JPS6366718B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a self-propelled surfjet which has a rope with a throttle grip at the tip of the surfboard and a waterjet propulsion device with an engine installed at the rear of the surfboard. This invention relates to the structure of a waterjet propulsion device and engine exhaust system that obtain propulsive force.

[Conventional technology]

In recent years, self-propelled surf jets have been developed as one of the leisure products for use in the sea, etc., in which a surfboard is equipped with a water jet propulsion device driven by an engine and a person rides on the surf board, and is attracting attention from the public. . However, it is still in the process of development, and in particular, the most important engine, the waterjet propulsion device driven by it, and the engine exhaust system have not been ideally completed.

[Problem to be solved by the invention]

For example, the exhaust gas emitted from the engine has a very high temperature, so if you want to use it naked, consider the safety of the occupants and those around them, and cool it as much as possible and install it on the back side of the board far away from the occupants. It is desirable to discharge into water. In addition, this exhaust gas exhaust system directly communicates with the inside of the engine cylinder, and the surfboard itself often rolls and overturns, especially in the left and right direction, during use.
Naturally, it is conceivable that water may infiltrate into the cylinder from the exhaust system during such an overturn. Therefore, if the engine were to become unusable due to water intrusion every time it capsized, its usability would be extremely poor and it would be completely impossible for the general public to put it to practical use. It is essential that the system is configured as follows. The present invention has been made in view of the above circumstances, and includes providing a waterjet propulsion device in an engine mounting box in which an engine is mounted, and forming an exhaust system from the engine. A plurality of expansion chambers are arranged around the jet injection nozzle, and the expansion chambers are communicated with an exhaust gas outlet opened in the board so that the cooled exhaust gas can be safely discharged into the water,
Furthermore, the exhaust gas inlet of the expansion chamber, the expansion chambers, and the exhaust gas outlet are three-dimensionally bent and communicated, so that only a minimum amount of water can enter the expansion chamber due to the aerodynamic action of the reed valve of the engine intake system in the event of a rollover. To provide a surfjet which prevents water from entering into an engine side from an exhaust gas inlet.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a waterjet propulsion device with an engine at the rear of a surfboard, mounts the engine through an engine mounting box of the surfboard, and installs the engine inside the engine mounting box. A case for accommodating an impeller driven by the engine, an exhaust gas inlet communicating with the exhaust gas passage of the engine, and an exhaust gas expansion chamber are formed, and a water jet injection nozzle of the case for accommodating the impeller is connected to the exhaust gas. In a waterjet propulsion device formed through an expansion chamber, the exhaust gas inlet is formed to protrude a predetermined height into the expansion chamber, and the expansion chamber inside the engine mounting box is connected to the waterjet injection nozzle. A first partition in orthogonal directions and a second partition having two exhaust communication holes form a second expansion chamber, and the second partition and the second partition extend along the water jet injection nozzle. A first expansion chamber and a third expansion chamber are formed by a third partition, and one of the exhaust communication holes connects the first expansion chamber and the second expansion chamber,
The second expansion chamber and the third expansion chamber are connected to each other by a bent passage opening downward through the other exhaust communication hole, and the second expansion chamber of the third expansion chamber is connected to the second expansion chamber of the third expansion chamber.
A horizontal exhaust passage communicating with an exhaust gas outlet formed on the surfboard is formed at the bottom on the opposite side of the partition, and the exhaust gas inflow side of the horizontal exhaust passage is connected and communicated with a vertical exhaust passage at a predetermined height. The exhaust gas inflow opening of the vertical exhaust passage is configured to be located higher than the exhaust gas outflow opening of the bent passage.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. To explain the outline of the surfjet according to the present invention in FIG. 1, reference numeral 1 is a surfboard, and a strong and flexible cable body 3 is attached to the tip of the surfboard 1 by a fixing fitting 2. The first part has a throttle grip 4 which is large enough to be gripped with one hand. A hydraulic cylinder (not shown) is built into the throttle grip 4 so that a predetermined hydraulic pressure is generated when the throttle grip 4 is gripped strongly, and a hose 5 of this hydraulic pressure is connected to a part of the inside of the rope body 3, the fixing metal fittings 2, and the rear inside of the surfboard 1. attached to. The person riding on the surfboard 1 holds the throttle 4.
