EP2109565B1 - Jet propulsion - Google Patents

Abstract

The jet propulsion comprises two or more units which are arranged axially one behind the other. The unit has a rotor (3,4) without a hub, on which internal circumference rotor blades (1,2) are fixed. A housing (9,10) is provided in which the rotor is mounted such that it can rotate. The rotor is surrounded by an electric motor with a rotor ring (5,6) and a stator ring (7,8). The rotor ring is connected to the rotor such that they rotate together. The bearing between the rotor and the housing has carbide e.g. silicon carbide or aluminum carbide.

Description

The invention relates to a jet propulsion, in particular for watercraft. On WO 2005/049420 will be referred.

In such jet drives a plurality of rotor blades are arranged on the inner circumference of the rotor, which extend up to the region of the axis of rotation of the rotor and leave there a space. The free ends of the rotor blades thus do not touch, and there is no hub provided. Furthermore, such a jet drive comprises a housing in which the rotor is rotatably mounted. The rotor is associated with an electric motor with rotor ring and stator ring. Rotor ring and stator are arranged coaxially with the rotor, and the rotor ring is rotatably connected to the rotor.

Such jet drives have numerous advantages over conventional jet drives. They are of relatively simple construction, therefore inexpensive to manufacture, and also have a relatively low efficiency. Nevertheless, such jet drives can be improved, in particular as far as the efficiency is concerned.

The invention has for its object to design a jet drive of the type mentioned in such a way that the efficiency compared to previously known jet drives of this type is improved.

This object is solved by the features of claim 1.

Accordingly, a jet drive of the known type is carried out in a tandem arrangement. In this case, two rotors are used and two electric motors, which are each arranged axially adjacent to each other as a unit. It can be provided a single housing that encloses the two units in the axial direction.

The tandem arrangement results in a higher energy yield during operation. The efficiency is thus greater than in a single jet propulsion with only a single unit of rotor and electric motor. In addition, the tandem design according to the invention is more flexible in operation. So you do not have to operate both units at the same time. Rather, one or the other unit can be switched off or then switched on.

According to another idea, a special rule is provided. This allows the speeds of the rotors of individual units to be controlled independently of each other. It can thus be selected for any driving conditions, the rotational speeds of the rotors of individual units, that is guaranteed for the overall system torque. This makes it possible to optimize the efficiency for any driving conditions. It is possible to achieve an efficiency maximum for the entire system.

This is particularly advantageous for a ship whose operating conditions are greatly changed.

In the case of fast-moving vessels, the following control is also possible: A load shift from a front to a rear rotor can be made with increasing speed. The increase in pressure experienced by the rear propeller minimizes the risk of cavitation.

It is also possible to run the rear axial bearing of a front rotor seen in the direction of travel against the front thrust bearing of a rear rotor in the direction of travel. As a result, a higher relative speed can be achieved in the camp. Bearing size and construction costs can be reduced.

Figur 1

zeigt einen Strahlantrieb in einer achssenkrechten Ansicht.

Figur 2

zeigt den Gegenstand von Figur 1 in einem Axialschnitt, und zwar gemäß der Schnittlinie A - A in Figur 1.

Figur 3

zeigt wiederum einen Axialschnitt durch einen Strahlantrieb mit zwei Einheiten im Ausschnitt.

Figur 4

zeigt in einer perspektivischen, vergrößerten Darstellung einen Ausschnitt aus dem Lagerbereich.

The invention is explained in more detail with reference to the drawing. The following is shown in detail:

FIG. 1

shows a jet propulsion in an axially perpendicular view.

FIG. 2

shows the item of FIG. 1 in an axial section, according to the section line A - A in FIG. 1 ,

FIG. 3

again shows an axial section through a jet drive with two units in the cutout.

FIG. 4

shows in a perspective, enlarged view a section of the storage area.

FIG. 1 shows the leaves 1 of the rotor of the first of the two units. In this case, there are seven leaves. But it could also be more or less. As you can see, the free ends of the leaves point to the center of the jet unit, leaving a space between the free ends.

Out FIG. 2 you realize that these are two units. It can also be seen from some of the leaves of the two jet units, namely again leaves 1 of the first unit and leaves 2 of the second unit.

