WO2019020618A1

WO2019020618A1 - Cradle structure for ship propulsion apparatus, and ship propulsion apparatus

Info

Publication number: WO2019020618A1
Application number: PCT/EP2018/070026
Authority: WO
Inventors: Ning Jiang; Li Cheng ZHANG; Rui Chun DUAN; Chang Sheng YANG; Wil Van Mol; Fu Hua QIU
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-07-24
Filing date: 2018-07-24
Publication date: 2019-01-31
Also published as: CN109292067A

Abstract

The present invention provides a cradle structure (50) for a ship propulsion apparatus (100), and a ship propulsion apparatus, the cradle structure being used for connecting an electric drive unit (40) of the ship propulsion apparatus to a hull (200), wherein the cradle structure comprises: a first end (56), for connecting to the hull (200) in a mutually rotatable manner; a second end (58), wherein the second end (58) comprises: a first support foot (51), connectable to a housing (44) of the electric drive unit (40) at a far-end region (41) remote from a propulsion device of the electric drive unit (40), and a second support foot (52), connectable to the housing (44) of the electric drive unit (40) at a near-end region (42) close to the propulsion device, with the first support foot (51) and the second support foot (52) being spaced apart from one another, and a gap part (53) being formed between the first support foot and the second support foot.

Description

Cradle structure for ship propulsion apparatus, and ship propulsion apparatus

Technical field

The present invention relates to a cradle structure for a ship propulsion apparatus, used for connecting an electric drive unit of the ship propulsion apparatus to a hull; and also relates to a ship propulsion apparatus, in particular to a nacelle-type propulsion apparatus for a ship .

Background art A ship propulsion apparatus is an apparatus which provides motive power for a ship. Ship propulsion devices may be divided into two types, active and reactive, according to their mode of action. Towropes and sails (see sailboat) etc. which rely on manpower or windpower to drive a ship forward are active; oars, sculls, paddle wheels, hydrojet propulsion devices and screw propellers etc. are reactive. Most modern transport ships use reactive propulsion devices, with screw propellers being the most widely used. A conventional screw propeller is connected to an engine in the hull by means of a through-running shaft at a tail part, and cooperates with a rudder to achieve propulsion and steering of the hull. A nacelle-type screw propeller propulsion device may be mounted on a ship propulsion apparatus separate from a shell of the ship. Such a structure enables the entire ship propulsion apparatus to rotate, and through such rotation it is possible for fluid of the screw propulsion device to be guided in the direction required for movement of the ship, so that screw propeller and rudder are combined in a single unit, thereby achieving effects such as improved efficiency, convenience of operation and space saving in the hold. When a nacelle-type screw propeller propulsion device is used as a source of motive power for the ship propulsion apparatus, the thrust of the screw propeller will be transferred to the hull, and considerable stress will arise at a slew bearing plate of the propulsion apparatus and at a support-electric machine connection point as the ship is propelled forward. Moreover, since an electric machine of the driving screw propeller will generate a large amount of heat during operation, an important channel for carrying away this heat is conduction of the heat via a stator to a casing of the propulsion apparatus exposed to seawater. However, in previous nacelles of the full-coverage type, there would be a large region which could not be cooled, causing high temperatures to arise locally. To solve this problem, it is necessary to add a complex air circulation cooling apparatus in a nacelle cradle part.

Content of the invention

To solve one or more of the problems mentioned above, the present invention first of all proposes a cradle structure for a ship propulsion apparatus, used for connecting an electric drive unit of the ship propulsion apparatus to a hull, wherein the cradle structure comprises: a first end, for connecting to the hull in a mutually rotatable manner;

a second end, wherein the second end comprises:

a first support foot, connectable to a housing of the electric drive unit at a far-end region remote from a propulsion device of the electric drive unit,

a second support foot, connectable to the housing of the electric drive unit at a near-end region close to the propulsion device, the first support foot and the second support foot being spaced apart from one another, and a gap part being formed between the first support foot and the second support foot.

The cradle structure according to the present invention can be used for propulsion apparatuses of ships of many types, especially nacelle-type propulsion apparatuses; the design of the first support foot and the second support foot of the cradle enables the housing of the electric drive unit to be at least partially exposed to water when the cradle structure is connected to the housing of the electric drive unit, so that cooling can be performed via the housing. In addition, the first support foot and the second support foot can be connected separately at two ends of the housing of the electric drive unit, thereby solving the problem of insufficient stability caused by an L-shaped connection, and can absorb stress at the points of connection with the electric drive unit to the greatest extent possible .

