JP2001048091A - Water suction duct structure for propeller of jet- propelled boat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise caused by water pressure fluctuation by an impeller and to improve a degree of freedom of change in form of a water suction duct. SOLUTION: By fixing a duct component 33 formed by an FRP separate from a hull member 1 to a duct reinforcing member 32 of the hull member 1 via adhesive 35 which is a vibration damping member, vibration transmitted to the duct component 33 becomes difficult to be transmitted to the hull member 1 because the duct component 33 is fixed to the hull member 1 via the vibration damping member 35, even if water pressure fluctuation propagates in water within the water suction duct 11 and is transmitted as vibration to the component 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water suction duct structure for a propulsion device of a jet propulsion boat.

[0002]

2. Description of the Related Art As shown in FIG.
Is composed of an FRP hull member 1 and a deck member 2 integrally joined at their peripheral edges 3, a steering handle 4 is provided near a central portion on the boat, and a seat 5 is moved in a stern direction. It is formed to extend. An engine 6 is mounted near the center of the boat, and a jet propulsion device 7 driven by the engine 6 is installed at the stern bottom.

[0003] As shown in detail in FIG.
A pump chamber 8 is formed in a lower rear portion of the pump chamber 8. A part of the jet propulsion device 7 is installed in the pump chamber 8, and the lower side of the pump chamber 8 is covered with a bottom plate 9. I have.

A water inlet 1 is provided at the bottom of the hull 1.
A water suction duct 11 is formed integrally with the hull member 1 and extends from the water suction port 10 while being curved rearward and upward and connected to the front part of the jet propulsion device 7.

[0005] An impeller 12 is provided in an impeller housing 19 of the jet propulsion device 7.
The second impeller shaft 13 is connected to the water suction duct 11.
And is connected to the drive shaft of the engine 6 through the duct peripheral wall portion in a watertight manner.

[0006] By the rotation of the impeller 12 by the engine 6, the water sucked into the water suction duct 11 from the water suction port 10 at the bottom of the ship is jetted rearward from the nozzle 14 of the jet propulsion machine 7, so that the jet propulsion boat 20 Will be propelled forward. Further, by rotating the nozzle 14 around the vertical axis 15 by the steering handle 4, the jet propulsion boat 20 is turned while being propelled forward. Further, by operating an operation lever (not shown) provided on the steering handle 4, the reverse bucket 17 is moved via the push bull cable 16 to the horizontal shaft 1.
By rotating the jet propulsion boat 20 downward about 8 (the state shown in FIG. 5), the jet propulsion boat 20 is propelled backward.

[0007]

In the jet propulsion boat 20 as described above, when water is sucked into the water suction duct 11 by the rotation of the impeller 12, a pressure fluctuation corresponding to the number of impellers 12 occurs. The pressure fluctuation propagates water in the water suction duct 11 and is transmitted as vibration to the hull (the hull member 1 and the deck member 2), and the vibration is emitted to the outside as noise from the side and upper surfaces of the hull. was there.

Further, since the shape of the water suction duct 11 has a great influence on the top speed of the jet propulsion watercraft 20, when it is desired to change the shape of the water suction duct 11, the water suction duct 11 may be attached to the hull member 1. Since the hull member 1 is integrally formed, a large-scale change of the entire hull member 1 is required, so that the degree of freedom in changing the shape of the water suction duct 11 is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to reduce noise caused by water pressure fluctuation caused by an impeller and to improve the degree of freedom in changing the shape of a water suction duct. It is an object of the present invention to provide a water suction duct structure for a propulsion device of a jet propulsion boat.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a jet propulsion device in which water sucked into a water suction duct from a water suction port at the bottom of a hull member by rotation of an impeller of a jet propulsion device. In the propulsion system of a jet propulsion boat designed to inject fuel backward from the nozzle, the water suction duct is formed of a separate FR from the hull member.
The FRP duct component, which is formed of P, is fixed to the hull member via a vibration damping member, and provides a water suction duct structure for a propulsion device of a jet propulsion boat.

According to the present invention, an FR separate from the hull member is provided.
By fixing the duct component formed by P to the hull member via the vibration damping member, even if the pressure fluctuation of the water propagates through the water in the water suction duct and is transmitted to the duct component as vibration, this duct configuration Since the parts are fixed to the hull member (the hull) via the vibration damping member, the vibration transmitted to the duct components is less likely to be transmitted to the hull member (the hull), and noise is reduced. Further, by forming the duct components by FRP, the weight can be reduced as compared with the case where the duct components are formed of metal such as aluminum.

