JP2000128084A - Waterjet propulsion outboard - Google Patents

Abstract

(57) [Summary] (Modified) [Problem] Regarding improvements to improve the dynamic pressure recovery and rectification effect of a running water flow, a ship with low energy loss that eliminates a rapid gliding state and stall during gliding. Provide an external unit. A water jet propulsion system in which water sucked from a submerged suction casing is pressurized by an impeller of a pump casing, and pressurized water is jetted from a discharge casing opened to the rear of the stern to propel the boat. In the outboard motor, the front wall of the suction casing is extended to the vicinity of the stern 3 of the hull, the suction passage is expanded to open the water inlet 9, and the front half of the discharge casing is curved. Part is opened backward in the propulsion direction. The intake attachment 12 having an opening is connected to the water inlet of the suction casing, the upper surface opening 13a has the same diameter as the water inlet of the suction casing, and the opening 13 of the intake attachment extends in the bow direction from the upper surface to the lower surface. Extend and bring the tip of the intake attachment closer to the stern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water jet propulsion type outboard motor, and more particularly to an outboard motor capable of recovering the dynamic pressure of a traveling water flow by improving the suction flow path of the propulsion device.

[0002]

2. Description of the Related Art Conventionally, a horizontal-axis mixed-flow water jet propulsion system in which water sucked from a suction casing is pressurized by an impeller provided in a horizontal pump casing, and pressurized water is ejected from a discharge casing to propel a ship. 2. Description of the Related Art A type of outboard motor is known, for example, as described in JP-A-9-309492. In addition, the impeller connected to the drive shaft is suspended,
2. Description of the Related Art A water jet propulsion type outboard motor having a spiral jet pump is well known, for example, as described in JP-A-8-253196.

[0003]

However, in the conventional water jet propulsion type outboard motor of the horizontal axis mixed flow type, the discharge casing opened rearward of the stern is near the water surface, and at the start of cruising, The boat stalls because the watercraft is humped and jet water is jetted toward the surface of the water,
There was a danger that it would not be possible to run in a short time. Further, the water jet propulsion type outboard motor having a pump casing as a volute pump has a small water intake, so that the amount of water flowing into the pump casing is small, and there is a possibility that a negative pressure will occur during the run and the vehicle will stall. Further, since the pressurized jet water is jetted to the rear of the stern while turning in the centrifugal direction, the pipe resistance of the flow channel increases, and there is a possibility that energy loss may occur in order to obtain a large propulsive force. An object of the present invention is to provide a device capable of improving the suction performance and the rectifying effect of the water flow.

[0004]

SUMMARY OF THE INVENTION The gist of the present invention is that an impeller is hung down on an upright pump casing, and water sucked from a submerged suction casing is pressurized by an impeller of the pump casing. In a water jet propulsion type outboard motor that propells a boat by injecting pressurized water from a discharge casing that opens rearward, the front wall of the suction casing extends to near the stern of the boat, and the suction flow path is expanded. As well as opening the water intake port, the discharge casing connected to the pump casing has the first half curved,
The rear half is opened rearward in the propulsion direction. Then, an intake attachment having an opening is connected to the water inlet of the suction casing, the upper surface opening is made the same diameter as the water inlet of the suction casing, and the opening of the intake attachment is formed in the bow direction from the upper surface to the lower surface. It is also possible to extend the intake attachment so that the tip of the intake attachment approaches the stern to increase the amount of water flowing into the suction casing and enhance the rectification effect. Further, the water jet propulsion type outboard motor may be supported on the stern of the boat so as to be able to move up and down so that the water inlet of the suction casing can be adjusted with respect to the bottom of the boat.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The water intake device for a water jet propulsion device according to the present invention is configured as described above. When a ship is sailing, the water flow flowing along the bottom of the ship is expanded in the stern direction. The water flows into the suction casing through the suction port, is pressurized by the impeller of the pump casing, is transferred obliquely upward, discharges the jet water from the casing, propells the ship, and sails by the reaction force. At this time, since the front wall of the suction casing is extended to the vicinity of the stern of the hull and the water intake is expanded, the running water flow does not become swirling at the stern,
It can be made to flow into the water intake in a rectified state. And
The running water flow on the bottom of the ship is guided from the expanded water intake port along the inclined water guide channel of the suction casing, so that the suction water volume increases and cavitation does not occur, and therefore, due to the rectification effect and negative pressure Vibration and noise are prevented, the dynamic pressure of the running water flow is recovered, and high propulsion is obtained. Further, the water inlet of the suction casing can be adjusted with respect to the bottom of the boat in accordance with the traveling state of the boat.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to an embodiment. First, in FIG. As shown in FIG.
In addition, an impeller 6 connected to the drive shaft 5 is suspended,
The starting end of the pump casing 4 is connected to the suction casing 7 whose lower end is submerged, and the rear end of the pump casing 3 is connected to the discharge casing 8. The discharge casing 8 has a front half curved and a rear half opened rearward in the propulsion direction. Then, the water sucked from the water inlet 9 of the suction casing 7 is pressurized by the impeller 6 of the pump casing 4, and the pressurized water is discharged from the deflector 10 behind the casing 8 to the rear of the stern 3 on the water surface, so that the boat 2 Is being promoted.