According to an advantageous embodiment, the cradle structure comprises a cradle shell and an inner cavity enclosed by the cradle shell. A hollow structure can reduce weight, and the inner cavity may be further used for cooling.

According to an advantageous embodiment, the gap part is disposed such that at least a part of the housing between the near-end region and the far-end region of the housing of the electric drive unit is not covered by the cradle shell.

According to an advantageous embodiment, a cross section of the cradle shell in a water flow direction is streamlined, or a cross-sectional shape of the cradle shell gradually widens towards a rear end from a front end in a direction of travel and then gradually narrows towards a rear end in the direction of travel. With such a design, the cradle structure has low travelling resistance in water flow .

According to an advantageous embodiment, the first support foot and/or the second support foot of the cradle shell is/are hollow, such that the inner cavity of the cradle structure can be in communication with an internal space of the electric drive unit by means of the first support foot and the second support foot. When an inner cavity of the cradle shell is in communication with an inner cavity of the housing of the electric drive unit, the inner cavity of the cradle shell may be used to further cool the electric machine, i.e. the cooling area and other possibilities for cooling are further increased .

According to an advantageous embodiment, the first end is connectable to the hull in a mutually rotatable manner by means of a swivel bearing plate or a mating ring. Steering of the propulsion apparatus can thereby be ensured.

According to an advantageous embodiment, an end of the first support foot and/or the second support foot is open; communication can thereby be established between the inner cavity of the cradle shell and the inner cavity of the housing of the electric drive unit by means of the first support foot and/or the second support foot.

Another aspect of the present invention proposes a ship propulsion apparatus, comprising:

an electric drive unit, comprising an electric machine and a housing enclosing the electric machine;

a propulsion device, driven by the electric machine;

and a cradle structure as described in any one of the embodiments above, wherein the cradle structure is connected to the electric drive unit. In this way, a ship propulsion apparatus having good cooling and being securely connectable to a ship can be provided.

According to an advantageous embodiment, an air cooling apparatus is disposed in the housing. Advantageously, the cooling apparatus may be a fan, disposed on an electric machine shaft of the electric machine, so that air circulation in the inner cavity of the cradle structure and the inner cavity of the housing of the electric drive unit can be used to achieve further cooling.

According to an advantageous embodiment, the housing is connected to a cradle shell of the cradle structure, such that an inner cavity of the housing is in communication with an inner cavity of the cradle shell. When an inner cavity of the cradle shell is in communication with an inner cavity of the housing of the electric drive unit, the inner cavity of the cradle shell may be used to further cool the electric machine, i.e. the cooling area and other possibilities for cooling are further increased.

Description of the accompanying drawings

The accompanying drawings below are merely intended to illustrate and explain the present invention schematically, without limiting the scope thereof, wherein:

Fig. 1 shows schematically a nacelle-type propulsion apparatus according to the prior art .

Fig. 2 shows schematically another nacelle-type propulsion apparatus according to the prior art.

Fig. 3 shows schematically a nacelle-type propulsion apparatus according to an embodiment of the present invention.

Fig. 4 shows a schematic diagram of section IV-IV.

Fig. 5 shows schematically a nacelle-type propulsion apparatus according to an embodiment of the present invention, viewed from another angle .

Fig. 6 shows schematically another nacelle-type propulsion apparatus according to an embodiment of the present invention.

Fig. 7 shows schematically another nacelle-type propulsion apparatus according to an embodiment of the present invention. Particular embodiments

To enable clearer understanding of the technical features, objectives and effects of the invention, particular embodiments of the present invention are now explained with reference to the accompanying drawings .

Fig. 1 shows schematically a nacelle-type propulsion apparatus according to the prior art. The propulsion apparatus is mounted to a lower part of a hull and comprises an electric machine unit 1 having a housing structure. The electric machine unit 1 is mounted on a cradle 3, which is rotatably connected to the bottom of the hull by means of a mating ring 4. A screw propulsion device 5 or screw propeller 5 is mounted at an upstream end 2 of the electric machine unit 1. A connection with the cradle 3 is accomplished at a downstream end corresponding to the upstream end 2 by means of a so-called lower part 6. The lower part 6 is provided with a mounting hole 8 for a fastening bolt. Water flowing into the lower part 6 flows in the direction of the electric machine unit 1 and cools an electric motor unit.