The system maintains stability by tightening the rope body 3 by gripping it, and adjusts the waterjet propulsion force by adjusting the throttle valve opening of the carburetor, which will be described later, through the oil pressure of the hose 5 depending on the degree of grip. be. Further, a mountain portion 6 is formed at the rear of the surfboard 1, and a hood 7 is removably attached thereto, and a propulsion unit such as an engine, which will be described later, is housed inside the mountain portion 6 and the hood 7. There is. There is a control panel 8 on the mountain part 6 facing forward of the surfboard 1, and this panel 8 has a starter knob 9 for starting the engine and a string 10 tied to the body of the rider to stop the engine in the event of capsizing, etc. It has a kill switch 11, etc. To explain the propulsion section in FIGS. 2 to 4, a storage chamber 12 for an engine, etc., which is open at the top and rear, is formed in the mountain part 6 at the rear of the surfboard 1. At the bottom of this storage chamber 12, a rectangular three-layer structure is formed. An engine mounting box 13 is mounted, and the engine 14 is mounted horizontally on the engine mounting box 13 with the crankshaft 21 being vertical. Further, an engine 1 is provided at the periphery of the engine mounting box 13.
4. A cover 15 is attached to cover almost the upper limit of the surrounding area to prevent water from getting on the engine 14, and there is a similar space between the engine mounting box 13 and the L-shaped front part of the cover 15. A fuel tank 16 having the shape of is installed. As detailed in FIGS. 3 and 4, the engine 14 is, for example, a reed valve type two-stroke, two-cylinder engine, with one side of the crankcase 17 and cylinder 18 fixed directly to the engine mounting box 13, This horizontal cylinder 18
The lower end of a crankshaft 21, which stands perpendicularly to the inner piston 19 via a connecting rod 20, is inserted into the engine mounting box 13, and a magneto 22 and a recoil starter 23 are attached to the upper end of the crankshaft 21. Piston 19 of crankcase 17
An intake manifold 25 is connected to the opposite side via a reed valve 24, a carburetor 26 is attached to this manifold 25, and an exhaust port 27 that opens on the back side of the cylinder 18 is connected to the cylinder 18 itself and the exhaust manifold 28. The exhaust gas passage 29 is configured to guide exhaust gas toward the lower engine mounting box 13 side. Furthermore, the base plate 31 having the coil 30 of the magneto 22, etc. controls the ignition timing by rotating, and the throttle lever 32 protruding from the base plate 31 is integrated with the valve shaft 33 of the throttle valve of the carburetor 26. The arm 34 is interlocked with the arm 34. Also, base plate 3
A hydraulic cylinder 36 is attached near the ear portion 35 of 1 by a bracket 37.
The hose 5 from the throttle grip 4 at the tip of the surfboard 1 is connected to the hose 5, and the piston side of the hydraulic cylinder 36 is engaged with the lug 35 by the rod 38, so that when the throttle grip 4 is gripped, the hose 5 is connected to the hose 5. The generated hydraulic pressure moves the rod 38 on the piston side via the hydraulic cylinder 36, rotates the base plate 31 of the magneto 22 to advance the angle, and operates the arm 34 of the carburetor 26 with the throttle lever 32 to open the throttle valve. When the throttle grip 4 is opened and the throttle grip 4 is released, the base plate 31 and the arm 34 are returned by spring force. The starter knob 9 is connected to the recoil starter 23 via a rope 39, and the kill switch 11 is operated to stop the generation of sparks on the plug 41 side in the electrical system including the magneto 22. The cylinder head, 41 is a plug, and 42 is a cooling water passage. The engine mounting box 13 has a water jet propulsion device 43 therein, and an exhaust system from the engine 14 is formed therein. The waterjet propulsion device 43 is a radial flow type centrifugal pump installed horizontally, and a spiral case 44 is installed in the engine mounting box 1.
