JPS6158356B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water jet propulsion device used in a small boat, and particularly to the structure of its suction port.

In general, a waterjet propulsion system sucks water such as seawater through a suction port opened on the bottom of the ship, accelerates this water with an impeller installed in a duct, and jets it strongly backwards.The reaction force is used to generate propulsive force. It is known that it is possible to obtain Usually, a grid is attached to the suction port for the purpose of preventing bulky waste from flowing into the duct. Since this lattice is installed so as not to protrude from the bottom surface of the ship, the rear end edge of the opening edge of the suction port may protrude below the rear end of the lattice. If the rear edge of the suction port protrudes below the lattice in this way, if it runs onto shallow water or driftwood, this rear edge will be damaged, which will not only make it unstable to hold the lattice, but also cause it to leak into the duct. causing disturbances in the flow of water,
There are also problems such as the paint on the suction port peeling off and causing corrosion.

This invention was made based on the above circumstances, and it is an object of the present invention to provide a suction port structure for a waterjet propulsion device that can prevent damage to the rear edge of the suction port without requiring any particularly troublesome means. . That is, in order to achieve the above object, the present invention provides a lattice formed by a plurality of lattice bars arranged in parallel in the front-rear direction at a suction port that opens underwater, and connects the rear ends of these lattice bars to the rear end of the suction port. The present invention is based on a water jet propulsion device fixed to the opening, and is characterized in that the lattice is provided with a guard portion that extends below the lattice bars and extends along the rear edge of the opening inside the suction port. .

An embodiment of the present invention will be described below based on the drawings.

In the figure, numeral 1 indicates the hull, which is made of, for example, FRP (fiber-reinforced plastic). A recess 4 is formed in the hull 1 from the rear of the bottom surface 2 to the transom 3, and a suction duct member 5 made of aluminum alloy or the like is attached to the recess 4. This suction duct member 5 constitutes a suction duct 6, and constitutes a suction port 7 between it and the hull 1 on the bottom surface 2 of the ship. That is, as shown in FIG. 2, the front part of the suction port 7 is formed by the hull 1, and the rear part of the suction port 7 is formed by the suction duct member 5, which is approximately U-shaped. A grating 8 is attached to this suction port 7 for capturing bulky waste, which will be described later. A bearing chamber 9 is formed in the recess 4 of the hull 1 and is recessed toward the inside of the ship. This bearing chamber 9 includes a bearing case 10 formed integrally with the suction duct member 5.
are fitted in a liquid-tight manner via a seal member 11. A bearing 12 and an oil seal 13 are mounted inside the bearing case 10, and support the drive shaft 14 rotatably and in a fluid-tight manner. This drive shaft 14 has one end introduced into the ship and connected to an engine (not shown), and the other end, that is, the rear end, introduced into an impeller duct to be described later. An impeller duct member 15 made of aluminum alloy or the like is integrally connected to the rear end of the suction duct member 5.
Inside this impeller duct member 15 is a suction duct 6.
An impeller duct 16 is formed which communicates with the. The impeller duct member 15 has a fixing flange 17 at the front end, and is fixed to the transom 3 by connecting the fixing flange 17 with bolts 18 and nuts 19. Therefore, the suction duct member 5 is supported by the hull 1 via the impeller duct member 15. Stator vanes 20 are integrally provided within the impeller duct member 15 at intervals in the circumferential direction, and a bearing case 21 is integrally provided in the center of these stator vanes 20. A bearing and an oil seal (not shown) are installed in the bearing case 21, and rotatably support the rear end of the drive shaft 14. An impeller 22 is attached to the drive shaft 14 so as to be located in front of the stationary blades 20 and rotate together with the impeller 22.

Further, a steering nozzle 24 is connected to the rear end of the impeller duct member 15 via support shafts 23a and 23b attached up and down so as to be swingable in left and right horizontal directions. This steering nozzle 24 can be turned in the left-right direction by an operating means (not shown) from inside the ship, and thereby the traveling direction of the ship body 1 can be controlled. Further, on the side surface of the steering nozzle 24, reverse injection nozzles 25, 25 (only one of which is shown) directed diagonally forward of the hull 1 are provided. A forward/reverse switching lid 26 is attached to the steering nozzle 24 so as to be rotatable around a support shaft 27, and the forward/reverse switching lid 26 is operated by an operation means (not shown) inside the ship. Thus, the rear end opening of the steering nozzle 24 can be opened and closed. When the steering nozzle 24 is closed, the forward/reverse switching lid body 26 changes the direction of the water jetted rearward through the steering nozzle 24 toward the front, and switches the reverse injection nozzles 25, 25 on. It is designed to flow forward through the air. As a result, the hull 1 can move backward.

