WO2011090421A1

WO2011090421A1 - A shaft and controllable pitch propeller assembly for a marine vessel

Info

Publication number: WO2011090421A1
Application number: PCT/SE2011/050025
Authority: WO
Inventors: Jan-Olov FORSSTRÖM
Original assignee: Rolls-Royce Aktiebolag
Priority date: 2010-01-19
Filing date: 2011-01-12
Publication date: 2011-07-28
Also published as: EP2526016A1; EP2526016A4

Abstract

This invention relates to a shaft for a propeller assembly for a marine vessel, said shaft (1) arranged to provide torque to a propeller having a plurality of flanged blades via a hub (2), said hub (2) having mounting seats (3) circumferentially and equiangularly spaced from one another to provide mounting of the blades, wherein the shaft (1) has an extended end with an enlarged portion (21) forming the hub (2), wherein the diameter of said extended portion (21) is substantially larger than the diameter of the shaft (1).

Description

A SHAFT AND CONTROLLABLE PITCH PROPELLER ASSEMBLY FOR A MARINE VESSEL

TECHNICAL FIELD

The present invention relates to a shaft and propeller assembly for a marine vessel, in which the propeller has a plurality of flanged blades and a hub, to which the blades are attached circumferentially and equiangularly spaced from one another in a manner permitting setting a pitch of the blades.

BACKGROUND ART

The field of the invention relates to various kinds of propellers, i.e. fixed propeller blades (s.c. FBP), adjustably fixed propeller blades (s.c. ABP), and controllable pitch propeller. However, in the following, the description mainly refers to controllable pitch propellers, which should not be construed in a limiting manner. Controllable pitch propellers of various types have been proposed and used in the past in marine vessels, for example. In the usual controllable pitch propeller, the propeller blades are rotatably mounted on a hub and are coupled to a blade pitch control mechanism, which selectively turn the blades about their mounting axes to vary their pitch and set them at a desired pitch. Also a variety of forms of pitch control mechanisms applying mechanical, electro-mechanical, and hydraulic principles have been suggested. The propeller is driven by a shaft having an end provided with a flange, to which the body of the propeller hub is secured. An illustrative example of a controllable pitch propeller having a hub body fixed to a flanged end of a drive shaft is disclosed in US 3,501,251 (K. Haglund et al). A more recent example is disclosed in US 4,781,533 (Andersson). In both of these cases, the main interest is directed to the pitch control mechanism, and the hub body that usually is made of bronze is fixed by screws to the flanged end of the drive shaft.

However, a hub body of bronze is an expensive component usually made by casting, and may require repairing by welding to fix casting defects. Also the screw joint between the flange and the hub body is an expensive solution in relation to the total cost of the shaft and propeller assembly. SUMMARY OF THE INVENTION

The main object of the present invention is to eliminate the bronze hub body and the screw joint between shaft and hub body, which is achieved by means of a shaft according to claim 1. Thanks to the invention the manufacturing costs, may be significantly reduced.

Further advantages according to the invention will become apparent from the detailed description and also from the dependent claims which are appended.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in more detail with reference to preferred embodiments and the appended drawings, wherein,

Fig. 1 shows a cross-sectional view of a preferred embodiment according to the invention,

Fig. 1A shows a detailed view of the encircled area in Fig. 1,

Fig. 2 shows a cross-sectional view of a second embodiment according to the

invention,

Fig. 3 shows a cross-sectional view of a third embodiment according to the

invention,

Fig. 4 shows a cross-sectional view of a fourth embodiment according to the

invention,

Fig. 5 shows a cross-sectional view of a fifth embodiment according to the

invention,

Fig. 6 shows a cross-section along line VI - VI in Fig. 5, and,

Fig. 7 shows a cross-sectional view of a sixth embodiment according to the

invention.

DETAILED DESCRIPTION

In Fig. 1 there is shown perspective cross-sectional view of a preferred embodiment of a shaft 1 according to the invention. There is only shown the upper half and the outer part of the shaft 1, which is arranged with a central passage 12, for supply of power or hydraulic oil to the pitch adjusting mechanism (not shown). Integrally with the shaft 1 there is a radially extending ring 20, which forms the base for a tubular portion 21 that extends generally coaxially with the centre of the shaft 1. The tubular portion 21 extends a distance further than the end 13 of the shaft 1 to form a circular space 6 within said tubular portion 21. A stub portion 11 of the shaft 1 protrudes into the space 6 of the tubular portion 21, which stub shaft 11 provides a support surface 14 at one end of the space 6 for the pitch adjusting mechanism. The stub shaft 11 has a length that is less than half of the length of the tubular portion 21.