As shown in FIG. 3, the suction casing 7 has a front wall on the side of the boat 2 extending in the direction of the stern 3, and the suction passage is expanded to open a water inlet 9. The running water flow flowing down the ship bottom 11 is easy to flow along the expanded inclined surface of the suction casing 7. An intake attachment 12 is connected to a lower end of the suction casing 7, and an opening 13a having the same diameter as the water inlet 9 of the suction casing 7 is provided on an upper surface of the intake attachment 12. The intake attachment 12 has an opening on the upper surface thereof. From the portion 13a to the lower surface, it expands in the bow direction, and as shown in FIG.
3b is greatly opened. A wide flange portion 14 is provided around the opening 13 of the intake attachment 12, and the flange portion 14 at the tip thereof is close to the stern 3. Then, the running water flow rising at the rear end of the stern 3 is prevented from entering the gap between the boat 2 and the outboard motor 1, and at the same time, the waves and air are prevented from entering the opening 13 of the intake attachment 12. Therefore, the rectification effect of the running water flow is enhanced to prevent the hull resistance. In addition, the suction casing 7 and the intake attachment 12 are integrally formed, the front wall of the suction casing 7 is extended in the direction of the stern 3 of the boat 2, and the suction flow path is expanded from the upper surface to the lower surface. May be provided on the periphery of the water inlet 9 in such a manner that the flange is brought closer to the stern 3. As shown in FIG. 2, a hydraulic cylinder 15 is supported on the stern 3, and a pedestal 17 of the outboard motor 1 is connected to a piston 16 of the hydraulic cylinder 15. Thus, the position of the water inlet 9 of the suction casing 7 with respect to the ship bottom 11 can be adjusted. Reference numeral 18 denotes an engine connected to the drive shaft 5,
Reference numeral 19 denotes a reverse reverser, reference numeral 20 denotes a reverse reverser nozzle, and reference numeral 21 denotes guide vanes for converting the swirling flow pressurized by the impeller 6 into a linear flow.

[0008]

According to the present invention, there is provided a water jet propulsion type outboard motor as described above, in which the front wall of the suction casing is extended to the vicinity of the stern of the boat, and the suction flow passage is expanded. Since the water inlet is opened, the suction performance and rectification effect can be enhanced. That is, in the conventional water jet propulsion type outboard motor of the horizontal axis mixed flow type, the jet water is jetted toward the water surface at the time of starting the cruising, so that there is a possibility that the water does not enter the sliding state in a short time. In addition, the water jet propulsion type outboard motor that uses a pump casing as a spiral pump has a small amount of water flowing into the pump casing,
Although there was a drawback that there was a risk of stalling at the time of gliding and energy loss also increased, in the present invention, the outboard motor of the vertical-axis diagonal flow type was used, and the suction passage of the suction casing was expanded. Since the stern is extended to the vicinity of the stern, it is easy to recover the dynamic pressure of the running water flowing through the bottom of the stern, and the suction performance is improved. Then, the opening of the intake attachment arranged at the water inlet of the suction casing is expanded downward, and its tip is made to approach the stern, preventing the inflow of waves and air, and increasing the amount of water flowing into the suction casing. And the rectification effect is enhanced. In addition, since the water jet propulsion type outboard motor is supported on the stern so as to be able to move up and down, if it is adjusted according to the weather condition or the cruising condition, the water resistance is reduced, and good gliding becomes possible. Things.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a boat provided with a water jet propulsion type outboard motor according to the present invention.

FIG. 2 is a vertical sectional side view of the water jet propulsion type outboard motor according to the present invention.

FIG. 3 is a longitudinal sectional side view of a main part of the water jet propulsion type outboard motor according to the present invention.

FIG. 4 is a bottom view of the intake attachment according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 outboard motor 2 boat 3 stern 4 pump casing 6 impeller 7 suction casing 8 discharge casing 9 water inlet 12 intake attachment 13 opening 13a top opening

Claims (3)

[Claims] 1. An impeller 6 is mounted on an upright pump casing 4.
An outboard motor that pressurizes water sucked from a submerged suction casing 7 by an impeller 6 of a pump casing 4 and injects pressurized water from a discharge casing 8 opened rearward of the stern to propel the boat 2. 1, the front wall of the suction casing 7 is extended in the direction of the stern 3 of the boat 2, the suction passage is expanded to open the water inlet 9, and the discharge casing 8 connected to the pump casing 4 is A water jet propulsion type outboard motor characterized in that the front half is curved and the rear half is opened rearward in the propulsion direction. 2. An intake attachment 12 having an opening 13 is connected to the water inlet 9 of the suction casing 7, and the upper opening 13a has the same diameter as the water inlet 9 of the suction casing 7, and the intake attachment 12 has the same diameter.
The water jet propulsion type outboard motor according to claim 1, wherein the opening (13) extends from the upper surface to the lower surface in the bow direction, and the tip of the intake attachment (12) approaches the stern (3). 3. The water jet propulsion outboard motor according to claim 1, wherein said water jet propulsion outboard motor 1 is supported on a stern 3 of a boat 2 so as to be able to move up and down.