterjet propulsion system for a watercraft is known, the inlet and outlet channels of which are arranged in a housing rotatable about the steering axis, which also acts as a diffuser. To achieve a particularly compact design, the drive motor is formed by a magnetic motor integrated into the housing, comprising an annular stator and a similarly annular rotor rotating within it, which also forms the impeller. However, since the stator is located within the rotatable housing, its energy supply must be provided via slip rings in the area of ​​the housing's bearings. This is extremely costly and, due to the design of the sliding contacts, susceptible to wear, especially in the presence of vibrations, which are unavoidable during ship operation.

[0004] From DE 199 05 141 A1, however, a pump-jet waterjet drive is known, the impeller of which is driven by a drive shaft extending from the housing into the ship's hull and a bevel gear by a drive motor located in the ship's hull. The housing has a part fixedly connected to the ship's hull in the area where the drive shaft passes through, and a part rotatable about the control axis, sealed against this, which also includes the outlet nozzle of the jet. Such a drive is very complex in design and requires a large amount of installation space due to the shaft drive and the drive motor located in the ship's hull, which is extremely disadvantageous.

[0005] The object of the invention is to propose a drive of the type mentioned above which overcomes the disadvantages of the prior art.

[0006] To solve the problem posed, it is proposed according to the invention that the pump jet has an annular stator fixed in the housing and a rotor received therein, which comprises the impeller, wherein the housing is divided into a stationary, fixed inner part and an outer part rotatably mounted on the inner part about the control axis and the stator is fixed to the inner part, thus also being fixedly connected to the stationary inner part.

[0007] According to the invention, the housing is thus designed in two parts and comprises a stationary inner part and an outer part that is rotatable about the control axis to maintain the control function. The stator of the magnetic motor provided according to the invention is fixed to the inner part and, like the inner part, is arranged in a stationary position. However, the rotor is arranged to rotate freely within the stator, and the outer part can be rotated about the control axis relative to the stationary inner part by means of the control drive to ensure the control function of the pump jet drive according to the invention. Since, according to the invention, the inner part and the stator are rigidly connected to each other, the need to ensure the energy supply of the stator via complex and failure-prone slip rings is eliminated.

[0008] In one possible embodiment of the invention, the outer part of the housing, which is rotatable about the control axis, comprises the at least one inlet channel and the at least one outlet nozzle, which are preferably arranged radially to the outer part and are arranged opposite each other with respect to the control axis.

[0009] Alternatively, it is also possible to arrange the inlet channel and / or the outlet channel in the area of ​​the underside of the pump jet in a manner known per se. The outlet channel is preferably always integrated into the outer part in order to achieve the desired rotation about the control axis for controlling the thrust jet.

[0010] According to a further aspect of the invention, the impeller is rotatably mounted on a fixed axle attached to the inner part, thus ensuring a particularly simple mechanical design. The mounting can be encapsulated and requires only a dynamic seal against seawater. Alternatively, the impeller can also have an axle or axle stub projecting towards the inner part, which is rotatably mounted in the fixed inner part.

[0011] Depending on the application, the drive according to the invention can be permanently installed on or in a ship's hull or designed as a retractable drive which, in a state installed in the hull of a watercraft, can be moved between a retracted rest position and an extended working position, wherein the drive in the extended working position can be extended to such an extent that the at least one inlet channel and the at least one outlet nozzle protrude beyond the hull of the watercraft.

[0012] The connection of the drive according to the invention to the hull of a watercraft can be achieved, for example, by connecting the inner part to a flange for fixing it in the watercraft, wherein the flange can be firmly connected to the hull of the watercraft due to the fixed arrangement of the inner part, for example by bolting it. It is also possible to fix the flange to the watercraft via elastically compliant shock bearings in order to minimize operating noise and / or to make the drive resistant to external shock loads.

[0013] According to a further proposal of the invention, the inner part comprises a deflecting arch for reversing the flow direction of the water drawn in by the impeller via the inlet channel and accelerated towards the at least one outlet nozzle.

