GB2098561A

GB2098561A - Ship's propulsion means

Info

Publication number: GB2098561A
Application number: GB8213540A
Authority: GB
Original assignee: BROWN GEAR INDUSTRIES DAVID Ltd; David Brown Gear Industries Ltd
Current assignee: BROWN GEAR INDUSTRIES DAVID Ltd; David Brown Gear Industries Ltd
Priority date: 1981-05-15
Filing date: 1982-05-11
Publication date: 1982-11-24
Also published as: GB2098561B

Abstract

In ships' propulsion means, if an auxiliary mechanism is connected to the propeller shaft between the propeller and the gearbox, longitudinal space is wasted. If, however, said shaft is extended through the gearbox to enable said mechanism to be connected to its forward end to avoid said waste, it has been impracticable to mount the gearbox flexibly on the hull to reduce vibration and noise. This problem is solved by providing the gearbox with a tubular output shaft 24 surrounding with clearance a forward zone of the propeller shaft extension 13 and connecting said output shaft to the propeller shaft by means of a tubular flexible coupling assembly 29, 30, 34, 35, 36, 37 surrounding with clearance an aft zone of said extension, said assembly being surrounded with clearance by a sleeve 17 connected to the propeller shaft and carrying a thrust bearing 21. The propeller shaft, extension and sleeve are journalled in bearings rigidly mounted on the hull, but the arrangement enables the gearbox including its output shaft to be unrestrictedly flexibly mounted thereon. <IMAGE>

Description

SPECIFICATION Ship's propulsion means This invention relates to propulsion means for a ship.

If either the ship's propeller is of controllable pitch, and the propeller pitch control means is disposed between the ship's gearbox and the propeller and connected hydraulically to the propeller by way of a muff coupling surrounding the propeller shaft in known manner, or alternatively the ship were to have a secondary engine such as an electric motor disposed between the gearbox and the propeller, valuable longitudinaH space 7s wasted although there is nothing to prevent the gearbox from being flexibly mounted on the ship's hull to reduce vibration and resulting noise.If, on the other hand, the propeller shaft is extended through the gearbox, and the propeller pitch control means or the secondary engine is disposed at the forward end of the extension in order to avoid said waste of space, it then becomes difficult to mount the gearbox flexibly on the hull. In a prior attempt to solve the difficulty with propeller pitch control means disposed at the forward end of the extension, the gearbox is flexibly mounted on the hull when lower output torques and/or axial propeller thrusts are exerted but is moved automatically into rigid contact with stops on the hull when higher output torques and/or axial propeller thrusts are exerted.

The object of the present invention is to provide ship's propulsion means with a forward extension of the propeller shaft whilst enabling the gearbox to be flexibly mounted on the hull at all times regardless of operating conditions.

According to the invention, ship's propulsion means comprise a propeller shaft; a forward extension of said shaft; a gearbox having a tubular output shaft surrounding a forward zone of the extension; a tubular flexible coupling assembly surrounding an aft zone of the extension and driveably connecting the output shaft to the propeller shaft; and a flanged sleeve which is rigidly secured at its aft end to the propeller shaft, surrounds the coupling assembly, and has its flange disposed in a thrust bearing.

A preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing which is a radial section through a portion of a ship's propulsion means.

Referring now to the drawing, a ship's propulsion means includes a tubular propeller shaft 10 journalled in bearings (not shown) which are rigidly mounted on the ship's hull. Said shaft carried a controllable pitch propeller (not shown) at its aft, outboard end, and has a radially outwardly projecting flange 1 2 at its forward, inboard end. A tubular forward extension 13 is rigidly secured to the forward end of the propeller shaft 10 by means of a radially outwardly projecting flange 14 at the aft end of the extension 13, which flange is of substantially smaller diameter than the flange 12 on the propeller shaft 10 and fits within a shallow counterbore 1 5 formed in the forward end of said shaft.The forward end of the extension 13 is journalled in a bearing 1 6 which is rigidly mounted on the ship's hull, and the length of the extension 13 is, say, seven or eight times its diameter to give it reasable flexibility for accommodation of flexure of the hull. A sleeve 1 7 is rigidly secured by means of a radially outwardly projecting flange 1 8 at its aft end to the flange 12 on the propeller shaft 10, and surrounds an aft zone of the extension 1 3 with substantial radial clearance referred to hereinafter.

The sleeve 17 is journalled at its forward end in a bearing 19 which is rigidly mounted on the ship's hull, and has another radially outwardly projecting flange 20 between its ends. Said other flange 20 is disposed in a thrust bearing of the well known type comprising two sets of tiltable pads 21 supported in an annular chamber 22 in which there is continuously maintained a spray or an upward circulation of oil, each set of pads cooperating with one of the faces of said other flange 20. Oil seals 23 are provided between the sleeve 1 7 and a housing 9 containing the chamber 22, and the housing 9 is rigidly mounted on the ship's hull.

A tubular output shaft 24 of the ship's gearbox surrounds a forward zone of the extension 13, and has a gear wheel 26 formed integrally on it at the mid-point of its length. The output shaft 24 is journalled in bearings 27 and 28 which are disposed one on each side of the gear wheel 26 thereon and mounted in the gearbox, the bearing 28 acts also as a thrust bearing to prevent axial movement of the output shaft 24, and the gearbox is flexibily mounted on the ship's hull.The output shaft 24 is driveably connected to the propeller shaft 10 by a tubular coupling assembly including a tubular member 29 passing through the aforesaid clearance between the extension 1 3 and the sleeve 1 7 and having a radially outwardly projecting flange 30 at its aft end, said flange being of substantially smaller diameter than the flange 1 8 at the aft end of the sleeve 1 7 and being disposed in a counter-bore 31 formed in the aft end of the sleeve 17. The flange 30 on the tubular member 29 is driveably connected to the end face 32 of the counterbore 31 by means of a diaphragm coupling 33. At the forward end of the tubular member 29 there are formed splines 34 on which a collar 35 having a radially outwardly projecting flange 36 is rigidly secured by a nut 37.