The grid 8 attached to the suction port 7 is also shown in FIGS. 2 and below. That is, the lattice 8 is made up of a plurality of lattice rods 28 arranged along the front-rear direction and spaced apart from each other in the left-right direction.
Surrounding rods 30 having guard portions 29 are located at both left and right ends. The surrounding rod 30 is bent into a roughly U-shape having the same shape as the rear end edge of the suction port 7, and the U-shaped bent portion forms a guard portion 29, and straight portions at both ends of the guard portion 29. are located on both the left and right sides of the lattice bars 28 and serve as the lattice bars 30a and 30b. The guard part 29 is located below each lattice bar 28, and the guard part 29 is located below each lattice bar 28, and the lattice bar 2
8... is welded. Therefore, these lattice bars 28 are connected together by the surrounding bars 30 to form the lattice 8. However, each of the above lattice bars 2
The rear ends of the suction duct members 8 are inserted into insertion holes 31 formed at the rear edge of the suction port 7 in the suction duct member 5. Therefore, in the suction duct member 5, a projecting edge 32 located lower than the insertion holes 31 is formed on the rear end edge of the suction port 7, and this projecting edge 32 is formed on the lower surface of each lattice rod 28... It is facing downwards. However, a guard portion 29 of the enclosing rod 30 is projected from the lower surface of each lattice rod 28, and this guard portion 29 is attached to the above-mentioned projecting edge when each lattice rod 28 is completely inserted into the insertion hole 31. 32 in front of the suction port 7 and along the protruding edge 32.
It will be located in the shape of a letter. In addition, each lattice bar 28...
front end of the front end and the lattice bars 30a, 30b of the surrounding bar 30
The front end is inserted into a penetration hole 34 formed in the support plate 33. This support plate 33 is fixed to the recess 4 of the hull 1 forming the front part of the suction port 7 via screws 35 . Note that the support plate 33 is formed with an upright stopper wall 36, and the lattice rods 28
...30a, 30b are prevented from moving. Therefore, the rear end of the grid 8 is supported by the suction duct member 5, and the front end is attached to the hull 1 via the support plate 33.

In the waterjet propulsion device having such a configuration, when the drive shaft 14 is rotated by the engine, the impeller 22 rotates together. This impeller 22 sucks water from the suction port 7 opened on the bottom surface 2 of the ship, accelerates it within the impeller duct 16, and pumps it rearward. This water is rectified by the stationary blades 20, then sent to the steering nozzle 24, and is ejected from the rear end opening of the steering nozzle 24. Therefore, since the reaction force of the jet flow is applied to the hull 1, this reaction force becomes a propulsive force and the ship moves forward. Note that by changing the direction of the steering nozzle 24, the traveling direction of the hull 1 can be changed, and by adjusting the rear end opening area of the steering nozzle 24 using the forward/reverse switching cover 26. Changes in forward speed, neutralization, and reversing are possible. However, in such a water jet propulsion device, since a grid 8 is attached to the suction port 7, bulky debris such as seaweed and other floating objects that try to flow into the suction duct 6 from the suction port 7 are blocked by this grating. It no longer gets caught on the grid 8 and flows into the suction duct 6, and therefore the drive shaft 1
4, impeller 22, stationary blade 20, etc., there is no problem.

By the way, if you run aground on shallow water or driftwood,
The protruding edge 32, which is the rear edge of the suction port 7 in the suction duct member 5, may collide with the shallow water or driftwood. The projecting edge 32 is protected by the guard portion 29 disposed along the
There is no direct contact with shallow water or driftwood. Therefore, damage to the protrusion 32 is prevented. Therefore, the grid 8 can be held securely, the flow of water into the duct will not be disturbed, and the suction duct member 5 does not need to be replaced, resulting in low cost. Also, corrosion caused by peeling of the paint will no longer occur.

Moreover, the guard portion 29 is integrally constructed with the lattice rods 28, and can be mounted without changing the conventional lattice mounting structure or without adopting a special guard portion mounting structure. Part 2
9 does not require any special effort such as attaching and detaching.

Further, in the lattice 8 of this embodiment, the lattice bars 28 are arranged in parallel with each other by the U-shaped guard portion 29 of the surrounding bar 30, which is formed by bending one bar into a U-shape.
...Since they are welded and connected to each other, there is no need for other connecting members for arranging the lattice rods 28 in parallel, and the number of parts is reduced. Moreover, this surrounding rod 30 is
Both ends of the letter-shaped guard portion 29 are extended to form a lattice rod 30.
a, 30b, the number of lattice bars 28... can be reduced, and if the number is not to be reduced, the spacing between the lattice bars 28..., 30a, 30b can be reduced, making it possible to increase garbage capture efficiency. It has advantages such as:

According to the present invention described in detail above, due to the presence of the guide portion, shallow water, driftwood, etc. do not directly collide with the rear edge of the suction port, and damage to the rear edge of the suction port can be prevented. can. Therefore, the holding function of the grid will not deteriorate, the flow of water into the duct will not be disturbed, and corrosion due to peeling of the paint will not occur.

Moreover, since the guard part is integrated with the grid,
There is no need for a special structure for attaching the guard portion, and therefore there are advantages such as not only requiring no effort in handling, but also eliminating the need to particularly change the structure near the suction port.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a sectional view of the rear bottom of the hull, Fig. 2 is a view along the arrow line in Fig. 1, Fig. 3 is a bottom view of the grid, and Fig. 4 The figure is a side view of the lattice. 1...Hull, 2...Bottom surface, 3...Transom, 5...Suction duct member, 6...Suction duct,
7... Suction port, 8... Grid, 14... Drive shaft, 1
5... Impeller duct member, 16... Impeller duct, 20... Stationary blade, 22... Impeller, 28...
... Lattice bar, 29... Guard section, 30... Surrounding rod,
31...insertion hole, 32...projection, 33...support plate.

Claims (1)

[Scope of Claims] 1. A waterjet propulsion device that sucks water from a suction port opened into the water, accelerates this water with an impeller in a duct, and jets it backward in the traveling direction, wherein the suction port has a plurality of water jets along the front and rear directions. A lattice consisting of lattice bars arranged in parallel is provided, and the rear ends of these lattice bars are fixed to the rear end opening edge of the suction port. A suction port structure for a water jet propulsion device, characterized in that a guard portion is provided inside the rear end opening edge along the rear end opening edge.