JPS6133221Y2 - - Google Patents

Description

[Detailed description of the invention] The purpose of this invention is to reduce the size of the engine and improve cooling performance by blowing a large amount of cooling air onto the engine without wasting it, regarding a cooling device for a forced air-cooled vertical shaft engine. .

In general, air-cooled vertical-shaft engines have a fuel tank located above the fan case located at the top of the engine body, which not only increases the overall height of the engine, but also exposes the fuel tank to direct sunlight and heat from the engine. However, the temperature of the fuel in the tank increases, causing vapor lock in the fuel supply path.

Therefore, in order to eliminate the above-mentioned drawbacks, the applicant first proposed something as shown in FIG.

This includes a centrifugal fan 31 and a fuel tank 3 inside a bonnet 30 that covers the upper space of the vertical axis engine.
2, and by concavely bending the side wall 32a of the fuel tank 32 to form the air guide surface 33, the fuel tank 32 is brought closer to the centrifugal fan 31, making the entire engine smaller, and the cooling air can be used to cool the fuel tank 3.
2 can be powerfully cooled.

However, in such a case, the air guide surface 33 formed by concavely bending one side wall 32a of the fuel tank 32 and the air guide plate 3 formed around the remaining centrifugal fan 31.
There was a problem in that a gap S was formed between the starting end 34a of the cooling air and the starting end 34a of the cooling air, and the cooling air leaked to the outside from this gap S, resulting in a decrease in the amount of cooling air.

In order to solve this problem, the present invention has one side of the fuel tank greatly concavely curved along the circumferential surface of the centrifugal fan to form part of the air guide surface. The engine is made smaller by moving it closer to the centrifugal fan, and a cooling air leakage prevention device is installed in the gap between the air guide surface and the starting end of the air guide plate, so that the cooling air leaks from the gap to the outside. This system aims to improve cooling performance by preventing air from leaking into the air using a cooling air leakage prevention device.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an overall perspective view of the forced air-cooled vertical shaft engine, FIG. 2 shows a cross-sectional plan view, and FIG. 3 shows a vertical cross-sectional side view of the main parts.

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

The fuel tank 4 has a side surface 4a on the side of the flywheel fan 3 concavely curved to form a wind guiding surface 7, and a bottom surface 4b of the upper half in the rotational direction of the flywheel fan 3 facing upwind of the cooling air. It is formed so as to have an upward slope, thereby forming a cooling windward outlet surface 8 (see FIG. 4).

The fuel tank 4 thus formed is attached via a stay 11 to the bonnet 2 which is securely fixed to a bracket 10 raised from the engine body 9.

In this way, when the fuel tank 4 is attached close to the flywheel fan 3, a cooling air cutoff point C is formed in a part of the air guide surface 7.

Further, the outer peripheral portion of the flywheel fan 3 other than the air guide surface 7 of the fuel tank 4 is covered with a thin air guide plate 12 to form a fan case F.

As described above, the air guide surface 8 formed by concavely curving one side wall 4a of the fuel tank 4 and the starting end 12a of the air guide plate 12 provided along the remainder of the circumferential surface of the fan 3 are free from manufacturing errors and A gap S occurs due to assembly errors.

In order to prevent the cooling air generated by the centrifugal fan 3 from leaking outside from this gap S, a leakage prevention device 19 is provided near the centrifugal fan 3 near the gap S.

As shown in FIG. 3, this cooling air leakage prevention device 19 is connected to a plate from the upper wall 5a of the crankcase 5 so as to close the gap S between the air guide surface 7 and the starting end 12a of the air guide plate 12. It was launched as a.

Incidentally, as shown in FIG. 4, the stay 11 for attaching the fuel tank 4 to the bonnet 2 has a portion that passes below the fuel tank 4 and extends below the tip of the bonnet 2. An engine stop switch 14 is attached to the engine stop switch 11a so as to be interlocked with a fuel cock 13 connected to the fuel tank 4.