[0014] According to one embodiment of the invention, the inner part comprises a pot-shaped receiving chamber that is separated from the water-carrying areas of the inner part and from the areas that come into contact with the water conveyed by the drive. The stator is fixedly inserted into this receiving chamber, with the rotor arranged to rotate within the stator; that is, the receiving chamber serves to hold both the stator and the rotor. The rotor is connected to the impeller running in the outer part via a corresponding shaft that extends from the receiving chamber in a sealed bearing.

[0015] According to an alternative proposal of the invention, the stator is fixedly connected to the inner part via retaining struts, and the electrical connecting lines of the stator, as well as optionally control lines, sensor lines, etc., run along or within the retaining struts from the inner part to the stator, which is why the retaining struts are preferably designed as a hollow profile.

[0016] In addition to the stationary fixing of the stator to the inner part and the guiding of the connecting lines leading to the stator, the retaining struts can, according to a further proposal of the invention, be shaped or provided with a flow profile in such a way as to counteract a swirl induced in the accelerated water by the impeller. Normally, the rotating impeller, which propels the water jet, imparts a corresponding swirl to the accelerated water due to its rotational movement, leading to efficiency losses. By appropriately shaping the surface of the retaining struts, which are exposed to the accelerated water as it passes through the housing, this swirl can be counteracted; that is, the accelerated water jet is de-swirled by the retaining struts, thereby significantly increasing efficiency.

[0017] For this purpose, the support struts can be arranged at equal or different intervals from each other, depending on the requirements, and can have the same or different cross-sections. For example, some support struts can be larger to accommodate the connecting lines to the stator, as well as any control and measuring lines, while other support struts have a special contour on their flow-enclosed surfaces to reduce the swirl of the accelerated water jet.

[0018] Further embodiments and details of the drive according to the invention are explained below with reference to the drawing illustrating an exemplary embodiment. The drawing shows: Figure 1 shows an embodiment of the invention in a perspective sectional view; Figure 2 shows a further embodiment of the invention.

[0019] The Figure 1Figure 1 shows a perspective view of a section through a pump jet drive 1 of a watercraft, which generates a thrust jet exiting a nozzle 15, which generates propulsion and a steering torque for the watercraft equipped with it.

[0020] The drive 1 comprises a housing 10 with several inlet channels 14 for water drawn in from outside the hull, which then enters a vestibule 140 located inside the housing 10.

[0021] Above the antechamber 140, a vertically oriented propeller in the form of an impeller 13 is arranged, which is set in rotation by a drive motor which will be explained in more detail below and by means of its propeller blades not only causes the water to be drawn into the antechamber 140 via the inlet channels 14, but also accelerates the water from the antechamber 140 vertically upwards in the direction of a deflecting arch 16, along which the accelerated water jet is reversed in the flow direction indicated by arrows and flows downwards in the direction of the outlet nozzle 15 which is arranged diametrically opposite to the inlet channels 14, through which the water jet is then expelled from the drive 1.

[0022] The housing 10 of the drive 1 is divided into an inner part 100 and an outer part 101, wherein the inner part 100 is fixed in a fixed position in the hull of the watercraft (not shown here) via a flange 18 in a manner not shown in detail, for example by screwing it in place and is thus fixed in position.

[0023] In contrast, the outer part 101 is sealed to the inner part 100 by means of double-acting seals 105, 103, but is freely rotatable about the vertically extending control axis S by means of a drive motor 17 in order to rotate the outlet nozzle 15 endlessly into any desired orientation about the control axis S in a manner known per se and to generate control impulses for the watercraft thus equipped by means of the drive 17. A circumferential annular gap 104 is provided between the inner part 100 and the outer part 101, which ensures the free rotation of the outer part 101 relative to the stationary inner part 100, the annular space 106 formed between the inner part 100 and the outer part 101 behind the annular gap 104 being sealed by the gap seal 103. Radially outward-leading relief bores can also be arranged in this area to provide pressure relief.

[0024] The upper end of the drive 1 is formed by an annular cover 180 resting on the flange 18.

[0025] A key feature of the illustrated drive 1 is that the drive motor of the impeller 13 is formed by a magnetic or induction motor arranged entirely within the housing 10, which has a stationary annular stator 11 and a similarly annular rotor 12 rotating within the stationary stator 11, which also encompasses the impeller 13.