This case 4 is installed near the bottom board in case 3.
An impeller 45 connected to the lower end of the engine crankshaft 21 is housed in the engine 4 so as to rotate within a horizontal plane. In addition, the center of the case 44 communicates with a water intake port 46 that opens on the board side directly below the case 44, and the case 44
A water jet injection nozzle 47 from 4 passes through the engine mounting box 13 and reaches a nozzle outlet 48 at the lower rear end of the hood 7. The exhaust system inside the engine mounting box 13 is shown in Figures 3 and 5.
As detailed in the figures to FIG. 10, in a part of the case 44 of the waterjet propulsion device 43 and at the waterjet injection nozzle 47,
A first expansion chamber 54 and a second expansion chamber 55 are formed by a first partition 50 and a second partition 51 in a direction perpendicular to the water jet injection nozzle 47 and a third partition 52 along the water jet injection nozzle 47. , the third expansion chamber 56 is arranged to have a substantially U-shape in plan view, and has an exhaust gas inlet 58 communicating with the exhaust gas passage 29 above the depression 57 near the center of the first expansion chamber 54 . Further, an exhaust communication hole 5 located at the center in the height direction outside the recess 57 of the partition 51 is provided.
9 communicates the first and second expansion chambers 54, 55, and another exhaust communication hole 60 having the same height as the exhaust communication hole 59 communicates the second and third expansion chambers 55, 56. On the third expansion chamber 56 side of the exhaust communication hole 60, a bent passage 61 is provided which bends downward from the side and opens like a faucet. Further, on the wall side of the engine mounting box 13 in the third expansion chamber 56, there is a vertical exhaust passage whose upper part opens at a position higher than the outlet side of the bending passage 61 at approximately 2/3 of the height of the engine mounting box 13. 62 is installed upright, and this vertical exhaust passage 6
2 is connected to an exhaust gas outlet 64 that opens on the surfboard 1 side directly below the water jet injection nozzle 47 through a horizontal exhaust passage 63 at the bottom of the third expansion chamber 56, and the second and third expansion chambers Room 5
At the bottom of 5 and 56, there is a drain screw 65 that also serves to secure the engine mounting box 13 to the surfboard 1 side.
is installed. Since the present invention is constructed in this way, when using the surf jet, first, by strongly pulling the starter knob 9, the recoil starter 23 starts the engine 14.
However, when the engine is started, the engine output is small and the impeller 45 of the waterjet propulsion device 43 rotates at a very low speed together with the crankshaft 21. Therefore, water simply passes through the water inlet 46 to the case 44 of the waterjet propulsion device 43 and the waterjet injection nozzle 47.
flows, and does not produce a jet flow.
