JPS6216880B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling water intake structure in a marine propulsion device.

Marine propulsion systems generally take in engine cooling water from the outside, such as seawater. For example, in the case of an outboard motor, multiple cooling water inlets are installed on the side of the lower casing in the front and back direction along the water flow direction. It's open. Conventionally, all of these cooling water inlets were opened at an angle toward the front in consideration of cooling water introduction performance. However, especially when cruising at high speeds, positive pressure is applied to the forward water inlet and large negative pressure is applied to the rear water inlet, so water introduced from the front water inlet may be sucked out from the rear water inlet. be. This sucked water collides with the outer surface flow, creating turbulence and generating a vortex behind the water inlet. This eddy current causes the paint on the outer surface of the casing to peel off, which in turn leads to erosion of the lower casing made of aluminum alloy.

The present invention has been made based on the above-mentioned circumstances, and it is an object of the present invention to provide a cooling water intake structure for a marine propulsion device that does not generate vortices behind the cooling water inlet and prevents peeling and corrosion of paint. It is something.

An embodiment of the present invention will be described below based on drawings in which it is applied to an outboard motor.

1 in the figure indicates a casing, and this casing 1
is constructed by connecting an upper casing 2 and a lower casing 3. A cowling 4 is provided at the upper end of the casing 1, and an engine (not shown) is accommodated within the cowling 4. The output shaft 5 of the engine passes vertically through the inside of the casing 1,
It is adapted to drive a propeller 6 provided in the lower casing 3. A cooling water pump 7 is provided midway along the output shaft 5 so as to be driven by the output shaft 5. A suction passage 8 of the cooling water pump 7 is provided in the lower casing 3, and is adapted to introduce seawater, lake water, river water, etc. from a cooling water intake port to be described later. A discharge passage 9 of the cooling water pump 7 is guided upward within the upper casing 2 to cool the engine.

Note that 10 is a bracket, which is attached to the transom 12 of the hull 11.

However, on both sides of the lower casing 3,
Intake ports 13, 13 that are continuous with the suction passage 8 are formed. Inlet bodies 14, 14 shown in FIGS. 3 to 5 are attached to these intake ports 13, 13. The intake body 14 is made of a synthetic resin plate, and a hook 15 formed at the upper end is engaged with a locking part 16 of the lower casing 3, and a bolt 18 is inserted into a bolt insertion hole 17 formed at the lower end to lower the lower casing. It is removably attached by screwing onto the casing 3. This intake body 14
A large number of cooling water inlet ports 20a...20b...2 are formed in rows in the vertical direction, and each row is juxtaposed in the front-back direction.
0c... is opened. In this example,
Three rows of cooling water introduction water are provided along the front-rear direction. And the front two rows of water inlets 20a... and 2
As shown in FIG. 5, the openings 0b are inclined toward the front with respect to the water flow direction A. Also, as shown in FIG. 5, the water inlet ports 20c in the last row are opened so as to face substantially perpendicularly to the water flow direction A. In addition, 21
... are ribs formed on the outer surface at a distance in the vertical direction, and these ribs 21... not only have a reinforcing effect, but also have a rectifying effect because they extend in the front-rear direction.

According to the embodiment with the above configuration, water flows in the direction of arrow A as the propeller 6 is driven to travel. Therefore, water is sucked in from the front two rows of cooling water inlet ports 20a, 20b, and so on, which are opened at an angle toward the front. The cooling water inlet 20c in the last row is
Due to the generation of excess water of the above-mentioned inhaled water and the generation of negative pressure at the outer rear part,
Let the water inside flow out in the direction of arrow B. This arrow B
Since this direction is almost perpendicular to the water flow direction A, the water sucked out in the direction is more likely to head backwards than when it flows forward, and thus the water flowing in the direction of arrow A. turbulence is less likely to occur. As a result, the proportion of eddy currents generated behind the intake body 14 is reduced, and therefore the paint on the lower casing 3 is less likely to peel off, and the aluminum alloy material constituting the lower casing 3 is less likely to be eroded. Particularly during high-speed cruising, the flow of water in the direction of arrow A is large, so a large negative pressure is likely to be generated outside the cooling water inlet 20c in the last row, but due to the above action, the rate of occurrence of turbulent flow and vortex flow is reduced. reduced.

In the above embodiment, a case has been described in which the cooling water inlets 20c in the last row are set almost perpendicular to the water flow direction A, but the present invention can be modified as shown in FIG. The cooling water inlets 60 in the last row may be opened at a rearward angle.

Further, the present invention is not limited to outboard motors, but can also be implemented in cooling water intake ports of inboard and outboard motors, etc.

Furthermore, although the above embodiments have been described using an inlet body, the present invention may be one in which a cooling water inlet is integrally formed in the casing.

As detailed above, according to the present invention, the cooling water inlet at the rear end in the water flow direction is opened perpendicular to the flow direction or inclined rearward, so that the negative pressure generated at the rear can be Therefore, even if water is sucked out from the cooling water inlet at the rear end, the sucked water tends to flow rearward, thereby preventing turbulence or eddies from occurring in the water flow. Therefore, the rate of occurrence of paint peeling, corrosion, etc. is reduced.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a side view of the outboard motor, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 3 is an intake body. FIG. 4 is a sectional view taken along line ``-'' in FIG. 3, FIG. 5 is a sectional view taken along line ``-'' in FIG. 3, and FIG. 6 is a sectional view showing a modification. 1...Casing, 3...Lower casing, 14...
Inlet body, 20a, 20b, 20c, 60...cooling water inlet.

Claims (1)

[Claims] 1. A plurality of cooling water inlets are opened in the longitudinal direction on the side surface along the direction of water flow during cruising, and these cooling water inlets are opened in the direction of water flow. In a marine propulsion device that opens at an angle toward the front, the cooling water inlet located at the rear end in the water flow direction among the cooling water inlets is perpendicular to or rearward to the water flow direction. A cooling water intake structure for a marine propulsion device, characterized by having an inclined opening.