In the embodiment shown in the prior art, the cradle 3 and the electric machine unit 1 form an L-shaped structure, such that an outer wall of the electric machine unit 1 can be exposed to water over a larger range, to facilitate cooling. However, due to the L-shaped structure, a connection structure between the electric motor unit 1 and a wall member 3 is not as rigid as a suspension arm of the full-coverage type (a prior art solution as shown in fig. 2) . A large cantilever structure thereof will also cause a large torque at a bend, so the design must incorporate an increase in thickness.

Fig. 2 shows schematically another nacelle-type propulsion apparatus according to the prior art. A lower end of a cradle 3 of the propulsion apparatus extends in a longitudinal direction of the electric machine unit 1, and is connected thereto, and a robust connection between a suspension arm and the electric machine unit is thereby provided. Such a manner of connection enables the problem of stress and the problem of water flow specification to be solved. However, due to such a "full-coverage" manner of connection, an outer wall of the electric machine unit cannot be completely exposed to water so as to be cooled sufficiently; in this prior art, a special water cooling system 15 is designed in the suspension arm 3. This will inevitably further increase manufacturing difficulty and costs.

In order to enable such a nacelle-type propulsion apparatus to be more sturdy, and at the same time ensure a good cooling effect for the electric machine unit, the present invention proposes a specific solution .

Fig. 3 shows schematically an embodiment of a ship propulsion apparatus 100 according to the present invention.

The ship propulsion apparatus 100 is in particular a nacelle-type ship propulsion apparatus, which in general can be connected to a ship, in particular the bottom of a ship, by means of a component known in the art such as a slew bearing plate 30 or mating ring, such that the nacelle-type ship propulsion apparatus 100 can rotate, and thereby adjust the ship's navigation direction. The ship propulsion apparatus 100 as shown in fig. 3 comprises an electric drive unit 40; the electric drive unit 40 comprises a housing 44, and a drive component such as an electric machine enclosed within the housing 44. The structure of the electric machine is known in the art, so is not described superfluously here. A propulsion device 60, generally a screw propulsion device or screw propeller 60, is provided on one end 42 of the electric drive unit 40. In the embodiment shown in fig. 3, the screw propeller 60 comprises four specially designed vanes 62. Obviously, the number of vanes could also be 3 or 5, and the vane shape thereof must be designed according to the actual thrust, etc. In the present invention, a region of that end of the electric drive unit 40 which is close to the screw propeller 60 may be called a near-end region 42. This is not limited to that point which is closest to the screw propeller 60, but may indicate a region on the electric drive unit 40, in particular the housing 44 thereof, which is closer than another end is to the screw propeller 60. Correspondingly, a region on the electric drive unit 40, in particular the housing 44, which is closer to the other end, or a region which is remote from the screw propeller 60, is called a far-end region 41.

The ship propulsion apparatus 100 further comprises a cradle structure 50 connecting the electric drive unit 40 to the slew bearing plate 30. The cradle structure as shown in fig. 3 forms an approximately triangular shape when viewed at the visual angle of the drawing . A bearing end 56 thereof close to the slew bearing plate 30 has a smaller cross section capable of mating with the slew bearing plate 30. A body 55 of the cradle structure 50 extends in the direction of the electric drive unit 40 from the bearing end 56. The body 55 is enclosed by a cradle shell 54 to form a hollow structure. Fig. 4 also schematically shows a sectional view of the body 55 visible along the cut line IV-IV in fig. 3. Clearly, a cross-sectional area of an inner cavity 57 therein, or a cross-sectional size of the body 55, gradually expands from the bearing end 56 towards an electric machine unit end, until two support feet spaced apart from one another are formed at the electric machine unit end. The cradle shell 54 is modelled in such a way that the cross section of the cradle structure 50 is streamlined in the direction of water flow. One of the support feet, namely a first support foot 51, is connected to the housing 44 of the electric drive unit 40 at the far-end region 41 which is axially remote from the screw propeller; the other support foot, namely a second support foot 52, is for connecting to the housing 44 of the electric drive unit 40 at the near-end region 42 which is axially close to the screw propeller. Since the first support foot 51 and the second support foot 52 are spaced apart from one another, a gap part 53 is formed between the first support foot and the second support foot, and since the gap part itself is also formed by the cradle shell 54, it extends between the first support foot and the second support foot in a manner similar to a "bridge", such that at least a part of the housing 44 between the near-end region 42 and the far-end region 41 of the housing 44 of the electric machine unit 40 is not covered by the cradle shell of the cradle structure 50. Thus, such a cradle structure with "suspension at both ends" can not only retain the sturdiness of a covering-type cradle, i.e. can retain the strength thereof without the need for a heavy structure, but can also expose a large area of the housing 44 of the electric drive unit to water, thereby achieving adequate cooling. Thus, through structural improvement, the cradle structure combines advantages of an L-type suspension arm structure and a full-coverage cradle structure.