The surfboard 1 can be easily stopped by holding it down by hand. Next, a person rides on the surfboard 1 while the engine is operating at low speed, and grips the throttle grip 4 while maintaining stability with the cable 3. Then, as described above, the ignition timing in the magneto 22 is advanced in accordance with the grip, and at the same time, the throttle valve opening of the carburetor 26 is changed, the output of the engine 14 is increased, and the impeller 45 together with the crankshaft 21 is moved at high speed. It rotates. Therefore, a jet stream is ejected rearward from the case 45 of the waterjet propulsion device 43 through the waterjet injection nozzle 47, and the surfboard 1 travels on the water surface at high speed due to the reaction force of the ejected water. During such engine operation, exhaust gas from the exhaust port 27 of the engine 14 passes through the exhaust gas passage 29, enters the first expansion chamber 54 in the engine mounting box 13 through the exhaust gas inlet 58, and enters the water jet injection nozzle 47. The gas is discharged toward the direction, changes direction in the first expansion chamber 54 , and enters the second expansion chamber 55 through the exhaust communication hole 59 . Next, the second expansion chamber 55 crosses the inside of the engine mounting box 13, passes through the exhaust communication hole 60 and the bending passage 61, and enters the third expansion chamber 56. The direction is changed to a vertical exhaust passage 62,
The exhaust gas outlet 64 is reached via a horizontal exhaust passage 63 . Here, the exhaust gas that is discharged from the exhaust gas inlet 58, flows through the first expansion chamber 54, the second expansion chamber 55, and the third expansion chamber 56, and reaches the exhaust gas outlet 64 is constantly cooled by the jet flow. The surfboard is cooled by the exhaust gas pressure and the negative pressure generated at the exhaust gas outlet 64 during running, and is safely discharged into the water on the back side of the surfboard 1 through the exhaust gas outlet 64. By the way, when the engine mounting box 13 is being operated and used normally as described above, even if the engine mounting box 13 is appropriately submerged in water due to the weight of that part and the weight of the person riding on the surfboard 1, the first expansion chamber 54, Water does not enter from the exhaust gas outlet 64 due to the exhaust gas pressure in the second expansion chamber 55 and the third expansion chamber 56. Furthermore, when the operation of the engine 14 is stopped underwater, positive pressure is created in the crankcase 17 and the reed valve 24 is fully closed. Exhaust gas passage 29, first expansion chamber 5
4. The second expansion chamber 55 and the third expansion chamber 56 are kept airtight. Therefore, when the surfboard 1 is in the normal position, only some water enters the horizontal exhaust passage 63 from the exhaust gas outlet 64, but the high vertical exhaust passage 62 prevents water from entering the third expansion chamber 56. ing. On the other hand, to explain the case where a passenger falls from the surfboard 1 while riding and the engine 14 is stopped by the kill switch 11, the surfboard 1 rolls left and right and capsizes. First, the surfboard 1 rolls clockwise as shown in Figure 11a. When capsizing, the exhaust gas outlet 64 is located at the bottom, and the vertical exhaust passage 62 and the horizontal exhaust passage 6 serve as water ingress routes.
3 is on top of the vertical and horizontal exhaust passages 62 and 63 above which light air is retained without escaping, so water does not enter. Even if the exhaust gas outlet 64 is turned in any direction from the inverted state as shown in b, the aerodynamic action is activated again to prevent water from entering. On the other hand, in the case of rolling counterclockwise and capsizing as shown in Fig. 12a, the exhaust gas outlet 64 is at the top and vertical, and the horizontal exhaust passages 62 and 63 are at the bottom. Exhaust gas outlet 6
4, water enters the third expansion chamber 56 through the vertical and horizontal exhaust passages 62, 63. By the way, in general, when the surfboard 1 capsizes, the amount of water that enters is not so large because the surfboard 1 rotates relatively quickly. The water level remains in the third expansion chamber 56 in this state. If you then turn it counterclockwise to raise it, the water in the third expansion chamber 56 will flow backwards through the same path it entered when it entered and go out, but if you turn it counterclockwise in the same way to raise it, it will look like c. In the vicinity where the surfboard 1 becomes vertical, a portion of the water in the third expansion chamber 56 enters the second expansion chamber 55 through the bent passage 61 and the exhaust communication hole 60. In this way, water infiltrates into the second and third expansion chambers 55 and 56 only when the counterclockwise rotation continues once, and the water in the second expansion chamber 55 prevents capsizing due to counterclockwise rolling. At this time, it also enters the first expansion chamber 54 through the exhaust communication hole 59, but this first
In the expansion chamber 54, the exhaust gas inlet 58 protrudes at a predetermined height, and the periphery thereof is widened by the depressions 57, so that there is no large amount of water that would overflow these depressions 57 and the exhaust gas inlet 58. As long as this is possible, water will not infiltrate into the engine side from this exhaust gas inlet 58. Although this rarely happens, in the case of a backward capsize, the first expansion chamber 54 and the second expansion chamber 5
5. The airlock of the third expansion chamber 56 is maintained to prevent water from entering. Furthermore, even when water has entered the first expansion chamber 54, the second expansion chamber 55, and the third expansion chamber 56, they maintain communication although their passage area is reduced. After use, by removing the drain screw 65, the first expansion chamber 54, second expansion chamber 55, and third expansion chamber 56 can be restarted and used.