Each unit comprises the following components: a rotor 3 or 4, on which the blades 1 and 2 are fixed, a rotor ring 5 and 6 and a stator 7 and 8, respectively, which is embedded in a housing 9 and 10 respectively. In addition, one recognizes the foot 1.1 or 2.1 of the single sheet.

All of these components, thus foot of the blade, rotor 3 and 4, rotor ring 5 and 6 and stator 7 and 8 are arranged coaxially to each other. The rotor ring is rotatably connected to the rotor. There is an air gap of minimal width between the rotor ring and the stator ring.

The two housings 9, 10 could also consist of a single part.

Between the two units, a spacer flange 11 is provided. At the outer ends of the two housings, in turn, a bearing flange 12 or 13 is provided.

The axial distance between the two rotors should be as small as possible. It is therefore desirable to dimension the said spacer flange 11 in the axial direction as small as possible. It could for example consist of a very thin sheet, which is only a few millimeters thick, for example 1 to 3 mm, or less than 1 mm, for example 0.5 to 1.0 mm.

The axial distance should generally be less than 10 percent of the axial rotor size.

The two electric motors are designed so that they rotate in opposite directions. This is structurally well feasible in the design of the jet propulsion system chosen here, because this unit is hullless.

The tandem design according to the invention has great advantage in terms of efficiency. This is much higher than with a correspondingly sized single jet propulsion.

FIG. 3 shows details of another embodiment of the jet propulsion system according to the invention somewhat more precisely. The rotor blades are omitted for greater clarity. It can be seen again the two rotors 3 and 4, with these rotatably connected rotor rings 5 and 6 and the stator 7 and 8, respectively. The whole is enclosed by a housing 9 and 10 respectively.

The bearings play an important role. The jet engine is completely flooded. The bearings are made of seawater-proof carbide. The structure of the bearings can be seen out FIG. 4 , See there the bearing segments 14, 15 which are embedded in the housing 9 and 10 respectively. The bearing segments 14, 15 are dovetail-shaped in cross-section, and the housing has corresponding recesses.

Depending on whether a flushing is provided on the housing bearing or not, the bearing segments 14, 15 can be arranged at a certain mutual distance d.

If this is the case, the grooves between the bearing segments are constantly flushed through, which means additional cooling of the bearing of the electric motor.

Two or more units can be connected axially in series. There are thus also three or four or more units into consideration.

LIST OF REFERENCE NUMBERS

1

rotor blade

1.1

Foot of the rotor blade

2

rotor blade

2.1

Foot of the rotor blade

3

rotor

4

rotor

5

rotor ring

6

rotor ring

7

stator

8th

stator

9

casing

10

casing

11

spacer flange

12

Lagerflansch

13

Lagerflansch

14

bearing segments

15

bearing segments

Claims (6)

1. A jet propulsion

   1.1 including two or several units axially arranged behind one another;

   1.2 each unit presents the following components or features:

   - a hubless rotor (3, 4), to whose inner periphery rotor blades (1, 2) are fixed

   - a casing (9, 10), wherein the rotor (3, 4) is rotatably mounted;

   - each rotor (3, 4) is enclosed by an electric motor with rotor ring (5, 6) and stator ring (7, 8);

   - the rotor ring (5, 6) is torque-proof connected with the rotor (3, 4);

   1.3 both electric motors are designed for opposite rotation directions.
2. A jet propulsion according to claim 1, characterised in that the bearing assembly between rotor (3, 4) and casing (9, 10) includes seawater proof carbide, preferably silicon carbide or aluminium carbide.
3. A jet propulsion according to one of the claims 1 or 2, characterised in that the bearing assembly between rotor (3, 4) and casing (9, 10) exclusively consists of carbide.
4. A jet propulsion according to any of the claims 1 to 3, characterised in that the bearing assembly consists of slide bearings.
5. A jet propulsion according to one of the claims 1 to 4, characterised in that the rotation speeds of the rotors (3, 4) of the units are adjustable independently of one another.
6. A jet propulsion according to one of the claims 1 to 5, characterised in that the rear axial bearing of a front propeller, as seen in driving direction, runs against the front bearing of a rear propeller as seen in driving direction.

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