[0026] The stationary and thus fixed annular stator 11 is attached to the deflection arch 16 of the also stationary inner part 100 of the housing 10 via a plurality of retaining struts 102, wherein the electrical connecting lines for the winding system of the stator 11 and the sensor system of the stator 11 are led through the retaining struts 102, which are designed as hollow profiles, to the inner part 11 and from there out of the flow space, so that the drive 1 does without slip rings or similar components, since the lines are guided exclusively through stationary components of the drive.

[0027] The rotor 12, which carries the propeller blades of the impeller 13, is rotatably mounted on a centrally formed hub on a rigid axle 108 projecting downwards from the inner part 100. This results in a particularly robust and wear-resistant arrangement of the impeller 13 within the housing 10. The bearing of the hub on the axle 108 can be encapsulated and requires only a dynamic seal above against seawater.

[0028] Since a rotating impeller 13 inevitably imparts a corresponding swirl to the water jet it propagates and accelerates, leading to efficiency losses, the support struts 102, around which the accelerated water jet flows, can have such a profile or cross-sectional design and orientation that they not only allow the passage of the connecting and control lines for the stator 11, but also give the water jet a flow direction opposite to the swirl, thus resulting in an overall reduction of the swirl in the water jet propagated and accelerated by the impeller 13. This allows the pressure of the thrust jet generated in the drive 1 to be maximized, while simultaneously minimizing the required control torque of the control drive 17 for rotating the outer part 101 about the control axis S during the operation of the impeller 13.

[0029] Furthermore, the housing 10 can be designed as a diffuser to increase the pressure. The diffuser can be configured as in Figure 1 It may be depicted or designed as a ring diffuser.

[0030] In addition to its particularly compact and wear-resistant design, the drive described above offers a further advantage in that it requires very little oil, so that the required size of a pressure transmitter, for example, can be reduced to less than 10 liters of oil volume.

[0031] In addition to a rigid connection of the flange 18 to the hull of the watercraft (not shown here), this can also be carried out with the intermediate placement of shock bearings in order to increase the resistance of the drive 1 to external shock waves.

[0032] Due to the integration of the drive motor within the housing 1, the space gained above the housing 1 can be used, compared to conventional pump jets, to arrange a movement mechanism there, which consists, for example, of synchronous cylinders that are controlled by a pump located in the interior, which may be filled with oil at neutral pressure, in order to move the drive as required from a retracted rest position to an extended working position, whereby the drive can be extended in the extended working position to such an extent that the at least one inlet channel 14 and the at least one outlet nozzle 15 project beyond the hull of the watercraft, while in the retracted rest position, piston rods exposed to seawater are retracted and protected from fouling and no change in volume occurs.

[0033] An alternative design of the drive 1 nsch Figure 1 is in the Figure 2shown, where identical parts have the same reference symbols as in the Figure 1 These features are not explained again separately to avoid repetition, unless this is necessary for understanding the invention. Regarding the explanations concerning Figure 1 Reference can be made to this.

[0034] Even in the exemplary embodiment of the Figure 2 The drive 1 is designed with a housing 10 divided into an inner part 100 and an outer part 101, wherein the outer part 101 has both the inlet channels 14 and the outlet nozzle 15 diametrically opposite each other and can be rotated about the control axis S relative to the stationary inner part 100 by means of a control drive 17.

[0035] The impeller 13 rotates about a vertical axis of rotation within the outer part 101 and conveys water from the antechamber 140 along the deflection arch 16 defined by the inner part 100 to the outlet nozzle 15. For this purpose, the impeller is mounted on a vertically extending axis 108, which extends vertically upwards and is rotatably mounted in a sealed bearing 109 of the inner part 100.

[0036] The axis 108 extends into a pot-shaped receiving chamber 107, centrally located on the inner part 100 and closed at the top by a cover 110. The stator 11 is inserted into the receiving chamber 107, which is thus sealed off from the water-bearing areas or areas that do not come into contact with the conveyed water in the drive 1, and is therefore firmly connected to the stationary inner part 100. Neither the inner part 100 nor the stator 11 rotates around the control axis S. The rotor 12, mounted on the axis 108, is arranged to rotate radially inside the stator 11, thus forming a magnetic motor consisting of the stator 11 and rotor 12 to drive the impeller 13.