Said flange 36 is drivably connected by means of a diaphragm coupling 38 to a radially outwardly projecting flange 39 of similar size formed at the aft end of the output shaft 24. A conventional propeller pitch control means (not shown) is disposed at the forward end of the extension 1 3 and operatively connected to the propeller by way of the extension 1 3 and the propeller shaft.

The bearings 1 6 and 1 9 respectively supporting the extension 13 and the sleeve 17, together with the thrust bearing 9, 21, 22, are conveniently all rigidly mounted in an outer casing 11 which is itself rigidly mounted on the ship's hull, and the gearbox comprises an inner casing 25 supported by flexible mounts (not shown) in the outer casing 11.

In operation, the end thrust on the propeller shaft 10, which varies in accordance with both the power being transmitted and the pitch of the propeller, is absorbed by the thrust bearing 9, 21, 22. Variations in alignment of the output shaft 24 and the propeller shaft 1 0, due to flexure of the ship's hull and to the flexible mounting of the gearbox on the hull, are accommodated by the tubular flexible coupling assembly 29, 30, 34, 35, 36, 37 and the diaphragm couplings 33 and 38 interconnecting said shafts.

Thus the propeller pitch control means are so disposed that no longitudinal space is wasted, and at the same time the transmission of vibrations from the gearbox to the ship's hull is reduced.

In a modification, the extension is formed integrally with the propeller shaft. In another modification, the tubular flexible coupling assembly driveably connects the output shaft directly to the propeller shaft instead of indirectly by way of the aft end of the sleeve. In a further modification, one or each of the diaphragm couplings is replaced by a different type of flexible coupling. In yet another modification, the bearing at the forward end of the sleeve is omitted, whereby a further saving in longitudinal space is achieved. In yet a further modification, the bearing at the forward end of the extension is omitted. In a final modification, the propeller pitch control means is removed from the forward end of the extension and a secondary engine such as a reversible electric motor is driveably connected to said end, and the controllable pitch propeller may be replaced by a fixed pitch propeller.

Claims

1. Ship's propulsion means comprising a propeller shaft a forward extension of said shaft; a gearbox having a tubular output shaft surrounding a forward zone of the extension; a tubular flexible coupling assembly surrounding an aft zone of the extension and driveably connecting the output shaft to the propeller shaft; and a flanged sleeve which is rigidly secured at its aft end to the propeller shaft, surrounds the coupling assembly, and has its flange disposed in a thrust bearing.

2. Ship's propulsion means according to claim 1, wherein the extension is rigidly secured to the propeller shaft.

3. Ship's propulsion means according to claim 1 , wherein the extension is integral with the propeller shaft.

4. Ship's propulsion means according to any one of the preceding claims, wherein the coupling assembly driveably connects the output shaft indirectly to the propeller shaft, being connected directly to the aft end of the sleeve.

5. Ship's propulsion means according to any one of claims 1 to 3, wherein the coupling assembly driveably connects the output shaft directly to the propeller shaft.

6. Ship's propulsion means according to any one of the preceding claims, wherein the coupling assembly comprises a tubular member having a diaphragm coupling at each of its ends.

7. Ship's propulsion means according to any one of the preceding claims, wherein the gearbox is flexibly mounted on the ship's hull, and the propeller shaft, the extension and the sleeve are journalled in bearings which, together with the thrust bearing, are rigidly mounted on the ship's hull.

8. Ship's propulsion means according to any one of claims 1 to 6, wherein the gearbox is flexibly mounted on the ship's hull, and the propeller shaft and the extension are journalled in bearings which, together with the thrust bearing, are rigidly mounted on the ship's hull.

9. Ship's propulsion means according to any one of claims 1 to 6, wherein the gearbox is flexibly mounted on the ship's hull, and the propeller shaft and the sleeve are journalled in bearings which, together with the thrust bearing, are rigidly mounted on the ship's hull.

10. Ship's propulsion means according to any one of, claims 1 to 6, wherein the gearbox is flexibly mounted on the ship's hull, and the propeller shaft is journalled in bearings which, together with the thrust bearing, are rigidly mounted on the ship's hull.

11. Ship's propulsion means according to any one of claims 7 to 9, wherein the bearing or bearings supporting the extension and/or the sleeve, together with the thrust bearing, are rigidly mounted in an outer casing which is itself rigidly mounted on the ship's hull, and the gearbox comprises an inner casing flexibly mounted in the outer casing.

12. Ship's propulsion means according to any one of the preceding claims, wherein the propeller shaft carried a controllable pitch propeller, and a propeller pitch control means is disposed at the forward end of the extension and operatively connected to the propeller by way of the extension and the propeller shaft.

13. Ship's propulsion means according to any one of claims 1 to 11, wherein a secondary engine is driveably connected to the forward end of the extension.

14. Ship's propulsion means according to claim 13, wherein the secondary engine is a reversible electric motor.

1 5. Ship's propulsion means constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawing.