JPH07237592A - Propulsive device for water jet propelled ship - Google Patents

Abstract

PURPOSE:To prevent generation of useless resistance by preventing a reverse flow of water from a fixed louver during forward running, in a water jet propelled ship provided with a fixed louver type reverse flow generating mechanism. CONSTITUTION:In a propulsive device provided with a fixed louver 6 in a bottom surface opening part of a duct 1 successively provided in line with a jet of a water jet pump 10, a resistance generation preventing plate 3 capable of closing a lower opening part of the fixed louver 6 is turnably mounted by a rotary shaft 2 and energized in a direction of closing the resistance generation preventing plate 3 by a water pressure VB of a ship bottom water flow at forward running time, so as to prevent a reverse flow of water from the fixed louver 6 at forward running time. At reverse running time, by operating a hydraulic cylinder 8 to erect a reverse flap 5, a jet water flow 12 is changed into a reverse flow 13, to automatically open, by a water pressure VA of this reverse flow, the resistance generation preventing plate 3, and the reverse flow 13 is jetted from the fixed louver 6, to obtain reversing thrust.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propulsion device for a water jet propulsion ship, and more particularly to an improvement of the propulsion device for a water jet propulsion ship which employs a fixed louver system as a backward flow generating mechanism.

[0002]

2. Description of the Related Art Generally, a water jet ship jets seawater boosted by a pump installed on the hull from a diffuser into a steering cylinder (duct) installed at the stern at a speed of 25 to 40 m / s, and the reaction force is generated. It is a driving force. Further, the backward movement of the water jet ship is performed by turning the water flow jetted into the steering cylinder in the opposite direction.

Here, the conventional fixed louver type backward flow generating mechanism will be described with reference to FIG. 7. Reference numeral 1 indicates a duct as a steering cylinder, and the duct 1 is attached to the stern part of a water jet propulsion ship. On the jet side (downstream side) of the water jet pump 10, the steering hydraulic cylinder 9
The water jet propulsion boat can be steered continuously by turning around the turning shaft 9a.

When the boat is moving forward, the water jet pump 10
The water flow ejected from the duct 1 flows toward the downstream side (from the right side to the left side in FIG. 7) in the duct 1, ejects from the opening of the downstream end of the duct 1 (the left end in FIG. 7), and advances toward the ship. Generate thrust for use. In order to reverse the water flow ejected from the water jet pump 10 into the duct 1 in the opposite direction to generate reverse thrust on the ship, the reverse flap 5 is
The base end of the duct 1 is connected to the downstream end of the duct 1 via the shaft 5a (see FIG.
The reverse flap 5 is rotatably attached to the fixed louver in order to eject the water flow in the reverse direction when the vehicle is traveling backward with the opening of the downstream end of the duct 1 closed by operating the hydraulic cylinder 8. 6 is attached to the opening at the bottom of the duct 1.

In FIG. 7, reference numerals 8a and 8b indicate pressure oil pipes of the hydraulic cylinder 8, and reference numeral 7 indicates an arm connecting the piston rod of the hydraulic cylinder 8 and the reverse flap 5, respectively. Further, as a backward flow generating mechanism in a water jet ship, a double flap type as shown in FIGS. 8 (a) to 8 (c) is also known.

That is, the double flap type backward flow generating mechanism of FIGS. 8 (a) to 8 (c) shows the two flaps 16 and 17 operated by operating the hydraulic cylinder 8 from the forward traveling state of FIG. 8 (a). After the neutral state of 8 (b), it is displaced to the backward traveling state of FIG. 8 (c) to change the fountain flow in the duct 1 to the backward flow f.
In addition, reference numerals 15, 18, and 19 in FIGS.
Reference numeral a denotes a shaft for rotatably supporting the link 18 on the duct 1. The arrows a to g indicate the direction of the fountain flow, and the size of the arrow indicates the amount of water in the fountain flow.

[0007]

By the way, the fixed louver type backward flow generating mechanism has a smaller link mechanism than that of the double flap type shown in FIGS. 8 (a) to 8 (c), and a compact and lightweight design is possible. However, when running a hydrofoil, etc. as a hull traveling method, if the water surface height of the water jet (distance from the water surface) is sufficient, there is no problem because it is in the atmosphere. When applied to a vehicle located near the water surface, there is a problem that the reverse flow of the water flow into the fixed louver portion occurs during forward traveling, resulting in unnecessary resistance. The present invention solves such problems, and prevents unnecessary resistance due to reverse flow of water flow into the fixed louver portion as much as possible to improve the running performance of the water jet propulsion ship. The purpose is to provide a device.