[0037] The electrical power supply to the stator can pass directly through the wall of the receiving chamber 107, so that sliding contacts are also not necessary.

[0038] In contrast to the embodiment shown in Figure 1 in the exemplary embodiment according to Figure 2 the components of the magnetic motor, namely stator 11 and rotor 12, are not in contact with the pumped water of the drive 1.

[0039] The drive described above is suitable for integration into a wide variety of watercraft and, due to its small size, can also be retrofitted to suitable watercraft. Reference symbol list:

[0040] 1: Drive 10: Housing 11: Stator 12: Rotor 13: Impeller 14: Inlet duct 15: Outlet nozzle 16: Deflection arch 17: Steering drive 18: Flange 100: Inner part 101: Outer part 102: Retaining struts 103: Gap seal 104: Annular gap 105: Seal 106: Annular space 107: Receiving space 108: Shaft 109: Bearing 110: Cover 140: Pre-chamber 180: Lid S: Steering axle

Claims

1. Propulsion (1) of a watercraft, designed as a pump jet and comprising a housing (10) with at least one inlet channel (14) and at least one outlet nozzle (15) communicating therewith, and a propeller arranged between the at least one inlet channel (14) and the at least one outlet nozzle (15), designed as an impeller (13) and rotatable via a drive motor, by means of which water is drawn into the housing (10) via the inlet channel (14), accelerated and expelled from the housing as a jet of thrust via the outlet nozzle (15), wherein the housing (10) is rotatable about a steering axis (S) by means of a steering drive, and the drive motor comprises an annular stator (11) fixed in the housing (10) and a rotor (12) received therein, which includes the impeller (13), characterized by the fact thatthe housing (10) comprises a stationary inner part (100) and an outer part (101) rotatably mounted on the inner part (100) about the control axis (S) and the stator (11) is fixedly connected to the inner part (100).

2. Drive (1) according to claim 1, characterized by the fact that the outer part (101) comprising at least one inlet channel (14) and at least one outlet nozzle (15).

3. Drive (1) according to one of claims 1 or 2, characterized by the fact that the impeller (13) is rotatably mounted on a fixed axle (108) attached to the inner part (100) or the impeller (13) has an axle projecting towards the inner part (100) which is rotatably mounted on the inner part (100).

4. Drive (1) according to one of claims 1 to 3, characterized by the fact thatin a state installed in the hull of a watercraft, it is movable between a retracted rest position and an extended working position, wherein the drive (1) in the extended working position is extendable to such an extent that the at least one inlet channel (14) and the at least one outlet nozzle (15) project beyond the hull of the watercraft.

5. Drive (1) according to one of claims 1 to 4, characterized by the fact that the inner part (100) is connected to a flange (18) for fixing in the watercraft.

6. Drive (1) according to claim 5, characterized by the fact that the flange (18) is fixed to the watercraft via elastically compliant shock bearings.

7. Drive (1) according to any one of claims 1 to 6, characterized by the fact that the inner part (100) is limited by a deflecting arch (16) to reverse the flow direction of the water drawn in via the inlet channel (14) by the impeller (13) and accelerated towards the at least one outlet nozzle (15).

8. Drive (1) according to any one of claims 1 to 7, characterized by the fact that the inner part (100) comprises a pot-shaped receiving chamber (107) separated from the water guided by the drive (1), in which the stator (11) is fixedly inserted with the rotor (12) arranged to rotate therein.

9. Drive (1) according to any one of claims 1 to 7, characterized by the fact that the stator (11) is fixedly connected to the inner part (100) via retaining struts (102) and electrical connecting lines of the stator (11) run along or inside the retaining struts (102) from the inner part (100) to the stator (11).

10. Drive (1) according to claim 9, characterized by the fact that the retaining struts (102) are shaped in such a way that they counteract a swirl induced by the accelerated water from the impeller (13).

11. Drive (1) according to one of claims 9 or 10, characterized by the fact that the retaining struts (102) are arranged at equal or different distances from each other.

12. Drive (1) according to one of claims 9 to 11, characterized by the fact that the retaining struts (102) have the same or different cross-sections.

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