GB2151329A

GB2151329A - Marine propulsion gearbox

Info

Publication number: GB2151329A
Application number: GB08431495A
Authority: GB
Inventors: Thomas Hall
Original assignee: English Electric Co Ltd
Current assignee: English Electric Co Ltd
Priority date: 1983-12-14
Filing date: 1984-12-13
Publication date: 1985-07-17
Also published as: EP0146353A1; GB8333284D0; GB8431495D0

Description

1

GB2151 329A 1

SPECIFICATION

Marine propulsion gearbox

5 This invention relates to marine propulsion gearboxes and is particularly concerned with such gearboxes having inputs from two engines, for example diesel engines, and a single output to a propeller.

10 According to the present invention, a twin-input single-output marine propulsion gearbox has two input pinions on separate input shafts which shafts extend coaxially in opposite directions from the gearbox, the input pinions 15 engaging gear wheels on a common output shaft. The gearwheels may be integrally mounted on a common hub. There may be included a respective air operated clutch coupled to each pinion shaft, each pinion shaft 20 being provided with an axial duct for the passage of actuating air to the associated clutch, the axial ducts having access connections in the opposed inner ends of the pinion shaft.

25 The gear wheels are preferably helical gears of opposite hand so as to eliminate axial thrust on the output shaft when the input pinions are driven equally.

One embodiment of a marine propulsion 30 gearbox in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing,

which shows an elevation of the input shafting and a part section part elevation of the 35 output shafting.

Referring to the drawing, input pinions 1 and 3 are integrally mounted on respective pinion shafts 5 and 7 which rotate in bearings not shown. Thrust collars 8 and 10 embrace 40 the bearings and provide axial reaction to the thrust resulting from helical gears. The pinion shafts 5 and 7 extend in opposite directions from the gearbox to respective air operated clutches 9 and 11 which are coupled to the 45 pinion shaft flanges 1 3 and 1 5. Diesel engines not shown are coupled to the driving members of the clutches 9 and 1 1 and thus are mounted on opposite sides of the gear box. Each pinion shaft 5 and 7 has an axial 50 bore 1 7 and 1 9 which extends right through the shaft and pinion and is supplied with compressed air from respective pipes 21 and 23 via access connections in the opposed inner ends of the pinion shafts. Operating air 55 is thus supplied to the clutches through the pinion shafts. Since the axial centres of the pinion shafts are accessible at the inner ends, provision of a rotating connection between the pipes 21,23 and the bores 17, 10 is a 60 simple matter.

The output shaft is a single integral shaft 25 mounted on bearings (not shown) at positions 27 and 29. The output shaft has an enlarged cylindrical portion 31 on which an 65 output gear structure 23 is mounted between a shoulder 35 and a screwed locking ring 37. The structure 33 has a hub 34 which is keyed to the shaft portion 31, and two integrally mounted radially extending gear wheel 70 flanges 39 and 41 on which ring gears 43 and 45 are mounted respectively. These gears mesh with the pinions 1 and 3. The output gears 43 and 45 are shown in section in the drawing above the output centre line 47 and 75 in elevation below that centre line.

The output shaft 25 is provided with a flange 49 for coupling to a marine propeller. It also has a substantial thrust collar 51 engaging a thrust bearing (not shown) against 80 which the propeller acts.

The two pairs of reduction gears 1/43 and 3/45 have helical profiles and thus individually tend to exert axial thrust on the output shaft 25. However, the gears are of opposite 85 hand such that the axial thrusts due to the two inputs tend to balance, and do so if the input torques are equal.

The independent and separate nature of the input shafts and pinions permits a compact 90 coaxial input engine arrangement while still providing access to the inner ends of the shafts as described above.

Claims

95 1. A twin-input single-output marine propulsion gearbox, having two input pinions on separate input shafts which shafts extend coaxially in opposite directions from the gearbox, said input pinions engaging gear wheels 100 on a common output shaft.
2. A gearbox according to Claim 1 wherein said gearwheels are integrally mounted on a common hub.
3. A gearbox according to Claim 1 or 105 Claim 2 including a respective air operated clutch coupled to each pinion shaft, and wherein each pinion shaft is provided with an axial duct for the passage of actuating air to the associated clutch, the axial ducts having 110 access connections in the opposed inner ends of the pinion shaft.
4. A marine gearbox according to any preceding claim, wherein said gear wheels are helical gears of opposite hand so as to elimi-

115 nate axial thrust on the output shaft when the input pinions are driven equally.
5. A twin-input single-output marine propulsion gearbox substantially as hereinbefore described with reference to the accompanying

120 drawing.

Printed in the United Kingdom for

Her Majesty's Stationery Office, Dd 8818935, 1985, 4-235. Published at The Patent Office, 25 Southampton Buildings,

London. WC2A 1AY, from which copies may be obtained.