JPH032671Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to the structure of an engine cooling device that cools external air by guiding it to a high temperature part such as a cylinder using a cooling fan fixed to a crankshaft.

[Conventional technology]

Engine cooling systems for forced air-cooled engines are generally constructed so that outside air is guided to high-temperature parts such as cylinders and cylinder heads using a cooling fan fixed to the crankshaft.

As this type of engine cooling device for industrial engines, etc., a centrifugal fan is installed on the side of the flywheel (including flywheel magnets, etc.) that is fixed to the crankshaft, and the cooling air from the centrifugal fan is transferred to a spiral case or air guide. A structure that leads to the engine using a plate or the like is used. In this case, the centrifugal fan is provided on the side of the flywheel opposite to the engine (outside).

[Problem that the invention attempts to solve]

However, in conventional engine cooling systems with this type of structure, cooling air does not flow to the inside of the flywheel, that is, to the crankcase side, resulting in insufficient cooling of the crankcase and a drop in engine oil temperature. difficult and therefore
Problems such as deterioration of engine oil properties and reduction in engine cooling ability are likely to occur. Particularly in the recent era of high speed and high output, the number of cases of such problems occurring is increasing.

〔the purpose〕

The purpose of this invention is to solve the problems of the conventional technology, to be able to guide cooling air to the inside of the flywheel, and to actively cool the crankcase and lower part of the cylinder, thereby controlling the engine oil temperature. An object of the present invention is to provide an engine cooling device that can reduce the amount of heat generated by the engine.

[Means for solving problems]

The present invention is an engine cooling system in which a centrifugal fan is installed on a flywheel fixed to a crankshaft.The flywheel is provided with an opening that communicates with both sides of the flywheel, and an axial fan is provided at a position corresponding to the opening for cooling. The above objective is achieved by actively guiding the wind inside the flywheel.

In the above configuration, it is preferable that a heat dissipation rib is formed at a position of the crankcase where the cooling air from the axial fan hits, thereby enhancing the heat dissipation effect.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows a longitudinal sectional view of an engine equipped with an engine cooling device according to an embodiment of the present invention.

In FIG. 1, a crankshaft 2 is rotatably supported on a crankcase 1, and a cylinder 3
The piston 4, which is reciprocatably fitted into the crankshaft 2, is connected to the crankshaft 2 by a connecting rod 5. In the illustrated example, the crankcase 1 and the cylinder 3 are integrally molded.

Engine oil 23 is stored inside the crankcase 1.

A cylinder head 7 forming a combustion chamber 6 is fixed to the upper end of the cylinder 3, and an intake valve 8 and an exhaust valve 9 are mounted on the cylinder head 7. A head cover 10 is attached above the cylinder head 7 to cover intake and exhaust valves 8 and 9 and a valve train (not shown) that drives them.

One end of crankshaft 2 (left end in Figure 1)
is an output shaft 11, and a flywheel (a flywheel magnet in the illustrated example) 12 is fixed on the opposite side (the right side in FIG. 1) of the output shaft 11, and a A centrifugal fan 13 for engine cooling (air cooling) is provided.

A fan housing 14 that covers the centrifugal fan 13 and also serves as a baffle plate is provided on the flywheel 12 side of the engine. A recoil starter 16 is mounted on the fan housing 14 for starting the engine via a starting pulley 15 fixed to the right end of the crankshaft 2.

The fan housing 14 and the cover 17 of the recoil starter 16 have openings 14A and 17A that communicate the outside air with the inside of the fan housing 14.
is formed.

The flywheel 12 is formed with an opening 18 that communicates both sides thereof, that is, the outside where the centrifugal fan 13 is formed, and the engine side (inside), and an axial fan 19 is provided at a position corresponding to the opening 18. There is.

FIG. 2 is an external front view of the opening 18 and the axial fan 19, and FIG. 3 shows the blades of the axial fan 19.

The axial fan 19 is made of a separate component from the flywheel 12 and is fastened onto the crankshaft 2 on the outside of the flywheel 12.

In the illustrated example, the axial fan 19 has six blades 21 extending radially from the boss portion 20, and the opening 18 of the flywheel 12 is formed to match the position of each blade 21. Further, as shown in FIG. 3, the blades 21 have a predetermined angle of attack α so that the rotation of the crankshaft 2 causes air to be blown from the right to the left in FIG. 1 (towards the engine).