[0008]

In order to achieve the above object, a propulsion apparatus for a water jet propulsion ship according to claim 1 is a water jet propulsion ship propulsion apparatus, wherein the water jet pump and the water jet pump are the same. And a duct that is connected to the jet outlet of the water jet pump and injects seawater pressurized by the water jet pump as a jet water flow, and the jet water flow in the duct that is installed in the bottom opening of the duct and ejects in the opposite direction. And a fixed louver that is rotatably attached to the duct to guide the jet water flow in the duct in a direction toward the fixed louver in order to generate thrust for backward movement on the water jet propulsion ship. It is configured to close the upper opening of the fixed louver in order to generate forward thrust on the propulsion ship. Includes a berth flaps, it is characterized in that the lower opening of the fixed louvers can be closed resistance prevention plate is provided.

A water jet propulsion ship propulsion apparatus according to a second aspect of the present invention is the water jet propulsion water vessel propulsion apparatus according to the first aspect, wherein the resistance generation prevention plate has a base end portion of the fixed louver. The lower end of the fixed louver is rotatably attached to the lower surface of the upstream end so that the lower opening of the fixed louver is automatically opened and closed by the force of the water flow when the water jet propulsion ship moves forward and backward. It is characterized by being configured in.

Further, the propulsion device for a water jet propulsion ship according to a third aspect is the propulsion device for a water jet propulsion ship according to the first or second aspect, in which a claw is projectingly provided on the resistance generation preventing plate. When the reverse flap is in a position to close the upper opening of the fixed louver, the claw is pressed by the reverse flap to urge the resistance prevention plate to a position to close the lower opening of the fixed louver. It is characterized by being configured in.

[0011]

In the above-described propulsion device for a water jet propulsion ship of the present invention, when the water jet propulsion ship is traveling forward, the resistance generation prevention plate turns around the rotation axis by the force of the backward water flow flowing under the duct. It is lifted up to close the lower opening of the fixed louver and prevent the reverse flow of water into the fixed louver. In this state, the reverse flap presses the claws protruding from the resistance prevention plate, so the resistance prevention plate is securely fixed at the position where the lower opening of the fixed louver is closed, and the water flow during high speed running is reduced. To prevent play (play of resistance prevention plate).

When the reverse flap is rotated to the backward traveling state, a part or the whole of the jet water flow hits the upper surface of the resistance generation prevention plate, and the resistance generation prevention plate automatically rotates by the water flow pressure to move the fixed louver. Open the lower opening. As a result, the jet water flow is ejected in the opposite direction.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A propulsion device for a water jet propulsion ship according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view thereof, FIGS. 2 to 5 are explanatory views of its operation, and FIG. It is an expanded side sectional view of the claw. 1 to
6, the same reference numerals as those in FIG. 7 indicate almost the same members.

As shown in FIG. 2, the propulsion device of this embodiment is also mounted in the vicinity of the rear end of the water jet propulsion ship 20. The water jet pump 10 and its jet outlet operate a steering hydraulic cylinder. And a duct 1 that is connected to enable the steering of a water jet propulsion ship by turning around a swivel axis 9a, and a fixed louver 6 that redirects the water flow in the opposite direction is attached to the opening at the bottom of the duct 1. Has been. Reference numeral 20a indicates the bottom of the ship.

The reverse flap 5 capable of closing the inner surface (upper surface) side opening of the fixed louver 6 has the same structure as that shown in FIG.
The base end portion of the duct 1 is supported by a shaft 5a attached to the downstream end portion (the left end portion in FIG. 1) of the duct 1, and is attached so as to be rotatable by operating the hydraulic cylinder 8.