Further, a cooling air guide plate 20 is attached to the lower surface 11b of the stay 11 for guiding the cooling air flowing along the cooling air downward outlet surface 8 of the fuel tank 4 to the cowling 18 of the cylinder head 16.

In the figure, reference numeral 15 is a recoil starter fixed to the upper surface of the bonnet 2, and 21 is a cooling air inlet formed in the recoil starter 15.

The action of the cooling air configured as described above will be explained next.

When the flywheel fan 3 rotates, outside air is sucked in from a cooling air inlet 21 provided in the recoil starter 15. Then, the sucked cooling air is guided by the baffle plate 12 to make about three quarters of a turn, and is directed to the cylinder block 17 and cylinder head 16 of the engine 1 by the cooling air downward outlet surface 8 formed on the bottom surface 4b of the fuel tank 4. Cool them by spraying.

At this time, a large amount of cooling air generated by the flywheel fan 3 flows between the air guide surface 7 and the starting end 1 of the air guide plate 12.
Since the leakage prevention device 19 prevents leakage to the outside from the gap S with the fuel tank 2a, a large amount of cooling air flows directly along the air guide surface 7 and the cooling air downward outlet surface 8 of the fuel tank 4, and the fuel tank 4 is strongly The cylinder block 17 and cylinder head 16 of the engine 1 are cooled strongly.

Further, as shown in FIG. 5, a leakage prevention device 19 is attached to the free end 12b of the starting end 12a of the air guide plate 12, and an elastic body 25 such as rubber is attached to the air guide surface 7 formed on the fuel tank 4.
It may be configured such that it comes into contact with the terminal end portion 7b of the.

The present invention is constructed and operates as described above, and has the following effects.

In other words, one side of the fuel tank is greatly concave to form an air guide surface, and by providing this air guide surface facing the cooling fan, the fuel tank can be brought closer to the cooling fan, increasing the overall external size of the engine. Can be made smaller in width. In addition, when the engine is made smaller in this way, the leakage prevention device prevents the engine cooling air from leaking out from the gap created between the air guide surface and the starting end of the air guide plate. Cooling air is powerfully blown onto the engine, greatly improving engine cooling performance.

Moreover, the leakage prevention device has a simple structure that is merely provided to prevent cooling air from leaking out from the gap, and can be implemented at low cost.

In addition, the fuel tank is powerfully cooled with a large amount of cooling air generated by the cooling fan, and the fuel in the fuel tank is kept at a low temperature, eliminating the risk of fire due to fuel evaporation. Vapor lock in the supply path can be effectively prevented.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, FIG. 1 is a perspective view of a forced air-cooled vertical shaft engine, FIG. 2 is a cross-sectional plan view,
Fig. 3 is a sectional view taken along the line shown in Fig. 2, Fig. 4 is a vertical sectional side view of the main part, Fig. 5 is a cross-sectional plan view of the main part showing another embodiment, and Fig. 6 is a schematic cross-sectional plan view of the conventional example. It is. S... Gap, 1... Engine, 2... Bonnet, 3... Centrifugal fan (flywheel fan), 4... Fuel tank, 4a... Side of 4, 4
b... Bottom surface of 4, 7... Air guide surface, 8... Cooling wind downward outlet surface, 9... Engine body, 12... Air guide plate, 12a... Starting end of 12, 19... Leakage prevention device.

Claims (1)

[Scope of utility model registration request] The upper space of the engine body 9 of the forced air-cooled vertical shaft engine 1 is covered with a bonnet 2, and within the bonnet 2, a centrifugal fan 3 and a fuel tank 4 are arranged side by side on the left and right,
An air guide surface 7 is formed on the side surface 4a of the fuel tank 4 in a concave shape facing along a part of the circumferential surface of the fan 3, and an air guide plate 12 is made to face along the remainder of the circumferential surface of the fan 3. 2, and the starting end 12a of the baffle plate 12
A leakage prevention device 19 that prevents cooling air from leaking from the gap S between the air guide plate 12 and the air guide surface 7 is attached near the starting end 12a of the air guide plate 12 and the air guide surface 7. Air-cooled vertical engine cooling system.