Therefore, when the engine is running, the centrifugal fan 13
As a result, air is introduced from the openings 17A and 14A, and cooling air as shown by the solid line in FIG. 1 is generated.
Separately, the axial fan 19 also allows the engine (in particular, the crankcase
Cooling air is generated towards the side of the

Therefore, in the illustrated example, a heat dissipation rib (cooling fan) 22 is formed at a position of the crankcase 1 that is hit by the cooling air (broken line) from the axial flow fan 19.
Cooling of the crankcase 1 is promoted. It is preferable that the heat dissipation rib 22 is formed continuously to the lower part of the cylinder 3 to effectively cool the entire engine.

Cooling air (solid line) generated by the centrifugal fan 13 is guided by a spiral case-shaped fan housing 14 and necessary air guide plates, and is discharged after cooling mainly the cylinder head 7 and cylinder 3.
Further, the cooling air (broken line) generated by the axial fan 19 mainly cools the crankcase 1 and the lower part of the cylinder 3, and then merges with the cooling air from the centrifugal fan 13, and is similarly guided and discharged.

According to the embodiment described above with reference to FIGS. 1 to 3, the opening 18 as an axial cooling air passage is formed in the flywheel 12, and the opening 18
Since the axial fan 19 is provided in response to the It is possible to lower the temperature of engine oil 23 in engine 1.

In conventional engine cooling systems, cooling air does not flow inside the flywheel 12 (on the engine side), resulting in insufficient cooling of the crankcase 1 and engine oil 2.
However, according to the above-mentioned embodiment, by cooling the crankcase 1, the temperature of the engine oil 23 is raised to 110°C to 120°C, for example. The temperature can be easily lowered to below .degree. C., thereby preventing deterioration of oil properties and improving the cooling ability of the engine itself.

4 and 5 show the axial fan 19 connected to the flywheel (or flywheel magnet) 1.
Another example is shown in which it is integrally molded with 2.

In FIGS. 4 and 5, an opening 18 is formed in the flywheel 12 and communicates with both sides of the flywheel 12.
Blades 21 forming an axial fan 19 are integrally molded to extend radially across the opening 18 . The blade 21 in this case is also formed to have a desired angle of attack α in the same way as the blade 21 in FIGS. 1 to 3, and is arranged so as to generate a similar axial cooling air flow (dashed line).

Flywheel 12 shown in FIGS. 4 and 5
Even when using
The configuration is similar to that shown in the figure, and therefore engine cooling is performed in the same manner.

According to the embodiment shown in FIGS. 4 and 5, the same functions and effects as those of the embodiment shown in FIGS. This has the effect of reducing the size (simplifying the structure).

In addition, in each of the above embodiments, the axial flow fan 19
(or blades 21) are disposed outside the flywheel 12, but this is configured to provide a separate axial fan or an integrated axial fan inside the flywheel 12 (on the engine side) or at the same axial position. You can also.

Furthermore, if the engine has a structure in which the flywheel 12 is fixed to the crankshaft 2, the present invention can be applied depending on the type structure of the engine, such as 2-stroke or 4-stroke, the horizontal and vertical axis arrangement of the crankshaft 2, or the number of cylinders. It can be widely applied to various engines regardless.

[Effect of idea]

As is clear from the above explanation, according to the present invention, the crankcase can be cooled by flowing cooling air also inside the flywheel (on the engine side), thereby suppressing the rise in engine oil temperature. An engine cooling device is obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an engine equipped with an engine cooling device according to an embodiment of the present invention, and FIG.
A front view of the flywheel and axial fan seen from the line in the figure, Figure 3 is the line in Figure 2.
FIGS. 4 and 5 are a longitudinal cross-sectional view and a front view (line - in FIG. 4) of a flywheel of an engine cooling device according to another embodiment.
It is. DESCRIPTION OF SYMBOLS 1... Crank case, 2... Crankshaft, 12... Flywheel, 13... Centrifugal fan, 18... Opening, 19... Axial flow fan, 22...
...heat dissipation ribs.

Claims (1)

[Claims for Utility Model Registration] (1) In an engine cooling system in which a centrifugal fan is provided on a flywheel fixed to a crankshaft, an opening communicating with both sides of the flywheel is formed in the flywheel, and a position corresponding to the opening is formed in the flywheel. An engine cooling system equipped with an axial flow fan. (2) The engine cooling device according to claim 1, wherein the axial fan is integrally molded with a flywheel. (3) The engine cooling device according to claim 1 or 2, which is characterized in that heat dissipation ribs are formed in the crankcase at a position where the cooling air from the axial fan hits.