Further, a resistance generation prevention plate 3 capable of closing an opening (lower opening) on the lower surface side of the fixed louver 6 has a center of the duct 1 on the lower surface of the upstream end (right end in FIG. 1) of the fixed louver 6. The water jet propulsion ship 20 is mounted via a rotary shaft 2 mounted at right angles to the line so that the water jet propulsion ship 20 can be automatically rotated by the force of the water flow during forward and backward movements. Both ends of the rotary shaft 2 are held by both side plates of the duct 1 by a bearing structure. Further, a claw 4 that can come into contact with the lower surface of the tip portion of the reverse flap 5 is provided on the opposite side of the resistance generation preventing plate 3 from the mounting portion of the rotary shaft 2.

In the above structure, the reverse flap 5 is in the state shown in FIGS. 1 and 2 (the fixed louver 6 is closed) while the boat is traveling forward, and the water jet pump 10
The seawater pressurized by is injected into the duct 1 as the jet water flow 12, and is ejected from the downstream side (left end in FIGS. 1 and 2) opening of the duct 1 to act to move the water jet propulsion ship 20 forward. .

At this time, as shown in FIG. 2, the resistance generation prevention plate 3 causes the backward water flow flowing under the duct 1.
It is swung up around the rotary shaft 2 by the water pressure of 11 and is in a closed position where it closes the lower opening of the fixed louver 6. At this time, the claw 4 is pressed by the upstream end of the reverse flap 5, so that the resistance generation preventing plate 3 is fixed in a state of covering the fixed louver 6 from below and closing the lower opening thereof.

When the reverse flap 5 is rotated in the opening direction (arrow A direction) as shown in FIG.
A part or all of the reverse flap 5 and the fixed louver 6 change the flow direction to form a reverse flow 13 and strike the upper surface of the resistance generation preventing plate 3. When the flow velocity V _{A of the} reverse flow becomes greater than the flow velocity V _B of the bottom water flow 11 according to the increase in the opening degree of the reverse flap 5 and the decrease in the boat speed, the resistance generation prevention plate 3
Is smoothly opened in the opening direction (the direction of arrow B) by the water flow pressure of the reverse flow together with its own gravity, and finally, that is, when traveling in reverse, balances at an angle along the reverse flow and stands still (see FIG. 4).

In this way, the reverse flap 5 changes the jet water flow 12 in the duct 1 to the water flow toward the fixed louver 6, and at the same time, the resistance generation preventing plate 3 opens the lower opening of the fixed louver 6. Jet stream 12
Is jetted from the fixed louver 6 as a reverse flow 13 that causes the water jet propulsion ship 20 to travel backward. At this time, since the speed of the hull is in reverse (or almost stopped), there is almost no backward water flow as in forward movement, and the resistance generation prevention plate 3 is controlled by the reverse flow 13 water pressure. It only depends on the target.

Next, the hydraulic cylinder 8 is operated to enter the forward movement again, and the reverse flap 5 is turned in the direction of the arrow D to reduce the opening degree of the reverse flap 5. Due to this, a ship bottom water flow 11 is generated toward the rear (downstream direction), and a force for turning the resistance generation prevention plate 3 in the closing direction (direction of arrow C) is generated (see FIG. 5),
At the same time, since the reverse flap 5 closes, the reverse flow that tries to open the resistance generation prevention plate 3 in the opening direction disappears. Thus, due to the decrease in the opening degree of the reverse flap 5 and the increase in the boat speed, V _A <V _B, and the resistance generation prevention plate 3 smoothly returns to the closed position. At this time, even if the forward speed of the hull is insufficient and sufficient to generate the water pressure for urging the resistance generation prevention plate 3 in the closing direction, the claw 4 in the middle position has returned to the closing position and the reverse flap 5 is returned. It is pressed by the tip of the (see FIG. 6), and the resistance generation prevention plate 3 is surely returned to the closed position.
(In FIG. 6, the claw 4 of the resistance generation preventing plate 3 immediately before the closed position shown by the solid line is pressed by the reverse flap 5 and returned to the closed position shown by the dotted line. Reference symbol E is the rotational force acting on the rotary shaft 2, F indicates the pressing force applied to the resistance generation prevention plate 3.)

