GB2160618A

GB2160618A - Ship's propeller arrangement

Info

Publication number: GB2160618A
Application number: GB08514301A
Authority: GB
Inventors: Gunter Jeschkowski
Original assignee: Blohm and Voss GmbH
Current assignee: Blohm and Voss GmbH
Priority date: 1984-06-08
Filing date: 1985-06-06
Publication date: 1985-12-24
Also published as: GB8514301D0; NO852262L; NL8501655A; FI852285L; NO160500C; JPS6127795A; DE3421405A1; GB2160618B; FI852285A0; NO160500B

Abstract

A mounting for a guide wheel which is arranged behind a ship's propeller and which rotates around the axis of the propeller is characterised in that for mounting the guide wheel a bell shaft (12) with a self-aligning roller bearing (14) and a roller bearing (15) is provided in the hub (13) of the guide wheel in place of the cap (spinner) which covers the moving apparatus (8) for an adjustable propeller (10) and is protected against seawater by means of a seal (16) and a cover (17). <IMAGE>

Description

SPECIFICATION Mounting for a guide wheel in a propeller arrangement for a ship The invention relates to a mounting for a guide wheel which is arranged behind a ships propeller and which rotates around the axis of the propeller.

Such guide wheels are known for the pur pose of improving the efficiency of a ships propeller, for example from German Auslegeschrift 1 7 56 889. Furthermore, German Offenlegungsschrift 30 37 369 teaches that an improvement in the efficiency of a ships pro peller is particularly required for adjustable propellers in view of the thicker hub.

In operation the flow generated by the driven propeller, which is located in front of the guide wheel produces rotation of the bladed guide wheel and this rotation gener ates further thrust which assists the propulsion of the ship. In practice the radially inner portions of the blades of the bladed guide wheel act like a turbine whereas the radially outer portions of these blades act as a pump driven by the turbine portions, and this accounts for the thrust generated by the guide wheel.

If the necessity of a guide wheel arises with an already finished ship then it is desirable to provide a construction which is as short as possible for the arrangement of the guide wheel, so that the rudder does not have to be displaced rearwardly because of the need to accommodate the guide wheel.

Furthermore, the normal cap which is present in many cases, which closes off the adjustable propeller hub from the rear and which gets in the way of the mounting of the guide wheel, should in many cases be reusable-for example when using the propeller behind another ship.

The problem underlying the invention is to realize these two requirements, i.e. to provide a mounting for a guide wheel which is compact and short in the axial direction and which does not prevent the reuse of the propeller with the original cap.

In order to solve this problem the present invention is characterised in that, for mounting the guide wheel, a bell shaft with a selfaligning roller bearing and a roller bearing is provided in the hub of the guide wheel in place of the cap which covers the apparatus for moving an adjustable propeller and is protected against seawater by means of a seal and a cover.

The self-aligning roller bearing is preferably arranged in the hub of the guide wheel behind the roller bearing and is hydraulically secured.

The present invention also comprises a propeller arrangement for a ship comprising a first propeller, in particular an adjustable pro peller, having a hub; a shaft drivingly con nected to and extending forwardly from said hub for rotating said first propeller, a bell shaft or hollow stub shaft secured to said hub and extending rearwardly from said first pro peller for supporting a bladed guide wheel or guide propeller, with said bladed guide wheel or guide propeller, with said bladed guide wheel or guide propeller being substantially freely rotatably mounted on said bell shaft via first and second bearings comprising a first roller bearing and a second self-aligning roller bearing.

As previously mentioned the self-aligning roller bearing is preferably disposed behind said first roller bearing as viewed in the normal direction of travel of an associated ship. It is the self-aligning roller bearing which carries the thrust generated by the bladed guide wheel.

The self-aligning roller bearing preferably includes a hydraulically clampable sleeve, as known per se, for controlling the radial fit thereof. This facilitates the installation of the guide wheel, The bladed guide wheel or guide propeller has a hub for receiving said bearings and a seal is provided between said guide wheel hub and said bell shaft, or said hub of said first propeller, permitting relative rotation therebetween but preventing water reaching said bearings.

The seal preferably comprises at least two relatively rotatable seal rings and one of said seal rings is secured to said hub of said bladed guide wheel and preferably serves to secure an outer race of said roller bearing against a shoulder or spacer provided in said hub of said bladed guide wheel. A seal of this kind thus serves a double purpose, mamely the sealing of the bearings and the clamping of the inner race of the roller bearing and does not require a great deal of axial space.

The seal can conveniently by enclosed by a simple conical ring which preserves the outer stream-lined contour between the hub of the first propeller and the hub of the bladed guide wheel.

A cover is conveniently secured to the end of said hollow bell shaft and preferably assists in securing the inner race of said self-aligning roller bearing. This cover prevents seawater or bearing oil reaching the mechanism for adjusting the adjustable propeller, and can also act to lock a nut used to position the inner race of the self-aligning roller bearing.

A second cover is preferably connected to the rear end face of the hub for said bladed guide wheel and thus forms the extreme rear end of the propeller arrangement. This cover forms a very simple way of sealing the bearings against the ingress of seawater from the rear and requires very little space in the axial direction.

Finally, a spacer is conveniently provided between the inner races of the roller bearing and the self-aligning roller bearing, with the inner race of the roller bearing being clamped via said spacer against a shoulder or spacer at the axially forward end of the bell shaft. This arrangement is easy to assemble and the spacer can conveniently be machined to take up tolerances.

