RU2401218C2 - Waterjet for outboard engine - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: proposed water jet comprises: housing 1 with horizontal water duct 2 and exhaust gas ducts 3. Vertical 3 and horizontal 5 shafts arranged in the housing are articulated by gearing 7. Waterjet comprises also impeller 7 fitted on free extension of shaft 5, water intake branch pipe 8 arranged at the bottom of housing 1 and top face 9 intended for communication of Waterjet bottom with engine deadwood bottom part. Besides Waterjet incorporates pump 10 to engine cooling system water feed and gearshift mechanism 11 with link 12. Impeller 7 comprises four blades 13 secured on hub 14. Said hub has axial channels 15 to end in exhaust gas channels 3. Every blade 13 features monotonously increasing thickness from front edge 16 to rear edge 17.

EFFECT: higher reliability of operation nearby water surface.

3 dwg

Description

FIELD OF THE INVENTION

The invention relates to ship propulsion, particularly to propulsion with a jet water jet created using pumps of a rotating type, namely, water-jet propulsion of motor boats.

State of the art

Known jet propulsion device containing a conduit mounted on the shaft of the impeller located inside the conduit, the plane of the output cut of which coincides with the plane of the outgoing edges of the impeller blades, and the bracket, while the shape of the sections of the blades is made wedge with a sharp incoming edge, and at the outgoing edge of each a blade is formed on the side of its injection surface with a stepped protrusion of a height not exceeding 0.05 of the chord length of the impeller blade section (Patent RU No. 2096258 C1, M. cl. B63H 11/0, published 1997.11.20).

Signs of a known water-jet propulsion device, coinciding with the features of the claimed technical solution, are the presence of a conduit mounted on the impeller shaft located inside the conduit, while the shape of the sections of the blades is made wedge with a sharp incoming edge.

The reason that prevents obtaining the required technical result in a known water-jet propulsion device is that the design of the known water-jet propulsion device does not allow it to be used for outboard motors.

Known water cannon for outboard motor, which is closest to the claimed utility model (prototype). The well-known water cannon contains a "snail", which has a specially profiled and calculated exit back, providing the necessary compression of the jet. A water intake is attached to the central part of the “snail”, equipped with removable plates of the protective grill and directing water to the pump. The water cannon also contains a rotor auger, which is made of aluminum or stainless steel, has a conical shape and is rigidly mounted on a vertical shaft, which is inserted directly into the output socket of the engine crankshaft, replacing the standard outboard vertical drive shaft of the outboard motor. This shaft is supported by a special bearing assembly, which has stuffing box seals and is lubricated with grease-resistant grease through grease fittings (see the article “Outboard water-jet motors today” in the journal “Boats and Yachts”, No. 2 (200) March-April 2006, p. 140, middle and right columns).

Signs that are common to the known and claimed technical solutions are the presence of a hull and a water intake.

The reason that prevents obtaining the required technical result in a known technical solution is the presence of a “snail” having a specially profiled and calculated exit back, which provides the necessary compression of the jet, which creates conditions for cavitation to occur.

SUMMARY OF THE INVENTION

The problem to which the invention is directed, is to ensure the stability and reliability of the jet propulsion of a motor boat when it is working near the surface of the water.

The technical result, which mediates the solution of this problem, is to create conditions for guaranteed (under all conditions of operation of the boat) air to reach the impeller blades and the appearance of air cavities on them that are connected to atmospheric air.

The technical result is achieved by the fact that the water cannon for the outboard motor includes a casing with a horizontal water conduit for forming a jet water stream and gas channels for passing exhaust gases from the outboard motor, vertical and horizontal shafts installed in the casing, kinematically connected to each other , and an impeller installed at the outlet of the conduit at the free end of the horizontal shaft, while the housing is equipped with a water inlet, located in the lower part of the hull and hydraulically connected to the water conduit, and the upper end, designed to connect the water jet to the lower part of the deadwood of the outboard motor, and the impeller has blades mounted on the hub, in which radial channels are made, connected with the gas channels of the water cannon for exhaust motor gases through the impeller hub, and each impeller blade is made with a monotonously increasing thickness in the direction from its front edge to its rear cut.

New features of the claimed technical solution consist in the presence of gas channels in the water canister body, in the presence of an impeller, in the hub of which there are radial channels connected to the gas channels of the water jet to exhaust exhaust gases of the motor through the impeller hub, and also in the implementation of each impeller blade with a monotonously increasing thickness in the direction from its front edge to its rear cut.

List of drawings

In Fig.1 schematically shows a General view of the water jet, in Fig.2 - separately in plan the impeller of the water jet, in Fig.3 - view aa in Fig.2.

Information confirming the possibility of carrying out the invention

A water cannon for an outboard motor contains (Fig. 1) a housing 1 with a horizontal water conduit 2 for water passage and with gas channels 3 for passage of exhaust gases of the motor (internal combustion engine); vertical shafts 4 and horizontal 5 installed in the housing; kinematically connected to each other by gear 6; an impeller 7 mounted on the free (right in FIG. 1) end of the shaft 5; the intake pipe 8 located in the lower part of the housing 1; the upper end 9, designed to connect the water jet to the bottom of the stern of the motor. The water cannon also contains a pump 10, designed to pump water of the cooling system of the motor, and a gear engagement mechanism 11 with a thrust 12, designed to turn on and off the rotation transmission from the motor shaft to the jet shaft 4.

The impeller 7 contains (figure 2) four blades 13, mounted on a hub 14, in which axial channels 15 are made, connected in gas channels 3 and designed for the exhaust of the exhaust gases of the motor. Moreover, each blade 13 is made with a monotonously increasing thickness in the direction from its front edge 16 to its rear slice 17, i.e. in the form of a wedge in cross section AA (figure 3).

The operation of the water jet is as follows.

When the gear is engaged by means of traction 12 and mechanism 11, the rotation from the shaft of the outboard motor through the vertical shaft 4, gear 6 and the horizontal shaft 5 is transmitted to the impeller 7. The latter, rotating, draws water from the river through the intake pipe 8, which flows through the conduit 2 in the direction of the impeller 7 and the outlet of the conduit, creating the necessary reactive force. Moreover, due to the wedge-shaped profile of the impeller blades 7, the continuous stream of water flowing through the water conduit 2 is divided into four separate streams, each of which is pressed by the “wedge” of the corresponding blade, which creates the so-called nozzle effect, which increases the jet’s jet thrust. At the same time, the exhaust gases of the outboard motor pass through the channels 3 of the housing 1 and through the channels 15 in the hub 14 of the impeller 7 exit together with water from the water conduit 2, additionally breaking each individual stream into smaller streams. This ensures a guaranteed closure of air cavities arising on the blades 13 with atmospheric air and thereby preventing cavitation that destroys the impeller.

Claims (1)

A water cannon for an outboard motor, comprising a casing with a horizontal water conduit for forming a jet water stream, and gas channels for passing exhaust gases from the outboard motor, vertical and horizontal shafts installed in the casing, kinematically connected to each other, and an impeller installed at the outlet of the water conduit at the free end of the horizontal shaft, while the casing is equipped with a water inlet located at the bottom of the casing and hydraulically ki connected to the water conduit, and the upper end, designed to connect the water jet to the lower part of the deadwood of the outboard motor, and the impeller has blades mounted on the hub, in which there are radial channels connected to the gas channels of the water cannon to exhaust the exhaust gases of the motor through the impeller’s hub, and each impeller blade is made with a monotonously increasing thickness in the direction from its front edge to its rear cut.

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