At the outer surface of the tubular portion 21 there are formed a plurality of the circular recesses 3 forming seats for propeller blades 9. Each seat 3 is formed by first outer cylindrical wall 32 and a bottom portion 30, 33, 34. The bottom 30, 33, 34 extends a limited distance from said wall 32 to form the outwardly facing support surfaces for the propeller. Preferably a seal 35 is arranged in conjunction with the lower portion of said wall 32, by means of arranging a groove 33 (to position said seal 35) by means of an annular wall 34 that protrudes outward in relation to the lower bottom surface 30 i.e. the wall 34 forms one of the sides for said groove 33. Accordingly the bottom portion of each propeller blade will have a step like shape to inter fit, with the inner, lower part 30 and the outer higher part 34, 35 of the bottom respectively. At the centre of each seat 3 there is arranged a relatively wide through passage 31 for inter fitting parts (not shown), of the adjusting mechanisms.

At the outer axial end of the tubular portion 21 there is arranged an annular recess 22 for inter fit with a first, intermediate end cover member 4. Said first end cover 4 extends radially inwardly and presents a circular through passage 40 at its centre for supporting the pitch adjusting mechanisms at the other end of said inner space 6. To provide a sufficiently long support surface 40 the intermediate end cover member 4 has its thickest part in the area of through passage 40, by having an extended portion 42 protruding in a direction into said closed space 6. Moreover there is a groove 41 for a sealing in said support surface 40.

The outer end cover 5 is cup shaped to provide a further space 7 between the

intermediate member 4 and an annular edge 50 within the outer end cover 5, which space 7 is intended for fixedly attaching the power providing part (not shown) of the adjusting mechanism (not shown). In the preferred embodiment the power providing mechanism is clamped into a fixed position between the annular edge 51 of the outer end cover 5 and an annular edge 43 facing in the opposite direction at the intermediate member 4. The annular edge 43 also preferably provides a circular edge 43 A for inter fit with the base portion 51 of the outer end cover 5. Thanks to the design of the different support members of the hub 2, 4, 5, 11 it is possible to easy fit the adjusting mechanism, despite the fact that the main portion 20, 21 of the hub 2 is fixed to the shaft 1. Accordingly the first part of the adjusting mechanism is first fitted onto the stub shaft 11 and its intermediate parts mounted in the first space 6, which is possible thanks to the large inner diameter (at least 1,5 times the outer diameter of the shaft 1, preferably at least 2 times) at rear end of the tubular portion 21. Thereafter the first end cover member 4 is fixed into the recess 22 of the tubular member 21 providing the intermediate support surface 40 for the force transmitting member (not shown) extending from the outer most space 7 into the inner space 6 of the pitch adjusting mechanism. In a third step the power supplying part (not shown, e.g. electric motor or hydraulic motor) is clamped into a fixed position between the edge 50 of the outer end cover 5 and the annular ring 43 of the intermediate member.

In Fig. 2 there is shown the same kind of cross-sectional view as in Fig. 1, of a further embodiment in accordance with the invention. In this embodiment the parts that are integral with the shaft 1 are exactly the same as already described in relation to Fig. 1 and will therefore not be described more in detail. In the following merely differing features will be described. The main difference is that the intermediate end cover 4 according to this embodiment also is arranged with a portion that extends axially, rewardly to extend all the way to provide for the space 7 for the power providing part of the adjusting mechanism. Accordingly one can say that the intermediate member 4 in this embodiment has taken over one further function that according to the embodiment in Fig. 1 was provided by the outer end cover 5. As a consequence the outer end cover in this embodiment is smaller and merely presents the cup shaped outer part of the end cover. In Fig. 3 there is shown a further embodiment according to the invention having most of its part as already described in Fig. 1 and Fig. 2. The only differing part is the outer end cover 5 in this embodiment is made of two parts, wherein the fixing ring 53 is made in a much thicker material and the outer cup shaped portion 54 is made in a thin sheet like material that may be easily formed by pressing to a desired form and finally welded on to the fixing ring 53.

In Fig. 4 there is shown at further embodiment in accordance with the invention. It is to be noted that the design aspects regarding the tubular member 21 and the intermediate member 4, and the stub shaft 11 are exactly the same as described in connection with Fig.1. The main difference with this embodiment is that a clamp connection 8 is being used to attach the hub 2 to the shaft 1. Accordingly in this embodiment the hub 2 is not an integral part of the main shaft portion 1 , but a separate part that by means of the clamping connection 8 is fixedly attached to the shaft 1 at later stage. Any known kind of known clamp coupling may be used, e.g. the so called OK coupling supplied by SKF.

The shrink fit clamp coupling suitably is of the type having a thin inner sleeve with a tapered outer diameter fitted on the main portion of the shaft, a thick outer sleeve formed by the generally tubular portion and having a matching tapered inner surface, an inlet for injection of a hydraulic medium between the sleeves, and a built-in hydraulic jack for driving the outer sleeve up the taper of the inner sleeve. The integrally formed shaft 1 and hub 2 may be produced in different ways, e.g. by forging and subsequent machining, e.g. by turning.

The shaft 1 and the generally tubular portion 2 may beneficially be made of stainless material. To keep cost for material on a moderate level the length of said shaft 1 may be limited by having the whole shaft device, divided into a first, outboard shaft 1 portion connected to a second, inboard shaft portion (not shown), and especially so by arranging the inner end of the expensive, stainless shaft portion 1 to interfit with a coupling attached adjacent the passage for said shaft 1 through the hull (not shown). Hence the second, inboard shaft, may then be made in a less costly, non stainless material, to reduce the total cost for the whole shaft device.

