FI111153B - Ship propulsion device - has outer circumference of turning shaft at level where shaft intersects outline of hull of ship around shaft is intersected by propeller plane of rotation - Google Patents

Abstract

The ship propulsion device includes a turning shaft (4) having an upper portion journalled in the hull (1) of the ship for turning the turning shaft about an axis (7) and at least one lower portion and an underwater propeller pod (3) attached to the lower portion (s) of the turning shaft (4) and screw propulsion device (2) journalled for rotation in the underwater propeller pod (3) and having a propeller plane (6) of rotation and a propeller axis of rotation. Each lower portion of the turning shaft (4) is offset from the upper portion of the turning shaft so as not to be aligned with it along the turning axis (7) thereby enabling the propeller plane (6) of rotation, measured along the propeller axis of rotation, to be at, or close to, the turning axis (7).

Description

111153

PROPULSION DEVICE - PROPULSIONSANORDNING

The invention relates to a ship propulsion device according to the preamble of claim 1.

Traditionally ships have one or more propulsion propellers and rudders. By contrast, there has recently been a shift towards the so-called "propulsion system" for ships' main propulsion. rudder propeller devices. Such are described, for example, in Fl 63549, Fl 65957, Fl 75128, Fl 75775, Fl 76977 and Fl 96590. The propeller gondola is mounted on a shaft structure that is pivotally mounted on the ship's hull. This shaft structure is hereinafter referred to as the pivot arm. By means of the pivoting movement of the pivot arm, the propeller gondola and thus the propulsion propeller current generated by it can be directed in the desired direction. Therefore, the rudder propeller device can also act as a steering control for the ship. The ship may have one or more rudder propeller devices. Each device may have one or more propellers.

The joint pivot axis of the pivot arm and the propeller gondola need not be completely vertical, but may also be slightly oblique, such as that described in Fl 96590.

The rudder-propelled ship has excellent maneuverability, but the torque required to turn the propeller gondola is high and increases with propulsion power. High torque causes problems especially in slow-moving ships, such as tugboats and icebreakers, which use high propulsion power. Problems can occur even with propulsion power of a few hundred kilowatts.

The invention is based on the finding that the torque required to rotate the propeller gondola is also dependent on the distance of the rotary plane of the propeller from the common pivot axis of the propeller and propeller. Traditionally, rudder propeller devices have been constructed such that the central portion of the propeller gondola is located near said pivot axis. In this case, the propeller 2 111153 at the end of the propeller gondola is quite far from the pivot axis, which results in a large torque required to rotate the propeller gondola. This causes problems with high propeller propulsion units. Propeller propulsion units of more than 20 MW are already planned. Especially in this power range, the torque required to turn a propeller-mounted conventionally mounted propeller is extremely high and requires very strong steering, which is disadvantageous.

It is an object of the invention to reduce said problem so that the high-powered rudder propeller can also be rotated with a reasonable amount of torque. The object of the invention is achieved in the manner mentioned in claim 1. Since the rotation plane of the propeller or propellers according to the invention is close to the pivot axis of the pivot arm and the propeller, it follows that the torque required for steering, even at high propulsion power, remains relatively low.

In the solution of the invention, the number of propellers mounted on one propeller gondola is preferably one or two. The term "propulsion medium" refers to propellers of a propellant, regardless of their number. If there are two propellers, it is preferable that they are mounted axially close together and connected to the operating system so that they rotate in opposite directions. The propulsion power of the propellers is thus improved in a known manner. The improvement can be about 10 ... 20%. For simplicity, the invention will first be described as a single propeller version.

The solution according to the invention requires that the pivot arm be redesigned. It can no longer be a straight pipe, but at least in part must be curved or staggered. In most cases, this means that the rotation plane of the propeller cuts the pivot arm above the propeller. If the pivot arm and propeller axis of rotation are at right angles to each other, said cut is generally a sign that the propeller is sufficiently short from the pivot axis of the pivot arm and propeller. Then the torque of the propeller gondola will remain relatively low and the advantages of the invention will be realized. This is particularly true when said shearing occurs at or below the point where the propulsive force of the propeller on the pivot arm is greatest.

3, 111153

The propulsion propeller may be thrusting or thrusting as described in Fl 96590. The advantages of the invention are generally more apparent with the propeller being driven, since the torque required to turn the propeller gondola is in some cases greater with the propeller than with the propelling propeller.

