JPH05139380A - Water jet propelling machine - Google Patents

Abstract

PURPOSE:To provide a water jet propelling machine which can be made lighter in weight and reduced in manufacturing cost because a liner is not applied to an impeller housing accommodating an impeller, and has no possibility of electrolytic corrosion, and can further heighten hardness by means of a spray deposit film. CONSTITUTION:An impeller housing 3 and a nozzle 4 are connected to the rear side of an intake duct 1, and an impeller 7 connected to the rear end of a driving shaft 5 rotatably constructed through the intake duct 1 is arranged inside an impeller housing 3, and hard almite treatment is executed on the surface of the impeller housing 3 cast of light alloy, and a ceramic hard spray deposit film 9 is formed on a part to be the outside of the impeller 7 in the inner periphery of the impeller housing 3.

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 machine used for a small boat such as a pleasure boat.

[0002]

2. Description of the Related Art In a small boat such as a pleasure boat, an impeller is attached to the rear end of a drive shaft which is rotated by an engine, and the water sucked from the bottom side is jetted to the stern side by the rotation of the impeller, and the reaction force of the hull is applied to the hull. A water jet propulsion machine is used to move the vehicle forward. See, for example, Japanese Utility Model Publication No. 2-97196.

The impeller housing for accommodating the impeller is cast in a cylindrical shape using a light alloy. At this time, a hard and highly corrosion-resistant stainless steel liner is integrally inserted, and after casting, the impeller housing is The circumference is finished by cutting to the desired accuracy.

[0004]

The mold is expensive to insert the liner into the impeller housing.
Further, after casting, the inner circumference of the liner is cut to obtain accuracy, but the stainless steel liner is hard and has poor workability, which requires a long processing time. Further, since the rigidity of the liner is required, there is a disadvantage that it becomes thick and heavy. In addition, if the impeller housing has cavities or the like, seawater invades to cause rusting, and the volume expands, so that the impeller housing and the liner are separated.

In view of the above points, the present invention provides a water impeller housing for accommodating an impeller, which can be made lighter without using a liner, which can reduce the cost, which does not cause electrolytic corrosion, and which has a sprayed coating with high hardness. Aim to get a jet propulsion machine.

[0006]

In order to achieve the above-mentioned object, a water jet propulsion machine of the present invention has a rear end of a drive shaft in which an impeller housing and a nozzle are connected to a rear side of an intake duct and which is axially mounted on the intake duct. The impeller connected to the end is placed inside the impeller housing, the surface of the impeller housing cast with light alloy is hard-anodized, and the inner part of the impeller housing, which is outside the impeller, has a hard thermal spray coating such as ceramic. Has been formed.

[0007]

The function of the impeller housing is hard alumite treatment, so that it can be insulated and electrolytic corrosion can be prevented. Then, by applying a hard thermal spray coating to the portion of the inner circumference of the impeller housing that is outside the impeller, it is possible to increase hardness and reduce wear. This eliminates the need for a liner, reduces the weight, simplifies the processing, and reduces the cost.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The intake duct 1 communicates with the rear side from the lower suction port 2, and connects the tubular impeller housing 3 to the rear side of the intake duct 1. The tapered nozzle 4 is connected to the rear side of the impeller housing 3. A drive shaft 5 is inserted in the front and rear of the center of the intake duct 1, and the drive shaft 5 is mounted by bearings 6. Drive shaft 5
The front end of is connected to the output end of the engine. An impeller 7 is connected to the rear end of the drive shaft 5, and the impeller 7 is arranged inside the impeller housing 3. A rudder 8 is attached to the rear end of the nozzle 4 so that the rudder 8 can be pivoted left and right on the vertical axis.

The impeller housing 3 is cast from a light alloy into a tubular shape. The finished size of the gap between the impeller 7 and the impeller housing 3 is 0.1 to 0.3 mm.
The engine rotation force can be efficiently converted into propulsion force. Then, considering the sprayed layer, the inner circumference of the impeller housing 3 is cut so that the gap between the outer circumference of the impeller 7 and the impeller housing 3 becomes 0.2 to 05 mm. Then, the surface of the impeller housing 3 is hard-anodized, and as shown in FIGS. 2 and 3, a portion of the inner circumference of the impeller housing 3 that is outside the impeller 7 has a thickness of 0.
With a thickness of 1 to 0.2 mm, ceramic (Al ₂ O ₅ -T
A hard thermal spray coating 9 such as iO ₂ ) is formed so that the finished dimension is within the range of 0.1 to 03 mm. Since the impeller 7 has less runout on the side closer to the bearing 6, as shown in FIG. 4, the sprayed coating 9 may be formed only on the latter half of the impeller 7.

When the impeller 7 is rotated at a high speed by the engine, the water sucked from the lower intake port 2 of the intake duct 1 is injected to the rear side, and the tapered nozzle 4 accelerates the pressure to inject the water rearward. To do. This reaction force advances the hull. When the rudder 8 is steered left and right, the direction of water to be sprayed can be changed to steer the traveling direction of the ship.

[0011]

As described above, according to the present invention, which is configured as described above, the surface of the impeller housing can be treated with hard alumite so as to have an insulating property, and the galvanic corrosion of the impeller housing can be prevented. Can be prevented. Also, by forming a thermal spray coating of hardness on the inner circumference of the impeller housing that is outside the impeller, the impeller housing will wear even when the impeller sucks in sand or when the impeller shakes and contacts the impeller housing. Can be prevented.
As a result, the weight can be reduced as compared with the case where the liner is provided, and the labor for processing can be simplified and the cost can be reduced.
Especially, the impeller housing can be easily formed by die casting, the requirement for rigidity can be reduced, and the weight can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an impeller and an impeller housing showing an embodiment of the present invention.

FIG. 3 is an enlarged vertical cross-sectional view of a main part showing an embodiment of the present invention.

FIG. 4 is an enlarged vertical cross-sectional view of a main part showing another embodiment of the present invention.

[Explanation of symbols]

 1 Intake duct 3 Impeller housing 4 Nozzle 5 Drive shaft 7 Impeller 9 Thermal spray coating.

Claims (1)

[Claims] 1. An impeller housing for connecting a nozzle to an impeller housing on a rear side of the intake duct, and an impeller connected to a rear end of a drive shaft axially mounted on the intake duct inside the impeller housing to cast a light alloy. The surface of the water jet propulsion machine is characterized in that a hard alumite treatment is applied to the surface thereof, and a hard thermal spray coating of ceramic or the like is formed on a portion of the inner circumference of the impeller housing that is outside the impeller.