In another embodiment, the generally tubular portion is made of non-stainless material, having chosen surfaces covered with a layer of a corrosion protective impact resistant material. The corrosion protective material may suitably be zinc or nickel applied by brush electroplating, or "coating" applied by brush or by spraying. Alternatively, the corrosion protective impact resistant material is stainless material applied by welding. Suitably, the corrosion protective impact resistant layer has a thickness of 3-5 mm.

In Fig. 5 there is shown the same kind of cross-sectional view as in Fig. 1, of a further embodiment in accordance with the invention. In this embodiment the enlarged portion 21that is integral with the shaft 1 is homogenous, i.e. there is no use of any internally arranged pitch adjusting mechanism, but the propeller blades are either fixed (FBP) or need to be manually adjusted (ABP), by means of attachment bolts and slit holes that allow repositioning/adjustment of the pitch angle of each blade 9 within the seats 3.

Fig. 6 is a cross-sectional view along VI -VI in Fig. 5. Fig. 7 shows the same kind of cross-sectional view as in Fig. 5, of a further embodiment in accordance with the invention, wherein the inner core of the enlarged portion is hollow, i.e. to attach with bolts from the inner core side, which allows for use of a continuous/smooth upper flange surface of the propeller blades and also reduces the amount of material needed. In other aspects this embodiment is exactly the same as already described in relation to Fig. 1 (use of end cover 4) and Fig. 5 (attachment of propeller blades 9) and will therefore not be described more in detail.

The invention is not limited by what that is described above but maybe wear it within the scope of the impendent claims. For instance it is evident that skill person may use a separate portion 11 for the stub shaft, e.g. which is welded on to place at the latest age.

Claims

1. A shaft for a propeller assembly for a marine vessel, said shaft (1) arranged to

provide torque to a propeller having a plurality of flanged blades via a hub (2), said hub (2) having mounting seats (3) circumferentially and equiangularly spaced from one another to provide mounting of the blades, characterised in that the shaft

(1) has an extended end with an enlarged portion (21) forming the hub (2), wherein the diameter of said extended portion (21) is substantially larger than the diameter of the shaft (1).

2. A shaft according to claim 1 , characterised in that the enlarged portion (21) is in the form of a generally tubular portion (21) forming the hub (2), an end cover (4, 5) closing said generally tubular portion so as to form a closed space (6) in the generally tubular portion (21), and preferably that there is an annular grove (22) at the inner side of the end portion of the said tubular portion (21) arranged to inter fit with the said end cover (4, 5).

3. A shaft according to claim 2, characterised in that and that there is a radial extending portion (20) connecting the tubular portion (21) with the shaft (1).

4. A shaft according to any preceding claim, characterised in that said

mounting seats (3) have a first outwardly facing support surface (30) and in connection therewith an annular grove (33) for housing a sealing device (35).

5. A shaft according to any preceding claim, characterised in that the length of said shaft (1) is limited by having its inner end arranged to interfit with a coupling attached to a second, inner shaft, by means of having said coupling arranged adjacent the passage for said shaft (1) through the hull.

6. A shaft according to claim 5, characterised in that the shaft (1) and hub (2) is made in one integral unit, made of stainless material.

7. A shaft according to claim 6, characterised in that the shaft (1) and hub (2) is made in one integral unit of non-stainless material, covered with a layer of a corrosion protective, impact resistant material.

8. A shaft according to claim 7, characterised in that the corrosion protective impact resistant layer has a thickness of 3-5 mm.

9. A shaft according to any of claims 2-8, characterised in that said generally tubular portion (21) is arranged to house equipment for adjusting the pitch of the blades, of a controllable pitch propeller.

10. A shaft according to claim 9, characterised in that the shaft ( 1 ) is arranged with an extended stub shaft portion (11) that protrudes into the space (6) within the tubular portion (21).

11. A shaft according to claim 10, characterised in that stub shaft portion (11) is arranged with a peripheral surface (14) arranged to support the equipment for adjusting the pitch.

12. A shaft to any of claims 9-11, characterised in that the inner diameter of tubular housing (21) at the end thereof is arranged to enable insertion of said equipment for adjusting the pitch into said closed space (6).

13. A shaft according to any of claims 9-12, characterised in that a further

support surface (40) is arranged in the end cover (4, 5) to support equipment for adjusting the pitch, preferably in the form of an interior surfaces of a circular passage.

14. A shaft according to any o f claims 9-13, characterised in that said end cover (4, 5) is formed by a first intermediate member (4) and a second outer member (5), wherein said first intermediate member (4) extends radially inwardly to form an annular space (7) there between and the outer member (5).

15. A shaft as claimed in any of claims 9-14, characterised in that the generally tubular portion (2) is fixed to a main portion of the shaft (1) by means of a shrink fit clamp coupling (8).