According to the invention, it is intended that the propulsion propeller is on one side of the pivot axis of the propeller gondola and that the propeller probe or at least almost the entire propeller probe is on the other side of the pivot axis. The term "nearly all propeller gondola" means at least about 80%, preferably at least about 90% of the length of the gondola, not including the propeller portion. If the propeller drive motor is in the propeller gondola, "almost the entire propeller gondola" means that the engine power generating components, e.g., the electric motor stator and rotor, except for the rotor bearings, are on one side of the pivot axis relative to the propeller. This also achieves a fairly advantageously balanced solution in terms of mass forces.

The propulsion engine may be mounted on a propeller gondola e.g. as described in Fl 96590. In this case, it must be taken into account that the propulsion power obtained from the motor depends on the size of the motor. The large diameter of the engine is, for hydrodynamic reasons, detrimental to the propulsion power of the propeller. The size of the engine can also be increased in its longitudinal direction, but then the dimensions of a conventional helm propeller device become unfavorable. According to the invention, the engine can be constructed so that it is on both sides of the propeller. Without unduly increasing the dimension of the propeller gondola from its pivot axis, a motor with a given power at a given power is smaller than if the motor were only on one side of the propeller. The embodiment described is even more advantageous in the two-propeller version, in which the propulsion drive motors can be positioned symmetrically with respect to the propeller-gondola pivot axis. In this version, the propeller gondola can also be divided into two separate parts, each with one propeller. The portions of the propeller probe then extend away from the common pivot axis of your propeller probe portions relative to its propeller.

If the propeller gondola extends to either side of the propulsion means, it is hydrodynamically advantageous if the propeller gondola and propellers are a solid, streamlined body. This is accomplished by increasing the radial direction of the hub portion of the propeller or propellers so that it is completely or nearly equal in diameter to the propeller gondola.

If the propulsion device is Pulled, it is important that its propeller blades do not rotate too close to the pivot arm. In particular, a minimum distance of 10%, preferably at least 15% of the propeller diameter from the outer arms of the blades is recommended.

In the higher power range of the scope of the invention, that is, at least about 1 MW per propeller device, an electric motor in a propeller gondola has proven to be the most advantageous drive motor solution. Such solutions are described in Fl 76977 and Fl 96590. Other known alternatives are hydraulic drive or a rather widely used mechanical transmission. In the case of mechanical transmission from the propulsion engine onboard the propeller, it is preferable to construct the pivot arm so as to provide at least one rectangular through-passage space in which the transmission shaft connected to the propeller through the angular gear can be located. The arrangement of the transmission is simple if the passage state includes the pivot axis of the pivoting arm.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a side view of a single propeller version of the invention, Figure 2 schematically shows a side view of another single propeller version of the invention, Figure 3 schematically shows a side view of Figure 2 of the invention. shows, in a side view, a second twin-propeller version corresponding to Figure 2 of the invention.

In the drawings, 1 means the hull of the ship, 2 its propulsion means, i.e. in Figures 1 and 2 the propulsion propeller, 3 the propeller gondola bearing the propulsion device and 4 the propeller gondola pivot arm. The upper end of the pivoting arm 4 is mounted on a pivoting bearing 5 only schematically shown in the hull 1 and the lower end of the pivoting arm 4 is attached to the propeller probe 3. The upper end of the pivoting arm 4 is moved substantially closer to the pivot arm 4. In accordance with the invention, the distance a between the propeller plane 6 and the pivot arm pivot axis 7 is minimized. If the axis of rotation of the propeller 2 is not at right angles to the axis of rotation 7, the distance a is measured at the axis of rotation of the propeller 2. The distance a is preferably not more than about 20% of the diameter of the swivel bearing 5. It is also contemplated that the distance a is at most 0.3 D, preferably at most 0.25 D, and most preferably at most 0.2D.

The propellers are shown only schematically in the drawings. For example, the number of propeller blades is not shown in the drawings.

Figure 1 illustrates a mechanical transmission to the propeller 2. This transmission includes a drive gear 8, a vertical transmission shaft 9, and a conical gear 10 through which the propulsion force is transmitted to the propeller 2. 9 is possible on the swivel arm.

The bending stress exerted by the propeller's propulsion force on the pivot arm depends on the pivot arm's cross-sectional area and the checkpoint distance from the propeller shaft. In the event that the rotation plane 6 of the propeller 2 is substantially parallel to the pivot axis 7, the rotation plane 6 should intersect the pivot arm 4 at or below said bending stress. Generally, the bending stress is highest at the plane where the pivot arm 4 meets the ship's hull 1. In the embodiment of Figure 1, the rotation plane 6 of the propeller 2 intersects the pivot arm 4 well below that plane. Thus, almost the entire propeller gondola 3 is on the opposite side of the pivot axis 7 with respect to the propeller 2.

