JPH041294Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a cooling device for a forced air-cooled vertical shaft engine.

<Prior art> In the past, forced air-cooled vertical shaft engines had a centrifugal fan and a fuel tank arranged vertically in the space above the engine body, which caused the problem that the overall height of the engine was high. .

Therefore, in order to reduce the overall height of the engine, we considered installing a fuel tank in the space above the engine body and on one side of the centrifugal fan. However, if a centrifugal fan and a fuel tank are simply installed side by side, the total width of the engine becomes longer and the overall size of the engine becomes larger. In order to obtain this, the diameter of the centrifugal fan cannot be made small.

On the other hand, there is a desire to increase the capacity of the fuel tank as much as possible. However, in order to increase the capacity of the fuel tank, lowering the bottom of the fuel tank to a lower position and increasing the vertical width is a method of supplying fuel through free fall (using height differences). Then, there are some circumstances that I don't want to implement. Additionally, it is conceivable to adopt a system in which a fuel pump is attached, but this would make the engine expensive.

As mentioned above, reducing the diameter of the centrifugal fan is limited in terms of cooling performance, and lowering the bottom of the fuel tank is limited in systems that employ a free fall fuel supply system.

In view of the above, the method shown in Japanese Utility Model Application Publication No. 54-133203 was proposed.

That is, fuel tanks are arranged in parallel on one side of the fan in the space above the engine body with a partition plate in between, and the side surface of the partition plate is used as a wind guiding surface and faces the outer peripheral surface of the fan.

<Problem that the invention attempts to solve> However, the above structure has the following problems.

B Since the structure is such that a partition plate is installed between the fan and the fuel tank that are installed side by side, the gap between the fan and the fuel tank becomes large due to the partition plate, and the width of the fan and fuel tank is increased when the fan and fuel tank are installed side by side. becomes larger, and the entire engine becomes larger.

(b) Furthermore, the closing point of the cooling air passage between the fan and the partition plate, that is, the closest point between the outer peripheral surface of the fan and the partition plate, is formed at the starting end of the air guide surface by the partition plate, so the outer circumference of the fan The distance between the surface and the partition plate becomes wider toward the lower side of the cooling air passage. As a result, the distance between the fuel tank and the fan, which are arranged with the partition plate in between, becomes even larger, and the overall size of the engine becomes even larger.

C. To prevent this, it may be possible to shorten the width of the fuel tank, but this would reduce the capacity of the fuel tank.

This invention was developed because reducing the diameter of the centrifugal fan is limited in terms of cooling performance, and lowering the bottom of the fuel tank is limited in systems that supply fuel by free fall. The aim is to make the vehicle more compact and at the same time increase the capacity of the fuel tank.

<Means for Solving the Problems> In order to achieve the above object, the present invention is constructed as shown in FIGS. 1 to 4, for example.

That is, the fuel tank 4 is arranged in parallel on one side of the centrifugal fan 3 in the space above the engine body 9 of the forced air-cooled vertical shaft engine 1.
The horizontal side surface 4a on the side is made to directly face a part of the outer circumferential surface of the fan 3 as the wind guide surface 7, and a part of the horizontal side surface 4a is made to protrude toward the fan 3 side, and the outer circumference of the fan 3 is extended beyond this protruding end. Insert it into the fuel tank 4 side,
Among the air guide surfaces 7 of the fuel tank 4, an air guide surface starting end 19 located on the upper side in the rotation direction D of the fan 3
A closing point S of the cooling air passage formed between the fan 3 and the air guide surface 7 is provided at a position deviated toward the air guide surface terminal end 20, which is located on the lower side of the fan 3 and the air guide surface 7. .

<Effect> Next, its effect will be explained.

The cooling air generated by the centrifugal fan 3 uses the side surface 4a of the fuel tank 4 as a wind guiding surface 7, and flows while directly contacting this wind guiding surface 7. At this time, since the closing point S of the cooling air passage, which is the closest point to the outer peripheral surface of the fan, is provided at a position offset to the lower side than the starting end 19 of the air guiding surface 7, The air guide surface on the lower side uniformly approaches the outer peripheral surface of the fan.

On the other hand, since the cooling air does not flow between the starting end of the air guide surface and this cutoff point, the air guide surface can be brought as close to the outer peripheral surface of the fan as the cutoff point.

<Example> Next, an example of the present invention will be described based on FIGS. 1 to 4.

The upper space of the engine 1 is covered with a bonnet 2, and inside the bonnet 2, a centrifugal flywheel fan 3 and a fuel tank 4 are arranged side by side.

The fan 3 is fixed to the upper end of a crankshaft 6 that is rotatably supported above and below the crankcase 5.

In the fuel tank 4, a side surface 4a on the side of the fan 3 is formed into a concave shape to form a wind guide surface 7, and a bottom surface 4b of the upper half in the rotation direction D of the fan 3 is formed on the windward side of the cooling air. A cooling windward direction leading-out surface 8 is formed which slopes upward toward.