In this way, when the hull enters forward traveling, the lower opening of the fixed louver 6 is automatically closed by the resistance preventing plate 3 and the increase of the hull resistance due to the backflow to the fixed louver 6 can be prevented. Become. When the resistance generation prevention plate 3 is in a position to close the lower opening of the fixed louver 6, the resistance generation prevention plate 3 is pressed by the reverse flap 5 via the claw 4, so that it is securely fixed in that position.
Even if the water jet propulsion ship runs at high speed, there is no risk of rattling vibration due to water flow. The reverse flap 5 is opened and closed by an appropriate drive mechanism such as a hydraulic cylinder, a pneumatic cylinder, an electric motor, or the like as in the conventional case.

[0024]

As described in detail above, according to the propulsion device for the water jet propulsion ship of the present invention, the following effects and advantages are obtained. (1) It is possible to prevent the backflow to the fixed louver part at the time of low draft, which is a problem of the fixed louver type water jet propulsion device, which has a large merit of small size and light weight, and the fixed louver type without impeding the high speed of the hull. The advantage of can be utilized. (2) Since the hydraulic drive mechanism or link mechanism is not used to drive the resistance generation prevention plate to open or close, and the resistance generation prevention plate is not forcibly turned against the water pressure, It can be constructed relatively lightweight and thin, and the advantages of the lightweight and small size, which is a feature of the fixed louver type, are not lost. (3) Since the resistance generation prevention plate is pressed against the reverse flap via the claws while the water jet propulsion ship is traveling forward, it is securely fixed at the position that closes the lower opening of the fixed louver. There is no risk of rattling vibrations due to water flow during high-speed traveling of a jet propulsion ship.

[Brief description of drawings]

FIG. 1 is a side sectional view of a propulsion device for a water jet propulsion ship according to an embodiment of the present invention.

FIG. 2 is a side cross-sectional view during the forward traveling.

FIG. 3 is a side cross-sectional view of the same deceleration and reverse operation start.

FIG. 4 is a side sectional view of the vehicle traveling in reverse.

FIG. 5 is a side sectional view at the start of the forward movement.

FIG. 6 is a side cross-sectional view showing an operating state of a claw near the closed position of the resistance generation prevention plate.

FIG. 7 is a side sectional view of a propulsion device for a conventional fixed louver type water jet propulsion ship.

FIG. 8 (a) is a side sectional view showing a forward state of a propulsion device of a conventional two-flap water jet propulsion ship. (b) A side sectional view showing the neutral state. (c) A side cross-sectional view showing the backward traveling state.

[Explanation of symbols]

1 Duct 2 Rotating Shaft 3 Resistance Prevention Plate 4 Claw 5 Reverse Flap 5a Axis 6 Fixed Louver 7 Arm 8 Hydraulic Cylinder 9 Steering Hydraulic Cylinder 10 Water Jet Pump 11 Bottom Water Flow 12 Jet Water Flow 13 Reverse Flow 20 Water Jet Propulsion Vessel 21 Travel Medium draft level V _A Reverse water flow water pressure V _B Ship bottom water flow water pressure

Claims (3)

[Claims] 1. A propulsion device for a water jet propulsion ship, comprising: a water jet pump; and a duct connected to an outlet of the water jet pump and injecting seawater pressurized by the water jet pump as a jet water flow. And a fixed louver provided at the bottom opening of the duct for ejecting the jet water flow in the duct in the opposite direction, and rotatably attached to the duct to generate reverse thrust on the water jet propulsion ship. For guiding the jet water flow in the duct in a direction toward the fixed louver and for closing the upper opening of the fixed louver to generate forward thrust for the water jet propulsion ship. A resistance generation prevention plate that is provided with a flap and that can close the lower opening of the fixed louver is provided. Characterized in that there, propulsion device of the water jet propulsion boat. 2. The water jet propulsion ship propulsion device according to claim 1, wherein the resistance generation preventing plate is rotatably attached to a lower surface of an upstream side end portion of the fixed louver, The lower opening of the fixed louver is opened and closed by the generation prevention plate so as to be automatically performed by the force of the water flow when the water jet propulsion ship moves forward and backward. Propulsion device. 3. The propulsion device for a water jet propulsion ship according to claim 1 or 2, wherein a claw is projectingly provided on the resistance generation prevention plate, and the reverse flap closes an upper opening of the fixed louver. At one time, the claw is pressed by the reverse flap to urge the resistance generation prevention plate to a position to close the lower opening of the fixed louver, the water jet propulsion ship. Propulsion device.