The invention will now be described in more detail in the following with reference to a specific embodiment as illustrated in the drawings which show: Figure 1 the arrangement of a guide wheel in accordance with the invention in relation to the shapes of the stern and of the rudder, and Figure 2 the bell shaft which carries the guide wheel together with the axially and radially acting guide wheel bearings and their seals.

Fig. 1 shows the stern 1 of the ship with a rudder vane 4 which is pivotable about the rudder axis 5 for the purpose of steering the ship and which is rotatably journalled at the top in the ships hull and is connected at the bottom with a rudder support strut 6. The ships drive in the form of an adjustable propeller 10 having the hub 11 and propeller blades 7, the centre of which is indicated by the reference numeral 9, is arranged in front of the rudder vane 4. The cap (not shown) which normally belongs to the adjustable propeller 10 has been removed from behind the propeller hub 11 and a bell shaft 1 2 flanged on in its place.The bell shaft 1 2 covers the moving apparatus 8 for the adjustable propeller 10 on the one hand and has on the other hand, been machined at the rear to form the actual bell shaft 1 2 which accommodates the mounting for the guide wheel 2 with vanes 3.

Four existing tiebolts 18 serve for the mounting. A recess 1 9 is turned into the hub 11 of the adjustable propeller in order to accommodate the bell shaft 12. A self-aligning roller bearing 14 and a roller bearing 15 were selected to accommodate the radial load and the axial thrust of the guide wheel 2 with hub 1 3. The mounting of Fig. 2 is characterised in that the self-aligning roller bearing 1 4 is arranged at the rear as a result of the short construction of the overall arrangement. Because of this a self-aligning roller bearing 14 with hydraulic clamping sleeve was necessary.

The self-aligning roller bearing 14 and the roller bearing 1 5 have an interference fit in the outer ring for the guide wheel 2. This measure ensures reliable installation and removal of the guide wheel 2. A cover 1 7 is provided at the rear for the purpose of sealing between the bell shaft 2 and the hub 13 of the guide wheel. A seal 1 6 which must be mounted on the hub 1 3 of the guide wheel before mounting the guide wheel on the bell shaft 1 2 was developed at the front in connection with the short construction. The running sleeve 20 of the seal 1 6 simultaneously clamps the outer ring of the roller bearing 1 5.

The housing 21 is of split construction to accommodate the seal rings of the seal 1 6 and is bolted onto the bell shaft 1 2 in such a way that the three seal rings are clamped in the axial direction.

Claims

1. A mounting for a guide wheel which is arranged behind a ships propeller and which rotates about the axis of the propeller, characterised in that for mounting the guide wheel a bell shaft (12) with a self-aligning roller bearing (14) and a roller bearing (15) is provided in the hub (13) of the guide wheel in place of the cup (spinner) which covers the moving apparatus (8) for an adjustable propeller (10) and is protected against seawater by means of a seal (16) and a cover (17).

2. A mounting in accordance with claim 1, characterised in that the self-aligning roller bearing (14) is arranged in the hub (13) of the guide wheel behind the roller bearing (1 5) and is hydraulically secured.

3. A propeller arrangement for a ship comprising a first propeller, in particular an adjustable propeller, having a hub; a shaft drivingly connected to and extending forwardly from said hub for rotating said first propeller, a bell shaft or hollow stub shaft secured to said hub and extending rearwardly from said first propeller for supporting a bladed guide wheel or guide propeller, said bladed guide wheel or guide propeller being substantially freely rotatably mounted on said bell shaft via first and second bearings comprising a first roller bearing and a second selfaligning roller bearing.

4. A propeller arrangement in accordance with claim 3 wherein said self-aligning roller bearing is disposed behind said first roller bearing relative to the normal direction of travel of an associated ship.

5. A propeller arrangement in accordance with either of claims 3 and 4 wherein said self-aligning roller bearing includes a hydraulically clampable sleeve, as known per se, for controlling the radial fit thereof.

6. A propeller arrangement in accordance with any one of the preceding claims 3 to 5 wherein said bladed guide wheel or guide propeller has a hub for receiving said bearings and wherein a seal is provided between said guide wheel hub and said bell shaft, or said hub of said first propeller, permitting relative rotation therebetween but preventing water reaching said bearings.

7. A propeller arrangement in accordance with claim 6, wherein said seal comprises at least two relatively rotatable seal rings and wherein one of said seal rings is secured to said hub of said bladed guide wheel and preferably serves to secure an outer race of said roller bearing against a shoulder or spacer provided in said hub of said bladed guide wheel.

8. A propeller arrangement in accordance with either of claims 6 or 7, wherein a cover is secured to the end of said hollow bell shaft and preferably assists in securing the inner race of said self-aligning roller bearing.

9. A propeller arrangement in accordance with any of the preceding claims 3 to 8, wherein a second cover is connected to the rear end face of said hub for said bladed guide wheel and preferably secures the outer race of said self-aligning bearing against a shoulder or spacer provided in said hub for said bladed guide wheel.

1 0. A propeller arrangement in accordance with any one of the preceding claims 3 to 9, wherein a spacer is provided between the inner races of said roller bearing and said self-aligning roller bearing, and wherein the inner race of said roller bearing is clamped via said spacer against a shoulder or spacer at the axially forward end of said bell shaft.

11. A propeller arrangement substantially as herein described with reference to and as shown in the accompanying drawings.