A portion of the side surface 4a of the fuel tank 4 protrudes toward the fan 3, and the outer periphery of the fan 3 extends beyond this protruding end into the fuel tank 4 side. (See FIGS. 2 and 4) The bonnet 2 is securely fixed to a bracket 10 raised from the engine body 9, and the fuel tank 4 is attached to the bonnet 2 via a stay 11. When the fuel tank 4 is installed close to the fan 3, the air guide surface 7 is located on the lower side of the air guide surface starting end 19, which is located on the upper side in the rotation direction D of the fan 3. At a position deviated toward the terminal end 20 side, a closest portion between the fan outer peripheral surface and the air guiding surface 7, that is, a closing point S of the cooling air passage is formed. (See Fig. 3) In addition, the outer circumferential surface of the fan 3 other than the surface facing the air guide surface 7 of the fuel tank 4 is covered with a thin air guide plate 12, which allows the fan case to is formed.

Note that a part of the stay 11 for attaching the fuel tank 4 to the bonnet 2 extends below the tip of the bonnet 2 through the bottom of the fuel tank 4, and this extended portion 11a has a part that is attached to the fuel tank 4. An engine stop switch 14 is installed so as to be interlocked with the connected fuel cock 13.

In the figure, reference numeral 15 is a recoil starter fixed to the upper surface of the bonnet 2, and 16 is a cooling air inlet formed in the recoil starter 15.

As described above, when the fan 3 rotates, outside air is sucked in from the cooling air inlet 16 of the recoil starter 15, and this sucked cooling air flows into the fuel tank 4.
The cooling air is guided by the air guide surface 7 and the air guide plate 12 of the fuel tank 4, and is sprayed onto the cylinder block 17 and cylinder head 18 of the engine 1 through the cooling air downward outlet surface 8 formed on the bottom surface 4b of the fuel tank 4. and cooled.

At this time, the cooling air generated by the fan 3 flows along the air guide surface 7 and the cooling wind downward outlet surface 8 of the fuel tank 4 while being in direct contact with each other, so that the fuel tank 4 is strongly cooled and the inside of the fuel tank 4 is strongly cooled. of fuel is prevented from heating up.

<Effects> Since the present invention is configured and operates as described above, it has the following effects.

(a) Since the side of the fuel tank is used as a wind guide surface and directly faces the outer circumferential surface of the centrifugal fan, it is possible to eliminate the partition plate for wind guide between the fan and the fuel tank, and the gap between the fan and the fuel tank can be reduced. It can be made smaller, and when the fan and fuel tank are installed side by side, the width becomes smaller, making the entire engine smaller.

(b) In addition, a part of the side surface of the fuel tank is made to protrude toward the fan side, and the outer periphery of the fan is inserted into the fuel tank side beyond this protruding end, so the capacity of the fuel tank is increased by the amount of this protrusion. can do.

(c) Furthermore, the fan is placed at a position of the air guide surface of the fuel tank that is offset from the start of the air guide surface that is located on the upper side in the direction of rotation of the fan toward the end of the air guide surface that is located on the lower side. Compared to the case where the cut-off point is provided at the starting end, the air guide surface can be moved closer to the outer peripheral side of the fan, making it possible to further increase the capacity of the fuel tank while keeping the overall engine compact. be able to,
Engine operating time can be extended.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a perspective view of a forced air-cooled vertical shaft engine, FIG. 2 is a vertical cross-sectional side view of the main parts, FIG. The figure is a perspective view of the fuel tank. 1... Engine, 3... Centrifugal fan, 4... Fuel tank, 4a... Side of 4, 7... Wind guide surface, 9
... Engine body, 19 ... Wind guide surface starting end, 20
... End of the wind guide surface, S ... Closing point of the cooling air passage.

Claims (1)

[Scope of Claim for Utility Model Registration] In the space above the engine body 9 of the forced air-cooled vertical shaft engine 1, a fuel tank 4 is arranged side by side on one horizontal side of the centrifugal fan 3, and the horizontal space on the side of the fan 3 of the fuel tank 4 The side surface 4a serves as a wind guide surface 7 that directly faces a part of the outer circumferential surface of the fan 3, and a part of the horizontal side surface 4a is made to protrude toward the fan 3 side, and beyond this protruding end, the outer circumference of the fan 3 is connected to the fuel tank 4. fan 3 of the air guide surface 7 of the fuel tank 4.
Wind guide surface starting end 1 located on the upper side in the rotation direction D of
A wind guide surface end portion 20 located on the lower side of 9
A fan 3 and a wind guide surface 7 are placed in a position deviated toward the side.
A cooling device for a forced air-cooled vertical shaft engine, characterized in that a closing point S of a cooling air passage is formed between the cooling air passage and the cooling air passage.