Instead of a mechanical transmission, a drive motor, e.g. an electric motor, located in the propeller probe 3 can be used. This is a popular embodiment of the invention because it avoids multi-gear transmission. According to the invention, the power generating parts of the electric motor, i.e. the motor rotor and the stator, are preferably located on the other side of the pivot axis 7 than the propeller 2. The electric motors are only schematically shown in Figure 2.

6111153

In the embodiment of Figure 1, a propeller is recommended. In this case, the minimum distance b between the propeller blades and the swing arm 4 must not be too small, otherwise the swing arm will adversely affect the propeller flow. According to Figure 1, the distance b is about 15% of the diameter D of the propeller 2.

In the embodiment of Figure 2, the propeller gondola is divided into two sections 3a and 3b, of which section 3a is normally forward facing. Propeller 2 is powered by two electric motors 11a and 11b. This arrangement provides the advantage that the relatively small diameter of the drive motor results in high power due to the fact that the axial length of the motor can be increased compared to e.g. what would be practically possible in the embodiment according to Fig. 1.

In the embodiment of Figure 2, the rotation plane 6 of the propeller 2 and the axis of rotation 7 of the propeller gondola 3a, 3b coincide. In this embodiment, the distance b between the propeller 2 and the nearest part of the pivoting arm 4 is considerably longer than in the embodiment of Figure 1.

In the embodiment of Fig. 3, the structure is essentially the same as in Fig. 2, but here two propulsion propellers 2a and 2b are rotated in opposite directions to each other. In this way, higher propulsion power is obtained with the same operating power. At best, the improvement can be close to 20%.

In the embodiment of Figure 4, the solution of Figure 3 has been further developed. The hubs of the propellers are enlarged so that a single cigar-shaped part of the propeller probe 3 is formed. This solution generally requires that the external diameter of the propellers be slightly increased.

The invention is not limited to the embodiments shown, but many variations thereof are conceivable within the scope of the appended claims.

Claims (9)

1. A high power vessel propulsion device, which device is provided with a mechanical, electrical or equivalent drive device and comprising a pivot bearing (5) arranged on the hull (1) of the vessel, a pivot arm (4) stored at its upper end at the pivot bearing and extending from the pivot bearing and the ship's hull, as well as a propeller gondola (3) fixed at the lower end of the pivot arm (2, 2a), the pivot arm being rotatable about a substantially vertical pivot axis (7), characterized in that in the pivot arm ( 4) a rectangular passage space is formed for receiving a straight conductor gondola (3) conductive and connected to a mechanical drive device (9), or an electric motor (11a) connected to the propeller gondola (3) connected to the propeller gondola (3) , 11b) or equivalent, and that the rotation plane (6) of the propulsion means (6) at the axis of rotation of the propulsion means is arranged in the vicinity of the pivot axis (7). Propulsion device according to claim 1, characterized in that the rotation plane (6) of the propulsion means (2) intersects the pivot arm (4) within the area between the propulsion means (2) and the hull (1) of the vessel. Propulsion device according to claim 1 or 2, which has a single pulling or pushing propulsion propeller (2) installed at the end of the propeller gondola (3), characterized in that the rotation plane (6) of the propulsion means (2) and at least almost the entire propeller gondola (3) lies on different sides of the rotary shaft (7). 4. A propulsion device according to claim 3, wherein the drive motor (11a, 11b) is located in the propeller gondola (3), characterized in that the entire part of the driving motor which develops power lies on the opposite side of the rotary shaft (7) in relation to the propulsion means (2). . 10 111153 5. Propulsion device according to claim 1 or 2, characterized in that the propeller gondola (3) extends on each side of the rotation plane (6) of the propulsion means (2) so that on each side of the propulsion means there is a driving motor (11a, 11b) or other power transmission coupled to the propulsion means (2). A propulsion device according to claim 5, characterized in that the propeller gondola (3) and a propulsion means (2a, 2b) present at its center together form a uniformly thick or almost uniformly thick unit. Propulsion device according to any of claims 1, 2, 5 or 6, characterized in that in the known propeller gondola (3) two coaxial, axially adjacent propulsion means (2a, 2b) are rotated in a shaft direction. opposite directions. Propulsion device according to any of the preceding claims, characterized in that one or more propellers (2, 2a, 2b) exist as propulsion means. Propulsion device according to any one of the preceding claims, wherein the propeller (s) acting as propulsion means (2) or propellers are drawn, characterized in that the smallest distance (b) between the pivot arm (4) and the blade of the nearest propeller (2) is at least 10%, at least 15% of the propeller diameter (D).