Further, since the duct components are formed of FRP separate from the hull members, the shape of the water suction duct can be changed only by changing the type of the duct components only. The degree of freedom of change is improved.

According to a second aspect of the present invention, the vibration damping member comprises:
With a configuration in which the duct component is bonded to the hull member by point bonding or line bonding, a vibration damping effect can be provided only by bonding the duct component to the hull member by point or line. It should be noted that by bonding at points or lines, vibration is less likely to be transmitted to the hull member (hull) as compared with full-surface bonding, which is advantageous.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the same components and operations as those in the conventional art are denoted by the same reference numerals, and detailed description is omitted.

As shown in FIG. 1, a water suction port 10 is formed at the bottom of the hull member 1 and a water suction duct 11 extending from the water suction port 10 to bend upward and rearward. 1 is formed.

At the water suction port 10 of the water suction duct 11, a screen 26 for preventing foreign matter inflow is provided in a slightly raised state, and supports a rear end portion 26a of the screen 26 and a lower portion of the water suction duct 11. Is provided.

The front end 26b of the screen 26 is fixed to the inner surface of the water suction duct 11 near the water suction port 10 by bolts 28, and the rear end 26a of the screen 26 is connected to the outer surface of the front end of the lower duct 27. Are fixed by bolts 29. Also, the lower duct 27
It is fixed to the ship bottom (hull member 1) by bolts 30.

The front end of the impeller housing 7a of the jet propulsion device 7 is bolted (not shown) to a base member 31 provided on the rear end wall 8a of the pump chamber 8 corresponding to the rear end of the water suction duct 11. Fixed.

The screen 2 of the water suction duct 11
6 to the rear end wall 8 of the pump chamber 8 from the fixed position of the front end 26b.
The duct portion K between a is formed separately from the hull member 1.

That is, as shown in FIG. 2 and FIG. 3, this duct portion K cuts out the upper surface and both side surfaces from the conventional water suction duct 11, and the cut hole 11a greatly expands above the cut upper surface. An FRP duct reinforcing member 32 having an inverted U-shaped cross section having a protruding bulging portion 32a is fitted therein, and front and rear ends of both side surfaces 32b of the duct reinforcing member 32 are front and rear of both sides of a cut portion of the water suction duct 11. It is joined to the end, i.e., the hull member 1 in a watertight manner. As a result, the duct reinforcing member 32 is
Will be formed.

Also, the front end 32c of the front surface of the bulging portion 32a bulging upward from the cutout hole 11a is cut out.
a, and the rear end 32d of the bulging portion 32a is abutted against the front surface of the rear end wall 8a of the pump chamber 8 (corresponding to the rear edge of the cutout hole 11a) to be joined in a watertight manner.

As a result, the cutout hole 11a is closed in a watertight manner by the duct reinforcing member 32, and the duct reinforcing member 32 becomes a part of the hull member 1. Note that the duct reinforcing member 32 does not necessarily need to be formed separately from the hull member 1, and the swelling portion is integrally formed by greatly swelling only the upper surface upward from the conventional water suction duct 11. There may be.

On the inner surface of both side surfaces 32b of the duct reinforcing member 32, an inverted U-shaped FRP having an upper surface 33a having the same curved shape as the upper surface of the cut water suction duct 11 is provided.
When the duct component 33 is fitted, the lower opening 32e of the bulging portion 32a is closed by the upper surface 33a. In other words, the cut upper surface of the water suction duct 11 is supplemented by the duct component 33.

On the front end 32c side and the rear end 32d side of the duct reinforcing member 32, the upper surface 3 of the duct component 33 is provided.
Opposing portions 32f and 32g are formed to face the front portion 33b and the rear portion 33c of 3a, respectively.

The outer surface of both side surfaces 33d of the duct component 33 has three sides (as shown in FIG. 2, each side surface 33d has a triangular shape in a side view), and the inner surface of both side surfaces 32b of the duct reinforcing member 32. Are bonded to each other with an adhesive 35 by point bonding or line bonding (see FIG. 3).

The upper surface 33 of the duct component 33
a rear portion 33c is provided with a facing portion 32g of the duct reinforcing member 32.
And the front portion 33b of the upper surface 33a is attached to the inner surface of the
It is bonded to the inner surface of the second facing portion 32f by point bonding or line bonding with an adhesive 35 (see FIG. 1).

