JPH04112191U - Bottom structure of small personal watercraft - Google Patents

Abstract

(57) [Summary] [Purpose] To simply and easily realize the function of generating a trim angle of the hull and the function of reducing tail slide when turning, etc., by the shape of the pump cover that forms a part of the rear part of the bottom of the ship. [Configuration] A cone cave with an approximately arc-shaped cross section is formed on the bottom of the ship.
The propulsion unit cover at the rear of the bottom of the ship has a cross-sectional shape that, from the tip on the bow side to the rear end on the stern side, changes from a cross-sectional shape that matches the cone cave on the bottom of the ship, to a shape that invaginates from the cone cave into the hull in a substantially rectangular shape. , forming a cone cave part whose cross-sectional area gradually increases.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a bottom structure of a small personal watercraft.

0002

[Conventional technology]

As a small planing boat, it is boarded on the rear deck and has a bar attached to the deck. The type that is operated by the handle of the model is used. Also, it is installed on the deck. A type of vehicle that is operated while sitting on a bench-style seat has also been proposed. The hull of this type of small personal watercraft is generally made of plastic molded deck and hull parts. It is formed of a hollow shell body with two parts joined together, and the engine is installed inside the hull. In addition to driving the propulsion machine that has arrived, the handle is used to operate the steering means. It is configured. Documents disclosing prior art include, for example, Japanese Unexamined Patent Publication No. 62-34 There are No. 897 and Japanese Utility Model Application No. 63-59095.

0003 As the propulsion device, for example, a drive shaft is driven by an engine inside the hull. A jet pump driven through the This jet pump is It obtains thrust by injecting water sucked in from the bottom opening toward the rear from the rear end of the hull. be. In addition, this jet pump can be steered by changing the direction of water jetting. (steering) can also be performed at the same time. In addition, the jet pump is located at the rear of the hull. It is installed in a duct part that is open at the bottom and the bottom of this duct part is connected to the bottom of the ship. covered by a pump cover which forms part of the pump cover.

0004 As the speed of the small personal watercraft described above increases, the dynamic pressure acting on the bottom of the boat increases. It is designed to form a predetermined trim angle (bow lifting angle) and glide on the water. It is measured. In addition, tail slide (sideways at the stern), which is likely to occur during high-speed turns, By controlling the occurrence of slippage, it is possible to ensure course keeping when turning at high speeds or going straight. is requested. In addition, as a means to ensure the ability of the ship to maintain its course, the cross section of the bottom of the ship can be It is possible to form a concave shape (forming a recess with an arcuate cross section in the front and back direction). It is familiar.

[0005]

[Problem that the idea aims to solve]

However, in the conventional technology, the center of gravity is moved to the rear, or the bottom shape of the ship is changed. The trim angle was set to the desired value by changing the trim angle, so the trim angle was secured. The procedure to do so is quite complicated. In addition, the tail slide is exclusively shaped like the bottom of a ship. Since it was reduced by changing the tail slide, the measures to reduce the tail slide were also considerably It was complicated.

[0006] This invention was created in view of these technical issues, and the purpose of this invention is to , a simple method to ensure the correct trim angle and tail slide, especially when cruising at high speeds. An object of the present invention is to provide a bottom structure for a small personal watercraft that can realize a reduction in the amount of water.

[0007]

[Means for solving problems]

This invention has a cone cave bottom and a duct part formed at the rear end of the bottom. The propulsion unit is installed inside the duct, and the open surface of the duct is shaped like a part of the bottom of the ship. In the bottom structure of a small personal watercraft covered with a propulsion unit cover consisting of a , from the tip of the cover on the bow side to the rear end on the stern side, the cone cap on the bottom of the ship increases. Due to the cross-sectional shape that matches the cone cave, the cone cave intrudes into the hull in a roughly rectangular shape. The structure is such that a cone cave part is formed in which the cross-sectional area gradually increases. This achieves the above objective.

[0008]

【Example】

Hereinafter, the present invention will be explained in detail with reference to the drawings. Figure 1 shows a small model to which this invention is applied. 2 is a left side view of FIG. 1, and FIG. FIG. 3 is a rear view taken along line 3-3 shown in FIG. In Figures 1 to 3, plastic molding An engine room 2 is provided in the front half of the hull 1, which is a hollow shell made of An engine 3 is installed in the engine room 2, and a propulsion engine is installed at the rear of the hull 1. Machine 4 is installed. The propulsion device 4 is driven by a drive shaft by the engine 3. It is driven via the foot 5.

