JPH0328358B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a commercial ship for both ocean-going and ice-breaking navigation, having at least one screw.

Some of the well-known vessels of this type have ships up to approx.
A steam turbine is used as the propulsion device, which has a very high rotational speed compared to the screw rotational speed of 170 rpm. A reduction gear device is interposed between the turbine shaft and the screw shaft.

Because of the intervention of the reduction gearing, this type of propulsion system involves considerable power transmission losses, which has disadvantageous consequences for the economical operation of the ship. Turbine propulsion systems are also important because, on the one hand, they must be made for ice-breaking navigation and, on the other hand, it is still necessary for commercial purposes to be able to navigate the high seas for long periods of time. It is also uneconomical in that it requires a considerably large running cost due to the large fuel consumption per horsepower. The output ratio of the turbine during ice-breaking voyage and ocean voyage is approximately 3:1 to 2:1, and the limit varies depending on the operating conditions of the ship.

The object of the invention is to improve a merchant ship of the above-mentioned type in order to significantly reduce the running costs of the propulsion system, thereby making it possible to operate the ship economically.

For this purpose, according to the invention, a low-speed two-stroke diesel engine is arranged within the hull and is connected to said screw via a series of shafts so as to directly drive said screw, and within said hull. A thrust bearing that is fixed and receives a force in the axial direction of the screw is interposed in the shaft system of the row between the screw and the diesel engine, and a thrust bearing is further provided between the bearing and the diesel engine. A clutch is interposed to allow each joint of the shaft system to which the clutch connects to be displaced in the axial direction, and further, another thrust bearing is provided in the diesel engine. It is designed to receive the axial force of the crankshaft.

A low-speed two-stroke diesel engine was installed to directly rotate the screw. That is, the rotation speed of the diesel engine and the rotation speed of the screw were made the same. Since the present invention eliminates the need for a reduction gear device, the power transmission efficiency is greatly improved. The running costs of the ship are also much lower than with known turbine propulsion systems. This is because low-speed diesel engines consume less fuel per horsepower, and this has favorable cost-effective results. By installing a thrust bearing fixed inside the hull, the diesel engine is protected from the extremely large axial thrust force generated by the screw during ice-breaking navigation.
It also simplified the engine design.

It is well known to use low speed two-stroke diesel engines to directly rotate the propellers of merchant ships that are required to sail only on the open ocean. In such cases, the axial thrust force of the screw is necessarily received by a thrust bearing located within the diesel engine.

An exemplary embodiment of the invention will be described in detail below with reference to the drawing, which is a simplified schematic illustration of a propulsion system for a commercial ship.

A low speed diesel engine 12 is arranged parallel to the longitudinal axis 10 of the ship and fixed in the hull 22 in a known manner. The drawing shows only the stern section of the ship. The engine 12 is a two-stroke engine with a crosshead and direct input to a single shaft system 21. In the drawing, the screw 16 has adjustable vanes fixed to the bottom end of the drawing. The screw 16 propels the ship both during ice-breaking and ocean-going operations.

The engine 12 has a thrust bearing 17 that receives the axial thrust force of the crankshaft.
are arranged in a known manner. Separately, a thrust bearing 15 is disposed on the shaft that supports the screw 16 and is fixed within the hull 22, so that it receives a very large axial thrust force generated from the screw 16 during ice-breaking navigation. A clutch 14 is interposed in the shafting 21 between the thrust bearing 15 and the engine 12 and is designed to receive the relative axial movement of the shafting parts it connects.

Instead of the screw 16 with adjustable blades, a screw with fixed blades may be used as an alternative.

The invention is also applicable to ships propelled by two or three screws operated in parallel. In this case, a low-speed diesel engine input to each screw and its one-row shaft system are attached to each screw.

[Brief explanation of drawings]

DESCRIPTION OF THE DRAWINGS The drawing shows a simplified schematic diagram of a propulsion system for a commercial vessel for both ocean-going and ice-breaking operations, illustrating an exemplary embodiment of the invention. 12... Diesel engine, 14... Clutch, 15... Thrust bearing, 16... Screw, 21... Shaft system, 22... Hull.

Claims (1)

[Scope of Claims] 1. In a commercial ship having at least one screw for both ocean navigation and ice-breaking navigation, low speed 2.
A thrust diesel engine is disposed within the hull and is connected to the screw via a series of shafts to directly drive the screw, and is fixed within the hull and receives the axial force of the screw. A bearing is interposed in the shaft system in the row between the screw and the diesel engine, and a clutch is interposed between the bearing and the diesel engine, and a clutch is interposed between the bearing and the diesel engine. Each joint of the shaft system is adapted to allow displacement in the axial direction, and furthermore, another thrust bearing is provided in the diesel engine to receive the axial force of the crankshaft. A merchant ship that can be used for both ocean navigation and ice-breaking navigation. 2. The merchant ship according to claim 1, wherein the screw has adjustable blades and is used for both ocean navigation and ice-breaking navigation.