It is possible to remove the water contained in it.

[Effects of the Invention] As described above, according to the present invention, the first and second
second and third expansion chambers are formed, the exhaust gas inlet of the first expansion chamber is formed to protrude into the first expansion chamber by a predetermined height, and the exhaust gas flows from the second expansion chamber into the third expansion chamber. The exhaust gas first flows downward through the curved passage, and then flows from the bottom to the top.
The exhaust gas passage is formed so that the vertical exhaust passage flows from above to the bottom, and the horizontal exhaust passage flows horizontally to the exhaust gas outlet formed on the surfboard, so that when the surfboard capsizes, at least the exhaust gas Infiltration of water from the gas outlet can be stopped up to the third expansion chamber. Furthermore, even if water reaches the first expansion chamber, the exhaust gas inlet protrudes into the first expansion chamber by a predetermined height, so that water can be stopped from entering the engine.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the appearance of a surfjet to which the present invention is applied, Fig. 2 is a perspective view schematically showing the propulsion section, Fig. 3 is a sectional view of the main part of the present invention, and Fig. 4 is a part thereof. 5 is a side view of FIG. 3, FIGS. 6 to 9 are a sectional view of FIG. A cross-sectional perspective view inside the storage box,
FIGS. 11a and 11b and FIGS. 12a to 12c are cross-sectional views showing the overturned state. 1...Surfboard, 3...Cable body, 4...Throttle grip, 13...Engine mounting box, 14...
Engine, 43... water jet propulsion device,
47... Water jet injection nozzle, 54...
First expansion chamber, 55...Second expansion chamber, 56...
Third expansion chamber, 58...Exhaust gas inlet, 59,6
0... Exhaust communication hole, 61... Bent passage, 62...
Vertical exhaust passage, 63...Horizontal exhaust passage, 64...
Exhaust gas outlet.

Claims (1)

[Claims] 1. A waterjet propulsion device with an engine is provided at the rear of the surfboard, and the engine is mounted through an engine mounting box of the surfboard,
A case for accommodating an impeller driven by the engine, an exhaust gas inlet communicating with the exhaust gas passage of the engine, and an exhaust gas expansion chamber are formed inside the engine mounting box to accommodate the impeller. In a waterjet propulsion device in which a waterjet injection nozzle is formed by penetrating the exhaust gas expansion chamber, the exhaust gas inlet is formed to protrude by a predetermined height into the expansion chamber, and the exhaust gas inlet is formed to protrude by a predetermined height into the expansion chamber, and the waterjet injection nozzle is formed by penetrating the expansion chamber. forming a second expansion chamber with a first partition in a direction perpendicular to the water jet injection nozzle and a second partition having two exhaust communication holes;
A first expansion chamber and a third expansion chamber are formed by the second partition and a third partition extending from the second partition to the water jet injection nozzle. The second expansion chamber is communicated with one of the exhaust communication holes, and the second expansion chamber and the third expansion chamber are communicated with each other through a bent passage opening downward through the other exhaust communication hole. A horizontal exhaust passage communicating with an exhaust gas outlet formed on the surfboard is formed at the bottom of the third expansion chamber on the opposite side from the second partition, and an exhaust gas inflow side of the horizontal exhaust passage is formed. ,
A surf jet characterized in that the surfjet is connected to and communicates with a vertical exhaust passage of a predetermined height, and the exhaust gas inflow opening of the vertical exhaust passage is located higher than the exhaust gas outflow opening of the bent passage.