JPH0218277B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a propulsion device for a ship.

When the propeller rotates in the wake after the ship, the wake distribution (1-w) in the plane of the propeller changes in the circumferential direction. That is, as shown in FIG. 1a, when the propeller blade passes through a point at 0° (top) in the circumferential direction, it becomes smaller, and when it passes around 180° (bottom) in the circumferential direction, it becomes larger. Note that FIG. 1b shows the rotation angle position of the propeller blades. Therefore, when the propeller blade passes around 0°, the wake becomes non-uniform, and the pressure difference between the pressure surface and the back surface of the propeller blade fluctuates drastically, causing hull vibration and cavitation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a propulsion device for a ship that can alleviate the pressure difference between the pressure surface and the back surface of a propeller blade due to a change in wake.

That is, in the present invention, an annular recess is formed on the outer periphery of the bow side of the propeller boss portion corresponding to the non-rotating portion of the stern around the propeller shaft, and one end of each propeller blade is opened to the propeller blade pressure surface, and the other end is opened to the propeller blade pressure surface. A first communication passage that opens into the annular recess, and a second communication passage that has one end opening at the back surface of the propeller blade and the other end opening into the annular recess, and the second communication passage is located in the annular recess. A control ring having a communication recess that allows the openings at the other ends of the first communication passage and the second communication passage to communicate with each other within a predetermined range is fixed to the stern non-rotating part, and the communication recess of the control ring is controlled according to the wake distribution. The top of the ring is characterized by a nearly crescent-shaped top with a wide opening.

According to the above configuration, the pressure difference between the propeller blade pressure surface and the back surface caused by the wake can be alleviated, so it is possible to reduce the hull vibration caused by the propeller and the cavitation generated in the propeller, thereby increasing the propeller efficiency. can be improved.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. Reference numeral 1 denotes a propeller for a ship, which is a bow side portion of a propeller boss portion 2 and a propeller shaft 3.
An annular recess 4 is formed on the outer periphery. Each propeller blade 5 has a first opening having one end opening to the propeller blade pressure surface 5a and the other end opening to the annular recess 4.
A communication passage 6 and a second communication passage 7 having one end open to the propeller blade back surface 5b and the other end opening to the annular recess 4 are bored. In addition, the above-mentioned communication paths 6, 7
The opening position on the annular recess 4 side corresponds to the mounting position of each propeller blade 5. A control ring 8 having a communication recess 8a that allows the openings of the first communication path 6 and the second communication path 7 on the annular recess 4 side to communicate with each other within a predetermined range is located within the annular recess 4 and is located at the stern. A rotating part 9 is fixed to a stand tube, for example. By the way, the communication recess 8a of the control ring 8 has a small wake distribution (shown in FIG. 1a) where the wake distribution is small.
This is for communicating the pressure surface 5a and the back surface 5b of the propeller blade 5 to alleviate pressure fluctuations, and therefore, its shape is determined according to the wake distribution. For example, according to the wake distribution shown in FIG. 1a, the communicating recess 8a is located at the top (near 0°)
It is wide at the part, and gradually narrows so that the opening area of the communication part is about half at the side part (around 90°, 270°), and the opening area of the communication part is closed at the bottom part (around 180°). Ru. Therefore, it has an almost crescent shape. Note that the control ring 8 can be replaced with one having a predetermined communication recess 8a depending on the wake distribution of the hull.

As described above, according to the marine vessel propulsion device of the present invention, the first communication path that opens to the pressure surface of the propeller blade and the second communication path that opens to the back surface of the propeller blade.
The control ring is fixed to the non-rotating part of the stern and is located in the annular recess, and the control ring is connected to the control ring as the propeller blade rotates through the crescent-shaped communication recess formed in correspondence with the wake distribution. The pressure difference between the propeller blade pressure surface and the back surface caused by the wake can be alleviated centering on the propeller blade top position where the wake distribution is small and the pressure difference is large, reducing hull vibration caused by the propeller and cavitation occurring in the propeller. Therefore, the propeller efficiency can be improved. In addition, compared to conventional propeller blades that have holes penetrating through them to alleviate the pressure difference between the propeller blade pressure surface and the back surface at all rotational positions, the pressure difference is large depending on the wake distribution. It is possible to relieve pressure mainly in areas with severe fluctuations, and efficient pressure relief is possible without reducing propeller efficiency. Furthermore, compared to the conventional method that prevents cavitation by jetting water at the predicted position of cavitation on the propeller blade surface, the structure is very simple, and the pressure between the propeller blade pressure surface and the back surface is adjusted according to the wake distribution. By using the difference, the pressure difference can be effectively alleviated.

[Brief explanation of drawings]

FIG. 1a is a graph showing the relationship between propeller rotation angle and wake distribution, FIG. 1b is a diagram showing the propeller rotation angle position, and FIG. 3 is a sectional view taken along the - arrow in FIG. 2. 1... propeller, 2... propeller boss section, 3...
...propeller shaft, 4 ... annular recess, 5 ... propeller blade, 5a ... pressure surface, 5b ... back surface, 6 ... first
Communication path, 7...Second communication path, 8...Control ring,
8a...Communication recess, 9...Stern non-rotating part.

Claims (1)

[Claims] 1. An annular recess is formed on the outer periphery of the bow side of the propeller boss portion corresponding to the stern non-rotating portion around the propeller shaft, and one end of each propeller blade opens to the propeller blade pressure surface, and the other end opens to the annular recess. A first communicating passage that opens, and a second communicating passage that has one end opening at the back surface of the propeller blade and the other end opening into the annular recess, and is located in the annular recess and connects to the first communicating passage. A control ring having a communication recess that allows the openings at the other ends of the second communication passages to communicate with each other within a predetermined range is fixed to the non-rotating part of the stern, and the communication recess of the control ring is connected to the upper end of the control ring according to the wake distribution. A propulsion device for a ship characterized by a nearly crescent-shaped top with a wide opening.