[0009] The deck 6 behind the engine room 2 is the part where the pilot is on board. The vertical part consists of a flat riding floor 7 in the center and protruding parts on both sides. Fin portions 8, 8 are formed. Note that the dashed line W in Figures 2 and 3 indicates water. Illustrate the surface. A handle pole 9 is installed at the front of the deck 6 so that it can swing vertically. A bar-type handle 10 rotates at the tip of the handle pole 9. It is attached so that it can be moved (operated). The propulsion device 4 is composed of a jet pump. An injection nozzle 11 is mounted on a shaft at the rear of the jet pump 4 so as to be able to swing from side to side. supported. The steering operation is performed by remotely controlling the injection nozzle 11 using the handle 10. This is done by creating. Furthermore, the control of the engine 3 is controlled by the grip on the handle 10. This is done by operating a throttle lever (not shown) provided at the top. The rider rides on the riding floor 7 and grips the handlebar 10 to operate the vehicle. do.

0010 FIG. 4 is a longitudinal cross-sectional view showing the propulsion unit installed part of the small personal watercraft shown in FIGS. 1 to 3, and FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 4. FIG. In FIGS. 4 and 5, the hull 1 is A duct portion 13 with an open bottom is formed in the center of the rear end of the bottom 12. A propulsion device (jet pump) 4 is attached inside the duct portion 13. The jet pump 4 has a substantially cylindrical pump casing fixed to the duct portion 13. a guide vane (stator vane) 15 fixed within the pump casing 14; An impeller shaft that is rotatably supported by the boss portion of the guide vane 15 and projects forward. 16, and an impeller 17 fixed to the front end of the impeller shaft 16. It is configured. The drive shaft 5 is connected to the pump casing from inside the hull 1. The rear end of the drive shaft 5 is connected to the boss of the impeller 17. It is connected to the part by an integral rotation mechanism (for example, spline fitting, etc.).

[0011] The injection nozzle for steering is provided at the rear end (outlet) of the pump casing 14. 11 is attached so as to be swingable in the left and right direction. Open bottom part of the duct part is covered by the propulsion unit cover (pump cover) 18, except for its front part. Ru. That is, by attaching the propulsion device cover 18, the propulsion device 4 can be At the same time, a bottom opening 19 for sucking water is formed in the front part of the duct part 13. has been done. The water flowing in from the bottom opening 19 increases inside the jet pump 4. The fuel is ejected from the injection nozzle 11 toward the rear of the ship. Note that the propulsion unit cover -18 is attached at a position that forms a continuous surface with the ship's bottom 12, and is connected to the ship's bottom 1. It forms part of 2.

0012 6 is a cross-sectional view showing the shape of the bottom 12 along line 6-6 in FIG. 1, and FIG. is a bottom view of the hull 1 of FIG. 2 viewed from the bottom side. In Figures 6 and 7, the bottom of the ship 12, two cone caves 21, 21 are formed symmetrically on the left and right, and these Drainers 22, 22, one each on the left and right sides, are formed on the outside of the corncave. As shown in the figure, each of the cone caves 21 has a substantially arc-shaped cross section and extends substantially in the front-rear direction. It is formed by grooves extending parallel to each other. In addition, each drainer 22 is arranged as shown in the figure. , formed by protrusions that have a roughly triangular or chevron-shaped cross section and extend approximately parallel to each other in the front-rear direction. There is. Note that the space between the left and right concave 21, 21 forms the center of the bottom 12. The keel 23 has approximately the same width.

[0013] FIG. 8 is a perspective view of the propulsion unit cover (pump cover) 18, and FIG. 9 is a perspective view of the propulsion unit cover (pump cover) 18. A sectional view showing the shape of the ship bottom at the tip of the propulsion unit cover 18 along line 9-9. 10 at the rear end of the propulsion unit cover 18 along line 10-10 in FIG. FIG. 8 to 10, a section of the propulsion unit cover 18 is shown. The surface shape is such that its tip (bow side end) resembles the cone cave shape 2 of the bottom 12 just before it. 1 and 21 to form a continuous surface (Fig. 9), and from this tip As you go to the rear end (stern side end), the inside of the hull 1 from the cone cave shapes 21, 21. The shape gradually changes to a substantially rectangular shape (FIG. 10) that invaginates.

[0014] That is, as shown in FIGS. 8 to 10, the propulsion unit cover 18 has a key on the bottom 12. A keel portion 24 having approximately the same width as the width K of the keel 23 is formed, and the keel portion 24 is formed on both sides of the keel portion 24. The cone cave parts 25, 25 are the cone caves 21, 2 of the ship bottom 12 as shown in FIG. From the same arcuate cross-sectional shape as 1, the cone case of the bottom 12 as shown in FIG. A substantially rectangular shape (in the illustrated example, a substantially vertical surface 26 and a substantially horizontal surface The cross-sectional shape gradually and continuously changes to a substantially right-angled cross-sectional shape consisting of a surface 27. In addition , the change in the cross-sectional area (area of the recess) of the cone cave portion 25 of the propulsion unit cover 18 is It varies depending on the position of the center of gravity of the planing boat, the shape of the bottom, etc., but for example, the cross-sectional area of the tip The ratio of the cross-sectional area X+Y (Fig. 10) of the rear end to (Fig. 9) is approximately 1.1 to 1.4. selected according to the degree. In addition, in the illustrated example, the water cutters 22, 22 of the boat bottom 12 are located on both outer sides of the propulsion unit cover 18, and therefore are located on the bottom 12 itself. It is formed continuously all the way to the stern.