The duct component 33 is watertightly fixed inside the duct reinforcing member 32 which is a part of the hull member 1 by the point bonding or the line bonding. The adhesive 35 has elasticity, and acts as a vibration damping member due to the elasticity. The pitch of this point bonding or line bonding is suitably about 10 mm.

The impeller shaft 13 of the impeller 12
Extends forward in the water suction duct 11, penetrates a sleeve 45 attached to the upper surface 33 a of the duct component 33 with a bolt 34 in a watertight manner through a sealing member 36, and a through hole in the front surface of the duct reinforcing member 32. 32h, and further through the through hole 37a of the bulkhead 37, and is connected to the drive shaft of the engine 6.

A sleeve 38 through which the impeller shaft 13 penetrates is attached to the through hole 32h of the duct reinforcing member 32. The through portion of the through hole 32h of the sleeve 38 is sealed with a seal material 39 and the sleeve 38
The rear end portion is fitted around the front end portion of the sleeve 45 and is sealed with a seal material 40.

The through hole 37 on the rear surface of the bulkhead 37
a has a sleeve 41 through which the impeller shaft 13 passes.
A rubber pipe 42 is fitted to the rear end of the sleeve 41 and the front end of the sleeve 38.

When the water suction duct 11 is constructed as described above, the duct component 33 formed of FRP separate from the hull member 1 is partially connected to the hull member 1 via an adhesive 35 which is a vibration damping member. Is fixed to the duct reinforcing member 32 constituting the water suction duct 11
Even if the water inside the water suction duct 11 is propagated as vibration to the duct component 33, the duct component 3
3 is fixed to the duct reinforcing member 32 of the hull member 1 via the adhesive 35, so that the vibration transmitted to the duct component 33 of the water suction duct 11 is less likely to be transmitted to the hull member 1 and noise is reduced. I will be.

Further, by forming the duct component 33 of the water suction duct 11 by FRP, the weight can be reduced as compared with a case where the duct is formed of a metal such as aluminum.

Further, since the duct component 33 of the water suction duct 11 is formed of FRP separate from the hull member 1, the shape of the water suction duct 11 can be changed.
Since it is sufficient to change the mold of only the duct component 33, the degree of freedom in changing the shape of the water suction duct 11 is improved.

Further, since the duct component 33 of the water suction duct 11 is bonded to the duct reinforcing member 32 of the hull member 1 by point bonding or wire bonding with the adhesive 35, the duct component 33 is point or line bonded to the duct reinforcing member 32. By simply bonding with a, a vibration damping effect can be provided.

[0035]

As is clear from the above description, the present invention is characterized by fixing the duct component formed of the FRP separate from the hull member to the hull member via the vibration damping member, and Even if the pressure fluctuation propagates through the water in the water suction duct and propagates as vibration to the duct component, the duct component is fixed to the hull member (hull) via the vibration damping member. The vibration transmitted to the hull becomes difficult to transmit to the hull member (hull), and the noise is reduced. Further, by forming the duct components by FRP, the weight can be reduced as compared with the case where the duct components are formed of metal such as aluminum.

Further, since the duct components are formed of FRP separate from the hull members, the shape of the water suction duct can be changed only by changing the type of the duct components only. The degree of freedom of change is improved.

As described in claim 2, if the vibration damping member is an adhesive for bonding the duct component to the hull member by point bonding or line bonding, the vibration damping member is simply bonded to the hull member by dot or line. A vibration damping effect can be provided.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a water suction duct according to the present invention.

FIG. 2 is a perspective view of a water suction duct.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a side view of the jet propulsion boat.

FIG. 5 is a side sectional view of a conventional water suction duct.

[Explanation of symbols]

 7 jet propulsion machine 10 water suction port 11 water suction duct 12 impeller 20 jet propulsion boat 32 duct reinforcing member 33 duct component 35 adhesive (vibration damping member)

Claims (2)

[Claims] 1. A jet propulsion boat propulsion device in which water sucked into a water suction duct from a water suction port at the bottom of a hull member is jetted rearward from a nozzle of the jet propulsion device by rotation of an impeller of the jet propulsion device. Wherein the water suction duct is formed of an FRP separate from the hull member, and the FRP duct component is fixed to the hull member via a vibration damping member. The water suction duct structure of the propulsion unit. 2. The vibration damping member is an adhesive for point-bonding or line-bonding a duct component to a hull member.
3. A water suction duct structure for a propulsion device of a jet propulsion boat according to item 2.