Marine propulsion – Screw propeller – Propulsion unit casing
Patent
1998-07-13
2000-04-25
Morano, S. Joseph
Marine propulsion
Screw propeller
Propulsion unit casing
440 83, B63H 2032, B63H 2334
Patent
active
060537833
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a hub assembly for journalling of the impeller in a pump housing of a water jet propulsion unit adapted for the propulsion of vessels, and is more specifically aimed at providing a hub assembly designed to allow for simplified assembly and dismounting upon replacement or maintenance work.
BACKGROUND ART
A water jet propulsion unit of the type herein referred to comprises a pump wheel or impeller, mounted on a drive shaft which is inserted through the inlet port. The drive shaft end or the impeller is journalled in the pump housing by means of plain bearings or roller bearings and preferably, as in the disclosed embodiment, by an assembly of roller bearings in cooperation.
The hub assembly of the invention is not limited to the use in water jet propulsion units of a specific kind, but may as well be utilized with units that include a flexible, though torsionally stiff connection between drive shaft and impeller as in units with splined couplings or fixed connections between drive shaft and impeller.
For water jet propulsion units of larger commercial ferries and other vessels, swiftness and simplicity of maintenance is an essential economical factor. Current, known designs do not permit dismounting of bearings or replacement of sealings unless the pump is first dismantled from the transom stern. This procedure is both time consuming and complicated since the weight of the propulsion unit increases substantially with increased size and power.
DISCLOSURE OF THE INVENTION
Enabling the simple replacement of a hub assembly or a sealing without the need for dismounting neither the pump nor the pump impeller would substantially simplify the maintenance work at quay. The hub assembly of the invention also permits maintenance of bearings and sealings without the need for lifting or docking the vessel, provided that the vessel can be trimmed at the stem to raise the assembly above the water surface. If water-lubricated plain bearings are utilized in the hub assembly, the replacement could also be made by divers below water surface.
Hence, the purpose of the invention is to provide a hub assembly designed to journal an impeller or a drive shaft end in a water jet propulsion unit that permits simplified assembly and dismounting during maintenance, thereby avoiding the previously described problems.
This purpose is met with a hub assembly according to the enclosed patent claims wherein the specific characteristics of the invention are included.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in more detail below with reference made to the attached drawing which shows, in a longitudinal cross sectional view, the hub assembly mounted in the pump housing of a water jet propulsion unit.
MODE FOR CARRYING OUT THE INVENTION
In the drawing is shown details of a water jet propulsion unit wherein the reference numeral 1 indicates a drive shaft journalled for rotation in a pump housing 2. In the disclosed embodiment, the drive shaft end comprises a shaft spindle 3 having a flange, an impeller 4 being bolted to the flange of the shaft spindle. The shaft spindle is rotationally fixed to the extended end of the drive shaft by means of a coupling 5. The drive shaft end or the shaft spindle 3 is journalled in a hub assembly according to the invention generally indicated with reference numeral 6, the hub assembly 6 being non-rotationally mounted in the pump housing stator 7.
It should be noted that the expression "shaft spindle" in the present disclosure also shall be understood to be equivalent with the drive shaft end, as the invention is not restricted to the illustrated embodiment but is also applicable in such water jet propulsion units that lack the shown connection between the drive shaft and a shaft spindle, non-rotationally attached to the drive shaft end. In other, not shown embodiments the shaft spindle 3 may be integrated in the impeller, whereas the expression "shaft spindle" also should be understood to include a correspondingly designed and journa
REFERENCES:
patent: 4948384 (1990-08-01), Bland et al.
patent: 4986775 (1991-01-01), Wantz
patent: 5045002 (1991-09-01), Torneman et al.
patent: 5094639 (1992-03-01), Onoue
patent: 5554003 (1996-09-01), Hall
patent: 5827042 (1998-10-01), Ramsay
MJP Marine Jet Power AB
Morano S. Joseph
Muldoon Patrick Craig
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