Although not shown in fig. 3, it is obvious that the housing 44 of the electric machine unit 40 could also be hollow. In addition, since the first support foot 51 and the second support foot 52 formed by the cradle shell 54 are also hollow, an inner cavity of the cradle structure 50 can be in communication with an internal space of the electric drive unit 40.

Reference is made to fig. 7, which shows a schematic diagram of an internal space of the first support foot 51, the second support foot 52, and the housing 44 of the electric drive unit 40. The electric drive unit 40 comprises an electric machine 47, supported on an electric machine shaft 43. The electric machine shaft 43 is rotatably supported on a pair of bearings 48. To achieve better cooling, as well as by means of the housing 44 of the electric drive unit having a large area exposed to water, further cooling can be achieved by mounting a small fan 49 on the electric machine shaft. The fan 49 drives air to circulate in inner cavities of the housing 44 and the cradle shell 54, as shown by the arrow 70. Of course, air could also be made to circulate in the opposite direction to that shown by the arrow 70, by mounting a fan of a different fan shape. As shown by the arrow 70, hot air between a stator and a rotor of the electric machine 42 is driven into the inner cavity of the cradle shell 54; since there are no heat-emitting components in the inner cavity of the cradle shell 54, and an outer surface thereof has a large area in contact with water, the circulating air can be cooled more quickly, and the cooled air can enter the electric machine to cool same .

The connection between the cradle shell 54 and the housing 44 of the electric drive unit 40 may be accomplished in many ways, such as by riveting, bolt connection, welding, slide-pin suspension or bonding, and is not described further here. As shown in fig. 3, the cradle shell 54 is connected to the housing 44 at the first support foot 51 and the second support foot 52 of the cradle structure 50, to form a first connection region 45 and a second connection region 46. In the embodiment shown in fig. 3, the first connection region 45 is slightly larger than the second connection region 46. However, generally speaking, since the connection regions are in fact regions of the cradle shell 54 of the cradle structure 50 which cover the housing 44 of the electric drive unit 40, the housing 44 will be cooled more effectively if the connection regions are smaller. In addition, if circulated air cooling is used, then the connection regions must be sufficiently large to arrange air channels, to ensure the effectiveness of active cooling performed by means of the fan inside the housing 44 of the electric drive unit 40. Thus, designers can design a better size and shape for the first connection region 45 and the second connection region 46 on the basis of experiments or simulation.

It must be pointed out that ends of the first support foot 51 and the second support foot 52 may be open ends (i.e. ends of the cradle shell 54 at the first support foot 51 and the second support foot 52 are open, not closed, so that communication can be established between the inner cavity of the cradle shell 54 and the inner cavity of the housing 44 of the electric drive unit by means of the first support foot and the second support foot) ; alternatively, when the ends of the first support foot 51 and the second support foot 52 are closed, cooling may be performed principally by means of the housing 44 not covered by the cradle structure, or by means of the fan. Of course, it is possible for one of the first support foot 51 and the second support foot 52 to be closed, and the other open.

Fig. 5 shows schematically another embodiment of a ship propulsion apparatus according to the present invention. As shown in the figure, a screw propeller 60' has a different form; those skilled in the art may select the screw propeller or another type of propulsion device according to the actual application environment. In this embodiment, it can be seen that a first connection region 45' and a second connection region 46' have more similar sizes; this also facilitates air circulation in the internal cavities of the cradle shell 54 and the housing 44.

Fig. 6 shows schematically another embodiment of a ship propulsion apparatus according to the present invention. A first connection region 45" and a second connection region 46" are larger, such that a gap 53" between a first support foot 51" and a second support foot 52" is smaller. The line of thinking of such a design is that greater use is made of air circulation in the internal cavities of the cradle shell 54 and the housing 44 to perform cooling. Thus, there are greater requirements for the cooling area of the cradle shell 54, and correspondingly, the connection between the cradle structure and the electric drive unit 40 is more firm.