[0015] According to the embodiment described above, the cone cave 21 having a substantially arcuate cross section is provided on the bottom 12 of the ship. 21, the propulsion unit cover 18 constituting the rear part of the boat bottom has a A cross-sectional shape that matches the cone caves 21, 21 of the bottom of the ship as it goes from the end to the rear end. Because of the shape, the cone caves 21, 21 are invaginated into the hull in a substantially rectangular shape. Since a cone cave part 25 is formed that gradually changes in the direction of expansion in the surface shape, it is particularly The dynamic pressure due to the water flow passing through the cone cave parts 25, 25 during fast running is reduced, This has the effect of pulling the stern into the water, thus raising the bow. It is now possible to obtain a trim angle effect (trim angle generation effect).

[0016] Further, on the inner edges of the left and right cone cave parts 25, 25 of the propulsion unit cover 18, Since a substantially vertical surface 26 is formed, lateral force such as when turning at high speed is reduced. It is now possible to efficiently catch fire, reducing tail slide (sideways skidding at the stern). This made it possible to improve course keeping performance. Course keeping due to this tail slide reduction As for the improvement in performance, the effect was particularly effective when turning at high speed, but even when going straight at high speed. A considerable effect was obtained.

[0017] In addition, in the above embodiment, a case where a jet pump is used as the propulsion device 4 is used as an example. Although shown and described, the present invention is applicable when using other types of propulsion devices such as propellers. It can also be applied in the same way, and similar effects can be achieved.

[0018]

[Effect of the idea]

As is clear from the above explanation, according to the present invention, it has a cone cave bottom, In addition, the propulsion device is installed inside the duct part formed at the rear end of the ship's bottom. A small personal watercraft whose open surface of the duct is covered with a propulsion cover that forms part of the bottom of the boat. In the bottom structure, the propulsion unit cover has a section from the tip of the bow side to the stern side of the cover. As you go to the rear end, the cone is The cross-sectional area gradually expands to a cross-sectional shape that indents into the hull from the cave in a roughly rectangular shape. Since the structure is such that a cone cave part is formed, the cone cave part of the cover part is The trim angle generation effect can be obtained by reducing the dynamic pressure caused by the water flow flowing along the Moreover, due to the increased skidding resistance of the cone cave part, it is particularly difficult to A bottom structure for a personal watercraft is provided that can reduce the tail slide of a personal watercraft.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of a small watercraft to which the present invention is applied.

FIG. 2 is a left side view of the small watercraft shown in FIG. 1.

3 is a rear view of the personal watercraft taken along line 3-3 shown in FIG. 2; FIG.

FIG. 4 is a partial vertical cross-sectional view showing the bottom rear part and propulsion unit of an embodiment of a small watercraft to which the present invention is applied.

FIG. 5 is a cross-sectional view of the rear end taken along line 5-5 shown in FIG. 4;

FIG. 6 is a cross-sectional view of the cross-sectional shape of the ship's bottom taken along line 6--6 shown in FIG. 1;

7 is a bottom view showing the bottom of the small watercraft shown in FIG. 1. FIG.

FIG. 8 is a perspective view of a propulsion unit cover of an embodiment of a small watercraft to which the present invention is applied.

9 is a cross-sectional view showing the shape of the ship's bottom at the front end of the propulsion unit cover along line 9-9 shown in FIG. 4. FIG.

10 is a cross-sectional view showing the shape of the ship's bottom at the rear end of the propulsion unit cover along line 10-10 shown in FIG. 4. FIG.

[Explanation of symbols]

1 Hull 3 Engine 4 Propulsion machine (jet pump) 5 Drive shaft 11 Injection nozzle (steering means) 12 Bottom of the ship 13 Duct part (hull) 14 Pump casing 17 Impeller 18 Propulsion unit cover (pump cover) 19 Bottom opening (suction port) 21 Corncave (Bottom) 23 Keel (Bottom) 24 Keel part (propulsion machine cover) 25 Cone cave part (propulsion unit cover) 26 Vertical plane (cone cave part) W water surface X Cross-sectional area of cone cave Y Increase in cross-sectional area of cone cave part K Keel width

Claims (1)

[Scope of utility model registration request] Claim 1: Having a concave bottom, a propulsion device is installed inside a duct portion formed at the rear end of the bottom, and the open surface of the duct portion is covered with a propulsion device cover that forms part of the bottom of the ship. In the bottom structure of a small personal watercraft, the propulsion unit cover has a cross-sectional shape that matches the cone cave of the bottom of the ship as it goes from the tip of the cover on the bow side to the rear end of the cover on the stern side, and then extends from the cone cave into a substantially rectangular shape into the hull. A bottom structure of a small personal watercraft characterized by forming a cone cave part whose cross-sectional area gradually expands into a concave cross-sectional shape.