In the various embodiments according to the present invention, an inflow-side front foot of the cradle structure 50, i.e. the first support foot, is designed to be relatively narrow, to gradually expand along a circumference thereof, and then to contract at a non-inflow side. In this way, a shape having good fluid dynamics such as a streamlined shape more conducive to water flow can be formed on an A-A cross section similar to that shown in fig. 3. The three-dimensional shape of the cradle structure 50 can be seen more clearly in fig. 5 for example.

It should be understood that although the description herein is based on various embodiments, it is by no means the case that each embodiment contains just one independent technical solution. Such a method of presentation is adopted herein purely for the sake of clarity. Those skilled in the art should consider the description in its entirety. The technical solutions in the various embodiments could also be suitably combined to form other embodiments capable of being understood by those skilled in the art.

The embodiments above are merely particular schematic embodiments of the present invention, which are not intended to limit the scope thereof. All equivalent changes, amendments and combinations made by any person skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection thereof.

List of labels used in the drawings:

1 electric machine unit

3 cradle

4 mating ring

5 screw propeller

6 lower part

8 mounting hole

15 water cooling system

16 water cooling pipeline

30 swivel bearing plate

40 electric drive unit

41 far end

42 near end

44 housing

45, 45', 45' ' first connection region

46, 46', 46' ' second connection region

47 electric machine

48 bearing

50, 50', 50' ' cradle structure

51, 51', 51' ' first support foot

52, 52', 52' ' second support foot

53, 53', 53' ' gap

54 cradle shell

55 body of cradle structure

56 bearing end of cradle structure

60, 60', 60' ' screw propeller; propulsion device

62, 62', 62' ' vane

70 circulating air path

100, 100', 100' ' ship propulsion apparatus.

Claims

1. A cradle structure (50) for a ship propulsion apparatus (100), used for connecting an electric drive unit (40) of the ship propulsion apparatus to a hull (200), wherein the cradle structure comprises: a first end (56) , for connecting to the hull (200) in a mutually rotatable manner;

a second end (58), wherein the second end (58) comprises:

a first support foot (51), connectable to a housing (44) of the electric drive unit (40) at a far-end region (41) remote from a propulsion device of the electric drive unit (40),

a second support foot (52), connectable to the housing (44) of the electric drive unit (40) at a near-end region (42) close to the propulsion device,

the first support foot (51) and the second support foot (52) being spaced apart from one another, and a gap part (53) being formed between the first support foot and the second support foot.

2. The cradle structure (50) as claimed in claim 1, characterized in that the cradle structure (50) comprises a cradle shell (54) and an inner cavity enclosed by the cradle shell (54) .

3. The cradle structure (50) as claimed in claim 2, characterized in that the gap part (53) is disposed such that at least a part of the housing (44) between the near-end region (42) and the far-end region (41) of the housing (44) of the electric drive unit (40) is not covered by the cradle shell (54) .

4. The cradle structure (50) as claimed in claim 2 or 3, characterized in that a cross section of the cradle shell (54) in a water flow direction is streamlined, or a cross-sectional shape of the cradle shell (54) gradually widens towards a rear end from a front end in a direction of travel and then gradually narrows towards a rear end in the direction of travel.

5. The cradle structure (50) as claimed in any one of claims 2 to 4, characterized in that the first support foot (51) and/or the second support foot (52) of the cradle shell (54) is/are hollow, such that the inner cavity of the cradle structure (50) can be in communication with an internal space of the electric drive unit (40) by means of the first support foot (51) and the second support foot (52) .

6. The cradle structure (50) as claimed in any one of claims 1 - 4, characterized in that the first end (56) is connectable to the hull in a mutually rotatable manner by means of a swivel bearing plate (30) or a mating ring (30) .

7. The cradle structure (50) as claimed in any one of claims 1 - 4, characterized in that an end of the first support foot (51) and/or the second support foot (52) is open.

8. A ship propulsion apparatus (100), comprising:

an electric drive unit (40), comprising an electric machine and a housing (44) enclosing the electric machine;

a propulsion device (60), driven by the electric machine;

and a cradle structure (50) as claimed in any one of claims 1 - 7, wherein the cradle structure (50) is connected to the electric drive unit (40) .

9. The ship propulsion apparatus (100) as claimed in claim 8, characterized in that an air cooling apparatus is disposed in the housing (44) .

10. The ship propulsion apparatus (100) as claimed in claim 8 or 9, characterized in that the housing (44) is connected to a cradle shell (54) of the cradle structure (50), such that an inner cavity of the housing (44) is in communication with an inner cavity of the cradle shell (54) .